Radiation therapy involves the use of high-energy radiation to kill cancer cells and eliminate or shrink tumors. Radiation therapy may be used as the main treatment for certain types of cancer or may performed either prior to or following surgery to remove the tumor.
The source of the radiation may come from either:
External radiation therapy, in which a machine outside the body (external radiation therapy) generates x-rays or gamma rays to which the patient is exposed
Implant radiation therapy, in which radiation-producing materials (radioisotopes) contained in thin plastic tubes are surgically placed into the area where the cancer cells are found