基于迭代重建算法的X射线光栅相位CT成像

发布时间：2018-04-08 21:17

本文选题：X射线光栅成像　切入点：迭代童建算法　出处：《物理学报》2017年05期

【摘要】：基于光栅干涉仪的X射线成像技术可以同时获得样品内部的吸收信息、相位信息和散射信息,既保持了传统X射线衰减成像的优点,又拥有相衬成像和散射成像的优势.然而基于传统CT重建算法的X射线光栅成像需要采集大量完整的原始投影数据,数据采集时间过长从而使得物体接受很大的辐射剂量,难以在实际中应用.提出基于传统代数迭代重建算法的光栅成像技术.该方法利用现有X射线光栅成像系统采集少量原始投影数据,基于传统代数迭代重建算法,对旋转变化的相位数据进行CT重构,同时基于傅里叶变换的方法对微分相位数据进行相位恢复.模拟和实验结果表明,基于少量或不完备的原始投影数据,该方法能够准确重构成像对象的吸收、柑位和散射三维信息,同时还能对微分相位切片进行高信噪比的相位恢复,得到样品折射率实部衰减率,为X射线光栅成像技术在工业、生物和医学诊断等领域的应用提供理论和技术支撑.
[Abstract]:The X-ray imaging technology based on grating interferometer can obtain the absorption information, phase information and scattering information simultaneously, which not only keeps the advantages of traditional X-ray attenuation imaging, but also has the advantages of phase contrast imaging and scattering imaging.However, X-ray grating imaging based on traditional CT reconstruction algorithm needs to collect a large number of complete original projection data, the data acquisition time is too long to make the object accept a large amount of radiation dose, so it is difficult to be applied in practice.A raster imaging technique based on traditional algebraic iterative reconstruction algorithm is proposed.This method uses the existing X-ray grating imaging system to collect a small amount of original projection data, and based on the traditional algebraic iterative reconstruction algorithm, the phase data of rotation change is reconstructed by CT.At the same time, the phase recovery of differential phase data is carried out based on Fourier transform.The simulation and experimental results show that the proposed method can accurately reconstruct the three-dimensional information of absorption, position and scattering of imaging objects based on a few or incomplete original projection data, and can also recover the phase of differential phase slices with high SNR.The real attenuation rate of sample refractive index is obtained, which provides theoretical and technical support for the application of X-ray grating imaging in industrial, biological and medical diagnostics.
【作者单位】：中北大学信息与通信工程学院;中国科学院上海应用物理研究所;
【基金】：国家自然科学基金(批准号:11375257,61301259,U1232205) 中北大学校学科研究基金(批准号:2015110246) 山西省自然科学基金(批准号:2015021099)资助的课题~~
【分类号】：TP391.41;O434.1

【相似文献】