<?xml version="1.0" encoding="US-ASCII"?>
<!-- DFIN New ActiveDisclosure (SM) XBRL Linkbase Document - http://www.dfinsolutions.com/ -->
<!-- Creation Date :2023-02-23T16:02:28.3764+00:00 -->
<!-- Copyright (c) 2023 Donnelly Financial Solutions, Inc. All Rights Reserved. -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/StatementBalanceSheets" xlink:href="pstv-20221231.xsd#StatementBalanceSheets" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/StatementStatementsOfOperationsAndComprehensiveLoss" xlink:href="pstv-20221231.xsd#StatementStatementsOfOperationsAndComprehensiveLoss" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/StatementStatementsOfCashFlows" xlink:href="pstv-20221231.xsd#StatementStatementsOfCashFlows" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCompositionOfCertainFinancialStatementCaptionsOtherCurrentAssetsDetails" xlink:href="pstv-20221231.xsd#Role_DisclosureCompositionOfCertainFinancialStatementCaptionsOtherCurrentAssetsDetails" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCompositionOfCertainFinancialStatementCaptionsPropertyAndEquipmentNetDetails" xlink:href="pstv-20221231.xsd#Role_DisclosureCompositionOfCertainFinancialStatementCaptionsPropertyAndEquipmentNetDetails" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCompositionOfCertainFinancialStatementCaptionsAccountsPayableAndAccruedExpensesDetails" xlink:href="pstv-20221231.xsd#Role_DisclosureCompositionOfCertainFinancialStatementCaptionsAccountsPayableAndAccruedExpensesDetails" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesSummaryOfLeaseCostsDetails" xlink:href="pstv-20221231.xsd#Role_DisclosureCommitmentsAndContingenciesSummaryOfLeaseCostsDetails" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesSummaryOfFutureMinimumAnnualLeasePaymentsUnderOperatingAndFinancingLeasesDetails" xlink:href="pstv-20221231.xsd#Role_DisclosureCommitmentsAndContingenciesSummaryOfFutureMinimumAnnualLeasePaymentsUnderOperatingAndFinancingLeasesDetails" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureTermLoanObligationsFuturePaymentsUnderObligationDetails" xlink:href="pstv-20221231.xsd#Role_DisclosureTermLoanObligationsFuturePaymentsUnderObligationDetails" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureTermLoanObligationsFaceValueToBookValueReconciliationDetails" xlink:href="pstv-20221231.xsd#Role_DisclosureTermLoanObligationsFaceValueToBookValueReconciliationDetails" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesSummaryOfFutureMinimumAnnualLeasePaymentsUnderOperatingAndFinancingLeasesDetails2" xlink:href="pstv-20221231.xsd#Role_DisclosureCommitmentsAndContingenciesSummaryOfFutureMinimumAnnualLeasePaymentsUnderOperatingAndFinancingLeasesDetails2" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesReconciliationOfTotalIncomeTaxProvisionDetails" xlink:href="pstv-20221231.xsd#Role_DisclosureIncomeTaxesReconciliationOfTotalIncomeTaxProvisionDetails" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails" xlink:href="pstv-20221231.xsd#Role_DisclosureIncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails" xlink:type="simple"/>
  <link:roleRef roleURI="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureTermLoanObligationsFaceValueToBookValueReconciliationDetails2" xlink:href="pstv-20221231.xsd#Role_DisclosureTermLoanObligationsFaceValueToBookValueReconciliationDetails2" xlink:type="simple"/>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/StatementBalanceSheets">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_Liabilities" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_LiabilitiesCurrent" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_AssetsCurrent" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_PreferredStockValue" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_CommitmentsAndContingencies" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent" xlink:to="us-gaap_OtherAssetsCurrent" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_PropertyPlantAndEquipmentNet" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_CommonStockValue" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_StockholdersEquity" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent" xlink:to="us-gaap_LongTermDebtCurrent" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_LongTermDebtNoncurrent" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_OperatingLeaseRightOfUseAsset" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_AdditionalPaidInCapital" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_DeferredIncomeNoncurrent" order="3" weight="1" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_Goodwill" order="3" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit" order="3" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_WarrantsAndRightsOutstanding" order="4" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_OtherIntangibleAssetsNet" order="4" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_OtherAssetsNoncurrent" order="5" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsCurrent" xlink:label="us-gaap_AssetsCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PreferredStockValue" xlink:label="us-gaap_PreferredStockValue"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="us-gaap_CommitmentsAndContingencies"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsCurrent" xlink:label="us-gaap_OtherAssetsCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtCurrent" xlink:label="us-gaap_LongTermDebtCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="us-gaap_LongTermDebtNoncurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="us-gaap_AdditionalPaidInCapital"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredIncomeNoncurrent" xlink:label="us-gaap_DeferredIncomeNoncurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WarrantsAndRightsOutstanding" xlink:label="us-gaap_WarrantsAndRightsOutstanding"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherIntangibleAssetsNet" xlink:label="us-gaap_OtherIntangibleAssetsNet"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="us-gaap_OtherAssetsNoncurrent"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/StatementStatementsOfOperationsAndComprehensiveLoss">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_Revenues" order="0" weight="1" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_InvestmentIncomeInterest" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_OperatingIncomeLoss" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_ResearchAndDevelopmentInProcess" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_InterestExpense" order="1" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_NonoperatingIncomeExpense" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss" xlink:to="us-gaap_OperatingExpenses" order="2" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_GeneralAndAdministrativeExpense" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NonoperatingIncomeExpense" xlink:to="us-gaap_LiabilitiesFairValueAdjustment" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_GainLossOnDispositionOfAssets" order="3" weight="-1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Revenues" xlink:label="us-gaap_Revenues"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingExpenses" xlink:label="us-gaap_OperatingExpenses"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost" xlink:label="us-gaap_ResearchAndDevelopmentExpenseExcludingAcquiredInProcessCost"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="us-gaap_NonoperatingIncomeExpense"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentIncomeInterest" xlink:label="us-gaap_InvestmentIncomeInterest"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentInProcess" xlink:label="us-gaap_ResearchAndDevelopmentInProcess"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestExpense" xlink:label="us-gaap_InterestExpense"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="us-gaap_GeneralAndAdministrativeExpense"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesFairValueAdjustment" xlink:label="us-gaap_LiabilitiesFairValueAdjustment"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GainLossOnDispositionOfAssets" xlink:label="us-gaap_GainLossOnDispositionOfAssets"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/StatementStatementsOfCashFlows">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_RepaymentsOfLongTermDebt" order="0" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_NetIncomeLoss" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="pstv_PaymentsToAcquirePropertyPlantAndEquipmentAndIntangibleAssets" order="0" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_FinanceLeasePrincipalPayments" order="1" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_DepreciationDepletionAndAmortization" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="pstv_ProceedsFromWarrantExercises1" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_AmortizationOfFinancingCostsAndDiscounts" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock" order="3" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_ResearchAndDevelopmentInProcess" order="3" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="pstv_CashPaidForIPRDAssetAcquiredInAnAssetAcquisition" order="3" weight="-1" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_FairValueAdjustmentOfWarrants" order="4" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_GainLossOnDispositionOfAssets" order="5" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_ShareBasedCompensation" order="6" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" order="7" weight="1" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_IncreaseDecreaseInOtherCurrentAssets" order="10" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_IncreaseDecreaseInOperatingLeaseLiability" order="11" weight="1" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities" order="12" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" order="14" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="us-gaap_RepaymentsOfLongTermDebt"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_PaymentsToAcquirePropertyPlantAndEquipmentAndIntangibleAssets" xlink:label="pstv_PaymentsToAcquirePropertyPlantAndEquipmentAndIntangibleAssets"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeasePrincipalPayments" xlink:label="us-gaap_FinanceLeasePrincipalPayments"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="us-gaap_DepreciationDepletionAndAmortization"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:label="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_ProceedsFromWarrantExercises1" xlink:label="pstv_ProceedsFromWarrantExercises1"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:label="us-gaap_AmortizationOfFinancingCostsAndDiscounts"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentInProcess" xlink:label="us-gaap_ResearchAndDevelopmentInProcess"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_CashPaidForIPRDAssetAcquiredInAnAssetAcquisition" xlink:label="pstv_CashPaidForIPRDAssetAcquiredInAnAssetAcquisition"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAdjustmentOfWarrants" xlink:label="us-gaap_FairValueAdjustmentOfWarrants"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GainLossOnDispositionOfAssets" xlink:label="us-gaap_GainLossOnDispositionOfAssets"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" xlink:label="us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOtherCurrentAssets" xlink:label="us-gaap_IncreaseDecreaseInOtherCurrentAssets"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:label="us-gaap_IncreaseDecreaseInOperatingLeaseLiability"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities" xlink:label="us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCompositionOfCertainFinancialStatementCaptionsOtherCurrentAssetsDetails">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherAssetsCurrent" xlink:to="us-gaap_OtherPrepaidExpenseCurrent" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherAssetsCurrent" xlink:to="us-gaap_PrepaidInsurance" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OtherAssetsCurrent" xlink:to="pstv_Other" order="2" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsCurrent" xlink:label="us-gaap_OtherAssetsCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherPrepaidExpenseCurrent" xlink:label="us-gaap_OtherPrepaidExpenseCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PrepaidInsurance" xlink:label="us-gaap_PrepaidInsurance"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_Other" xlink:label="pstv_Other"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCompositionOfCertainFinancialStatementCaptionsPropertyAndEquipmentNetDetails">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_PropertyPlantAndEquipmentGross" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PropertyPlantAndEquipmentGross" xlink:to="pstv_OfficeAndComputerEquipmentGross" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" order="1" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PropertyPlantAndEquipmentGross" xlink:to="us-gaap_LeaseholdImprovementsGross" order="1" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_OfficeAndComputerEquipmentGross" xlink:label="pstv_OfficeAndComputerEquipmentGross"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseholdImprovementsGross" xlink:label="us-gaap_LeaseholdImprovementsGross"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCompositionOfCertainFinancialStatementCaptionsAccountsPayableAndAccruedExpensesDetails">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="us-gaap_AccountsPayableCurrent" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="us-gaap_AccruedBonusesCurrent" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="us-gaap_AccruedProfessionalFeesCurrent" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="pstv_AccruedVacationAndCompensationCurrent" order="3" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="us-gaap_FinanceLeaseLiability" order="4" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="us-gaap_OtherLiabilitiesCurrent" order="5" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="pstv_AccruedResearchAndDevelopmentStudies" order="6" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsPayableCurrent" xlink:label="us-gaap_AccountsPayableCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedBonusesCurrent" xlink:label="us-gaap_AccruedBonusesCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedProfessionalFeesCurrent" xlink:label="us-gaap_AccruedProfessionalFeesCurrent"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_AccruedVacationAndCompensationCurrent" xlink:label="pstv_AccruedVacationAndCompensationCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeaseLiability" xlink:label="us-gaap_FinanceLeaseLiability"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:label="us-gaap_OtherLiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_AccruedResearchAndDevelopmentStudies" xlink:label="pstv_AccruedResearchAndDevelopmentStudies"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesSummaryOfLeaseCostsDetails">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="pstv_CashPaidForAmountsIncludedInMeasurementOfLeaseLiabilities" xlink:to="us-gaap_OperatingLeasePayments" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LeaseCost" xlink:to="us-gaap_OperatingLeaseCost" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="pstv_CashPaidForAmountsIncludedInMeasurementOfLeaseLiabilities" xlink:to="us-gaap_FinanceLeasePrincipalPayments" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LeaseCost" xlink:to="us-gaap_FinanceLeaseRightOfUseAssetAmortization" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LeaseCost" xlink:to="us-gaap_FinanceLeaseInterestExpense" order="2" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_CashPaidForAmountsIncludedInMeasurementOfLeaseLiabilities" xlink:label="pstv_CashPaidForAmountsIncludedInMeasurementOfLeaseLiabilities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeasePayments" xlink:label="us-gaap_OperatingLeasePayments"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseCost" xlink:label="us-gaap_LeaseCost"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseCost" xlink:label="us-gaap_OperatingLeaseCost"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeasePrincipalPayments" xlink:label="us-gaap_FinanceLeasePrincipalPayments"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeaseRightOfUseAssetAmortization" xlink:label="us-gaap_FinanceLeaseRightOfUseAssetAmortization"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinanceLeaseInterestExpense" xlink:label="us-gaap_FinanceLeaseInterestExpense"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesSummaryOfFutureMinimumAnnualLeasePaymentsUnderOperatingAndFinancingLeasesDetails">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingLeaseLiability" xlink:to="us-gaap_OperatingLeaseLiabilityCurrent" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingLeaseLiability" xlink:to="us-gaap_OperatingLeaseLiabilityNoncurrent" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="pstv_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" order="4" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiability" xlink:label="us-gaap_OperatingLeaseLiability"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" xlink:label="pstv_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureTermLoanObligationsFuturePaymentsUnderObligationDetails">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ContractualObligation" xlink:to="us-gaap_ContractualObligationDueInNextTwelveMonths" order="0" weight="1" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ContractualObligation" xlink:to="us-gaap_ContractualObligationDueInSecondYear" order="1" weight="1" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractualObligation" xlink:label="us-gaap_ContractualObligation"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractualObligationDueInNextTwelveMonths" xlink:label="us-gaap_ContractualObligationDueInNextTwelveMonths"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractualObligationDueInSecondYear" xlink:label="us-gaap_ContractualObligationDueInSecondYear"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureTermLoanObligationsFaceValueToBookValueReconciliationDetails">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:to="us-gaap_ContractualObligation" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:to="us-gaap_DebtInstrumentUnamortizedDiscount" order="1" weight="-1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:label="us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractualObligation" xlink:label="us-gaap_ContractualObligation"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesSummaryOfFutureMinimumAnnualLeasePaymentsUnderOperatingAndFinancingLeasesDetails2">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="us-gaap_OperatingLeaseLiability" order="1" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:label="us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiability" xlink:label="us-gaap_OperatingLeaseLiability"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesReconciliationOfTotalIncomeTaxProvisionDetails">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" order="0" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" order="3" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="pstv_EffectiveIncomeTaxRateReconciliationNetOperatingLossExpiration" order="4" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsResearch" order="5" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="pstv_EffectiveIncomeTaxRateReconciliationTaxReturnToProvision" order="6" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationTaxSettlementsStateAndLocal" order="7" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_EffectiveIncomeTaxRateReconciliationNetOperatingLossExpiration" xlink:label="pstv_EffectiveIncomeTaxRateReconciliationNetOperatingLossExpiration"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsResearch" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsResearch"/>
    <link:loc xlink:type="locator" xlink:href="pstv-20221231.xsd#pstv_EffectiveIncomeTaxRateReconciliationTaxReturnToProvision" xlink:label="pstv_EffectiveIncomeTaxRateReconciliationTaxReturnToProvision"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationTaxSettlementsStateAndLocal" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationTaxSettlementsStateAndLocal"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureIncomeTaxesDeferredTaxAssetsAndLiabilitiesDetails">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxLiabilities" xlink:to="us-gaap_DeferredTaxAssetsNet" order="0" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsNet" xlink:to="us-gaap_DeferredTaxAssetsGross" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredIncomeTaxLiabilities" xlink:to="us-gaap_DeferredTaxLiabilitiesOther" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxLiabilities" xlink:to="us-gaap_DeferredIncomeTaxLiabilities" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" order="1" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsNet" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance" order="1" weight="-1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross" xlink:to="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" order="2" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross" xlink:to="us-gaap_DeferredTaxAssetsTaxCreditCarryforwards" order="3" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross" xlink:to="us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment" order="4" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross" xlink:to="us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets" order="5" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross" xlink:to="us-gaap_DeferredTaxAssetsOther" order="6" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxLiabilities" xlink:label="us-gaap_DeferredTaxLiabilities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsNet" xlink:label="us-gaap_DeferredTaxAssetsNet"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsGross" xlink:label="us-gaap_DeferredTaxAssetsGross"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredIncomeTaxLiabilities" xlink:label="us-gaap_DeferredIncomeTaxLiabilities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxLiabilitiesOther" xlink:label="us-gaap_DeferredTaxLiabilitiesOther"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwards"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwards" xlink:label="us-gaap_DeferredTaxAssetsTaxCreditCarryforwards"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment" xlink:label="us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets" xlink:label="us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsOther" xlink:label="us-gaap_DeferredTaxAssetsOther"/>
  </link:calculationLink>
  <link:calculationLink xlink:type="extended" xlink:role="http://www.plustherapeutics.com/20221231/taxonomy/role/Role_DisclosureTermLoanObligationsFaceValueToBookValueReconciliationDetails2">
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:to="us-gaap_LongTermDebtCurrent" order="0" weight="1.00" use="optional"/>
    <link:calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:to="us-gaap_LongTermDebtNoncurrent" order="1" weight="1.00" use="optional"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities" xlink:label="us-gaap_LongTermDebtAndCapitalLeaseObligationsIncludingCurrentMaturities"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtCurrent" xlink:label="us-gaap_LongTermDebtCurrent"/>
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="us-gaap_LongTermDebtNoncurrent"/>
  </link:calculationLink>
</link:linkbase>
