 At the end of the first day of radiation therapy, the pharmacy department of the CHU de Québec will prepare the sodium thiosulfate hyaluronate gel by mixing 0.55 ml of a 25 solution of sodium thiosulfate pentahydrate Seacalphyx, Drug identification number DIN 02386666, Seaford Pharmaceuticals Inc. and 0.55 ml of a hyaluronate gel Healon 10 mg, Abbott Medical Optics Inc.. After a local anesthesia of the tympanic membrane, the otologist will deposit 0.1 ml of the gel exactly on the round window of the middle ear. From there the STS should diffuse towards the cochlea. The same procedure will be repeated on the eve of the subsequent Cisplatin treatments on days 22 and 43. 