FDG-PET Protocols

PET, or positron emission tomography, is a scanning process based on metabolic activity and organ function. Useful in diagnosis of disorders affecting the heart, lungs, brain, bones and liver, the PET scan can provide important information for a physician determining a course of treatment for a patient. Combined with an FDG tracer, PET scans are very helpful in diagnosing cancer.

FDG Tracers

• PET scans are designed to detect fast-growing masses. Because cancers require energy for rapid growth, a PET scan with an FDG tracer can be used to detect cancers. An FDG tracer is a glucose molecule that has been tagged with a radioactive molecule known as FDG. The radioactive glucose is administered intravenously in minuscule amounts. When it is taken in by a cancer, the PET scan can monitor it and thus the cancer can be identified. The radioactive glucose only remains in the patient's body for about two hours and causes no harm to the patient.

Before the PET Scan

• Patients are generally advised not to eat or drink anything for four to six hours prior to the PET scan. Because carbohydrates break down into sugars, it is best not to eat breads, pastas, rice, cereals and sweets for the last meal prior to the scan; foods high in protein and low in carbohydrates are a better option. Patients should also avoid caffeine, tobacco and rigorous workouts the day before the exam. Pregnant women are generally not given PET scans.

PET Scan Procedure

• An IV is inserted into the hand of the patient and the radioactive glucose is administered. The glucose is sterile and safe for human administration intravenously. After waiting for about an hour for the glucose to distribute throughout the body, the patient is asked to lay down on a table. The scanning process takes only a few minutes and is completely painless.

After the Scan

• Soon after the procedure, the patient is discharged and sent home. There are no side effects to a PET scan. The radioactive glucose is quickly excreted by the patient's body and there is no risk of radiation exposure to family members. The results of the PET scan are read by a radiologist and delivered to the physician.