@article{oai:repo.qst.go.jp:00049402,
 author = {Ikawa, Hiroaki and Koto, Masashi and K. Ebner, Daniel and Hayashi, Kazuhiko and Takagi, Ryo and Tonogi, Morio and Nomura, Takeshi and Tsuji, Hiroshi and Kamada, Tadashi and Ikawa, Hiroaki and Koto, Masashi and Hayashi, Kazuhiko and Takagi, Ryo and Tonogi, Morio and Tsuji, Hiroshi and Kamada, Tadashi},
 issue = {1},
 journal = {Advances in Radiation Oncology},
 month = {Jan},
 note = {Introduction
We previously demonstrated the efficacy and utility of carbon-ion radiation therapy (CIRT), finding acceptable toxicity with preserved speech and wallowing function in the setting of locally advanced tongue carcinoma. The 5-year local control rate and overall survival rate were 92.0% and 72%, respectively, among 18 patients with locally advanced adenoid cystic carcinoma of the tongue base. However, osteoradionecrosis (ORN) of the mandibular bone remains a serious adverse event for patients receiving CIRT. The incidence of grade 3 mandibular ORN was 11.1%. Further study found that the volume of maxilla receiving more than 50 Gy (relative biological effectiveness [RBE]) across 16 fractions (maxilla V50 Gy [RBE] [mL]) and the presence of teeth within the planning target volume (PTV) were significant independent risk factors for ORN. As such, reducing the
volume irradiated with high dose is one key way to reduce the risk of mandibular ORN. 
  Spacers are widely used to prevent ORN in brachytherapy for tongue ncer.  However, with regard to external photon radiation therapy (RT) for tongue arcinoma,there have been no reports on the utility of spacers focused on revention of ORN, perhaps because of the dose distribution inherent to photon RT. CIRT offers improved lateral dose distribution with minimal target exit
dose and thereby may benefit from the employment of a spacer-including mouthpiece.
  In this technical report, we introduce and evaluate the utility of a spacer-including mouthpiece with the aim of producing reduced mandible V50 for the treatment of tongue carcinoma.},
 pages = {15--19},
 title = {The Efficacy of a Custom-Made Mouthpiece With Spacer to Reduce Osteoradionecrosis in Carbon-Ion Radiation Therapy for Tongue-Base Tumor},
 volume = {4},
 year = {2019}
}