Dictionary of Cancer Terms
View in Spanish: Radiación
Radiation (RAY-dee-AY-shun)
Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).
Source: National Cancer Institute Dictionary of Cancer Terms, available at www.cancer.gov/dictionary.