A Parallel 3-D impedance method to compute the Induce Current in Human Head by TMS

The induced current density distribution in human head model caused by transcranial magnetic stimulation (TMS) is simulated based on the parallel 3-dimenstional impedance method. The magnetic field from a typical TMS coil which is placed at the surface of human head, for present the clinically of depression treatment, is calculated by Biot-Savart law. The parallel 3-D method is implemented on an 8-CPU computer cluster. The distribution of induced current density is simulated and the results show the higher conductivity tissues such as blood, cerebral spinal fluid, muscle, and ligament have higher currents in the skull. The maximum induced current density in the head model is 180 A/m² corresponding to the magnitude 10000 A for rTMS protocol. The results show biological interesting for further TMS study.