Radiation is very important in the treatment of diseases. In medicine, radioactive isotopes are used primarily in two ways: diagnosis, the use of the radiation emitted by radioactive isotopes to create visual images of affected organs and glands; and therapy, the use of radiation in fighting cancer cells and other disease-causing cells in the body.
Technetium, the first element to be created artificially, is radioactive. Its isotope technetium-99 is one of the most widely used radioactive nuclide in medicine. Radioactive nuclide is an nuclide with an unstable nucleus that spontaneously emits energy (radiation). It can be used to study the functioning of internal organs, such as the heart, kidneys, liver a d lungs, and in the glands such as the thyroid. For example, a compound of technetium (99TcO4) is used to detect and pinpoint brain tumors.
The radioactive isotope cobalt-60 emits intense gamma rays is used extensively in radiation therapy of cancer cells. Sodium-24 is used in monitoring blood flow, strontium-87 is used to study bone growth, strontium-85 is used to detect bone cancer, and plutonium-238 is used in pacemakers.
Radiation can also be used to diagnose pernicious anemia. Doctors inject the patient with vitamin B-12 containing some cobalt-60. Radiation detectors measure the amount of cobalt-60 and the vitamin in the patient's urine. This information tells doctors if the patient is absorbing the vitamin normally. A radioactive isotope of iodine is used in diagnosing and subsequently treating goiter, a disorder caused by underproduction or overproduction of thyroid hormones.
Radiation is also used in dating materials, tracing and in industry. Using knowledge of the activity of radioisotopes, the age of rocks, fossils and other archaeological findings can be determined. For example, a technique known as radiocarbon dating uses the radioactive isotope carbon-14 to date fossils, such as bones and remains of ancient trees. Other nuclides also used, such as uranium-238 and potassium-40, which are used to date rocks.
The use of radioisotopes in tracking down a substance from one chemical reaction or process to another is known as isotopic tracing. The radioisotope is referred to as the tracer. Traces are used in studying the mechanisms of chemical reactions. For example, a sugar molecule can be "labeled" with carbon-14. Through its radioactivity, the progress of the sugar molecule in the body can be monitored.
Tracers are used in industry to detect small amounts of wear in moving parts, to evaluate the quality of oil used for lubricating machines, and to gauge thickness and weakness of metals and plastics.