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Thallium and sestamibi stress tests

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Thallium and sestamibi stress tests

Alternative Names:

Sestamibi and thallium stress tests; MIBI stress test

Definition:

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Thallium and sestamibi stress tests are nuclear imaging methods that provide a view of the blood flow into the heart muscle. The thallium and sestamibi tests are also called “MIBI stress test” and “myocardial perfusion scintigraphy”, and are used to evaluate how well your heart is perfused (supplied with blood) at rest as compared with activity.

During these tests, heart images can be obtained because the patient receives an injection of a substance that is labeled with a radioactive marker or radiotracer to make it visible in the bloodstream. These substances are also called radiopharmaceuticals, and include thallium-201 and technetium-99m MIBI or sestamibi.

In comparison to the standard treadmill stress test, thallium and sestamibi stress tests are more accurate and provide additional information.

How the test is performed:

In a special room or lab at a medical center, you will be instructed to exercise as hard as you can on a treadmill or bicycle. If your doctor considers that exercise is not safe for you, or that you may be unable to exercise enough because of orthopedic problems, then you will be given an intravenous medication that will challenge your heart as if you were exercising.

When you reach your maximum level of exercise, a nurse will inject in your vein a small amount of a radioactive substance (radiotracer), either thallium or sestamibi. The radiotracer will travel in the bloodstream and, through the coronary arteries, will enter into the heart muscle as you complete your exercise session.

After you finish exercising, you will lie down on a special table under a bulky camera called a gamma camera. The gamma camera can scan your heart and detect the radiotracer in it. The distribution of the radiotracer in your heart will be processed by a computer to create pictures of your heart. The first pictures are made shortly after the exercise test, to show the circulation of blood to your heart during exercise. This is the part considered "a stress test" and is the most challenging for your heart.