Abstracts ASN Report 2019

׫٫ ڲ External-beam radiotherapy Ӈє Ł ӅӃӄӋё ӅӃӄёӆӈӅׇŃĸłŃĿĸ ŊļŇĻ ĶĴŁĶĸŅ ŊĸŅĸ ŇŅĸĴŇĸķ ĵŌ ŅĴķļłŇĻĸŅĴŃŌ ļŁ ӇёӅӇӌёӃӈӈׇņĸņņļłŁņ ҎņłňŅĶĸѓ Ĵ ĵņĸŅʼnĴŇłŅŌҏє א ِ׏ (ƺɀƬȸǣȵɎǣȒȇ Ȓǔ Ɏǝƺ ɎƺƬǝȇǣȷɖƺɀ Alongside surgery and chemotherapy, radiotherapy is one of the key techniques employed to treat cancerous tumours. Some ӅӃӃёӃӃӃׇŃĴŇļĸŁŇņ (4) are treated each year, representing nearly ӇєӅׇŀļĿĿļłŁ ļŅŅĴķļĴŇļłŁ ņĸņņļłŁņє ĴķļłŇĻĸŅĴŃŌ ňņĸņ ļłŁļņļŁĺ radiation to destroy malignant cells (and non-malignant cells in a small number of cases). The ionising radiation necessary for the treatments is produced by an electric generator or emitted by radionuclides in sealed sources. We thus have external-beam radiotherapy, where the source of radiation produced by a particle accelerator or radioactive sources (Gamma knife® for example) is external to the patient, and brachytherapy, where the source is placed as close as possible to the area to treat. ĶĶłŅķļŁĺ Ňł ŇĻĸ ļŁĹłŅŀĴŇļłŁ ĺĴŇĻĸŅĸķ ĹŅłŀ ŇĻĸ ŅĸŁĶĻ ĴŇļłŁĴĿ ĴķļłŇĻĸŅĴŃŌ ĵņĸŅʼnĴŇłŅŌ ҎņłňŅĶĸѓ Ĵё ӅӃӄӋҏё ŇĻĸ ŅĴķļłŇĻĸŅĴŃŌ ĹĴĶļĿļŇļĸņ ĶłŀŃŅļņĸ ӈӆӃׇŃĴŅŇļĶĿĸ ĴĶĶĸĿĸŅĴŇłŅņ ļŁ ӄӊӇׇŅĴķļłŇĻĸŅĴŃŌ ĶĸŁŇŅĸņ ņňĵĽĸĶŇ Ňł ĴŁ ĿļĶĸŁņĸє ļņņňĸķ ӌӈׇĿļĶĸŁņĸņ ļŁ ӅӃӄӌє Ļĸ ŀĴĽłŅļŇŌ łĹ ŇĻĸņĸ ĶĴņĸņ ĶłŁĶĸŅŁĸķ ŇĻĸ ňŃķĴŇļŁĺ łĹ ĴŁ existing license. Ļļņ łĵņĸŅʼnĴŇłŅŌ ĻĴķ ӋӄӋׇŅĴķļłŇĻĸŅĴŃļņŇņ łŁ ŅĸĶłŅķ ļŁ ӅӃӄӋє The irradiation sessions are always preceded by preparation of a treatment plan which precisely defines the dose to be delivered, the target volume(s) to be treated, the volumes at risk to be protected, the irradiation beam setting and the estimated dose distribution (dosimetry) for each patient. Preparation of this plan, which aims to set conditions for achieving a high dose in the target volume while preserving surrounding healthy tissues, requires close cooperation between the radiation oncologist, the medical physicist and, when applicable, the dosimetrists In the vast majority of treatments, irradiation is ensured using linear particle accelerators with an isocentric arm emitting ĵĸĴŀņ łĹ ŃĻłŇłŁņ ŃŅłķňĶĸķ ĴŇ Ĵ ʼnłĿŇĴĺĸ ʼnĴŅŌļŁĺ ĹŅłŀ ӇׇŇł Ӆӈׇ ҎŀĸĺĴʼnłĿŇņҏ łŅ ĸĿĸĶŇŅłŁņ ŊļŇĻ ĴŁ ĸŁĸŅĺŌ ĿĸʼnĸĿ łĹ ĵĸŇŊĸĸŁ ӇׇĴŁķ Ӆӈׇ ĸ ҎŀĸĺĴĸĿĸĶŇŅłŁʼnłĿŇņҏ ĴŁķ ķĸĿļʼnĸŅļŁĺ ķłņĸіŅĴŇĸņ ŇĻĴŇ ĶĴŁ ʼnĴŅŌ ĹŅłŀ ӅׇŇł Ӊׇ ŌѼŀļŁ ҎĺŅĴŌņ ŃĸŅ ŀļŁňŇĸҏє Ň ņĻłňĿķ ĵĸ ŁłŇĸķ ŇĻĴŇ some latest-generation linear accelerators can deliver much higher ķłņĸ ŅĴŇĸņё łĹ ňŃ Ňł Ӆӈׇ ŌѼŀļŁ ҎļŁ ŇĻĸ ĶĴņĸ łĹ ŃĻłŇłŁ ĵĸĴŀņҏє א ِ׏ِ׏ Áǝȸƺƺ ٮ ƳǣȅƺȇɀǣȒȇƏǼ ƬȒȇǔȒȸȅƏǼ ȸƏƳǣȒɎǝƺȸƏȵɵ This technique uses three-dimensional images of the target volumes and neighbouring organs obtained with a CT scanner, sometimes in conjunction with other imaging examinations (MRI, PET, etc.). During a three-dimensional conformal radiotherapy treatment, the shape of each beam is fixed and the dose delivered by each beam is uniform within the treatment field delimited by the multi-leaf collimator. In its guide giving recommendations for the practice of external- beam radiotherapy and brachytherapy (Recorad) published in ĸŃŇĸŀĵĸŅ ӅӃӄӉё ŇĻĸ ŅĸŁĶĻ łĶļĸŇŌ ĹłŅ ĴķļĴŇļłŁ ŁĶłĿłĺŌ Ҏ ҏ ĶłŁņļķĸŅņ ŇĻĴŇ ŇĻļņ ļŅŅĴķļĴŇļłŁ ŇĸĶĻŁļńňĸ ļņ ňņĸķ Ĵņ ŇĻĸ ĵĴņļĶ ŇĸĶĻŁļńňĸ ĵŌ ĴĿĿ ŇĻĸ ŅĸŁĶĻ ĶĸŁŇŅĸņ ĹłŅ ĴĿĿ ŃĴŇļĸŁŇņ ŅĸĶĸļʼnļŁĺ curative treatment. It has nevertheless been observed in the last few years that the proportion of treatments using this technique is giving way to intensity-modulated conformal radiotherapy. א ِ׏ِ א XȇɎƺȇɀǣɎɵ ٮ xȒƳɖǼƏɎƺƳ ٢ƬȒȇǔȒȸȅƏǼ٣ «ƏƳǣȒɎǝƺȸƏȵɵ ٢Xx«Á٣ Intensity-Modulated (conformal) Radiotherapy (IMRT) is a ŇĸĶĻŁļńňĸ ŇĻĴŇ ŊĴņ ķĸʼnĸĿłŃĸķ ļŁ ŅĴŁĶĸ ļŁ ŇĻĸ ĸĴŅĿŌ ӅӃӃӃѡņє ŁĿļľĸ 3D conformal radiotherapy, the collimator leaves move during irradiation, enabling the intensity of the beams –and therefore the delivered dose– to be modulated during irradiation to better adapt to complex volumes and better protect the neighbouring organs at risk. • àȒǼɖȅƺɎȸǣƬ ȅȒƳɖǼƏɎƺƳ ƏȸƬ ɎǝƺȸƏȵɵ łĿĿłŊļŁĺ łŁ ĹŅłŀ ё ʼnłĿňŀĸŇŅļĶ ĴŅĶ ŇĻĸŅĴŃŌ ļņ ŁłŊ ĵĸļŁĺ ňņĸķ ŀłŅĸ ĴŁķ ŀłŅĸ ĹŅĸńňĸŁŇĿŌ ļŁ ŅĴŁĶĸє Ļļņ ŇĸĶĻŁļńňĸ consists in irradiating a target volume by continuous irradiation rotating around the patient. Several parameters can vary during the irradiation, including the shape of the multileaf collimator aperture, the dose-rate, the rotation speed of the arm or the orientation of the multileaf collimator. This technique, designated under different terms (VMAT® –Volumetric Modulated Arc Therapy, RapidArc®) depending on the manufacturer, is achieved using conventional isocentric linear accelerators equipped with this technological option. • RƺǼǣƬƏǼ ȸƏƳǣȒɎǝƺȸƏȵɵ Helical radiotherapy, or tomotherapy, enables radiation treatment to be delivered by combining the continuous rotation of an accelerator with the longitudinal movement of the patient during the treatment. The technique employed is similar to the principle of helical image acquisitions obtained with computed TABLE 2 Regulatory work in progress in the area of patient radiation protection EXISTING TEXT WORK IN PROGRESS Quality assurance in radiotherapy «ƺɀȒǼɖɎǣȒȇ א ׎׎ ٮ!(ٮז ׎׏׎ ژב Ȓǔ ׏ ژ hɖǼɵ א ׎׎ ז Updating planned in 2020 Quality assurance inmedical imaging «ƺɀȒǼɖɎǣȒȇ Ȓǔ ׏ ژד hƏȇɖƏȸɵ א ׎׏ ژח ƏȵȵȸȒɮƺƳ ƫɵ…ȸƳƺȸ Ȓǔ ژז IƺƫȸɖƏȸɵ א ׎׏ ח Diagnostic reference level «ƺɀȒǼɖɎǣȒȇ Ȓǔ ׏ ژז ȵȸǣǼ א ׎׏ ژח ƏȵȵȸȒɮƺƳ Ȓȇ ژבא xƏɵ א ׎׏ ח Continuous training of health professionals in the protection of persons exposed to ionising radiation for medical purposes «ƺɀȒǼɖɎǣȒȇ א ׎׏ ٮ!(ٮו ׎ ژדזד Ȓǔ ׏ ژג xƏȸƬǝ א ׎׏ ژו ƏȅƺȇƳƺƳ ƫɵ ȸƺɀȒǼɖɎǣȒȇ Ȓǔ ׏׏ ژ hɖȇƺ א ׎׏ ژח ƏȵȵȸȒɮƺƳ Ȓȇ ژוא ³ƺȵɎƺȅƫƺȸ א ׎׏ ח Qualifications of physicians involved in the exercise of nuclear-basedmedical activities «ƺɀȒǼɖɎǣȒȇ א ׎׏׏ ٮ!(ٮ ׎ ژזבא Ȓǔ ژבא ɖǕɖɀɎ א ׎׏׏ Updating planned in 2020 204 ASN Report on the state of nuclear safety and radiation protection in France in 2019 ׎ ٲ ו MEDICAL USES OF IONISING RADIATION