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Nuclear Medicine Nuclear scans make pictures based on the body’s chemistry rather than on physical shapes and forms (as is the case with other imaging tests). These scans use substances called radionuclides (also called tracers or radiopharmaceuticals) that release low levels of radiation. The amount of radioactivity used is very small and not known to cause harm. Body tissues affected by certain diseases, such as cancer, may absorb more or less of the tracer than normal tissues. Special cameras pick up the pattern of radioactivity to create pictures that show where the material travels and where it collects. These scans show some internal organ and tissue problems better than standard x-ray images. If cancer is present, the tumor may show up on the picture as a “hot spot” − an area of increased tracer uptake. Depending on the type of scan done, the tumor may instead be a “cold spot” − a site of decreased uptake. Nuclear scans are used to find tumors. They are also used to study a cancer’s stage (the extent of its spread) and to decide if treatment is working. Nuclear scans may not find very small tumors, and cannot always tell the difference between benign (not cancer) and malignant (cancer) tumors. They are often used along with other imaging tests to give a more complete picture of what is going on. For example, bone scans that show “hot spots” on the skeleton are usually followed by x-rays of the affected bones, which are better at showing details of the bone structure. Nuclear scans have different names, depending on the organ involved. Some of the more commonly used nuclear scans are: • Bone scans • Gallium scans • Thyroid scans • MUGA scans As a tool for evaluating and managing the care of patients, nuclear imaging studies help physicians: • determine the extent or severity of the disease, including whether it has spread elsewhere in the body • select the most effective therapy based on the unique biologic characteristics of the patient and the molecular properties of a tumor or other disease • determine a patient’s response to specific drugs • accurately assess the effectiveness of a treatment regimen • adapt treatment plans quickly in response to changes in cellular activity • assess disease progression • identify recurrence of disease and help manage ongoing care Nuclear Cardiology Nuclear cardiology studies use noninvasive techniques to assess myocardial blood flow, evaluate the pumping function of the heart as well as visualize the size and location of a heart attack. Among the techniques of nuclear cardiology, myocardial perfusion imaging is the most widely used. Myocardial Perfusion Imaging Myocardial perfusion images are combined with exercise to assess the blood flow to the heart muscle. Exercise is most often in the form of walking on the treadmill. A "chemical" of "pharmacological" stress test using the drug dipyridamole, adenosine or dobutamine is performed in patients who are not able to exercise maximally, providing similar information about the heart's blood flow. A small amount of an imaging agent sestamibi (Cardiolite) or Thallium (Persantine), is injected into the blood stream during rest and during exercise or chemical stress. A scanning device (gamma camera) is used to measure the uptake by the heart of the imaging material during stress) and at rest. If there is significant blockage of a coronary artery, the heart muscle may not get enough of a blood supply in the setting of exercise or during chemical stress. This decrease in blood flow will be detected by the images. Myocardial perfusion studies can thus identify areas of the heart muscle that have an inadequate blood supply as well as the areas of heart muscle that are scarred from a heart attack. In addition to the localization of the coronary artery with atherosclerosis, myocardial perfusion studies quantify the extent of the heart muscle with a limited blood flow and can also provide information about the pumping function of the heart. Thus, it is superior to routine exercise stress testing and provides the necessary information to help identify which patients are at an increased risk and may be candidates for invasive procedures such as coronary angiography, angioplasty or heart surgery. Our Nuclear Medicine Department will contact you prior to your appointment to discuss any prep necessary for you procedure. For further information you may contact the department directly at 239.938.3565. For information on how to prepare for this exam, click here.