基于Computer Simulation Technology的磁共振射频线圈模拟与设计  

Simulation and design of MRI radiofrequency coil based on computer simulation technology

作　　者：何汶静[1] 许玉霞[1] 黄正宽 HE Wenjing XU Yuxia HUANG Zhengkuan(Medical Image College, North Sichuan Medical College, Nanchong 637000, Chin)

机构地区：[1]川北医学院医学影像学院,四川南充637000

出　　处：《中国医学物理学杂志》2017年第1期44-47,共4页Chinese Journal of Medical Physics

基　　金：川北医学院2015年高等教育教学改革与研究课题;四川省高等教育人才培养质量和教学改革项目(川教函[2014]156号-350)

摘　　要：目的:基于CST(Computer Simulation Technology)软件设计磁共振射频线圈,利用软件功能计算S参数、驻波比,求解每个网格的电场和磁场的方向、大小等,辅助完成实际线圈设计。方法:以单圈线圈为例,设计3层仿真模型:铜箔线圈层、环氧玻璃布层压板层、水模层。正确输入每一层的材料参数,并加入电容、端口等集总参数元件。设计合适的网格划分要求,插入场监视器。结果:数据结果包括一维结果和二、三维结果,其中一维结果包括S参数,驻波比,不连续端口的电流、电压、阻抗,集总参数元件的电流、电压、阻抗等,二、三维结果包括电场分布、磁场分布、表面电流等。从S11参数看出此线圈模型可在21.86 MHz处实现调谐和匹配,实际中可用作0.5 T磁共振成像设备的线圈。电磁场分布结果可以看出电容附近电场强度较高,磁场强度在线圈附近z方向强度较高。结论:磁共振射频线圈的设计可以利用CST软件辅助完成,通过调整线圈的形状、铜箔宽度等建立模型,根据S参数查看调谐匹配、耦合结果,通过场监视器的设置,查看二、三维电磁场分布。由结果再修改模型,最终完成设计。Objective To design a magnetic resonance image（MRI） radiofrequency（RF） coil based on computer simulation technology（CST） software. The CST software function is used to calculate the S- parameter, voltage standing wave ratio（VSWR）, and measure the direction and intensity of electric field and magnetic field of each mesh, assisting the coil design.Methods Taking single RF coil as an example, a simulation model of 3 layers is designed, including copper layer, epoxide woven glass fabric laminated sheet, and water phantom layer. Material parameters of each layer were input correctly, and the lumped elements, such as ports and capacitances, were added. Appropriate mesh control properties were set and the field monitors were inserted. Results The data results include one- dimensional（1D）, two- and three- dimensional（2D/3D） results.The 1D results included S- parameter, VSWR, the current, voltage and impedance of discrete ports, the current, voltage and impedance of lumped elements. The 2D/3D results included electric field distribution, magnetic field distribution, surface current. The 1D simulation result of a single RF coil（S11） parameter indicated that the coil model achieves the tuning and matching at 21.86 MHz, and the coil model was suitable for the 0.5 T MRI device. The results of electromagnetic field distribution showed that the higher the electric field intensity near the capacitance, the higher the magnetic field intensity at the z direction near the coil. Conclusion The design of MRI RF coil can be finished with the assistance of CST software, and the model is established by adjusting the shape of coil and the width of copper foil. Based on the results of the S parameters which show the tuning and matching, and the coupling results and the field monitor which can be used to display the 2D/3D electromagnetic field distribution, the model is modified and completed.

关 键 词：CST软件 磁共振 射频线圈 

分 类 号：TP391.9[自动化与计算机技术—计算机应用技术]