Density and atomic number measurements with spectral x-ray attenuation method
Density and atomic number measurements with spectral x-ray attenuation method
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DOI：
10.1063/1.1586963
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发表时间：
2003-08-01
影响因子：
3.2
通讯作者：
Stierstorfer, K
中科院分区：
文献类型：
--
作者：
Heismann, BJ;Leppert, J;Stierstorfer, K
X射线衰减测量广泛应用于医疗和工业领域。通常的结果是衰减系数Mu(R)的一维到三维表示。本文提出了用能量分辨x射线方法计算密度Rho(R)和原子序数Z(R)的ROZ投影算法。作为输入数据，该算法使用至少两个测量值Mu(1)、MU2、……具有不同光谱权重的源光谱S(E)和/或探测器灵敏度D(E)。解析地，Rho是Mu(1)-Cmu(2)的函数，c=Const，Z是Mu(1)/Mu(2)的函数。全数值处理得到以S(E)和D(E)为交换参数函数的Rho(Mu(1)，Mu(2))和Z(Mu(1)，Mu(2))。我们用预先定义了Rho和Z的有机样品和一组化学溶液的双能计算机断层扫描测量来测试该方法。结果图像显示Rho和Z是互补信息：密度Rho反映了物体的形态，而原子序数Z=电子数/原子描述了材料的分布。在我们的实验装置中，Z的绝对精度为0.1，Rho的绝对精度为20 mg/cm(3)。ROZ预测可能会为各种科学、工业和医疗应用带来这些类型的定量信息。(C)2003年美国物理研究所。
X-ray attenuation measurements are widely used in medical and industrial applications. The usual results are one- to three-dimensional representations of the attenuation coefficient mu(r). In this paper, we present the rhoZ projection algorithm for obtaining the density rho(r) and atomic number Z(r) with an energy-resolving x-ray method. As input data the algorithm uses at least two measurements mu(1), mu2,... with different spectral weightings of the source spectrum S(E) and/or detector sensitivity D(E). Analytically, rho is a function of mu(1)-cmu(2), c = const, and Z is a function of mu(1)/mu(2). The full numerical treatment yields rho(mu(1), mu(2)) and Z(mu(1), mu(2)) with S(E) and D(E) as commutative parametric functions. We tested the method with dual-energy computed tomography measurements of an organic sample and a set of chemical solutions with predefined rho and Z. The resulting images show rho and Z as complementary information: The density rho reflects the morphology of the objects, whereas the atomic number Z = number of electrons/atom describes the material distribution. For our experimental setup we obtain an absolute precision of 0.1 for Z and 20 mg/cm(3) for rho. The rhoZ projection can potentially lead to these classes of quantitative information for various scientific, industrial, and medical applications. (C) 2003 American Institute of Physics.