irradiation /irā′dē·ā″shən/ [L, irradiare, to beam upon] , exposure to any form of radiant energy, such as heat, light, or x-rays. Radioactive sources of radiant energy, such as x-rays or isotopes of iodine or cobalt, are used diagnostically to examine internal body structures. The same or similar sources of radioactivity in larger amounts are used to destroy microorganisms or tissue cells that have become cancerous. Infrared or ultraviolet light may be used to produce heat in body tissues for pain relief or to treat acne, psoriasis, or other skin ailments. Ultraviolet light is also used to identify certain bacteria and toxic molds. See also radiation sickness, radioactivity, ultraviolet. −irradiate, v.
