Nuclear Medicine

Nuclear Medicine is a medical specialty in which the diagnosis and treatment of human diseases are made by the use of a small number of radioactive tracers. After administration of the tracer, images of the organ of interest in the patient’s body are obtained with a gamma camera that shows the localization of the tracer in the organ, and physicians interpret them for the diagnosis of disease. Certain diseases are treated with high energy radiotracers in nuclear medicine based on the concept that high dose.

The patient is given intravenously, for some studies orally or by inhalation, a small dosage of a radiotracer specific for an organ under study. Some studies require that the patient exercise or receive a drug that dilates the arteries in the heart. The tracer localizes in the organ and emits gamma radiations that are detected by a special camera to form an image of the organ. Imaging of the organ is performed immediately, hours or days after administration of the tracer, depending on the type of study. The duration of imaging itself ranges from 15 to 120 minutes for different studies. Most tests require the patient to lie down on a bed, while others require the patient to sit. Some tests require taking many short pictures of the organ serially followed by one long picture at the end. Nuclear physicians interpret the images and can see any abnormality in the image either as a ‘hot’ area with increased localization of the tracer or a cold spot with decreased localization of the tracer, depending on the property of the tracer.

The tracer is administered most commonly by injection through the vein, and for some tests orally or by inhalation.

It depends on the type of test. Since the localization of the radiotracer varies with the physiological behavior of the organ and the characteristics of the tracer, the time for optimal localization varies from organ to organ. Sometimes two tests are needed for some disease entities such as with cardiac studies. For example, a lung scan needs only half an hour, a heart study may take 2 – 3 hours, and yet other tests may take 24-48 hours to complete.

Because the administered radioactive dosages contain only a minimal amount of the carrier drug, no significant adverse or allergic reactions from the drug is commonly encountered. A patient receives a certain amount of radiation dose from nuclear medicine studies which is comparable to a diagnostic X-ray.

Nuclear medicine tests are very sensitive and can detect some diseases at early stages. Unlike MRI and CT studies that give only structural information, nuclear medicine tests provide information about the physiological or functional status and viability of different organs and tissues.