PET-CT (Positron emission tomography)

Positron emission tomography scan, a highly specialized imaging technique that uses short-lived radioactive substances. This technique produces three-dimensional colored images. PET scanning provides information about the body's chemistry that is not available through other procedures. Unlike computerized tomography (CT) and magnetic resonance imaging (MRI), which look at anatomy or body form, PET studies metabolic activity or body function. PET scanning has been used primarily to evaluate problems of the heart and nervous system and to demonstrate the spread of cancer. In particular, PET scanning has been used to assess the benefit of coronary artery bypass surgery, identify causes of childhood seizures and adult dementia, and detect and grade tumors. PET scanning is very sensitive in detecting active tumor tissue, but it does not measure the size of a tumor. The radioisotope used in a PET scan is short-lived, and the amount of radiation exposure the patient receives is about the same as that from two chest X-rays. Because the radiopharmaceutical contains a chemical that is commonly used by the body, PET scanning enables the physician to see the location of the metabolic process. For example, glucose combined with a radioisotope shows where glucose is being used in the brain, the heart muscle, or a growing tumor, etc