Positron Emission Tomography and Computed Tomography (PET/CT) are both standard imaging tools healthcare providers use to pinpoint disease states in the body. The PET scan demonstrates biological function of the body (i.e. cell physiology). The CT scan provides information on anatomy including size, shape, and location of structures in the body. By combining these two noninvasive technologies healthcare providers can more accurately and quickly diagnose, stage, and monitor treatment for cancer and also aid in the diagnoses of certain brain disorders. FDG is a radioactive material containing glucose. This tracer material circulates through your body and will be metabolized by your cells and organs. Cancer cells and other diseases utilize FDG differently and PET measures those differences.