Wu Xizeng, Liu Hong
Department of Radiology, University of Alabama at Birmingham, Birmingham, Alabama 35233, USA.
Med Phys. 2007 Feb;34(2):737-43. doi: 10.1118/1.2431475.
In this report we clarify two aspects for in-line phase-sensitive x-ray imaging, which includes phase-contrast imaging and phase imaging. First, we point out that there is confusion in the literature about the lateral coherence length, which is widely adopted as the coherence criteria for implementing phase-sensitive imaging. The confusion exaggerates the coherence requirement for clinical implementation of in-line phase-sensitive imaging. Instead we show that the ratio of the phase-space shearing length to lateral coherence length is a good measure for gauging the partial coherence realized in a specific image setting. Second, based on the general intensity equation for in-line phase-sensitive imaging, we discuss the differences between the phase-contrast imaging and phase imaging in terms of the physics mechanism, image acquisition approaches, computation algorithm development, and the potentials for tissue quantitative characterization.
在本报告中，我们阐明了在线相敏X射线成像（包括相衬成像和相位成像）的两个方面。首先，我们指出，文献中关于横向相干长度存在混淆，横向相干长度被广泛用作实现相敏成像的相干标准。这种混淆夸大了在线相敏成像临床应用中的相干性要求。相反，我们表明相空间剪切长度与横向相干长度的比值是衡量特定图像设置中实现的部分相干性的良好指标。其次，基于在线相敏成像的一般强度方程，我们从物理机制、图像采集方法、计算算法开发以及组织定量表征潜力等方面讨论了相衬成像和相位成像之间的差异。
