The thallium stress test identifies areas of the heart muscle that receive reduced blood flow from narrowed or blocked coronary arteries. During the test, thallium is injected into the bloodstream. Heart muscle cells collect the thallium in the bloodstream. If blood flow is reduced through one of the coronary arteries, then the muscle cells that are supplied by that artery do not collect as much thallium as muscle cells that receive normal blood flow. A special camera is used to detect thallium in the heart muscle and a computer constructs images of the heart. The images show areas that receive reduced blood flow.

Examples:

• Thallium stress test
• Gamma camera measures radiation given off by the thallium
• Thallium heart scan image