ASN Report 2020

4. Nuclear medicine 4.  asn.fr/Informer/Actualites/Quinze-recommandations-sur-le-deversement-d-eaux-usees-faiblement-contaminees 4.1 P resentation of nuclear medicine activities Nuclear medicine includes all uses of unsealed radioactive sources for diagnostic or therapeutic purposes. Diagnostic uses can be divided into in vivo techniques, based on administration of radionuclides to a patient, and exclusively in vitro applications (medical biology). Functional exploration examinations can combine in vitro and in vivo techniques. A survey conducted in early 2018 with all the nuclear medicine units licensed by ASN was used to establish an inventory of the installed equipment base and its condition, the number of procedures performed using the different technologies, and the human resources. The 2017 data shown below come from that survey. The total annual number of nuclear medicine procedures in France is about 1,537,000 comprising some 900,000 Single Photon Emission Scintigraphy (SPECT) procedures, 125,000 procedures with semiconductor camera detection and some 500,000 Positron Emission Tomography (PET) procedures (see point 4.1.1). Nuclear medicine departments At the end of 2020, this sector of activity comprises 237 nuclear medicine units. The number of ITR rooms nationwide has increased slightly since 2019, going from 155 to 165. These units group the patient management facilities ( in vivo diagnosis) and in a small number of them, a medical biology activity using unsealed sources ( in vitro diagnosis). The ASN regional divisions issued 124 nuclear medicine licenses in 2020. They concerned more specifically changes of cameras or license extensions to permit the use of new radionuclides. Some fifty in vitro diagnostic laboratories were inventoried by ASN in 2019, but this number is tending to drop due to the gradual phasing out of this activity in favour of analysis methods that do not use radionuclides. Medical dispensaries When a medical dispensary is authorised in a health care centre, the room in the nuclear medicine department in which the radio- pharmaceutical drugs are prepared, called the “nuclear pharmacy” or “radiopharmacy”, is part of the medical dispensary. In 2019, there were 128 nuclear pharmacies in the nuclear medicine units in public health care institutions and non-profit private health care institutions, such as the cancer centres. The radiopharmacist is primarily responsible for managing the radiopharmaceutical drug circuit (procurement, possession, preparation, control, dispensing and traceability) and the quality of preparation. The radiopharmacist may be assisted by hospital pharmacy dispensers or radiographers. The equipment Apart from the cameras used in the nuclear medicine units, some 400 radiation-proof enclosures are installed in the departments, divided roughly equally between “low energy” enclosures (one to two per department) and “high energy” enclosures (one to six per department). There are also nearly 110 automated or semi-automated devices for preparing radiopharmaceuticals marked with fluorine-18 and about 60 automated injection devices. Management of effluents from nuclear medicine departments The management of waste and effluents potentially contaminated by radionuclides must be described in a management plan which includes, more specifically, the conditions of monitoring of discharged effluents in accordance with Article R. 1333‑16 of the Public Health Code and ASN resolution 2008-DC-0095 of 29 January 2008. Revision of this resolution began at the end of 2020 and will also lead to an update of ASN Technical Guide No. 18 of 26 January 2012. One of the 15 recommendations of the working group report (4) “Discharging of effluents containing radionuclides from nuclear medicine units and research laboratories into the sewage network” published in June 2019 on asn.fr introduces the notion of setting “contractual” or “management” guidance levels, if applicable, in the discharge license mentioned in Article L. 1331-10 of the Public Health Code. These guidance levels, whose value would be specific to each centre, are management levels which, in the event of a drift in the measurement results, must trigger an investigation and, if necessary, corrections in the centre’s effluents collection and disposal system. ASN called upon the IRSN to propose a measurement protocol and provide each centre with a method for defining their own specific “local” guidance levels. These “local” guidance levels could ultimately figure in the licenses for discharge between the centre generating the wastes and the sewage network managers. 4.1.1 In vivo diagnosis This technique consists in examining an organ or a function of the organism using a specific radioactive substance called a RadioPharmaceutical Drug (RPD) which is administered to a patient. The nature of the RPD depends on the studied organ or function. The radionuclide can be used directly or it can be fixed on a carrier (molecule, hormone, antibody, etc.). Table 3, for example, presents some of the main radionuclides used in various investigations. The administered radioactive substance – often technetium- 99m – is localised in the organism using a specific detector and scintigraphy techniques. This detector, called a scintillation camera or gamma camera, consists of a crystal of sodium iodide (in the majority of cameras) coupled to a computerised acquisition and analysis system. This equipment produces images of the functioning of the explored tissues or organs. The physiological or physiopathological processes can be quantified. The majority of gamma cameras allow tomographic acquisitions, cross-sectional imaging and a three-dimensional reconstruction of the organs (Single-Photon Emission Tomography – SPECT). Fluorine-18, a positron-emitting radionuclide, is commonly used today, frequently in the form of a marked sugar, fluorodeoxyglucose (FDG), particularly in oncology. Its utilisation necessitates the use of a special camera (Positron Emission Tomography – PET camera). The principle of operation of PET cameras is the detection of the coincidence of the two photons emitted when the positron is annihilated in the matter near its point of emission. Other RPDs marked with other positron emitters, notably gallium-68, are starting to be used. PET cameras equipped with the Time of Flight (TOF) system allow a lower activity RPD to be injected while still obtaining satisfactory image quality. ASN Report on the state of nuclear safety and radiation protection in France in 2020 223 07 – MEDICAL USES OF IONISING RADIATION 07