Abstracts ASN Report 2019

ŇłŀłĺŅĴŃĻŌє ŃĻłŇłŁ ĵĸĴŀё ĸŀļŇŇĸķ ĴŇ Ĵ ʼnłĿŇĴĺĸ łĹ Ӊׇ ĴŁķ Ĵ ķłņĸіŅĴŇĸ łĹ Ӌׇ ŌѼŀļŁё ņĻĴŃĸķ ĵŌ Ĵ ŀňĿŇļĿĸĴĹ ĶłĿĿļŀĴŇłŅ enabling the intensity of the radiation to be modulated, allows the irradiation of large volumes of complex shape as well as extremely localised lesions, which may be in anatomically independent regions. The system requires the acquisition of images under the treatment conditions of each session for comparison with reference computed tomography images in order to reposition the patient. Ł ӅӃӄӋё ŇĻĸŅĸ ŊĸŅĸ ӅӊׇķĸʼnļĶĸņ łĹ ŇĻļņ ŇŌŃĸ ļŁņŇĴĿĿĸķ ļŁ ŅĴŁĶĸ ҎņłňŅĶĸѓ ĴķļłŇĻĸŅĴŃŌ łĵņĸŅʼnĴŇłŅŌё Ĵ ӅӃӄӌҏє א ِ׏ِ ב ³ɎƺȸƺȒɎƏƬɎǣƬ ȸƏƳǣȒɎǝƺȸƏȵɵ Stereotactic radiotherapy is a treatment method that aims at delivering high-dose radiation to intra-or extracranial lesions with millimetric accuracy through multiple mini-beams which converge at the centre of the target. In stereotactic radiotherapy treatments, the total dose is delivered either in a single session or in a hypofractionated manner, depending on the disease being treated. The term radiosurgery is used to designate treatments carried out in a single session. This technique firstly requires great precision in defining the target volume to irradiate, and secondly that the treatment be as conformal as possible, that is to say that the irradiation beams follow the shape of the tumour as closely as possible. It was originally developed to treat surgically-inaccessible non- cancerous diseases in neurosurgery (artery or vein malformations, benign tumours) and uses specific positioning techniques to ensure very precise localisation of the lesion. It is used more and more frequently to treat cerebral metastases, but also for extra-cranial tumours. This therapeutic technique chiefly uses three specific types of equipment, such as: Ҋ ĴŀŀĴ ŁļĹĸңё ŊĻļĶĻ ňņĸņ ŀłŅĸ ŇĻĴŁ ӄӌӃׇĶłĵĴĿŇіӉӃׇņłňŅĶĸņё permits very precise irradiation. Gamma Knife® acts like a ʼnĸŅļŇĴĵĿĸ ņĶĴĿŃĸĿ łʼnĸŅ ĴŁ ĸŋŇŅĸŀĸĿŌ ŃŅĸĶļņĸ ĴŁķ ķĸĿļŀļŇĸķ ōłŁĸ ҎӈׇňŁļŇņ ļŁ ņĸŅʼnļĶĸҏђ Ҋ robotic stereotactic radiotherapy; CyberKnife® is a miniaturised ĿļŁĸĴŅ ĴĶĶĸĿĸŅĴŇłŅ ŀłňŁŇĸķ łŁ Ĵ ŅłĵłŇļĶ ĴŅŀ ҎӄӌׇňŁļŇņ ļŁ service); Ҋ multi-purpose linear accelerators equipped with additional collimation means (mini-collimators, localisers) that can produce mini-beams. א ِ׏ِ « ג ƏƳǣȒɎǝƺȸƏȵɵ ɖɀǣȇǕ Ə ǼǣȇƺƏȸ ƏƬƬƺǼƺȸƏɎȒȸ ƬȒɖȵǼƺƳ ɎȒ Ə ȅƏǕȇƺɎǣƬ ȸƺɀȒȇƏȇƬƺ ǣȅƏǕǣȇǕ ɀɵɀɎƺȅ A first linear accelerator coupled to a Magnetic Resonance Imaging (MRI) system was installed in the Paoli-Calmette ŁņŇļŇňŇĸ ļŁ ĴŅņĸļĿĿĸ ĴŇ ŇĻĸ ĸŁķ łĹ ŇĻĸ ĹļŅņŇ ĻĴĿĹ łĹ ӅӃӄӋє 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. łĿĿłŊļŁĺ ĴŁ ĸŋŃĸŅŇ ĴņņĸņņŀĸŁŇ ĵŌ ё ĴňŇĻłŅļņĸķ ĸŁŇŅŌ ļŁŇł ņĸŅʼnļĶĸ łĹ ŇĻļņ ŁĸŊ ŇĸĶĻŁļńňĸ ĴŇ ŇĻĸ ĸŁķ łĹ ӅӃӄӋє Ł ӅӃӄӌё ŇŊł łŇĻĸŅ ĶĸŁŇŅĸņ ŊĸŅĸ ĿļĶĸŁņĸķ Ňł Ńłņņĸņņ ĴŁķ ňņĸ ŇĻļņ ŇŌŃĸ łĹ ŀĴĶĻļŁĸё ŁĴŀĸĿŌ ŇĻĸ ĸłŅĺĸņ ŅĴŁŬłļņ ĸĶĿĸŅĶ ĶĸŁŇŅĸ ļŁ Dijon and the ICM Val d’Aurelle in Montpellier. א ِ׏ِ ! ד ȒȇɎƏƬɎ ȸƏƳǣȒɎǝƺȸƏȵɵ Contact therapy or contact radiotherapy is an external-beam radiotherapy technique. The treatments are delivered by an X-ray ĺĸŁĸŅĴŇłŅ ňņļŁĺ ĿłŊіĸŁĸŅĺŌ ĵĸĴŀņ ʼnĴŅŌļŁĺ ĹŅłŀ ӈӃׇŇł ӅӃӃׇľ (kilovolts). These low-energy beams are suitable for the treatment of skin cancers because the dose they deliver decreases rapidly with depth. GRAPH 5 Breakdown, by ASN regional division, of the number of centres and external-beam radiotherapy accelerators inspected and the number of new licenses or license renewals issued by ASN in 2019 0 10 20 30 40 50 60 70 80 90 100 Strasbourg Division Paris Division Orléans Division Nantes Division Marseille Division Lyon Division Lille Division Dijon Division Châlons-en- Champagne Division Caen Division Bordeaux Division Licensed centres Accelerators Authorisations ASN Report on the state of nuclear safety and radiation protection in France in 2019 205 ׎ ٲ ו MEDICAL USES OF IONISING RADIATION 07