Analysis of data relative to the update of diagnostic reference levels in radiology and nuclear medicine. 2011-2012 review

Applying the Order of 24 October 2011 on diagnostic reference levels, departments of radiology and nuclear medicine must send a sample of 'patient' dosimetric data to the IRSN each year. The results of the analysis of dosimetric data performed between the 1 January 2011 and the 31 December 2012 presented in this report should enable the authority to define the needs for updating regulations. Professional involvement in DRLs improved globally over the 2011-2012 period but is heterogeneous according to the imaging area considered. The participation of conventional radiology professionals is still low, with less than 30% against over 75% in CT and 85% in nuclear medicine. Data collection in pediatrics, considering all the fields of medical imaging, remains extremely limited. This shows almost no dose assessment for children by imaging departments, and has the effect of not allowing authorities to provide professionals with DRLs representative of pediatric practices. The analysis of radiology doses and nuclear medicine administered activities by IRSN shows an overall decrease of statistical indicators on which DRLs are indexed. These results lead to proposals for updating reference values for a large number of examinations. In addition to the analysis of data collected for examinations currently mentioned in regulatory texts, IRSN recommends to update DRLs in a more general way by changing the strategy for collecting and updating pediatric DRLs, by including interventional radiology - specialty in which the radiation protection presents a major challenge - by introducing a more ambitious indicator than the 75. percentile in conventional radiology and nuclear medicine - the 25. percentile statistical indicator, and by taking into account new technologies inducing additional exposures to the patient as CT-scan associated with the PET. (authors)