Multicontrast x-ray computed tomography imaging using Talbot-Lau interferometry without phase stepping
Multicontrast x-ray computed tomography imaging using Talbot-Lau interferometry without phase stepping
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DOI：
10.1118/1.3672163
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发表时间：
2012-01-01
期刊：
影响因子：
3.8
通讯作者：
Chen, Guang-Hong
中科院分区：
文献类型：
--
作者：
Bevins, Nicholas;Zambelli, Joseph;Chen, Guang-Hong
目的：这项工作的目的是证明多对比度计算机断层扫描（CT）成像可以使用Talbot-Lau干涉仪进行无相位步进，从而允许像用于标准吸收CT的采集方案。不是使用相位步进来提取折射、小角散射（SAS）和吸收信号，稍微旋转Talbot-Lau干涉仪的两个光栅以在检测器上产生莫尔锐图案。进行莫尔锐斑图案的傅立叶分析以获得三个对比度信号中的每一个的单独投影图像，所有这些都来自相同的单次X射线曝光。从所有视角的探测器数据中提取信号后，进行图像重建以获得吸收、折射和SAS CT图像。扫描物理体模以验证所提出的数据采集方法。使用标准的相位步进approach.Results的幻影扫描的结果进行了比较：每个对比机制的重建产生预期的结果。信号电平和对比度匹配使用相位步进technique.Conclusions：吸收，折射，SAS CT成像可以实现使用Talbot-Lau干涉仪，而无需额外的开销长扫描时间和相位步进。(C)2012年美国医学物理学家协会。[DOI 10.1118/1.3672163]
Purpose: The purpose of this work is to demonstrate that multicontrast computed tomography (CT) imaging can be performed using a Talbot-Lau interferometer without phase stepping, thus allowing for an acquisition scheme like that used for standard absorption CT.Methods: Rather than using phase stepping to extract refraction, small-angle scattering (SAS), and absorption signals, the two gratings of a Talbot-Lau interferometer were rotated slightly to generate a moireacute pattern on the detector. A Fourier analysis of the moireacute pattern was performed to obtain separate projection images of each of the three contrast signals, all from the same single-shot of x-ray exposure. After the signals were extracted from the detector data for all view angles, image reconstruction was performed to obtain absorption, refraction, and SAS CT images. A physical phantom was scanned to validate the proposed data acquisition method. The results were compared with a phantom scan using the standard phase stepping approach.Results: The reconstruction of each contrast mechanism produced the expected results. Signal levels and contrasts match those obtained using the phase stepping technique.Conclusions: Absorption, refraction, and SAS CT imaging can be achieved using the Talbot-Lau interferometer without the additional overhead of long scan time and phase stepping. (C) 2012 American Association of Physicists in Medicine. [DOI: 10.1118/1.3672163]