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

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

doi:10.1002/mp.14087

Cited by 9 publications

(5 citation statements)

References 21 publications

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“…This result emphasized the need for reliable, non-invasive alternative methods for positioning patients during proton therapy. To that end, Via et al and others have been developing eye-tracking-based methods to obviate clip surgery [21][22][23][24]. Moreover, for selected patients with larger UM tumors, alternative approaches might be available that are entirely non-invasive, like frameless stereotactic radiotherapy or Cyberknife treatment, which have acceptable QOL outcomes [25,26].…”

Section: Discussionmentioning

confidence: 99%

Quality of life and treatment-related burden during ocular proton therapy: a prospective trial of 131 patients with uveal melanoma

et al. 2021

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Background Proton beam therapy is a well-established treatment option for patients with uveal melanoma (UM). The treatment procedure, in general, includes placing radiopaque clips to ensure exact eye-positioning during radiotherapy, followed by the delivery of proton irradiation. The short-term burden associated with proton therapy in patients with UM has rarely been addressed. In this prospective study, we investigated the physiological and psychological aspects of proton therapy that might affect the well-being of patients during the different stages of treatment. Methods During the treatment procedure, we conducted longitudinal assessments of the Quality of life (QOL), organ-specific symptoms, and psychological aspects in patients with UM with three questionnaires (EORTC QLQ-C30, EORTC QLQ-OPT30, and GAD-7). Patients completed questionnaires before clip surgery (T0), before proton therapy (T1), after completing treatment (T2), and three months after treatment completion (T3). We also collected data on tumor characteristics and socio-demographics to identify potential risk factors associated with high treatment burdens. Results We prospectively included 131 consecutive patients. Questionnaire data showed a significant, temporary decline in global QOL and an increase in eye-related symptoms, as a result of the clip surgery (T0–T1). After treatment completion (T2), global QOL improved gradually, and none of the eye-related symptoms significantly deteriorated over the course of proton therapy. The global QOL returned to baseline levels three months after treatment (T3). We identified baseline anxiety as an independent risk factor for experiencing an acute treatment-related burden. Furthermore, we found interactions between GAD7 and patient sex showing that anxiety had a more pronounced effect on QOL outcome in female patients. Conclusion The short-term treatment-related burden of ocular proton therapy appeared to be largely associated with the preceding clip surgery, rather than the irradiation procedure. We found that anxiety was strongly associated with experiencing QOL issues during the treatment procedure. Our findings could contribute to the development of future strategies for improving the treatment process and psycho-oncologic patient care.

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Section: Discussionmentioning

confidence: 99%

Quality of life and treatment-related burden during ocular proton therapy: a prospective trial of 131 patients with uveal melanoma

et al. 2021

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“…A new treatment plan, with the dose distribution optimized on TV MR was generated, and the coverage of TV EP assessed. The dose distribution on TV EP was also evaluated by doubling the component of the margin accounting for clinical uncertainties, according to [17], resulting in a total of 4 mm instead of 2.5 mm. This was applied isotropically to the MRI-defined target.…”

Section: Dosimetric Evaluationmentioning

confidence: 99%

Potential and pitfalls of 1.5T MRI imaging for target volume definition in ocular proton therapy

Via

Hennings

Pica

et al. 2021

Radiotherapy and Oncology

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Introduction: Ocular proton therapy (OPT) for the treatment of uveal melanoma has a long and remarkably successful history. This is despite that, for the majority of patients treated, the definition of the eye anatomy is based on a simplified geometrical model embedded in the treatment planning system EyePlan. In this study, differences in anatomical and tumor structures from EyePlan, and those based on 1.5T magnetic resonance imaging (MRI) are assessed. Materials and methods: Thirty-three uveal melanoma patients treated with OPT at our institution were subject to eye MRI. The target volumes were manually delineated on those images by two radiation oncologists. The resulting volumes were geometrically compared to the clinical standard. In addition, the dosimetric impact of using different models for treatment planning were evaluated. Results: Two patients (6%) presented lesions too small to be visible on MRI. Target volumes identified on MRI scans were on average smaller than EyePlan with discrepancies arising mostly from the definition of the tumor base. Clip-to-tumor base distances measured on MRI models exhibited higher discrepancy to ophthalmological measurements than EyePlan. For 53% of cases, treatment plans optimized for lesions identified on MRI only, failed to achieve sufficient target coverage for EyePlan volumes. Discussion: The analysis has shown that 1.5T MRI might be more susceptible to misses of flat tumor extension of the clinical target volume than the current clinical standard. Thus, a proper integration of ancillary imaging modalities, leading to a better characterization of the full lesion, is required.

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“…To achieve this, not only an MRI‐based TPS is needed but also a real time eye detection system for gazing angle position verification before and during the treatment 58 . At both Centro Nazionale di Adroterapia Oncologica (CNAO, Pavia, Italy) and Paul Scherrer Institute, eye tracking systems have been embedded for controlling the gaze direction during the treatment fraction 59–62 . An infrared optical tracking‐based camera system is also under development within a broader collaboration of this project for Image Guidance Proton Therapy (IGPT).…”

Section: Discussionmentioning

confidence: 99%

“…58 At both Centro Nazionale di Adroterapia Oncologica (CNAO, Pavia, Italy) and Paul Scherrer Institute, eye tracking systems have been embedded for controlling the gaze direction during the treatment fraction. [59][60][61][62] An infrared optical tracking-based camera system is also under development within a broader collaboration of this project for Image Guidance Proton Therapy (IGPT). The clinical implementation of any of the investigated systems will lead to avoiding the use of surgical clips (tantalum, 2.5-mm diameter, 0.17-mm thickness), which cause dose uncertainties behind and/or nearby due to the high density of tantalum if located in the beam path.…”

Section: Discussionmentioning

confidence: 99%

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

Cited by 9 publications

References 21 publications

Quality of life and treatment-related burden during ocular proton therapy: a prospective trial of 131 patients with uveal melanoma

Quality of life and treatment-related burden during ocular proton therapy: a prospective trial of 131 patients with uveal melanoma

Potential and pitfalls of 1.5T MRI imaging for target volume definition in ocular proton therapy

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

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