Reported February 2006

BACKGROUND: A team of researchers has demonstrated for the first time that an experimental radioactive compound can show images of heart damage up to 30 hours after a brief interruption of blood flow and oxygen. The discovery may help ER physicians and private doctors determine whether a patient's chest pain -- which may have subsided hours earlier -- is related to heart disease or to a less serious condition, such as indigestion.

HOW IT WORKS: Nuclear medicine combines computers, detectors and radioactive substances called radioisotopes to produce images of blood flow and biochemical functions in the heart and other organs. The radioactive tracer used in this study links a fatty acid to a radioisotope that is injected into the patient. The heart normally uses fatty acid as its primary fuel source for energy. But when arteries narrow or become clogged, or when the heart works harder during strenuous exercise, less blood can flow to the heart and slow down or halt the way the body uses fatty acid. This condition is called myocardial ischemia and is a common cause of chest pain. In response, the heart switches from fatty acid to glucose as an energy source. The new tracer test targets the signs of this disturbance and apparently remembers the imprint of an episode of reduced blood flow long after it occurs.

ABOUT RADIOISOTOPES: An isotope is a subset of a chemical element that has the same number of protons in the atomic nucleus, but a different number of neutrons. Certain combinations of protons and neutrons make the atoms unstable; these are called radioisotopes. The atoms will become stable over time by emitting gamma radiation – a process known as radioactive decay. Certain short-lived isotopes are useful for nuclear diagnostic imaging because they can be linked to chemical compounds associated with specific physiological processes in the body. These radioactive tracers emit gamma rays from within the body, which can then be detected by a special gamma ray camera. A computer turns those signals into an image that can be viewed by a physician on a monitor to search for signs of an abnormal condition.

REDUCE YOUR RISK: Causes of chest pain can vary, from heartburn and stress, to more serious heart conditions. You can reduce your risk of the latter by following these tips:

• Don't smoke
• Maintain a healthy weight
• Eat foods low in salt and fat, but high in fiber
• These include vegetables, whole grains and fruits
• Exercise three or more times a week
• Find ways to reduce and control stress in your life

The American Association of Physicists in Medicine contributed to the information contained in the TV portion of this report.

If you would like more information, please contact:

University of Maryland Medical Center
22 South Greene Street
Baltimore, MD 21201
(800) 492-5538
TDD: (410) 328-9600