Technical note: Quantifying radionuclide residues in hospital wastewater: A case study on 131II and 177mLuLu/177LuLu

Historically, [131I]I has been a common isotope in radionuclide therapy, with [177Lu]Lu-labelled radiopharmaceuticals now seeing a surge in use. These can include no-carrier-added or carrier-added [177Lu]Lu with slight impurities of [177mLu]Lu with a significantly longer half-life than [131I]I. Wast...

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Published in:Medical physics (Lancaster) 2024-06
Main Authors: Kupitz, Dennis, Einspänner, Eric, Wissel, Heiko, Volk, Martin, Hohn, Alexander, Kreissl, Michael C, Grosser, Oliver S
Format: Article
Language:English
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Summary:Historically, [131I]I has been a common isotope in radionuclide therapy, with [177Lu]Lu-labelled radiopharmaceuticals now seeing a surge in use. These can include no-carrier-added or carrier-added [177Lu]Lu with slight impurities of [177mLu]Lu with a significantly longer half-life than [131I]I. Wastewater from therapy wards can contain a mixture of these radioisotopes. In some countries, national regulations require wastewater to be stored in dedicated systems before it is discharged into the public sewage system. To fulfill legal requirements, the nuclide specific activity concentration must be verified.BACKGROUNDHistorically, [131I]I has been a common isotope in radionuclide therapy, with [177Lu]Lu-labelled radiopharmaceuticals now seeing a surge in use. These can include no-carrier-added or carrier-added [177Lu]Lu with slight impurities of [177mLu]Lu with a significantly longer half-life than [131I]I. Wastewater from therapy wards can contain a mixture of these radioisotopes. In some countries, national regulations require wastewater to be stored in dedicated systems before it is discharged into the public sewage system. To fulfill legal requirements, the nuclide specific activity concentration must be verified.We evaluate a method for determining the activity concentration of [177mLu]Lu /[177Lu]Lu at equilibrium and [131I]I in pure and mixed samples in order to prove that the determined values are reliably below the limits for release.PURPOSEWe evaluate a method for determining the activity concentration of [177mLu]Lu /[177Lu]Lu at equilibrium and [131I]I in pure and mixed samples in order to prove that the determined values are reliably below the limits for release.We analysed the emitted energy spectrum of 1 L samples with a wastewater counter using an energy window-based approach by evaluating measurements from two different time points. Based on the law of decay and the time and energy-dependent measured values, equation systems were set up to calculate the count rates for [131I]I and [177mLu]Lu, which were converted into activity concentration using calibration factors.METHODSWe analysed the emitted energy spectrum of 1 L samples with a wastewater counter using an energy window-based approach by evaluating measurements from two different time points. Based on the law of decay and the time and energy-dependent measured values, equation systems were set up to calculate the count rates for [131I]I and [177mLu]Lu, which were converted into activity co
ISSN:2473-4209
2473-4209
DOI:10.1002/mp.17272