What is a PET scan?

A PET scan, or positron emission tomography scan, is a procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body.

Positron emission tomography (PET) scanning is a type of imaging test that aids doctors in determining how glucose tissues and organs are using. Cancer and other metabolically active tissues such as the heart and brain utilize higher amounts of glucose.

A PET scan is a three-hour procedure used for staging of cancer, says Beverly Lustig, Diagnostic Imaging Manager with Good Samaritan Hospital. Learn more in this video.

Positron emission tomography is a type of nuclear imaging that can evaluate heart function. PET scans can be used to look for coronary artery disease by examining how blood flows through the heart; it can evaluate damage to heart tissue after a heart attack. Your physician can use this information to determine the best course of treatment for you.

Dr. Ajay K. Sahajpal, MD
Transplant Surgeon

A PET scan is a positron emission test and is a nuclear medicine study typically used to locate or identify cancers. It occurs by using radio labeled sugar (FDG or flurodeoxyglucose, a glucose analog), which ideally go to actively dividing tissues or metabilically active tissues, such as tumors. Infections can mimic this and "light" up on a PET scan.

A PET scan can be "fused" with a CT or MRI to better enhance images and overlap with those to provide tumor localization.

Unlike CT and MRI scans that provide images of structures in the body, PET scans show chemical changes related to metabolism or body activity. Before a PET scan, a patient will receive an injection of a small amount of a radioactive drug. All tissues absorb some of this drug—called an isotope—but cancerous cells are hypermetabolic, meaning they absorb greater amounts, which enables them to be seen on the scan. PET is used to locate cancerous tumors and to see if the disease has spread to other parts of the body.

Research indicates that combining the PET images into the images provided through CT scanning provides the best of both technologies. This procedure is particularly effective for diagnosing the original cancer site as well as any spread to nearby lymph nodes or more distant sites in the body.

Dr. Vijay Nuthakki, MD
Cardiothoracic Surgeon

PET stands for positron emission tomography. A patient is injected with a radio tracer commonly attached to a glucose molecule and this will be taken up by active sites in the body such as the brain and heart. The glucose is also taken by sites of cancer, infection or inflammation. Most commonly the images are "fused" with CT scan images to specify anatomic sites of activity. Therefore, the PET scan provides "functional anatomy."

PET scans are tests used to diagnosis tumors that are cancerous, such as some ependymomas. In this test, sugar that contains a safe level of radioactive material is injected into a vein of the person being tested. Sugar is used for energy by all cells of the body, and very active cells (such as cancer cells) use more sugar than other cells. Because of this, the radioactive sugar injected into the person builds up around cancer cells. The PET scanner is then used to take pictures of the inside of the body that show if areas with high sugar levels exist, thereby suggesting cancerous cells.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.