by the cylindrical electrode 12, it is not desireable to PLANAR DISC MAGNETIC ELECTRODE merely shorten the height of the cylinder to reduce the
side radiations. What is necessary for such treatment is BACKGROUND OF THE INVENTION an electrode which will produce a field of energy (and
This is a Continuation-in-part of my prior application 5 thus the abilitV to, heat) substantially entirely in the Ser. No. 97,485, filed Nov. 26, 1979, now abandoned. immediate area within the center section of the elecThe present invention relates to electrodes used in trode while providing the optimum L/C ratio to minimedical treatment and, more particularly, to electrodes mize voltage build-up which would also produce localemployed with radiofrequency energy to produce deep ized skin and fat heating.
heating by hyperthermia. 10 Wherefore, it is the object of the present invention to
The therapeutic effects of heat have been known for provide an electrode for use in medical treatment by a long period of time. In particular, it has been found hyperthermia using the magnetic field approach which that tumors can be heated and, thereby, destroyed. electrode concentrates the energy in a plane.
Likewise, it has been known that radiofrequency energy can be employed to cause heating of animal tissue.
This has been accomplished by traditional diathermy The foregoing objectives have been met in an elecapparatus. trode for use in the treatment of animal tissue by hyperInmyU.S. Pat. No. 4,186,729, an electrode is shown thermia comprising electrically conductive material which allows radiofrequency energy to be employed to disposed to from a single turn self-resonant loop and cause deep heating within an animal body. A simplified 20 adapted for coupling to a supply of radiofrequency drawing of an electrode as disclosed therein is shown in energy by the improved configuration comprising the FIG. 1. Prior to my Deep Heating Electrode, a person electrically conductive material comprising a plurality 10 having a tumor situated deep within his body was of pianar members being shaped in the form of partial virtually unable to have sufficient energy transferred annular disk segments, said members being disposed in thereto to cause thereapeutic heating of the tumor. 25 ... spaced relationship with a dielectric mateBefore my invention, such heating could only occur by ria, disposed between the overlapped portions to form surgically exposing the tumor and placing traditional an annular djsk electrode which is self-resonant. dmthermy electrodes in electrical contact with oppos- In the ferred embodiment) this objective is accom
... ... ... ... 30 Plished bvan electrode comPrisingtwo virtually semi. '• _■• , J • 4.1. i. annular conductive disk members, each having an outAccording to my invention as disclosed in the above- ., c J • -J J- C T-1-4 J-1 c J ... c r side radius of r0 and an inside radius of r,-. The two disk
referenced patent, an electrode 12 in the form of a cyhn- , . ,. , , x ,' . , . .
der, as shown, can be placed about the body of the membersare,placed 1"sfacedend"t0:efdrelationshipm person 10 over the area of the tumor and deep heating ^ommon plane A dielectric material is placed across energy transmitted thereto if the electrode 12 is in the 35 two gaps and a second pair of partial-annular conform of a single turn self-resonant loop which causes a ductlve dlsk members> each having an outside radius of series of concentric force lines of substantially equal r° and an lnslde radlus of r<> are disposed symetncally energy to be created inside the cylinder. across the SaPs m contact with the dielectric material.
The construction of such electrodes is typified by the The arc len8th of the second Pair of disk members is example of FIG. 2 which appeared as FIG. 8 in the 40 determined by the amount of capacity required to bring above-referenced patent. In that embodiment, electrode the structure to resonance and the capacity per unit 12 comprises two semi-cylindrical members 14 of an length. The maximum arc length occurs when the secelectrically conductive material. Members 14 are dis- ond conductive disks have an arc length equal to the posed in overlapped spaced relationship as shown to first (e-g-, with the preferred embodiment, when almost form the cylindrical electrode 12. While air can be em- 45 equal to 180°). This will most often be the case when the ployed as the dielectric material between the over- dielectric material thickness has been increased such as lapped ends of semi-cylindrical members 14, materials for breakdown power considerations, and less capacity such as plastic can also conveniently be used and the Per umt length is obtained.
entire assembly bonded together to form a more usable I" alternate embodiments, the pair of semi-annular and durable electrode. The area of overlap and the 50 conductive disk members are replaced by a plurality of dielectric material are chosen such that when electrode end-spaced partial-annular members totaling 360°. The 12 is excited by connecting it to a source of radiofre- gaps are then covered with the dielectric material and quency energy as by the leads 16, the inductance of the second partial-annular members as with the preferred single turn loop thus formed and the capacitance of the embodiment.
overlapped ends will place the circuit in resonance for 55 DESCRIPTION OF THE DRAWINGS
maximum energy transfer.
As can be visualized, if the electrode 12 of FIG. 1 FIG. 1 is a simplified drawing of a prior art electrode with its relatively broad field distribution were used to disposed for treatment of a human patient, treat a tumor within the neck of a person 10, it would be FIG. 2 is a simplified drawing showing a typical impossible to transfer therapeutic energy into the neck 60 construction embodiment for prior art electrodes such without causing energy to also enter the brain itself. as the one of FIG. 1.
Since deep heating energy may have a detrimental ef- FIG. 3 is a simplified drawing showing the electrode feet on the brain, an electrode which produces a narrow of the present invention positioned for treatment of the field is desired. The potentially toxic effects on the brain neck area of a human patient.
can be further evaluated with the present invention 65 FIG. 4 is a plan view of the electrode of the present when properly positioned. invention in its preferred embodiment, shown with
Because of the required optimum relationship be- minimum gap coverage, tween the inductance (L) and capacitance (C) formed FIG. 5 is an edge view of the electrode of FIG. 4.