18F-deoxyglucose

PET images of Uptake of 18F-Deoxyglucose in the Brains of a Normal Adult (left) and a Depressed Adult (right). 

PET has been gaining in popularity as a result of its enhanced sensitivity and resolution with respect to SPECT at the millimetre scale, allowing clinicians to study drug distribution in vivo (10). Indeed, it is estimated that by 2010 there will be approximately two million PET scans per year, of which the majority will image the metabolism of the 18F-labeled fluoro-deoxyglucose (FDG) (11). The increased sensitivity in turn reduces the concentration of the administered radiopharmaceutical required to 10 8-10 10M. The much lower concentrations of administered radioactive probe employed reduce the overall... 

Volkow ND, Gillespie H, Mullani N, Tancredi L, Grant C, Ivanovic M, Hollister L. (1991). Cerebellar metabolic activation by delta-9-tetrahydrocannabinol in human brain a study with positron emission tomography and 18F-2-fluoro-2-deoxyglucose. Psychiatry Res. 40(1) 69-78. 

FallavoUita JA, Canty JM, Jr. Differential 18F-2-deoxyglucose uptake in viable dysfunctional myocardium with normal resting perfusion evidence for chronic stuiming in pigs. Circulation 1999 99 2798-2805... 

Buchsbaum MS, Wu J, DeLisi EE, et al Frontal cortex and basal ganglia metabolic rates assessed by positron emission tomography with [18F]2-deoxyglucose in affective illness. J Affect Disord 10 137-152, 1986 Buhot MC, Patra SK, Naili S Spatial memory deficits following stimulation of hippocampal 5-HTjj receptors in the rat. Eur J Pharmacol 285 221-228, 1995... 

Rees JH, Hain SF, Johnson MR, Hughes RA, Costa DC, Ell PJ, et al. The role of [18F] fluoro-2-deoxyglucose-PET scanning in the diagnosis of paraneoplastic neurological disorders. Brain 2001 124(Pt. 11) 2223-2231. 

F-2-fluoro-2-deoxyglucose (2-FDG) is normally produced in places where a cyclotron is locally available. Its molecular formula is CsHn FOs with molecular weight of 181.3 daltons. 18F-2-FDG can be produced by electrophilic substitution with 18F-fluorine gas or nucleophilic displacement with 18F-fluoride ions. The radiochemical yield is low with the electrophilic substitution, so the nucleophilic displacement reaction has become the method of choice for 18F-FDG synthesis. Deoxyglucose is labeled with 18F by nucleophilic displacement reaction of an acetylated sugar derivative followed by hydrolysis (Hamacher et al, 1986). In nucleophilic substitution, a fluoride ion reacts to fluorinate the sugar derivative. A solution of 1,3,4,6-tetra-O-acetyl-2-0-trifluoromethane-sulfonyl-/ -D-mannopyranose in anhydrous acetonitrile is added to a dry residue of 18F-fluoride containing aminopolyether (Kryptofix 2.2.2) and potassium carbonate (Fig. 8.1). Kryptofix 2.2.2 is used as a catalyst to enhance the reactivity of the fluoride ions. The mixture is heated... 

Figure 8.1. Schematic synthesis of 18F-2-Fluoro-2-deoxyglucose (FDG). (Reprinted with the permission of The Cleveland Clinic Center for Medical Art Photography 2009. All Rights Reserved)...

F-2-FDG is used primarily for the study of metabohsm in the brain and heart and for the detection of epilepsy and various tumors. In metabolism, 18F-2-FDG is phosphorylated by hexokinase to 2-FDG-6-phosphate which is not metabolized further. It should be noted that 3-fluoro-deoxyglucose (3-FDG) is not phosphorylated and hence is not trapped and essentially eliminated rapidly from the cell. This is why 3-FDG is not used for metabolic studies. 

Joanna S. Fowler (NAS) is a senior chemist at the U.S. Department of Energy s Brookhaven National Laboratory. Dr. Fowler has been a major contributor to brain research and the study of diseases such as addiction, which she has investigated using the imaging technique positron emission tomography (PET). In 1976 she and her colleagues synthesized 18F-fluoro-deoxyglucose, a radiotracer used in PET. Dr. Fowler earned a B.S. from the University of South Florida and a Ph.D. from the University of Colorado, Boulder. 

Di Chiro G, DeLaPaz RL, Brooks RA, et al. (1982) Glucose utilization of cerebral gliomas measured by [18F]fluoro-deoxyglucose and positron emission tomography. Neurology 32 1323-9... 

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