A Monte‐Carlo‐based and <scp>GPU</scp>‐accelerated 4D‐dose calculator for a pencil beam scanning proton therapy system

Pepin, M.; Tryggestad, E.; Tseung, Hok Seum Wan Chan; Johnson, James L.; Herman, Michael; Beltran, Chris

doi:10.1002/mp.13182

Cited by 21 publications

(18 citation statements)

References 72 publications

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“…Current and future developments of our motion management program include the following: evaluating surface monitoring as a beam‐gating signal, exploring alternative rescanning techniques, and implementing practical 4D dosimetric verification tools. The evaluation of 4D robustness for esophageal plans was reported previously; more recently, a generalized 4D plan calculator (including dynamic interplay effect) accumulator based on our GPU‐based Monte Carlo dose algorithm has recently become available for clinical evaluation . This 4D GPU Monte Carlo calculation framework is currently being incorporated into a 4D robust plan optimization framework.…”

Section: Discussionmentioning

confidence: 98%

Clinical implementation of respiratory‐gated spot‐scanning proton therapy: An efficiency analysis of active motion management

Gelover

Deisher

Herman

et al. 2019

J Applied Clin Med Phys

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Purpose The aim of this work is to describe the clinical implementation of respiratory‐gated spot‐scanning proton therapy (SSPT) for the treatment of thoracic and abdominal moving targets. The experience of our institution is summarized, from initial acceptance and commissioning tests to the development of standard clinical operating procedures for simulation, motion assessment, motion mitigation, treatment planning, and gated SSPT treatment delivery. Materials and methods A custom respiratory gating interface incorporating the Real‐Time Position Management System (RPM, Varian Medical Systems, Inc., Palo Alto, CA, USA) was developed in‐house for our synchrotron‐based delivery system. To assess gating performance, a motion phantom and radiochromic films were used to compare gated vs nongated delivery. Site‐specific treatment planning protocols and conservative motion cutoffs were developed, allowing for free‐breathing (FB), breath‐holding (BH), or phase‐gating (Ph‐G). Room usage efficiency of BH and Ph‐G treatments was retrospectively evaluated using beam delivery data retrieved from our record and verify system and DICOM files from patient‐specific quality assurance (QA) procedures. Results More than 70 patients were treated using active motion management between the launch of our motion mitigation program in October 2015 and the end date of data collection of this study in January 2018. During acceptance procedures, we found that overall system latency is clinically‐suitable for Ph‐G. Regarding room usage efficiency, the average number of energy layers delivered per minute was <10 for Ph‐G, 10‐15 for BH and ≥15 for FB, making Ph‐G the slowest treatment modality. When comparing to continuous delivery measured during pretreatment QA procedures, the median values of BH treatment time were extended from 6.6 to 9.3 min (+48%). Ph‐G treatments were extended from 7.3 to 13.0 min (+82%). Conclusions Active motion management has been crucial to the overall success of our SSPT program. Nevertheless, our conservative approach has come with an efficiency cost that is more noticeable in Ph‐G treatments and should be considered in decision‐making.

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Section: Discussionmentioning

confidence: 98%

Clinical implementation of respiratory‐gated spot‐scanning proton therapy: An efficiency analysis of active motion management

Gelover

Deisher

Herman

et al. 2019

J Applied Clin Med Phys

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“…Therefore, it is important to consider the impact from both breathing and treatment uncertainties in the plan robustness evaluation simultaneously. 47,48 This comprehensive plan robustness evaluation would generate dose distributions that are more representative of the actual dose delivered in patients, providing more realistic dosimetric data for IMPT plan evaluation. Unfortunately this important topic has been rarely reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

Intensity‐modulated proton therapy (IMPT) interplay effect evaluation of asymmetric breathing with simultaneous uncertainty considerations in patients with non‐small cell lung cancer

et al. 2020

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Purpose Intensity‐modulated proton therapy (IMPT) is sensitive to uncertainties from patient setup and proton beam range, as well as interplay effect. In addition, respiratory motion may vary from cycle to cycle, and also from day to day. These uncertainties can severely degrade the original plan quality and potentially affect patient’s outcome. In this work, we developed a new tool to comprehensively consider the impact of all these uncertainties and provide plan robustness evaluation under them. Methods We developed a comprehensive plan robustness evaluation tool that considered both uncertainties from patient setup and proton beam range, as well as respiratory motion simultaneously. To mimic patients' respiratory motion, the time spent in each phase was randomly sampled based on patient‐specific breathing pattern parameters as acquired during the four‐dimensional (4D)‐computed tomography (CT) simulation. Spots were then assigned to one specific phase according to the temporal relationship between spot delivery sequence and patients’ respiratory motion. Dose in each phase was calculated by summing contributions from all the spots delivered in that phase. The final 4D dynamic dose was obtained by deforming all doses in each phase to the maximum exhalation phase. Three hundred (300) scenarios (10 different breathing patterns with 30 different setup and range uncertainty scenario combinations) were calculated for each plan. The dose‐volume histograms (DVHs) band method was used to assess plan robustness. Benchmarking the tool as an application’s example, we compared plan robustness under both three‐dimensional (3D) and 4D robustly optimized IMPT plans for 10 nonrandomly selected patients with non‐small cell lung cancer. Results The developed comprehensive plan robustness tool had been successfully applied to compare the plan robustness between 3D and 4D robustly optimized IMPT plans for 10 lung cancer patients. In the presence of interplay effect with uncertainties considered simultaneously, 4D robustly optimized plans provided significantly better CTV coverage (D95%, P = 0.002), CTV homogeneity (D5%‐D95%, P = 0.002) with less target hot spots (D5%, P = 0.002), and target coverage robustness (CTV D95% bandwidth, P = 0.004) compared to 3D robustly optimized plans. Superior dose sparing of normal lung (lung Dmean, P = 0.020) favoring 4D plans and comparable normal tissue sparing including esophagus, heart, and spinal cord for both 3D and 4D plans were observed. The calculation time for all patients included in this study was 11.4 ± 2.6 min. Conclusion A comprehensive plan robustness evaluation tool was successfully developed and benchmarked for plan robustness evaluation in the presence of interplay effect, setup and range uncertainties. The very high efficiency of this tool marks its clinical adaptation, highly practical and versatile nature, including possible real‐time intra‐fractional interplay effect evaluation as a potential application for future use.

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“…In order to estimate the 4D dynamic dose, an in-house 4D simulation program was used to incorporate experimentally validated synchrotron proton spot scanning timing parameters 37 and a GPU accelerated Monte Carlo dose calculation engine. 38 The in-house MC dose engine was benchmarked against GEANT4 simulations. The standard deviation of the disagreement of the models was found to be around 1% after accounting for the statistical uncertainties of…”

Section: E | Proton 4d Interplay Effect Simulationmentioning

confidence: 99%

Functional avoidance‐based intensity modulated proton therapy with 4DCT derived ventilation imaging for lung cancer

Dougherty

Castillo

et al. 2021

J Applied Clin Med Phys

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The primary objective is to evaluate the potential dosimetric gains of performing functional avoidance-based proton treatment planning using 4DCT derived ventilation imaging. 4DCT data of 31 patients from a prospective functional avoidance clinical trial were evaluated with intensity modulated proton therapy (IMPT) plans and compared with clinical volumetric modulated arc therapy (VMAT) plans. Dosimetric parameters were compared between standard and functional plans with IMPT and VMAT with one-way analysis of variance and post hoc paired student ttest. Normal Tissue Complication Probability (NTCP) models were employed to estimate the risk of two toxicity endpoints for healthy lung tissues. Dose degradation due to proton motion interplay effect was evaluated. Functional IMPT plans led to significant dose reduction to functional lung structures when compared with functional VMAT without significant dose increase to Organ at Risk (OAR) structures.When interplay effect is considered, no significant dose degradation was observed for the OARs or the clinical target volume (CTV) volumes for functional IMPT. Using fV20 as the dose metric and Grade 2+ pneumonitis as toxicity endpoint, there is a mean 5.7% reduction in Grade 2+ RP with the functional IMPT and as high as 26% in reduction for individual patient when compared to the standard IMPT planning.Functional IMPT was able to spare healthy lung tissue to avoid excess dose to normal structures while maintaining satisfying target coverage. NTCP calculation also shows that the risk of pulmonary complications can be further reduced with functional based IMPT.

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A Monte‐Carlo‐based and GPU‐accelerated 4D‐dose calculator for a pencil beam scanning proton therapy system

Cited by 21 publications

References 72 publications

Clinical implementation of respiratory‐gated spot‐scanning proton therapy: An efficiency analysis of active motion management

Clinical implementation of respiratory‐gated spot‐scanning proton therapy: An efficiency analysis of active motion management

Intensity‐modulated proton therapy (IMPT) interplay effect evaluation of asymmetric breathing with simultaneous uncertainty considerations in patients with non‐small cell lung cancer

Functional avoidance‐based intensity modulated proton therapy with 4DCT derived ventilation imaging for lung cancer

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