title: [Evaluation of a Post-analysis Method for Cumulative Dose Distribution in Stereotactic Body Radiotherapy].
abstract: OBJECTIVE
  The purpose of this study was to evaluate a post-analysis method for cumulative dose distribution in stereotactic body radiotherapy (SBRT) using volumetric modulated arc therapy (VMAT) .
  
  
  METHODS
  VMAT is capable of acquiring respiratory signals derived from projection images and machine parameters based on machine logs during VMAT delivery. Dose distributions were reconstructed from the respiratory signals and machine parameters in the condition where respiratory signals were without division, divided into 4 and 10 phases. The dose distribution of each respiratory phase was calculated on the planned four-dimensional CT (4DCT). Summation of the dose distributions was carried out using deformable image registration (DIR), and cumulative dose distributions were compared with those of the corresponding plans.
  
  
  CONCLUSIONS
  Without division, dose differences between cumulative distribution and plan were not significant. In the condition where respiratory signals were divided, dose differences were observed over dose in cranial region and under dose in caudal region of planning target volume (PTV). Differences between 4 and 10 phases were not significant.
  
  
  CONCLUSIONS
  The present method was feasible for evaluating cumulative dose distribution in VMAT-SBRT using 4DCT and DIR.
authors.affiliation: Department of Radiology, University of Tokyo Hospital.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Imae
authors.forename: Naoya
authors.initials: N
authors.lastname: Saotome
authors.forename: Shigeharu
authors.initials: S
authors.lastname: Takenaka
authors.forename: Yuuichi
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: Keiichi
authors.initials: K
authors.lastname: Yano
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakano
authors.forename: Akihiro
authors.initials: A
authors.lastname: Haga
authors.forename: Wataru
authors.initials: W
authors.lastname: Takahashi
authors.forename: Hideomi
authors.initials: H
authors.lastname: Yamashita
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
mesh_terms: D006801:Humans; D019047:Phantoms, Imaging; D011874:Radiometry / Q000379:methods*; D016634:Radiosurgery / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated