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PET Imaging
What is PET Imaging?
Positron Emission Tomography (PET) is a sophisticated new imaging technique that provides a comprehensive and unique picture of metabolic activity within the body. Using PET, physicians can locate and identify disease, particularly cancer, often before it is visible by other imaging techniques. PET can have a major impact on the treatment of cancer by identifying if a cancer has spread to other locations in the body before it is visible by other imaging techniques. Clinical studies have shown that PET alters patient staging and treatment management in up to 40% of cancer cases.
Who should get a PET scan?
Your primary care physician or referring specialist will determine if a PET scan is appropriate for your care. PET is most commonly used for cancer diagnosis and staging. PET is safely used for both adult and pediatric patients. Pregnant or nursing women are usually not imaged with PET.
How does PET work?
PET is similar to a CT scan in that cross-sectional images of the body are obtained. CT uses a rotating external x-ray beam to determine density within the body. PET uses an injected radioactive substance, called a radiopharmaceutical, and measures the distribution of this substance within the body with a ring-shaped detector array that resembles a CT or MR scanner. Unlike conventional radiopharmaceuticals, PET uses positron emitters, which are very short-lived isotopes that have a number of practical advantages over conventional isotopes, including higher resolution pictures and lower radiation dose. The most common PET radiopharmaceutical is 5-fluoro deoxyglucose, or FDG. FDG is a glucose analog that localizes to sites of high glucose metabolism. Normal accumulation of FDG is seen in the heart, brain, and other highly metabolically active organs. Rapidly dividing tumors, including most cancers, also tend to accumulate FDG, which forms the basis of tumor imaging.
How much radiation will I receive from a PET scan?
A typical PET scan will produce a whole-body radiation exposure about equivalent to two chest x-ray exams.
Is PET painless?
Absolutely.
How do I prepare for my PET scan?
Overnight fasting is required because the amount of sugar in your body affects the test results. Nondiabetic patients should fast overnight or for at least six hours before the exam. Diabetic patients should not fast and may eat regular low-fat meals and take their usual insulin dose. Everyone should drink plenty of water before and during their fast.
Exercise should be avoided for three days prior to the exam. Your muscles need to be in a resting state when having a PET scan.
What happens on the day of my PET scan?
After arrival at the hospital radiology department, you will be escorted to a prep room. You will receive an intravenous injection of the radiopharmaceutical FDG. You will be asked to rest quietly while the FDG circulates, and then moved into the PET scanner. You will be asked to lie still on your back for the duration of the scan. The scan itself takes between 30 and 60 minutes, and the total time required for the study is about two hours.
Will my insurance cover PET?
Most insurance companies provide PET coverage for specific indications, varying by the insurer. It is important for you or your referring doctor to contact your insurer regarding coverage. Your referring doctor may be able to assist with referrals, pre-authorization, or other specific requirements. In instances where medical insurance does not cover the PET examination, the average cost is $3000.
How can I learn more about PET imaging?
To learn more about PET, visit: http://www.radiologyinfo.org/content/petomography.htm
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