A positron emission tomography (PET) scan is a type of imaging test that can help reveal how your tissues and organs are functioning.
During the test, a small amount of radioactive material is injected, swallowed, or inhaled to detect areas of disease. The radioactive material accumulates in areas with higher levels of chemical activity. This activity often corresponds with areas of disease and shows up as brighter spots on the scan.
PET scans are useful in evaluating a variety of conditions, including neurological problems, heart disease, and cancer.