title: Interinstitutional variations in planning for stereotactic body radiation therapy for lung cancer.
abstract: OBJECTIVE
  The aim of this study was to assess interinstitutional variations in planning for stereotactic body radiation therapy (SBRT) for lung cancer before the start of the Japan Clinical Oncology Group (JCOG) 0403 trial.
  
  
  METHODS
  Eleven institutions created virtual plans for four cases of solitary lung cancer. The created plans should satisfy the target definitions and the dose constraints for the JCOG 0403 protocol.
  
  
  RESULTS
  FOCUS/XiO (CMS) was used in six institutions, Eclipse (Varian) in 3, Cadplan (Varian) in one, and Pinnacle3 (Philips/ADAC) in one. Dose calculation algorithms of Clarkson with effective path length correction and superposition were used in FOCUS/XiO; pencil beam convolution with Batho power law correction was used in Eclipse and Cadplan; and collapsed cone convolution superposition was used in Pinnacle3. For the target volumes, the overall coefficient of variation was 16.6%, and the interinstitutional variations were not significant. For maximal dose, minimal dose, D95, and the homogeneity index of the planning target volume, the interinstitutional variations were significant. The dose calculation algorithm was a significant factor in these variations. No violation of the dose constraints for the protocol was observed.
  
  
  CONCLUSIONS
  There can be notable interinstitutional variations in planning for SBRT, including both interobserver variations in the estimate of target volumes as well as dose calculation effects related to the use of different dose calculation algorithms.
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Kyoto University, Kyoto, Japan.
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Kenji
authors.initials: K
authors.lastname: Takayama
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nagata
authors.forename: Etsuo
authors.initials: E
authors.lastname: Kunieda
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Tateoka
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishizuka
authors.forename: Takashi
authors.initials: T
authors.lastname: Mizowaki
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Norihisa
authors.forename: Masato
authors.initials: M
authors.lastname: Sakamoto
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Narita
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishikura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D000704:Analysis of Variance; D002985:Clinical Protocols; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D013238:Stereotaxic Techniques; D014057:Tomography, X-Ray Computed