Fludeoxyglucose (18F)

Fludeoxyglucose (¹⁸F) (INN) or fluorodeoxyglucose (¹⁸F), commonly abbreviated ¹⁸F-FDG or FDG, is a radiopharmaceutical used in the medical imaging modality positron emission tomography (PET). Chemically, it is 2-deoxy-2-(¹⁸F)fluoro-D-glucose, a glucose analog, with the positron-emitting radioactive isotope fluorine-18 substituted for the normal hydroxyl group at the 2' position in the glucose molecule.

After ¹⁸F-FDG is injected into a patient, a PET scanner can form images of the distribution of FDG around the body. The images can be assessed by a nuclear medicine physician or radiologist to provide diagnoses of various medical conditions.

Mechanism of action, metabolic end-products, and metabolic rate

FDG, as a glucose analog, is taken up by high-glucose-using cells such as brain, kidney, and cancer cells, where phosphorylation prevents the glucose from being released again from the cell, once it has been absorbed. The 2' hydroxyl group (—OH) in normal glucose is needed for further glycolysis (metabolism of glucose by splitting it), but FDG is missing this 2' hydroxyl. Thus, in common with its sister molecule 2-deoxy-<small>D</small>-glucose, FDG cannot be further metabolized in cells. The ¹⁸F-FDG-6-phosphate formed when ¹⁸F-FDG enters the cell thus cannot move out of the cell before radioactive...
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