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Patient Instructions

Patient Information

The power of PET

Positron Emission Tomography ("PET") is a revolutionary diagnostic tool that provides diagnostic information that no other imaging test can provide. PET works by creating powerful images of the biological functions of the human body to reveal disease states. To create these images, a short-lived substance, known as FDG, is administered to the patient. The PET scanner records the signals these FDG tracers emit as they circulate through the human body and collect in the various organs targeted for examination. A computer reassembles the signals into actual images, resulting in pictures which show biologic organ function and detects possible disease.

How is PET different from other imaging modalities?

While anatomical imaging modalities like CT and MRI are focused on structural anatomy, PET evaluates the chemical and physiological changes related to metabolism. Since metabolic changes occur long before structural damage to tissue is evident, PET allows for the detection of disease that other imaging modalities are incapable of detecting. In many instances, early detection and treatment can have a major impact on the outcome of treatment. Also, a single PET study can scan the entire body. This can be a crucial advantage in many instances, especially in oncology, where additional tumors and the spread of disease are sometimes discovered. The replacement of multiple tests is also of benefit to patients and physicians, as the extent of disease is established faster, with greater confidence and at less cost.

The key benefits of PET are:

• Safe, non-invasive diagnostic procedure
• Detailed diagnostic information, not available from other tests (like CT, MRI)
• Determines whether a tumor is malignant
• Definitively determines whether cancer has spread to other organs
• Shorter time frame for definitive diagnosis
• Early detection of disease with fewer invasive diagnostic procedures
• Precise staging of the disease and better monitoring of cancer recurrence
• More effective tracking of the results of chemotherapy and radiotherapy
• Can reduce or eliminate ineffective and unnecessary treatment, such as some surgeries
• Contributes to a lower overall cost of care

How accurate is PET?

PET is very accurate in showing the presence or spread of many malignant tumors. For example, it is more accurate in detecting the spread of lung cancer and colon cancer than any other imaging method currently available. A high degree of accuracy has also been demonstrated in evaluating recurrent breast cancer, melanoma, lymphoma, ovarian cancer, pancreatic cancer and tumors of the head and neck. A large body of literature indicates that FDG-PET scanning is useful to differentiate malignant from benign tumors, as well as to determine the extent of disease and to stage cancer. This is of paramount importance to guide physicians to the best therapeutic approach, i.e., chemotherapy vs. radiation or radiation vs. surgery. In up to 15% of patients, PET detects otherwise unsuspected spread of disease, thereby altering the treatment strategy. PET is also unique in its ability to differentiate between residual scar tissue, radiation necrosis and tumor recurrence. It may also be useful in assessing the patient's response to a given therapeutic regimen.

What will I experience during the exam?

A PET scanner is about the same size and dimension as a CT scanner. You will be asked to lie on your back and remain still while you are moved in and out of the scanner. The exam should last approximately 45 minutes. The scan itself causes no pain. You will be able to communicate freely with the technologist and are welcome to enjoy your favorite music on either a tape or CD. About an hour prior to the exam, a small amount of labeled glucose (FDG) will be administered through a vein in your hand or arm. The small amount of radiation you will receive is similar to that of other radiological procedures. It should not cause any side effects and will dissipate by the time you leave the center.

What should I do after the exam?

Following the PET scan, you are asked to drink as much fluids as possible to assist in the rapid dissemination of the tracer from the body. Patients are generally able to drive and resume normal activities immediately after the examination.

Will insurance and Medicare pay for a PET scan?

Yes, most insurance companies, including Medicare, reimburse for PET procedures. Patients should contact their insurance companies directly to learn about benefits. Please ask your Southwest PET/CT Institute representative for a summary of current coverage policies.

For more information on clinical uses of PET please see our Referring Physician Information