Radioactive isotopes are any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays. Every chemical element has one or more radioactive isotopes. More than 1,000 radioactive isotopes of the various elements are known.. Approximately 50 of the isotopes are found in nature; the rest are produced artificially as the direct products of nuclear reactions or indirectly as the radioactive descendants of these products. Radioactive emissions are easily detected and can be tracked until they disappear leaving no trace. Radioactive isotopes have many useful applications. Medicine:
Radioisotopes are used for diagnosis, treatment, and research. Over 10,000 hospitals worldwide use radioisotopes in medicine, and about 90% of the procedures are for diagnosis. Radioisotopes give doctors the ability to look inside the body and observe soft tissues and organs, in a manner similar to the way x-rays provide images of bones. Radioisotopes carried in the blood also allow doctors to detect clogged arteries or check the functioning of the circulatory system. Doctors also use radio-pharmaceuticals or radioactive drugs to detect problems within a body organ. The radioisotope used in about 80 percent of nuclear diagnostic procedures is Tc-99m. Tc-99m is used to diagnose osteoporosis, a condition caused by calcium deficiency in older people, especially women. Radioactive chemical tracers emitting gamma rays or positrons can provide diagnostic information about a person's internal anatomy and the functioning of specific organs.
The applications of radioisotopes in industry are numerous. Radioactive isotopes of various kinds are used for measuring the thickness of metal or plastic sheets; their precise thickness is indicated by the strength of the radiations that penetrate the material being inspected....