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          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities" xlink:label="us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashEquivalentsAtCarryingValue"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber" xlink:label="dei_EntityTaxIdentificationNumber"/>
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          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber" xlink:label="dei_LocalPhoneNumber"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedGain" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedGain"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicByCommonClassTable"/>
          <link:loc xlink:type="locator" xlink:href="catx-20260331.xsd#catx_RecognitionOfOperatingLeaseLiabilityAndRightOfUseAsset" xlink:label="catx_RecognitionOfOperatingLeaseLiabilityAndRightOfUseAsset"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfStockDomain" xlink:label="us-gaap_ClassOfStockDomain"/>
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          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
          <link:loc xlink:type="locator" xlink:href="catx-20260331.xsd#catx_VmtOptionMember" xlink:label="catx_VmtOptionMember"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsAndShortTermInvestments" xlink:label="us-gaap_CashCashEquivalentsAndShortTermInvestments"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueNotFromContractWithCustomer" xlink:label="us-gaap_RevenueNotFromContractWithCustomer"/>
          <link:loc xlink:type="locator" xlink:href="catx-20260331.xsd#catx_StockIssuedDuringPeriodSharesPrefundedWarrantsExercised" xlink:label="catx_StockIssuedDuringPeriodSharesPrefundedWarrantsExercised"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany" xlink:label="dei_EntityEmergingGrowthCompany"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
          <link:loc xlink:type="locator" xlink:href="catx-20260331.xsd#catx_DisposalGroupIncludingDiscontinuedOperationAssetRetirementObligationCurrent" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationAssetRetirementObligationCurrent"/>
          <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss"/>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireBuildings_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments to purchase buildings</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharesAndWarrantsPriceDifference_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the difference between shares and warrants prices.</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharesAndWarrantsPriceDifference_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Shares and warrants, price difference per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityIncorporationStateCountryCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Incorporation, State or Country Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred stock, shares issued (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock, shares issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationInventoryCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Inventory, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationInventoryCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Inventory</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Supplemental schedule of noncash investing and financing activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RoyaltyAgreementPercentageOfNetSalesReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the percentage of net sales receivable as part of a royalty agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RoyaltyAgreementPercentageOfNetSalesReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Royalty Agreement Percentage Of Net Sales Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RoyaltyAgreementPercentageOfNetSalesReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Royalty agreement percentage of net sales receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USGovernmentAgenciesSecuritiesAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US Government Agencies Securities, at Carrying Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USGovernmentAgenciesSecuritiesAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Securities of U.S. government and government agencies</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Plan Name [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCurrentReportingStatus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Current Reporting Status</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USGovernmentAgenciesDebtSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US Government Agencies Debt Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USGovernmentAgenciesDebtSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Securities of U.S. Government and Government Agencies [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ViewpointMolecularTargetingIncMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Viewpoint Molecular Targeting, Inc. [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ViewpointMolecularTargetingIncMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents Viewpoint Molecular Targeting, Inc.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ViewpointMolecularTargetingIncMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Viewpoint Molecular Targeting, Inc. [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpensesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating expenses:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 2 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Level 2 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_CorporateDebtSecuritiesAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Corporate Debt Securities At Carrying Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_CorporateDebtSecuritiesAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Corporate debt securities at carrying value.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_CorporateDebtSecuritiesAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Corporate debt securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and Contingencies Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commitments and Contingencies</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Income (Note 3)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Income, Noncurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common stock, authorized (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares authorized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductOrServiceAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Product and Service [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalPeriodFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Period Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_DebtInstrumentInterestRateStatedPercentage</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument, interest rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityShellCompany_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Shell Company</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cash and Cash Equivalents, at Carrying Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentDiscontinuedOperationsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Discontinued Operations [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentDiscontinuedOperationsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Discontinued Operations [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Maturity of Note Payable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Maturities of Long-Term Debt [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: current portion</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_NotesPayableCurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Notes payable, current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Notes Payable, Current, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesPayableCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Note payable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common stock, issued (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesIssued_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ReserveForEnvironmentalWasteDisposalReduced_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reserve for Environmental Waste Disposal Reduced</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ReserveForEnvironmentalWasteDisposalReduced_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Reserve for environmental waste disposal reduced.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ReserveForEnvironmentalWasteDisposalReduced_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reserve for environmental waste disposal reduced</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OptionAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the option agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OptionAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Option Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OptionAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Option Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LantheusAlphaTherapyLlcMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Lantheus Alpha Therapy, LLC.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LantheusAlphaTherapyLlcMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lantheus Alpha Therapy, LLC [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">AOCI Including Portion Attributable to Noncontrolling Interest [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated Other Comprehensive Income (Loss) [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Combination [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WarrantMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Warrant [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WarrantMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFilerCategory_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Filer Category</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PriorPeriodReclassificationAdjustmentDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Reclassification, Comparability Adjustment [Policy Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PriorPeriodReclassificationAdjustmentDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reclassifications</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities and stockholders' equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_LiabilitiesAndStockholdersEquity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued personnel expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Employee Related Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Employee Related Liabilities, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentForAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amortization of other assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentForAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Amortization, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentForAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Lived Tangible Asset [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Notes Tables</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_TableTextBlock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsInPeriodFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsInPeriodFairValue</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsInPeriodFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Fair value of the options grants in period.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsInPeriodFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock option awards grant in period fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesIssuedPricePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares Issued, Price Per Share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesIssuedPricePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock purchase price per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Goodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNoncashIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Noncash Income (Expense)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNoncashIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Other Noncash Income (Expense), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNoncashIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Other noncash income, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_EffectiveIncomeTaxRateContinuingOperations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Effective income tax rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeStockOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Common Stock Options [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentIncomeInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_SegmentGeographicalDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Geographical [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyNumberOfPlaintiffs_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingency, Number of Plaintiffs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyNumberOfPlaintiffs_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of plaintiff</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Asset-Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Asset-backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetBackedSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Asset-Backed Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsNoncurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Noncurrent assets:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsNoncurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets, Noncurrent [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OtherMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Related to other property plant and equipment not specifically disclosed.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Accounts Receivable, Allowance for Credit Loss, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Accounts Receivable, Allowance for Credit Loss, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts Receivable, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Allowance for doubtful accounts</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional paid-in capital</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional paid-in capital</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetSalesBetween10And15MillionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Relating to net sales between $10 and 15 million.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetSalesBetween10And15MillionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Sales Between 10 And 15 Million [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetSalesBetween10And15MillionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Sales Between $10.0 and 15.0 Million [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentySixPre-FundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand Twenty Six Pre-funded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentySixPre-FundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">2026 Pre-funded Warrants.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Cash and Cash Equivalents [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Company's Cash Equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Granted, Options (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of Options Outstanding, Granted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Stock option awards granted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property and equipment, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Basic loss per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Basic and diluted loss per share (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basic loss per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ChinoCaliforniaMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chino california.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ChinoCaliforniaMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chino California [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ChinoCaliforniaMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Chino California [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total current liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_LiabilitiesCurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_IncreaseDecreaseInAccountsReceivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsReceivable_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Accounts receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustments to reconcile net loss to net cash provided by (used in) operating activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Adjustments to reconcile net loss to net cash used in operating activities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProgenicsApaMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Progenics APA.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProgenicsApaMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Progenics APA [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromSaleAndMaturityOfAvailableForSaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maturities of available-for-sale securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_GTMedicalStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Relating to GT Medical stock.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_GTMedicalStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">G T Medical Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_GTMedicalStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">GT Medical Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_GTMedicalTechnologiesIncMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">GT Medical Technologies, Inc. [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_GTMedicalTechnologiesIncMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">GT Medical Technologies, Inc. [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_GTMedicalTechnologiesIncMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Refers to information regarding the entity GT Medical Technologies, Inc.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RepaymentProvisions_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Repayment provisions.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RepaymentProvisions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Repayment Provisions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RepaymentProvisions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Repayment provisions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stockholders' equity:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stockholders' equity:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntitySmallBusiness_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Small Business</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_statement-statement-note-8-sharebased-compensation-tables_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Note 8 - Share-based Compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated deficit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Total accumulated deficit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated deficit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Accumulated deficit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetAccretionOfDiscountsOnAvailable-For-SaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net accretion of discounts on available-for-sale securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetAccretionOfDiscountsOnAvailable-For-SaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Accretion of Discounts on Available-for-sale Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetAccretionOfDiscountsOnAvailable-For-SaleSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Net accretion of discounts on available-for-sale securities.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Number of Options Outstanding, Forfeited</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock option awards forfeited</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockPricePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock, Price Per Share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockPricePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sale of stock, price per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Intrinsic value associated with exercises</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SeriesBConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Series B convertible preferred stock.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SeriesBConvertiblePreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series B Convertible Preferred Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-Based Compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValueCommonStockAndWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period Value Common Stock And Warrants</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValueCommonStockAndWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Stock issued during period value common stock and warrants.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValueCommonStockAndWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock and Pre-funded Warrants, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AggregateMaximumEstimateSettlementAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Aggregate maximum estimate settlement amount.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AggregateMaximumEstimateSettlementAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Aggregate maximum estimate settlement amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValuePrefundedWarrantsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of stock pursuant to the exercise of Pre-funded Warrants, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValuePrefundedWarrantsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period Value Prefunded Warrants Exercised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValuePrefundedWarrantsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Stock issued during period value prefunded warrants exercised.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseContractualTermAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease Contractual Term [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeasesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Leases [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Lease, Description [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_AmendmentFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amendment Flag</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MaturitiesOfLongTermDebtAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maturities of Long-Term Debt [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_EstimateAggregateCostOfBuildingModifications_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Estimate aggregate cost of building modifications</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_EstimateAggregateCostOfBuildingModifications_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Estimate aggregate cost of building modifications.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_EstimateAggregateCostOfBuildingModifications_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimate aggregate cost of building modifications</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ProductsAndServicesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Product and Service [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingencies [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Warrants to purchase shares of common stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Assets, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total current assets held for sale of discontinued operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current assets held for sale, discontinued operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Liabilities and Equity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">LIABILITIES AND STOCKHOLDERS' EQUITY</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressPostalZipCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Postal Zip Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_NetCashProvidedByUsedInOperatingActivities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash used in operating activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Other Assets, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationOtherCurrentAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other assets, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingCodmProfitLossMeasureHowUsedDescription_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2027</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Debt, Maturity, Year One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less accumulated depreciation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentyFourAtMarketOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Two Thousand Twenty Four At Market Offering Member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentyFourAtMarketOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand Twenty Four At Market Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentyFourAtMarketOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2024 At-the-Market (ATM) Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PromissoryNoteMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Promissory Note [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PromissoryNoteMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents promissory note.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RofoOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">ROFO Option.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RofoOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">ROFO Option [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Portion at Fair Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xlink:role="http://fasb.org/us-gaap/role/label/axisDefault">Portion at Fair Value Measurement [Member] [Default]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressAddressLine1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, Address Line One</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Weighted Average Fair Value of Stock Option Awards Granted and Key Assumptions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hierarchy and NAV [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basic and diluted loss per share:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyAccrualAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Contingency Accrual</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyAccrualAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_LossContingencyAccrualAtCarryingValue</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingencyAccrualAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Estimated liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill and Intangible Assets Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Goodwill and Other Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Measurements, Nonrecurring [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsMeasuredOnNonrecurringBasisTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Cash Equivalents and Short-term Investments Measured at Fair Value on Recurring Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Right of use asset, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Right of use asset</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Right-of-use asset, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Available-for-Sale, Unrealized Loss Position, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Unrealized Loss Position</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale securities, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments to Acquire Debt Securities, Available-for-Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchases of available-for-sale securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Revenue</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sales, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProgenicsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Progenics.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProgenicsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Progenics [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Warrant or Right [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentType_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Type</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangements by Share-Based Payment Award, Options, Vested and Expected to Vest, Outstanding [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Stock Options</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TypeOfArrangementAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collaborative Arrangement and Arrangement Other than Collaborative [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ArrangementsAndNonarrangementTransactionsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collaborative Arrangement and Arrangement Other than Collaborative [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCentralIndexKey_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Central Index Key</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_CoralvilleIAMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Coralville, IA [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_CoralvilleIAMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Coralville, IA.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Company's of Available-for-sale Securities Measured at Fair Value on Recurring Basis</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments, Debt and Equity Securities [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_statement-statement-note-3-loss-per-share-antidilutive-securities-details_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Note 3 - Loss Per Share - Antidilutive Securities (Details)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Public offering.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Public Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Public Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net increase (decrease) in cash and cash equivalents</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOperatingActivitiesSegmentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Activities [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive securities (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total potential dilutive securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_statement-statement-note-10-leases-tables_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Note 10 - Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupClassificationDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group Classification [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfIssuedAndOutstandingCapitalStock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of issued and outstanding capital stock.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfIssuedAndOutstandingCapitalStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Issued And Outstanding Capital Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfIssuedAndOutstandingCapitalStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of issued and outstanding capital stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityInterestIssuedOrIssuableTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Combination, Consideration Transferred, Equity Interest, Type [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common stock, par value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Common Stock, Par or Stated Value Per Share (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, par value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MoneyMarketFundsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Money Market Funds, at Carrying Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MoneyMarketFundsAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Money market fund</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Amortized Cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Available-for-Sale, Amortized Cost, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-Sale Securities, Amortized Cost</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoncashOrPartNoncashAcquisitionNoncashFinancialOrEquityInstrumentConsiderationSharesIssued1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Shares issued in exchange for common stock (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-Sale Securities, Estimated Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Available-for-sale securities, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Available-for-Sale Securities, Estimated Fair Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Issuance of common stock pursuant to exercise options (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Number of Options Outstanding, Exercised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Options exercised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock pursuant to exercise options (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfIncreaseInCommonStockCapitalSharesForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of increase in common stock capital shares for future issuance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfIncreaseInCommonStockCapitalSharesForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Increase In Common Stock Capital Shares For Future Issuance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfIncreaseInCommonStockCapitalSharesForFutureIssuance_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of increase in common stock capital shares for future issuance.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementInputsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Measurement and Measurement Inputs, Recurring and Nonrecurring [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementInputsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Fair Value Measurements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EstimateOfFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Estimate of Fair Value Measurement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EstimateOfFairValueFairValueDisclosureMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimated Fair Value [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TheUnderwritingAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Underwriting Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TheUnderwritingAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">The Underwriting Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TheUnderwritingAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the Underwriting Agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CurrentFiscalYearEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current Fiscal Year End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Long-Term Debt Instruments [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationLossOnClassificationCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount classified as loss of classification attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationLossOnClassificationCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group Including Discontinued Operation Loss On Classification Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationLossOnClassificationCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss recognized on classification as held for sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfBusinessesAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Combination, Number of Businesses Acquired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfBusinessesAcquired_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of affiliated predecessor companies acquired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Restricted cash</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Restricted cash</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentQuarterlyReport_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Quarterly Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationLeaseLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount classified as lease liabilities attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationLeaseLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group Including Discontinued Operation Lease Liabilities Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationLeaseLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_LitigationCaseTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Litigation Case [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressStateOrProvince_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, State or Province</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SaleOfStockMaximumCommissionPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Sale of stock maximum commission percentage.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SaleOfStockMaximumCommissionPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale Of Stock Maximum Commission Percentage</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SaleOfStockMaximumCommissionPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Agent commission fee as a percentage of gross sales price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred stock, shares outstanding (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock, shares outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Comprehensive loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Comprehensive Income (Loss), Net of Tax, Attributable to Parent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Discontinued Operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Warrant or Right [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_StatementGeographicalAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Geographical [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Interest receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccruedInterestReceivableNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Accrued Interest Receivable, Net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Share-based Compensation Expense Recognized for Share-based Compensation Arrangements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, Stock Options Exercised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock pursuant to exercise of options</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Issuance of common stock pursuant to exercise of options</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MunicipalDebtSecuritiesAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Municipal Debt Securities, at Carrying Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MunicipalDebtSecuritiesAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Corporate debt securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Share based compensation arrangements by share based payment award options exercise price.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share Based Compensation Arrangements By Share Based Payment Award Options Exercise Price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Options exercise price per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Subsequent Event [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">2026 (remaining nine months)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other assets, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherAssetsNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other assets, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Number of Options Outstanding, Expired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock option awards expired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_InterestExpenseDebt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InterestExpenseDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">AOCI Attributable to Parent [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated Other Comprehensive Income (Loss) [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsAssumedInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Options assumed, Options (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsAssumedInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Gross number of share options (or share units) assumed during the period.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsAssumedInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Options to purchase shares of common stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsAssumedInPeriodGross_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Number of Options Outstanding, Options assumed</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Cash Equivalents [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ATMAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">A T M Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ATMAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">A T M Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ATMAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">A T M agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Held-to-Maturity [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred stock, $.001 par value; 7,000,000 shares authorized: Series B: 5,000,000 shares allocated; no shares issued and outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock: $0.001 par value; 7,000,000 shares authorized; 5,000,000 designatedSeries B convertible; no shares issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Groups, Including Discontinued Operations [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDisposalGroupsIncludingDiscontinuedOperationsIncomeStatementBalanceSheetAndAdditionalDisclosuresTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Schedule of Discontinued Operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PromissoryNoteForPurchasingLandAndBuildingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Promissory Note for Purchasing Land and Building [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PromissoryNoteForPurchasingLandAndBuildingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents promissory note for purchasing land and building.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferredContingentConsideration_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Asset Acquisition, Consideration Transferred, Contingent Consideration</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferredContingentConsideration_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Consideration for equipment and services pursuant to the MESA and SOWs</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MinimumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Minimum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MinimumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Minimum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FinancialInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instrument [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current assets:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current assets:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gain (Loss) on Sale of Assets and Asset Impairment Charges</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">(Gain) loss recognized on assets held for sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">(Gain) loss recognized on assets held for sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GainLossOnSalesOfAssetsAndAssetImpairmentCharges_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Royalties payable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Inputs, Level 3 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Level 3 [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AdjustmentsToAdditionalPaidInCapitalAssumptionOfStockOptionsAndWarrantsAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Assumption of Viewpoint stock options and warrants at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AdjustmentsToAdditionalPaidInCapitalAssumptionOfStockOptionsAndWarrantsAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">catx_AdjustmentsToAdditionalPaidInCapitalAssumptionOfStockOptionsAndWarrantsAtFairValue</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AdjustmentsToAdditionalPaidInCapitalAssumptionOfStockOptionsAndWarrantsAtFairValue_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount of increase in additional paid in capital (APIC) resulting from the assumption of stock options and warrants at fair value.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Current liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyTransactionsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related Party Transactions [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityInterestIssuedOrIssuableByTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Combination, Consideration Transferred, Equity Interest, Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InvestmentsAndAgreementsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Investments and agreements disclosure.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InvestmentsAndAgreementsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments And Agreements Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InvestmentsAndAgreementsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investments and Agreements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Balances (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Balances (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_SharesOutstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts receivable, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsReceivableNetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts receivable, net (allowance for doubtful accounts was $375 for each period)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingencies_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and contingencies (Note 9)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingencies_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commitments and contingencies (Note 10)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProceedsFromIssuanceOfCommonStockAndPre-FundedWarrantsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from issuance of common stock and Pre-funded Warrants, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProceedsFromIssuanceOfCommonStockAndPre-FundedWarrantsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from issuance of common stock and Pre-funded Warrants, net.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProceedsFromIssuanceOfCommonStockAndPre-FundedWarrantsNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from issuance of common stock and Pre-funded Warrants, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralAndAdministrativeExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">General and Administrative [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralAndAdministrativeExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">General and Administrative Expense [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralAndAdministrativeExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">General and Administrative Expense [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Indefinite-Lived Intangible Assets [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Total lease liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total lease liability, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityReverseStockSplit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reverse stock split</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityReverseStockSplit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stockholders' Equity, Reverse Stock Split</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScenarioForecastMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Forecast [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScenarioForecastMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Forecast [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USTreasuryBillSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US Treasury Bill Securities [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USTreasuryBillSecuritiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">U.S. Treasury Bills [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProceedsFromTheSaleOfCommonStockPursuantToAt-The-MarketOfferingNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds From the Sale of Common Stock Pursuant to At-the-Market Offering, Net1</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProceedsFromTheSaleOfCommonStockPursuantToAt-The-MarketOfferingNet_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Proceeds from the sale of common stock pursuant to at-the-market offering, net.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProceedsFromTheSaleOfCommonStockPursuantToAt-The-MarketOfferingNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from sale of common stock pursuant to at-the-market offering, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MarchTwoThousandTwentyFourInvestmentAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">March two thousand twenty four investment agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MarchTwoThousandTwentyFourInvestmentAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">March Two Thousand Twenty Four Investment Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MarchTwoThousandTwentyFourInvestmentAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">March 2024 Investment Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeLeaseDescriptionTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Lease, Description [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseContractualTermDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease Contractual Term [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Liabilities, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total current liabilities of discontinued operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Current liabilities of discontinued operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Operating Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Total operating expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total operating expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValueWarrantExercises_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of stock pursuant to exercise of common stock warrants</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValueWarrantExercises_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period Value Warrant Exercises</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValueWarrantExercises_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Stock issued during period value warrant exercises.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LossContingenciesTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Loss Contingencies [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Basic and diluted (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basic</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_StatementScenarioAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Scenario [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net gain (loss) from discontinued operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Lived Tangible Asset [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_BofASecuritiesIncMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">BofA Securities, Inc [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_BofASecuritiesIncMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Bof A Securities, Inc [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_BofASecuritiesIncMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">BofA Securities, Inc.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_LongTermDebt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyTransactionsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related Party Transactions Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyTransactionsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Related Parties</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-based compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total stockholders' equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Balances</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Balances</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_StockholdersEquity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred stock, par value (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockParOrStatedValuePerShare_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock, par value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_IndefinitelivedIntangibleAssetsAccumulatedAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Amortization</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_IndefinitelivedIntangibleAssetsAccumulatedAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Accumulated amount of amortization of indefinite-lived assets.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Stockholders' Equity [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharesIssuedPercentOfFullydilutedOutstandingCapitalStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">catx_SharesIssuedPercentOfFullydilutedOutstandingCapitalStock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharesIssuedPercentOfFullydilutedOutstandingCapitalStock_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents number of shares issued as a percentage of fully diluted outstanding capital stock.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharesIssuedPercentOfFullydilutedOutstandingCapitalStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of fully-diluted outstanding capital stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OverAllotmentOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Over-Allotment Option [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OverAllotmentOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Over-Allotment Option [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Leasehold Improvements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Leasehold improvements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireHeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_PaymentsToAcquireHeldToMaturitySecurities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireHeldToMaturitySecurities_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Purchases of held-to-maturity securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProgramLicenseOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Program license option.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ProgramLicenseOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Program License Option [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestWriteoff_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for sale securities, accrued interest writeoff</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestWriteoff_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Accrued Interest Writeoff</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument, Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Equity in loss of affiliate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Income (Loss) from Equity Method Investments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity in loss of affiliate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel">Loss on equity method investment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentPeriodicPayment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_DebtInstrumentPeriodicPayment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentPeriodicPayment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument, periodic payment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Liabilities, Current [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Liabilities held for sale of discontinued operations, current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentReportingCodmIndividualTitleAndPositionOrGroupOrCommitteeNameExtensibleEnumeration_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InProcessResearchAndDevelopmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">In Process Research and Development [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InProcessResearchAndDevelopmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">In Process Research and Development (IPR&amp;D) [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PlanNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Plan Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BuildingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Building [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BuildingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Building</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CertificatesOfDepositMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Certificates of Deposit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CertificatesOfDepositMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Certificates of Deposit [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related and Nonrelated Parties [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_VmtOptionOrProgramLicenseOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">VMT option or program license option.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_VmtOptionOrProgramLicenseOptionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">VMT Option or Program License Option [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityAddressCityOrTown_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Address, City or Town</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_NumberOfReportableSegments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Number of reportable segments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_SecurityExchangeName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Security Exchange Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Indefinite-Lived Intangible Assets (Excluding Goodwill)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Indefinite-Lived Intangible Assets (Excluding Goodwill), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Indefinite-Lived Intangible Assets (Excluding Goodwill), Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Indefinite-Lived Intangible Assets (Excluding Goodwill), Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Intangible assets, in-process research and development</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PrefundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Relating to Prefunded Warrants.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PrefundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Prefunded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PrefundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Prefunded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PrefundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Pre-funded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property and equipment, gross</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntangibleAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other Intangible Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IntangibleAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Intangible Assets Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_CounterpartyNameAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Counterparty Name [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net loss from continuing operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net loss from continuing operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LeaseWithEnergyNorthwestMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease With Energy Northwest [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LeaseWithEnergyNorthwestMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents lease with Energy Northwest.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stock-based compensation expense on discontinued operations</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MaximumAmountOfSecuritiesOfferAndSale_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Maximum amount of securities offer and sale.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MaximumAmountOfSecuritiesOfferAndSale_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maximum Amount Of Securities Offer And Sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MaximumAmountOfSecuritiesOfferAndSale_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum amount of securities offer and sale</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccruedRoyaltiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Royalties payable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccruedRoyaltiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accrued Royalties, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities, Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementBasisAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Basis [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statistical Measurement [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Warrant exercise price per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total current assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_AssetsCurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_AllocatedShareBasedCompensationExpense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AllocatedShareBasedCompensationExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Noncash or Part Noncash Acquisition, Fixed Assets Acquired</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NoncashOrPartNoncashAcquisitionFixedAssetsAcquired1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additions to property and equipment in accounts payable and accrued expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentPeriodEndDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Period End Date</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Hierarchy and NAV [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LantheusInvestmentAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents Lantheus Investment Agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LantheusInvestmentAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lantheus Investment Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LantheusInvestmentAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lantheus Investment Agreement</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LantheusInvestmentAgreementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Lantheus Investment Agreement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRedeemedOrCalledDuringPeriodValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cancellation of fractional shares due to the 1-for-10 reverse stock split</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRedeemedOrCalledDuringPeriodValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Redeemed or Called During Period, Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfFinancialPositionAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Financial Position [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Assets, Current [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Assets held for sale of discontinued operations, current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_March2024PrivatePlacementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the March 2024 private placement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_March2024PrivatePlacementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">March 2024 Private Placement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_March2024PrivatePlacementMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">March 2024 Private Placement [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Security, Excluded EPS Calculation [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementClassOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Class of Stock [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Non-current liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LiabilitiesOtherThanLongTermDebtNoncurrentAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Noncurrent liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale securities, realized gains or losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Realized Gain (Loss)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Available-for-Sale, Realized Gain (Loss), Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetSalesGreaterThan15MillionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Relating to net sales greater than $15 million.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetSalesGreaterThan15MillionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Sales Greater Than 15 Million [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetSalesGreaterThan15MillionMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Sales Greater Than $15.0 Million [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfChangeInAssetRetirementObligationTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Change in Asset Retirement Obligation [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Liabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_Liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseDiscountRate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_LesseeOperatingLeaseDiscountRate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseDiscountRate_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lessee, operating lease, discount rate</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Financial Instruments [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AccruedInterestOnHeldToMaturityInvestments_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Accrued interest on held-to-maturity investments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AccruedInterestOnHeldToMaturityInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accrued Interest on Held to Maturity Investments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AccruedInterestOnHeldToMaturityInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Accrued Interest on Held to Maturity Investments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodSharesCommonStockWarrantExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock pursuant to exercise of warrants (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodSharesCommonStockWarrantExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period Shares Common Stock Warrant Exercised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodSharesCommonStockWarrantExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Stock issued during period shares common stock warrant exercised.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeferredRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Deferred Revenue</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInDeferredRevenue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Deferred Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OfficeSpaceWithUnicoPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Office Space With Unico Properties [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OfficeSpaceWithUnicoPropertiesMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents Office Space With Unico Properties.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/label">2026</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2028</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Groups, Including Discontinued Operations [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_May2024PreFundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">May 2024 Pre-funded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_May2024PreFundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">May 2024 pre-funded warrants.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Indefinite-Lived Intangible Assets, Major Class Name [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale securities, that were in a gross unrealized loss position for than 12 months or more</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Weighted Average Number of Shares Outstanding, Diluted, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Weighted Average Number of Shares Outstanding, Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityFileNumber_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity File Number</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:role="http://www.xbrl.org/2009/role/netLabel">Unrealized gain (loss) on available-for-sale securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Unrealized gain on available-for-sale securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrealized (loss) gain on available-for-sale securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CoverAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cover [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValueAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Cash and Cash Equivalent [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DebtInstrumentNumberOfPaymentInstallment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">catx_DebtInstrumentNumberOfPaymentInstallment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DebtInstrumentNumberOfPaymentInstallment_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents number of installment to pay debt.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DebtInstrumentNumberOfPaymentInstallment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument, number of monthly payments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accounts payable and accrued expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Prepaid expenses and other current assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Prepaid expenses and other current assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InterestAndOtherExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Interest and other expense.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InterestAndOtherExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Interest and Other Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InterestAndOtherExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Interest and other expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InterestAndOtherExpense_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Interest and other expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementsBySharebasedPaymentAwardOptionsAssumedInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Options assumed, Price (in dollars per share)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementsBySharebasedPaymentAwardOptionsAssumedInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementsBySharebasedPaymentAwardOptionsAssumedInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Options exercise price per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_SharebasedCompensationArrangementsBySharebasedPaymentAwardOptionsAssumedInPeriodWeightedAverageExercisePrice_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Weighted Average Exercise Price, Options assumed</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ScenarioUnspecifiedDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Scenario [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockNameOfTransactionDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GeneralAndAdministrativeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">General and administrative</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SeriesBPreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Series B Preferred Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SeriesBPreferredStockMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Series B Preferred Stock [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValueWarrantsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock issued during period value warrants Exercised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValueWarrantsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Stock issued during period value warrants Exercised.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringPeriodValueWarrantsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of stock pursuant to exercise of common stock warrants</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesAcquisitions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Shares, Acquisitions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodSharesAcquisitions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock in exchange for Viewpoint common stock, net(in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NonRule10B51ArrangementModifiedFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Non-Rule 10b5-1 Arrangement Modified [Flag]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NonRule10B51ArrangementModifiedFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Non-Rule 10b5-1 Arrangement Modified Flag.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NonRule10B51ArrangementModifiedFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Non-Rule 10b5-1 Arrangement Modified</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringSharesCommonStockWarrantExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock pursuant to exercise of warrants (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringSharesCommonStockWarrantExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Shares Common Stock Warrant Exercised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockIssuedDuringSharesCommonStockWarrantExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Stock issued during shares common stock warrant exercised.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSoldAndEstimatedReductionOfReserve_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal group including discontinued operation, costs of goods sold and estimated reduction of reserve</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSoldAndEstimatedReductionOfReserve_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Disposal group including discontinued operation, costs of goods sold and estimated reduction of reserve.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSoldAndEstimatedReductionOfReserve_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cost of sales</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InvestmentAgreementContingentAmountOfGrossProceedsRaised_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the amount of gross proceeds raised as part of an investment agreement.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InvestmentAgreementContingentAmountOfGrossProceedsRaised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment Agreement Contingent Amount Of Gross Proceeds Raised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InvestmentAgreementContingentAmountOfGrossProceedsRaised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Investment agreement, contingent amount of gross proceeds raised</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_OperatingLeaseExpense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease, expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_UnderwrittenOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_UnderwrittenOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Underwritten Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_UnderwrittenOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Underwritten Offering.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Liability, to be Paid, Maturity [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Future Operating Lease Payments and Lease Liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_EstimatedReductionOfReserveFromHazardousWasteDisposalVendor_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimated reduction of reserve from hazardous waste disposal vendor</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_EstimatedReductionOfReserveFromHazardousWasteDisposalVendor_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Estimated Reduction of Reserve from Hazardous Waste Disposal Vendor</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_EstimatedReductionOfReserveFromHazardousWasteDisposalVendor_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Estimated reduction of reserve from hazardous haste disposal vendor.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Consideration</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimated fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Depreciation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Depreciation_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Depreciation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Depreciation, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Depreciation_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Depreciation</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseTermOfContract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Lease, Term of Contract</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureAndSignificantAccountingPoliciesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureAndSignificantAccountingPoliciesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Basis of Presentation and Summary of Significant Accounting Policies</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common stock, outstanding (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock, shares outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Lease liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: current portion</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredRentCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Base prepaid rent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredRentCredit_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Rent Credit</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentTransitionReport_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Transition Report</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Short-term investments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Short-term investments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShortTermInvestments_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Short-Term Investments, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total operating expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingExpenses_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_OperatingExpenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResearchAndDevelopmentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Research and development</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationResearchAndDevelopmentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount of research and development expense attributable to disposal group, including, but not limited to, discontinued operation.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationResearchAndDevelopmentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group Including Discontinued Operation Research and Development Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationResearchAndDevelopmentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Research and development</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeasesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lessee, Operating Leases [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeasesTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Leases</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Cash Flows [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Issuance of common stock, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, New Issues</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueNewIssues_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amount raised through selling of equity</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SegmentOperatingActivitiesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Activities [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Loss Per Share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DiscontinuedOperationsAndDisposalGroupsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Discontinued Operations and Disposal Groups [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Financial instruments measured at fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Discontinued Operations, Disposed of by Sale [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Discontinued Operations, Disposed of by Sale [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockConsiderationReceivedPerTransaction_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock, Consideration Received Per Transaction</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SaleOfStockConsiderationReceivedPerTransaction_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Aggregate sales price</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Net loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationPropertyRightOfUseAssetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount classified as right of use asset attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationPropertyRightOfUseAssetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group Including Discontinued Operation Property Right Of Use Asset Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationPropertyRightOfUseAssetCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Right-of-use asset, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermPurchaseCommitmentAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Purchasing commitment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermPurchaseCommitmentAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Long-Term Purchase Commitment, Amount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryWriteDown_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Write-off of inventory associated with discontinued product</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryWriteDown_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Write-off of inventory associated with discontinued product</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InventoryWriteDown_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Write-off of inventory associated with discontinued product</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInInventories_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Inventory</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInInventories_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Increase (Decrease) in Inventories</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInInventories_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Increase (Decrease) in Inventories, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Debt instrument balloon payment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_DebtInstrumentPeriodicPaymentTermsBalloonPaymentToBePaid</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentySixRegisteredOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand Twenty Six Registered Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentySixRegisteredOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Two thousand twenty six registered offering.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentySixRegisteredOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2026 Registered Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AdjustmentsToAdditionalPaidInCapitalIssuanceOfPreFundedWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Adjustments to additional paid in capital, issuance of pre-funded warrants.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AdjustmentsToAdditionalPaidInCapitalIssuanceOfPreFundedWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Adjustments To Additional Paid In Capital, Issuance of Pre-funded Warrants</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AdjustmentsToAdditionalPaidInCapitalIssuanceOfPreFundedWarrants_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of Pre-funded Warrants, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNonoperatingIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Nonoperating Income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNonoperatingIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other income from a related party</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherNonoperatingIncome_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Other income from a related party (Note 3)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentySixOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Two Thousand Twenty Six Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_TwoThousandTwentySixOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">2026 Offering.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareBasicLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_Rule10B51ArrModifiedFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Rule 10b 51 Arr Modified [Flag]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_Rule10B51ArrModifiedFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Rule 10b 51 Arr Modified Flag.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_Rule10B51ArrModifiedFlag_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Rule 10b5-1 Arrangement Modified</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Assets [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">ASSETS</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ConstructionInProgressMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Construction in Progress [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Prepaid expenses and other current assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RepaymentsOfDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_RepaymentsOfDebt</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RepaymentsOfDebt_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Principal payments</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialPaperAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commercial Paper, at Carrying Value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommercialPaperAtCarryingValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Commercial paper</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_DocumentFiscalYearFocus_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Document Fiscal Year Focus</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">CASH FLOWS FROM INVESTING ACTIVITIES:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentOfOutstandingShares_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the percent of outstanding shares.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentOfOutstandingShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percent Of Outstanding Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentOfOutstandingShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percent of outstanding shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Research and Development [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Research and Development Expense [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ResearchAndDevelopmentExpenseMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Research and Development Expense [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-Sale Securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfOwnershipConsideredForWarrantExerciseTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of ownership considered for warrant exercise</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfOwnershipConsideredForWarrantExerciseTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Percentage Of Ownership Considered for Warrant Exercise Two</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfOwnershipConsideredForWarrantExerciseTwo_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of ownership considered for warrant exercise two.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OneTimePaymentReceivedForRightsGranted_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">One-time payment received for rights granted.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OneTimePaymentReceivedForRightsGranted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">One-Time Payment Received For Rights Granted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OneTimePaymentReceivedForRightsGranted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">One-time payment received for rights granted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from sales of common stock, pursuant to exercise of option</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from sales of common stock, pursuant to exercise of options</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueDisclosuresAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value Disclosures [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommitmentsAndContingenciesDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Commitments and Contingencies Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueAcquisitions_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Issued During Period, Value, Acquisitions</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockIssuedDuringPeriodValueAcquisitions_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Issuance of common stock in exchange for Viewpoint common stock, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_Available-For-SaleSecuritiesMaturities_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-Sale Securities , Maturities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_Available-For-SaleSecuritiesMaturities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Available-for-Sale Securities , Maturities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_Available-For-SaleSecuritiesMaturities_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Available-for-Sale Securities ,Maturities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/label">2025</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2027</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfIndefiniteLivedIntangibleAssetsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Intangible Asset, Indefinite-Lived [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Instrument [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetSalesOf10MillionOrLessMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Relating to net sales of $ 10 million or less.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetSalesOf10MillionOrLessMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Net Sales Of 10 Million Or Less [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NetSalesOf10MillionOrLessMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Net Sales of $10.0 Million or Less [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Payment Arrangement [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Unrecognized compensation expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_EstimatedHazardousWasteRemovalLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Estimated hazardous waste removal liability.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_EstimatedHazardousWasteRemovalLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Estimated Hazardous Waste Removal Liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_EstimatedHazardousWasteRemovalLiability_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Estimated hazardous waste removal liability</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsidiarySaleOfStockAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Sale of Stock [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockholderPlaintiffSettlementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stockholder Plaintiff Settlements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockholderPlaintiffSettlementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Related to stockholder plaintiff settlements.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_StockholderPlaintiffSettlementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Stockholder Plaintiff Settlements</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_NetCashProvidedByUsedInInvestingActivities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Net cash used in investing activities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_Security12bTitle_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Title of 12(b) Security</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_JanuaryTwoThousandTwentyFourPreFundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">January 2024 Pre-funded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_JanuaryTwoThousandTwentyFourPreFundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">January Two Thousand Twenty Four Pre-funded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_JanuaryTwoThousandTwentyFourPreFundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">January two thousand twenty four pre-funded warrants.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MaximumIncreaseOrDecreaseInOwnershipPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Maximum increase or decrease in ownership percentage.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MaximumIncreaseOrDecreaseInOwnershipPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maximum Increase Or Decrease In Ownership Percentage</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MaximumIncreaseOrDecreaseInOwnershipPercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum increase or decrease in ownership percentage</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MoneyMarketFundsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Money Market Funds [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_MoneyMarketFundsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Money Market Fund [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related and Nonrelated Parties [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Allowance for Credit Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel">Debt Securities, Available-for-Sale, Allowance for Credit Loss, Ending Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Debt Securities, Available-for-Sale, Allowance for Credit Loss, Beginning Balance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Debt Securities, Available-for-Sale, Allowance for Credit Loss, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Credit allowance</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Collaborative Arrangement and Arrangement Other than Collaborative [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MaximumAmountOfSecuritiesOfferAndSell_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Maximum amount of securities offer and sell.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MaximumAmountOfSecuritiesOfferAndSell_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maximum Amount of Securities Offer and Sell</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MaximumAmountOfSecuritiesOfferAndSell_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum amount of securities offer and sell</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MayTwoThousandTwentyFourPreFundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">May 2024 Pre-funded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MayTwoThousandTwentyFourPreFundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">May Two Thousand Twenty Four Pre-funded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MayTwoThousandTwentyFourPreFundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">May two thousand twenty four pre-funded warrants.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRedeemedOrCalledDuringPeriodShares_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Cancellation of fractional shares due to the 1-for-10 reverse stock split (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRedeemedOrCalledDuringPeriodShares_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Cancellation of fractional shares due to the 1-for-10 reverse stock split (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockRedeemedOrCalledDuringPeriodShares_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Stock Redeemed or Called During Period, Shares</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/label">2024 (remaining three months)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">2026 (remaining three months)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Other noncurrent liabilities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Other Liabilities, Noncurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ConsolidatedEntitiesAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Consolidated Entities [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_LegalEntityAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Legal Entity [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Changes in operating assets and liabilities:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OppenheimerCoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the Oppenheimer &amp; Co.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OppenheimerCoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Oppenheimer Co [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OppenheimerCoMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Oppenheimer &amp; Co [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Property and Equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Recurring and Nonrecurring [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_January2024PublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">January 2024 Public Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_January2024PublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">January 2024 public offering.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InvestmentAgreementsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Investment agreements.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_InvestmentAgreementsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Investment Agreements [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Additional Paid-in Capital [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additional Paid-in Capital [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Frequency [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statement of Income Location, Balance [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AmendedTwoThousandTwentyIncentivePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Amended 2020 Incentive Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AmendedTwoThousandTwentyIncentivePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Amended Two Thousand Twenty Incentive Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_AmendedTwoThousandTwentyIncentivePlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amended two thousand twenty incentive plan.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_TradingSymbol_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Trading Symbol</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property and Equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related Party Transaction [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RegisteredOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Registered Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_RegisteredOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Registered offering.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_SubsequentEventTypeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Subsequent Event Type [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_JanuaryTwoThousandTwentyFourPublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">January two thousand twenty four public offering.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_JanuaryTwoThousandTwentyFourPublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">January Two Thousand Twenty Four Public Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_JanuaryTwoThousandTwentyFourPublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">January 2024 Public Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationPrepaidAndOtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group, Including Discontinued Operation, Prepaid and Other Assets, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupIncludingDiscontinuedOperationPrepaidAndOtherAssetsCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Prepaid expenses and other current assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued personnel expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Employee-related Liabilities, Current</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Employee-related Liabilities, Current, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">CASH FLOWS FROM FINANCING ACTIVITIES:</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Fair Value, Recurring [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Less: imputed interest</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PlacementAgentsCashFeePercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Represents the cash fee percentage.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PlacementAgentsCashFeePercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Placement Agents Cash Fee Percentage</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PlacementAgentsCashFeePercentage_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Placement agents cash fee, percentage</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Components [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonoperatingIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_NonoperatingIncomeExpense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NonoperatingIncomeExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total non-operating income, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquityComponentDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equity Component [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Goodwill and Intangible Assets Disclosure [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_NotesToFinancialStatementsAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Notes To Financial Statements [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Business Combination [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_IsorayMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Isoray.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_IsorayMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Isoray [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_IsorayMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Isoray [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermNotesPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Note payable, long-term portion</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermNotesPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Note payable, long-term portion</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LongTermNotesPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Note payable, net of current portion</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Depreciation, Depletion and Amortization, Nonproduction</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Depreciation, Depletion and Amortization, Nonproduction, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DepreciationAndAmortization_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Depreciation and amortization expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BuildingAndBuildingImprovementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Building and Building Improvements [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_BuildingAndBuildingImprovementsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Building Modifications [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USTreasuryAndGovernmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">US Treasury and Government [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_USTreasuryAndGovernmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Securities of U.S. Government and Government Agencies [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MaximumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Maximum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_MaximumMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Maximum [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_RangeAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Statistical Measurement [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Common stock: $0.001 par value; authorized 750,000,000 shares; issued 74,262,990 and 70,671,464 share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CommonStockValue_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Common stock: $0.001 par value; 750,000,000 shares authorized; 114,017,755 and 74,337,990 shares issued</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireOtherProductiveAssets_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Additions to other assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquireOtherProductiveAssets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Payments to Acquire Other Productive Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationSalesAndMarketingExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Amount of sales and marketing expense attributable to disposal group, including, but not limited to, discontinued operation.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationSalesAndMarketingExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group Including Discontinued Operation Sales and Marketing Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DisposalGroupIncludingDiscontinuedOperationSalesAndMarketingExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Sales and marketing</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RoyaltyMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Royalty [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquipmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Equipment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EquipmentMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Equipment [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MayTwoThousandTwentyFourPublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">May 2024 Public Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MayTwoThousandTwentyFourPublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">May Two Thousand Twenty Four Public Offering [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_MayTwoThousandTwentyFourPublicOfferingMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">May two thousand twenty four public offering.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Preferred stock, shares authorized (in shares)</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Preferred stock, shares authorized</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_CapitalImprovementsPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Capital improvements payable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_CapitalImprovementsPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Capital Improvements Payable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_CapitalImprovementsPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Capital improvements payable.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Schedule of Debt [Table Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfDebtTableTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Summary of Note Payable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_RelatedPartyTransactionLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Related Party Transaction [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityRegistrantName_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Registrant Name</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Disclosure [Text Block]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtDisclosureTextBlock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Note Payable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_Pre-FundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pre-funded Warrants [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_Pre-FundedWarrantsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Pre-funded warrants member.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Accounts payable and accrued expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accounts payable and accrued expenses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_ConsolidatedEntitiesDomain_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Consolidated Entities [Domain]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedLoss_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Available-for-Sale Securities, Unrealized Losses</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Unrealized Loss</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Measurement Frequency [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Proceeds from the ATM Agreement, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Proceeds from Issuance of Common Stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Proceeds from issuance of common stock</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityCommonStockSharesOutstanding_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Common Stock, Shares Outstanding</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DisposalGroupClassificationAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Disposal Group Classification [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OperatingLeasePrepaidRentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Operating lease prepaid rent expense.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OperatingLeasePrepaidRentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Operating Lease Prepaid Rent Expense</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OperatingLeasePrepaidRentExpense_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Base prepaid Rent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Accumulated Other Comprehensive Income (Loss), Net of Tax</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Accumulated Other Comprehensive Income (Loss), Net of Tax, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accumulated other comprehensive (loss) income</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2009/role/negatedLabel">Additions to property and equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_PaymentsToAcquirePropertyPlantAndEquipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Payments to Acquire Property, Plant, and Equipment, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Additions to property and equipment</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Total assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_Assets_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_Assets</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property, Plant and Equipment [Table]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_IncomeStatementAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Income Statement [Abstract]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_GrossProceedsFromClosingOfUnderwrittenOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Gross proceeds from closing of underwritten offering</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_GrossProceedsFromClosingOfUnderwrittenOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Gross proceeds from closing of underwritten offering</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_GrossProceedsFromClosingOfUnderwrittenOffering_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Gross proceeds from closing of underwritten offering.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_HoustonTexasMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Houston Texas [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_HoustonTexasMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Houston Texas [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_HoustonTexasMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Houston Texas.</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Diluted loss per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Earnings Per Share, Diluted</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Diluted loss per share</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ChicagoIllinoisMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Chicago Illinois [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_ChicagoIllinoisMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Chicago Illinois.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_CityAreaCode_lbl" xlink:role="http://www.xbrl.org/2003/role/label">City Area Code</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_Cesium131BusinessMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Relating to Cesium-131 Business.</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfOwnershipConsideredForWarrantExercise_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Percentage of ownership considered for warrant exercise.</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PercentageOfOwnershipConsideredForWarrantExercise_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Percentage of ownership considered for warrant exercise</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PursuantToTheEvergreenProvisionInTheAmendedAndRestatedPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Pursuant to the Evergreen Provision in the Amended and Restated Plan [Member]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_PursuantToTheEvergreenProvisionInTheAmendedAndRestatedPlanMember_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Pursuant to the "Evergreen" Provision in the Amended and Restated Plan [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_LimitedLiabilityCompanyOrLimitedPartnershipBusinessFormationDate_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Limited Liability Company or Limited Partnership, Business, Formation Date</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="srt_LitigationCaseAxis_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Litigation Case [Axis]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease, weighted average remaining term</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_StockholdersEquityNoteStockSplitConversionRatio1_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Reverse stock split, ratio</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LeaseWithBoardOfRegentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Lease with Board of Regents [Member]</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_LeaseWithBoardOfRegentsMember_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Lease with Board of Regents.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DebtSecuritiesAvailable-For-SaleAccruedInterestReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Accrued interest receivable on available-for-sale securities</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DebtSecuritiesAvailable-For-SaleAccruedInterestReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Accrued Interest, Receivable</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_DebtSecuritiesAvailable-For-SaleAccruedInterestReceivable_lbl" xlink:role="http://www.xbrl.org/2003/role/documentation">Debt securities, available-for-sale, accrued interest, receivable.</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Property and equipment, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Property and equipment, net</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Property and equipment, net</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations_lbl" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel">Cash and cash equivalents at beginning of period</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingIncomeLoss_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating loss</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Share-based compensation</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_ShareBasedCompensation_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Share-Based Payment Arrangement, Noncash Expense, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferred_lbl" xlink:role="http://www.xbrl.org/2003/role/totalLabel">Asset Acquisition, Consideration Transferred, Total</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferred_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Asset Acquisition, Consideration Transferred</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_AssetAcquisitionConsiderationTransferred_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Asset purchase price in cash</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Available-for-sale securities that were in a gross unrealized loss position for less than 12 months, fair value</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent</link:label>
          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_lbl" xlink:role="http://www.xbrl.org/2003/role/terseLabel">Operating lease, weighted average discount rate</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/verboseLabel">Noncurrent lease liability</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NotesPayable_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Note payable</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_DeferredIncomeTaxLiabilitiesNet_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Deferred Income Tax Liabilities, Net</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="catx_OfficeSpaceInSeattleWAMember_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Office Space in Seattle WA [Member]</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="dei_EntityInteractiveDataCurrent_lbl" xlink:role="http://www.xbrl.org/2003/role/label">Entity Interactive Data Current</link:label>
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          <link:label xml:lang="en-US" xlink:type="resource" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xlink:role="http://www.xbrl.org/2003/role/label">CASH FLOWS FROM OPERATING ACTIVITIES:</link:label>
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  <xsd:element id="catx_DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSoldAndEstimatedReductionOfReserve" name="DisposalGroupIncludingDiscontinuedOperationCostsOfGoodsSoldAndEstimatedReductionOfReserve" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_statement-statement-note-3-loss-per-share-antidilutive-securities-details" name="statement-statement-note-3-loss-per-share-antidilutive-securities-details" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_GTMedicalTechnologiesIncMember" name="GTMedicalTechnologiesIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_ProgramPreclinicalCoFundingOptionMember" name="ProgramPreclinicalCoFundingOptionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_EstimatedHazardousWasteRemovalLiability" name="EstimatedHazardousWasteRemovalLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_MayTwoThousandTwentyFourPublicOfferingMember" name="MayTwoThousandTwentyFourPublicOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_AccruedInterestOnHeldToMaturityInvestments" name="AccruedInterestOnHeldToMaturityInvestments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_HoustonTexasMember" name="HoustonTexasMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_LeaseWithEnergyNorthwestMember" name="LeaseWithEnergyNorthwestMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_OfficeSpaceWithUnicoPropertiesMember" name="OfficeSpaceWithUnicoPropertiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_StockholderPlaintiffSettlementsMember" name="StockholderPlaintiffSettlementsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_TheUnderwritingAgreementMember" name="TheUnderwritingAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_DebtSecuritiesAvailable-For-SaleAccruedInterestReceivable" name="DebtSecuritiesAvailable-For-SaleAccruedInterestReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_LantheusInvestmentAgreementMember" name="LantheusInvestmentAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_SharesAndWarrantsPriceDifference" name="SharesAndWarrantsPriceDifference" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="catx_DisposalGroupIncludingDiscontinuedOperationPropertyRightOfUseAssetCurrent" name="DisposalGroupIncludingDiscontinuedOperationPropertyRightOfUseAssetCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_IsorayMember" name="IsorayMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_OperatingLeasePrepaidRentExpense" name="OperatingLeasePrepaidRentExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_ProgramLicenseOptionMember" name="ProgramLicenseOptionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_IndefinitelivedIntangibleAssetsAccumulatedAmortization" name="IndefinitelivedIntangibleAssetsAccumulatedAmortization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsInPeriodFairValue" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsInPeriodFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_NetSalesBetween10And15MillionMember" name="NetSalesBetween10And15MillionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_PercentOfOutstandingShares" name="PercentOfOutstandingShares" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="catx_statement-statement-note-8-sharebased-compensation-tables" name="statement-statement-note-8-sharebased-compensation-tables" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisePrice" name="ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisePrice" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_PromissoryNoteMember" name="PromissoryNoteMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_ProceedsFromIssuanceOfCommonStockAndPre-FundedWarrantsNet" name="ProceedsFromIssuanceOfCommonStockAndPre-FundedWarrantsNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_StockIssuedDuringPeriodValueWarrantExercises" name="StockIssuedDuringPeriodValueWarrantExercises" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_MaximumAmountOfSecuritiesOfferAndSale" name="MaximumAmountOfSecuritiesOfferAndSale" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_PercentageOfIssuedAndOutstandingCapitalStock" name="PercentageOfIssuedAndOutstandingCapitalStock" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="catx_PursuantToTheEvergreenProvisionInTheAmendedAndRestatedPlanMember" name="PursuantToTheEvergreenProvisionInTheAmendedAndRestatedPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_StockIssuedDuringPeriodSharesCommonStockAndWarrants" name="StockIssuedDuringPeriodSharesCommonStockAndWarrants" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_DisposalGroupIncludingDiscontinuedOperationResearchAndDevelopmentExpense" name="DisposalGroupIncludingDiscontinuedOperationResearchAndDevelopmentExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_ViewpointMolecularTargetingIncMember" name="ViewpointMolecularTargetingIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_ProgenicsApaMember" name="ProgenicsApaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_CapitalImprovementsPayable" name="CapitalImprovementsPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_StockIssuedDuringPeriodValuePrefundedWarrantsExercised" name="StockIssuedDuringPeriodValuePrefundedWarrantsExercised" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_StockIssuedDuringPeriodSharesPrefundedWarrantsExercised" name="StockIssuedDuringPeriodSharesPrefundedWarrantsExercised" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_VmtOptionOrProgramLicenseOptionMember" name="VmtOptionOrProgramLicenseOptionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_PublicOfferingMember" name="PublicOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_UnderwrittenOfferingMember" name="UnderwrittenOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_InterestAndOtherExpense" name="InterestAndOtherExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_JanuaryTwoThousandTwentyFourPreFundedWarrantsMember" name="JanuaryTwoThousandTwentyFourPreFundedWarrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsAssumedInPeriodGross" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsAssumedInPeriodGross" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_AdjustmentsToAdditionalPaidInCapitalAssumptionOfStockOptionsAndWarrantsAtFairValue" name="AdjustmentsToAdditionalPaidInCapitalAssumptionOfStockOptionsAndWarrantsAtFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_EstimateAggregateCostOfBuildingModifications" name="EstimateAggregateCostOfBuildingModifications" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_JanuaryTwoThousandTwentyFourPublicOfferingMember" name="JanuaryTwoThousandTwentyFourPublicOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_OppenheimerCoMember" name="OppenheimerCoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_AmendedTwoThousandTwentyIncentivePlanMember" name="AmendedTwoThousandTwentyIncentivePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_March2024PrivatePlacementMember" name="March2024PrivatePlacementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_StockIssuedDuringPeriodValueWarrantsExercised" name="StockIssuedDuringPeriodValueWarrantsExercised" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_AggregateMaximumEstimateSettlementAmount" name="AggregateMaximumEstimateSettlementAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_AdjustmentsToAdditionalPaidInCapitalIssuanceOfPreFundedWarrants" name="AdjustmentsToAdditionalPaidInCapitalIssuanceOfPreFundedWarrants" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_Pre-FundedWarrantsMember" name="Pre-FundedWarrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_DebtInstrumentNumberOfPaymentInstallment" name="DebtInstrumentNumberOfPaymentInstallment" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="catx_BofASecuritiesIncMember" name="BofASecuritiesIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_DisposalGroupIncludingDiscontinuedOperationLossOnClassificationCurrent" name="DisposalGroupIncludingDiscontinuedOperationLossOnClassificationCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_OptionAgreementMember" name="OptionAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_Available-For-SaleSecuritiesMaturities" name="Available-For-SaleSecuritiesMaturities" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_DisposalGroupIncludingDiscontinuedOperationLeaseLiabilitiesCurrent" name="DisposalGroupIncludingDiscontinuedOperationLeaseLiabilitiesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_SharesIssuedPercentOfFullydilutedOutstandingCapitalStock" name="SharesIssuedPercentOfFullydilutedOutstandingCapitalStock" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_MaximumAmountOfSecuritiesOfferAndSell" name="MaximumAmountOfSecuritiesOfferAndSell" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_DisposalGroupIncludingDiscontinuedOperationSalesAndMarketingExpense" name="DisposalGroupIncludingDiscontinuedOperationSalesAndMarketingExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_RepaymentProvisions" name="RepaymentProvisions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_TwoThousandTwentySixRegisteredOfferingMember" name="TwoThousandTwentySixRegisteredOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_OfficeSpaceInSeattleWAMember" name="OfficeSpaceInSeattleWAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_EstimatedReductionOfReserveFromHazardousWasteDisposalVendor" name="EstimatedReductionOfReserveFromHazardousWasteDisposalVendor" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_RegisteredOfferingMember" name="RegisteredOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_LesseeOperatingLeaseNumberOfRenewalOptions" name="LesseeOperatingLeaseNumberOfRenewalOptions" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_NotesToFinancialStatementsAbstract" name="NotesToFinancialStatementsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_StockIssuedDuringPeriodValueCommonStockAndWarrants" name="StockIssuedDuringPeriodValueCommonStockAndWarrants" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_InvestmentAgreementContingentAmountOfGrossProceedsRaised" name="InvestmentAgreementContingentAmountOfGrossProceedsRaised" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_InvestmentAgreementsAbstract" name="InvestmentAgreementsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_SeriesBConvertiblePreferredStockMember" name="SeriesBConvertiblePreferredStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_ChinoCaliforniaMember" name="ChinoCaliforniaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_PiperSandlerAmpCoAndUBSSecuritiesLLCMember" name="PiperSandlerAmpCoAndUBSSecuritiesLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_MaximumIncreaseOrDecreaseInOwnershipPercentage" name="MaximumIncreaseOrDecreaseInOwnershipPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_SharebasedCompensationArrangementsBySharebasedPaymentAwardOptionsAssumedInPeriodWeightedAverageExercisePrice" name="SharebasedCompensationArrangementsBySharebasedPaymentAwardOptionsAssumedInPeriodWeightedAverageExercisePrice" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_NetAccretionOfDiscountsOnAvailable-For-SaleSecurities" name="NetAccretionOfDiscountsOnAvailable-For-SaleSecurities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_TwoThousandTwentySixPre-FundedWarrantsMember" name="TwoThousandTwentySixPre-FundedWarrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_Rule10B51ArrModifiedFlag" name="Rule10B51ArrModifiedFlag" type="xbrli:booleanItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_SaleOfStockMaximumCommissionPercentage" name="SaleOfStockMaximumCommissionPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="catx_RoyaltyAgreementPercentageOfNetSalesReceivable" name="RoyaltyAgreementPercentageOfNetSalesReceivable" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="catx_StockIssuedDuringSharesCommonStockWarrantExercised" name="StockIssuedDuringSharesCommonStockWarrantExercised" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_ReserveForEnvironmentalWasteDisposalReduced" name="ReserveForEnvironmentalWasteDisposalReduced" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_ProgenicsMember" name="ProgenicsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_TwoThousandTwentyFourAtMarketOfferingMember" name="TwoThousandTwentyFourAtMarketOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_NetSalesGreaterThan15MillionMember" name="NetSalesGreaterThan15MillionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_MarchTwoThousandTwentyFourInvestmentAgreementMember" name="MarchTwoThousandTwentyFourInvestmentAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_GTMedicalStockMember" name="GTMedicalStockMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_CorporateDebtSecuritiesAtCarryingValue" name="CorporateDebtSecuritiesAtCarryingValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_ChicagoIllinoisMember" name="ChicagoIllinoisMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_StockIssuedDuringPeriodSharesCommonStockWarrantExercised" name="StockIssuedDuringPeriodSharesCommonStockWarrantExercised" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_statement-statement-note-10-leases-tables" name="statement-statement-note-10-leases-tables" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_RofoOptionMember" name="RofoOptionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_NonRule10B51ArrangementModifiedFlag" name="NonRule10B51ArrangementModifiedFlag" type="xbrli:booleanItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_DisposalGroupIncludingDiscontinuedOperationAssetRetirementObligationCurrent" name="DisposalGroupIncludingDiscontinuedOperationAssetRetirementObligationCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_PercentageOfIncreaseInCommonStockCapitalSharesForFutureIssuance" name="PercentageOfIncreaseInCommonStockCapitalSharesForFutureIssuance" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_ATMAgreementMember" name="ATMAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_Cesium131BusinessMember" name="Cesium131BusinessMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_LeaseWithBoardOfRegentsMember" name="LeaseWithBoardOfRegentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_January2024PublicOfferingMember" name="January2024PublicOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_PrefundedWarrantsMember" name="PrefundedWarrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_PromissoryNoteForPurchasingLandAndBuildingMember" name="PromissoryNoteForPurchasingLandAndBuildingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_MayTwoThousandTwentyFourPreFundedWarrantsMember" name="MayTwoThousandTwentyFourPreFundedWarrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_OneTimePaymentReceivedForRightsGranted" name="OneTimePaymentReceivedForRightsGranted" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="credit"/>
  <xsd:element id="catx_GrossProceedsFromClosingOfUnderwrittenOffering" name="GrossProceedsFromClosingOfUnderwrittenOffering" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_NetSalesOf10MillionOrLessMember" name="NetSalesOf10MillionOrLessMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_LantheusAlphaTherapyLlcMember" name="LantheusAlphaTherapyLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_TwoThousandTwentySixOfferingMember" name="TwoThousandTwentySixOfferingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_ProceedsFromTheSaleOfCommonStockPursuantToAt-The-MarketOfferingNet" name="ProceedsFromTheSaleOfCommonStockPursuantToAt-The-MarketOfferingNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_OtherMember" name="OtherMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_PlacementAgentsCashFeePercentage" name="PlacementAgentsCashFeePercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="catx_InvestmentsAndAgreementsDisclosureTextBlock" name="InvestmentsAndAgreementsDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false"/>
  <xsd:element id="catx_PercentageOfOwnershipConsideredForWarrantExercise" name="PercentageOfOwnershipConsideredForWarrantExercise" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="catx_RecognitionOfOperatingLeaseLiabilityAndRightOfUseAsset" name="RecognitionOfOperatingLeaseLiabilityAndRightOfUseAsset" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="false" xbrli:balance="debit"/>
  <xsd:element id="catx_PercentageOfOwnershipConsideredForWarrantExerciseTwo" name="PercentageOfOwnershipConsideredForWarrantExerciseTwo" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" nillable="true" abstract="false"/>
  <xsd:element id="catx_CoralvilleIAMember" name="CoralvilleIAMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
  <xsd:element id="catx_May2024PreFundedWarrantsMember" name="May2024PreFundedWarrantsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" nillable="true" abstract="true"/>
</xsd:schema>
