![](https://webarchive.library.unt.edu/eot2008/20090514030408im_/http://www.cancer.gov/images/spacer.gif) |
|
(ih-RAY-dee-AY-shun)
![](https://webarchive.library.unt.edu/eot2008/20090514030408im_/http://www.cancer.gov/images/spacer.gif)
| The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic irradiation uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called radiation therapy and radiotherapy. |
Previous Definitions: | iris, irofulven, iron, iron overload, irradiated | Next Definitions: | irreversible toxicity, irritable bowel syndrome, irritable colon, ischemia, iseganan hydrochloride |
|
![](https://webarchive.library.unt.edu/eot2008/20090514030408im_/http://www.cancer.gov/images/spacer.gif) |