Shape Optimal Design of Leaf End for Multileaf Grating

Abstract

Abstract:

In order to improve dose delivery accuracy and reduce the dose error caused by penumbra, an analytical penumbra model was presented based on tangent secant theory. With penumbra width mean across radiation field set as objective function, leaf end shape optimization was proposed, which was applied for leaves in the shape of circular arc with center offset from the axis of leaf mean height. Furthermore, shape optimal design of leaf ends for on-axis and off-axis leaves was introduced. Results show that penumbra width mean is reduced by 1.6% for the optimized leaf end, compared with the method of maximum arc intersection radius.

Key words: multileaf collimator, leaf end, penumbra modelling, shape optimal design

摘要：

为提高放射治疗剂量的精度，减少因半影导致的剂量误差，引入切割线理论建立了半影解析表达模型。提出了以最大射野范围内半影宽度均值为优化目标，针对圆心偏置的圆弧类端面进行优化设计的方法，并将优化方法应用于中心叶片和离轴叶片的优化设计。结果表明：相比较最大圆弧相交半径法得到的端面形状，采用该算法优化后的叶片半影宽度均值减小了1.6%。

关键词: 多叶光栅, 叶片端面, 半影建模, 形状优化设计

CLC Number:

TH122
R815

Zhou Dong, Zhang Hui, Ye Peiqing. Shape Optimal Design of Leaf End for Multileaf Grating[J]. China Mechanical Engineering, 2016, 27(06): 737-742.

周东, 张辉, 叶佩青. 多叶光栅叶片端面形状优化设计[J]. 中国机械工程, 2016, 27(06): 737-742.

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