ASN Report 2018

The installation of semi-conductor cameras (CZT -Cadmium Zinc Telluride), which have very high detection sensitivity, is continuing to develop, particularly in healthcare centres performing a large number of examinations of the myocardial function. These cameras effectively provide for faster and more comfortable scintigraphic imaging and give a more reliable diagnosis. Research in this area is continuing with the installation in 2018 of a CZT 3D and whole body gamma-camera allowing spatial viewing of the entire body. According to the survey conducted with the nuclear medicine units in 2018, the installed pool of SPECT and CZT cameras comprises: ∙ ∙ 423 SPECT cameras, of which 70% are coupled to a computed tomography (CT) scanner, accounting for 924,000 procedures per year; ∙ ∙ 51 semi-conductor cameras (CZT), of which 7 are coupled to a CT scanner, accounting for 125,000 procedures per year. The installed pool of PET cameras comprises: ∙ ∙ 158 PET cameras, all coupled to a CT scanner, accounting for 486,000 procedures per year; ∙ ∙ 4 PET cameras coupled to an MRI system, accounting for 2,016 procedure per year. 4.1.2  – In vitro diagnosis This is a medical biology technique that enables certain compounds contained in biological fluid samples taken from the patient, such as hormones or tumoral markers, to be assayed, without administering radionuclides to the patient. This technique uses assaying methods based on immunological reactions (reactions between antigens and antibodies marked with iodine-125), hence the name Radio Immunology Assay or radioimmunoassay – RIA). The activities contained in the analysis kits designed for a series of assays do not exceed a few thousand becquerels (kBq). Radioimmunology is currently challenged by techniques which make no use of radioactivity, such as immuno-enzymology and chemiluminescence. A few techniques use other radionuclides such as tritium or carbon-14. Here again the activity levels involved are of the order of the kBq. 4.1.3  –  Internal targeted radiotherapy Used for therapeutic purposes, the aim of the administered RPDs is to deliver a high dose of ionising radiation to a target organ for curative or palliative purposes. Two areas of therapeutic application of nuclear medicine can be identified: oncology and non-oncological conditions (treatment of forms of hyperthyroidism, synoviorthesis). Several types of cancer treatment can be identified: ∙ ∙ treatments administered by nonspecific systemic route (thyroid cancer by iodine-131, non-Hodgkin lymphoma by monoclonal antibodies marked with yttrium-90, prostate cancer which has spread to the bones by radium-223, etc.); ∙ ∙ treatments administered by selective systemic route (treatment of liver cancers by administration of microspheres marked with yttrium-90  via a catheter placed in a hepatic artery, treatment of neuroendocrine or prostate cancers by molecules marked with lutetium-177 (lutetium therapy). Some treatments require patients to be hospitalised for several days in specially fitted-out rooms in the nuclear medicine unit to ensure the radiation protection of the personnel, of people visiting the patients and of the environment. The radiological protection of these rooms is adapted to the nature of the radiation emitted by the radionuclides, and the contaminated urine of the patients is collected in tanks. This is particularly the case with the post-surgical treatment of certain thyroid cancers. The treatments are performed by administering iodine-131 with activities varying from 1.1 GBq to 5.5 GBq). According to the 2018 survey of nuclear medicine units, in 2017: ∙ ∙ 6,377 patients received a treatment administering iodine-131 (with hospitalisation); ∙ ∙ 270 patients received a treatment administering lutetium-177; ∙ ∙ 426 patients received a treatment administering yttrium-90, 230 of them with SIR-Spheres® and 196 with TheraSphere®; ∙ ∙ 101 patients received a treatment administering radium-223. For therapeutic purposes, there are 158 Internal Targeted Radiotherapy (ITR) hospital rooms distributed over 44 nuclear medicine units (see Graph 9). Other treatments can be on an out-patient basis. Examples include administering iodine-131 to treat hyperthyroidism, strontium-89 or samarium-153 for painful bone metastases, and radium-223 for prostate cancer with bone metastases. One can also treat inflammatory diseases of the joints using colloids marked with yttrium-90, erbium-169, or rhenium-186. Finally, radioimmunotherapy can be used to treat certain lymphomas using yttrium-90 labelled antibodies. More than 6,500 patients were treated without hospitalisation in 2017, chiefly with iododine-131 and, to a lesser extent, for synoviortheses or palliative treatment of metastatic pains. 4.1.4  –  Research in nuclear medicine involving humans Nuclear medicine research conducted on humans has been particularly dynamic in the last few years, with the regular introduction of protocols involving new radionuclides and vectors. Research focusing on the use of new tracers is continuing as much in diagnostic imaging (fluorine‑18- fluoroestradiol, development of peptides marked with gallium-68, cardiac applications of iodine-124, exploration of lung ventilation by aerosols marked with gallium-68, etc.) as in therapy (development of new molecules marked with lutetium-177, molecules marked with copper-64, etc.). The use of new radiopharmaceuticals means that the radiation protection requirements associated with their use must be integrated as early as possible in the process. Indeed, given the activity levels involved, the characteristics of certain radionuclides and the preparations to produce, appropriate measures must be implemented with regard to operator exposure and environmental impact. ASN report on the state of nuclear safety and radiation protection in France in 2018  217 07 – MEDICAL USES OF IONISING RADIATION 07