八字线圈激励下五层球头模型感应电场能量的分布

Distribution of Induced Electromegnetic Energy with Five-shell Spherical Model Excited by Figure-eight Coils

研究经颅磁刺激(TMS)下人体头部组织内感应电场能量的分布状况,即组织内焦耳热能损耗情况。提出通过感应电能分配率及感应电能集中性两方面因素,研究蚊香型八字线圈激励下头部模型感应电场能量分布情况。利用ANSYS有限元方法建立蚊香型八字线圈,及包含了头皮、头骨、脑脊液、脑灰质和脑白质的五层球头模型,用瞬态分析方法研究感应电场能量分布。仿真结果表明,对线圈施以8 000 A交流电流时,感应电场能量的63.37%消耗于头皮层,其次是脑脊液层上的30.82%,而脑灰质层仅分配了2.6%,而该层能量集中度为15.72%。运用所建立的方法,可为建立逼近于真实条件的头部模型,提高脑神经磁刺激技术聚焦性能和定位性能,提供更加精确的仿真研究结果。

This project is purposed to study the induced electric field energy distribution in human head,which is excited by figure-eight coil used in transcranial magnetic stimulation（TMS）.Spiral figure-eight coils（SFOE） and a five-shell spherical model,including scalp,skull,cerebrospinal fluid（CSF）,grey matter and white matter,were established using ANSYS,and transient analysis on induced electric field energy was conducted.Simulation results showed that,under the exciting current of 8 000 A,63.37% of induced electric field energy was distributed in scalp,30.82% in CSF,and 2.6% in grey matter,while the concentration ratio of induced electric field energy in grey matter was up to 15.72%.The proposed method is expected to improve the accuracy of the stimulation study.