Characterization of the HollandPTC proton therapy beamline dedicated to uveal melanoma treatment and an interinstitutional comparison

Fleury, E.; Trnková, Petra; Spruijt, Kees; Hérault, J.; Lebbink, Franciska; Heufelder, Jens; Hrbáček, Jan; Horwacik, Tomasz; Kajdrowicz, Tomasz; Denker, A.; Gérard, A.; Hofverberg, P.; Mamalui, M; Slopsema, R; Pignol, Jean-Philippe; Hoogeman, M.

doi:10.1002/mp.15024

Cited by 16 publications

(30 citation statements)

References 77 publications

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“…The values in Table 1 were chosen to represent possible beam qualities used in ocular PT [6][7][8][9]21,22 with DFO and LPs ranging from 1 to 4 mm. Model #1 was considered as the technical lower limit, while model #9 on the other hand represents a combination, that may result from a cyclotron-based PBS system with a static aperture.…”

Section: In Silico Modeling Of Proton Distributions Using Rayocularmentioning

confidence: 99%

“…Those two parameters depend on the accelerator and beam delivery technique used and may both vary between 1 and 3 mm for dedicated eye treatment nozzles. [6][7][8] The lateral spreading of the proton beam is typically achieved by a single-or doublescattering systems. The pencil-beam scanning (PBS) technique with apertures can in principle be applied as well.…”

Section: Introductionmentioning

confidence: 99%

“…In a recent interinstitutional comparison it was concluded that clinical outcomes are highly dependent on the centers'beam properties. 7 Weber et al 13 compared different radio-therapy modalities and showed the general benefit of ocular PT with a dedicated scattering nozzle. However, the modeling accuracy of the Paul-Scherrer Institute (PSI) OPTIS system in this planning study was limited as the beam model was simplified by neglecting collimation.…”

Section: Introductionmentioning

confidence: 99%

“…The dose distribution of a laterally collimated broad beam spread‐out Bragg‐peak (SOBP) is typically characterized in terms of lateral penumbra (LP) and distal fall‐off (DFO). Those two parameters depend on the accelerator and beam delivery technique used and may both vary between 1 and 3 mm for dedicated eye treatment nozzles 6–8 . The lateral spreading of the proton beam is typically achieved by a single‐ or double‐scattering systems.…”

Section: Introductionmentioning

confidence: 99%

“…Although the benefit of a sharp LP/DFO is obvious in order to protect neighboring OARs, it is not clear how this exactly translates into plan quality. In a recent interinstitutional comparison it was concluded that clinical outcomes are highly dependent on the centers’ beam properties 7 . Weber et al 13 .…”

Section: Introductionmentioning

confidence: 99%

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Technical note: Impact of beam properties for uveal melanoma proton therapy—An in silico planning study

et al. 2022

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Purpose To evaluate the impact of beam quality in terms of distal fall‐off (DFO, 90%–10%) and lateral penumbra (LP, 80%–20%) of single beam ocular proton therapy (OPT) and to derive resulting ideal requirements for future systems. Methods Nine different beam models with DFO varying between 1 and 4 mm and LP between 1 and 4 mm were created. Beam models were incorporated into the RayStation with RayOcular treatment planning system version 10 B (RaySearch Laboratories, Stockholm, Sweden). Each beam model was applied for eight typical clinical cases, covering different sizes and locations of uveal melanoma. Plans with and without an additional wedge were created, resulting in 117 plans with a total prescribed median dose of 60 Gy(RBE) to the clinical target volume. Treatment plans were analyzed in terms of V20–V80 penumbra volume, D1 (dose to 1% of the volume) for optic disc and macula, optic nerve V30 (volume receiving 30 Gy(RBE), i.e., 50% of prescription), as well as average dose to lens and ciliary body. An LP‐dependent aperture margin was based on estimated uncertainties, ranging from 1.7 to 4.0 mm. Results V20–V80 showed a strong influence by LP, while DFO was less relevant. The optic disc D1 reached an extra dose of up to 3000 cGy(RBE), comparing the defined technical limit of DFO = LP = 1 mm with DFO = 3 mm/LP = 4 mm. The latter may result from a pencil‐beam scanning (PBS) system with static apertures. Plans employing a wedge showed an improvement for organs at risk sparing. Conclusion Plan quality is strongly influenced by initial beam parameters. The impact of LP is more pronounced when compared to DFO. The latter becomes important in the treatment of posterior tumors near the macula, optic disc or optic nerve. The plan quality achieved by dedicated OPT nozzles in single‐ or double‐scattering design might not be achievable with modified PBS systems.

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Section: In Silico Modeling Of Proton Distributions Using Rayocularmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Technical note: Impact of beam properties for uveal melanoma proton therapy—An in silico planning study

et al. 2022

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Comprehensive investigation of lateral dose profile and output factor measurements in small proton fields from different delivery techniques

et al. 2023

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Background and purpose As a part of the commissioning and quality assurance in proton beam therapy, lateral dose profiles and output factors have to be acquired. Such measurements can be performed with point detectors and are especially challenging in small fields or steep lateral penumbra regions as the detector's volume effect may lead to perturbations. To address this issue, this work aims to quantify and correct for such perturbations of six point detectors in small proton fields created via three different delivery techniques. Methods Lateral dose profile and output measurements of three proton beam delivery techniques (pencil beam scanning, pencil beam scanning combined with collimators, passive scattering with collimators) were performed using high‐resolution EBT3 films, a PinPoint 3D 31022 ionization chamber, a microSilicon diode 60023 and a microDiamond detector 60019 (all PTW Freiburg, Germany). Detector specific lateral dose response functions K(x,y) acting as the convolution kernel transforming the undisturbed dose distribution D(x,y) into the measured signal profiles M(x,y) were applied to quantify perturbations of the six investigated detectors in the proton fields and correct the measurements. A signal theoretical analysis in Fourier space of the dose distributions and detector's K(x,y) was performed to aid the understanding of the measurement process with regard to the combination of detector choice and delivery technique. Results Quantification of the lateral penumbra broadening and signal reduction at the fields center revealed that measurements in the pencil beam scanning fields are only compromised slightly even by large volume ionization chambers with maximum differences in the lateral penumbra of 0.25 mm and 4% signal reduction at the field center. In contrast, radiation techniques with collimation are not accurately represented by the investigated detectors as indicated by a penumbra broadening up to 1.6 mm for passive scattering with collimators and 2.2 mm for pencil beam scanning with collimators. For a 3 mm diameter collimator field, a signal reduction at field center between 7.6% and 60.7% was asserted. Lateral dose profile measurements have been corrected via deconvolution with the corresponding K(x,y) to obtain the undisturbed D(x,y). Corrected output ratios of the passively scattered collimated fields obtained for the microDiamond, microSilicon and PinPoint 3D show agreement better than 0.9% (one standard deviation) for the smallest field size of 3 mm. Conclusion Point detector perturbations in small proton fields created with three delivery techniques were quantified and found to be especially pronounced for collimated small proton fields with steep dose gradients. Among all investigated detectors, the microSilicon diode showed the smallest perturbations. The correction strategies based on detector's K(x,y) were found suitable for obtaining unperturbed lateral dose profiles and output factors. Approximation of K(x,y) by considering only the geometrical averaging effect has ...

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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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Characterization of the HollandPTC proton therapy beamline dedicated to uveal melanoma treatment and an interinstitutional comparison

Cited by 16 publications

References 77 publications

Technical note: Impact of beam properties for uveal melanoma proton therapy—An in silico planning study

Technical note: Impact of beam properties for uveal melanoma proton therapy—An in silico planning study

Comprehensive investigation of lateral dose profile and output factor measurements in small proton fields from different delivery techniques

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

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