旋转调制器成像的蒙特卡罗仿真及图像重建  

Monte Carlo Simulation and Image Reconstruction of Rotating Modulator Imaging

作　　者：魏星[1] 王锋[1] 王英[1] 肖无云[1] 艾宪芸[1] 徐红鹃[1] 张斌[1] 张磊[1] 

机构地区：[1]防化研究院,北京102205

出　　处：《核电子学与探测技术》2014年第2期184-189,共6页Nuclear Electronics & Detection Technology

基　　金：国民核生化灾害防护国家重点实验室基础研究基金(SKLNBC2013-02)

摘　　要：基于时间调制的旋转调制器(RM)成像技术是一种可以对硬X射线、γ射线等成像的技术。为利用RM成像技术优势,开展了RM技术在核监测领域应用的研究工作。通过蒙特卡罗仿真,模拟准直器旋转过程,布置7个NaI探测器测量,获得受调制的探测器输出,再用NCAR、MLEM和OSEM算法分别对输出数据进行重建。相对NCAR算法,MLEM算法在抑制噪声的同时,不会在重建源图像周围引入随机边缘。OSEM算法可以加速MLEM算法的收敛过程,提高计算速度。MLEM和OSEM重建图像的角度分辨率可达1.2°,与仿真系统几何角度分辨率比较,达到了约3.8倍的超分辨能力。Rotating modulator imaging is a temporal modulating technology which can be used to image hard X -ray,γ-ray,etc.It is now studied for implementation in nuclear monitoring applications .A virtual RM system consisting of 7 NaI detectors is established and its imaging procedure is simulated based on Monte Carlo meth -od.The detector outputs are reconstructed using NCAR ,MLEM and OSEM algorithm respectively .Reconstruc-tion shows that MLEM algorithm can suppress noise as NCAR algorithm without additional random sidelobes . OSEM can improve convergence of MLEM .Reconstructed images of MLEM and OSEM algorithm manifest an angular resolution of 1.2°,which is about 3.8 times better than the geometric resolution .

关 键 词：旋转调制器 蒙特卡罗仿真 图像重建 

分 类 号：TL99[核科学技术—核技术及应用]