The estimated doses for the public (people external to the health facility) resulting from discharges from nuclear medicine departments are a few tens of microsieverts (µSv) per year for the most exposed people, primarily the personnel working in sewage networks and wastewater treatment plants (IRSN studies, 2005 and 2014). In 2015, IRSN developed an aid baptised CIDRRE (French acronym for “Calculation of the impact of radioactive discharges into wastewater networks”). This aid enables nuclear medicine departments to estimate, with reasonably penalising assumptions, conservative dose values for the sewage system workers based on the activities they administer to patients or use in their research work. Situations of exposure of waste treatment personnel associated with the handing of radio- active waste from nuclear medicine departments or healthcare services or produced by patients at home are exceptional and of very limited scale, even if radiation portal monitors do get activated from time to time at the entrance to waste treatment facilities, in which case complex operations are required (sorting, characterisation, etc. – see point 2.3.3.4). The number of exposures of pregnant women unaware of their pregnancy notified to ASN decreased by 7% in 2024 compared with 2023. This represents 17% of the Significant Radiation Protection Event (ESR) notifications in 2024 (see point 2.7) compared with 26% on average over the previous 10 years. This figure, which fluctuates regularly, has been following a downward trend since 2021. At the end of 2021, ASN published a “Patient Safety” bulletin entitled Ionising radiation: limiting exposures of women unaware of their pregnancy which is gradually bearing fruit. These events occur primarily in computed tomography (60% of events in 2024), illustrating the benefit of developing the systematic adoption of pregnancy screening tests in these imaging centres. It should also be pointed out that the number of notifications of accidental in utero exposures of embryos or foetuses in nuclear medicine almost doubled in 2024 compared with 2023. This is the first time the number of notifications in this speciality exceeds that for conventional radiology. The doses delivered to the uterus in these imaging examinations are less than 100 milligrays (mGy). This value is below the value for which no increase in malformations or reduction in intellectual quotient has been detected to date in comparison with spontaneous risks (estimated at 3%)(3). The exposure of pregnant women unaware of their pregnancy during therapeutic treatments using ionising radiation could, given the higher doses than in diagnostic imaging, 3. ICRP Publication 84. Ann. ICRP 30. ICRP Supporting Guidance 2. Ann. ICRP 31. ICRP Publication 90. Ann. ICRP 33. ICRP Publication 103. Ann. ICRP 37, ICRP Publication 105. Ann. ICRP 37. 4. IRSN Report No.2021‑00848 on the estimation of the impact on the public of effluents containing radionuclides coming from nuclear medicine departments and research laboratories. exceed 100 mGy depending on the zone treated. The exposure of a foetus to more than 100 mSv may lead the patient to decide to have an abortion. In nuclear medicine the administration of a RadioPharmaceutical Drug (RPD) also exposes the medical professionals who are involved in dispensing and/or monitoring the treatment (who are subject to monitoring as mentioned earlier in point 1.2.1) and can potentially expose the patient’s family and comforters. The regulations have introduced the notion of “dose constraints” for the patient’s family circle in order to control such exposure. To verify compliance with these dose constraints with respect to the patient’s family circle, equivalent ambient dose rate measurements can be taken before discharging a patient who has undergone a nuclear medicine procedure. In clinical practice, nuclear medicine departments make the discharging of patients having received a high activity (therapeutic application) conditional on an equivalent dose rate of about 20 microsieverts per hour (µSv/h) at a distance of 1 m (recommendations of the GPRP in Medical Applications – October 2017. It is usually necessary to hospitalise the patient in a radiation-proof room while waiting for the activity to decay. The introduction of new RPDs will lead to the updating of the instructions for the carers and family circle. The working group tasked with patient radiation protection (GT RPP) is working to establish recommendations for harmonising practices in nuclear medicine departments and the information to give to patients’ carers and family circle (see chapter 2). 1.2.4 The environmental impact In nuclear medicine, the radioactive sources administered to the patients will undergo physical decay (period of time stemming from their physical-chemical properties) but also biological elimination (resulting from the biological metabolism, as with any medication). Patients having received an injection eliminate part of the administered radioactivity, mainly via the urinary tract. Nuclear medicine departments are designed and organised for the collection, storage and disposal of the radioactive waste and effluents produced in the facility, particularly the radio- nuclides contained in patients’ urine (see point 2.3.2), and are required to draw up an Effluents and Waste Management Plan (EWMP) detailing the collection, management and disposal arrangements. In addition, a discharge monitoring system must be put in place. The environmental impact of using ionising radiation for medical purposes is measured by the environmental radiological monitoring ensured by IRSN (see chapter 3). The measurement results are approximately equivalent to the background radiation. Radioactivity measurements in major rivers or wastewater treatment plants of large towns occasionally reveal the presence of artificial radionuclides used in nuclear medicine (iodine-131, for example; assessment of the radiological condition of the French environment from 2018 to 2020). However, no trace of these radionuclides has been detected in water intended for human consumption (see chapter 1). Furthermore, the bibliographic study conducted by IRSN(4) in 2021 reveals a low radiological impact on the public of the radioactive discharges from nuclear medicine departments into the sewage systems (from its analysis of two French studies, IRSN estimates that the exposure of people living near wastewater treatment plants is less than 1 microsievert per year – μSv/year). 1.3 Regulations 1.3.1 General regulations Protection of the personnel working in facilities that use ionising radiation for medical purposes is governed by the provisions of the Labour Code (Articles R. 4451‑1 to R. 4451‑146). In order to protect the public and the workers, the facilities that use MDs emitting ionising radiation must also satisfy the technical rules defined in the ASN resolutions (see technical rules described in points 2.1.2, 2.2.2, 2.3.2, 2.4.2, 2.5.2 and 2.6.2 of this chapter). The monitoring of sources (radioactive sources including RPDs, devices emitting ionising radiation, particle accelerators) is subject to specific rules figuring in the Public Health Code (Articles R. 1333‑152 to R. 1333‑164). These rules concern the acquisition, distribution, import, export, sale, transfer, recovery and disposal of the sources. If the sources are not exempted, they must be notified, registered or licensed, depending on their nature. The sources are inventoried and then taken back when expired, and they can be subject to financial guarantees to ensure their recovery by the supplier. 1.3.2 Radiopharmaceutical drugs and medical devices The radionuclides used in nuclear medicine can be classified in two categories: ∙the RPDs, which like all medicinal drugs are subject to obtaining a Marketing Authorisation (MA), issued by either the French Health Products Safety Agency ASN Report on the state of nuclear safety and radiation protection in France in 2024 213 Medical uses of ionising radiation 07 01 02 03 04 05 06 08 09 10 11 12 13 14 15 AP
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