针孔X射线荧光CT探测角度优化研究  

Optimization of Detection Angle for Pinhole X-Ray Fluorescence Computed Tomography

作　　者：郭静 冯鹏[1,2] 邓露珍 罗燕 何鹏[1,2] 魏彪[1,2] Guo Jing;Feng Peng;Deng Luzhen;Luo Yan;He Peng;Wei Biao(Key Laboratory of Optoelectronics Technology&System,Ministry of Education,Chongqing University,Chongqing 400044,China;Industrial CT Non-destructive Testing Engineering Research Center,Ministry of Education,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学光电技术及系统教育部重点实验室,重庆400044 [2]重庆大学工业CT无损检测教育部工程研究中心,重庆400044

出　　处：《光学学报》2020年第1期237-245,共9页Acta Optica Sinica

基　　金：国家重点研发计划(2019YFC0605203);国家自然科学基金(11605017);中央高校基金基本科研业务费项目(2019CDYGYB019);重庆市教委科学技术研究计划(KJQN201904007);工信部“绿色制造系统集成”专项(2018ZZCQ105)。

摘　　要：在管激发X射线荧光CT(XFCT)成像研究中,探测角度与系统背景噪声、探测灵敏度、信噪比等参数密切相关。鉴于此,基于Geant4设计一套多针孔准直管激发XFCT成像系统,并对探测角度与成像系统信噪比、重建图像质量之间的关系进行研究。通过改变管电压、金纳米溶液质量分数、感兴趣区域直径三个参数,模拟60°、90°、120°和150°等不同探测角度下的X射线荧光投影数据和散射噪声的探测过程,并计算其信噪比。仿真结果表明:探测角度的增大能够提升信噪比和重建图像质量,多数情况下,探测角度为120°时的信噪比最佳。Detection angle is closely related to background noise,detection sensitivity,signal-to-noise ratio,and other parameters in the study of tube-excited X-ray fluorescence computed tomography(XFCT)imaging.Accordingly,we simulate a polychromatic tube-excited XFCT imaging system with multi-pinhole collimator using Geant4 to investigate the effect of detection angle on the signal-to-noise ratio and the reconstructed image quality.By changing the tube voltage,mass fraction of gold nanometer solution,and diameter of the region of interest,the signal-to-noise ratio is calculated by simulating the detection processes of the X-ray fluorescence projection data and scattering noise at four angles:60°,90°,120°,and 150°.The simulation results reveal that the signal-to-noise ratio and reconstructed image quality could be effectively improved by increasing the detection angle.For most circumstances,the highest signal-to-noise ratio could be obtained when the detection angle is set to 120°.

关 键 词：成像系统 X射线荧光CT 康普顿散射 探测角度 信噪比 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]