GENERAL  NUCLEAR  MEDICINE


Nuclear medicine involves the use of small amounts of radioactive materials (or tracers) to help diagnose and treat a variety of diseases. Nuclear medicine determines the cause of the medical problem based on the function of the organ, tissue or bone. This is how nuclear medicine differs from an x-ray, ultrasound or other diagnostic test that determines the presence of disease based on structural appearance.

(The image at right shows myocardial perfusion scintigraphy.)

Millions of nuclear medicine tests are performed each year in the United States alone. Nuclear medicine tests (also known as scans, examinations, or procedures) are safe and painless. In a nuclear medicine test, the radioactive material is introduced into the body by injection, swallowing, or inhalation. Different tracers are used to study different parts of the body. The amount of tracer used is carefully selected to provide the least amount of radiation exposure to the patient but ensure an accurate test. A special camera (scintillation or gamma camera) is used to take pictures of your body. The camera does this by detecting the tracer in the organ, bone or tissue being imaged and then records this information on a computer screen or on film.

Nuclear scans have many uses, including the following: to detect tumors and other abnormalities of the bones, brain, gallbladder, kidneys, thyroid gland, and many other organs; to assess blood flow to areas of the heart, brain, and other organs; to pinpoint areas of gastrointestinal bleeding; to observe how long it takes for the stomach to empty, or to confirm reflux of stomach contents into the esophagus; and to determine the life span of red blood cells and detect various metabolic abnormalities.

Nuclear scans are based on the principle that specific radionuclides will be absorbed by healthy tissue at a certain rate over a specific period of time. Marked deviations from what is normal indicate possible disease. In a nuclear bone scan, for example, an unusually high absorption of technetium MDP may indicate a tumor, inflammation, or a fracture.

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