Radiation safety problems during the patient traveling by public transport after radiopharmaceutical therapy with 131I

Radiopharmaceutical therapy with 131 I has been one of the most common types of radiopharmaceutical therapy for many years. Radiation safety of the public is ensured by limiting the patient contacts until the radiological parameters are reduced to the established criteria. To increase the availability of the radiopharmaceutical therapy with 131 I, softer patient release criteria for 131 I have been proposed. However, early patient release may increase exposure to the public, e.g. in transport. The aim of the work is to evaluate the radiation exposure from patients with 131 I -MIBG and Na 131 I on the public in transport considering the generation of biological waste. In this work, 131 I excretion from the body of patients in transport was evaluated for different scenarios of patient travel to the place of residence. As a result, it was found that mitigation of patient release criteria leads to an increase in the effective dose to the public in transport and an increase in the 131 I activity excreted with patient waste. The specific activity in the tanks of biotoilets in transport, generated after the pas -sage of a patient with injected 131 I -labeled radiopharmaceuticals, exceeds the limit value of classifying liquid waste as radioactive. To optimize radiation protection of the public, it is advisable to apply a differentiated approach to release patients after therapy with 131 I: to group non-resident patients into a separate category retaining for them the established release criterion (without mitigation) to minimize the radiation impact on the public.