National survey of patient doses from whole-body FDG PET-CT examinations in France in 2011

A national survey of patient doses from 'whole-body PET-CT' examinations was conducted within all French nuclear medicine departments in 2011. Data related to injected [(18)F]-fluorodeoxyglucose (FDG) activity and to computerised tomography (CT) parameters were received from 56 positron emission tomography (PET)-CT units (answer rate: ∼60 %). The average specific injected FDG activity was equal to 4.3 MBq kg(-1), in agreement with European recommendations. The new 'time-of-flight' technology enabled to decreasing the specific activity down to 3.5 MBq kg(-1). The results have shown that current diagnostic reference levels (DRLs) for the diagnostic trunk CT are too high for CT combined with PET, only performed in France for attenuation correction and localisation, and not for diagnostic purpose. Despite wide variations between PET-CT units (4-fold factor in CTDI(vol)), DRLs equal to 8 mGy (CTDI(vol)) and 750 mGy cm (dose-length product) could be proposed for whole-body PET-CT. The average effective dose related to whole-body PET-CT examination in France has been assessed to ∼14 mSv.