18FFDG

18F-fluorodeoxyglucose (18F-FDG) is a radiopharmaceutical used in positron emission tomography (PET) imaging to assess cellular glucose metabolism. It is the radiolabeled glucose analog 2-deoxy-2-[18F]fluoro-D-glucose, with fluorine-18 providing positron emission for PET. After intravenous administration, FDG is transported into cells via glucose transporters and phosphorylated by hexokinase to FDG-6-phosphate, which is not further metabolized in the glycolytic pathway and becomes trapped inside the cell. This trapping allows regional accumulation of radioactivity to reflect tissue glycolytic activity.

PET imaging with 18F-FDG is typically combined with computed tomography (CT) or magnetic resonance (MR) to provide anatomical localization. The uptake is commonly quantified using standardized uptake values (SUVs), enabling comparison across regions or over time. Imaging protocols usually require patient fasting for several hours and monitoring of blood glucose, as hyperglycemia can reduce FDG uptake in target tissues.

Clinical use is widespread and diverse. In oncology, 18F-FDG-PET is used for tumor detection, staging, restaging, and monitoring response to therapy, as many cancers exhibit elevated glycolysis. In neurology, it helps assess cerebral glucose metabolism patterns, aiding in differential diagnosis and research on neurodegenerative diseases; in epilepsy, it can help localize seizure foci. In cardiology, FDG-PET can assess myocardial viability in patients with ischemic heart disease.

Limitations include uptake in normal high-metabolic-rate tissues (brain, heart), and in inflammatory or infectious processes, which can cause false positives. Not all tumors are FDG-avid, and small lesions may be below PET resolution. Safety is governed by standard radiopharmaceutical practices, with radiation exposure corresponding to the injected activity.