【作者】 王勇；

【导师】 杨永辉； 李正国；

【作者基本信息】 辽宁科技大学 ， 电子信息， 2024， 硕士

【摘要】 经颅磁刺激(Transcranial Magnetic Stimulation,TMS)是一种用于治疗各种神经系统疾病的非入侵性神经调节技术。刺激线圈作为经颅磁刺激系统的关键部件之一,其产生感应电场作用于大脑神经元,进而影响神经元上动作电位的传递。为了提高刺激线圈的聚焦性能,减少非目标区域的不良影响,本文基于电磁场的基本原理设计了两款新型的TMS线圈,并分别进行物理参数优化;同时,为了更加精准地评价线圈的聚焦性能,在原有的评价体系上增加了两个真实反应电场聚焦度的评价指标,使得线圈产生的感应电场的评价更加真实客观。其主要研究内容如下:首先,针对现有的TMS线圈评价体系对聚焦性能不准确不完善的问题,进行了补充,提出了两个能够有效地反映大脑模型中不同高度切面的感应电场的评价参数:有效面积占比和半宽度距离。二者能够直观地显示电场的聚焦情况,为线圈刺激效果分析提供便利。其次,为了提高刺激线圈的聚焦性能,本文通过改变线圈的几何结构设计了两款新型折叠线圈:对点双锥形线圈(Double Conical Coil for Opposite Points,DCCOP)和偏心折叠线圈(Eccentric Folding Coil,EFC)。利用人体组织三维医学电磁仿真软件Sim4Life和PHM库中受试者的脑模型进行有限元仿真分析,对EFC的几何结构的折叠距离和折叠角度进行单目标的优化,以及选用粒子群算法对DCCOP线圈上下两层的夹角进行多目标的参数优化。有限元模拟结果表明,EFC和DCCOP线圈都是高聚焦性能的刺激线圈,且DCCOP线圈在刺激深度上也有较好的表现。最后,对可控磁刺激电路进行分析与设计,搭建实物测试平台测试8字形线圈、EFC和DCCOP线圈产生的磁场分布情况,实验结果表明,改进后的线圈能够有效提高模型所受磁场的聚焦度,具有一定的实用价值。更多还原

【Abstract】 Transcranial Magnetic Stimulation(TMS)is a noninvasive neuromodulation technique for treating various neurological disorders.The stimulation coil,as one of the key components of the TMS system,generates an induced electric field that acts on the brain neurons,thereby affecting the transmission of action potentials on the neurons.In order to evaluate the focusing performance of the coil more accurately,this thesis adds two new evaluation indicators that reflect the real response of the electric field focusing degree on the existing evaluation system,making the evaluation of the induced electric field generated by the coil more realistic and objective.In order to improve the focusing performance of the stimulation coil and reduce the adverse effects of the non-target area,this thesis designs two new types of TMS coils based on the basic principles of electromagnetic fields.The main research contents are as follows:First,aiming at the problem that the existing TMS coil evaluation system is inaccurate and incomplete for the focusing performance,it is supplemented and designed two evaluation parameters that can effectively reflect the effective stimulation distribution of different height sections in the brain model and have practical significance:effective stimulus area ratio(ESAR)and half-width region(HWR).They can intuitively show the focusing situation of the electric field and provide convenience for the analysis of the coil stimulation effect.Second,in order to improve the focusing performance of the stimulation coil,this thesis designs two new types of folding coils by changing the geometric structure of the coil:double conical coil for opposite points(DCCOP)and eccentric folding coil(EFC).The finite element simulation analysis is carried out using the human tissue three-dimensional medical electromagnetic simulation software Sim4Life and the brain model of the subject in the PHM library.The geometric structure of EFC:folding distance and folding angle are optimized for single target,and the particle swarm algorithm is used to optimize the angle of the upper and lower layers of DCCOP coil for multi-target.The finite element simulation results show that EFC and DCCOP coils are both high focusing stimulation coils,and DCCOP coils also exhibit good performance in stimulation depth.Finally,the controllable magnetic stimulation circuit is analyzed and designed,and the physical test platform is built to test the magnetic field distribution of the figure-eight coil,EFC coil and DCCOP coil.The experimental results show that the improved coil can effectively reduce the focusing degree of the magnetic field received by the model,which has certain practical value.更多还原