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 assessing their activity. When injected into a patient, FDG accumulates in areas of increased glucose metabolism. This property helps doctors visualize and diagnose various conditions, including cancers, infections, and neurological disorders. The images produced from FDG-PET scans provide valuable information for treatment planning and monitoring.