A MUGA scan (Multi Gated Acquisition Scan) is a nuclear medicine test to evaluate the function of the heart ventricles. It is also called Radionuclide Angiography. It provides a movie-like image of the beating heart, and allows the doctor to determine the health of the heart’s major pumping chambers. The advantages of MUGA is that it is more accurate than an echocardiogram and it is non-invasive.

From http://en.wikipedia.org/wiki/MUGA_scan