提出一种可提高经颅磁刺激8字形线圈聚焦性的方法，即使用高电导率材料制作的窗口挡板减小线圈感应电场聚焦区域面积，并抑制负峰能量，同时采用高磁导率材料制作的导磁体增强线圈感应电场的正峰能量。建立了盐水槽仿真模型，并结合ANSYS有限元仿真，分析窗口板和导磁体对8字线圈感应电场分布的影响。分别使用铜和铁氧体制作了与仿真模型一致的窗口板和导磁体，使用盐水槽和 Magstim Rapid2型磁刺激仪验证了仿真结果。结果表明，结合导磁体比单独使用窗口板具有更好的提高8字形线圈聚焦性能的效果。该方法可以灵活运用到经颅磁刺激线圈实际使用过程中，相比设计新型线圈而言，工作量更少，复杂性更低。%A new method is presented to improve the focalization of figure-of-eight coil ( FOE) , which is usually adopted in transcranial magnetic stimulation ( TMS) .In the method, a highly conductive shield plate with window ( shield) is involved to decrease the focal area of the induced electric field by FOE, while reducing the energy of its negative peaks.Meanwhile, a highly permeable ferromagnetic block ( block) is employed to enhance its positive peak.For this purpose, a realistic saline tank model was es-tablished, based on which finite element simulation studies were carried out via ANSYS, to research the effects of the shield and the block on the distribution of induced electric field of FOE.Besides, a copper shield and a ferrite block were manufactured to further verify the simulation prediction, which were tested with saline tank and Magstim Rapid2 device.Results from simulation and experiment lead to the same conclusion that using shield together with block can guarantee the FOE a better focalization than using the shield alone.This method could be easily used during TMS coil application, and requires less work and involves less complexity than new coil designing.
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