Four sets of correction factors needed to apply the new small field dosimetry formalism are provided for several active detectors. A protocol for small photon beams OF determination based on passive dosimeters measurements has been recently proposed to French radiotherapy treatment centers.

After 5 y of collecting data on diagnostic reference levels (DRLs), the Nuclear Safety and Radiation Protection French Institute (IRSN) presents the analyses of this data. The analyses of the collected data for radiology, computed tomography (CT) and nuclear medicine allow IRSN to estimate the level of regulatory application by health professionals and the representativeness of current DRL in terms of relevant examinations, dosimetric quantities, numerical values and patient morphologies. Since 2004, the involvement of professionals has highly increased, especially in nuclear medicine, followed by CT and then by radiology. Analyses show some discordance between regulatory examinations and clinical practice. Some of the dosimetric quantities used for the DRL setting are insufficient or not relevant enough, and some numerical values should also be reviewed. On the basis of these findings, IRSN formulates recommendations to update regulatory DRL with current and relevant examination lists, dosimetric quantities and numerical values.

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.

Based on these findings, IRSN recommends to update DRL regulation with current and relevant examination lists, dosimetric quantities and numerical values. In addition, this study shows that technology and generation of equipment, such as detector type in radiography or image reconstruction algorithm in CT, take an important place in the dose optimisation process, enabling significant patient exposure reduction when it is associated with protocols optimisation.

The Nuclear Safety and Radiation Protection French Institute (IRSN) presents its latest assessment from up-to-date diagnostic reference levels (DRL) national data in nuclear medicine (NM). NM departments annually send data to IRSN to estimate the representativeness of current DRLs. Complementary analyses of the data have been performed to evaluate the influence of equipment evolution on practice and patient radiation exposure. Based on data from almost 90% of the French NM departments, some DRL update are proposed. The analysis of positron emission tomography data show that the more the time of flight technology is available on equipment, the lower is the administered activity to the patient. IRSN recommends updating DRL regulation with current and relevant examination data. The influence of technology evolution appeared to be positive for patient exposure and the results showed an obvious involvement of professionals in the radiation dose optimisation process.