ASN Report 2020

methods in existing buildings. This was made possible by capitalising on examples of constructions and works, experience feedback from building professionals and the publication of French and foreign studies. ∙ The development of training courses for building professionals, as radon is now included in broader subjects, such as indoor air quality and energy renovation. 3.3  Doses received by patients In France, exposure for medical purposes represents the greatest part of the artificial exposures of the public to ionising radiation. Medical exposure has been increasing over the last 30 years or so due to the rise in the number of radiological examinations – and computed tomography examinations in particular – to the ageing of the population, and to the strategies implemented to ensure better patient care, particularly in the context of patient monitoring after cancer treatment and coronary diseases. It has been regularly reviewed by the IRSN since 2002. The average effective dose per inhabitant resulting from diagnostic radiological examinations has been evaluated at 1.53 mSv for the year 2017 (IRSN “ExPRI” study 2020) for some 85 million diagnostic procedures performed in 2017 (81.6 million in 2012), i.e. 1,187 procedures for 1,000 inhabitants per year. It is to be noted that as before, the individual exposure in 2017 is very varied. Consequently, although about 32.7% of the French population underwent at least one procedure (dental procedures excluded), half the patients received a dose of 0.1 mSv or less, 75% received 1.5 mSv or less, while the most exposed 5% of patients received a dose exceeding 18.1 mSv. Conventional radiology (55.1%), computed tomography (12.8%) and dental radiology (29.6%) account for the largest number of procedures. It is the contribution of computed tomography to the effective collective dose that remains preponderant and more significant in 2017 (75%) than in 2012 (71%), whereas that of dental radiology remains very low (0.3%). In adolescents, conventional and dental radiology procedures are the more numerous (about 1,000 procedures for 1,000 individuals in 2017). Despite their frequency in this population, conventional and dental radiology procedures represent only 0.5% of the collective dose. Lastly, it is noteworthy that: ∙ A national headcount estimated at more than 30, 000 patients was exposed to a cumulative effective dose of more than 100 mSv in 2017 due to multiple computed tomography examinations. This figure reaches 500,000 if we consider a cumulative period of 6 years. This highly exposed population seems to be increasing in size regularly and relatively rapidly since 2012. Although most people in this population are old, a quarter of them are aged under 55 years. The question of possible radiation-induced effects is therefore raised for this specific population. It is worthwhile pointing out that these patients are in all likelihood suffering from serious pathologies and that the computed tomography examinations are probably vital for their treatment. ∙ Based on a sample of 120,000 children born between 2000 and 2015, the IRSN reports that in 2015, 31.3% of the children in the sample were exposed to ionising radiation for diagnostic purposes (up by 2% compared with 2010). The average effective dose is estimated at 0.43 mSv and the median at 0.02 mSv (down for the average but equivalent for the median value). This median value varies greatly according to the age category. For infants of less than one year, it is 0.55 mSv (highest value) and between 6-10 years it is 0.012 mSv. The substantial uncertainties in these studies with regard to the average effective dose values per type of procedure must nevertheless be taken into account, which justifies the need for progress in estimating doses in the next exposure study of the general population. Particular attention is required in order to control and reduce the doses linked to medical imaging, more specifically when alternative techniques can be used for a same given indication, because the multiplication of the most heavily irradiating examinations for the same person could lead to a final effective dose value of several tens of millisieverts; at this level of exposure, certain epidemiological surveys have revealed the occurrence of radiation-induced cancers. Controlling the doses of ionising radiation delivered to persons during a medical examination remains a priority for ASN. A second plan of action was published in July 2018. This plan extends the first one (2011-2017), drawn up in collaboration with the stakeholders (institutional and professional). 3.4  Exposure of non-human species (animal and plant species) The international radiation protection system was created to protect humans against the effects of ionising radiation. Environ­ mental radioactivity is thus assessed with respect to its impact on human beings and, in the absence of any evidence to the contrary, it is today considered that the current standards guarantee the protection of other species. Protection of the environment against the radiological risk and more specifically the protection of non-human species, must however be guaranteed independently of the effects on humans. Pointing out that this objective is already incorporated in the national legislation, ASN will ensure that the impact of ionising radiation on non-human species is effectively included in the TABLE 5 Total number of procedures and associated collective effective dose for each imaging method (rounded values) in France in 2012 IMAGING METHOD PROCEDURES TOTAL COLLECTIVE EFFECTIVE DOSE: 102,198 Sv NUMBER % % Conventional radiology (dentistry excluded) 44,175,500 54.0 17.7 Dental radiology 27,616,000 33.8 0.2 Computed tomography 8,484,000 10.4 71.2 Diagnostic interventional radiology 377,000 0.5 3.1 Nuclear medicine 1,103,000 1.3 7.8 Total 81,755,500 100.0 100.0 Source: IRSN 2014. 116 ASN Report on the state of nuclear safety and radiation protection in France in 2020 01 – NUCLEAR ACTIVITIES: IONISING RADIATION AND HEALTH AND ENVIRONMENTAL RISKS