title: On using 3D γ-analysis for IMRT and VMAT pretreatment plan QA.
abstract: OBJECTIVE
  To investigate using 3D γ analysis for IMRT and VMAT QA.
  
  
  METHODS
  We explored and studied 3D γ-analysis by comparing TPS computed and EPID back-projection reconstructed doses in patient's CT images. Two 3D γ quantities, γ(PTV) and γ(10), were proposed and studied for evaluating the QA results, and compared to 2D γ (MapCheck composite: γ(MC)).
  
  
  RESULTS
  It was found that when 3%(global)/3 mm criteria was used, all IMRT and 90% of VMAT plans passed QA with a γ pass rate ≥90%. A significant statistical correlation was observed between 3D and 2D γ-analysis results for IMRT QA if γ(10) and γ(MC) are concerned, but no significant relation is found between γ(PTV) and γ(MC).
  
  
  CONCLUSIONS
  3D γ analysis based on EPID dose back-projection may provide a feasible tool for IMRT and VMAT pretreatment plan QA.
authors: Radiation Oncology Centers (ROC), Radiological Associates of Sacramento (RAS), Sacramento, CA 95815, USA. wuc@radiological.com
authors: Chuan
authors: C
authors: Wu
authors: Kelly E
authors: KE
authors: Hosier
authors: Kristen E
authors: KE
authors: Beck
authors: Marlyn B
authors: MB
authors: Radevic
authors: Joerg
authors: J
authors: Lehmann
authors: Hao H
authors: HH
authors: Zhang
authors: Aaron
authors: A
authors: Kroner
authors: Sharon C
authors: SC
authors: Dutton
authors: Seth A
authors: SA
authors: Rosenthal
authors: Jonathan K
authors: JK
authors: Bareng
authors: Mark D
authors: MD
authors: Logsdon
authors: David R
authors: DR
authors: Asche
mesh_terms: D005720:Gamma Rays; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D011786:Quality Control; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods* / Q000592:standards; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods* / Q000592:standards; D012984:Software