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Introduction and Definition
covers the area of a medical practice based on injected radioactive substances, called radiopharmaceuticals, which can be applied for diagnosis (radiodiagnostics) or therapy (radiotherapeutics), or both ( ).
The radiolabeled product, a substance containing a radioactiveor , travels through the body up to reaching its target. Thanks to a , on which this is grafted, it reaches and accumulates in a specific biological tissue or an organ. This molecule is then useful to locate the targeted tissue or organ (diagnosis), to initiate the destruction of these cells (therapy), or both depending upon the type of attached .
The term radiotracer refers to the notion of minute (trace) amounts of the substances in use, and also to the advantageous ability to “trace” the dissemination of the molecule in the body as a consequence of the linked(light).
The development oftechnology associated with powerful information technology software has resulted in the development of the technology, generating cross sectional images and tri-dimensional pictures. Some radioactive elements can be used for therapeutic purposes thanks to their different physico-chemical properties; indeed, their short distance effect leads to cell destruction. The use of these vectors in association with therapy radionuclides, essentially β or α emitters, is called vectorized or . Such radiolabeled drugs used in therapy are also called radiotherapeutics.
Naturalfirst appeared concomitantly to the creation of the Earth, and the radionuclides that can still be found in soil today are in fact long period or nuclides dating from original matter. As a consequence, man has always been exposed to environmental , whether from terrestrial or cosmic origin, and of course we continue to find these radionuclides in our food and indirectly in each of our body cells.
Ais a substance that degrades in a very constant manner over time and emits one or several radiations. This degradation or is defined by a constant, the period (or ) corresponding to the time it takes for half of the remaining substance to disappear. This is specific for each .
The type of emittedis also specific for each . There are five types of which are of interest to : for diagnosis purposes, rays (γ) and beta plus (or ) emissions (β+) have led to the development of respectively the modalities (Single Emission Computed ) and ( Emission ). Beta minus (β–), (α) radiations and soon conversion or electrons are used in .
Among all the radionuclides with potential in, we shall remember those that are currently most widely used: Iodine-123 and Technetium-99m as γ emitters, Fluorine-18 and Gallium-68 as β+ emitters, Iodine-131 and Lutetium-177 as β– emitters. Newcomers will include Astatine-211 and Actinium-225 in the -emitting series and Tin-117m as emitter.
Radiotherapeutics in Early Stage
NOT CURRENTLY AVAILABLE
The following list is intended to provide information about molecules that came on the market with strong support from theindustry but had to be withdrawn for diverse reasons. There may be some of these drugs that could enter a second life in some remote countries as most of them have mainly been withdraw for marketing and competition reasons and their efficacy is not questionable.
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In order to explain this technology in an accessible way, a reference booklet containing information on
Richard Zimmermann, “La Médecine Nucléaire: la radioactivité pour le diagnostic et la thérapie”, EDP Sciences, France, 2006, 176 pages French language; English translation republished in 2008 (188 pages). And a second edition (217 pages) so far written only in English became available in 2017.