High Quality Content by WIKIPEDIA articles! Fluorodeoxyglucose (18F) or fludeoxyglucose (18F) (INN), 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.