title: Eye tracking and gating system for proton therapy of orbital tumors.
abstract: OBJECTIVE
  A new motion-based gated proton therapy for the treatment of orbital tumors using real-time eye-tracking system was designed and evaluated.
  
  
  METHODS
  We developed our system by image-pattern matching, using a normalized cross-correlation technique with LabVIEW 8.6 and Vision Assistant 8.6 (National Instruments, Austin, TX). To measure the pixel spacing of an image consistently, four different calibration modes such as the point-detection, the edge-detection, the line-measurement, and the manual measurement mode were suggested and used. After these methods were applied to proton therapy, gating was performed, and radiation dose distributions were evaluated.
  
  
  RESULTS
  Moving phantom verification measurements resulted in errors of less than 0.1 mm for given ranges of translation. Dosimetric evaluation of the beam-gating system versus nongated treatment delivery with a moving phantom shows that while there was only 0.83 mm growth in lateral penumbra for gated radiotherapy, there was 4.95 mm growth in lateral penumbra in case of nongated exposure. The analysis from clinical results suggests that the average of eye movements depends distinctively on each patient by showing 0.44 mm, 0.45 mm, and 0.86 mm for three patients, respectively.
  
  
  CONCLUSIONS
  The developed automatic eye-tracking based beam-gating system enabled us to perform high-precision proton radiotherapy of orbital tumors.
authors: National Cancer Center, Goyang, Gyeonggi, Republic of Korea.
authors: Dongho
authors: D
authors: Shin
authors: Seung Hoon
authors: SH
authors: Yoo
authors: Sung Ho
authors: SH
authors: Moon
authors: Myonggeun
authors: M
authors: Yoon
authors: Se Byeong
authors: SB
authors: Lee
authors: Sung Yong
authors: SY
authors: Park
mesh_terms: D000465:Algorithms; D016477:Artifacts; D005133:Eye Movements; D005134:Eye Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D009038:Motion; D010363:Pattern Recognition, Automated / Q000379:methods*; D061766:Proton Therapy; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011522:Protons
chemical_list: D011522:Protons