Nuclear Stress Test
This test helps determine which parts of the heart are healthy and functioning normally and which are not. Before exercising, a very small and harmless amount of radioactive substance is injected into the patient. Then the doctor uses a special camera to identify the rays emitted from the substance within the body. This produces clear pictures of the heart tissue on a monitor. Using this technique, the heart has “hot” and “cold” spots that indicate the areas of heart muscle damage present before, during, and after exercise.
It is typically done for people with unexplained chest pain or to determine the location and amount of injured heart muscle after a heart attack.
Stress thallium scans often involve making two sets of images: one set is taken while the person is at rest (called resting images), and the other is taken after the heart has been stressed either through exercise (treadmill or bike) or by using a medication (both are called stress images). Then the resting images and the stress images are compared.
The medication used in place of exercise either causes healthy arteries (but not blocked ones) to become wider (dilate) or increases the workload on the heart, both of which increase the heart muscle’s need for oxygen and reveal areas of the heart that are not receiving adequate blood flow. Medication stress testing may be done instead of exercise stress testing for people with certain conditions that may make exercise difficult.