title: Radiation-induced Parotid Gland Atrophy in Patients with Head and Neck Cancer After Carbon-ion Radiotherapy.
abstract: This study aimed to clarify the relationship between dosimetric factors and parotid gland (PG) atrophy after carbon ion radiotherapy (C-ion RT).
  
  
  
  Fifty-four patients with head and neck tumours were enrolled and 93 irradiated PGs were analyzed. Thirty and 24 patients were treated with total doses [relative biological effectiveness (RBE)] of 57.6 Gy and 64.0 Gy, respectively, in 16 fractions. PG volumes were measured using computed tomographic images obtained before C-ion RT and every 3-6 months thereafter.
  
  
  
  The median follow-up period was 46.4 months (range=24.0-123.0 months). Univariate analysis showed that PG volumes receiving more than 5, 10, 15, and 20 Gy RBE (V5, V10, V15 and V20, respectively), mean dose, and maximum dose were significantly associated with PG atrophy. Multivariate analysis indicated that only V5 was significantly associated with atrophy.
  
  
  
  Increasing V5 was a significant risk factor for PG atrophy after C-ion RT.
authors: National Institute of Radiological Science Hospital, National Institutes for Quantum and Radiological Sciences and Technology, Chiba, Japan.|Department of Oral and Maxillofacial Surgery, Tokyo Dental College, Chiba, Japan.
authors: Takamichi
authors: T
authors: Morikawa
authors: National Institute of Radiological Science Hospital, National Institutes for Quantum and Radiological Sciences and Technology, Chiba, Japan koto.masashi@qst.go.jp.
authors: Masashi
authors: M
authors: Koto
authors: National Institute of Radiological Science Hospital, National Institutes for Quantum and Radiological Sciences and Technology, Chiba, Japan.
authors: Azusa
authors: A
authors: Hasegawa
authors: National Institute of Radiological Science Hospital, National Institutes for Quantum and Radiological Sciences and Technology, Chiba, Japan.
authors: Ryo
authors: R
authors: Takagi
authors: National Institute of Radiological Science Hospital, National Institutes for Quantum and Radiological Sciences and Technology, Chiba, Japan.
authors: Akira
authors: A
authors: Fujikawa
authors: National Institute of Radiological Science Hospital, National Institutes for Quantum and Radiological Sciences and Technology, Chiba, Japan.
authors: Hiroshi
authors: H
authors: Tsuji
authors: Department of Oral and Maxillofacial Surgery, Tokyo Dental College, Chiba, Japan.
authors: Takahiko
authors: T
authors: Shibahara
authors: National Institute of Radiological Science Hospital, National Institutes for Quantum and Radiological Sciences and Technology, Chiba, Japan.
authors: Tadashi
authors: T
authors: Kamada
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D063193:Heavy Ion Radiotherapy / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010306:Parotid Gland / Q000473:pathology*
keywords: Carbon-ion radiotherapy; dose-volume histogram; parotid gland; radiotherapy; xerostomia