The Reporter's Handbook on Nuclear Materials, Energy & Waste Management

Civilian Uses of Radiation andRadioactive Material (Other thanCommercial Nuclear Power)

120 | Civilian Uses of Radiation and Radioactive Material (Other than Commercial Nuclear Power) Written by Bernadette M. West, based in part on an interview with P. Andrew Karam, with comments by David C. Kocher Background We often fail to recognize the many beneficial civilian uses of nuclear materials other than commercial nuclear power. These include use of nuclear materials used in the field of medicine and in food preparation and a variety of industrial applications. The U.S. Nuclear Regulatory Commission (NRC) is the agency that has authority over civilian uses of nuclear materials in the United States. Identifying the Issues Diagnostic Nuclear Medicine In the field of nuclear medicine health professionals conduct diagnostic tests that create images of the body that can be used to identify and stage certain diseases, such as cancer. These tests detect gamma rays emitted from a radioactive substance given to the patient either orally or intravenously to create an image of what is happening in the body. The type of radioactive tracer used depends on the target organ. The tracer accumulates in the organ and gives off energy as gamma rays that a special crystal within a gamma camera is able to detect. Patients lie on a scanning table and a specialized nuclear imaging camera is used. Pictures and measurements of the organ and surrounding tissue are taken. These images can be used to help diagnose tumors, infection, and other disorders. The procedures are usually time consuming and can take several hours to perform. The findings from nuclear medicine are often critical in diagnosing and treating certain diseases. These tests provide information about the functioning Civilian Uses of Radiation and Radioactive Material | 121 of an organ within a specific region of the body that often cannot be obtained from other diagnostic tests, such as x-rays. Nuclear medicine tests can help diagnose many conditions, including cancer, infection, arthritis, bone fractures, and blockages of the gallbladder, and assess blood flow, thyroid and kidney function, and functioning of the heart and lungs. Positron emission tomography (PET) is an example of a nuclear medicine test. A PET scan is a diagnostic test that produces a three-dimensional image or map showing the functioning of parts of the body. In a PET scan, the patient is injected with a radioactive substance that emits positrons, which are positively charged electrons. These positron emitters (the PE in PET) are attached to chemicals or drugs that travel to a specific part of the body, and then a scan is done. When the emitted positrons come into contact with nearby electrons, gamma radiation is produced that can then be detected by the scanner and an image created. On a PET scan, different colors and levels of brightness can be observed. Cancerous tissue will appear brighter than normal tissue on the PET images. The images produced by the PET scan are used to diagnose cancer and to calculate the effects of cancer therapy. They are also used to observe blood flow to the heart and to determine the status of heart tissue following a heart attack. They are also used in studies of the brain involving memory disorders and to look for possible tumors or to explain seizure disorders. The PET scan helps health professionals detect changes in biochemical processes that suggest disease before changes in anatomy are apparent with other imaging tests, such as the CT scan (computed axial tomography) or MRI (magnetic resonance imaging). The radioactivity is very short-lived. Radiation exposure is low and the substance amount is so small that it does not affect normal processes of the body. Nuclear Medicine and the Treatment of Disease In addition to its use in diagnosing disease, radioactive substances are sometimes used in treating disease and for palliative purposes. While many of these treatments involve low doses and minimal risk, it is important to note that some treatments using radioactive substances use higher doses and involve higher levels of risk. Nuclear medicine is used to deliver chemotherapy or other treatments to the exact location where they are needed, then allowing health care providers to monitor how the body is responding to the treatment. Medicines with trace amounts of a radioactive material called radiopharmaceuticals are used in nuclear medicine. For example, iodine-131 is used to treat thyroid cancer and other diseases of the thyroid. In cases of thyroid cancer, radioactive io- 122 | The Reporter’s Handbook: Briefs dine is used...