A PET or positron emission tomography scan is a specialized CT procedure used most often to image cancer and examine the effects of cancer therapy by characterizing biochemical changes in the cancer. These scans can be performed on the whole body. PET scans of the heart can be used to determine blood flow to the heart muscle and help evaluate signs of coronary artery disease. PET scans of the heart can also be used to determine if areas of the heart that show decreased function are alive rather than scarred as a result of a prior heart attack, also called a myocardial infarction.
Combined with myocardial perfusion studies, PET scans allow differentiation of nonfunctioning heart muscle from heart muscle that would benefit from a procedure such as angioplasty or coronary artery bypass surgery, which would reestablish adequate blood flow and improve heart function. PET/CT scans of the brain are used to evaluate patients who have memory disorders of an undetermined cause, suspected or proven brain tumors or seizure disorders that are not responsive to medical therapy and are therefore candidates for surgery.
How Should You Prepare for a PET/CT Exam?
- Eating: The day before your exam, follow a low carbohydrate, high protein diet, avoiding sweets, breads, pasta, rice, and cereals. Do not eat anything for at least six hours prior to your exam. Most medications do not interfere with this test and can be taken as usual.
- Diabetic Patients: For the test to be effective, it is important for your blood sugar levels to be 180 or lower. When you schedule your appointment, please tell us if you are diabetic so we can provide special instructions.
- Clothing: Wear warm, comfortable, athletic-style clothing without metal snaps or zippers. We might ask you to wear an exam gown during the study because snaps, zippers, hooks, fasteners, belt buckles, and other metal objects on your clothing affect the PET/CT. Remove all jewelry before the test, as well.
- Exercise: Do not exercise within 24 hours of your scheduled PET scan appointment.
What to Expect During a PET/CT Scan
Similar to a CT, you will be placed securely on a comfortable padded table. The technologist will place an IV catheter into your hand or arm and inject a radiotracer. There are no side effects associated with the injection. It will take approximately 60 minutes for the radiotracer to travel through your body and get absorbed by the specific organ or tissue being studied. We will ask you to rest quietly, avoid excessive movement and remain silent. We might also ask you to drink contrast material that will localize in the intestines and help the radiologist interpret your study. After the procedure, you will be free to resume your normal daily activities.