title: CT-based virtual simulation using the AdvantageSim 4.1. system. Description of reliability and accuracy.
abstract: BACKGROUND
  CT simulation systems provide integration of CT-based planning target volumes, which allows to operate without the conventional simulator. The aim of our study was the quantitative assessment of the accuracy of field alignment and isocenter position using the new virtual simulation system AdvantageSim 4.1. for different treatment regions.
  
  
  METHODS
  Twenty-seven patients with prostate cancer, 23 patients with head and neck cancer and 30 lung cancer patients were included in this prospective trial. CT-based virtual simulation was performed to define treatment isocenter position. The linear discrepancies of the digitally reconstructed beam's eye views were compared with the conventional simulation and first treatment verification images.
  
  
  RESULTS
  Among all patients the mean difference of isocenter position between conventional and virtual simulation was 3.5 mm. The isocenter displacements ranged from 0 to 6 mm. There was no significant difference in isocenter accuracy between the different treatment regions.
  
  
  CONCLUSIONS
  Virtual simulation with AdvantageSim 4.1. is feasible in daily routine and allows to replace conventional simulation for different target volumes with a reliable accuracy of isocenter and field alignment. The beam's eye views allow the precise evaluation of the coverage of the planning target volume and the shielding of organs at risk.
authors.affiliation: Department of Radiooncology and Radiotherapy, Community Hospital, Braunschweig, Germany. m.schiebe@klinikum.bs.shuttle.de
authors.forename: M
authors.initials: M
authors.lastname: Schiebe
authors.forename: W
authors.initials: W
authors.lastname: Hoffmann
mesh_terms: D005240:Feasibility Studies; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy; D008297:Male; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy; D011880:Radiotherapy Planning, Computer-Assisted / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012984:Software; D014057:Tomography, X-Ray Computed; D014584:User-Computer Interface