Fu Jian, Yu Guangyuan, Fan Dekai
Research Center of Digital Radiation Imaging and Biomedical Imaging, Beijing University of Aeronautics and Astronautics, Beijing 100191, People's Republic of China.
Biomed Mater Eng. 2014;24(6):3105-11. doi: 10.3233/BME-141132.
X-ray phase contrast computed tomography (CT) uses the phase shift that x-rays undergo when passing through matter, rather than their attenuation, as the imaging signal and may provide better image quality in soft-tissue and biomedical materials with low atomic number. Here a geometry-constraint-scan imaging technique for in-line phase contrast micro-CT is reported. It consists of two circular-trajectory scans with x-ray detector at different positions, the phase projection extraction method with the Fresnel free-propagation theory and the filter back-projection reconstruction algorithm. This method removes the contact-detector scan and the pure phase object assumption in classical in-line phase contrast Micro-CT. Consequently it relaxes the experimental conditions and improves the image contrast. This work comprises a numerical study of this technique and its experimental verification using a biomedical composite dataset measured at an x-ray tube source Micro-CT setup. The numerical and experimental results demonstrate the validity of the presented method. It will be of interest for a wide range of in-line phase contrast Micro-CT applications in biology and medicine.
X射线相衬计算机断层扫描（CT）利用X射线穿过物质时发生的相移而非其衰减作为成像信号，在软组织和低原子序数的生物医学材料中可能提供更好的图像质量。本文报道了一种用于在线相衬显微CT的几何约束扫描成像技术。它由在不同位置使用X射线探测器的两次圆形轨迹扫描、基于菲涅耳自由传播理论的相投影提取方法以及滤波反投影重建算法组成。该方法去除了经典在线相衬显微CT中的接触探测器扫描和纯相位物体假设。因此，它放宽了实验条件并提高了图像对比度。这项工作包括对该技术的数值研究以及使用在X射线管源显微CT装置上测量的生物医学复合数据集进行的实验验证。数值和实验结果证明了所提出方法的有效性。它将对生物学和医学中广泛的在线相衬显微CT应用具有重要意义。
