Nuclear Medicine A. DEFINITION OF NUCLEAR MEDICINE 1. Involves the use of radiopharmaceuticals used as tracers that emits radiation and can be identified when placed in the human body. By detecting the tracers, information regarding the structure, function, secretion, excretion and volume of a particular organ can be obtained. 2. The images are developed based on the detection of energy emitted from a radioactive substance given to the patient, either intravenously or by mouth. a. Generally, radiation to the patient is similar to that resulting from standard x-ray examinations. B. COMMON USES OF THE PROCEDURE 1. Nuclear medicine images can assist the physician in diagnosing diseases. Tumors, infection and other disorders can be detected by evaluating organ function. Specifically, nuclear medicine can be used to: Analyze kidney function - Also used following a transplant to evaluate blood flow to the kidney and also the kidney’s ability to drain urine Image blood flow and function of the heart Scan lungs for respiratory and blood-flow problems Identify blockage of the gallbladder Evaluate bones for fracture, infection, arthritis or tumor Determine the presence or spread of cancer Identify bleeding into the bowel Locate the presence of infection Measure thyroid function to detect an overactive or underactive thyroid To observe the rate and amount of gastric emptying (use sulfur colloid eggs) C. HOW DOES THE PROCEDURE WORK 1. You are given a small dose of radioactive material, usually intravenously but sometimes orally, that localizes in specific body organ systems. 2. This compound, called a radiopharmaceutical agent or tracer, eventually collects in the organ and gives off energy as gamma rays. 3. The gamma camera detects the rays and works with a computer to produce images and measurements of organs and tissues. 4. The tracer is excreted from the body by way of the bowel (binds with bile) except for the tracer which is given for a bone scan. It is of a phosphate derivative and it is excreted by the kidneys. D. NUCLEAR MEDICINE EQUIPMENT 1. Scanning table for the patient to lie on. 2. Specialized nuclear imaging camera - It is enclosed in metallic housing designed to facilitate imaging of specific parts of the body. It can look like a large round metallic apparatus suspended from a tall, moveable post or a sleek one-piece metal arm that hangs over the examination table. a. The camera can also be located within a large, doughnut- shaped structure similar in appearance to a computed tomography (CT) scanner. b. The camera may be located beneath the table out of view. 3. Computer console processes the data from the procedure. This is usually located in another room. E. HOW IS THE PROCEDURE PERFORMED 1. A radiopharmaceutical agent is usually administered into a vein. a. Depending on which type of scan is being performed, the imaging will be done either immediately, a few hours later, or even several days after the injection. b. Imaging time varies, generally ranging from 20 to 45 minutes. 2. The radiopharmaceutical that is used is determined by what part of the body is under study, since some compounds collect in specific organs better than others. 3. The patient must remain still as possible while the images are being obtained. This is extremely important when a series of images is obtained to show how an organ functions over time. 4. Following the procedure, the quality of the images are checked to ensure that an optimal diagnostic study has been performed. F. WHAT ARE THE BENEFITS VS. RISKS 1. Benefits a. The functional information provided by nuclear medicine examinations is unique and currently unattainable by using other imaging procedures. For many diseases, nuclear medicine studies yield the most useful information needed to make a diagnosis and to determine appropriate treatment, if any. b. Nuclear medicine is much less traumatic than exploratory surgery, and allergic reaction to the radiopharmaceutical material is extremely rare. 2. Risks a. Because the doses of radiopharmaceutical administered are very small, nuclear medicine procedures result in exposure to a small dose of radiation. Nuclear medicine has been used for more than five decades, and there are no known long-term adverse effects from such low-dose studies. b. As with all radiologic procedures, be sure to inform your physician if you are pregnant. In general, exposure to radiation during pregnancy should be kept to a minimum. c. Allergic reactions to the radiopharmaceutical can occur, but are extremely rare. d. Some minor discomfort during a nuclear medicine procedure may arise from the intravenous injection. With some special studies, a catheter may be placed into the bladder, which may cause temporary discomfort. Lying still on the examining table may be uncomfortable for some patients. G. RESPONSIBILITES OF THE NUCLEAR MEDICINE TECHNICIAN 1. Prepares and administers radiopharmaceuticals to patients by IV, IM, SQ, PO under the guidance of a qualified physician. Most of the doses are now dispensed as unit doses. The technician may still need to prepare doses based upon need within the department. 2. Manage the quality control of the substance and understand the half life of each radiopharmaceutical used. 3. Understand and use the protection devices that measure the quantity and distribution of radionuclides deposited in a patient or a patient’s specimen. 4. Evaluate images and data for technical quality.