Cancer Facts Therapy Radiotherapy, also called radiation
therapy, is the treatment of cancer and other diseases with
ionizing radiation. Ionizing radiation deposits energy that
injures or destroys cells in the area being treated (the "target
tissue") by damaging their genetic material, making it
impossible for these cells to continue to grow. Although
radiation damages both cancer cells and normal cells, the latter
are able to repair themselves and function properly.
Radiotherapy may be used to treat localized solid tumors, such
as cancers of the skin, tongue, larynx, brain, breast, or
uterine cervix. It can also be used to treat leukemia and
lymphoma (cancers of the blood-forming cells and lymphatic
system, respectively). One type of radiation therapy commonly
used involves photons, "packets" of energy. X-rays were the
first form of photon radiation to be used to treat cancer.
Depending on the amount of energy they possess, the rays can be
used to destroy cancer cells on the surface of or deeper in the
body.