Irradiation, exposure to radiation such as ultraviolet rays, X rays, and gamma rays, or to beams of atomic particles such as neutrons. The body requires ultraviolet radiation to manufacture vitamin D. Ultraviolet irradiation is used in the food and pharmaceutical industry. Irradiation by X rays is used as a method of destroying cancerous tissue. Irradiation by gamma rays is used to sterilize insects and prevent them from reproducing and continually infesting grain and other foodstuffs. Gamma-ray irradiation may also kill bacteria in food and preserve it for long periods. Irradiation of elements with beams of particles in a nuclear reactor is a method of making radioisotopes.
See also: Radiation.