PET (positron emission tomography) is a medical imaging technology that uses short-lived radionuclide tracers that are injected in a vein. The most common tracer used is a form of sugar. This is taken up by certain cells; especially cancer cells, but also in normal brain cells and normal heart muscle. This imaging technique is very sensitive for finding certain types of cancers and following their response to treatment.

If you are under a physician's care, you should follow your physician's recommendations for the frequency of having a PET scan. Typically, it is suggested that you have a follow-up scan at least every five years. Regardless of how advanced science becomes, however, it should be noted that a PET scan cannot replace the benefits of a clinical exam and evaluation performed by your physician.

No, there are no side effects to having a PET scan performed. The only pain involved is the needle prick when you receive the radiopharmaceutical injection and it doesn't differ from any other type of injection you might receive in its "pain quotient."

You will have a small injection of a radioactive substance. The injection enables the PET scanner to produce a picture which reveals important information and will assist the research team to learn more about your condition or treatment. What’s the difference between a PET scan and other imaging tests, such as CT and MRI? PET is a way of imaging how the body is functioning; this is different to CT and MRI, which are used to visualize the structure of the body.

The only pain involved is the needle prick when you receive the radiopharmaceutical injection which does not differ from any other type of injection.

Patients should also bring all previous studies, including CT and/orn MR films and reports, as well as their chemotherapy history, including date of most recent treatment, with them. Patients must fast overnight prior to a PET scan. Afternoon patients may eat a light meal six hours prior to exam. Patients should drink water before beginning fast and drink lots of water after beginning fast. Continue to hydrate. Oncology patients must fast overnight, or at least 6 hours prior to PET scan.

Patients undergo PET because their referring physician has recommended it. A radiologist who has specialized training in PET will interpret the images and forward a report to your referring physician. It usually takes one to three days to interpret, report and deliver the results. In order to facilitate interpretation, you may be asked to bring any previous radiological images with you, such as recent CT (CAT) scans or MRI images.

If your doctor has ordered a PET scan for you, it is likely that he or she wants more detailed information about a suspecious or abnormal finding on another test such as a CAT scan or MRI.

Your referring physician will have someone from his or her office contact the USC PET Imaging Center to order the PET procedure you need. Alternatively, you may call the center directly at (213) 342-5940 once instructed by your physician, ask for Monica (mgarfiel@hsc.usc.edu).

Before the scan, you will be injected with a radioactive tracer. The tracer is a compound such as sugar, labeled with a short-lived radioisotope. Once injected, you will be asked to rest for approximately thirty to forty-five minutes while the radioactive compound distributes throughout your body, and is processed by the organs being evaluated. The radiation exposure associated with PET is safe and much lower than that associated with conventional CT scanning.