Electrostatic shield for diathermy treatment head

Abstract

Method and apparatus for minimizing or preventing the deleterious skin heating effects associated with conventional short wave diathermy treatment. The disclosed method includes attenuation of the electrostatic field transmitted by the applicator head and transcutaneous transmission of the radiated electromagnetic energy substantially unimpeded to the deep body tissues to be treated. The attenuation of the electrostatic field is performed by an electrostatic shield, which is adapted to be positioned on the diathermy applicator head between the radiating electrode and the patient receiving treatment. However, the radiated electromagnetic field, which is primarily responsible for the therapeutic generation of heat in relatively deep body tissues, passes through the shield substantially unimpeded. The shield comprises a plurality of narrow, preferably metallic, spaced apart strips and an electrically conductive loop which surrounds the strips and is coplanar therewith. Each of the strips are oriented generally perpendicular with respect to both the current carrying coils in the applicator head (on which the shield is mounted) and the loop. The strips extend generally radially outwardly from the loop center area toward the loop, to which each of the strips is electrically connected. So positioned, the strips impede electrostatic field radiation while facilitating passage of the electromagnetic field. The loop further reduces electrostatic field radiation by discouraging fringing effects, but its radius is sufficiently large to prevent interference with the radiated magnetic field.