The use of high-energy rays or particles to treat disease is called radiation therapy.

Sometimes it is called radiotherapy, x-ray therapy, cobalt therapy, electron beam therapy, or irradiation.

When radiation is used at high levels (many times those used for x-ray exams) this energy can be used to treat cancer and other illnesses. Special equipment is used to aim the radiation at tumors or areas of the body where there is disease. High levels of radiation can kill cells or keep them from growing...