The CT scanner installed base in France and recommendations for radiation protection in medical imaging

In answer to a joint request from the Directorate General for Health (DGS, Ministry of Health) and the Directorate for Social Security (DSS), IRSN used two databases for which it is responsible by regulations: SIGIS, the information and radioactive sources management system (www.irsn.fr/sources), and the application for the diagnostic reference levels management. IRSN also held hearings with associations of professionals on topics in connection with the request. This study highlights the need for change by focusing on IRSN's field of competence: radiation protection. The analysis of the French installed base of CT scanners provided the following observations: - the number of CT scanners is 1,175; - the average age of the installed base is 3.6 years; - the average age of CT scanners at the time of renewal is 6.1 years; - 83% of the 41 CT scanners over 10 years old are installed in public facilities; - dose indices drop by 20 to 30% between CT scanners installed before 2009 and those installed in 2015. IRSN considers that the average age of CT scanners at the time of renewal (from 5 to 7 years) is consistent with the current cycle of technical evolutions and does not identify any reason to modify the seven-year deadline after which the technical reimbursement is reduced. Nevertheless particular attention should be paid so that technological advances having a positive impact on doses delivered to patients can benefit the entire installed base, ensuring a homogeneous renewal of CT scanners within public and private sectors. To do so, IRSN recommends renewing, as a matter of priority, CT scanners over 10 years old and those over seven years old used in paediatrics. Failing that, IRSN recommends establishing an incentive plan for upgrading CT scanners when upgrades are likely to improve their performance in terms of dose and image quality. The hearings with health professionals and the analysis realised in the scope of this report have pointed out an increase in the number of imaging procedures and some practices potentially encouraged by the reimbursement system impacting the radiation protection of patients. This report also underlines the importance of tools contributing to the relevance of imaging procedures and raises certain issues: - Implementation of quality assurance in radiology should soon be covered by regulations; - Medical physics, radiation protection and related equipment are considered in the health establishments as cost centres; - Shared medical records and picture archiving and communication systems (PACS) available on regional networks are effective tools to avoid the redundant imaging examinations; - Teleradiology and appointment making via web site could call into question the justification for the radiological examination if these practices are not well supervised; - Paediatric medical imaging requires a specific organisation which does not seem to be correctly taken into account in the reimbursement system. IRSN thus considers that justification of imaging examinations should become a priority for the health authorities. To do so IRSN recommends: - making alternative options to X-ray imaging available and making ultrasound and magnetic resonance imaging more accessible; - improving the awareness of the various participants in the justification process; - promoting the application of the justification principle by changing the reimbursement system, which is currently based only on the fee schedule for the procedure or activity. IRSN recommends using the new regulation on quality assurance in medical imaging and on clinical audit to check the suitability of imaging procedures. On organisational aspects, IRSN recommends: - supporting, in the reimbursement system, medical physics and encouraging investment in dose management systems; - promoting the creation of multidisciplinary teams dedicated to radiation protection in imaging departments; - supervising teleradiology and appointment making via web site to ensure justification of the examinations. Moreover, the generalisation and adoption in France of shared medical records and PACS will reduce the redundancy of medical imaging examinations. IRSN recommends their coherence is ensured at the national level. Due to the specific nature of paediatric imaging, IRSN recommends promoting and highlighting good practices in radiation protection commonly implemented in this field.