∙ robotic stereotactic radiotherapy; CyberKnife® is a miniaturised linear accelerator mounted on a robotic arm; ∙ multi-purpose linear accelerators equipped with additional collimation means (mini-collimators, localisers) that can produce mini-beams. A new mono-energy radiotherapy accelerator, a self-shielded gyroscopic platform called “ZAP-X®” (ZAP Surgical, 3 MV, FFF mode) was authorised in March 2023 for use in France for stereotactic intracranial radiotherapy and radiosurgery (see Canpri opinion in point 1.3.2 and box opposite). Since 2018, the combination of a linear accelerator for radiotherapy coupled with an MRI scanner has been developing. Contact therapy or contact radiotherapy is an external-beam radiotherapy technique. The treatments are delivered by an X-ray generator using low-energy beams which are particularly suited to the treatment of skin cancers because the delivered dose decreases rapidly with depth. Intraoperative radiotherapy combines surgery and radiotherapy, with the radiation dose being delivered in the operating theatre to the tumour bed after surgical removal of the tumour. It is primarily a technique for treating small cancers of the breast, certain colorectal cancers and certain cancers of the abdominal stage (pancreas, liver). In April 2016, the HAS published the results of the assessment of this practice for breast cancers and concluded that the conditions necessary to propose coverage by the state health insurance scheme were not satisfied at the time. It considers that the clinical and medico-economic studies must be continued in order to have clinical data over the longer term. Nevertheless, some intraoperative electron radiotherapy devices, with the “CE” marking, have been put on the market. They allow optimal irradiation of the tumour while preserving the surrounding healthy tissues to the maximum extent possible. Hadron therapy is a treatment technique based on the use of beams of charged particles (hadrons comprising protons and carbon ions), which can deliver the dose in a highly localised manner during treatments, thereby drastically reducing the volume of healthy tissue irradiated. According to its advocates, hadron therapy with carbon nuclei is more suited to the treatment of the most radiation-resistant tumours and could result in several hundred additional cancer cases being cured each year. Adaptive radiotherapy is a radiotherapy technique that takes into account the movements and deformations of the organs and the tumour during the treatment. The treatment planning system recalculates the dose distribution before the each delivery of the treatment fraction of the day, this new dose distribution is either accepted or not by the radiation oncologist. It is also possible to associate real-time monitoring (gating) of the target volume during delivery of the treatment. If the target volume goes out of the temporal gate, the treatment stops and resumes as soon as the target volume returns to within the tolerated movement limits (often set at ≤ 1 mm). This technique is still relatively recent and only used by a few centres that are already equipped for it, even if the trend is moving upwards. Given this context, ASN wanted to encourage an initiative to assess this new technique. To this end, in late 2023 it initiated a study with the SFRO and the National Council of Radiation Oncologists (CNPO) to collect the data necessary for a large-scale assessment before the technique becomes widely adopted in France. A steering committee in which participate the HAS, the DGS, the General Directorate of the Healthcare Offering (DGOS), the National Cancer Institute (INCa), IRSN, the SFRO and the CNPO, has been set up by ASN to conduct and follow-up this study in compliance with the rules of good assessment practice. 2.1.2 Technical rules applicable to external-beam radiotherapy facilities On account of the high dose rate when delivering the dose to the patient, the devices must be installed in rooms specially designed to guarantee radiation protection of the staff, turning them into veritable bunkers in which the wall thickness can vary from 1 to 2.5 metres 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. The current conditions of design of these rooms was reviewed in 2019. A specific study must be carried out for each installation by the machine supplier, together with the medical physicist and the Radiation Protection Advisor (RPA). 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 or 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. A first application for a license to possess and use this device (*) was filed in France in April 2022 with the Paris division of ASN by the Porte de Saint-Cloud Cancerology Centre (Boulogne-Billancourt, Hauts-deSeine département). After examining the application documents and with the assistance of IRSN for occupational radiation protection, ASN issued the licence on 27 March 2023. Particular requirements have been set in the licence issued by ASN in order to better characterise the worker exposure levels, given the limited data provided by the manufacturer. The first patient was treated in April 2023 and more than 115 treatment sessions have now been carried out. The first results concerning occupational exposure are expected in the 1st quarter 2024. * Manufacturer: ZAP Surgical, USA, “CE” marked obtained in February 2021. ZAP-X® GYROSCOPIC STEREOTACTIC INTRACRANIAL RADIOTHERAPY AND RADIOSURGERY PLATFORM ASN Report on the state of nuclear safety and radiation protection in France in 2023 213 • 07 • Medical uses of ionising radiation 07 05 15 08 11 04 14 06 13 AP 03 10 02 09 12 01
RkJQdWJsaXNoZXIy NjQ0NzU=