What should I expect during a nuclear heart scan?

Nuclear imaging tests measure the pattern of blood flow to the heart muscle. Nuclear imaging is a painless procedure. The only thing you'll really feel is the placement of the intravenous (IV) for injection of the radionuclide before the scan. And don't worry -- the radionuclide rapidly leaves your body, and the radiation exposure poses very little risk.

A nuclear imaging study can take less than an hour or up to several hours, depending on whether it is coupled with a stress test.
Many, but not all, nuclear medicine centers are located in hospitals. A doctor who has special training in nuclear heart scans—a cardiologist or radiologist—will oversee the test. (Cardiologists are doctors who specialize in diagnosing and treating heart problems. Radiologists are doctors who specialize in diagnostic techniques such as nuclear scans.)
Before the test begins, the doctor or a technician will use a needle to insert an intravenous (IV) line into a vein in your arm. Through this IV line, he or she will put the radioactive tracers into your bloodstream at the right time. You also will have EKG (electrocardiogram) patches attached to your body to check your heart rate during the test.
If you're having an exercise stress test as part of your nuclear scan, you will walk on a treadmill or pedal a stationary bicycle, while attached to EKG and blood pressure monitors.
You will be asked to exercise until you're too tired to continue, short of breath, or having chest or leg pain. You can expect that your heart will beat faster, you will breathe faster, your blood pressure will increase, and you will sweat. Report any chest, arm, or jaw pain or discomfort; dizziness; lightheadedness; or any other unusual symptoms.
If you're unable to exercise, your doctor can give you medicine to make your heart beat faster. This is called a chemical stress test. The medicine used may make you feel anxious, sick, dizzy, or shaky for a short time. If the side effects are severe, other medicine can be given for relief.
Before the exercise or the chemical stress test stops, the tracer is injected through the IV line. The nuclear heart scan will start shortly after the exercise or chemical stress test. You will be asked to lie very still on a padded table.
The nuclear heart scan camera, called a gamma camera, is enclosed in a metal housing. The part of the camera that detects the radioactivity from the tracer can be put in several positions around your body as you lie on the padded table. For some nuclear heart scans, the metal housing is shaped like a doughnut and you lie on a table that goes slowly through the doughnut hole. The computer used to collect the pictures of your heart is nearby or in another room.
This answer from the National Heart, Lung and Blood Institute has been reviewed and/or edited by Dr. William D. Knopf.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.