A nuclear scan is a test that uses a radioactive substance (known as a tracer) to produce images of the heart muscle. When combined with an exercise test, the nuclear scan provides information that cardiologists can use to determine if areas of the heart are not receiving enough blood.

During a nuclear scan, a radioisotope called Sesta MIBI is injected into the circulatory system and tracked as it passes through the heart. The amount of radioactive material used is so small that it poses no health threat to the patient and produces no side effects.

The first phase of the study is done as the patient walks on a treadmill and his or her heart begins to work harder. (For those patients unable to walk on a treadmill, a drug may be used to stimulate the effects of exercise.) During this part of the test the patient is injected with a very small amount of the tracer through an intravenous line.

A cardiologist monitors the patient and watches the EKG that is done concurrent with the test. When the stress portion of the test concludes, the patient is "imaged" in the Nuclear Medicine Section of CMMC's Radiology-Medical Imaging Department. Later the patient returns for a second injection and another set of images are taken. These images show the heart at rest.

Comparison of the images show the difference in the amount of blood the heart receives under stress and the amount it receives while at rest, allowing the cardiologist to detect blockages in coronary arteries that supply oxygen-rich blood to the heart muscle.