title: Comparison of mean radiation dose and dosimetric distribution to tooth-bearing regions of the mandible associated with proton beam radiation therapy and intensity-modulated radiation therapy for ipsilateral head and neck tumor.
abstract: OBJECTIVE
  The purpose of this study was to compare the dosimetric distribution of ipsilateral proton beam radiation therapy (PBRT) with intensity-modulated radiation therapy (IMRT) in the tooth-bearing region of the mandible in patients with head and neck cancer (HNC).
  
  
  METHODS
  The mandibular dosimetric distribution in patients with head and neck cancer treated with ≥60 Gy relative biologic equivalent PBRT was evaluated. The mean radiation doses were calculated in 5 regions: ipsilateral molar, ipsilateral premolar, anterior, contralateral premolar, and contralateral molar (CM) regions. CM was used as the reference region for comparative analysis. The mandibular dosimetric distribution in patients treated with PBRT was compared with that in IMRT patients with similar tumor sites and planning target volumes.
  
  
  RESULTS
  The mean radiation dose to the contralateral regions was lower in patients treated with PBRT compared with those treated with IMRT. The average mean radiation doses to the reference region (CM) in patients treated with PBRT (relative biologic equivalent) versus IMRT were oropharynx (2.2 Gy vs 23.2 Gy; P < .00002), parotid (0 Gy vs 11.8 Gy; P = .01), and oral cavity (0.4 Gy vs 15.6 Gy; P = .006).
  
  
  CONCLUSIONS
  This study revealed the effective tissue-sparing capability of PBRT compared with IMRT. Utilization of PBRT could translate to less radiation-related toxicity.
authors.affiliation: Oral/Dental Oncology Research Fellow, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, USA.
authors.forename: Adepitan A
authors.initials: AA
authors.lastname: Owosho
authors.affiliation: Assistant Attending, Dental Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, USA.
authors.forename: SaeHee K
authors.initials: SK
authors.lastname: Yom
authors.affiliation: Medical Dosimetrist, ProCure Proton Therapy Center, Somerset, NJ, USA.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Han
authors.affiliation: Medical Dosimetrist, ProCure Proton Therapy Center, Somerset, NJ, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Sine
authors.affiliation: Attending, Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, USA.
authors.forename: Nancy Y
authors.initials: NY
authors.lastname: Lee
authors.affiliation: Chief, Dental Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, USA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Huryn
authors.affiliation: Attending, Dental Service, Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, USA. Electronic address: Estiloc@mskcc.org.
authors.forename: Cherry L
authors.initials: CL
authors.lastname: Estilo
mesh_terms: D003952:Diagnostic Imaging; D005260:Female; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000528:radiation effects*; D011832:Radiation Injuries / Q000000981:diagnostic imaging / Q000209:etiology*; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated; D047368:Tumor Burden