Describe the uses of radioactive sources within medicine.

Although our knowledge of radiation is fairly recent (since the 1890s), human beings have developed a large number of uses of radiation sources in medicines. The most common applications are in imaging and treatment. In fact, it has been estimated that 7 out of 10 Americans have had x-rays or radiation therapy.
X-rays: Most of us are familiar with x-rays which are very commonly used for detecting any bone fracture or damage. X-rays can pass through our skin, however, bones being denser than the skin, cast shadows. This allows the medical practitioners to image our bones and teeth, and check for any anomalies. X-ray machines can also be connected to computers to obtain colored images. Such advanced equipment allows the doctors to detect the location and size of tumors and other anomalies in our bodies.
Radiation therapy: The most common application of radiation therapy is in the treatment of cancer. The radiations are capable of weakening and/or destroying the specifically targeted cells. This allows the doctors to treat the patients suffering from the various forms of cancer. An example is the use of Iodine-131 (a radioactive isotope of element iodine) in the treatment of thyroid cancer.
Equipment sterilization: Gamma rays can be used to sterilize medicinal equipment since these rays are capable of destroying and/or inactivating microbes. Typically, the surgical equipment can be sealed in a pouch and the same can be treated by using a radiation source capable of generating the gamma rays. As long as the pouch stays sealed, the equipment remains sterile and hence can be used at a later time by the medical practitioner.
In Medical research: Radiation sources are also used in medicinal research. An example is the testing of pharmaceutical drugs for their effectiveness and safety. Radiation sources are commonly used to determine if the drug will accumulate in non-targeted parts of the body and what effects it will have. Radiation sources are also commonly used in metabolic studies and genetic engineering.