GPU‐accelerated Monte Carlo‐based online adaptive proton therapy: A feasibility study

Feng, Hongying; Patel, Samir H.; Wong, William W.; Younkin, James E.; Penoncello, Gregory P.; Morales, Danairis Hernandez; Stoker, J.; Robertson, Daniel; Fatyga, M.; Bues, Martin; Schild, Steven E.; Foote, Robert L.; Liu, Wei

doi:10.1002/mp.15678

Cited by 16 publications

(16 citation statements)

References 74 publications

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“…The opensource fast MC code, MCsquare (2,17,18,20,43) has been thoroughly validated against other MC codes and measurements in both phantoms and patient geometries (2,18,(43)(44)(45)(46)(47)(48)(49). In addition, MCsquare has been fully commissioned and has been incorporated into our in-house treatment planning system, Shiva (6,19,(50)(51)(52)(53)(54)(55), and has been clinically used as the second monitor unit (MU) check system at our proton center for years (2,18) and other proton centers (56). Therefore, we chose MCsquare in this study as a fast Monte Carlo dose and linear energy transfer (LET) calculation engine.…”

Section: Methodsmentioning

confidence: 99%

Collimating individual beamlets in pencil beam scanning proton therapy, a dosimetric investigation

et al. 2022

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The purpose of this work is to investigate collimating individual proton beamlets from a dosimetric perspective and to introduce a new device concept, the spot scanning aperture (SSA). The SSA consists of a thin aperture with a small cylindrical opening attached to a robotics system, which allows the aperture to follow and align with individual beamlets during spot delivery. Additionally, a range shifter is incorporated (source-side) for treating shallow depths. Since the SSA trims beamlets spot by spot, the patient-facing portion of the device only needs to be large enough to trim a single proton beamlet. The SSA has been modelled in an open-source Monte-Carlo-based dose engine (MCsquare) to characterize its dosimetric properties in water at depths between 0 and 10 cm while varying the following parameters: the aperture material, thickness, distance to the water phantom, distance between the aperture and attached range shifter, and the aperture opening radius. Overall, the SSA greatly reduced spot sizes for all the aperture opening radii that were tested (1 – 4 mm), especially in comparison with the extended range shifter (ranger shifter placed at 30 cm from patient); greater than 50% when placed less than 10 cm away from the patient at depths in water less than 50 mm. The peak to entrance dose ratio and linear energy transfer was found to depend on the thickness of the aperture and therefore the aperture material. Neutron production rates were also investigated and discussed.

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Section: Methodsmentioning

confidence: 99%

Collimating individual beamlets in pencil beam scanning proton therapy, a dosimetric investigation

et al. 2022

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“…Future research should focus on identifying the optimal parameters for treatment planning to accelerate Monte Carlo dose calculation. The state-of -the-art GPU development 33,34 could be leveraged for the state-of -the-art deep learning frameworks, 35 auto-contour, and material characterization to enhance the efficiency and efficacy of the framework.…”

Section: Hnmentioning

confidence: 99%

An optimized framework for cone‐beam computed tomography‐based online evaluation for proton therapy

et al. 2023

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BackgroundClinical evidence has demonstrated that proton therapy can achieve comparable tumor control probabilities compared to conventional photon therapy but with the added benefit of sparing healthy tissues. However, proton therapy is sensitive to inter‐fractional anatomy changes. Online pre‐fraction evaluation can effectively verify proton dose before delivery to patients, but there is a lack of guidelines for implementing this workflow.PurposeThe purpose of this study is to develop a cone‐beam CT‐based (CBCT) online evaluation framework for proton therapy that enables knowledge transparency and evaluates the efficiency and accuracy of each essential component.MethodsTwenty‐three patients with various lesion sites were included to conduct a retrospective study of implementing the proposed CBCT evaluation framework for the clinic. The framework was implemented on the RayStation 11B Research platform. Two synthetic CT (sCT) methods, corrected CBCT (cCBCT), and virtual CT (vCT), were used, and the ground truth images were acquired from the same‐day deformed quality assurance CT (dQACT) for the comparisons. The evaluation metrics for the framework include time efficiency, dose‐difference distributions (gamma passing rates), and water equivalent thickness (WET) distributions.ResultsThe mean online CBCT evaluation times were 1.6 ± 0.3 min and 1.9 ± 0.4 min using cCBCT and vCT, respectively. The dose calculation and deformable image registration dominated the evaluation efficiency, and accounted for 33% and 30% of the total evaluation time, respectively. The sCT generation took another 19% of the total time. Gamma passing rates were greater than 91% and 97% using 1%/1 mm and 2%/2 mm criteria, respectively. When the appropriate sCT was chosen, the target mean WET difference from the reference were less than 0.5 mm. The appropriate sCT method choice determined the uncertainty for the framework, with the cCBCT being superior for head‐and‐neck patient evaluation and vCT being better for lung patient evaluation.ConclusionsAn online CBCT evaluation framework was proposed to identify the use of the optimal sCT algorithm regarding efficiency and dosimetry accuracy. The framework is extendable to adopt advanced imaging methods and has the potential to support online adaptive radiotherapy to enhance patient benefits. It could be implemented into clinical use in the future.

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“…The open-source fast MC code, MCsquare 35,[58][59][60][61] has been thoroughly validated against other MC codes and measurements in both phantoms and patient geometries. 58,59,[61][62][63][64][65][66][67] In addition, MCsquare has been fully commissioned and has been incorporated into our in-house TPS, Shiva, 51,[68][69][70][71][72] and has been clinically used as the second monitor unit (MU) check system at our proton center for years 59,61 and other proton centers. 73 Therefore, we chose MCsquare to generate all the PDFs used in the VPMC dose engine.…”

Section: Converting Realistic Particles To Vpsmentioning

confidence: 99%

Virtual particle Monte Carlo: A new concept to avoid simulating secondary particles in proton therapy dose calculation

et al. 2022

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Background In proton therapy dose calculation, Monte Carlo (MC) simulations are superior in accuracy but more time consuming, compared to analytical calculations. Graphic processing units (GPUs) are effective in accelerating MC simulations but may suffer thread divergence and racing condition in GPU threads that degrades the computing performance due to the generation of secondary particles during nuclear reactions. Purpose A novel concept of virtual particle (VP) MC (VPMC) is proposed to avoid simulating secondary particles in GPU‐accelerated proton MC dose calculation and take full advantage of the computing power of GPU. Methods Neutrons and gamma rays were ignored as escaping from the human body; doses of electrons, heavy ions, and nuclear fragments were locally deposited; the tracks of deuterons were converted into tracks of protons. These particles, together with primary and secondary protons, are considered to be the realistic particles. Histories of primary and secondary protons were replaced by histories of multiple VPs. Each VP corresponded to one proton (either primary or secondary). A continuous‐slowing‐down‐approximation model, an ionization model, and a large angle scattering event model corresponding to nuclear interactions were developed for VPs by generating probability distribution functions (PDFs) based on simulation results of realistic particles using MCsquare. For efficient calculations, these PDFs were stored in the Compute Unified Device Architecture textures. VPMC was benchmarked with TOPAS and MCsquare in phantoms and with MCsquare in 13 representative patient geometries. Comparisons between the VPMC calculated dose and dose measured in water during patient‐specific quality assurance (PSQA) of the selected 13 patients were also carried out. Gamma analysis was used to compare the doses derived from different methods and calculation efficiencies were also compared. Results Integrated depth dose and lateral dose profiles in both homogeneous and inhomogeneous phantoms all matched well among VPMC, TOPAS, and MCsquare calculations. The 3D–3D gamma passing rates with a criterion of 2%/2 mm and a threshold of 10% was 98.49% between MCsquare and TOPAS and 98.31% between VPMC and TOPAS in homogeneous phantoms, and 99.18% between MCsquare and TOPAS and 98.49% between VPMC and TOPAS in inhomogeneous phantoms, respectively. In patient geometries, the 3D–3D gamma passing rates with 2%/2 mm/10% between dose distributions from VPMC and MCsquare were 98.56 ± 1.09% in patient geometries. The 2D–3D gamma analysis with 3%/2 mm/10% between the VPMC calculated dose distributions and the 2D measured planar dose distributions during PSQA was 98.91 ± 0.88%. VPMC calculation was highly efficient and took 2.84 ± 2.44 s to finish for the selected 13 patients running on four NVIDIA Ampere GPUs in patient geometries. Conclusion VPMC was found to achieve high accuracy and efficiency in proton therapy dose calculation.

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GPU‐accelerated Monte Carlo‐based online adaptive proton therapy: A feasibility study

Cited by 16 publications

References 74 publications

Collimating individual beamlets in pencil beam scanning proton therapy, a dosimetric investigation

Collimating individual beamlets in pencil beam scanning proton therapy, a dosimetric investigation

An optimized framework for cone‐beam computed tomography‐based online evaluation for proton therapy

Virtual particle Monte Carlo: A new concept to avoid simulating secondary particles in proton therapy dose calculation

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