title: A preliminary study of in-house Monte Carlo simulations: an integrated Monte Carlo verification system.
abstract: OBJECTIVE
  To develop an infrastructure for the integrated Monte Carlo verification system (MCVS) to verify the accuracy of conventional dose calculations, which often fail to accurately predict dose distributions, mainly due to inhomogeneities in the patient's anatomy, for example, in lung and bone.
  
  
  METHODS
  The MCVS consists of the graphical user interface (GUI) based on a computational environment for radiotherapy research (CERR) with MATLAB language. The MCVS GUI acts as an interface between the MCVS and a commercial treatment planning system to import the treatment plan, create MC input files, and analyze MC output dose files. The MCVS consists of the EGSnrc MC codes, which include EGSnrc/BEAMnrc to simulate the treatment head and EGSnrc/DOSXYZnrc to calculate the dose distributions in the patient/phantom. In order to improve computation time without approximations, an in-house cluster system was constructed.
  
  
  RESULTS
  The phase-space data of a 6-MV photon beam from a Varian Clinac unit was developed and used to establish several benchmarks under homogeneous conditions. The MC results agreed with the ionization chamber measurements to within 1%. The MCVS GUI could import and display the radiotherapy treatment plan created by the MC method and various treatment planning systems, such as RTOG and DICOM-RT formats. Dose distributions could be analyzed by using dose profiles and dose volume histograms and compared on the same platform. With the cluster system, calculation time was improved in line with the increase in the number of central processing units (CPUs) at a computation efficiency of more than 98%.
  
  
  CONCLUSIONS
  Development of the MCVS was successful for performing MC simulations and analyzing dose distributions.
authors.affiliation: Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Mukumoto
authors.forename: Katsutomo
authors.initials: K
authors.lastname: Tsujii
authors.forename: Susumu
authors.initials: S
authors.lastname: Saito
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Yasunaga
authors.forename: Hideki
authors.initials: H
authors.lastname: Takegawa
authors.forename: Tokihiro
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Hodaka
authors.initials: H
authors.lastname: Numasaki
authors.forename: Teruki
authors.initials: T
authors.lastname: Teshima
mesh_terms: D000465:Algorithms; D019985:Benchmarking; D003196:Computer Graphics; D003198:Computer Simulation; D006801:Humans; D009010:Monte Carlo Method; D010315:Particle Accelerators / Q000295:instrumentation; D019047:Phantoms, Imaging; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods; D014584:User-Computer Interface