ASN Report 2018

6.3  ̶  The computed tomography scanner pool 1,177 CT scanners are held in some 800 centres and covered by ASN licenses. Graph 15 opposite shows the distribution of CT scanners by geographical area covered by the ASN regional divisions and the number of license or license update applications examined in 2018 (for a total of 347). In a report published in September 2018, IRSN notes that: ∙ ∙ the average age of the CT scanner pool is 3.6 years, higher in the public sector; ∙ ∙ the average age of the CT scanners at the time of renewal is 6.1 years, higher in the public sector; ∙ ∙ 83% of the 41 CT scanners aged over 10 years are located in public sector centres. 6.4  ̶  The radiation protection situation in computed tomography The ASN regional divisions carried out 26 inspections in 2018. The conclusions of these inspections are in line with the findings of the previous years. 6.5  ̶  Events reported in conventional radiology 82 significant Radiation protection Events (ESR) in conventional radiology were reported to ASN in 2018. The majority of them concern pregnant women who were unaware of their pregnancy (59 cases, i.e. 72% of the ESRs). 171 ESRs in computed tomography were reported to ASN in 2018. They chiefly concern women unaware of their pregnancy (105 case), deficiencies in practices, such as patient identity error, wrong protocol, etc. (52 cases) and situations of worker exposure (11 cases). SUMMARY The growing number of diagnostic examinations performed using CT scanners contributes to high collective doses, as medical imaging is the leading source of artificial exposure of the public to ionising radiation. The medical justification for these procedures is still insufficiently well-founded due to the highly insufficient training of the referring doctors, and sometimes the unavailability of alternative diagnostic methods (MRI, ultrasonography). In July 2018, ASN published a second plan of action for controlling ionising radiation doses delivered to persons during medical imaging. This plan aims at reinforcing the application of justification of the procedures and optimisation of the ionising radiation doses delivered to the patients. An ESR of an unusual nature in computed tomography This ESR concerns a pregnant woman who required a computed tomography examination in an emergency situation. Due to the inappropriate utilisation of one of the CT scanner control buttons, the woman and her foetus were accidentally exposed to a radiation dose very much higher than that usually delivered in this type of examination. The utilisation of this control button did not trigger any alert signal and the radiographer did not have immediate access to the information relative to the total dose delivered. Further to this ESR, which also led to a medical devices vigilance notification to the ANSM, ASN decided to set up a national experience feedback group for medical imaging ESRs, comprising experts from the learned societies and representatives of the institutions. In this context, an operational technical sheet on the utilisation of the CT scanner control button was sent to the centres equipped with this model of scanner. Given the large number of CT scanners of this type installed in France and abroad, ASN has published and translated into English its technical recommendations and has widely distributed them, particularly through a HERCA meeting last September, where this procedure for experience feedback to the European authorities was very favourably received. ASN report on the state of nuclear safety and radiation protection in France in 2018  227 07 – MEDICAL USES OF IONISING RADIATION 07