基于投影的X射线光栅相衬成像系统的仿真模拟

Numerical simulation of X-ray grating phase contrast imaging system based on projection

基于投影的X射线光栅相衬成像技术由于具有较大的成像视场以及可以实现较高能量的成像,有望实现医学临床应用。由于其光学元件较多,在系统设计时确定合适的结构参数是一件复杂而艰难的工作。因此,通过一定的合理假设,构建系统的计算机数值仿真模型,利用计算机强大的循环计算能力,实现相关参数对系统性能影响的分析进而实现参数优化将是一个很好的选择。根据基于投影的X射线光栅相衬成像装置的结构原理,同时将成像系统抽象为一个线性系统,在此基础上构建出成像系统的数学模型。并将其转变为适合于计算机的离散模型,实现基于投影的X射线光栅相衬成像的模拟仿真。最后,利用国家同步辐射实验室相衬平台采集的数据验证了该模拟方法的正确性。

With the larger view and higher imaging energy, the technology of X-ray grating phase contrast imaging based on projection is expected to achieve clinical application. However, it was complex and difficult to determine the appropriate structure parameters when the imaging device is designed, because the system contains many optical components. By some reasonable assumptions, a computer numerical simulation model of the system is built, and it is a good choice using the powerful cycle calculation ability of computer to analyze the effect of related parameters on system performance and realize the parameters optimization. Herein, the imaging system was abstracted as a linear system, and base on that, a mathematical model was built according to the principle the X-ray grating phase contrast imaging system. And then, the mathematical model was turned into a discrete model which was suitable for computer, realizing the simulation of X-ray grating phase contrast imaging system based on projection. Finally, the correctness of the simulation was verified using the experimental data acquired from the phase contrast platform at the National Synchrotron Radiation Laboratory.