A PET, or positron emission tomography, scan is a type of imaging technology that detects radioactivity in the body and renders an image, explains the American Cancer Society. Physicians can use the test to locate cancerous cells in the colon and determine whether the disease is spreading.Continue Reading
PET scans can help doctors evaluate the severity of colon cancer and the projected effectiveness of treatments such as chemotherapy, according to Medical News Today. To administer the test, doctors must inject a patient with a special radioactive substance, such as fluorodeoxyglucose, which is introduced along with a natural chemical, or radiotracer, such as water or glucose. The radiotracer breaks down as it travels through the body, releasing energy-emitting particles known as positrons. The PET scanner detects positron energy and translates the findings into a three-dimensional color image doctors can view on a computer.
Since cancer cells absorb more of the radioactive drug than other surrounding tissues, they are rendered more clearly in a PET scan's images, notes the American Cancer Society. During the test, the patient lies on a table surrounded by the scanner camera, and the test typically lasts about 30 minutes. PET scans produce images with less detail than other imaging technologies, such as CT scans, so they are often used in conjunction with other diagnostic procedures. For example, physicians may perform a blood test and a colonoscopy to confirm the existence of colon cancer and rely on PET scans to periodically track its progress.Learn more about Cancer