Nuclear Medicine
Exposure to nuclear radiation is often harmful to the human body. However, scientists have also found nuclear radiation to be a powerful tool in the field of medicine.
Because radioisotopes are detectable by their radiation, they can be used as tracers that map out specific locations in the body. For example, the radioisotope iodine-131 is absorbed by the thyroid gland in the throat in the same way that iodine-127 is. If iodine-131 is injected into the body, the radiation it emits will show how well the thyroid gland is functioning.
Radioactive tracers can also be used to pinpoint the location of cancer cells. Cancer cells multiply rapidly and absorb glucose much faster than normal cells. If the glucose molecules are “tagged” with a radioactive tracer, such as flourine-18, the location of the cancer cells can be found by tracking areas of high glucose concentration.
Radioisotopes with short half-lives are chosen for medical uses. These isotopes decay so rapidly that after only a day or two, practically none of the isotope remains.