Use of a novel tongue-sparing intraoral prosthesis for radiation therapy in a head and neck patient: A case report.

We designed an indigenous novel tongue-sparing intraoral prosthesis (TS-IOP) to minimize tongue toxicity in a 58-year-old patient with submental soft tissue sarcoma. We initially performed radiotherapy planning computed tomography (CT) using an intraoral prosthesis (IOP) to reduce the dose to the hard palate. However, IOP-induced tongue compression increased the oral tongue dose during radiotherapy planning. Therefore, we developed a TS-IOP that separated the hard palate from the floor of the mouth without compressing the tongue, thereby minimizing radiation exposure to the oral tongue. Upper and lower jaw dental impressions were obtained on a single wax sheet, and customized wax bolus sheets were prepared according to the dental impressions and mouth opening. The bolus was made U-shaped and hollow at the center to prevent tongue compression. Radiotherapy planning CT was subsequently performed using the TS-IOP and a head-and-neck thermoplastic mask. The TS-IOP achieved a lower radiation dose to the oral tongue while maintaining adequate target coverage. This novel prosthesis may be useful for lesions involving the floor of the mouth or submental region by keeping the oral tongue outside the high-dose region. Further clinical validation in larger cohorts is warranted.