ASN Report 2018

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 (Graph 9), some 400 radiation-proof enclosures are installed in the departments, divided roughly equally between «low energy» (1 to 2 per department) and «high energy» (1 to 6 per department) enclosures. There are also nearly 110 automated or semi-automated devices for preparing radiopharmaceuticals marked with fluorine-18 and about 60 automated injection devices. 4.1.1  – In vivo diagnosis This technique consists in examining an organ or a function of the organism with a specific radioactive substance – called a radiopharmaceutical – administered to a patient. The nature of the radiopharmaceutical depends on the studied organ or function. The radionuclide can be used directly or fixed to 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 radiopharmaceuticals marked with other positron emitters, notably gallium-68, are starting to be used. PET cameras equipped with the TOF (Time of Flight) system allow a lower activity radiopharmaceutical to be injected while still obtaining satisfactory image quality. Nuclear medicine enables functional images to be produced. It is therefore complementary to the purely morphological images obtained using the other imaging techniques. In order to make it easier to merge functional and morphological images, hybrid appliances have been developed: Positron-Emitting Tomography (PET) scanners are now systematically coupled with a CT scanner (PET-CT) and gamma-cameras are equipped with a CT scanner (SPECT-CT). Distribution of the number of nuclear medicine departments, the number of cameras installed and the number of radiation-protected rooms inspected by ASN in 2018 0 20 40 60 80 100 120 140 Strasbourg Division Paris Division Orléans Division Nantes Division Marseille Division Lyon Division Lille Division Dijon Division Châlons-en- Champagne Division Caen Division Bordeaux Division Departments Cameras ITR rooms Diagram 9 Main radionuclides used in diverse in vivo nuclear medicine explorations TYPE OF EXAMINATION RADIONUCLIDES USED Thyroidmetabolism Iodine-123, Technetium-99m Myocardial perfusion Thallium-201, Technetium-99m, Rubidium-82 Lung perfusion Technetium-99m Lung ventilation Technetium-99m, Krypton-81m Osteo-articular process Technetium-99m, Fluorine-18 Renal exploration Technetium-99m Oncology - search for metastasis Technetium-99m, Fluorine-18, Gallium-68 Neurology Technetium-99m, Fluorine-18 Table 3 216  ASN report on the state of nuclear safety and radiation protection in France in 2018 07 – MEDICAL USES OF IONISING RADIATION