Fluorodeoxyglucose (FDG) is a radiopharmaceutical used in medical imaging, particularly in positron emission tomography (PET) scans. It is a glucose analog that contains a radioactive fluorine isotope, allowing it to be tracked in the body. FDG is taken up by cells, especially those with high metabolic activity, such as cancer cells, making it useful for detecting tumors and monitoring their response to treatment. In a typical procedure, a small amount of FDG is injected into the patient, who then waits for a short period to allow the substance to distribute throughout the body. The PET scan captures images that reveal areas of increased glucose metabolism, helping doctors diagnose conditions like cancer, infections, and certain neurological disorders.