基于永磁体和线圈复合结构的磁性粒子成像零磁场研究  

Research on Magnetic Particle Imaging Zero Magnetic Field Based on Permanent Magnet and Coil Composite Structure

作　　者：杨丹[1,2] 刘素羽 张昊[1,2] 李天兆[1,2] 徐彬 Yang Dan;Liu Suyu;Zhang Hao;Li Tianzhao;Xu Bin(College of Information Science and Engineering Northeastern University,Shenyang 110819,China;Ministry of Education Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University,Shenyang 110819,China;School of Computer Science and Engineering Northeastern University,Shenyang 110169,China)

机构地区：[1]东北大学信息科学与工程学院,沈阳110819 [2]东北大学智能工业数据解析与优化教育部重点实验室,沈阳110819 [3]东北大学计算机科学与工程学院,沈阳110169

出　　处：《电工技术学报》2025年第2期335-345,共11页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金项目(U22A20221,61836011,71790614);教育部中央高校基础科研业务费项目(2020GFZD008);辽宁省自然科学基金项目(2021-MS093,2022-MS-119,2021-BS-054);辽宁省教育厅基础科学研究项目2021(LJKZ0014);111项目(B16009)资助。

摘　　要：磁性粒子成像(MPI)中的磁场拓扑结构及其产生的零磁场能够直接对成像结果的质量造成影响。针对MPI系统的零磁场设计,该文提出一种永磁体与线圈复合的磁场结构。该结构综合永磁体能够直接产生大梯度静磁场的优势及电磁线圈通过控制激励方式精准调控磁场的优势来构造线型零磁场(FFL)。对所设计的磁场拓扑结构首先进行了基于圆形线圈、矩形线圈和矩形永磁体所产生静磁场的比较;然后从磁场空间分布、磁场梯度和磁场均匀性等方面对FFL进行分析;最后通过有限元仿真确定了线型零磁场的平移扫描区域范围,并进行了MPI分辨率及血管成像研究。结果表明,该文所提拓扑结构产生的FFL磁场梯度达到3.075 T/m,磁场梯度均匀性达到98.7%,在扫描区域为30 mm×70 mm×70 mm的空间内的成像分辨率能够达到1 mm。证明了该文所提拓扑结构应用于磁性粒子成像系统的可行性。In the magnetic particle imaging(MPI)process,due to different topologies of the selection field and the driving field,significant differences exist in the zero magnetic field region,which has a key influence on the MPI imaging effect.This paper proposes an MPI topology based on the permanent magnet and coil composite structure for large aperture,low power consumption,and high resolution.The feasibility of its application in 3D imaging is verified.The selection magnetic field structure of the MPI device is designed based on the Maxwell configuration.When the excitation current is symmetric,the field-free line(FFL)is distributed along the z-axis;otherwise,the FFL is translated along the x-axis.The driving coil set is designed based on the Helmholtz structure.When the AC excitation signal is input,the driving magnetic field is superimposed with the selection magnetic field,and the FFL is driven to scan along a certain plane perpendicular to the x-axis.Secondly,COMSOL simulation software simulates the magnetic field generated by the composite device,and the effects of current excitation,magnet material,and spatial position on the magnetic field are calculated to determine the maximum scanning range and trajectory of the FFL.Finally,the effects of magnetic field gradient and particle size on the image reconstruction results are analyzed.In the layered scanning simulation,due to the small inter-layer distance,the coupling of signals between adjacent layers is considered in the image reconstruction.The simulation results show that the structure produces a linear magnetic field gradient of 3.075 T/m and 3.064 T/m in the x and y directions.The scanning area of the magnetic field reaches 30 mm×70 mm×70 mm,and the magnetic field uniformity in the scanning area reaches more than 98.7%.MPI simulation and reconstruction using 3 T/m,2 T/m,and 1 T/m magnetic field gradients show a positive correlation between the gradient and the imaging quality.Finally,the 3D vascular model is imaged by layers.The minimum structural similarit

关 键 词：磁性粒子成像 永磁体与线圈复合 线型零磁场 磁场梯度 磁场均匀性 

分 类 号：TM153[电气工程—电工理论与新技术]