title: "Augmented reality" in conventional simulation by projection of 3-D structures into 2-D images: a comparison with virtual methods.
abstract: OBJECTIVE
  In this study, a new method is introduced, which allows the overlay of three-dimensional structures, that have been delineated on transverse slices, onto the fluoroscopy from conventional simulators in real time.
  
  
  METHODS
  Setup deviations between volumetric imaging and simulation were visualized, measured and corrected for 701 patient isocenters.
  
  
  RESULTS
  Comparing the accuracy to mere virtual simulation lacking additional X-ray imaging, a clear benefit of the new method could be shown. On average, virtual prostate simulations had to be corrected by 0.48 cm (standard deviation [SD] 0.38), and those of the breast by 0.67 cm (SD 0.66).
  
  
  CONCLUSIONS
  The presented method provides an easy way to determine entity-specific safety margins related to patient setup errors upon registration of bony anatomy (prostate 0.9 cm for 90% of cases, breast 1.3 cm). The important role of planar X-ray imaging was clearly demonstrated. The innovation can also be applied to adaptive image-guided radiotherapy (IGRT) protocols.
authors.affiliation: University Clinic for Radiotherapy and Radio-Oncology, Salzburg, Austria. h.deutschmann@salk.at
authors.forename: Heinz
authors.initials: H
authors.lastname: Deutschmann
authors.forename: Philipp
authors.initials: P
authors.lastname: Steininger
authors.forename: Olaf
authors.initials: O
authors.lastname: Nairz
authors.forename: Peter
authors.initials: P
authors.lastname: Kopp
authors.forename: Florian
authors.initials: F
authors.lastname: Merz
authors.forename: Karl
authors.initials: K
authors.lastname: Wurstbauer
authors.forename: Franz
authors.initials: F
authors.lastname: Zehentmayr
authors.forename: Gerd
authors.initials: G
authors.lastname: Fastner
authors.forename: Manfred
authors.initials: M
authors.lastname: Kranzinger
authors.forename: Gerhard
authors.initials: G
authors.lastname: Kametriser
authors.forename: Michael
authors.initials: M
authors.lastname: Kopp
authors.forename: Felix
authors.initials: F
authors.lastname: Sedlmayer
mesh_terms: D003198:Computer Simulation; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008954:Models, Biological; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011881:Radiotherapy, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014584:User-Computer Interface