The MUGA scan (Multiple Gated Acquisition scan) is an extremely useful noninvasive tool for assessing the function of the heart. The MUGA scan produces a moving image of the beating heart, and from this image several important features can be determined about the health of the cardiac ventricles (the heart’s major pumping chambers). Several important features of cardiac function can be measured from the MUGA scan. If a patient has had a heart attack, or any other disease that affects the heart muscle, the MUGA scan can localize the portion of the heart muscle that has sustained damage, and can assess the degree of damage. But more importantly, the MUGA scan gives an accurate and reproducible means of measuring and monitoring the ejection fraction of the cardiac ventricles.