ASN Report 2020

at the end of their path, combined with a lesser effect on the tissues they pass through before reaching the target volume. 2.2  Technical rules applicable to external‑beam radiotherapy installations The devices must be installed in rooms specially designed to guarantee radiation protection of the staff, turning them into veritable bunkers (wall thickness can vary from 1 metre (m) to 2.5 m of ordinary concrete). A radiotherapy installation comprises a treatment room including a technical area containing the treatment device, a control station outside the room and, for some accelerators, auxiliary technical premises. The protection of the premises, in particular the treatment room, must be determined in order to respect the annual exposure limits for the workers and/or the public around the premises. A specific study must be carried out for each installation by the machine supplier, together with the medical physicist and the Radiation Protection Expert-Officer (RPE-O). This study defines the thicknesses and nature of the various protections required, which are determined according to the conditions of use of the device, the characteristics of the radiation beam and the use of the adjacent rooms, including those vertically above and below the treatment room. This study must be included in the file submitted to ASN to support the application for a license to use a radiotherapy installation. In addition, a set of safety systems informs the operator of the machine operating status (exposure in progress or not) and switches off the beam in an emergency or if the door to the irradiation room is opened. In 2019, ASN asked the IRSN to assess the current design requirements for premises housing external-beam radiotherapy facilities, particularly the bunker with shielding baffle. This latter design remains the reference insofar as it reduces the shielding required at the ventilation duct and electrical duct inlets and provides greater security in the event of failure of the door motorisation system or if anyone gets accidentally locked inside. However, if the space available to the licensee is limited, which compromises the installation of the accelerator, a smaller shielding baffle, or even none at all, can be envisaged under certain restrictive conditions. A new medical device named ZAP‑X® is currently undergoing the CE marking procedure. It is intended for “radiosurgery” type intracranial irradiation. The innovative feature put forward by the manufacturer is the self-shielding of this accelerator which, it is claimed, does need to be installed in a bunker. This device has been presented to the Canpri, and further information is awaited, primarily concerning radiation protection of the medical professionals. This device shall also undergo an assessment by the HAS. 2.3  Radiation protection situation in external-beam radiotherapy The safety of radiotherapy treatments has been a priority area of ASN oversight since 2007. An inspection programme has been defined for the 2020‑2023 period, and its themes have been communicated to the learned societies and government departments concerned. The inspections focus on the ability of the centres to deploy a risk management approach and, depending on the situation found by the inspectors, they also address the management of skills, the implementation of new techniques or practices and the command of the equipment. ASN has continued its graded approach to inspection: ∙ by reducing, in the light of the progress made in the control of treatment safety, the average frequency of inspection, which since 2016 has been reduced to once every four years (instead of the previous three-yearly frequency); ∙ by maintaining a higher frequency for the centres displaying vulnerabilities or risks, especially certain centres having required tightened inspections (Lucien Neuwirth Cancerology Institute in Saint‑Priest‑en‑Jarez, the Peupliers Private Hospital in Paris) and the continuation of the tightened monitoring of the Private Radiotherapy Centre of Metz (CPRM), renamed the Private Institute of Radiotherapy of Metz (IPRM) during 2019, following a change of ownership. The inspection programme was severely impacted in 2020 by the health crisis linked to the Covid‑19 pandemic. ASN adapted its oversight in order to be able to continue conducting certain high-stake inspections on site. The other inspections were carried out remotely or postponed until 2021. As a result, ASN carried out 49 of the 73 inspections initially scheduled in 2020, representing 28% of the national installed base. In comparison, 73 inspections were carried out in 2019, representing 42% of the national installed base. Thirteen of the inspections carried out in 2020 were conducted entirely remotely. 2.3.1 Radiation protection of external-beam radiotherapy professionals When the radiotherapy facilities are correctly designed, the radiation risks for the medical staff are limited due to the protection provided by the walls of the irradiation room. The results of the inspections carried out in 2020 reveal no major problems in this sector: ∙ The effective designation of Radiation Protection Advisors (RPA) was confirmed in the majority of the centres inspected. ∙ The radiation protection technical controls were carried out in about 90% of the centres inspected and were satisfactory. 2.3.2 Radiation protection of radiotherapy patients The assessment of the radiation protection of radiotherapy patients is based on the inspections focusing on implementation of the treatment quality and safety management system, made compulsory by ASN resolution 2008-DC-0103 of 1 July 2008. Since 2016, these inspections have included verifications of the adequacy of the human resources, and in particular the presence of the medical physicist and internal organisation procedures for tracking and analysing adverse events – or malfunctions – recorded by the radiotherapy centres. The presence of a medical physicist during the treatments was confirmed in 100% of the inspected centres. All the centres have a medical physics organisation plan, but the quality of the plans vary from one centre to another. The detection of adverse events, their reporting (internally or to ASN) and their recording are deemed satisfactory on the whole. In addition, significant progress is observed in the analysis of these adverse events, the defining of corrective actions and the lessons learned from them: they are satisfactory in 66% of the inspections, compared with 46% in 2019 (see Graph 6). The improvement in practices through experience feedback and the assessment of the effectiveness of the corrective actions were deemed satisfactory in only 38% of the centres inspected (see Graph 6). This is nevertheless an improvement on 2019, where this proportion was just 27%. In order to be effective, these approaches must bring together representatives of all the professionals involved in the delivery of treatments. The lack of availability of personnel, especially medical, limits their effectiveness. ASN Report on the state of nuclear safety and radiation protection in France in 2020 215 07 – MEDICAL USES OF IONISING RADIATION 07