Ototoxic effects of irradiation.

In this study ototoxic effect of ionizing radiation was studied in 70 ears with minimum follow up of 6 months post radiotherapy. Patients of nasopharyngeal carcinoma and with conductive deafness pre radiotherapy were excluded from the study to eliminate mechanical obstruction that may play role in Eustachian tube dysfunction. We found that Eustachian tube dysfunction and conductive deafness were reversible where as Sensorineural hearing loss was an irreversible effect of radiotherapy. Dose of radiation was directly proportional to ototoxicity, minimum 60 Gys of total radiation dose was required to produce significant ototoxicity.