Noninvasive eye localization in ocular proton therapy through optical eye tracking: A proof of concept

• DOI: 10.1002/mp.12841
• Publication Date: 2018-03-01T10:51:40Z
• Authors: Riccardo Via; Fabian Hennings; Giovanni Fattori; Aurora Fassi; Alessia Pica; Antony Lomax; Damien Charles Weber; Guido Baroni; Jan Hrbacek
• Keywords: Fiducial marker; Sclera; Scheimpflug principle

Purpose Over the last four decades, Ocular Proton Therapy has been successfully used to treat patients affected by intraocular lesions. For this, treatment geometry verification is routinely performed using radiographic images align a configuration of fiducial radiopaque markers implanted on sclera outer surface. This paper describes clinical application an alternative approach based optical eye tracking for three‐dimensional noninvasive and automatic localization. An experimental protocol was designed validate optical‐based referencing against both imaging system clinically EYEPLAN planning system. Methods The ( ETS ) installed in OPTIS 2 room at PSI acquire motions during nine patients. pupil position cornea curvature center were localized segmenting contour corneal light reflections acquired pair calibrated cameras. After calibration , direct comparison position, consequentially orientation, provided radiographs performed. Results Nineteen out thirty total monitored fractions excluded from study due poor visibility reflection, resulting success rate acquisition 37%. these data, overall median agreement between ‐based x‐ray‐based assessment 0.29 mm 0.94° translations rotations, respectively. Small discrepancies also measured estimates . Conversely, variations orientation higher, with interquartile range IQR 4.39° 7.58°. Nonetheless, dosimetric evaluation consequence uncertainties showed that target volume would still be covered more than 95% dose all cases. Conclusion ocular proton therapy monitor scenario. First results show potential such as localization device. However, low prevents straightforward needs further improvements aimed increasing reflection visibility.