Glossary Term:


positron emission tomography


<b>pahs</b>-uh-trahn ee-<b>mish</b>-uhn tom-<b>ahg</b>-ruh-fee


also called a PET scan. An imaging method that creates a picture of the body (or of biochemical events) after the injection of a very low dose of a radioactive form of a substance such as glucose (sugar). The scan computes the rate at which the tumor is using the sugar. All cells use sugar, but high-grade tumors use more sugar than normal and low-grade tumors use less than high-grade ones. PET scans may be used to find tumors or see how well a tumor is responding to treatment. See also grade, imaging studies, nuclear medicine, radioisotope.