Evaluation of the gamma dose distribution comparison method
Evaluation of the gamma dose distribution comparison method
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DOI：
10.1118/1.1598711
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发表时间：
2003-09-01
期刊：
影响因子：
3.8
通讯作者：
Dempsey, JF
中科院分区：
文献类型：
--
作者：
Low, DA;Dempsey, JF
伽马工具的开发是为了定量比较剂量分布，无论是测量或计算。在计算伽马之前，剂量和距离尺度的两个分布，被称为评估和参考，重新规范化的剂量和距离标准，分别。重整化允许沿剂量和距离轴沿着进行剂量分布比较。对于每个参考点独立计算的伽马量是在重正化多维空间中被评估的分布和参考点之间的最小距离。伽马量退化到剂量差异和距离协议测试在浅和非常陡峭的剂量梯度区域，分别。自引入以来，伽马量已被研究者用于评价剂量计算算法，并比较剂量测定测量。本文研究了二维伽马分布的行为，并在存在数据噪声的情况下评估了伽马分布。相对于无噪声条件，所评估的分布中的噪声导致伽马分布被低估。参考分布中的噪声与归一化剂量噪声成比例地增加伽马分布中的噪声。在典型的临床使用中，超过3%和3 mm的点的分数可能很大，因此我们通常在临床评价中使用5%和2-3 mm。对于临床病例，对于14.1 X 15.2 cm（2）射线照相胶片，在800 MHz Pentium 4上1 X 1 mm（2）插值分辨率的计算时间通常为5分钟。(C)2003年美国医学物理学家协会。
The gamma tool was developed to quantitatively compare dose distributions, either measured or calculated. Before computing gamma, the dose and distance scales of the two distributions, referred to as evaluated and reference, are renormalized by dose and distance criteria, respectively. The renormalization allows the dose distribution comparison to be conducted simultaneously along dose and distance axes. The gamma quantity, calculated independently for each reference point, is the minimum distance in the renormalized multidimensional space between the evaluated distribution and the reference point. The gamma quantity degenerates to the dose-difference and distance-to-agreement tests in shallow and very steep dose gradient regions, respectively. Since being introduced, the gamma quantity has been used by investigators to evaluate dose calculation algorithms, and compare dosimetry measurements. This manuscript examines the gamma distribution behavior in two dimensions and evaluates the gamma distribution in the presence of data noise. Noise in the evaluated distribution causes the gamma distribution to be underestimated relative to the no-noise condition. Noise in the reference distribution adds noise in the gamma distribution in proportion to the normalized dose noise. In typical clinical use, the fraction of points that exceed 3% and 3 mm can be extensive, so we typically use 5% and 2-3 mm in clinical evaluations. For clinical cases, the calculation time is typically 5 minutes for a 1 X 1 mm(2) interpolated resolution on an 800 MHz Pentium 4 for a 14.1 X 15.2 cm(2) radiographic film. (C) 2003 American Association of Physicists in Medicine.