title: Monitoring tumor motion by real time 2D/3D registration during radiotherapy.
abstract: OBJECTIVE
  In this paper, we investigate the possibility to use X-ray based real time 2D/3D registration for non-invasive tumor motion monitoring during radiotherapy.
  
  
  METHODS
  The 2D/3D registration scheme is implemented using general purpose computation on graphics hardware (GPGPU) programming techniques and several algorithmic refinements in the registration process. Validation is conducted off-line using a phantom and five clinical patient data sets. The registration is performed on a region of interest (ROI) centered around the planned target volume (PTV).
  
  
  RESULTS
  The phantom motion is measured with an rms error of 2.56 mm. For the patient data sets, a sinusoidal movement that clearly correlates to the breathing cycle is shown. Videos show a good match between X-ray and digitally reconstructed radiographs (DRR) displacement. Mean registration time is 0.5 s.
  
  
  CONCLUSIONS
  We have demonstrated that real-time organ motion monitoring using image based markerless registration is feasible.
authors: Center of Medical Physics and Biomedical Engineering, Medical University of Vienna, Austria.
authors: Christelle
authors: C
authors: Gendrin
authors: Hugo
authors: H
authors: Furtado
authors: Christoph
authors: C
authors: Weber
authors: Christoph
authors: C
authors: Bloch
authors: Michael
authors: M
authors: Figl
authors: Supriyanto Ardjo
authors: SA
authors: Pawiro
authors: Helmar
authors: H
authors: Bergmann
authors: Markus
authors: M
authors: Stock
authors: Gabor
authors: G
authors: Fichtinger
authors: Dietmar
authors: D
authors: Georg
authors: Wolfgang
authors: W
authors: Birkfellner
mesh_terms: D000465:Algorithms; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D009038:Motion; D019047:Phantoms, Imaging; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed