WO2001006943A1 - Electromagnetic scalpel for the heating of biological tissue - Google Patents

Abstract

Electromagnetic scalpels for use on biological tissue. The devices accomplish the tasks of tissue heating, ablation, and even cauterization without electrodes, by directing electromagnetic energy to the tissue. The structure of one of the novel devices consists of four separate 'U' -sphaped ferrite cores (30, 32, 34, 36) oriented at 90 degrees to each other, each with one of their respective legs in contact and parallel to the other three, and with their respective 'U' openings facing the same way. Wrapped around the four legs in contact is a single winding (28) of conductive metal with the winding filling the spaces formed by the 'U' -shaped cores.

Description

Electromagnetic Scalpel for the Heating of Biological Tissue

Inventor: Kent Davey New Smryna Beach, Florida

Related Applications

The present application claims the priority of U.S. Provisional Application Serial

No. 60/145,754, filed July 27, 1999, and U.S. Provisional Application Serial No.

60/147,868, filed August 9, 1999, the contents of which are hereby fully incorporated

herein by reference.

Field of the Invention

The present invention relates to devices and methods for heating and excising

tissues of the human body.

Background of the Invention

Collagen connective tissue is the major protein found in the human body. It

provides the cohesiveness of the musculoskeletal system, the structural integrity of the

viscera, and the elasticity of integument. Intermolecular cross links provide collagen

connective tissue with unique physical properties of high tensile strength and substantial

elasticity.

A previously recognized property of collagen is hydrothermal shrinkage of collagen

fibers when elevated in temperature. This unique molecular response to temperature

elevation is the result of rupture of the collagen stabilizing cross-links. When heated, the

protein fibers adjust their linkage causing the fiber length to shorten, with an immediate contraction of the collagen fibers to about one-third of their original dimension. In the

process the cells within the matrix are usually destroyed. The new cell growth takes place

within either of the ends.

Two prominent patents that use radio-frequency injected current to accomplish the

dimensional contraction are U.S. Patents 5,569,242 to Lax, et. al, Oct. 29, 1996 and United

States Patent 5,458,596 to Lax, et. al., Oct. 17, 1995. There, a probe is employed with a

lead injection electrode and a trailing band electrode as part of a 2.3 mm laproscopic probe.

There are multiple patents that utilize RF electrical energy with electrodes in a

catheter or endoscope to accomplish tissue ablation. Among those are: United States

Patent No. 5,843,075, issued to Taylor Dec. 1, 1998, and entitled "Probe for Thermal

Ablation"; United States Patent No. 5,906,613 issued to Mulier, et. al. May 25, 1999, and

entitled, "Method for R-F ablation"; United States Patent No. 5,893,885 issued to Webster,

Jr. on Apr. 13, 1999 and entitled "Multi-electrode Ablation Catheter"; United States Patent

No. 5,837,001 issued to Mackey on Nov. 17, 1998 and entitled "Radio Frequency Energy

Delivery System for Multipolar Electrode Catheters"; United States Patent No. 5,807,395

issued to Mulier, et. al. on Sept. 15, 1998, and entitled "Method and Apparatus for RF

Ablation and Hyperthermia"; United States Patent No. 5,540,681 issued to Strul, et. al. on

Jul. 30, 1996, and entitled "Method and System for Radiofrequency Ablation of Tissue";

United States Patent No. 5,545,161 issued to Imran on Aug. 13, 1996, and entitled

"Catheter for RF Ablation Having Cooled Electrode with Electrically Insulated Sleeve";

United States Patent No. 5,472,441 issued to Edwards, et. al. on Dec. 5, 1995, and entitled

"Device for Treating Cancer and Non-malignant Tumors and Methods"; United States

Patent No. 5,348,554 issued to Imran, et. al. Sept. 20, 1994, and entitled "Catheter for RF Ablation with Cooled Electrode"; United States Patent No. 5,125,928 issued to Parins, et.

al. Jun. 30, 1992, and entitled "Ablation Catheter with Selectively Deployable Electrodes";

and United States Patent No. 4,945,912 issued to Langberg on Aug. 7, 1990, and entitled

"Catheter with Radiofrequency Heating Applicator". The disclosures of those patents are

fully incorporated herein by reference.

Discussed in those patents are various shapes and configurations of electrodes,

methods of cooling the electrode tips, and control of their excitation. The devices are used

both in excising tissue and in hyperthermia treatment for cancer.

Other applications of such methods include subluxations and dislocations, both of

which are a common occurrence and cause for a large number of orthopedic procedures

each year. Symptoms include pain, instability, weakness, and limitation of function. If the

instability is severe and recurrent, functional incapacity and arthritis may result. Surgical

attempts are directed toward tightening the soft tissue restraints that have become

pathologically loose. These procedures are typically performed through open surgical

approaches that often require hospitalization and prolonged rehabilitation programs.

More recently, endoscopic (arthroscopic) techniques for achieving these same goals

have been explored with variable success. Endoscopic techniques have the advantage of

being performed through smaller incisions and therefore are usually less painful. They are

performed on an outpatient basis and often under local anesthesia, and are associated with

less blood loss, lower infection risk, and have a more cosmetically acceptable scar.

Postoperative recovery is often faster than using open techniques.

It has been shown that cartilage and even the disks in the spinal cord exhibit the

same property of contraction upon heating as discussed above. When cartilage becomes torn, and the ends remain attached to their respective joints, the usual procedure is to

surgically reattach the lengthened cartilage. The healing time for this prior art procedure

is typically approximately 6-8 weeks. Localized heating of the same lengthened cartilage

tightens the joint and greatly reduces the healing time to approximately 2-4 weeks.

Heating a herniated disk in the back has the effect of shrinking the disk, allowing it to pull

away from the irritated nerves. If the energy source is localized enough, it can be used to

cauterize blood vessels that might have grown into the enlarged disk. The ideal

temperature for heating tissue seems to be about 149 ° F.

There has been discussion in the existing literature regarding alteration of collagen

connective tissue in different parts of the body. One known technique for effective use of

this knowledge of the properties of collagen is through the use of infrared laser energy to

effect tissue heating. The use of infrared laser energy as a corneal collagen shrinking tool

of the eye has been described and relates to laser keratoplasty, as set forth in U.S. Patent

No. 4,976,709 (which is fully incorporated herein by reference). Controlling the

localization, timing and intensity of laser energy delivery is paramount in importance for

providing the desired soft tissue shrinkage effect without creating excessive damage to the

surrounding non-target tissues.

U.S. Patent No. 5,458,596, which is incorporated herein by reference, discloses an

apparatus and method for controlled contraction of soft tissue utilizing RF energy. The

shift from laser light to radio waves reduces the frequency of the radiation and,

consequently, the treatment temperature. The technology of the '596 patent utilizes an

electrode which can be inserted into the connective tissues of the human body (as a probe)

for the delivery of energy to the tissue to achieve a desired contraction of the collagen fibers.

These newer probes can also be applied for treating damaged spinal disks. A spinal

disk consists of rings of ligaments around a gel-filled center. When the ligaments are torn,

blood vessels grow into the tear, bringing nerve endings with them. Bending of the spine

squeezes the nerves and causes pain. Traditionally there have been two approaches to this

problem: remove the damaged disk or fuse together the vertebrae on either side of it using

screws with plates or rods. Another version of that surgery involves going through the

patient's abdomen from the front, pushing past the stomach and other organs to the spine

and inserting a titanium to immobilize adjacent vertebrae. These cage insertions seem to

require a long time for healing.

The spinal probe is less invasive. Under local anesthetic, using an X-ray machine,

the damaged disc is pinpointed and the probe is inched through the ligaments into the gel-

filled center of the disk. Once the flexible, wirelike probe is coiled around the inside of

the disk, the power is turned "on" at the probe's control console. The heat of the activated

probe shrinks the stretched-out rings of collagen and cauterizes the blood vessels and

nerves that have crept into the ligament layers.

To minimize damage from the intrusion, the diameter of the probe has to be very

small. However, it is difficult to achieve the required frequency of radiation using a small

probe. Accordingly, there is a substantial interest in the field for new devices and methods

to accomplish tissue heating in connection with the above described problems and

procedures. Summary of the Invention

It is an object of the present invention to accomplish the various tasks of heating,

ablation, and even cauterization without electrodes.

It is an object of the present invention to efficiently direct adequate heating energy

to biological tissue using a small probe for precise delivery to biological tissue.

It is another object of the present invention to non-invasively induce heating

through the skin to heat tissue located beneath the skin.

In accordance with the invention, various electromagnetic scalpels are provided

herein. The scalpels allow action to be taken on biological tissue using electromagnetic

energy.

In accordance with one embodiment of the present invention, the various tasks of

heating, ablation, and even cauterization without electrodes, by using frequencies outside

of the RF band is accomplished. Eliminating electrodes allows the procedures to be

performed less invasively, since the device need not be in direct contact with the tissue to

be treated. This is especially advantageous when the objective is only heating. Eliminating

electrodes reduces the risk of electrode contamination since half cell reactions are

eliminated. Operating outside the RF band increases the efficiency of tissue energy transfer

since the water molecules absorb more energy to reorient in their polarization direction;

the permittivity has a much stronger imaginary component from 900 MHz to 2 Ghz. The

process does not depend on thermal heat transfer since the energy is induced preferably at

the site of interest. Both external and miniaturized internal embodiments are presented

towards this end.

In a further embodiment of the present invention, a novel construction of the probe is provided employing a ferrite core and a steel wire. The combination of these two

elements permits reduction of the size of the probe while offering a low reluctance

magnetic path. The path would normally contribute to fringe field production, but in this

case those fringe fields can be effectively used to induce heating in the surrounding tissue.

In a further embodiment, the heating is realized non-invasively by utilizing a

concentric cylinder arrangement. The resulting cup structure can be placed against the

skin. When the windings within the cup are excited, heating is induced through the skin.

If the surface of the cup is cooled, the surface of the skin can be cooled while heat is

injected underneath the skin. The depth of penetration is controlled by altering the inner

and outer diameter of the cylinder.

Further embodiments, objects, advantages and features of the inventions will

become apparent in conjunction with the disclosure provided herein.

Brief Description of the Drawings

A full understanding of the invention can be gained from the following description

of the preferred embodiment when read in conjunction with the accompanying drawings

in which:

Figure 1 is a cross-sectional view of one embodiment of the present invention, a

probe used for inducing eddy currents into surrounding connective tissue. Only one half

of the probe, the other half is formed by rotation about the vertical central axis.

Figure 2 is a partial cross-sectional view of another embodiment of the probe,

showing the right half only (for simplicity of illustration) of a disk-shaped probe. The

segment in the figure is the right half of the probe shown extending off of the central axis of the disk, the central axis being shown in dotted outline. (A rotation of the section of

probe 18 around the central axis results in the disk shape of the entire probe.)

Figure 3 is a partial cross-sectional view of the embodiment shown in Figure 2,

where the winding has a greater radial spread.

Figure 4 is a front perspective view of the stimulation unit comprised of four

separate "U"-shaped cores, which is utilized in accordance with the present invention to

accomplish heating of the tissue non-invasively.

Figure 5 is a back perspective view of the stimulation unit shown in Figure 4, also

comprised of four separate "U"-shaped cores.

Figure 6 is a cross-sectional view of the arrangement shown in Figs. 4 and 5;

Figures 7(a) and (b) are perspective views of one of the "U"-shaped cores of Figures

4, 5 and 6, showing its preferred dimensions, in inches;

Figure 8 shows a nanocrystalline slab upon which a 1 turn coil has been placed,

with Figure 8(a) being a top view and Figure 8(b) being a perspective view of the slab;

Figure 9 is a schematic diagram illustrating an excitation circuit to cancel the

inductive reactance and yield a 50 ohm load for the transmission line coupling.

Figure 10 shows a magnetic thermal heater and ablation tool comprised of a steel

winding and ferrite core, with Figure 10(a) being a cross-sectional view of the embodiment,

and Figure 10(b) illustrating typical magnetic field lines for the reduced in size device

shown in Figure 10(a).

Figure 11 is a perspective view of a toroidal core with a winding placed at the tip of

a laparoscope.

Figure 12 is a perspective view showing the use of a leaky resonant cavity to provide the high frequency field induction to the collagen tissue.

Table I show the range of materials which can be used for the devices shown in

Figure 10 and the resulting induced power.

Detailed Description of the Figures and the Preferred Embodiments

In accordance with the present invention, electromagnetic (EM) scalpels are

provided for use on biological tissue within the anatomy. The EM scalpel directs

electromagnetic energy into the desired area of the anatomy resulting in heating of the

tissue or even excising it. The scalpels can either be totally non-invasive (e.g. by directing

the radiation through the skin) or can operate by insertion into the appropriate body area.

In accordance with one embodiment of the present invention, as shown in Figure 1,

a small electromagnetic scalpel or probe 10 is provided by insertion into the ligaments,

joint capsules and other connecting tissues of the human body. The probe is inserted for

the purpose of delivering RF energy to these tissues to induce their contraction.

As shown in Fig. 1, the probe 10 is comprised of a small diameter ferromagnetic

core 12 and a winding 14. The diameter of the probe is preferably about 2 mm, 1 mm for

the core and Vi mm on each side of the coil winding. In one embodiments, an air core and

a copper or steel winding can be used. In the preferred embodiment, however, the

inventor has found that a 42% improvement in heating power is achieved through the use

of steel wire in place of a copper wire.

Insertion of a ferrite core instead of the air core further increases the heat intensity,

compared with an air core probe, allowing for increase in power without increasing the

size of the probe. The combination of the ferrite core and steel winding offers a low inductance magnetic path. The path would normally contribute to fringe field production,

but in this case, the fringe fields are used to induce heating in the surrounding tissue.

Alternatively, the small diameter of the probe can also be achieved by using an iron

wire and a solenoidal winding. Such combination allows the injection of heat into the

ligaments or other connective tissue while minimizing the damage to the surrounding

tissue.

Another possible design of the probe, in accordance with the present invention, is

shown in Fig. 2. In this embodiment, the probe 16 is in the form of a disc preferably 2.1"

in diameter and 0.25" thick (with only the right half of the disks being shown in the

illustrations of Figures 2 and 3). Although 0.25" in thickness is preferred, the thickness of

the device can be made smaller as far as the fields are concerned. The thickness has been

added in this embodiment to give the device some structural integrity. The ferrite core 18

is notched to house the steel winding 20. The annular winding extends around the disk

near the disk's outer circumference. The width of the notch 22 is preferably 0.22" and its

height is 0.0625". The inner diameter of the coil notch is preferably 1.5". A wider

winding 20, shown in Figure 3, will reduce the injected power due to eddy currents in

winding. Not properly winding the core also reduces the power.

This embodiment is more suitable for delivering higher EM frequency. At the

frequency of 915 MHz, and an excitation of 1.78 A, this device is capable of injecting 50

watts of power into the connective tissue. If, alternatively, the winding 20 has a greater

spread, as shown in Fig. 3, the field also spreads out and delivers 50 watts of power with

the same frequency when 2.8 A are driven through the winding.

Another embodiment of the present invention is shown in Figures 4, 5 and 6. In this embodiment, the heating is realized non-invasively by utilizing a concentric cylinder

arrangement 24. This consists of four (4) U-shaped cored with a winding encircling one leg

of each of the cores (the center common legs). The resulting cup structure can be placed

against the skin. When a winding 28 within the cup is excited, heating is induced through

the skin. If the surface of the cup is cooled, the surface of the skin can be cooled while heat

is injected underneath the skin. The depth of penetration is controlled by altering the

inner and outer diameter of the cylinder.

As shown in Figs. 4 and 5, one stimulation unit is comprised of four separate "U" -

shaped ferrite cores 30, 32, 34, 36. The white "U"s 30 and 32 and the black "U"s 34 and 36

are constructed of a suitable magnetic material. Preferably, grain oriented steel is used (4%

grain oriented steel in particular), wound on a mandrel using 2 mil stock. The smallest 2

mil laminations from National Magnetics are suitable for this application. In the preferred

embodiments of all of the inventions of the present application, the cores are

ferromagnetic. Although 4% grain oriented steel is one preferred material for the cores,

alternatively, the cores can be constructed of nanocrystalline materials, vanadium

permendur, orthinol, metallic glasses (metglass), permalloy, supermalloy, powdered iron,

ferrite, or a different silicon iron or silicon steel (e.g. 3% grain oriented steel, also known as

magnesil).

Two "U"-shaped cores are placed back to back, the white pair 30 and 32 in Figs. 4,

5 and 6, while the other two, the black pair 34 and 36, are placed against the first two (the

second pair preferably being at a 90 degree angle to the first pair). Preferred dimensions of

the "U"s are shown in Fig. 7. In that embodiment, all four of the ferrite cores have the

same dimensions. The single winding 28 is wound around the interior legs of the cores, i.e. located within the cut out portions 38, the space between the legs of the "U"s. When

all cores are arranged as shown in Fig. 4, the primary field is driven up the common center

40.

According to empirical analysis, when the cylindrical arrangement 24 is run with

linear ferrite, the power dissipation is 25 W. When, however, it is run with nonlinear

saturable ferrite, the power dissipation drops to 5 W. In this case, ferrite is heavily

saturable. If 100 MHz frequency is applied to the device 24, shown in Figs. 4 and 5,

utilizing steel cores, the injected heat has a skin penetration depth of 1.25 mm. To achieve

this result, it is preferable to use a 100 MHz sine wave function generator and an amplifier

with a bandwidth from 1 MHz to 100 MHz. These results assume a copper winding; the

power coupling is increased if the winding is altered to steel. It is also preferable to

associate a temperature probe transducer, along with the device, to monitor function and

prevent overheating of the skin.

Alternatively, it is possible to use the above described stimulation unit with

relatively high frequencies, preferably 915 MHz. At this frequency, water has both a real

and an imaginary permittivity, when the fluid begins to absorb energy in conjunction with

the electric dipole reversals.

In a further embodiment of the invention, the electromagnetic scalpel, as shown in

Figure 8, consists of a ferromagnetic wafer or laminated slab 110 upon which is placed a

one turn winding 120. Typical slab dimensions are 1.25" square on the face, by 0.5" of

depth of thickness. The slab is laminated with ferromagnetic material having a tape

thickness of one mil or less. It is important that the material be low loss, having both a

high resistivity and low hysteresis losses. In one embodiment, the typical excitation frequency is 915 MHz. Since the device will radiate electromagnetic energy, it is desirable

that it radiate away from the slab; hence the slab material is chosen to be ferromagnetic. In

the preferred embodiment, a laminated nanocrystalline slab is used, which meets the

requirements of keeping the energy radiating away from the slab, while the 1 mil

laminations help curtail losses. Nanocryatalline is also considerably lower in hysteresis

and magnetostrictive losses than silicon steel. The nanocrystalline material also has a high

permeability, although that property is not necessary for this embodiment.

Operation of this embodiment at high frequencies helps for two reasons. First, the

power induced in the body is proportional to frequency squared. Second, water becomes

more absorptive at higher frequency; the permittivity has an imaginary component

indicating that power is being consumed just to reorient the polar molecules comprising

the fluid. The higher frequencies lead to problems with the inductive reactance. This

reactance is extremely high (> 400 Ω). It is desirable to both cancel out that inductive

reactance and to couple power into the device using a 50 Ω transmission line. One circuit

for accomplishing this end is shown in Figure 9. The ferromagnetic wafer 110 appears as a

large inductive load. A capacitor 130 (C,) is chosen to resonate with the inductive load 110.

The coil of the wafer 120 may be shimmed off the wafer to aid in getting the system into

resonance. Approximately 1/8 of a wavelength back from the load, a capacitor 140 (C_j) is

placed across the line to cancel the imaginary component of the load. The exact distance is

found in the conventional manner from a Smith chart when the real component of the line

impedance becomes 50 Ω. The capacitor is chosen to cancel the reactive component at that

point.

The first two patents cited in the Background of the Invention section above discuss an RF electrode which is configured to be placed in a small laparoscope or endoscope

about 2.3 mm in diameter. Both ablation and heating are accomplished by the direct

injection of RF current through electrodes at the tip of the probe. In contrast, the present

inventions accomplish the same results but by using magnetic fields, i.e. without electrodes

and without the commensurate fear of electrode - tissue contamination.

Shown in Figure 10 is another embodiment by which this is accomplished. As

shown in Figure 10(a), this embodiment consists of a solenoidal winding 160 with an

internal core or ferrite 170. (This figure is similar to Figure 1). This apparatus constitutes

the tip of a laparoscopic instrument. The outer medium 150 is the polyelectrolytic solution

to be heated. Each of the regions 160 and 170 are 0.5 mm radial thickness by 10 mm long

in an axisymmetric geometry. The outer test region 150 has a typical radius of 5 mm by 20

mm long. Typical field lines 180 for this axisymmetric geometry are shown in Figure

10(b).

There are 4 options for the composition of regions 160 and 170, listed in Table I.

The winding 160 can be wound with copper or steel wire. The inner sleeve of the solenoid

170 can be filled with the ambient polyelectrolytic (saline, for example) by leaving it open,

or it can be filled with ferrite. Each case was worked out with a boundary element code

and the loss in the surrounding polyelectrolytic fluid 150 computed with a current density

of 3.0 x 10⁶ A/m² and 10⁸ Hz. The results, shown in Table I, clearly indicate the advantage

of using steel wire with a ferrite core.

Another way of injecting heat magnetically with a miniaturized scope probe is

shown in Figure 11. A toroidal core 190 is preferably wound with copper winding 211.

The core is wound with a very fine tape of ferromagnetic material on a mandrel. Typical dimensions of the tape is 1 mil thick by 8 mm width, and it extends past the tip of the

nonconducting laparoscope or endoscope 210 by about 2 -5 mm. Preferably, the copper

winding or core coil is wrapped from the outer cylindrical surface of the toroid and into

the inner cylindrical surface of said toroid. When excited with current at high frequency,

interstitial current is induced to flow down or through the center of the toroid, in the

same loop that the exciting current follows.

An additional embodiment is shown in Figure 12. A closed conducting waveguide

220 such as aluminum, with a cavity therein, is designed to resonate at a frequency near

915 MHz. The waveguide may be dielectrically loaded so that smaller dimensions can be

employed to yield this resonance frequency. A coaxial loop antenna 222 or dipole antenna

extending into the cavity of the waveguide, excites the waveguide, injecting energy from an

RF oscillator. A hole 224 is cut in the upper sidewall of the waveguide to allow leakage of

the field into the surrounding space. The advantage of the resonant cavity approach is that

the field pattern witnessed by the patient is less dependent on the shape of the exciting

antenna. The present embodiment avoids the problem of concentrating the field in the

location of the antenna, and allows a broader field to emanate from the hole in the cavity.

Having described this invention with regard to specific embodiments, it is to be

understood that the description is not meant as a limitation since further embodiments,

modifications and variations may be apparent or may suggest themselves to those skilled in

the art. It is intended that the present application cover all such embodiments,

modifications and variations.

Claims

ClaimsWhat is claimed is:

1. An apparatus comprising: an electromagnetic scalpel.

2. An apparatus compπsing:

an electromagnetic scalpel, said electromagnetic scalpel comprising at least two

attached U-shaped cores, each of said U-shaped cores comprising at least two legs

and a cut out portion;

a coil located in said cut out portions of said U-shaped cores; and

a source of RF energy connected to said coil for injecting RF energy into said coil.

3. An apparatus as claimed in Claim 2, further comprising a first pair of U-shaped

cores, and a second pair of U-shaped cores, said first pair of U-shaped cores

comprising two U-shaped cores located adjacent to each other in a straight line, said

second pair of U-shaped cores comprising two U-shaped cores located adjacent to

each other in a straight line, said first pair of U-shaped cores being oriented

perpendicular to said second pair of U-shaped cores.

4. An apparatus as claimed in Claim 3, wherein said first pair of U-shaped cores

comprises a first center, and said second pair of U-shaped cores comprises a second

center, said first center overlapping with said second center.

5. An apparatus for non-invasively delivering RF energy to ligaments, joint capsules

and connective tissue to effect the contraction of collagen fibers according to

Claims 2 through 4, wherein said U-shaped cores comprise 4% grain oriented steel.

6. An apparatus comprising:

an electromagnetic scalpel, said electromagnetic scalpel comprising a core having a

small diameter, said core comprising a coil located on said core and producing eddy

currents when activated, and a source of RF energy connected to said coil for injecting RF

energy into said coil.

7. An apparatus as claimed in Claim 6, wherein said core further comprises a

cylindrical shape.

8. An apparatus as claimed in Claim 6, wherein said core further comprises a shape of

a disk and said coil is located in a notch on the face of said disk.

9. An apparatus as claimed in Claim 6, wherein said core is a ferrite core.

10. An apparatus as claimed in Claim 6, wherein said coil is a steel coil.

11. An apparatus as claimed in Claim 6, wherein said coil is a copper coil.

12. An electromagnetic scalpel comprising: a laminated wafer underlay with a coil

winding placed on top of the wafer, and excited with a high frequency power

supply in a resonance condition.

13. An electromagnetic scalpel comprising: a solenoidal ferromagnetic winding

wrapped around a low loss ferromagnetic core such as ferrite to induce current and

commensurate heating; said unit being affixed to the tip of a laparoscope or

endoscope type tube.

14. An electromagnetic scalpel, comprising:a laparoscope or endoscope type tube

comprising a magnetic toroid, said toroid comprising a coil, said toroid being at the

tip of said laparoscope or endoscope type tube.

15. An electromagnetic scalpel as claimed in Claim 14, wherein said coil is wrapped

from the outer cylindrical surface of said toroid and into the inner cylindrical

surface of said toroid.

16. An electromagnetic scalpel as claimed in Claim 14, wherein said device induces

current flow down the center axis of said laparoscope or endoscope.

17. An electromagnetic scalpel comprising: a resonant waveguide cavity, said cavity

being excited by means of a loop or dipole antenna, said cavity comprising a hole in

a side of said waveguide.

18. An electromagnetic scalpel as claimed in Claim 17, wherein said hole allows energy

to be coupled in a localized region to adjacent tissue through the hole to the

exclusion largely of the antenna shape.