经颅磁刺激8字形线圈聚焦性增强技术仿真研究

Simulation Research on Focusing Enhancement of 8-shaped Coils in Transcranial Magnetic Stimulation

目的分析屏蔽板厚度与窗口形状对8字形经颅磁刺激仪线圈聚焦性的影响,并补偿屏蔽板带来的线圈性能损失。方法通过有限元仿真,对比线圈加上不同厚度和窗口形状的屏蔽板后的感应电流强度、刺激面积等参数。仿真不同形状软磁铁芯对线圈性能的改善。结果屏蔽板厚度取1mm即可起到有效的屏蔽作用,窗口尺寸的选择应以尽量小的矩形包围尽量大的线圈孔内缘长度为原则。加入铁芯可以增强感应电流,并补偿屏蔽板带来的线圈电感减小。结论窗口屏蔽板与铁芯联合使用可以在保证刺激强度和线圈电感值的同时显著提高线圈聚焦性。

Objective To analyze the influence of thickness and window shape of the shield plate on the focusing of the 8-shaped transcranial magnetic stimulator coil,and compensate for the loss of coil performance.Methods The induced current intensity and the stimulation area of coil with the shield plates of different thicknesses and window shapes were simulated with finite element software.The performance improvements with different shape soft magnetic iron-cores were simulated.Results The simulation results showed that 1 mm-thick shield plate could effectively shield unwanted magnetic field.The choice of window size should follow the principle of enclosing the inner edge of the coil as long as possible with the smallest possible rectangular.Adding an iron-core could enhance the induced current and compensate for the reduced coil inductance caused by the shield.Conclusion The combination of the window shield and the iron-core can significantly improve the coil focusing while ensuring the stimulus strength and coil inductance.