Delayed effects of ionizing radiation on the ear.
The question of damage to the ear from exposure to ionizing radiation was addressed by exposing groups of chinchillas to fractioned doses of radiation (2 Gy per day) for total doses ranging from 40 to 90 Gy. In order to allow any delayed effects of radiation to become manifest, the animals were sacrificed two years after completion of treatment and their temporal bones were prepared for microscopic examination. The most pronounced effect of treatment was degeneration of sensory and supporting cells and loss of eighth nerve fibers in the organ of Corti. Damage increased with increasing dose of radiation. The degree of damage found in many of these ears was of sufficient magnitude to produce a permanent sensorineural hearing loss.
D000818:Animals; D001300:Audiometry, Evoked Response; D002682:Chinchilla; D004307:Dose-Response Relationship, Radiation; D007758:Ear, Inner / Q000473:pathology / Q000528:radiation effects*; D004432:Ear, Middle / Q000473:pathology / Q000528:radiation effects*; D006198:Hair Cells, Auditory / Q000528:radiation effects; D006319:Hearing Loss, Sensorineural / Q000473:pathology; D009410:Nerve Degeneration / Q000528:radiation effects; D009413:Nerve Fibers, Myelinated / Q000528:radiation effects; D010025:Osteoradionecrosis / Q000473:pathology; D011833:Radiation Injuries, Experimental / Q000473:pathology*; D013701:Temporal Bone / Q000528:radiation effects; D000159:Vestibulocochlear Nerve / Q000528:radiation effects