Positron emitter synthesis

Keywords. [ F] Fluorine, [ F] Fluoride, Positron emitter. Synthesis, Radioligand... 

Conventional manual methods of synthesis of radiopharmaceuticals using a high level of radioactivity are likely to subject the persons involved in the synthesis to high radiation exposure. This is particularly true with short-lived positron emitters such as UC, 13N, 150, and 18F, because the quantity of these radionuclides handled in the synthesis is very high. To minimize the level of exposure, automated modules have been devised for the synthesis of PET radiopharmaceuticals. 

Synthesis of D-glucose derivatives labelled with positron emitters... 

The use of positron emitters usually requires fast chemical separation and synthesis techniques. Fast chemical separation techniques for producing pure radioisotopes are described in Chapter IS, but for rapid chemical synthesis techniques, specialized texts should be consulted. 

Whilst the work that we focus on in the first part of this chapter concerns the preparation of tritium- and inevitably deuterium-labeled compounds, examples are given where the benefits can also be applied to the carbon ( C, and C)-labeled area [8]. Also discussed is the use of microwaves in the synthesis of radiopharmaceuticals labeled with positron emitters, such as carbon-11 (ti/2 = 20.4 min) and fluorine-18 (ti/2 = 109.7 min). The short half lives of these radioisotopes, together with the requirements for high radiochemical yield (RCY), radiochemical purity (RCP) and specific activity (SA) can benefit from the advantages that micro-waves provide [8, 9]. 

Gaseous and liquid targets are commonly used for the production of short-lived radionuclides, especially positron emitters. The chemical separation techniques of some important positron emitters are described in the next section. It should be pointed out here that the methods used have to be fast and efficient, in terms of the purity of the product as well as the recovery of the enriched target material. Furthermore, the chemical form of the separated radionuclide has to be well defined to allow a convenient synthesis of the desired radiopharmaceutical. 

Scheme 4.40 Synthesis of [ F]2-fluorodeoxy-glucose [87, 89] as the first emitter for positron emission tomography (PET) [84],...

---