X射线衍射增强成像中吸收、折射以及散射衬度的计算层析

Absorption,Refraction and Extinction Contrast Computerized Tomography of X-Ray Diffraction Enhanced Imaging Method

X射线相位衬度成像是一种新型的X射线成像技术,通过记录射线穿过物体后相位的改变对物体进行成像,可以提供比传统的X射线吸收成像更高的图像衬度以及空间分辨力。衍射增强成像方法(Diffraction enhancedimaging,DEI)是X射线相位衬度成像方法之一,利用一块放置在物体和探测器之间的分析晶体提取物体的吸收、折射以及散射信息并进行成像。将衍射增强成像方法与计算机断层成像技术(Computerized Tomography)进行结合,利用吸收、散射以及折射信息,分别采用滤波反投影以及雷登(Radon)变换,对昆虫样品——蜜蜂进行计算层析重建,获得了好于X射线吸收计算层析的重建结果,验证了衍射增强成像信息分离计算层析的优越性。

The X-ray phase-contrast imaging method, which images the object by recording the phase change after X-ray passing through the object, is a new X-ray imaging technique. This new imaging method can provide higher contrast and spatial resolution than the conventional X-ray absorption imaging method. Diffraction enhanced imaging （DEI） method is one of the four phase-contrast X-ray imaging techniques. DEI method can extract the absorption, refraction and extinction information of the object with an analyzer crystal placed between the object and detector. DEI method is combined with the computed tomography （CT）, EDI-CT, to construct the insect sample a bee with its absorption, extinction and refraction information with filtered back algorithm and Radon transform method. The results obtained by DEI-CT are better than the absorption CT, and proves that the DEI-CT is superior to the conventional CT.