Qi Zhihua, Chen Guang-Hong
Department of Medical Physics, University of Wisconsin in Madison, 600 Highland Avenue, Madison, WI 53792-1590, USA.
Phys Med Biol. 2007 Sep 21;52(18):N417-23. doi: 10.1088/0031-9155/52/18/N03. Epub 2007 Sep 4.
Recently, x-ray differential phase contrast computed tomography (DPC-CT) has been experimentally implemented using a conventional source combined with several gratings. Images were reconstructed using a parallel-beam reconstruction formula. However, parallel-beam reconstruction formulae are not directly applicable for a large image object where the parallel-beam approximation fails. In this note, we present a new image reconstruction formula for fan-beam DPC-CT. There are two major features in this algorithm: (1) it enables the reconstruction of a local region of interest (ROI) using data acquired from an angular interval shorter than 180 degrees + fan angle and (2) it still preserves the filtered backprojection structure. Numerical simulations have been conducted to validate the image reconstruction algorithm.
最近，利用传统光源结合多个光栅，通过实验实现了X射线微分相衬计算机断层扫描（DPC-CT）。使用平行束重建公式对图像进行重建。然而，平行束重建公式并不直接适用于平行束近似失效的大图像对象。在本笔记中，我们提出了一种用于扇束DPC-CT的新图像重建公式。该算法有两个主要特点：（1）它能够使用从小于180度+扇角的角度区间采集的数据重建局部感兴趣区域（ROI），（2）它仍然保留了滤波反投影结构。已进行数值模拟以验证该图像重建算法。
