title: Dosimetric impact of Acuros XB dose calculation algorithm in prostate cancer treatment using RapidArc.
abstract: OBJECTIVE
  The purpose of this study is to assess the dosimetric impact of Acuros XB dose calculation algorithm (AXB), in comparisons with Anisotropic Analytical Algorithm (AAA) calculations in prostate cancer treatment using RapidArc.
  
  
  METHODS
  A computed tomography (CT) dataset of low-risk prostate cancer patients treated at Arizona Center for Cancer Care was selected and contoured for prostate, seminal vesicles, and organs at risk (OARs)(rectum, bladder, and femur heads). Plans were created for 6 MV photon beam using RapidArc technique in Eclipse treatment planning system. Dose calculations were performed with AAA and AXB for same number of monitor units and identical beam setup. Mean and maximum doses to planning target volume (PTV) and OARs were analyzed. Additionally, minimum dose to PTV and V100 was analyzed. Finally, point-dose difference between planar dose distributions of AAA and AXB plans was investigated.
  
  
  RESULTS
  The highest dose difference was up to 0.43% (range: 0.05-0.43%, P> 0.05) for PTV and 1.98% (range: 0.22-1.98%, P> 0.05) for OARs with AAA predicting higher dose than AXB. The V100 values of AAA plans (95 %) and AXB plans (range: 93.1-97.9 %) had an average difference of 0.89 ± 1.47% with no statistical significance (P = 0.25411). The point-dose difference analysis showed that AAA predicted higher dose than AXB at significantly higher percentage (in average 94.15) of total evaluated points.
  
  
  CONCLUSIONS
  The dosimetric results of this study suggest that the AXB can perform the dose computation comparable to AAA in RapidArc prostate cancer treatment plans that are generated by a partial single-arc technique.
authors.affiliation: Department of Radiation Oncology, Arizona Center for Cancer Care, Peoria, Arizona; Department of Medical Physics, ProCure Proton Therapy Center, Oklahoma City, OK, USA.
authors.forename: Suresh
authors.initials: S
authors.lastname: Rana
authors.forename: Kevin
authors.initials: K
authors.lastname: Rogers
authors.forename: Terry
authors.initials: T
authors.lastname: Lee
authors.forename: Daniel
authors.initials: D
authors.lastname: Reed
authors.forename: Christopher
authors.initials: C
authors.lastname: Biggs
mesh_terms: D000465:Algorithms; D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*