The PET scan or positron emission tomography is a type of medical test that takes pictures of body's internal organs. According to the Mayo Clinic, this scan allows health-care providers to visualize soft tissues and organs such as the brain and heart to determine how they are working.
How It Works
To start a PET scan, a radioactive chemical is injected into a blood vessel in the arm. This chemical flows through the body and attaches to the organs being studied. This chemical gives off energy that can be detected and converted by a computer into three-dimensional pictures. The health-care provider can then study the organs and tissues to assess for problems. The radioactive substance can also be inhaled or swallowed depending on the area of concern.
Why It's Performed
According to the Mayo Clinic, a PET scan works well in diagnosing conditions such as cancer, heart disease and brain disorders. PET scans can verify how far cancer cells have spread, if cancer treatments are working and if the cancer has returned. Not all types of cancer can be revealed by the PET scan. The most common cancers monitored by PET scans are: brain, breast, cervical, colon, esophageal or throat, lung, lymphoma, melanoma or skin, pancreatic and thyroid. The PET scan can easily identify a decrease in blood flow related to heart disease and abnormal brain conditions such as tumors, memory and seizure disorders.
Risks
According to the Cleveland Clinic, the amount of radioactive chemical used for the test is small and does not disturb the natural functioning of the body. The chemical can harm an unborn child and breastfeeding infants.
The Procedure
After the radioactive chemical is given, the patient must lie flat on a movable board or table. The table will slowly slide into the PET scanner which is round with a hollow center. The procedure is usually completed as an outpatient procedure and will take anywhere from one to two hours to complete. According to the Mayo Clinic, the patient will not feel any pain during the process but will be asked to remain extremely still.
Results
A specially trained radiologist will read the PET scan results and provide a report to the primary health-care provider. The interpretation process may take up to three days to complete.
How It's Different
The PET scan differs from similar exams such as CT scans and MRIs because it can find abnormalities at the cellular level. Many disorders such as cancer start at this basic level. The PET scan is able to determine a change in condition earlier than the other scans due to this quality.
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