Determination of EM parameters in human head phantom by transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) has recently founded itself as an endeavoring therapeutic tool as well as a very feasible diagnostic and researching technique of several neurological and psychiatric disorders. The deep transcranial magnetic stimulation may play a vital role in the motivation mechanism. It has become popular because of its noninvasive operation method. In this paper, the numerical simulation for deep transcranial magnetic stimulation (dTMS) has been performed by considering a conventional figure of eight (Fo8) coil operating with the Halo coil [Halo-Fo8 assembly coil (HFA coil)]. The 3D distributions of the electric field, magnetic flux density as well as the current density were numerically calculated by the impedance method. Instead of a realistic head model, a human head phantom was used for the simulation purpose. It was observed for this simulation setup, the HFA coil provides more concentrated magnetic flux density and improved penetration depth in the deep bran regions which is better than that can be achieved from the Fo8 coil operating alone.