Glossary Term:


radiation therapy


<b>ray</b>-dee-<b>A</b>-shun <b>ther</b>-uh-pee


treatment with high-energy rays (ionizing energy, such as x-rays) to kill cancer cells and shrink tumors. The radiation may come from outside the body (external radiation) or from radioactive materials placed in the tumor (brachytherapy or internal radiation). Radiation therapy may be used to shrink the cancer before surgery, to kill any remaining cancer cells after surgery, or as the main treatment. It may also be used as palliative (non-curative) treatment for advanced cancer. See also brachytherapy, external beam radiation therapy, intensity modulated radiation therapy, palliative treatment, radiation dose, three-dimensional conformal radiation therapy, x-ray.