A positron emission tomography (PET) scan is a noninvasive imaging technique that creates 3-D images of your heart, brain and other organs of your body. Your doctor may use a PET scan to reveal how your tissues and organs are functioning and to diagnose cancer, heart disease, dementia or seizures. The scan can identify rapidly growing cells, such as cancer cells. PET scans can also reveal abnormal blood flow in your heart or register activity levels in your brain.
Before your PET scan, you may receive an injection of a small amount of tracer (radioactive glucose) into your vein, or you may inhale or swallow the tracer. After a waiting period, a camera (positron) detects the activity of the tracer in your body and a computer then constructs a 3-D image of the tissue or organs your doctor wants to evaluate. A typical scan takes about two hours, including preparation.
Your doctor may use a PET scan as an alternative to biopsy. At Mayo Clinic, doctors often combine PET scanning with CT scanning to enhance the accuracy of their diagnoses.
A PET scan:
See a video clip of a PET scan showing cancers in the abdomen.