A nuclear heart scan is a type of medical test that allows your doctor to get important information about the health of your heart. During a nuclear heart scan, a safe, radioactive material called a tracer is injected through a vein into your bloodstream. The tracer then travels to your heart. The tracer releases energy, which special cameras outside of your body detect. The cameras use the energy to create pictures of different parts of your heart.
Nuclear heart scans are used for three main purposes:
- To provide information about the flow of blood throughout the heart muscle. If the scan shows that one part of the heart muscle isn't receiving blood, it's a sign of a possible narrowing or blockage in the coronary arteries (the arteries that supply blood and oxygen to your heart). Decreased blood flow through the coronary arteries may mean you have coronary artery disease (CAD). CAD can lead to angina, heart attack, and other heart problems. When a nuclear heart scan is performed for this purpose, it's called myocardial perfusion scanning.
- To look for damaged heart muscle. Damage may be due to a previous heart attack, injury, infection, or medicine. When a nuclear heart scan is performed for this purpose, it's called myocardial viability testing.
- To see how well your heart pumps blood out to your body. When a nuclear heart scan is performed for this purpose, it's called ventricular function scanning.
Usually, two sets of pictures are taken during a nuclear heart scan. The first set is taken when the heart is beating fast due to you exercising. This is called a cardiac stress test. If you can't exercise, your heart rate can be increased using medicines such as adenosine, dipyridamole, or dobutamine.
The second set of pictures is taken later, when the heart is at rest and beating at a normal rate.
This answer from the National Heart, Lung and Blood Institute has been reviewed and/or edited by Dr. William D. Knopf.