Positron Emission Tomography (PET)
Positron emission tomography, also called PET imaging or a PET scan, is a diagnostic examination that involves the acquisition of physiologic images based on the detection of positrons. Positrons are tiny particles emitted from a radioactive substance administered to the patient. The subsequent views of the human body developed by this technique are used to evaluate a variety of diseases.
- PET scans are used most often to detect cancer and to examine the effects of cancer therapy by characterizing biochemical changes in the cancer.
- PET Scans can be performed on the whole body, or just a limited area.
- PET scans of the brain are used to evaluate patients who have memory disorders of an undetermined cause; who have suspected or proven brain tumors; or who have seizure disorders that are not responsive to medical therapy and, therefore, are candidates for surgery
PET Cardiac Imaging
- 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 due to a prior heart attack, called a myocardial infarction.
- Combined with a myocardial perfusion study, PET scans differentiate 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.
Patient Preparations
You should wear comfortable, loose-fitting clothes. You should not eat for four (or more) hours before the scan. You will be encouraged to drink water. Your doctor will instruct you regarding the use of medications before the test. A nurse or technologist will take you into a special PET examination room where you will lie down on an examination table and be given the radioactive substance as an intravenous injection. Some patients, specifically those with heart disease, may undergo a stress test in which PET scans are obtained while they are at rest, and again after undergoing the administration of a pharmaceutical to alter the blood flow to the heart.
Usually, there are no restrictions on daily routine after the test, although you should drink plenty of fluids to flush the radioactive substance from your body. Depending on the type of PET Exam, the total exam time may take 1 hour or more. If you are pregnant, think you may be pregnant, or are breast feeding, inform the technologist before you begin your procedure.
