2-Fluoro-2-Deoxy-D-Glucose (18F). The only F-18 radiopharmaceutical presently available is fluorine 18F-FDG, the structure of which is shown on next page. Synthesis of 18F-FDG by nucleophilic displacement of a protected mannose triflate derivative, hydrolysis of the protecting groups, and purification by solid phase extraction is the typical method of production.3 The synthetic cascade and subsequent purification is routinely accomplished in about 50 minutes by an automated synthesizer.4,5
The high glycolytic rate of many neoplasms compared with that of the surrounding tissues facilitates tumor imaging with this glucose analog. Both glucose and 18F-FDG are transported into the cell and phosphorylated; however, 18F-FDG does not get catabolized as an energy source, nor is it effectively degraded by glucose-6-phosphatase. Thus, energetically active tissues accumulate 18F-FdG. Because of the widespread anatomical distribution of metastases, a whole-body imaging technique using a tumor-specific radiophar-maceutical, such as 18F-FDG, is very useful for tumor detection and mapping to evaluate the extent and relative metabolic activity of the disease.
18F-FDG can also be used for diagnostic imaging of myo-cardial viability and in the evaluation of seizure disorders.6
Was this article helpful?