US Patent 8454591 Subcutaneous electric field distribution system and methods

Apparatus and methods for dynamically controlling electric field distribution within tissue disposed at various depths beneath the skin at a target region of a patient's body by independently controlling the electric potential of each of a plurality of electrodes in relation to the electric potential of a ground pad. By controlling electric field distribution during a procedure, a target tissue at particular depths beneath the skin can be selectively heated relative to adjacent non-target tissue. At least one of the electrodes and the ground pad may comprise a spiral inductor comprising a substantially planar spiral of electrically conductive material.