ASN Report 2018

∙ ∙ robotic stereotactic radiotherapy (see box); CyberKnife® is a miniaturised linear accelerator mounted on a robotic arm (17 units in service); ∙ ∙ multi-purpose linear accelerators equipped with additional collimation means (mini-collimators, localisers) that can produce mini-beams. 2.1.4  –  Radiotherapy using a linear accelerator coupled to a magnetic resonance imaging system A first linear accelerator coupled to a Magnetic Resonance Imaging (MRI) system was installed in the Paoli‑Calmette Institute in Marseille at the end of the first half of 2018. The combining of these two technologies (linear accelerator and MRI) has raised new questions regarding its clinical use, in terms not only of measurement and calculation of the dose delivered to the patient but also of the quality control of the complete machine concerning both the accelerator and the imaging device. Following an expert assessment by IRSN, ASN authorised entry into service of this new technique at the end of 2018. 2.1.5  –  Contact radiotherapy Contact therapy or contact radiotherapy is an external-beam radiotherapy technique. The treatments involve an X-ray generator delivering low-energy beams varying from 50 to 200 kV. These low-energy beams are suitable for the treatment of skin cancers because the dose they deliver decreases rapidly with depth. 2.1.6  –  Intraoperative radiotherapy Intraoperative radiotherapy combines surgery and radiotherapy, which are carried out at the same time in an operating theatre. The dose of radiation is delivered to the tumour bed during surgical intervention. In March 2011, the French National Cancer Institute (INCa) launched a call for proposals to support the installation of intraoperative radiotherapy equipment for the treatment of breast cancer patients. One of the objectives of this call for proposals was to carry out a medico-economic assessment of radiotherapy treatments involving a small number of sessions compared with standard breast cancer treatments. Seven projects deploying an INTRABEAM® accelerator producing X-rays with a voltage of 50 kV were selected and launched between 2011 and 2012. The French National Authority for Health (HAS) published the results of its assessment in April 2016. According to the HAS, current knowledge is insufficient to demonstrate the benefits of intraoperative radiotherapy in the adjuvant treatment of breast cancer compared with standard external-beam radiotherapy. The HAS concludes that at present, the elements necessary to propose that it be covered by the health insurance scheme are not yet established and considers that the clinical and medico- economic studies must be continued in order to acquire clinical data over the longer term. At the end of this assessment, the HAS does however recommend continuing the assessment of intraoperative radiotherapy for clinical research purposes. 2.1.7  –  Hadron therapy Hadron therapy is a treatment technique based on the use of beams of charged particles - protons and carbon nuclei - whose particular physical properties ensure highly localised dose distribution during treatment (Bragg’s peak). Compared with existing techniques, the dose delivered around the tumour to irradiate is lower, therefore the volume of healthy tissue irradiated is drastically reduced. Hadron therapy allows the specific treatment of certain tumours. In June 2016, the INCa Stereotactic radiotherapy with robotic arm This technique consists in using a small particle accelerator producing 6 MV photons, placed on the arm of an industrial robot with six degrees of freedom, marketed under the name CyberKnife®. Furthermore, the treatment table is also positioned on a robot of the same type. By combining the movement possibilities of the two robots, it is possible to use multiple, non‑coplanar beams to irradiate small tumours that are difficult to access using surgery and conventional radiotherapy. This technique enables irradiation to be carried out under stereotactic conditions, and with respiratory tracking. Given the movement capabilities of the robot and its arm, the usual standards do not apply to the radiation protection of the treatment room and a specific study is therefore required.  NORMANDIE  Proton therapy accelerator of the Archade Centre in Caen In 2018, the Caen division of ASN authorised the François- Baclesse Centre to carry out the acceptance of the proton therapy accelerator of the Archade Centre in Caen and then to treat the first patients by proton therapy. The third French proton therapy centre thus started treating its first patient at the end of July 2018. ASN carried out three on-site inspections during the year, one of them in September after the first treatments. These inspections revealed that the project had been conducted in a highly satisfactory manner, taking account of the recommendations of the GPMED (Advisory Committee for Radiation Protection in Medical and Forensic Applications of Ionising Radiation) concerning innovative techniques in external-beam radiotherapy. The work carried out in the very early stages enabled them to use the prospective risk analysis as a true risk management tool. A second accelerator should be deployed in the years to come; it will be able to be used for hadron therapy treatments and research into beams. 208  ASN report on the state of nuclear safety and radiation protection in France in 2018 07 – MEDICAL USES OF IONISING RADIATION