Numerical Simulation Research Of X-ray Grating-based Phase

X-ray phase contrast imaging is an emerging research field in the X-ray imaging.On the one hand it can obtain refraction,scattering and absorption information of the object in one imaging process.Thus,it can provide the internal information of the object which could not be reflected by traditional absorption contrast imaging.On the other hand,the phase contrast imaging can theoretically obtain higher quality images than conventional absorption contrast imaging for the substances composed of light elements,such as soft tissue of the human body.Through the efforts of researchers in recent decades,several imaging technologies realizing X-ray phase contrast imaging has been proposed.Among them,the grating-based phase contrast imaging method is currently considered the closest clinical application of the X-ray phase contrast imaging technology.The analysis and optimization of the structural parameters of the X-ray grating phase contrast imaging system is one of the most important research work in the system designed.It is also an unavoidable pre-work for other related research which relied on the application of X-ray grating phase contrast imaging.However,because the imaging system with many optical components,it is a complex and difficult work to determine the appropriate structural parameters relying on theoretical analysis in the system design.In this paper,at first,basing on some reasonable assumptions and abstractions,we construct the mathematical model of the grating phase contrast imaging system using the linear system theory and the scalar diffraction theory.Then the computer numerical simulation model of the grating phase contrast imaging system is established by using Matlab scientific computing language,and verified by the experimental data.The numerical model can realize the flexible and continuous adjustment of each parameter,and can quickly and easily evaluate the influence of a certain parameter on the performance of the system,and then realize the parameter analysis and optimization.At the end of this paper,the numerical simulation model is used to analyze and optimize the parameters of gratings in the imaging system,and an experimental method is proposed to detect the defects of grating structure conveniently and quickly by using the device of the imaging system itself.