positron emission tomography [PET]« Back to Glossary Index
A PET scan creates computerized images of chemical changes that take place in tissue. In this test, various radioactive materials (tracers) and substances are injected into patients’ veins. The patient is then scanned in a special machine or scanner. Radiologists can then identify activity in certain parts of the brain by measuring blood flow and oxygen and glucose metabolism in the tissues of the working brain.