PET scans have many uses. PET scans are used to detect cancer and to examine the effects of cancer therapy by showing biochemical changes with the cancer. PET scans of the heart can be used to determine blood flow to the heart muscle and help evaluate signs of coronary artery disease. Combined with a myocardial metabolism study, PET scans differentiate non-functioning heart muscle from heart muscle that would benefit from a procedure, such as angioplasty or coronary artery bypass surgery. PET scans of the brain are sometimes used to evaluate patients who have memory disorders of an undetermined cause; who have suspected or proved brain tumors; or who have seizure disorders that are not responsive to therapy, therefore, are candidates for surgery.
Benefits of a PET scan include:
• Because a PET scan allows for the study of body function, it can help physicians detect alterations in biochemical processes that suggest disease before changes in anatomy are apparent.
• The radioactivity of a PET scan is very short-lived making radiation exposure extremely low. The substance amount is so small that it does not affect the normal processes of the body.
Risks of a PET scan include:
• The radioactive substance may expose the fetus of pregnant patients or the infants of breast-feeding women to the radiation. The risk to the fetus or infant should be considered related to the information gain from the potential result of the PET examination.
What You Need To Know
• Your physician will give you instructions on how to prepare for your specific exam. Typically, no food or drink is allowed after dinner the night before your exam or at least 4 hours before your exam. It is important to follow these instructions to ensure the most accurate diagnostic results.
For your comfort and peace of mind, please be sure to:
• Tell your doctor if you are pregnant or think you might be pregnant, or if you are a nursing mother.
• Wear comfortable clothing.
• Tell your doctor if you are diabetic.
• Take any prescribed medications on the day of your test unless instructed not to do so.
Before the scan, a small amount of radioactive glucose (called a trace) is injected into your bloodstream. Then you are asked to wait 30 - 45 minutes while the injected material is distributed throughout your body. After that time has elapsed, you will be asked to lie on a table that passes slowly through the scanner. The scanner resembles a CT scanner, but has a much larger opening. Some people fall asleep during the scan. Having a PET scan is safe and takes about 2½ hours. It is an outpatient procedure. After the test, you should feel fine and be able to leave immediately. There are no side effects from the injected trace.