Development and validation of the Dynamic Collimation Monte Carlo simulation package for pencil beam scanning proton therapy.
Development and validation of the Dynamic Collimation Monte Carlo simulation package for pencil beam scanning proton therapy.
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笔形束扫描质子治疗动态准直蒙特卡罗模拟包的开发和验证。
DOI：
10.1002/mp.14846
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发表时间：
2021-06
期刊：
影响因子：
3.8
通讯作者：
Hill PM
中科院分区：
文献类型：
--
作者：
Nelson NP;Culberson WS;Hyer DE;Geoghegan TJ;Patwardhan KA;Smith BR;Flynn RT;Yu J;Rana S;Gutiérrez AN;Hill PM
这项工作的目的是开发和实验验证的动态准直蒙特卡罗（DCMC）模拟包专门设计的笔形束扫描质子治疗（PBS-PT）的准直器的模拟。DCMC包是使用TOPAS蒙特卡罗平台开发的，由广义PBS源模型和准直器组件扩展组成。创建了迈阿密癌症研究所（MCI）IBA专用喷嘴（DN）的发散点源模型，并根据MCI进行的轴上调试测量进行了验证。束线光学器件被数学地并入源中，以在相应的磁体平面处对X和Y方向上的子束偏转进行建模。在空气中的多个平面上进行的离轴测量用于验证源模型的离轴光斑尺寸和发散度。DCS微调器被建模并作为TOPAS几何形状扩展合并，其线性平移并围绕弯曲磁体旋转。为了验证准直器模型，在MCI获得了一系列积分深度剂量（IDD）和横向轮廓测量值，并用于基准DCMC性能，用于对原始和范围偏移的子束进行建模。水等效厚度（WET）的范围移位器的确定通过量化的范围移位和原始的未准直光束之间的布拉格峰远端的80%剂量点的深度的移位。IBA DN系统的源模型成功地调试了MCI进行的轴上和离轴IDD和横向剖面测量。通过优化源到轴的距离并与空气中的光斑轮廓进行比较，匹配了源模型的发散度。然后根据准直IDD和空气中以及体模中横向轮廓测量对DCS模型进行基准测试。伽马分析用于评价测量和模拟的侧向轮廓与IDD之间的一致性，标准为1%/1 mm，剂量阈值为1%。对于原始准直射束，在所有研究的准直器配置中，IDD的平均1%/1 mm伽马通过率为99.8%，空气中和体模中横向剖面的平均1%/1 mm伽马通过率为97.6%和95.2%。所有范围偏移准直IDD均100%通过，而空气中和体模中横向剖面的平均通过率分别为99.1%和99.8%。聚乙烯量程转换器的实测和模拟WET分别确定为40.9和41.0 mm。我们开发了一个基于TOPAS的蒙特卡罗软件包，用于模拟PBS-PT中的准直器。该软件包随后被委托使用非准直和准直测量对位于MCI的IBA DN系统和DCS进行建模。验证结果表明，DCMC包可以用来准确地模拟DCS实现的其他方面通过仿真。
The aim of this work was to develop and experimentally validate a Dynamic Collimation Monte Carlo (DCMC) simulation package specifically designed for the simulation of collimators in pencil beam scanning proton therapy (PBS-PT). The DCMC package was developed using the TOPAS Monte Carlo platform and consists of a generalized PBS source model and collimator component extensions. A divergent point-source model of the IBA dedicated nozzle (DN) at the Miami Cancer Institute (MCI) was created and validated against on-axis commissioning measurements taken at MCI. The beamline optics were mathematically incorporated into the source to model beamlet deflections in the X and Y directions at the respective magnet planes. Off-axis measurements taken at multiple planes in air were used to validate both the off-axis spot size and divergence of the source model. The DCS trimmers were modeled and incorporated as TOPAS geometry extensions that linearly translate and rotate about the bending magnets. To validate the collimator model, a series of integral depth dose (IDD) and lateral profile measurements were acquired at MCI and used to benchmark the DCMC performance for modeling both pristine and range shifted beamlets. The water equivalent thickness (WET) of the range shifter was determined by quantifying the shift in the depth of the 80% dose point distal to the Bragg peak between the range shifted and pristine uncollimated beams. A source model of the IBA DN system was successfully commissioned against on- and off-axis IDD and lateral profile measurements performed at MCI. The divergence of the source model was matched through an optimization of the source-to-axis distance and comparison against in-air spot profiles. The DCS model was then benchmarked against collimated IDD and in-air and in-phantom lateral profile measurements. Gamma analysis was used to evaluate the agreement between measured and simulated lateral profiles and IDDs with 1%/1 mm criteria and a 1% dose threshold. For the pristine collimated beams, the average 1%/1 mm gamma pass rates across all collimator configurations investigated were 99.8% for IDDs and 97.6% and 95.2% for in-air and in-phantom lateral profiles. All range shifted collimated IDDs passed at 100% while in-air and in-phantom lateral profiles had average pass rates of 99.1% and 99.8%, respectively. The measured and simulated WET of the polyethylene range shifter was determined to be 40.9 and 41.0 mm, respectively. We have developed a TOPAS-based Monte Carlo package for modeling collimators in PBS-PT. This package was then commissioned to model the IBA DN system and DCS located at MCI using both uncollimated and collimated measurements. Validation results demonstrate that the DCMC package can be used to accurately model other aspects of a DCS implementation via simulation.
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影响因子：
3.5
作者：
Lin, Liyong;Ainsley, Christopher G.;McDonough, James E.
通讯作者：
McDonough, James E.
DOI：
10.1016/j.ejmp.2017.01.011
发表时间：
2017-02-01
影响因子：
3.4
作者：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
Talla, Patrick Takoukam