"Augmented reality" in conventional simulation by projection of 3-D structures into 2-D images: a comparison with virtual methods.
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.
Deutschmann
Heinz
H
University Clinic for Radiotherapy and Radio-Oncology, Salzburg, Austria. h.deutschmann@salk.at
Steininger
Philipp
P
Nairz
Olaf
O
Kopp
Peter
P
Merz
Florian
F
Wurstbauer
Karl
K
Zehentmayr
Franz
F
Fastner
Gerd
G
Kranzinger
Manfred
M
Kametriser
Gerhard
G
Kopp
Michael
M
Sedlmayer
Felix
F
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