Thallium-201 exercise myocardial perfusion scintigraphy, a new, non-invasive screening method, serves to visualize stress-induced ischemic regions and scarred tissue. As compared to the exercise electrocardiogram, the method shows higher sensitivity and specificity in detecting coronary artery disease. Moreover, it makes it possible to localize the predominant defects. Even though myocardial scintigraphy cannot replace coronary arteriography in establishing the precise morphologic situation of the coronary arteries, it is of help in deciding whether an arteriogram should be carried out or not. Thus, important indications for myocardial stress scintigraphy are atypical chest pain and an abnormal electrocardiogram without pain. Furthermore, the method is useful for evaluating patients with uninterpretable electrocardiograms during exercise, and in assessing the outcome of coronary artery bypass surgery.