Abstracts ASN Report 2019

׏ِ ב ِ׏ «ƏƳǣȒɀƺȇɀǣɎǣɮǣɎɵ The effects of ionising radiation on personal health vary from one individual to the next. It is known for example, since it was ņŇĴŇĸķ ĹłŅ ŇĻĸ ĹļŅņŇ Ňļŀĸ ĵŌ ĸŅ峣ļų ĴŁķ ŅļĵłŁķĸĴň ļŁ ӄӌӃӉё that a given dose does not have the same effect when received by a growing child or by an adult. ňŅŇĻĸŅŀłŅĸё ŇĻĸ ʼnĴŅļĴĵļĿļŇŌ ļŁ ļŁķļʼnļķňĴĿ ŅĴķļłņĸŁņļŇļʼnļŇŌ Ňł ĻļĺĻ doses of ionising radiation has been extensively documented by radiotherapists and radiobiologists. High levels of radiosensitivity have been observed in persons suffering from genetic diseases affecting the repair of DNA and cellular signalling; in these individuals they can lead to “radiological burns”. At low doses, there is both cell radiosensitivity and individual ŅĴķļłņĸŁņļŇļʼnļŇŌё ŊĻļĶĻ ĶłňĿķ ĶłŁĶĸŅŁ ĴĵłňŇ ӈׇŇł ӄӃՌ łĹ ŇĻĸ population. Thanks to the lowering of detection thresholds, recent methods of immunofluorescence of molecular targets for signalling and repairing DNA damage enable the effects of ionising radiation at low doses to be better documented. The biochemical and molecular effects of a simple X-ray examination then become visible and measurable. The results of the research work conducted using these new investigation methods must still be confirmed in the clinical environment before being integrated into medical practices. Progress in research and the confirmation of clinical results should allow the optimum conditions for monitoring individual radiosensitivity in patients to be rapidly defined. Under the work of the European research group on low doses (MELODI, Multidisciplinary European Low Dose Initiative), ŇŊł ŅĸʼnļĸŊ ķłĶňŀĸŁŇņ ŊĸŅĸ ŃňĵĿļņĻĸķ ļŁ ӅӃӄӌё ĴķķŅĸņņļŁĺ ŇĻĸ clinical and epidemiological aspects of the individual response to ionising radiation, and the available screening tests and their robustness, respectively. ňŅŇĻĸŅŀłŅĸё ŇĻĸ ŊłŅľļŁĺ ĺŅłňŃ Ҏ ӄӄӄҏ ķĸķļĶĴŇĸķ Ňł ŇĻļņ subject is preparing, on the basis of acquired knowledge, radiation protection recommendations that it plans publishing in 2020. The individual response to ionising radiation is thus gradually being recognised as an important subject of research and application in radiobiology and radiation protection, while at the same raising ethical and societal questions. ׏ِ ב ِ א 0ǔǔƺƬɎɀ Ȓǔ ǼȒɯ ƳȒɀƺɀ • Áǝƺ nǣȇƺƏȸ zȒ ٮ ÁǝȸƺɀǝȒǼƳ ٢nzÁ٣ ȸƺǼƏɎǣȒȇɀǝǣȵ The hypothesis of this relationship, adopted to model the effects of low doses on health (see point 1.2), albeit practical from the regulatory standpoint and albeit conservative from the health standpoint, is not as scientifically well-grounded as might be hoped for. Some feel that the effects of low doses could be higher, while others believe that these doses could have no effect below a certain threshold, and some others even assert that low doses have a beneficial effect. Research in molecular and cellular biology is progressing, as are epidemiological surveys of large cohorts. But faced with the complexity of the DNA repair and mutation phenomena, and the methodological limitations of epidemiology, uncertainties remain and the public authorities must exercise caution. 4. The radioactive dose rate determines the absorbed dose (energy absorbed by the material per unit mass and time). It is measured in Gray per second (Gy/s) in the International System of Units (SI). It is used in physics and in radiation protection. • (Ȓɀƺً ƳȒɀƺ ȸƏɎƺ ƏȇƳ ƳɖȸƏɎǣȒȇ Ȓǔ ƺɴȵȒɀɖȸƺ The epidemiological studies performed on individuals exposed to the Hiroshima and Nagasaki bombings have given a clearer picture of the effects of radiation on health, concerning exposure due to external irradiation (external exposure) received in a few fractions of a second at high dose and high dose rate (4) . The studies carried out in the countries most affected by the Chernobyl accident (Belorussia, Ukraine and Russia) were also able to improve our understanding of the effects of radiation on health caused by exposure through internal contamination (internal exposure), more specifically through radioactive iodine. Studies on nuclear industry workers have given a clearer picture of the risk associated with chronic exposures at low doses established over many years, whether as a result of external exposure or internal contamination. • RƺȸƺƳǣɎƏȸɵ ƺǔǔƺƬɎɀ The appearance of possible hereditary effects from ionising radiation in humans remains uncertain. Such effects have not been observed among the survivors of the Hiroshima and Nagasaki bombings. However, hereditary effects have been documented in experimental work on animals: mutations induced by ionising radiation in embryonic germ cells can be transmitted to descendants. The recessive mutation of one gene on one chromosome will produce no clinical or biological indications as long as the same gene carried by the other counterpart chromosome is not affected. Although it cannot be absolutely ruled out, the probability of this type of event nonetheless remains low. • 0ȇɮǣȸȒȇȅƺȇɎƏǼ ȵȸȒɎƺƬɎǣȒȇ The purpose of radiation protection is to prevent or mitigate the harmful effects of ionising radiation on individuals, directly or indirectly, including in situations of environmental contamination. Over and beyond environmental protection aiming at the protection of humans and present or future generations, the protection of non-human species as such forms part of the ĸŁʼnļŅłŁŀĸŁŇĴĿ ŃŅłŇĸĶŇļłŁ ŃŅĸņĶŅļĵĸķ ļŁ ŇĻĸ ŅĸŁĶĻ ĶłŁņŇļŇňŇļłŁĴĿ Charter for the Environment. Protection of nature in the specific interests of animal and plant species has been the subject of ņĸʼnĸŅĴĿ ŃňĵĿļĶĴŇļłŁņ ņļŁĶĸ ӅӃӃӋׇҎ ӄӃӋё ӄӄӇׇĴŁķ ӄӅӇҏє Radiography room in the Léon Bourgeois clinic (Paris) in 1916 ASN Report on the state of nuclear safety and radiation protection in France in 2019 101 ׎׏ ٲ NUCLEAR ACTIVITIES: IONISING RADIATION AND HEALTH AND ENVIRONMENTAL RISKS 01