Effect of the different winding methods of coil on electromagnetic field during transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) is a powerful, non-invasive tool for investigating functions in the brain. The target inside the head is stimulated with eddy currents induced in the tissues by the time-varying magnetic field. TMS has been used in several applications in medical and clinical research which include brain mapping, treatment of mood disorder and schizophrenia, treatment of epilepsy, treatment of chronic pain and so on. The stimulation effect can be affected by the stimulation intensity. For coils with the same shape, different winding methods make the coil have different stimulation intensity. In this paper, three different methods for winding circular coils are discussed. The electromagnetic fields induced by the three different circular coils were analyzed. The results show that the circular coil with the pancake coil winding has the strongest stimulation intensity.