positron emission tomography (PET) scan

Definition of positron emission tomography scan
National Cancer Institute

positron emission tomography scan

(PAH-zih-tron ee-MIH-shun toh-MAH-gruh-fee skan)
A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is taken up. Because cancer cells often take up more glucose than normal cells, the pictures can be used to find cancer cells in the body. Also called PET scan.

Source: NCI Dictionary of Cancer Terms