title: Dosimetric verification of complex radiotherapy with a 3D optically based dosimetry system: dose painting and target tracking.
abstract: BACKGROUND
  The increasing complexity of radiotherapy (RT) has motivated research into three-dimensional (3D) dosimetry. In this study we investigate the use of 3D dosimetry with polymerizing gels and optical computed tomography (optical CT) as a verification tool for complex RT: dose painting and target tracking.
  
  
  METHODS
  For the dose painting studies, two dosimeters were irradiated with a seven-field intensity modulated radiotherapy (IMRT) plan with and without dose prescription based on a hypoxia image dataset of a head and neck patient. In the tracking experiments, two dosimeters were irradiated with a volumetric modulated arc therapy (VMAT) plan with and without clinically measured prostate motion and a third with both motion and target tracking. To assess the performance, 3D gamma analyses were performed between measured and calculated stationary dose distributions.
  
  
  RESULTS
  Gamma pass-rates of 95.3% and 97.3% were achieved for the standard and dose-painted IMRT plans. Gamma pass-rates of 91.4% and 54.4% were obtained for the stationary and moving dosimeter, respectively, while tracking increased the pass-rate for the moving dosimeter to 90.4%.
  
  
  CONCLUSIONS
  This study has shown that the 3D dosimetry system can reproduce and thus verify complex dose distributions, also when influenced by motion.
authors: Department of Medical Physics, Aarhus University/Aarhus University Hospital , Aarhus , Denmark.
authors: Peter S
authors: PS
authors: Skyt
authors: Jørgen B B
authors: JB
authors: Petersen
authors: Esben S
authors: ES
authors: Yates
authors: Per R
authors: PR
authors: Poulsen
authors: Thomas L
authors: TL
authors: Ravkilde
authors: Peter
authors: P
authors: Balling
authors: Ludvig P
authors: LP
authors: Muren
mesh_terms: D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided; D050397:Radiotherapy, Intensity-Modulated; D014057:Tomography, X-Ray Computed