Published in:
01-09-2014 | Original Research
A novel 2D/3D transformation for radiosurgery of ocular tumors: computer simulation and phantom validation
Published in: Journal of Radiation Oncology | Issue 3/2014
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Objective
Noninvasive stereotactic radiosurgery with the Cyberknife system has been seen as a promising treatment platform for ocular tumors in clinical practice. However, due to the unpredictable eye movement during treatment, 6D skull tracking cannot account for random ocular tumor positions and therefore compromise treatment delivery precision. A real-time ocular tumor tracking system is highly desirable.
Methods
We designed a novel “pupil tracking” approach that uses a derived 2D/3D transformation to relate the pupil’s 2D coordinate captured by a video camera in the image plane with the tumor’s 3D location in the CT space. To simulate and demonstrate the process of the 2D/3D transformation, a computer graphical model was created by using an interactive interface to mimic both tumor (size and location inside the eyeball) and eyeball (movement parameters). A mechanical phantom was also fabricated to validate the approach.
Results
Experimental data from computer simulation and phantom validation under the CT simulator were obtained. For eight testing points in the validation experiment by the mechanical phantom, the maximum root-sum-squared error (RSSE) of three coordinates (X, Y, Z) is less than 0.70 mm and the mean-squared error is 0.44 mm.
Conclusion
Error analysis indicates that this pupil tracking technique has a potential application for radiosurgery of ocular tumors by the Cyberknife system.