MUGA scan

A MUGA scan (Multiple Gated Acquisition Scan) is a noninvasive nuclear medicine test to evaluate the function of the heart. 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.

To perform the test, stannous (Tin) ions are injected into the patient's bloodstream. The stannous ions make the red blood cells 'sticky' and a subsequent intravenous injection of the radioactive substance, Technetium-99m-pertechnetate, labels the red blood cells in-vivo. With an administered activity of about 800 MBq, the effective radiation dose is about 8 mSv. The patient is placed under a gamma camera, which detects the low-level gamma radiation being given off by technetium-99m. As the gamma camera images are acquired, the patient's heartbeat is used to 'gate' the acquisition. The final result is a series of images of the heart (usually sixteen), one at each stage of the cardiac cycle.

The resulting images show the blood pool in the chambers of the heart and the images can be analyzed on a computer to calculate the ejection fraction of the heart together with other useful clinical parameters. This scan gives an accurate and reproducible means of measuring and monitoring the ejection fraction of the left ventricle.

For a patient that has had a heart attack, or is suspected of having another disease that affects the heart muscle, this scan can help pinpoint the position in the heart that has sustained damage as well as assess the degree of damage.