摘要
基于X射线管的X射线荧光计算机断层扫描术(CT)受多种因素影响,成像质量不佳,几何参数误差是制约其高质量图像重建的重要因素之一。本文分析成像二维平面模体与探测器相对位置偏移对投影数据的影响,并基于原始投影数据和原始重建图像再投影数据的局部线性关系实现几何偏移参数校正;利用Geant4模拟存在偏移参数的扇束X射线荧光CT系统,使用模拟投影数据验证校正方法。研究结果表明:该方法能计算出相对精确的几何偏移量,有效消除几何参数误差对重建图像的影响,校正后的重建图像信息熵降低,平均梯度和标准差提高,图像质量提升。
X-ray fluorescence computed tomography(CT) based on an X-ray tubes is affected by many factors, which thus results in poor image quality. Geometric parameter error is one of the important factors that restrict its high-quality image reconstruction. In this paper, the influence of the relative position deviation between the two-dimensional planar phantom and the detector on the projection data is analyzed, and the correction of geometric deviation parameters is realized with the local linear relationship between the original projection data and the reprojection data of the original reconstructed image. Geant4 is employed to simulate the fan-beam X-ray fluorescence CT system with deviation parameters, and simulated projection data are used to verify the correction method. The results show that the method can accurately calculate the geometric offset to a large extent and effectively eliminate the influence of geometric parameter error on the reconstructed image. Regarding the reconstructed image after correction, the information entropy is reduced and the average gradient and standard deviation are enhanced, with the image quality thus improved.
作者
蒋上海
马致臻
罗彬彬
赵明富
汤斌
石胜辉
吴德操
邹雪
龙邹荣
周密
Jiang Shanghai;Ma Zhizhen;Luo Binbin;Zhao Mingfu;Tang Bin;Shi Shenghui;Wu Decao;Zou Xue;Long Zourong;Zhou Mi(Chongqing Key Laboratory of Optical Fiber Sensor and Photoelectric Detection,Chongqing University of Technology,Chongqing 400054,China;College of Science,Chongqing University of Technology,Chongqing 400054,Chi)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2021年第20期46-54,共9页
Acta Optica Sinica
基金
重庆市自然科学基金面上项目(cstc2020jcyj-msxmX0362,cstc2020jcyj-msxmX0879)。
关键词
成像系统
X射线荧光计算机断层扫描术
几何校正
局部线性关系
蒙特卡罗模拟
imaging systems
X-ray fluorescence computed tomography
geometric correction
local linear relationship
Monte Carlo simulation
