Simplified derivation of stopping power ratio in the human body from dual-energy CT data
Simplified derivation of stopping power ratio in the human body from dual-energy CT data
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DOI：
10.1002/mp.12386
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发表时间：
2017-08-01
期刊：
影响因子：
3.8
通讯作者：
Sagara, Shota
中科院分区：
文献类型：
--
作者：
Saito, Masatoshi;Sagara, Shota
目的：本研究的主要目的是为人体组织的平均激发能（I值）和有效原子序数（Z（eff））之间的经验关系提出一种替代的参数化方法，并给出一个简化的公式（我们称之为DEEDZ-SPR），用于通过电子密度（rho（e））和Zeff校准从双能（DE）CT数据导出阻止功率比（SPR）。我们对ICRU报告46的人体等效组织（作为SPR和rho（e）未知的感兴趣对象）的DEEDZ-SPR方法进行了数值分析。使用XCOM光子截面数据库计算这些材料的衰减系数。我们还应用DEEDZ-SPR转换到文献中的实验DECT数据，这是测量的组织表征幻影使用双源CT扫描仪在80 kV和140 kV/Sn。结果：结果发现，DEEDZ-SPR转换使SPR的计算简单地通过加权减法的电子密度图像和低或高kV的CT图像。在SPR范围从0.258（肺）到3.638（骨矿物-羟基磷灰石）内，模拟SPR与参考值非常一致。所有ICRU-46人体组织与参考SPR的相对偏差均在+/- 0.6%范围内，甲状腺除外，其偏差为-1.1%。总均方根误差为0.21%。应用实验DECT数据证实了这一协议内的实验精度，这表明了实际可行性的method.Conclusions：DEEDZ-SPR转换方法可以方便SPR图像的建设，准确地作为最近的DECT为基础的SPR参数化的校准程序直接基于CT数的DECT数据集。(C)2017年美国医学物理学家协会
Purpose: The main objective of this study is to propose an alternative parameterization for the empirical relation between mean excitation energies (I-value) and effective atomic numbers (Z(eff)) of human tissues, and to present a simplified formulation (which we called DEEDZ-SPR) for deriving the stopping power ratio (SPR) from dual-energy (DE) CT data via electron density (rho(e)) and Zeff calibration.Methods: We performed a numerical analysis of this DEEDZ-SPR method for the human-body-equivalent tissues of ICRU Report 46, as objects of interest with unknown SPR and rho(e). The attenuation coefficients of these materials were calculated using the XCOM photon cross-sections database. We also applied the DEEDZ-SPR conversion to experimental DECT data available in the literature, which was measured for the tissue-characterization phantom using a dual-source CT scanner at 80 kV and 140 kV/Sn.Results: It was found that the DEEDZ-SPR conversion enables the calculation of SPR simply by means of the weighted subtraction of an electron-density image and a low-or high-kV CT image. The simulated SPRs were in excellent agreement with the reference values over the SPR range from 0.258 (lung) to 3.638 (bone mineral-hydroxyapatite). The relative deviations from the reference SPR were within +/- 0.6% for all ICRU-46 human tissues, except for the thyroid that presented a -1.1% deviation. The overall root-mean-square error was 0.21%. Application to experimental DECT data confirmed this agreement within the experimental accuracy, which demonstrates the practical feasibility of the method.Conclusions: The DEEDZ-SPR conversion method could facilitate the construction of SPR images as accurately as a recent DECT-based calibration procedure of SPR parameterization based directly on the CT numbers in a DECT data set. (C) 2017 American Association of Physicists in Medicine