Simulation proposal of a transcranial focused magnetic stimulation system

Transcranial magnetic stimulation research has yielded promising results with the aim of finding a treatment for motor defects with no adverse effects, so it is important to design safe and economical prototypes to contribute to the study of these conditions. This work presents the development of a simulation of a system for the generation of focused magnetic fields by means of a figure-8 coil using the finite element method. Due to the geometry of the 8-shaped coils and based on the principle of magnetic superposition, it is possible to control the depth and area of stimulation. The characteristics of the coil considering the simulations cover frequencies from 1 Hz to 5 Hz, a maximum magnetic induction of 2 T and a current of 3.6 kA from the discharge of a capacitor with a time of 10 ms were considered as initial conditions of the model., an environmental temperature of 25°C and an absolute pressure of 0.77 atm corresponding to Mexico City, a relative permeability and permittivity of the copper conductor of 1 H/m and F/m respectively, in the same way, these values were taken for the air, adding an electrical conductivity of 0 S/m and for the simulation of the human head, the electrical properties of the skull, brain, scalp and cerebrospinal fluid were considered. The resulting dimensions of the coil, from the simulations, were 6 cm outer radius, 150 turns of each turn with a total of 8 turns, 4 distributed on each wing and a height of 5.5 cm.