Illness due to overexposure to harmful electromagnetic waves, usually x-rays or gamma rays. Mild acute illness is manifested by anorexia, headache, nausea, vomiting, and diarrhea. Delayed effects resulting from repeated or prolonged exposure may result in skin ulcers, alopecia, proctitis, enteritis, amenorrhea, sterility, disturbances in blood cell formation, cataract formation, premature aging, and cancer.