High density dental materials and radiotherapy planning: Comparison of the dose predictions using superposition algorithm and fluence map Monte Carlo method with radiochromic film measurements
High density dental materials and radiotherapy planning: Comparison of the dose predictions using superposition algorithm and fluence map Monte Carlo method with radiochromic film measurements
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DOI：
10.1016/j.radonc.2006.10.010
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发表时间：
2006-12-01
影响因子：
5.7
通讯作者：
Thai, Van
中科院分区：
文献类型：
--
作者：
Spirydovich, Siarhei;Papiez, Lech;Thai, Van
背景和目的：在放射治疗计划高密度牙科材料创建一个主要的挑战，在确定正确的剂量分布内的患者与头颈tumors.Patients和方法：在这项工作中，我们调查了吸收剂量分布内的固体水（（R））刺幻影嵌入高密度材料照射的6 MV光子束的字段大小为10 × 10厘米。我们评估了吸收剂量分布与三种不同的技术：叠加算法，辐射变色膜，和注量图Monte Carlo（FMMC）method.Results：与辐射变色膜和FMMC获得的结果是在良好的协议（+/- 5%的剂量）彼此。叠加算法通常被认为比其他市售剂量计算算法更上级，但其结果的准确性明显低于FMMC。特别是，在高密度cerrobend不均匀性的下游，叠加算法预测的剂量比测量值高至少10-16%，这取决于不均匀性的大小和距离。在高密度不均匀性的上游，叠加算法预测的剂量低于测量值，因为它无法预测不均匀性界面附近的剂量增强。高密度不均匀性下游的输送剂量将显著小于由叠加算法计算的处方剂量。基于叠加算法输入注量数据和Monte Carlo的混合的FMMC方法可以是在存在高密度（例如牙科）材料的情况下预测剂量的有用工具。(c)2006爱思唯尔爱尔兰有限公司保留所有权利。
Background and purpose: During radiotherapy planning high density dental materials create a major challenge in determining correct dose distribution inside patients with head-and-neck tumors.Patients and methods: In this work we investigated the absorbed dose distribution inside a solid water((R)) stab phantom with embedded high density material irradiated by a 6 MV photon beam of field size 10 x 10 cm. We evaluated the absorbed dose distribution with three different techniques: superposition algorithm, radiochromic film, and the fluence map Monte Carlo (FMMC) method.Results: The results obtained with radiochromic film and FMMC were in good agreement (within +/- 5% of the dose) with one another. The superposition algorithm, which is often considered superior to other commercially available dose calculation algorithms, produced appreciably less accurate results than FMMC. In particular, downstream from the high density cerrobend inhomogeneity the superposition algorithm predicts a higher dose than the measurement does by at least 10-16% depending upon the size of the inhomogeneity and the distance from it. Upstream of the high density inhomogeneities the superposition algorithm predicts a lower than measured dose due to its failure to predict the dose enhancement close to the inhomogeneity interface.Conclusions: The delivered dose downstream from a high density inhomogeneity would be significantly less than the prescribed dose calculated by the superposition algorithm. The FMMC method which is based on a hybrid of the superposition algorithm input fluence data and Monte Carlo can be a useful tool in predicting dose in the presence of high density (e.g. dental) materials. (c) 2006 Elsevier Ireland Ltd. All rights reserved.