The tracer is injected into your blood and travels to your heart. Nuclear heart scans use single photon emission computed tomography (SPECT) or cardiac positron emission tomography (PET) to detect the energy from the tracer to make pictures of your heart. This imaging test can detect if blood is not flowing to parts of the heart and can diagnose coronary heart disease. It also can check for damaged or dead heart muscle tissue, possibly from a previous heart attack, and assess how well your heart pumps blood to your body. Compared to SPECT, PET takes clearer pictures; however, either option may be used.
A nuclear heart scan may be performed in a medical imaging facility or hospital. Your heart will be monitored during this test with an electrocardiogram (EKG). Two sets of pictures will be taken, each taking 15 to 30 minutes. The first set of pictures is taken right after an exercise or medicine stress test because some problems can be detected only when the heart is working hard or beating fast. If you are not able to exercise, your doctor may give you medicine to increase your heart rate. Shortly after the stress test, the tracer will be injected into a vein in your arm. You may bruise at the injection site. You will lie still on a table that slides through a tunnel-like machine as the first set of pictures is taken. The second set of pictures will be taken on either the same day or the next day after your heartbeat has returned to a normal rate.
Nuclear heart scans have few risks. The amount of radiation in this test is small. In rare instances, some people have a treatable allergic reaction to the tracer. If you have coronary heart disease, you may have chest pain during the stress test. Medicine can help relieve your chest pain. Talk to your doctor and the technicians performing the test about whether you are or could be pregnant. If the test is not urgent, they may have you wait to do the test until after your pregnancy. Let your doctor know if you are breastfeeding because radiation can pass into your breast milk. If the test is urgent, you may want to pump and save enough breast milk for one to two days after your test, or you may bottle-feed your baby for that time.
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The National Heart, Lung, and Blood Institute (NHLBI) leads or sponsors many studies aimed at preventing, diagnosing, and treating heart, lung, blood, and sleep disorders.