 |
|
Approximately 100 radioisotopes are used in medical diagnosis, sterilization of medical products, radiotherapy, and research in nuclear medicine.
- Radioisotopes used in diagnosis are chosen because of their low levels of radioactivity. The minimal radiation used provides valuable medical information but does not cause much harm,
if any, to the patient. Therefore, most radioisotopes that are used for medical diagnosis do not pose a high security risk.
- Radiotherapy is used to destroy cancerous cells, clean blood for transfusion, and for other therapeutic applications. The radioactive materials used in radiotherapy have high radioactivity levels and are used in many places around the world. Thus, these materials may be attractive to terrorists and can be dangerous if inappropriately used.
|
Cancer therapy using a cobalt therapy
unit |
- Brachytherapy is radiotherapy that involves radiation used internally to the body, often for the treatment of cancer. Although externally used radiation sources usually have greater radioactivity, brachytherapy units are more common and more mobile. This easier access and mobility may make brachytherapy units an attractive target for terrorist use.
Industrial applications of radioisotopes include use in instrumentation and measuring devices (both fixed and portable), smoke detectors, sterilization of food and materials through irradiation, non-destructive testing, and gamma radiography.
|
Radiation is commonly used to sterilize
produce. |
- Industrial irradiators are used to sterilize food and medical equipment. They can also be used for other purposes, such as enhancing the color of gemstones. Irradiators usually emit highly penetrating gamma rays. Some irradiators may also use easily dispersible radioactive materials, such as the powdered form of cesium chloride. These factors—the level of radioactivity, the widespread use, and the dispersible form—increase the security threat posed by the irradiators.
- Gamma radiography can be used to check for flaws in pipeline welds. It can also test the structure of metals and other products without altering or destroying the object itself. A lower level of radiation is used in gamma radiography than that in irradiators. However, the portability of the gamma radiography equipment makes these devices a high security risk.
- Scientific applications include use in both biomedical and materials research. Materials research employs such techniques as radiocarbon dating, for which natural carbon-14 is commonly used. In agriculture, radioisotopes are useful for investigating chemical and biological processes in plants and sterilizing pests, such as tsetse flies.
- Radioactive sources can also be used as long-lived power sources for equipment that is too remote or inaccessible for replacement. For example, within the former Soviet Union, highly radioactive radioisotope thermoelectric generators (RTGs) were commonly used for remote power applications, such as naval navigational systems and other military facilities. Hundreds of these units remain along Russia’s northern coastline. These RTGs are generally difficult to reach, but inadequately protected. Because terrorists may be able to get hold of the RTGs, these pose a security risk. Illustrating the security risks, in November 2003, there were press reports that some RTG-powered Russian lighthouses had been vandalized.
|
Abandoned RTGs in the former Soviet Union |
- In addition, radioisotopes have many other applications, ranging from lighting airport runways and emergency exit signs, to determining the moisture content of soil and other materials, to gauging the quantity and density of material between a radioactive source and the radiation detector.
|
|
|