Evaluation of motion mitigation using abdominal compression in the clinical implementation of pencil beam scanning proton therapy of liver tumors

Lin, Liyong; Souris, Kevin; Kang, Minglei; Glick, Adam; Lin, Haibo; Huang, Sheng; Stützer, Kristin; Janssens, Guillaume; Sterpin, Edmond; Lee, John A.; Solberg, Timothy D.; McDonough, James E.; Simone, Charles B.; Ben‐Josef, Edgar

doi:10.1002/mp.12040

Cited by 60 publications

(58 citation statements)

References 42 publications

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“…Validation and clinical implementation of fast MC can potentially facilitate routine treatment plan quality assurance,18, 19 and bring 4D dynamic dose (4DDD) MC engines from conceptual research to clinical practices,20, 21, 22 when the dosimetric accuracy of analytical dose engines are challenged for the cases of heterogeneous tissue or with involvement of range shifter/patient bolus and large air gap.…”

Section: Introductionmentioning

confidence: 99%

Validation and clinical implementation of an accurate Monte Carlo code for pencil beam scanning proton therapy

Huang

Kang

Souris

et al. 2018

J Applied Clin Med Phys

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Monte Carlo (MC)‐based dose calculations are generally superior to analytical dose calculations (ADC) in modeling the dose distribution for proton pencil beam scanning (PBS) treatments. The purpose of this paper is to present a methodology for commissioning and validating an accurate MC code for PBS utilizing a parameterized source model, including an implementation of a range shifter, that can independently check the ADC in commercial treatment planning system (TPS) and fast Monte Carlo dose calculation in opensource platform (MCsquare). The source model parameters (including beam size, angular divergence and energy spread) and protons per MU were extracted and tuned at the nozzle exit by comparing Tool for Particle Simulation (TOPAS) simulations with a series of commissioning measurements using scintillation screen/CCD camera detector and ionization chambers. The range shifter was simulated as an independent object with geometric and material information. The MC calculation platform was validated through comprehensive measurements of single spots, field size factors (FSF) and three‐dimensional dose distributions of spread‐out Bragg peaks (SOBPs), both without and with the range shifter. Differences in field size factors and absolute output at various depths of SOBPs between measurement and simulation were within 2.2%, with and without a range shifter, indicating an accurate source model. TOPAS was also validated against anthropomorphic lung phantom measurements. Comparison of dose distributions and DVHs for representative liver and lung cases between independent MC and analytical dose calculations from a commercial TPS further highlights the limitations of the ADC in situations of highly heterogeneous geometries. The fast MC platform has been implemented within our clinical practice to provide additional independent dose validation/QA of the commercial ADC for patient plans. Using the independent MC, we can more efficiently commission ADC by reducing the amount of measured data required for low dose “halo” modeling, especially when a range shifter is employed.

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Section: Introductionmentioning

confidence: 99%

Validation and clinical implementation of an accurate Monte Carlo code for pencil beam scanning proton therapy

Huang

Kang

Souris

et al. 2018

J Applied Clin Med Phys

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“…There are several techniques to mitigate breathing motion and minimize the dose degradation due to the interplay effect. Examples are rescanning, tracking, gating, and abdominal compression . The breath‐hold technique is a technique investigated initially for breast cancer patients, and later also for NSCLC patients .…”

Section: Introductionmentioning

confidence: 99%

Reproducibility of the lung anatomy under active breathing coordinator control: Dosimetric consequences for scanned proton treatments

et al. 2018

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“…To assess the dose degradation due to potential interplay effects, the 4D dose calculation should take into account the dynamic of the delivery equipment. The simulation of the interplay effect has already been described in the literature, using various methods to reconstruct the delivery timing information. In our implementation, the IBA software ScanAlgo is employed to simulate the delivery process and extract the delivery time and duration for each spot of the PBS plan.…”

Section: Methodsmentioning

confidence: 99%

“…Motion further complicates the situation of knowing the exact stopping location of ions . The breathing motion causes the geometrical shift of the target with respect to the dose distribution.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, natural variations of the breathing motion should be incorporated together with a quantified assessment of the interplay effect. Effects of interplay have already been studied in the past, but not in combination with all other treatment uncertainties. To assess the combined effect of these errors, all treatment uncertainty models should be mixed in a combinatorial and statistically consistent way.…”

Section: Introductionmentioning

confidence: 99%

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Technical Note: Monte Carlo methods to comprehensively evaluate the robustness of 4D treatments in proton therapy

et al. 2019

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Introduction Proton therapy is very sensitive to treatment uncertainties. These uncertainties can induce proton range variations and may lead to severe dose distortions. However, most commercial tools only offer a limited integration of these uncertainties during treatment planning. In order to verify the robustness of a treatment plan, this study aims at developing a comprehensive Monte Carlo simulation of the treatment delivery, including the simulation of setup and range errors, variation of the breathing motion, and interplay effect. Method Most clinically relevant uncertainties have been modeled and implemented in the fast Monte Carlo dose engine MCsquare. Especially, variation of the breathing motion is taken into account by deforming the initial Four‐dimensional computed tomography (4DCT) series and generating multiple new 4DCT series with scaled motion. Systematic and random errors are randomly sampled, following a Monte Carlo approach, to generate individual erroneous treatment scenarios. The robustness of treatment plans is analyzed and reported with dose‐volume histogram (DVH) bands. The statistical uncertainty coming from the Monte Carlo scenario sampling is studied. Results A validation demonstrated the ability of the motion model to generate new 4DCT series with scaled motion amplitude and improved image quality in comparison to the initial 4DCT. The robustness analysis is applied to a lung tumor treatment. Considering the proposed uncertainty model, the simulation of 300 treatment scenarios was necessary to reach an acceptable level of statistical uncertainty on the DVH band. Conclusion A comprehensive and statistically sound method of treatment plan robustness verification is proposed. The uncertainty model presented in this paper is not specific to protons and can also be applied to photon treatments. Moreover, the generated 4DCT series, with scaled motion, can be imported in commercial TPSs.

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Evaluation of motion mitigation using abdominal compression in the clinical implementation of pencil beam scanning proton therapy of liver tumors

Abstract: A workflow for screening patients' motion characteristics and optimizing beam angle selection was established for the pencil beam scanning proton therapy treatment of liver tumors. Abdominal compression was found to be useful at mitigation of moderate and large motion.

Cited by 60 publications

References 42 publications

Validation and clinical implementation of an accurate Monte Carlo code for pencil beam scanning proton therapy

Validation and clinical implementation of an accurate Monte Carlo code for pencil beam scanning proton therapy

Reproducibility of the lung anatomy under active breathing coordinator control: Dosimetric consequences for scanned proton treatments

Technical Note: Monte Carlo methods to comprehensively evaluate the robustness of 4D treatments in proton therapy

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