Development of Simple Methods to Reduce the Exposure of the Public to Radiation from Patients Who Have Undergone 18F-FDG PET/CT.

At a time when reducing the radiation dose to patients and the public has become a major focus, we assessed the radiation exposure rate from patients after an 18F-FDG PET/CT scan and evaluated different interventions to reduce it. Methods: We enrolled 100 patients, divided into 2 groups. For both groups, the radiation dose rate was measured with an ionization survey meter immediately after the scan. For group 1, the patients then voided and their dose rate was measured again. For group 2, the patients waited 30 min before voiding, and we measured the dose rate before (group 2A) and after (group 2B) they voided. Results: In total, 74 of the 100 patients exceeded the 20 µSv/h (2 mR/h) threshold immediately after the scan. In group 1, the mean dose rate decreased by 20.0% from the postscan measurement, with 12 of 36 remaining at or above 20 µSv/h. In group 2A, the mean dose rate decreased by 23% from the postscan measurement, with 9 of 38 remaining at or above 20 µSv/h. In group 2B, the mean dose rate decreased by 35% from the postscan measurement, with 1 of 38 remaining at 20 µSv/h. Conclusion: Nearly 75% of patients undergoing an 18F-FDG PET/CT scan exceed 20 µSv/h when leaving the imaging facility. The most effective method to reduce radiation exposure was to have the patient void 30 min after the examination.