What Is A PET Scan?

A positron emission tomography scan (PET scan) is a type of imaging test used for diagnosing numerous diseases in an individual's body. PET scans are used to highlight areas of the body where there are increased rates of certain chemical activities. A PET scan can tell a patient's physician about how their body uses oxygen, how their body processes glucose, and about their blood flow. These specialized scans can give a patient's physician insight to problems occurring at the cellular level, helping identify and evaluate certain complex systemic conditions and diseases. The most common issues PET scans are used to identify include brain disorders, cancer, and heart problems. Around two million PET scans are performed annually in the United States.

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How The Scan Works


A PET scan works with the use of a large machine with a hole in the center or a scanning device to pick up subatomic particles or photons emitted by a radiotracer in the tissues or organ being examined. The radiotracer used for a PET scan depends on the particular tissues or organs that are of interest and the purpose of the scan. The selected radiotracer is administered to the patient's body through a vein in their arm via an intravenous line. Once the radiotracer has been administered, the scanning part of the device slowly moves over the part of the patient's body that is of particular interest. When the radiotracer is broken down by particular tissues in the body, positrons are emitted during the breakdown process. When positrons are emitted in the body from the breakdown of the radiotracer, gamma rays are produced. The PET scanner can pick up the gamma rays that are emitted, and use this information to compose an image map of the internal tissues. The higher the concentration of gamma rays, the brighter the spot will appear in the PET scan image.

Learn more about when PET scans are used next.

Whitney Alexandra