Also known as a nuclear ventriculogram, a multi-gated acquisition (MUGA) scan is a form of radionuclide imaging that provides the physician with a comprehensive view of blood flow and the function of the lower chambers of the heart ventricles.

During a MUGA scan, very small amounts of a radioactive isotope called tracer are injected into the bloodstream through an intravenous (I.V.) line. This substance emits weak gamma rays that are picked up by a special gamma camera. As the tracer travels through the heart, the gamma camera takes multiple pictures of the heart, allowing the physician to gain a very accurate picture of the lower ventricles. MUGA tests may also be conducted while the patient is exercising, which will yield information about how the heart performs under mild physical stress.

People may experience some slight discomfort from the insertion of the needle for the IV line,  usually in the crook of the arm. Otherwise, this test is painless. If the physician has also ordered an exercise component of the test, some preparation will be necessary, such as wearing the appropriate clothes and shoes for exercising.

Although the tracer is flushed harmlessly from the bodies of most people in about 48 hours, there are some people (e.g., pregnant or nursing women) who should not have a radionuclide test. People are encouraged to discuss with their physician any concerns they may have about radiation.