title: Consistency and reproducibility of the VMAT plan delivery using three independent validation methods.
abstract: The complexity of VMAT delivery requires new methods and potentially new tools for the commissioning of these systems. It appears that great consideration is needed for quality assurance (QA) of these treatments since there are limited devices that are dedicated to the QA of rotational delivery. In this present study, we have evaluated the consistency and reproducibility of one prostate and one lung VMAT plans for 31 consecutive days using three different approaches: 1) MLC DynaLog files, 2) in vivo measurements using the multiwire ionization chamber DAVID, and 3) using PTWseven29 2D ARRAY with the OCTAVIUS phantom at our Varian Clinac linear accelerator. Overall, the three methods of testing the reproducibility and consistency of the VMAT delivery were in agreement with each other. All methods showed minimal daily deviations that contributed to clinically insignificant dose variations from day to day. Based on our results, we conclude that the VMAT delivery using a Varian 2100CD linear accelerator equipped with 120 MLC is highly reproducible.
authors.affiliation: Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, TX, USA. Stathakis@uthscsa.edu
authors.forename: Varatharaj
authors.initials: V
authors.lastname: Chandraraj
authors.forename: Sotirios
authors.initials: S
authors.lastname: Stathakis
authors.forename: Ravikumar
authors.initials: R
authors.lastname: Manickam
authors.forename: Carlos
authors.initials: C
authors.lastname: Esquivel
authors.forename: Sanjay S
authors.initials: SS
authors.lastname: Supe
authors.forename: Nikos
authors.initials: N
authors.lastname: Papanikolaou
mesh_terms: D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy*; D008297:Male; D019047:Phantoms, Imaging; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011786:Quality Control; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors