Multichannel system for measuring the magnetic flux density generated by tms devices

Abstract

Transcranial magnetic stimulation (TMS) is a noninvasive technique that promotes the neuromodulation effect aiming at treating diseases of neuro-psychiatric origin. TMS electromagnetic coils provide an alternating magnetic field that induces bioelectric currents in a targeted region of the brain tissue. The guarantee of treatment effectiveness and safety of both patients and device operators depends on the distribution of the magnetic flux density emitted in the vicinity of the TMS equipment, according to the design of the induction coil employed. This work presents the development of a multichannel measuring system to evaluate the configuration of magnetic flux density generated in the proximities of TMS devices. By using the developed measuring system, it is performed the magnetic mapping along a plane under the figure-of-eight TMS coils, including the study of its response to different intensities and distances from the device. The results allow characterizing the decay of field magnitude towards the region closer to the operator’s hand position and its spatial distribution in areas intended to receive the therapeutic effect.