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Eye Tracking Based Navigation
for Proton Beam Therapy
PhD Thesis Defense
Presented by Stephan Wyder
| Faculty representative: |
Prof. Dr. Philippe C. Cattin |
| Co-referee: |
Prof. Dr. Raphael Sznitman |
| External expert: |
Prof. Dr. med. Francis Munier |
Men, 2013, Switzerland
Women, 2013, Switzerland
- Precise radiation dose delivery ✓
- Iterative tumor alignment with X-rays ❗
- Manual gazing control ❗
Is it possible to accurately localize and align the eye in a different way?
Model configuration 1:
- single camera
- single light source
⇒ Enables to localize eye center
c
Model configuration 2:
- multiple cameras
- multiple light sources
⇒ Better accuracy and robustness
- Data from construction plan
- Field of view optimization
- Eye tracker pose estimation
- Eye parameter estimation
All vectors in
R3
Input data:
-
from system calibration
-
from feature detection
Output data:
Further:
- Geometrical axis
- Visual axis / point of gaze
(li−oj)×(uij−oj)⏟wij∙(c−oj)=0
wij∙c−wij∙oj=0wTij⋅c=wij∙oj[[(lA1−oA)×(uA4−oA)]T[(lA1−oB)×(uB4−oB)]T⋮[(lB2−oA)×(uA1−oA)]T[(lB2−oB)×(uB2−oB)]T]⏟M2⋅c=[(lA1−oA)×(uA4−oA)∙oA(lA1−oB)×(uB4−oB)∙oB⋮(lB2−oA)×(uA1−oA)∙oA(lB2−oB)×(uB2−oB)∙oB]⏟hM2⋅c=hc=(MT2M2)−1⋅MT2h
Classical evaluation with volunteers.
Point of gaze accuracy:
0.96∘
Novel evaluation with an eye phantom.
Eye center accuracy (20 pos.):
0.68mm
Is it possible to accurately localize and align the eye in a different way?
Yes, it's possible!
Eye localization system:
- ✓ Integrated eye tracking system
- ✓ Validated system accuracy
- ⇒ Improving feature detection
- ⇒ Finding the optimal field of view
Improved navigation:
- ✓ Eye localization system, UniBasel
- ✓ Patient specific eye model, UniBern
- ⇒ Combination of both models, PSI
- ⇒ Clinical evaluation, PSI
Project partners:
Paul Scherrer Institute:
⇒ A. Lomax, J. Hrbacek, F. Hennings
University of Bern (Ophthalmic Technology Laboratory):
⇒ R. Sznitman, J. Kowal, S. de Zanet, C. Ciller, S. Apostolopoulos
Project support:
University of Basel (CIAN):
⇒ P. Cattin, S. Pezold
University of Basel (BMC):
⇒ B. Müller, G. Schulz
University Hospital Basel (Radiological Physics Group):
⇒ O. Bieri, F. Santini
AOT AG:
⇒ W. Deibel, A. Schneider
Project funding:
Swiss National Science Foundation
We support medical doctors
such that they can
optimally care about their patients!
We support medical doctors
such that they can optimally care about their patients!
