Computation of electric and magnetic stimulation in XXXX head using the 3-D impedance method.

@entity1 @entity9808 @entity308
A comparative, computational study of the modeling of @entity9808 ( @entity9808 ) and electroconvulsive therapy (ECT) is presented using a @entity1 head model. The magnetic fields from a typical @entity9808 coil of figure-eight type is modeled using the Biot-Savart law. The @entity9808 coil is placed in a position used clinically for treatment of @entity308 . Induced current densities and electric field distributions are calculated in the model using the impedance method. The calculations are made using driving currents and wave forms typical in the clinical setting. The obtained results are compared and contrasted with the corresponding ECT results. In the ECT case, a uniform current density is injected on one side of the head and extracted from the equal area on the opposite side of the head. The area of the injected currents corresponds to the electrode placement used in the clinic. The currents and electric fields, thus, produced within the model are computed using the same three-dimensional impedance method as used for the @entity9808 case. The ECT calculations are made using currents and wave forms typical in the clinic. The electrical tissue properties are obtained from a 4-Cole-Cole model. The numerical results obtained are shown on a two-dimenaional cross section of the model. In this study, we find that the current densities and electric fields in the ECT case are stronger and deeper penetrating than the corresponding @entity9808 quantities but both methods show biologically interesting current levels deep inside the brain.
