The Establishment And Simulation Of The Head Model Based On TMS

Transcranial magnetic stimulation(TMS)is a green treatment method for neurological diseases and mental disorders.The establishment of head numerical model plays an important role in TMS simulation research.In the previous studies,the head models are simple spherical structure.In fact,there is a big difference between spherical model and real model.In this dissertation,the magnetic resonance imaging(MRI)images are used to reconstruct the head numerical model,which makes the head model more close to the real case.Firstly,a new method of real head model reconstruction is proposed in this thesis.The head tissues segmentation methods mainly include gray threshold segmentation,morphological operation,regional growth,manual editing,and non-manifold assembly.It is more flexible and convenient to establish a more accurate real head model by combining automatic and manual segmentation.The reconstructed model contains four layers of scalp,cerebrospinal fluid,gray matter,and white matter,etc.Secondly,the mesh quality check and correctness verification experiment of the reconstructed head numerical model are carried out.In the static experiment,the relative error of the simulation and theoretical result is allowable,which shows the correctness of establishing model method and finite element analysis(FEA)calculation.Finally,the transient pulse magnetic field experiment is studied for TMS.The distribution of electromagnetic field results of each part of tissues is obtained by FEA calculation.According to the results,in order to meet the requirements of clinical experiment,the stimulation parameters such as coil parameters,source current,and the relative position of the coil and the head,can be adjusted appropriately.The induced current generated by TMS is important in clinical treatment.If there is no pre-testing of the field strength generated by the stimulus coil,it will cause harm to the human body.Therefore,the three-dimensional reconstruction of the TMS real head model and the finite element calculation of the induced electric field and induction current within human brain are of great significance in clinical application.