| Since the birth of Transcranial Magentic Stimulation(TMS)in the 1980 s,it has been widely used in neurotherapy and rehabilitation because of its non-invasive and painless effects.The problem of poor focus,insufficient stimulation depth and single parameter adjustment of the magnetic stimulation circuit limits the clinical application of the technology to some extent.In this thesis,various structural coils and circuits are studied and analyzed to improve the focus of the induced electric field in the target area,the depth of stimulation and the multi-parameter controllable form of the stimulus.The main research contents are as follows.Firstly,for the focusing performance of the coil structure,the method of changing the shape of the coil is used to simulate and analyze the circular 8-word,the triangle 8-word,the square 8-word,and the pentagon 8-word coil.The results show that the triangular 8-word coil has better focusing,and the circular 8-word coil is the second,and the circular 8-word coil simulation intensity is higher.At the same time,in order to realize the multistructure design of the coil,the circular 8-word coil is selected as the reference coil for analysis.Secondly,for the circular 8-word coil focusing and insufficient stimulation depth,the parameters of the radius,number of turns,winding method and angle of the circular 8-word coil are simulated,and the field distribution in the space is studied.At the same time,the design optimizes the double 8-word coil.Compared with the traditional 8-word coil,the aggregation of the double 8-word coil in the target plane is improved by 20.9%,and the stimulation intensity is increased by 57.8%.Then,based on the double 8-word coil,a coil array is proposed to achieve multi-target stimulation,and the center coil of the array is reoptimized.According to the simulation results,in the target plane,when the two adjacent points are stimulated the focus increased by 15.51% and the stimulation intensity increased by 9.12%.Then,in order to analyze the actual effect of coil stimulation,the real-world head model is combined with the traditional 8-word coil and double 8-word coil to analyze the field distribution of different regions of the head,and the focus and stimulation depth are analyzed.The results show that the double 8-word coil has better stimulation performance.At the same time,in order to improve the design efficiency of coil magnetic stimulation,the visual and friendly interface design of the head and coil joint simulation process is realized,which can realize the convenient setting of parameters such as coil radius,number of turns and current excitation,visually display the simulation results,and analyze the coil stimulation effect.Convenience.Finally,for the single problem of magnetic stimulation waveform,the method of controlling the charge and discharge loop by the microcontroller is used to design the TMS pulse circuit to control the parameters such as the frequency,pulse width and amplitude of the pulse current,and then realize the frequency and pulse width of the magnetic field.And changes in parameters such as amplitude.The results show that the pulse current waveform has a pulse width of 10~100 μs,a frequency of 1~100 Hz and an amplitude of 0.812~4.01 A.In this thesis,through the study of the 8-word coil,and based on the design of the double 8-word coil and array,the stimulation focus and stimulation depth are improved,and the multi-point target region stimulation is realized.At the same time,the pulse generation circuit is designed to realize multi-parameter control of pulse current amplitude,frequency and pulse width,which has certain value in clinical application. |
