Comparison of the Batho, ETAR and Monte Carlo dose calculation methods in CT based patient models
Comparison of the Batho, ETAR and Monte Carlo dose calculation methods in CT based patient models
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DOI：
10.1118/1.1357223
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发表时间：
2001-04-01
期刊：
影响因子：
3.8
通讯作者：
Goedhals, L
中科院分区：
文献类型：
--
作者：
du Plessis, FCP;Willemse, CA;Goedhals, L
本文展示了蒙特卡罗方法在基于CT的患者模型中剂量分布计算方面的贡献，以及它作为评价其他剂量计算算法的金标准的作用。基于EGS4的BEAM代码构建了一个通用的8 MV加速器，获得了一系列的x射线场源。这些数据在基于EGS4的DOSXYZ代码中使用，在数学水影中生成光束数据，并在商业处理计划系统（TPS） CADPLAN V.2.7.9中建立光束模型。使用bath和ETAR不均匀校正算法计算2X 2、5X5和10X10 cm(2)开放x射线束在头部/鼻窦、肺部和前列腺患者模型中的剂量分布。以DOSXYZ为基准计算相应剂量分布。剂量比较用二维等剂量分布、百分比深度剂量数据和剂量差体积直方图（DDVH’s）表示。结果表明，在头部模型上颌窦区域，Bathe和ETAR方法的准确率为20%-70%。大的肺不均匀性以小场照射会引起10%-20%的吸收剂量偏差。结果显示，在10X10 cm(2)范围内，DOSXYZ可以模拟肺内的横向散射，而这在Batho和ETAR方法中是不存在的。ETAR和Bathe方法在前列腺模型中的准确率在3%以内。我们展示了如何使用经过验证的蒙特卡罗代码（如BEAM和DOSXYZ）在现实患者模型中理解这些非均匀性校正方法的性能。(C) 2001年美国医学物理学家协会。
This paper shows the contribution that Monte Carlo methods make in regard to dose distribution calculations in CT based patient models and the role it plays as a gold standard to evaluate other dose calculation algorithms. The EGS4 based BEAM code was used to construct a generic 8 MV accelerator to obtain a series of x-ray field sources. These were used in the EGS4 based DOSXYZ code to generate beam data in a mathematical water phantom to set up a beam model in a commercial treatment planning system (TPS), CADPLAN V.2.7.9. Dose distributions were calculated with the Bathe and ETAR inhomogeneity correction algorithms in head/sinus, lung, and prostate patient models for 2X 2, 5X5, and 10X10 cm(2) open x-ray beams. Corresponding dose distributions were calculated with DOSXYZ that were used as a benchmark. The dose comparisons are expressed in terms of 2D isodose distributions, percentage depth dose data, and dose difference volume histograms (DDVH's). Results indicated that the Bathe and ETAR methods contained inaccuracies of 20%-70% in the maxillary sinus region in the head model. Large lung inhomogeneities irradiated with small fields gave rise to absorbed dose deviations of 10%-20%. It is shown for a 10X10 cm(2) field that DOSXYZ models lateral scatter in lung that is not present in the Batho and ETAR methods. The ETAR and Bathe methods are accurate within 3% in a prostate model. We showed how the performance of these inhomogeneity correction methods can be understood in realistic patient models using validated Monte Carlo codes such as BEAM and DOSXYZ. (C) 2001 American Association of Physicists in Medicine.