Nuclear stress testing is a test done in order to find areas of decreased blood flow to the heart at times when the heart is stressed. A radioactive isotope is injected into the blood stream prior to having a patient exercise. Once the patient has reached his/her target heart rate, a nuclear scan is performed which looks at the concentration of the isotope in various parts of the heart. Areas which appear light in color on the scan do not receive enough blood flow during exercise are likely to be served by a stenotic vessel. Testing is repeated after several hours while the patient is at rest, to determine extent of disease. This test is also known as a stress thalium test.
