Research On Realistic Head Finite Element Modeling Based On Medical Image For TMS Application

Transcranial magnetic stimulation (TMS) has got more and more attention in cranial nerve and brain functioning fields in recent decades. TMS is widely favored by researchers and clinical workers due to its advantages of non-invasiveness and painlessness. Developing a realistic human head finite element model (FEM) is one of the critical steps in TMS simulation and premises researches in electromagnetic field and energy field distribution in TMS application.Firstly deep analysis on human head physiological structure was performed, and with TMS simulation application for purpose, a seven-part realistic human head model, scalp, skull, CSF, grey matter, white matter, cerebellum and eyes included, was proposed. The seven parts were separately derived and then reconstructed into3D model from a set of MRI images by using MIMICS and combining a series of medical image segmentation methods. Comparing to five-shell head model, this seven-part model was closer to realistic human head. On this basis, setting up corresponding finite element meshing principles and standards, combined with the actual needs of TMS application, remeshing and optimizing over the realistic human head model mentioned above was performed by using the FEM remeshing software3-matic and eventually a realistic human head finite element model for TMS application was established.TMS is mainly applied in brain science and clinical researches, thus it is of significantly importance to accurately measure the magnetic field strength in real-time. Furthermore, its effect on human body should be taken into consideration. Hence, a high-frequency weak magnetic field strength measurement and calibration method was studied in this paper. A device for magnetic field calibration was designed to achieve precise control over experimental condition and Experiments were carried out based on it. The results showed that under good stability and consistency, measurement results kept good agreement with true value estimated, accurate measurement of magnetic-field strength can be achieved.