A thallium or technetium sestamibi scan estimates the amount of blood reaching the heart muscle during rest and exercise. It is typically done to determine the cause of unexplained chest pain or to determine the location and amount of injured heart muscle after a heart attack.
For this test, a radioactive substance called a tracer is injected into a vein in your arm. The tracer is often thallium or technetium sestamibi (Cardiolite). Once the radioactive tracer has been injected into the bloodstream, a gamma camera is used to view the amount of the tracer that reaches the heart muscle. As the tracer moves through the heart muscle, areas that have good blood flow absorb the tracer. If an area of heart muscle does not adequately absorb the tracer, it means either that the blood flow is severely reduced (ischemia) or there has been a previous heart attack. The tracer remains in the body temporarily (less than a day) before it is eliminated, usually in the urine or stool (feces).
Stress thallium scans often involve making two sets of images: rest images and stress images. Rest images are taken while the person is resting and stress images are taken after the heart has been exercised (treadmill or bike) or by using a medication called adenosine, dipyridamole (Persantine), or dobutamine (Dobutrex). Then the resting images and the stress images are compared. Medication stress testing may be done instead of exercise stress testing for older adults and people with conditions that may make exercise difficult, such as those who are obese or those with COPD, peripheral vascular disease, spinal cord injury, arthritis, or multiple sclerosis.
Paraphrased from: web MD site. Visit their site for in depth information. |