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

Via, Riccardo; Hennings, Fabian; Fattori, Giovanni; Fassi, Aurora; Pica, Alessia; Lomax, Anthony; Weber, Damien Charles; Baroni, Guido; Hrbáček, Jan

doi:10.1002/mp.12841

Cited by 16 publications

(27 citation statements)

References 33 publications

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“…The improved ETS system described and analyzed here has a substantially increased acquisition success rate of 97% with respect to previous prototypes . The remaining 3% represents situations in which the number of established correspondence between infrared LEDs and corneal reflections were less than two and therefore hindered the measurement of the C point position.…”

Section: Discussionmentioning

confidence: 99%

“…In comparison to the system described in Ref. [] our second‐generation ETS prototype has been upgraded with a configuration of eight infrared LEDs in order to improve the glint detection rate (Fig. ), while still relying on three‐dimensional tracking of the pupil and cornea curvature center (P‐point and C‐point, respectively) .…”

Section: Methodsmentioning

confidence: 99%

“…ETS data acquisition was automatically triggered by a digital signal generated by a nozzle dose monitor and readout using a digital I/O device (NI‐USB‐6501, National Instruments, US). In addition, to guarantee geometrical consistency between ETS and the treatment room frame of reference, a calibration procedure based on a dedicated phantom was designed and implemented …”

Section: Methodsmentioning

confidence: 99%

“…Using this equation, the threshold for a target‐beam misalignment that should automatically trigger an interruption was determined as 0.71 mm, assuming 0.5 mm (based on x ray) and 1.0 mm for positioning and clinical uncertainties, respectively …”

Section: Methodsmentioning

confidence: 99%

“…Based on this, the beam is manually interrupted if relative motion is observed. While there have been several optical tracking methods proposed for automated monitoring of intrafractional motion a comprehensive study, including a comparison with the current clinical standard, has yet to be presented …”

Section: Introductionmentioning

confidence: 99%

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Technical Note: Benchmarking automated eye tracking and human detection for motion monitoring in ocular proton therapy

et al. 2020

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Purpose: Ocular proton therapy is an effective therapeutic option for patients affected with uveal melanomas. An optical eye-tracking system (ETS) aiming at noninvasive motion monitoring was developed and tested in a clinical scenario. Materials and methods: The ETS estimates eye position and orientation at 25 frames per second using the three-dimensional position of pupil and cornea curvature centers identified, in the treatment room, through stereoscopic optical imaging and infrared eye illumination. Its capabilities for automatic detection of eye motion were retrospectively evaluated on 60 treatment fractions. Then, the ETS performance was benchmarked against the clinical standard based on visual control and manual beam interruption. Results: Eye-tracking system detected eye position successfully in 97% of all available frames. Eyetracking system-based eye monitoring during therapy guarantees quicker response to involuntary eye motions than manual beam interruptions and avoids unnecessary beam interruptions. Conclusions: Eye-tracking system shows promise for on-line monitoring of eye motion. Its introduction in the clinical workflow will guarantee a swifter treatment course for the patient and the clinical personnel.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Technical Note: Benchmarking automated eye tracking and human detection for motion monitoring in ocular proton therapy

et al. 2020

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Three‐dimensional MRI‐based treatment planning approach for non‐invasive ocular proton therapy

et al. 2021

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Purpose To develop a high‐resolution three‐dimensional (3D) magnetic resonance imaging (MRI)‐based treatment planning approach for uveal melanomas (UM) in proton therapy. Materials/methods For eight patients with UM, a segmentation of the gross tumor volume (GTV) and organs‐at‐risk (OARs) was performed on T1‐ and T2‐weighted 7 Tesla MRI image data to reconstruct the patient MR‐eye. An extended contour was defined with a 2.5‐mm isotropic margin derived from the GTV. A broad beam algorithm, which we have called πDose, was implemented to calculate relative proton absorbed doses to the ipsilateral OARs. Clinically favorable gazing angles of the treated eye were assessed by calculating a global weighted‐sum objective function, which set penalties for OARs and extreme gazing angles. An optimizer, which we have named OPT’im‐Eye‐Tool, was developed to tune the parameters of the functions for sparing critical‐OARs. Results In total, 441 gazing angles were simulated for every patient. Target coverage including margins was achieved in all the cases (V95% > 95%). Over the whole gazing angles solutions space, maximum dose (Dmax) to the optic nerve and the macula, and mean doses (Dmean) to the lens, the ciliary body and the sclera were calculated. A forward optimization was applied by OPT’im‐Eye‐Tool in three different prioritizations: iso‐weighted, optic nerve prioritized, and macula prioritized. In each, the function values were depicted in a selection tool to select the optimal gazing angle(s). For example, patient 4 had a T2 equatorial tumor. The optimization applied for the straight gazing angle resulted in objective function values of 0.46 (iso‐weighted situation), 0.90 (optic nerve prioritization) and 0.08 (macula prioritization) demonstrating the impact of that angle in different clinical approaches. Conclusions The feasibility and suitability of a 3D MRI‐based treatment planning approach have been successfully tested on a cohort of eight patients diagnosed with UM. Moreover, a gaze‐angle trade‐off dose optimization with respect to OARs sparing has been developed. Further validation of the whole treatment process is the next step in the goal to achieve both a non‐invasive and a personalized proton therapy treatment.

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Modernization of safety environment for a dedicated beamline for proton ocular therapy

Jee,

Verburg,

Ruggieri

et al. 2023

Medical Physics

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BackgroundProton therapy is an effective treatment for ocular melanoma, and other tumors of the eye. The fixed horizontal beamline dedicated to ocular treatments at Massachusetts General Hospital was originally commissioned in 2002, with much of the equipment, safety features, and practices dating back to an earlier implementation at Harvard Cyclotron in the 1970s.PurposeTo describe the experience of reevaluation and enhancement of the safety environment for one of the longest continuously operating proton therapy programs.MethodsSeveral enhancements in quality control had been introduced throughout the years of operation, as described in this manuscript, to better align the practice with the evolving standards of proton therapy and the demands of a modern hospital. We spotlight the design and results of the failure mode and effect analysis (FMEA), and subsequent actions introduced to mitigate the modes associated with elevated risk. The findings of the FMEA informed the specifications for the new software application, which facilitated the improved management of the treatment workflow and the image‐guidance aspects of ocular treatments.ResultsEleven failure modes identified as having the highest risk are described. Six of these were mitigated with the clinical roll‐out of a new application for image‐guided radiation therapy (IGRT). Others were addressed through task automation, the broader introduction of checklists, and enhancements in pre‐treatment staff‐led time‐out.ConclusionsThroughout the task of modernizing the safety system of our dedicated ocular beamline, FMEA proved to be an effective instrument in soliciting inputs from the staff about safety and workflow concerns, helping to identify steps associated with elevated failure risks. Risks were reduced with the clinical introduction of a new IGRT application, which integrates quality management tools widely recognized for their role in risk mitigation: automation of the data transfer and workflow steps, and with the introduction of checklists and redundancy cross‐checks.

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

Cited by 16 publications

References 33 publications

Technical Note: Benchmarking automated eye tracking and human detection for motion monitoring in ocular proton therapy

Technical Note: Benchmarking automated eye tracking and human detection for motion monitoring in ocular proton therapy

Three‐dimensional MRI‐based treatment planning approach for non‐invasive ocular proton therapy

Modernization of safety environment for a dedicated beamline for proton ocular therapy

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