Electrostatic shield for diathermy treatment head

• US 4,068,292 A
• Filed: 07/22/1976
• Issued: 01/10/1978
• Est. Priority Date: 03/27/1975
• Status: Expired due to Term

• Current Assignee: International Medical Electronics Limited
• Original Assignee: International Medical Electronics Limited
• Inventors: Berry, Fred M., Shirley, James N.
• Primary Examiner(s): Moose, Jr., Harry E.
• Application Number:
  US05/707,529
• Time in Patent Office: 537 Days
• Field of Search: 219/6.5, 219/10.5 SF, 219/10.81, 219/10.57, 219/10.41, 219/10.43, 128/404, 128/411, 128/418, 128/421, 128/422, 361/212, 361/437
• US Class Current: 361/437
• CPC Class Codes: A61N 1/06 for high-frequency therapy
• CPC Class Codes: A61N 1/403 for thermotherapy, e.g. hyperthermia

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.

Claims

1. An electrostatic shield for use with shortwave diathermy apparatus having a diathermy applicator head, said shield adapted to be located between the diathermy applicator head having current carrying coils therein and the body of the patient being treated, said shield comprising:

means for attenuating electrostatic energy emanating from said head reaching said patient, said attenuating means comprising electrically conductive strips located between said current carrying coils in said head and said patient; and

means for grounding and attenuating means.

2. The combination as in claim 1 wherein said strips define a plane which is substantially parallel to the plane of said coils.

3. The combination as in claim 1 including means for mounting said shield on said applicator head.

4. The combination as in claim 3 wherein said strips define a plane which is substantially parallel to the plane of said coils.

5. The combination as in claim 1 including loop means for reducing electrostatic fringing, said loop means being electrically connected to said attenuating means.

6. The combination as in claim 5 wherein said strips define a plane which is substantially parallel to the plane of said coils and the plane of said loop.

7. The combination as in claim 6 wherein said loop is substantially the size of said applicator head.

8. The combination as in claim 6 wherein said strips extend generally radially outwardly from the center of the area defined by said loop, said strips being electrically connected to said loop.

9. The combination as in claim 8 wherein the center of the area defined by said loop has at least a portion thereof which is not occupied by said strips.

10. The combination as in claim 8 wherein said strips are coplanar with said loop.

11. The combination as in claim 10 wherein the center of the area defined by said loop has at least a portion thereof which is not occupied by said strips.

12. The combination as in claim 11 including means for mounting said shield on said applicator head.

13. A variable electrostatic shield for use with shortwave diathermy apparatus, said shield adapted to be located between a diathermy applicator head having current carrying coils therein and the body of the patient being treated, said shield comprising:

first and second shield surfaces, each of said surfaces comprising means for attenuating electrostatic energy reaching said patient and loop means for grounding said attenuating means, said attenuating means comprising a plurality of electrically conductive strips located between said current carrying coils and said patient; and

means for mounting said first shield surface for rotation with respect to said second shield surface.

14. The combination as in claim 13 wherein said strips are oriented substantially perpendicular to said loop means.

15. The combination as in claim 13 wherein said first and second shield surfaces have a central area which is not occupied generally radially outwardly from said area.

16. A method for using a radio frequency diathermy apparatus with at least one applicator head in therapeutic heat treatment of internal body tissues and for simultaneously limiting the surface skin heating associated with said treatment, said method comprising the steps of:

generating radio frequency electric currents in said diathermy apparatus to thereby produce electrostatic and electromagnetic energy in said treatment head;

directing said electrostatic and electromagnetic energy toward the body tissue via said diathermy applicator head;

attenuating at least a portion of said electrostatic energy reaching the exterior skin surface to thereby limit said exterior heating effect; and

transcutaneously heating the body tissue to be treated by said electromagnet energy.

17. The method as in claim 16, wherein the attenuating step includes locating an electrostatic shield means between said diathermy applicator head and the exterior skin surface.

18. The method as in claim 16, wherein the attenuating step includes mounting the electrostatic shield means on said diathermy applicator head.

19. The method as in claim 17, wherein the step of attenuating said electrostatic energy includes the further step of varying the effect of the electrostatic shield means on the electrostatic energy thereby controlling the amount of electrostatic energy passing through said electrostatic shield means.

20. The method as in claim 18, wherein the step of attenuating said electrostatic energy includes the further step of varying the effect of the electrostatic shield means on the electrostatic energy thereby controlling the amount of electrostatic energy passing through said electrostatic shield means.