小动物CT-SPECT双模态成像系统中CT几何畸变校正方法  

CT geometrical deformation calibration method in animal dual-modality CT-SPECT system

作　　者：季栖凡[1] 李军[1,2] 曹文田 包尚联[1] 

机构地区：[1]北京大学医学物理和工程北京市重点实验室,北京100871 [2]北京大学实验动物中心,北京100871

出　　处：《中国医学影像技术》2010年第11期2179-2183,共5页Chinese Journal of Medical Imaging Technology

基　　金：国家重点基础研究发展计划(973计划)项目(2006CB705705);国家自然科学基金(60672104);北京市共建项目(JD100010607)

摘　　要：目的在北京大学医学物理和工程实验室研发的一个基于平板探测器的锥形束X线计算机断层扫描成像装置和单光子发射计算机断层扫描成像组成的双模态小动物成像系统中,提出一种用于校正机械系统不完善所引起的CT图像几何畸变的新方法。方法为系统建立一个笛卡尔坐标系,用鲍威尔算法对几何畸变参数进行计算。结果选取以平板探测器中心为坐标原点的坐标系统,所有几何参数均在该系统中进行定义,相应的几何畸变参数得到精确计算,基本上消除了几何伪影,经过校正后的重建图像质量有较大改善。结论该方法可有效校正小动物CT-SPECT双模态成像系统中CT图像的几何畸变,也适用于其他锥形束计算机断层扫描成像装置,并可作为单光子发射计算机断层扫描成像装置的几何畸变校正和双模态图像配准的基础。Objective To propose a new method,in order to correct the geometrical deformation existed in mechanism system in a flat-panel detector based on cone beam CT and pinhole SPECT assembled dual modality small animal CT-SPECT system developed in our laboratory.Methods A Cartesian coordinate system was defined for the dual modality small animal imaging system,the Powell algorithm was used to address the geometrical parameters.Results In the Cartesian coordinate system,origin was fixed on the center of flat-panel detector,and all geometrical parameters were defined and calculated.After the corrections,geometrical artifacts were removed effectively,and the quality of the image was greatly improved.Conclusion This method can accurately correct the geometrical deformations in dual modality small animal CT-SPECT system.This approach is also applicable to other cone-beam X-ray computed tomography imaging system,and it is also a solid base for SPECT geometrical correction,as well as the image registration between CT and SPECT images.

关 键 词：体层摄影术 发射型计算机 单光子 体层摄影术 X线计算机 平板探测器 

分 类 号：R814.2[医药卫生—影像医学与核医学] R-332[医药卫生—放射医学]