title: [Positional accuracy and quality assurance of Backup JAWs required for volumetric modulated arc therapy].
abstract: The tolerance of the Backup diaphragm (Backup JAW) setting in Elekta linac was specified as 2 mm according to the AAPM TG-142 report. However, the tolerance and the quality assurance procedure for volumetric modulated arc therapy (VMAT) was not provided. This paper describes positional accuracy and quality assurance procedure of the Backup JAWs required for VMAT. It was found that a gap-width error of the Backup JAW by a sliding window test needed to be less than 1.5 mm for prostate VMAT delivery. It was also confirmed that the gap-widths had been maintained with an error of 0.2 mm during the past one year.
authors.affiliation: Department of Radiology, Osaka City University Hospital.
authors.forename: Daisaku
authors.initials: D
authors.lastname: Tatsumi
authors.forename: Ryosei
authors.initials: R
authors.lastname: Nakada
authors.forename: Akinori
authors.initials: A
authors.lastname: Ienaga
authors.forename: Akane
authors.initials: A
authors.lastname: Yomoda
authors.forename: Makoto
authors.initials: M
authors.lastname: Inoue
authors.forename: Takao
authors.initials: T
authors.lastname: Ichida
authors.forename: Masako
authors.initials: M
authors.lastname: Hosono
mesh_terms: D006801:Humans; D008297:Male; D010315:Particle Accelerators; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011786:Quality Control; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation* / Q000379:methods*; D061106:Radiotherapy Setup Errors / Q000517:prevention & control*; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation* / Q000379:methods*