Whole-body Electromagnetic Model And Its Preliminary Application In Electromagnetic Field Biological Effect Research

This paper introduced the progress of bioelectromagnetics briefly, analyzed the biological effects mechanism, such as peripheral nerve and cardiac stimulated by the induced currents of transient magnetic fields in a MRI scan. It was shown that the whole-body electromagnetic model is an important tool in bioelectromagnetic field biological effect research.Based on the finite differential time domain (FDTD) method and the real electromagnetic characteristic parameters, the software package of the whole-body electromagnetic model was constructed. A three-dimensional numerical electromagnetic model which is suitable for FDTD method calculation in grids space was also set up. It realized the graphic display of the equal-permittivity and the equal-conductivity curves at any section of human body. As absorption boundary conditions are critical in the FDTD method, several typical absorption boundary conditions were simulated and compared considering the computer speed and memory. The results showed that the perfect matching layer (PML) method is more effective than the others.The biological effect of MRI longitudinal gradient coils was also simulated. Combining the whole-body electromagnetic model and the Maxwell pair coils, the induced-current distribution in human body was computed. The results showed that the peak-induced current is very close to the cardiac stimulation threshold. So we suggested that the induced current should act as an important role in MRI gradient coil design in the future.In the last chapter of this paper, several remarks of this study were discussed. Considering saving the computer memory and increasing the calculation speed, the Pseudospectral time-domain (PSTD) numerical method is more effective than the FDTD method. In addition, the parallel computing technique is necessary in such eletromagnetic field biological effect simulation research.