Eccentric figure-eight magnetic stimulator coils

Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive treatment for neurological and psychiatric diseases. We proposed an eccentric figure-eight coil which induces strong eddy currents in the target tissue at lower driving currents. In this study, numerical analyses were carried out to obtain magnetic field distribution of the eccentric figure-eight coil, eddy current distribution in the brain, and circuit characteristics. The analyses were performed with varied design parameters to show the influence of these parameters on coil characteristics. A prototype eccentric coil and driving circuit were fabricated. The coil generated a magnetic field of 1.7 T at the maximum output level of stimulator.