title: Monte Carlo modeling of a Novalis Tx Varian 6 MV with HD-120 multileaf collimator.
abstract: A Monte Carlo model of the Novalis Tx linear accelerator equipped with high-definition multileaf collimator (HD-120 HD-MLC) was commissioned using ionization chamber measurements in water. All measurements in water were performed using a liquid filled ionization chamber. Film measurements were made using EDR2 film in solid water. Open rectangular fields defined by the jaws or the HD-MLC were used for comparison against measurements. Furthermore, inter- and intraleaf leakage calculated by the Monte Carlo model was compared against film measurements. The statistical uncertainty of the Monte Carlo calculations was less than 1% for all simulations. Results for all regular field sizes show an excellent agreement with commissioning data (percent depth-dose curves and profiles), well within 1% of difference in the relative dose and 1 mm distance to agreement. The computed leakage through HD-MLCs shows good agreement with film measurements. The Monte Carlo model developed in this study accurately represents the new Novalis Tx Varian linac with HD-MLC and can be used for reliable patient dose calculations.
authors.affiliation: Cancer Therapy and Research Center, Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, TX 78229-4427, USA.
authors.forename: Luis Alberto
authors.initials: LA
authors.lastname: Vazquez-Quino
authors.forename: Brian
authors.initials: B
authors.lastname: Massingill
authors.forename: Chengyu
authors.initials: C
authors.lastname: Shi
authors.forename: Alonso
authors.initials: A
authors.lastname: Gutierrez
authors.forename: Carlos
authors.initials: C
authors.lastname: Esquivel
authors.forename: Tony
authors.initials: T
authors.lastname: Eng
authors.forename: Nikos
authors.initials: N
authors.lastname: Papanikolaou
authors.forename: Sotirios
authors.initials: S
authors.lastname: Stathakis
mesh_terms: D003198:Computer Simulation; D006801:Humans; D008962:Models, Theoretical; D009010:Monte Carlo Method; D010315:Particle Accelerators / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation* / Q000379:methods