What is the 'stress thallium test'?

See below: A stress thallium test uses a nuclear tracer to visualize blood flow during exercise or chemical stress in a person unable to exercise. The purpose of the test is to uncover artery narrowings that can impede flow when an increased demand for flow is required as in"stress." the test can also give information about the heart's pumping power called the ejection fraction.

A nuclear stress: Test designed to evaluate blood flow during rest and stress conditions. The radioisotope in this case would be thallium.

Shows blood flow : thallium is tagged to red blood cells. The heart is stressed (increase cardiac outpu), then nuclear scanning helps show if there is equal blood flow to all parts of the heart, by detecting the radioactive thallium.