Fluorine-18 (18F) is a fluorine radioisotope which is an important source of positrons. It has a mass of 18.0009380 u and its half-life is 109.771 minutes. It decays by positron emission 97% of the time and electron capture 3% of the time. Both modes of decay yield stable oxygen-18.
Fludeoxyglucose (18F) (INN), or fludeoxyglucose F 18 (USAN and USP), also commonly called fluorodeoxyglucose and abbreviated [18F]FDG, 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.
The uptake of 18F-FDG by tissues is a marker for the tissue uptake of glucose, which in turn is closely correlated with certain types of tissue metabolism. After 18F-FDG is injected into a patient, a PET scanner can form two-dimensional or three-dimensional images of the distribution of 18F-FDG within the body.
Since its development in 1976, 18F-FDG had a profound influence on research in the neurosciences.
The subsequent discovery 1980 that 18F-FDG accumulates in tumors underpins the evolution of PET as a major clinical tool in cancer diagnosis. 18F-FDG is now the standard radiotracer used for PET neuroimaging and cancer patient management.
F-fluorodeoxyglucose, being a radiolabeled glucose analogue, is a marker of glucose metabolism indicator. Since glucose uptake is increased in malignant tumors, its major application is in oncology. However, an increased 18F-fluorodeoxyglucose uptake is found in various benign tumors, granulomatous diseases, tuberculosis, inflammation, infection. A healing process may be interpreted as a false positive finding. In contrast, some types of renal cell cancers and lymphomas, neuroendocrine tumors, colonic mucinous adenocarcinomata, hepatocellular carcinomas, prostate cancer, and carcinoid tumors have low “F-fluorodeoxyglucose avidity which may give a misleading false negative result. In addition, an increased “F-fluorodeoxyglucose uptake in the bone marrow may be seen in oncologycal patients following various types of therapy.
The images can be assessed by a nuclear medicine physician or radiologist to provide diagnoses of various medical conditions.