Jiang Xiaolei, Zhang Li, Zhang Ran, Yin Hongxia, Wang Zhenchang
Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084, China ; Department of Engineering Physics, Tsinghua University, Beijing 100084, China.
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China.
Comput Math Methods Med. 2015;2015:623236. doi: 10.1155/2015/623236. Epub 2015 May 18.
X-ray grating interferometry offers a novel framework for the study of weakly absorbing samples. Three kinds of information, that is, the attenuation, differential phase contrast (DPC), and dark-field images, can be obtained after a single scanning, providing additional and complementary information to the conventional attenuation image. Phase shifts of X-rays are measured by the DPC method; hence, DPC-CT reconstructs refraction indexes rather than attenuation coefficients. In this work, we propose an explicit filtering based low-dose differential phase reconstruction algorithm, which enables reconstruction from reduced scanning without artifacts. The algorithm adopts a differential algebraic reconstruction technique (DART) with the explicit filtering based sparse regularization rather than the commonly used total variation (TV) method. Both the numerical simulation and the biological sample experiment demonstrate the feasibility of the proposed algorithm.
X射线光栅干涉测量法为研究弱吸收样品提供了一个新的框架。单次扫描后可获得三种信息，即衰减、微分相衬（DPC）和暗场图像，为传统的衰减图像提供了额外的补充信息。通过DPC方法测量X射线的相移；因此，DPC-CT重建的是折射率而非衰减系数。在这项工作中，我们提出了一种基于显式滤波的低剂量微分相重建算法，该算法能够在减少扫描次数的情况下进行重建且无伪影。该算法采用基于显式滤波的稀疏正则化的微分代数重建技术（DART），而非常用的总变差（TV）方法。数值模拟和生物样品实验均证明了该算法的可行性。
