Harmonization of practice of release of patients after radiopharmaceutical therapy

The implementation of novel therapeutic radiopharmaceuticals requires developing, updating, and harmonizing requirements for radiation safety in radiopharmaceutical therapy (RPT). Public exposure from patients with administered radiopharmaceuticals and biological radioactive waste management have been identified as the main problems in RPT. The aim of our study was to compare different approaches to the development of patient release criteria after RPT with different radiopharmaceuticals, considering radiation exposure of members of the public in transport, biological elimination of radionuclides from a patient's body, and the generation of biological waste. The study was performed for the following radiopharmaceuticals:¹⁷⁷Lu-PSMA-617,¹⁷⁷Lu-DOTATATE, Na¹³¹I,¹³¹I-mIBG, and¹⁵³Sm-oxabifor. Two base approaches to patient release criteria were considered. The first approach is based on the radioactive decay of radionuclides and is divided into two groups: considering one radiopharmaceutical administration and considering several radiopharmaceutical administrations per course. The second approach is based on the radioactive decay of radionuclides and biological elimination of radiopharmaceuticals from the patient's body (effective half-life) and is divided into groups based on 1 and 5 mSv dose constraints per course. The ffective dose rates from patients and sewage tanks to passengers and staff on public transport were estimated for various scenarios of patients traveling after RPT. The results demonstrated that the radiation safety of members of the public in transport should be considered when establishing the release criteria of patients after RPT. Based on the results, it is recommended to follow the approach based on the radioactive decay of radionuclides and dose constraints to members of the public in contact with patients of 1 mSv per radiopharmaceutical administration, and keep patients in the nuclear medicine department after radiopharmaceutical administration for at least 4-6 h. The patient release criteria defined according to this approach comply with patient release criteria used in different countries, and allow the radiation safety of the public to be maintained.