A thallium stress test provides your doctor with information about the blood flow to your heart. The test is performed in Mallinckrodt Institute's nuclear medicine division and is used to determine such problems as cause of chest pain, effects of a heart attack, coronary artery blockage, and effectiveness of some cardiac procedures.
You will be asked to either walk on a treadmill or ride a stationary bicycle. When you feel you have reached your exercise limit, you will receive a small dose of thallium (a radioactive substance). While you are lying down, images of your blood and the thallium will be taken with a special instrument called a gamma camera. Images will be taken immediately after you exercise to show the blood flow to the heart during activity. You then will be asked to lie quietly for about two hours, so additional images can be taken of the blood flow to your heart during resting time.
A normal test shows blood flow through the coronary arteries during activity and during resting time.