PET (Positron Emission Tomography) and CT (Computed Tomography) are combined into a single scanning machine known as a PET/CT. The PET scan demonstrates the biological function of the body before anatomical changes take place, while the CT scan provides information about the body's anatomy such as size, shape and location.

A CT scan is obtained in the identical position of the PET scan, allowing a more precise matching of areas of abnormal metabolic activity to the corresponding anatomical structures. By combining these two scanning technologies, a PET/CT scan enables physicians to more accurately diagnose and identify cancer and brain disorders.