A quantitative method to the analysis of MLC leaf position and speed based on EPID and EBT3 film for dynamic IMRT treatment with different types of MLC.
A quantitative method to the analysis of MLC leaf position and speed based on EPID and EBT3 film for dynamic IMRT treatment with different types of MLC.
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DOI：
10.1002/acm2.12102
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发表时间：
2017-07
影响因子：
2.1
通讯作者：
Liu X
中科院分区：
文献类型：
--
作者：
Li Y;Chen L;Zhu J;Wang B;Liu X
开发了一种基于电子射野成像系统（EPID）和胶片的定量方法，用于MLC位置和速度测试;该方法用于三种MLC类型（Millennium、MLCi和Agility MLC）。为了确定叶片位置，使用了由动态模型（DMLC）设计的栅栏。使用FWHM与标称间隙宽度关系，将EPID和EBT 3测量的每个间隙的半高全宽（FWHM）值转换为差距宽度。为栅栏分析开发的算法能够量化差距宽度、间隙之间的距离和每个单独的叶片位置。为确定叶片速度，在14 × 20 cm 2对称射野上应用0.5 × 20 cm 2 MLC定义的滑动间隙。直线加速器以固定剂量率运行本测试使用不同的监测单元（MU）导致不同的叶片速度。在速度精度分析中考虑了叶片传动的影响。MLC位置的EPID和胶片结果之间的差异小于0.1 mm。对于三种MLC类型，提供两倍标准差（2 SD）;三种MLC类型的间隙宽度为0.2、0.4和0.4 mm，间隙之间的距离为0.1、0.2和0.2 mm。单个叶片位置偏离预设位置在0.1 mm内。EPID和EBT 3结果的速度曲线变化是一致的，但EPID结果略好于胶片结果。测量了每种MLC类型的不同速度。对于所有三种MLC类型，速度误差随着速度的增加而增加。分析速度与预设速度的偏差约为0.01 cm s-1。这种MLC位置和速度的定量分析为MLC质量保证（QA）提供了直观的评估。
A quantitative method based on the electronic portal imaging system (EPID) and film was developed for MLC position and speed testing; this method was used for three MLC types (Millennium, MLCi, and Agility MLC). To determine the leaf position, a picket fence designed by the dynamic (DMLC) model was used. The full‐width half‐maximum (FWHM) values of each gap measured by EPID and EBT3 were converted to the gap width using the FWHM versus nominal gap width relationship. The algorithm developed for the picket fence analysis was able to quantify the gap width, the distance between gaps, and each individual leaf position. To determine the leaf speed, a 0.5 × 20 cm2 MLC‐defined sliding gap was applied across a 14 × 20 cm2 symmetry field. The linacs ran at a fixed‐dose rate. The use of different monitor units (MUs) for this test led to different leaf speeds. The effect of leaf transmission was considered in a speed accuracy analysis. The difference between the EPID and film results for the MLC position is less than 0.1 mm. For the three MLC types, twice the standard deviation (2 SD) is provided; 0.2, 0.4, and 0.4 mm for gap widths of three MLC types, and 0.1, 0.2, and 0.2 mm for distances between gaps. The individual leaf positions deviate from the preset positions within 0.1 mm. The variations in the speed profiles for the EPID and EBT3 results are consistent, but the EPID results are slightly better than the film results. Different speeds were measured for each MLC type. For all three MLC types, speed errors increase with increasing speed. The analysis speeds deviate from the preset speeds within approximately 0.01 cm s−1. This quantitative analysis of MLC position and speed provides an intuitive evaluation for MLC quality assurance (QA).
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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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DOI：
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发表时间：
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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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