title: Efficacy of stereotactic radiotherapy for brain metastases using dynamic jaws technology in the helical tomotherapy system.
abstract: OBJECTIVE
  Dynamic jaws (DJ) are expected to be useful in stereotactic radiotherapy (SRT) for brain metastases (BM). The efficacy and optimal dose fractionation were investigated.
  
  
  METHODS
  In a planning study, 63 treatment plans were generated for the following 3 conditions: 1.0-cm fixed jaws (FJ), 2.5-cm FJ and 2.5-cm DJ. In a clinical study, 30 Gy/3 fr, 35 Gy/5 fr or 37.5 Gy/5 fr were prescribed depending on tumour size. Clinical results of groups treated with 2.5-cm DJ plans and 1.0-cm FJ were compared.
  
  
  RESULTS
  In the planning study, the treatment times in 2.5-cm DJ and FJ plans were less than that in 1.0-cm FJ plans (p < 0.001). The brain doses in 1.0-cm FJ plans and 2.5-cm DJ plans were smaller than those in 2.5-cm FJ plans (p < 0.05). In the clinical study, 34 patients with 68 BM were treated with SRT. Of those, 15 patients with 34 BM were treated with 2.5-cm DJ plans and 19 patients with 34 BM were treated with 1.0-cm FJ plans. The overall survival and local tumour control (LC) rates were 52 and 93% at 12 months, respectively. The DJ system achieved favourable LC and 29% shorter treatment time compared with the FJ system (p < 0.001). Grade 2 or 3 necrosis occurred more frequently in patients with 15 cc or larger tumour volumes (p = 0.05).
  
  
  CONCLUSIONS
  DJ technology enables treatment time to be reduced without worsening the dose distribution and clinical efficacy. The prescribed doses in this study may be acceptable for patients with small tumour volumes.
  
  
  CONCLUSIONS
  DJ technology enables treatment time to be reduced without worsening the dose.
authors.affiliation: 1 Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Murai
authors.affiliation: 2 Department of Radiology, Okazaki City Hospital, Okazaki, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hayashi
authors.affiliation: 1 Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Manabe
authors.affiliation: 1 Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Chikao
authors.initials: C
authors.lastname: Sugie
authors.affiliation: 1 Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Taiki
authors.initials: T
authors.lastname: Takaoka
authors.affiliation: 1 Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yanagi
authors.affiliation: 3 Department of Respiratory Medicine, Allergy and Clinical Immunology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Oguri
authors.affiliation: 1 Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Matsuo
authors.affiliation: 4 Department of Radiology and Radiation Oncology, Aichi Medical University, Nagakute, Japan.
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Mori
authors.affiliation: 1 Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shibamoto
mesh_terms: D001932:Brain Neoplasms / Q000532:radiotherapy* / Q000556:secondary*; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D015996:Survival Rate