用于经颅磁刺激预测量的三维磁场传感器阵列设计

Design of 3-D Magnetic Field Sensor Array for Transcranial Magnetic Stimulation Pre-testing

目的基于电磁感应原理,提出一种三维磁场传感器阵列,用于评估经颅磁刺激(TMS)线圈产生的磁场分布。方法将大脑简化为4层的长方体结构,每层放置24、24、20、20个传感器,以此设计三维磁场传感器阵列的结构,并根据法拉第电磁感应定律标定传感器系数。验证三维磁场传感器的精确度和稳定性,并对由88个三维传感器组成的阵列结构实施测试。结果三维磁场传感器测量精度为0.99%;间隔10个月进行4次测量,后3次测量结果与第一次测量结果的相对误差均在0.5%以下,且三维磁场传感器阵列能够准确测出空间磁场的分布情况。88个点的测量结果与有限元分析结果的相对误差平均值约为1%。结论本文设计的三维磁场传感器阵列为评估TMS线圈磁场分布提供了一种切实可行的新方法,有助于提高TMS的安全性。

Objective To evaluate the magnetic field distribution generated by transcranial magnetic stimulation(TMS)coils,a three-dimensional(3-D)magnetic field sensor array based on the principle of electromagnetic induction was proposed.Methods The brain was simplified to a cuboid structure of four layers,with 24,24,20 and 20 sensors in each layer.The structure of 3-D magnetic field sensor array was designed,and the sensor coefficients were calibrated according to Faraday's law of electromagnetic induction.Then the accuracy and stability of the 3-D magnetic field sensor was verified,and the array structure composed of 88 three-dimensional sensors was tested by the designed experiments.Results The measurement accuracy of the 3-D magnetic field sensor was 0.99%.Four measurements were made in ten months,and the relative errors calculated by the last three measurements and the first measurement were below 0.5%.At the same time,the 3-D magnetic field sensor array could accurately measure the distribution of the spatial magnetic field.The relative errors between the measured results of 88 points and the results of finite element analysis were solved,and the average value of 88 relative errors was about 1%.Conclusion The implementation of the 3-D magnetic field sensor array provides a practical and feasible method for evaluating the magnetic field distribution of the TMS coil,and it is helpful to improve the safety of the TMS.