Using a PET scan for cancer diagnosis is a relatively common procedure. A PET scan is a form of imaging test similar to an MRI or CT scan. Also known as a positron emission tomography scan, the PET scan uses a radioactive substance to pinpoint the exact location of cancer cells. Neither a CT scan nor an MRI are used for diagnosing active tumors.
Using a PET scan for cancer diagnosis is a multiple step process. The person receiving the PET scan must take a small amount of radioactive material. This can be in the form of an intravenous injection, or be inhaled or taken orally. The amount of radioactive material is very small, and is not a concern for most individuals. A PET scan for cancer diagnosis is not typically recommended for women who are breastfeeding or pregnant.
Once inside the body, the radioactive material is attracted to and will cluster around an area that has a large amount of cellular activity. Many types of cancer cells have this characteristic, particularly cancers of the brain, breast, esophagus, cervix, colon, thyroid, lung, and pancreas, as well as lymphoma and melanoma. The patient then enters the PET scanner, which takes images of the targeted area.
The doctor will review the images from the PET scan to determine if there are cancer cells present, and how widespread they are. Physicians will often perform a follow-up PET scan on people undergoing treatment for cancer. These PET scans allow the doctor to determine how well the patient's cancer is responding to treatment. After cancer treatment is complete, the healthcare provider may want the patient to undergo periodic PET scans to determine if the cancer has recurred.
The major benefit of using a PET scan for cancer diagnosis is that it allows the patient to receive an early diagnosis of cancer, when the cancer is most easily treated. It also makes it possible to scan the entire body for cancer cells. This allows the oncologist to determine the extent of the cancer, and to make the best possible decisions about cancer treatment.
PET scans are widely used in cancer diagnosis, but they have other uses as well. They help diagnose neurological conditions and heart disease. Regardless of the reason the PET scan is used, it is possible to receive a false positive from the test. The radioactive material is attracted to any area with a high level of cellular activity, so less serious conditions may show up as bright spots on the scan. The PET scan is only one part of the strategy physicians use to diagnose cancer and other diseases.