How much do 68Ga-, 177Lu- and 131I-based radiopharmaceuticals contribute to the global radiation exposure of nuclear medicine staff?

Background The radiation exposure of nuclear medicine personnel, especially concerning extremity doses, has been a significant focus over the past two decades. This study addresses the evolving practice of NM, particularly with the rise of radionuclide therapy and theranostic procedures, which involve a variety of radionuclides such as 68 Ga, 177 Lu, and 131 I. Traditional studies have concentrated on common radioisotopes like 99m Tc, 18 F, and 90 Y, but there is limited data on these radionuclides, which are more and more frequently used. This study, part of the European SINFONIA project, aims to fill this gap by providing new dosimetry data through a multicenter approach. The research monitors extremity doses to hands, eye lens doses, and whole-body doses in nuclear medicine staff handling 68 Ga, 177 Lu, and 131 I. It examines the type of activities performed and the protective measures used. The study extrapolates measured doses to annual doses, comparing them with annual dose limits, and assesses the contribution of these specific procedures to the overall occupational dose of nuclear medicine personnel. Results Measurements were conducted from November 2020 to August 2023 across nine hospitals. The highest whole-body, eye lens and extremity doses were observed for 68 Ga. Average maximum extremity doses, normalized per manipulated activity, were found of 6200 µSv/GBq, 30 µSv/GBq and 260 µSV/GBq for 68 Ga, 177 Lu and 131 I, respectively. Average whole-body doses stayed below 60 µSv/GBq for all 3 isotopes and below 200 µSv/GBq for the eye lens dose. The variation in doses also depends on the task performed. For 68 Ga there is a risk of reaching the annual dose limit for skin dose during synthesis and dispensing. Conclusions This study’s measurement campaigns across various European countries have provided new and extensive occupational dosimetry data for nuclear medicine staff handling 68 Ga, 177 Lu and 131 I radiopharmaceuticals. The results indicate that 68 Ga contributes significantly to the global occupational dose, despite its relatively low usage compared to other isotopes. Staff working in radiopharmacy hot labs, labeling and dispensing 177 Lu contribute less to the finger dose compared to other isotopes.