Since coronary artery disease often first manifests as sudden death or myocardial infarction before symptoms develop, the early detection of disease may identify patients at risk for an acute event. Stress redistribution thallium-201 scintigraphy provides a useful, noninvasive method for assessing the presence of CAD as well as for evaluating the extent of disease. The principles and methods of thallium scintigraphy are described herein in addition to its clinical application. The availability of noninvasive thallium-201 scintigraphy has added to the physician's ability to accurately diagnose CAD, to objectively evaluate the effects of coronary artery bypass surgery, and to assess patients with acute myocardial infarction.