Equivalent dose rate from patients after whole-body FDG-PET/CT

Abstract Introduction 18 F-fluorodeoxyglucose PET/CT (FDG-PET/CT) is an imaging modality routinely used in oncology, hematology, as well as in infectious and inflammatory diseases. Frequently, patients and their accompanying persons may be apprehensive concerning risks of radiation exposure after performing this examination, particularly when it concerns nearby young adolescents or pregnant women. Our objective was to clearly explain about radiation protection instructions for patients after performing whole-body FDG-PET/CT based on the Equivalent Dose Rate (EDR) estimation at our nuclear medicine department. Methods We measured the dosage rates from 14 patients after undergoing whole-body FDG-PET/CT performed on two different PET/CT systems, with and without Time-of-Flight technology (TOF), in the Pitie Salpetriere–Charles Foix Hospital Group. The patients explored, using the TOF PET/CT system (group 1, n  = 7), had a FDG injected dose (FDG-ID) of 3.7 MBq/kg whereas those explored using the non-TOF PET/CT system (group 2, n  = 7) had a FDG-ID of 5 MBq/kg. Measurements of the EDR at 0.8 m (EDR-0.8 m) from the sternum were obtained immediately after PET/CT completion. Results Patients did not differ in terms of body mass index, mean ± SD 27.2 ± 7.1 kg/m 2 and 27.9 ± 8.1 kg/m 2 , for group 1 and 2 respectively. The median administrated activity was not significantly different between the two groups: 263 MBq [187–362] for group 1 and 377 MBq [228–608] for group 2. The median delay of EDR-0.8 m measurement after FDG-injection was lower for group 1 (85 min [70–118]) ( P  = 0.03). The median of EDR-0.8 m did not differ between the 2 groups, 27 μSv/h [22–42] and 34 μSv/h [28–82] for group 1 and 2 respectively as well as the EDR-8 m normalized to the FDG-ID, 0.13 μSv/h/MBq [0.07–0.15] and 0.08 μSv//h/MBq [0.06–0.15], for group 1 and 2 respectively. Conclusion The present study confirmed the low values of EDR from patients after whole-body FDG-PET/CT. This suggests that patients and their accompanying persons can be reassured about potential risks of radiation exposure after this examination and that cautionary advice is unnecessary at our Hospital Group.