2.2.3 Radiation protection situation in brachytherapy ASN has licensed 60 brachytherapy centres, 52 of which use the HDR technique. In 2022, 18 licenses were updated (see Graph 3). The brachytherapy activity is stable. The INCa observatory has recorded 500 to 600 LDR treatments per year using iodine-125 seeds, 650 to 800 PDR treatments per year for gynaecological cancers, and about 3,000 HDR treatments per year. In the same way as for external-beam radiotherapy, the safety of brachytherapy treatments has been a priority area of ASN oversight since 2007, because of the intensity of the doses delivered and, where applicable, the high dose rates. As brachytherapy is carried out within the radiotherapy departments, the inspection programme for the 2020‑2023 period is identical to that for external-beam radiotherapy, with a four-yearly frequency and checks similar to those applied in external-beam radiotherapy (see point 2.1.3.2). On account of the use of high activity sources, specific checks focus on medical staff 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 2022, 14 inspections were carried, representing a quarter of the licensed departments; three of these inspections were conducted in combined mode (remotely and on-site). 2.2.3.1 Management of sources The management of brachytherapy sources is considered satisfactory. Thus, all the centres inspected in 2022 record the tracking of source movements, transmit the source inventory to IRSN and store the sources waiting to be loaded or collected in a suitable place. The organisational measures in place enable the category of each source or batch of sources to be identified in all the inspected centres and in three-quarters of the centres the personnel have been issued with the necessary authorisations to access the high-activity sealed sources. Furthermore, 75% of the inspected centres have put in place appropriate measures to prevent unauthorised access to these sources. ASN observes that deployment of the new requirements concerning safeguarding access to high-activity sources continues to progress, but some departments are having difficulties due to the cost of the necessary compliance work. 2.2.3.2 Emergency situations and management of malfunctions Malfunctions of brachytherapy devices which can result in jams or incorrect positioning of the source can lead to overexposure – sometimes serious – of staff or patients. Consequently, this type of event underlines the need to comply with the technical requirements concerning the use of these devices, and the obligations to provide training in emergency situation management and to conduct exercises. 2.2.3.3 Radiation protection of medical professionals The occupational radiation protection measures deployed in 2022 by the brachytherapy departments were considered satisfactory. Out of the 16 inspected centres possessing highactivity sources, 88% have put in place enhanced training in emergency situations and have organised situational exercises, particularly for managing situations linked to source jamming. ASN considers that these efforts must be continued in order to reinforce the radiation protection training of medical professionals where high-activity sources are held. 2.2.3.4 Radiation protection of patients As with external-beam radiotherapy, the radiation protection of brachytherapy patients is assessed from the inspections concerning the implementation of the treatment quality and safety management system. The presence of medical physicists in sufficient numbers for the activity was observed in all the centres inspected. A medical physics organisation plan is also available in all the centres inspected. 2.2.3.5 The treatment quality and safety management system The qualitative result of the inspections carried out in 2022 has shown that the majority of brachytherapy departments inspected have deployed the quality management system, with the support of the external-beam radiotherapy departments. A review of the inspections carried out over the 2018‑2022 period and covering all the departments reveals the following trends: ∙ the reporting culture and the organisation for managing reported events are deemed satisfactory for all the departments over the last two years, and the level was already good in 2018 with 85% satisfaction; ∙ the analysis, the defining of corrective actions and building on the lessons learned are considered satisfactory in about two-thirds of the departments (between 60 and 66%), a level that varies little from one year to the next; ∙ the assessment of corrective action effectiveness has been progressing since 2018 but there is still room for improvement. Only a quarter of the departments assessed the effectiveness of corrective actions in 2018, whereas half the inspected centres did so in 2022. Maintenance and quality controls – The majority of the centres have an inventory of the medical devices and a register for recording maintenance operations and quality controls. In the absence of regulatory baseline requirements for the quality controls of brachytherapy devices, the quality controls implemented are based on the recommendations of the manufacturers or learned societies. Guide of the European Society Radiation Oncology (ESTRO) Booklet No. 81 and Guide No. 36 of the French Society of Medical Physics (SFPM). 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 reported in brachytherapy Four ESRs were reported in brachytherapy in 2022 under criterion 2.1 (exposure of patients for therapeutic purposes), one rated level 2 on the ASN‑SFRO scale concerning a dose delivery error due to the use of an inappropriate afterloader in an HDR brachytherapy treatment. One event is linked to the chance discovery of a lost passive dosimeter in a treatment room with a PDR brachytherapy afterloader; the person assigned this dosimeter had retired when it was discovered. 220 ASN Report on the state of nuclear safety and radiation protection in France in 2022 • 07 • Medical uses of ionising radiation 07
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