ASN Report 2020

1. Nuclear-based medical activities 1. Internal Targeted Radiotherapy (ITR) aims to administer a RadioPharmaceutical Drug (RPD) emitting ionising radiation which will deliver a high dose to a target organ for curative or palliative purposes. 2. An RPD is a drug containing one or more radionuclides. RPDs can be used for diagnostic (scintigraphy) or therapeutic (internal targeted radiotherapy) purposes. 1.1  The different activity categories Nuclear-based therapeutic medical activities, particularly those dedicated to the treatment of cancer, include external-beam radiotherapy, brachytherapy and internal targeted radiotherapy (ITR) (1) . Nuclear-based diagnostic medical activities include computed tomography, conventional radiology, dental radiology and diagnostic nuclear medicine. Interventional practices using ionising radiation (Fluoroscopy- Guided Interventional practices) group different techniques used primarily for invasive medical or surgical procedures for diagnostic, preventive or therapeutic purposes. These different activities and the techniques used are presented in sections 2 to 7. 1.2  Exposure situations in the medical sector 1.2.1 Exposure of health professionals The risks for health professionals arising from the use of ionising radiation are firstly the risks of external exposure generated by the medical devices (devices containing radioactive sources, X-ray generators or particle accelerators) or by sealed and unsealed sources (particularly after administering RadioPharmaceutical Drugs – RPDs (2) ). When using unsealed sources, the risk of contamination must also be taken into consideration in the risk assessment (in nuclear medicine and in the biology laboratory). According to the data collected in 2019 by the Institute for Radiation Protection and Nuclear Safety (IRSN), 229,172 people working in the areas of medical and veterinary activities were subject to dosimetric monitoring of their exposure. The average annual individual dose is 0.3 millisievert (mSv). This dose is stable with respect to 2017 and 2018. Radiology activities (radiodiagnosis and interventional radiology) represent the largest proportion (45%) of exposed medical per- sonnel, with a relatively low average annual dose of 0.2 mSv. Nuclear medicine represents 3% of the headcount but the average annual whole-body dose in nuclear medicine personnel is 0.8 mSv. 16,922 medical personnel members (7.4%) were monitored by extremity dosimeters. The average dose at the extremities is 13.94 mSv; it has doubled compared with 2018 (6.22 mSv). 1.2.2 Exposure of patients The patient’s exposure situation differs depending on whether diagnostic or therapeutic medical applications are being considered. In the first case, it is necessary to optimise the exposure to ionising radiation in order to deliver the minimum dose required to obtain the appropriate diagnostic information or to perform the planned interventional procedure; in the second case it is necessary to deliver the highest possible dose needed to destroy the tumoral cell while at the same time preserving the healthy neighbouring tissues to the greatest possible extent. Whatever the case however, control of the doses delivered during imaging examinations and treatments is a vital requirement that depends not only on the skills of the patient radiation protection professionals but also on the procedures for optimising and maintaining equipment performance. Controlling doses in medical imaging remains a priority for ASN which, following on from the first plan initiated in 2011, published a new opinion on 24 July 2018, along with a second plan, in order to continue promoting a culture of radiation protection with the professionals (see chapter 1). 1.2.3 Exposure of the public With the exception of incident situations, the potential impact of medical applications of ionising radiation is likely to concern: ∙ members of the public who are close to facilities that emit ionising radiation; ∙ persons close to patients having received a nuclear medicine treatment or examination, involving in particular radionuclides such as iodine-131, or brachytherapy using iodine-125; ∙ sewage network and wastewater treatment plant personnel who could be exposed to effluents or wastes produced by nuclear medicine departments. The available data on the impact of these discharges on the public (persons outside the health care institution) lead to estimated doses of a few tens of microsieverts per year for the most exposed persons, notably persons working in sewage networks and wastewater treatment plants (IRSN studies, 2005 and 2014). 1.2.4 The environmental impact The available information concerning radiological monitoring of the environment carried out by the IRSN, in particular the measurement of ambient gamma radiation, on the whole reveals no significant exposure level above the variations in the background For more than a century now, medicine has made use of ionising radiation produced either by electric generators or by radionuclides in sealed or unsealed sources for both diagnostic and therapeutic purposes. The benefits and usefulness of these techniques have long been proven, but they nevertheless contribute significantly to the exposure of the population to ionising radiation. They effectively represent the second source of exposure for the population (behind exposure to natural ionising radiation) and the leading source of artificial exposure (see chapter 1). Medical uses of ionising radiation 07 208 ASN Report on the state of nuclear safety and radiation protection in France in 2020