Handling liquid radioactive waste in radionuclide therapy

Relevance : Currently, medical liquid radioactive waste (LRW) in radionuclide therapy units (RTU) is sent via special sewerage to storage tanks, where it is kept for radioactive decay. When the established standard for specific radioactivity is reached, the accumulated LRW is discharged into the domestic sewerage system. However, if LRW contains radiopharmaceuticals with several different radionuclides, determining the optimal holding time is a complex task. Purpose : Analysis of existing and development of new technologies for the removal of LRW with a complex radionuclide composition in RTU units. Material and methods : The advantages and disadvantages of the existing technology for determining the holding time of liquid radioactive waste in a storage tank based on the results of radiometry of periodically collected samples of liquid radioactive waste are considered. It is shown that it does not meet the requirements for reducing labor intensity and ensuring radiation safety of the RTU unit personnel. Six new technologies for managing liquid radioactive waste removal are proposed, of which a technology based on a single dosimetry of γ‑radiation from a filled tank with subsequent calculation of the holding time to determine the moment of timely discharge of decayed liquid radioactive waste into the domestic sewage system is proposed for practical application. Results : Using the proposed technology, the optimal moment for discharging the contents of a tank with liquid radioactive waste accumulated in it, which are radiopharmaceuticals excreted from the body of patients labeled with radionuclides 131 I, 153 Sm, 177 Lu, is determined. Conclusion : The developed technology for the removal of liquid radioactive waste is characterized by accuracy acceptable for radiation‑hygienic purposes while ensuring simplicity and low labor intensity of its practical application in the RNT departments of domestic medical institutions.