免分析光栅一次曝光相位衬度成像方法

X射线光栅微分相位衬度成像技术可以观察到常规吸收衬度成像难以分辨的弱吸收物质的精细结构信息,因而在医学、材料学等研究领域具有巨大的应用前景.但传统的X射线光栅微分相位衬度成像技术由于采用分析光栅作为空间滤波器,需要采用相位步进法扫描分析光栅来获得样品的多张投影图像才能够分离出样品的吸收、折射和散射信息,因此存在样品曝光...

Method of single exposure phase contrast imaging without analyser grating

X-ray differential phase contrast imaging technology can reveal the weakly absorbing fine structure which cannot be observed by the conventional X-ray absorption contrast imaging.Hence,it has potential applications in many fields such as medical science,and material science.But in the traditional X-ray grating differential phase contrast imaging system,the analyser grating is used as a spatial filter,and needs to be phase stepped,then multiple exposures are required for information extraction.Thus this leads to high-dose radiation exposure and low efficiency of X-ray utilization.All these disadvantages limit its application in various disciplines.In order to cope with the above issues,a new algorithm based on single-shot grating differential phase contrast imaging system without analyzer grating is proposed.In such a system the absorption,refraction and scattering information can be obtained from one projective image of the sample acquired by a high-resolution detector.The reliability of this new algorithm is confirmed by numerical simulation.Compared with the phase stepping algorithm,the proposed algorithm can provide very accurate and reliable information extraction results without requiring the grating period to match with detector pixel size.It facilitates the reduction of the radiation damage to sample.We emphasize that this method is highly compatible with the future X-ray phase contrast imaging clinical applications.