LES ACTIVITÉS NUCLÉAIRES : RAYONNEMENTS IONISANTS ET RISQUES POUR LA SANTÉ ET L’ENVIRONNEMENT Low Dose‑Rate (LDR) brachytherapy is carried out at present using sealed sources of iodine-125 in the form of permanently implanted seeds, or caesium-137 applied temporarily. The dose rates are between 0.4 and 2 grays per hour (Gy/h). A new medical device known as “DART” (Diffusing Alpha Emitters Radio Therapy) is currently being tested as part of a clinical investigation for the treatment of cancers of the skin, oral cavity or prostate, for example. This technique consists in implanting sealed radium-224 sources which emit alpha particles in the tumour using an afterloader; the sources are left in the tumour for 15 to 20 days. Pulsed Dose‑Rate (PDR) brachytherapy delivers dose rates of between 2 and 12 Gy/h and uses sources of iridium-192 with a maximum activity of 18.5 gigabecquerels (GBq), which are applied with a specific source afterloader. It is based on the use of a single radioactive source which moves in steps, and stops in predetermined positions for predetermined times. The doses are delivered in sequences of 5 to 20 minutes, sometimes even 50 minutes, every hour for the entire duration of the treatment, hence the name pulsed dose-rate brachytherapy. High Dose‑Rate (HDR) brachytherapy is carried out using highactivity (about 370 and 91 GBq respectively) sealed sources of iridium-192 or cobalt-60. The dose rates are higher than 12 Gy/h. Positioning is done using an afterloader containing the source. The treatments are delivered on an out-patient basis, in one or more sessions of a few minutes, spread over several days if necessary. 2.2.2 – Technical rules applicable to brachytherapy facilities The rules for radioactive source management in brachytherapy are comparable to those defined for all sealed sources, regardless of their use (see point 1.3.1). In cases where permanent implant techniques are used (LDR), the applications are carried out in the operating theatre with ultrasonography monitoring, and do not require hospitalisation in a room with radiation protection. The PDR technique, which uses source afterloaders (usually 18.5 GBq of iridium-192), necessitates hospitalisation of the patient for several days in a room with radiological protection appropriate for the maximum activity of the radioactive source used. Lastly, with the HDR sources, as the maximum activity used in the source afterloaders is high (370 GBq of iridium-192 or 91 GBq of cobalt-60), the irradiations can only be carried out in a room with a configuration comparable to that of an external-beam radiotherapy room in terms of collective protection because of the high dose level used. The Order of 29 November 2019 sets the obligations concerning the protection of ionising radiation sources and batches of radioactive sources of categories A, B, C and D against malicious acts. The requirements concerning the protection barriers and their resistance time for category A, B and C sources are enforceable since 1 July 2022 (see chapter 6, point 2.3.2). As some centres could not enlarge their premises or build new bunkers, ASNR licensed two centres with “mixed-purpose” bunkers for joint external-beam radiotherapy and HDR brachytherapy practices on the basis of an expert assessment concerning the design rules for premises housing both medical linear electron accelerators and HDR source projectors. The regulatory provisions to protect high-activity sources against malicious acts have been taken into account. ASNR was particularly attentive to the analysis of the licensee’s provisions regarding the following main points: ∙organisation of the alternations between the different treatments and the quality control time slots (number of patients treated, organisation of the schedules, time slots for MD quality controls, time slots for treatments, etc.); ∙patient positioning that facilitates their evacuation in case of emergency; ∙specific safety systems preventing the simultaneous operation of two devices; ∙separate and clearly identified indicator lights and emergency stop controls for the two systems; ∙double zoning plan displayed at the entrance; ∙procedure if personnel get shut inside, for both devices. 2.2.3 – Radiation protection situation in brachytherapy ASNR has licensed 57 brachytherapy centres, 51 of which use the HDR technique. Twenty-three licences and licence renewals were issued in 2025 (see Graph 3). The number of authorised centres remained stable in 2025. However, ASNR observes that some brachytherapy centres have difficulties in maintaining certain activities due to a lack of medical personnel trained in brachytherapy techniques, even if they wish to maintain these activities in order to offer the patients the most appropriate treatments for their pathology. In addition, HDR brachytherapy treatments are still in the majority (2 PDR centres, 3 LDR centres). The INCa Observatory records 600 to 700 LDR treatments, 700 to 750 PDR treatments for gynaecological cancers and between 4,500 and 5,000 HDR treatments. In the same way as for external-beam radiotherapy, the safety of brachytherapy treatments has been a priority area of ASNR oversight since 2007, because of the intensity of the doses delivered and, where applicable, the high dose rates. As brachytherapy is carried out within radiotherapy departments, inspections are conducted on a four-year cycle and include controls similar to those performed in external beam radiotherapy (see point 2.1.3.2). Due to the use of high-activity sources, specific inspections are carried out to assess source security. These specific inspections focus on medical personnel training, such as knowledge of the action to take in the event of an emergency (source jamming), and the security of these sources (organisation in place for source management, appropriate measures to prevent unauthorised access to the sources, source inventory, protection against malicious acts and management of sensitive information). In 2025, 16 inspections were carried out on the theme of radiation protection, representing 29% of the licensed departments. 2.2.3.1 Management of sources The organisational set-ups enable the category of each source or batch of sources to be identified in 94% of the centres inspected, a level similar to that for industry as a whole and an increase compared with 2024 (80%). This is the indicator that obtains the highest score of conformity and the number of sites that have not yet classified their sources is very small. The nominative authorisations delivered by the RNA to allow access to the sources, their carriage, or access to the information relating to the means or measures that protect them raise no comments in slightly less than half the situations (44%), which is stable compared with 2024. This result is lower than that observed in the industrial sector; this regulation would in principle seem more difficult to comply with given the number of persons concerned and the nature of the medical facilities whose function is to receive the public. ASNR has nevertheless observed a few critical cases (lack of authorisation) in the medical sector. In 2025, 44% of the inspections concluded that the policy for protection against malicious acts was satisfactory, as well as the measures implemented for the identification and control of sensitive information. This is down on 2024, when 50% of establishments had a satisfactory policy, but up on 2023 and 2022. 204 ASNR Report on the state of nuclear safety and radiation protection in France in 2025
RkJQdWJsaXNoZXIy NjQ0NzU=