Maintenance of the afterloaders (for HDR and PDR applications) – This is ensured by the manufacturers, particularly when replacing sources. The brachytherapy departments rely on these verifications to guarantee correct operation of the devices. The source activity is verified at each delivery, and verifications are also carried out on source removal. ASN notes that the verifications performed by the departments can sometimes prove insufficient when a new device is received, and draws attention to the need to clearly define these verifications taking into account the manufacturer’s requirements, particularly for HDR brachytherapy. As the doses delivered at each brachytherapy session are about 4 to 10 Gy, errors in treatment delivery can have serious consequences for the health of the patient. 2.2.3.6 Significant events notified in brachytherapy In 2024, 11 ESRs were notified in brachytherapy, 8 of which were under criterion 2.1 (exposure of patients for therapeutic purposes). Six are rated level 1 and two rated level 0 on the ASN-SFRO scale. One ESR in brachytherapy notified by several healthcare centres in 2023 and early 2024, rated level 1 on the ASN‑SFRO scale, concerned a cohort of patients in three different centres. The event was notified after the manufacturer informed the centres of a value rounding error in the software causing inaccuracy in the space between the computed tomography sections imported for the dosimetric planning of treatments. This event also led to a medical device vigilance notification to the ANSM. This inaccuracy could have resulted in a dose error of about 5 to 10% on each brachytherapy treatment fraction in certain conditions of use. The manufacturer proposed corrective measures involving the software parameter settings. In one of the centres which made its report in 2024, 136 patients were concerned, i.e. nearly half the cases in the cohort, and all the medical files were verified in order to calculate the errors in dose delivered to the target volumes, which were less than 5%. This centre decided to change the HDR afterloader. One event concerned the loss of a container of iodine-125 seeds. After treating a prostate cancer patient by brachytherapy in the operating theatre, one of two unused containers of iodine seeds could not be found. This treatment consists in placing radioactive seeds of iodine-125 in the patient’s prostate gland to irradiate the zone of the tumour. The iodine-125 seeds ordered for an intervention are not always implanted in their totality. The iodine-125 seeds not used are recovered to be returned to the supplier in a lead-lined steel container. At the end of the intervention of 1 October 2024, the box holding a container of a cartridge of 15 iodine-125 seeds that were not used for the treatment was disposed of via the domestic waste channel. This ESR illustrates the importance of having full knowledge of the management and traceability procedures for unused sources. Considering the failure of the monitoring provisions that resulted in the loss of this radioactive source, ASN rated the event level 1 on the INES scale (International Nuclear and Radiological Event Scale, graded from 0 to 7 in increasing order of severity). SUMMARY In brachytherapy, the inspections carried out in 2024 in nearly a quarter of the departments, considered alongside those carried out over the 2021-2024 period, enabling all the departments to be covered, confirm that the radiation protection rules are properly applied. ASN observes in 2024 that the gradual deployment of the new requirements relative to the protection of high-activity sources against malicious acts is continuing, particularly as regards putting in place a protection policy, measures for preventing unauthorised access to these sources and the identification and control of sensitive information. This situation is gradually improving but cannot yet be considered compliant. Some centres are still faced with difficulties when bringing into compliance necessitates major works. Moreover, ASN observes that the procedures for learning lessons from malfunctions are progressing and draws the departments’ attention to the need to have full knowledge of the management and traceability procedures for surplus iodine-125 seeds not used in prostate gland brachytherapy treatments. Lastly, maintaining a brachytherapy activity still represents a challenge for the years to come given the resources and skill that will be required. 2.3 Nuclear medicine Nuclear medicine is a medical discipline that uses radionuclides in unsealed sources for diagnostic purposes (functional imaging in vivo or medical biology in vitro) or therapeutic purposes (ITR). Thanks to the increase in new radionuclides and vectors, nuclear medicine has developed strongly over the last few years, for diagnostic and therapeutic purposes alike. Furthermore, the reform of healthcare licences (see point 1.3.3) has introduced two licensing “levels” for nuclear medicine (levels A and B) in application of Decree 2021-1930 concerning the conditions of installation of nuclear medicine departments. Level A concerns the diagnostic or therapeutic activities other than the treatment of cancerous pathologies, carried out by administering RPDs that are ready to use or are prepared using an aseptic process in a closed system. Level B is attributed when the activity includes, in addition to the procedures covered by level A, the following procedures: ∙procedures with the administration of an RPD prepared using an aseptic process in an open environment; ∙diagnostic procedures carried out for explorations of cellular marking (labelling) of the formed elements of the blood by one or more radionuclides; ∙therapeutic procedures carried by the administration of active implantable MDs; ∙therapeutic procedures for cancerous pathologies performed by administering RPDs. The healthcare activity licence for nuclear medicine is now granted by geographical site on condition that the provisions concerning the number of Single Photon Emission Computed Tomography (SPECT) and PET devices are observed (see point 2.3.1). The facilities will have to regularise their situation and submit applications to install new devices in already authorised sites or for the creation of new sites with the ARS. The licenses to possess and use a radioactive source or a device emitting ionising radiation issued by ASN shall be updated according to the nature of these changes (change of holder, site, device, sharing of devices, etc.). Nuclear medicine is included in ASN’s inspection priorities. The main radiation protection risks are linked to the use of unsealed sources, which generate radioactive waste and effluents and can lead to contaminations. Nuclear medicine is moreover the main contributor to doses at the extremities of professionals in the nuclear sector (see point 1.2.1). During inspections, particular attention is focused on management of the sources, waste and effluents, occupational radiation protection, control of drug dispensing, through quality assurance obligations and the experience feedback process. 2.3.1 Description of the techniques In vivo diagnostic nuclear medicine allows the production of functional imaging which is complementary to the purely morphological imaging obtained by the other imaging techniques. This technique consists in examining a function of the organism by administering a specific 226 ASN Report on the state of nuclear safety and radiation protection in France in 2024 Medical uses of ionising radiation
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