A robust method of x-ray source spectrum estimation from transmission measurements: Demonstrated on computer simulated, scatter-free transmission data
A robust method of x-ray source spectrum estimation from transmission measurements: Demonstrated on computer simulated, scatter-free transmission data
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DOI：
10.1063/1.1928312
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发表时间：
2005-06-15
影响因子：
3.2
通讯作者：
Vannier, M
中科院分区：
文献类型：
--
作者：
Sidky, EY;Yu, L;Vannier, M
诊断成像中的x射线谱知识对于剂量计算、束硬化伪影校正和双能计算机断层扫描都很重要。确定x射线源光谱的一种方法是根据已知幻体的传输数据进行估计。虽然这种方法在实验上很简单，但从传输数据中估计频谱是一个已知的病态问题。这项工作的贡献是双重的。首先，我们提出了一种系统的传输测量设计方法，以减少频谱估计的数学不稳定性。其次，我们应用期望最大化（EM）方法，已知该方法可以产生正线性积分方程的鲁棒解，例如描述传输数据的频谱估计的方程。所提出的电磁方法与文献中其他算法的模拟数据进行了比较，从x射线光谱到乳房x线照相术和计算机断层扫描。EM方法似乎优于现有的频谱估计算法。(c) 2005年美国物理研究所。
Knowledge of the x-ray spectrum in diagnostic imaging is important for dose calculations, correction for beam-hardening artifacts, and dual-energy computed tomography. One way to determine the x-ray source spectrum is to estimate it from transmission data of a known phantom. Although such an approach is experimentally simple, spectrum estimation from transmission data is known to be an ill-conditioned problem. The contribution of this work is twofold. First, we present a systematic method of designing the transmission measurements to reduce the mathematical instability of spectrum estimation. Second, we apply the expectation-maximization (EM) method, which is known to yield robust solutions to positive, linear integral equations such as the one that describes spectrum estimation from transmission data. The proposed EM method is compared to other algorithms in the literature on simulated data from x-ray spectra typical to mammography and computed tomography. The EM method appears to outperform existing algorithms for spectrum estimation. (c) 2005 American Institute of Physics.