The average individual annual dose received is 0.31 millisievert (mSv) in the medical sector and 0.26 mSv in the dental sector. This figure remained relatively stable between 2015‑2023, with the exception of 2020, when it dropped by 17% due to the Covid-19 pandemic (see chapter 1). Among the health personnel liable to be exposed and therefore subject to dosimetry monitoring, those working in radiology (72% of the medical personnel monitored, in diagnostic radiology and intervention radiology alike) receive an average individual annual dose of 0.20 mSv. The nuclear medicine personnel, who represent 5% of the monitored health personnel, are exposed to an average individual annual whole body dose that is four times greater, estimated at 0.78 mSv. It is also in the medical sector that the majority of situations of occupational exposure to the extremities (hands) occur. Consequently 15,403 medical professionals were subject to dosimetric monitoring of the extremities by ring or wrist dosimeter, which represents 60% of the workers monitored in this way and about 60% of the total dose to the extremities. The radio- logy sector has the largest number of monitored workers, with about 68% of the total headcount of medical personnel monitored by dosimetry at the extremities (49% for interventional radiology and 19% for diagnostic radiology), and accounts for 27% of the total exposure dose to the extremities in the medical field. The nuclear medicine sector represents 20% of the monitored personnel and accounts for 68% of the total dose in this area. One hundred and forty-four workers in the dental sector are subject to dosimetry monitoring at the extremities and represent less than 0.1% of the total dose to the extremities. The contribution of interventional activities to the total dose is probably underestimated, particularly due to insufficient use of extremity dosimeters by staff in the operating theatre. Lastly, nearly 84% of the personnel monitored for exposure to the lens of the eye work in medical activities, representing 4,756 workers accounting for 56% of the total dose to the lens of the eye. The average individual dose for medical activities (dental activities excluded) in 2023 was 1.38 mSv. Nearly two-thirds of the personnel monitored for lens of the eye dosimetry work in the FGIP sector which accounts for 70% of the total dose in the medical sector. Two cases of exceeding limit exposure values were registered by the occupational physician in the medical sector: one in effective dose in the dental sector and one in dose to the extremities in interventional radiology (see chapter 1). 2. The ALARA (As Low As Reasonably Achievable) principle appeared for the first time in Publication 26 of the International Commission on Radiological Protection (ICRP) in 1977. It was the culmination of a reflection on the principle of radiation protection optimisation. Acceptance and implementation of the ALARA principle have evolved significantly in Europe over the last thirty years, with close involvement of the European Commission which resulted in the creation of a European ALARA network in 1991. 1.2.2 Exposure of patients In medical applications for diagnostic purposes, the aim of optimising exposure to ionising radiation is to deliver the minimum dose that produces an image of sufficient quality to obtain the relevant diagnostic information or allows performance of the planned interventional procedure. For therapeutic applications, the dose delivered must be much higher than in diagnostic applications in order to destroy the targeted cells while preserving the surrounding healthy tissue as best possible. As the principle of limitation does not apply to patients, the principles of justification and optimisation (see point 1.3) must be applied all the more rigorously. In medical imaging, the principles of optimisation and justification (avoiding unnecessary examinations, or those whose result can be obtained using non-irradiating techniques that give an equivalent diagnostic level when available) are at the centre of the action plans for controlling doses delivered to patients. These action plans were developed by ASN in 2011 and 2018 in collaboration with the services of the Ministry of Solidarity and Health and the health professionals. The action plan of 2018 will be updated after finalising the situation assessment carried out with all the stakeholders. The optimisation principle, defined by Article L. 1333‑2 of the Public Health Code (see chapter 2), known as the ALARA(2) principle, has led to the introduction, in the area of medical imaging using ionising radiation, of the concept of “Diagnostic Reference Levels” (DRLs). These DRLs, which must not be considered to be “dose limits” or “optimum doses”, are established for standard examinations and typical patients. The DRLs are thus dosimetric indicators used to assess the quality of practices. The comparison of a DRL value with a dose received during an individual examination is not relevant for a given individual, because in certain situations the conditions of the examination can justify a higher value (to take into account the patient’s morphology for example, or other factors that do not call into question the benefit/risk of the procedure). The optimisation principle should lead the persons/entities Responsible for a Nuclear Activity (RNAs) that use imaging by ionising radiation to compile their own Local Dose Reference Levels (LDRLs) to continue optimising their practices if this is compatible with obtaining a diagnostic quality image. ASN encourages such practices and wants the medical professionals to generalise them in the interest of the patients. ASN resolution 2019-DC-0667 of 18 April 2019 sets the DRL values and requires heads of radiology and nuclear medicine departments to carry out (or have others carry out) periodic dosimetric evaluations and to send the results to IRSN. The data collected by IRSN are analysed with a view to updating the DRLs. This resolution will be amended in 2025 to introduce new DRL values for Digital Radiography (DR) mammography and tomosynthesis (3D) mammography, and new DRL values for dental Cone Beam Computed Tomography (CBCT). The last “ExPRI” study, which analyses exposure of the French population to ionising radiation due to medical imaging examinations, was published by IRSN in late 2020. It presents the data for 2017, which are compared with those of 2012 to show how they have evolved. These analyses are carried out using diagnostic imaging procedures drawn from a representative sample of beneficiaries of the French health insurance system, by method of imaging (conventional, interventional and dental radiology, CT scans and nuclear medicine), by explored anatomical region, by age and by sex. The analyses reveal stability of exposure on average (see chapter 1, point 3.3). 1.2.3 Exposure of the public The impact of medical applications of ionising radiation is likely to concern: ∙members of the public who live near facilities that emit ionising radiation and the persons working in these facilities who are not workers classified in application of the Labour Code with regard to the radiological risk; ∙embryos or foetuses exposed in utero when pregnant women are exposed for medical purposes; ∙the personnel of the sewage networks and wastewater treatment plants who could be exposed to effluents produced by nuclear medicine departments, and in the event of non-compliance with waste management procedures, the personnel working in waste treatment facilities who could be exposed to waste produced by nuclear medicine departments or by patients at home having received therapeutic nuclear medicine treatment; ∙carers and comforters of patients having received therapeutic nuclear medicine treatment and healthy volunteers participating in biomedical research involving exposure to ionising radiation. The regulatory obligations applicable to these exposures are those that apply to medical exposures. These exposures are therefore not subject to the dose limits for the public but must comply with dose constraints (see below and point 1.3.4). 212 ASN Report on the state of nuclear safety and radiation protection in France in 2024 Medical uses of ionising radiation
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