WO2014020584A1

WO2014020584A1 - System and method for treating tissue

Info

Publication number: WO2014020584A1
Application number: PCT/IL2012/050279
Authority: WO
Inventors: Eliezer FUCHS; Iftach YAFE; Moshe Azoulay
Original assignee: Medischarge Ltd.
Priority date: 2012-07-29
Filing date: 2012-07-29
Publication date: 2014-02-06

Abstract

A system for treating tissue and a method utilizing same are provided. The system includes a signal generator for generating an electrical signal and a discharge head for converting the electrical signal to a discharge signal. The discharge signal is capable of initiating an electron gradient with respect to the tissue, the electron gradient capable of generating a steadily increasing self-terminating electrical current at a substantially stable electrical potential between the discharge head and the tissue.

Description

SYSTEM AND METHOD FOR TREATING TISSUE

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a system and method for treating tissue via administration of a highly selective energy beam. Specifically, the present invention relates to a system capable of subjecting tissue such as skin to a gradient of electrons and electromagnetic waves capable of treating a tissue or pathologies thereof without substantially harming non-treated tissues.

Existing approaches for treating tissue such as skin are based on drugs, surgical procedures as well as various forms of energy treatment approaches. Laser and other forms of energy are routinely used for both therapeutic and aesthetic treatments.

The therapeutic effects of various forms of electric discharge have been known since the late 1800s (see, for example, www.meridianinstitute.com/eaem/halliwel/hallcont.html). More recently, other modes of electric discharge have been suggested for treatment of human tissues including the utilization of electric discharge plasma through a mechanism which is similar to dielectric barrier discharge.

Electric discharge can take one of several forms depending on the electrical potential and medium between the electrodes. Figure 1 is a graph illustrating the three main types of discharges - dark discharge (A-D), glow discharge (D-I) and arc discharge (I-K). A-B represents non-self-sustaining discharge and collection of spontaneously- generated ions. B-D is the Townsend region, where the cascade multiplication of carriers takes place. D-E is the transition to a glow discharge, breakdown of the gas. E-G represents transition to a normal glow; in the regions around G, voltage is nearly constant for varying current. The region G-I represents abnormal glow, as current density rises. I-J represents transition to an arc discharge.

Plasma discharge (which typically initiates at region D in the graph of Figure 1) is the most widely referred type of electrical discharge in the medical literature. Although potentially effective in ablating or heating tissues, plasma discharge is difficult to control due to its use of high currents and generation of high temperature that can harm healthy tissues. Because of high pressure, discharge ignition at atmospheric conditions requires high voltage and can arouse high current density. The gas temperature in active plasma volume increases up to several thousand degrees. By such treatment, tissue is over heated (hyperthermia) and partially evaporated. As such plasma discharge is typically used in surgery as plasma scalpel and for blood coagulation.

To avoid thermal damage, plasma discharge current can be limited by placing the treated tissue slightly away from the active plasma source as in the case of "indirect" plasma treatment. Alternative approaches utilize short voltage pulsing [Ayan et al. "Nanosecond-pulsed uniform dielectric -barrier discharge. IEEE Trans. Plasma Set, Vol. 36, pp. 504-50 (2008)] and a dielectric barrier (otherwise called 'insulator') that drastically reduces electric current through the tissue. Devices using the latter are so- called "dielectric barrier discharges (DBD)" devices [Bibinov et al. Basics and Biomedical Applications of Dielectric Barrier Discharge (DBD)"; Biomedical Engineering, Trends in Materials Science, pp. 123-150, (2011), ISBN 978-953-307- 513-6)] which are useful for "direct" treatment of living tissue.

While reducing the present invention to practice, the present inventors have devised a system which is capable of generating a discharge signal capable of initiating cascade multiplication of electrons and an electromagnetic wave of specific frequency at or near the tissue treated.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided a system for treating tissue comprising: (a) a signal generator for generating an electrical signal; and (b) a discharge head for converting the electrical signal to a discharge signal capable of initiating an electron gradient with respect to the tissue, the electron gradient being capable of generating a steadily increasing self-terminating electrical current at a substantially stable electrical potential between the discharge head and the tissue.

According to further features in preferred embodiments of the invention described below, the signal generator is configured for generating a signal having an electrical potential of 1-20 KV and a frequency of 50 KHz - 10 GHz.

According to still further features in the described preferred embodiments the discharge signal has an initial electron density of 10 9 -1012 cm -^"3. According to still further features in the described preferred embodiments the tissue is skin.

According to still further features in the described preferred embodiments the system is configured for treatment of a skin pathology or infection, including, for example, skin cancer, skin warts and the like.

According to still further features in the described preferred embodiments a discharge surface of the discharge head has an area selected from a range of 1-400 mm .

According to still further features in the described preferred embodiments the system further comprises a gas source for providing a gas from the discharge head.

According to still further features in the described preferred embodiments the system further comprises a controller for controlling gas pressure from the discharge head.

According to still further features in the described preferred embodiments the type of gas and the pressure affect the electron gradient.

According to still further features in the described preferred embodiments the gas is selected from the group consisting of Ozone, Hydrogen gas, Iodine gas, Chlorine gas, Hydrogen monoxide and ambient air.

According to still further features in the described preferred embodiments the system further comprises an element for modulating a temperature of the electrode.

According to another aspect of the present invention there is provided method of treating a tissue of a subject comprising: (a) generating an electrical signal; (b) converting the electrical signal into a discharge signal at or near the tissue, such that the discharge signal initiates an electron gradient being capable of generating a steadily increasing self-terminating electrical current at a substantially stable electrical potential at or near the tissue; and (c) optionally repeating (a)-(b) one or more times, thereby treating the tissue.

According to still further features in the described preferred embodiments the electrical signal is converted into a discharge signal via a discharge head having at least one electrode grounded by the tissue.

According to still further features in the described preferred embodiments the method further comprises administering a gas from the discharge head during or following step (a). According to still further features in the described preferred embodiments the tissue is a hair shaft and further wherein the discharge head is configured for applying the discharge signal to the hair shaft.

According to still further features in the described preferred embodiments the discharge signal includes an electromagnetic wave tuned by the signal generator for propagating through the hair shaft.

According to still further features in the described preferred embodiments the electrical current is in the range of 1-10 micro-amperes.

According to still further features in the described preferred embodiments the discharge head includes at least one electrode characterized by a conductivity range of 10⁴ to 10⁹ ohms.

According to still further features in the described preferred embodiments the tissue is a hair shaft and the electrical current maximizes at 4-6 microamperes.

According to still further features in the described preferred embodiments the electrical signal is 10-20 KV, and the discharge signal is generated by a discharge head having a conductivity of 10 5 -107 ohm.

According to still further features in the described preferred embodiments the discharge signal also generates an electromagnetic wave tuned for propagation through the hair shaft.

According to still further features in the described preferred embodiments the electromagnetic wave is in frequency of 9-11 MHz.

According to still further features in the described preferred embodiments the tissue is skin and the electrical current maximizes at 9-11 microamperes.

According to still further features in the described preferred embodiments the electrical signal is 5 KV, and the discharge signal is generated by a discharge head having a conductivity of 10 8 -1010 ohms.

According to still further features in the described preferred embodiments the discharge signal also generates an electromagnetic wave tuned for propagation through the skin.

According to still further features in the described preferred embodiments the electromagnetic wave is in frequency of 0.01-3 GHz. According to still further features in the described preferred embodiments the tissue is microorganism- infected tissue and the electrical current maximizes at 9-11 microamperes.

According to still further features in the described preferred embodiments the electrical signal is 3-6 KV, and the discharge signal is generated by a discharge head having a conductivity of 10⁴ to 10⁹ ohms.

According to still further features in the described preferred embodiments the discharge signal also generates an electromagnetic wave tuned for propagation through the microorganism.

According to still further features in the described preferred embodiments the microorganism is a fungus and the tissue is skin or nail tissue.

According to still further features in the described preferred embodiments the method further comprises administering a gas to the microorganism- infected tissue during or following step (a).

According to still further features in the described preferred embodiments the electromagnetic wave is in frequency of 50 KHz.

According to another aspect of the present invention there is provided a discharge head for treatment of tissue comprising: (a) a first electrode disposed within a housing and being connectable to a power source; (b) a second electrode disposed within the housing and being spaced apart from the first electrode so as to form a detectable spark gap, wherein a distance of the spark gap is adjustable.

According to still further features in the described preferred embodiments the discharge head further comprises an optical sensor for sensing light emitted by a spark formed in the spark gap.

According to still further features in the described preferred embodiments the discharge head further comprises a control circuit for processing the light sensed by the optical sensor and for modifying a gap of the spark gap according to a frequency of the light. The present invention successfully addresses the shortcomings of the presently known configurations by providing a system configured for generating an electrical discharge signal at or near a tissue thereby treating it while minimizing the effects on surrounding healthy tissue.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

In the drawings:

FIG. 1 is a prior art graph showing voltage versus current characteristics for neon gas at 1 Torr pressure between flat electrodes spaced 50 cm apart.

FIG. 2 illustrates one embodiment of the present system.

FIG. 3 illustrates one embodiment of a discharge head suitable for use in a system configured for dermatological or aesthetic treatment of skin.

FIG. 4 schematically illustrates one embodiment of an electrical signal generator suitable for use with the present invention.

FIG. 5 illustrates a gas generator suitable for use with the present system.

FIG. 6 illustrates an ozone generator suitable for use with the present system. FIGs. 7A-D are oscilloscope traces of a generated electrical signal (FIGs. 7A, 7C) and its corresponding discharge wave (FIGs. 7B, 7D) in skin.

FIG. 8 schematically illustrates one embodiment of a discharge head constructed in accordance with the teachings of the present invention.

FIG. 9 schematically illustrates one embodiment of a system used for signal generation and testing.

FIG. 10A schematically illustrates the electrical circuitry of the system of

FIG. 9.

FIG. 10B schematically illustrates the electrical circuitry of a high voltage pulse sensor.

FIG. IOC illustrates an optical sensor circuit for processing the optical signal collected by the discharge head of FIG. 8.

FIG. 11 is oscilloscope images of an output waveform from oscillator II (Upper signal) and a modulated frequency that was recorded at the high voltage transformer output (lower signal).

FIG. 12 is an oscilloscope image of a high frequency, high voltage signal at the transformer secondary output without modulation.

FIG. 13 is an oscilloscope image of a high frequency signal at the high voltage transformer output.

FIG. 14 schematically illustrates a system for current measurements.

FIG. 15 is an oscilloscope image of a current pulse and the recorded data of the pulse at standard input pulse.

FIG. 16 is an oscilloscope image of a standard input voltage pulse and the recorded data of the pulse.

FIG. 17 is an oscilloscope image of a standard input voltage pulse and the recorded data of the pulse.

FIG. 18 schematically illustrates the pulse measurements circuit.

FIG. 19 is an oscilloscope image of an output signal from the internal modulating oscillator.

FIG. 20 is an oscilloscope image of a modulated pulse following mixing and high voltage multiplication. FIGs. 21A-B are light emission spectra of ambient air for a single frequency (FIG. 21A) and a modulated pulse (FIG. 21B), recorded for metallic electrodes.

FIG. 22 is a light emission spectrum of ambient air with no control of power or frequency.

FIG. 23 is a light emission spectrum of forced air with ozone for a modulated signal.

FIG. 24 is a light emission spectrum for a modulated signal at full power conditions at a 220 ohm resistor simulating living tissue.

FIG. 25 is a light emission spectrum of ambient air recorded at minimum power with no observed visible light emission or current.

FIG. 26 illustrates the results of Mulluscum treatment by Liquid Nitrogen (Nitrogen), Commercial Electro-Surgery (Commercial ES) and the present system (Medischarge 1, 2 and 3). DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is of a system which can be used to treat tissues or microorganism-infected tissue thereof. Specifically, the present invention can be used to subject tissues or micro-organisms to a discharge signal characterized by a self propagating cascade of electrons and an electromagnetic wave tuned for tissue penetration.

The principles and operation of the present invention may be better understood with reference to the drawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

Use of electrical discharge typically in the form of plasma discharge has been described in context of medical applications. Plasma discharge can be hard to control and direct since it employs a high current flow and electron density with heated gas or external heating and thus produces high temperatures which may damage healthy tissues surrounding the treatment site.

In order to traverse the limitations of prior art electrical discharge systems, the present inventors devised a system which is configured for generating an electrical signal that harnesses the Townsend Electric Discharge effect and in addition utilizes active gas flow and optionally mist jet in a condensed matter state in order to maximize a therapeutic or aesthetic effect on tissues such as skin while minimizing deleterious effects in healthy tissues. As is described in the Background of the Invention section above, the Townsend discharge is primarily characterized by a very low current (in the range of microamperes) and a low current density. Following discharge, the current gradually dissipates and self-terminates due to a change in the electrical conductivity of the treated tissue as a result of an apparent molecular transformation of the treated biological tissue. That insures a short duration of treatment with minimal or no damage to healthy tissues.

Thus, according to one aspect of the present invention there is provided a system for treating tissue. As used herein, the term "tissue" relates to any tissue of the body including living and non-living tissue. Examples of tissue include but are not limited to skin, bone, muscle, hair, nail, nerves, and the like.

As used herein, the term "treatment" relates to therapeutic or aesthetic treatment. Therapeutic treatment can be directed to pathological tissue (e.g. tumors), infected tissue (e.g. fungal or bacterial- infected tissue, Seborrheic keratosis, viral warts) or the like. Aesthetic treatment can be directed to skin (e.g. wrinkles, cellulite, acne, Lipomatis), hair (e.g. depilation, Fuliculitis, ingrown hair) or the like.

The system of the present invention includes a signal generator for generating an electrical signal and a discharge head for converting the electrical signal to a discharge signal. The parameters of the electrical signal and the discharge head are configured such that the discharge signal is capable of initiating an electron gradient capable of generating a steadily increasing self-terminating electrical current at a substantially stable electrical potential between the discharge head and the treated tissue.

In order to generate an electrical signal of appropriate parameters, the signal generator includes a power controller, voltage multiplier and frequency modulator which together are capable of generating an electrical potential of 1-20 KV and a frequency of 50 KHz - 10 GHz and a user interface for enabling a user to select an appropriate electrical potential and frequency. This ensures that a discharge signal resulting from the electrical signal has an initial electron density of 10 9 -1012 cm -^"3 and thus propagates (provided an appropriate medium) via an electron cascade supported by the Townsend electrical discharge effect. A second effect of the electrical signal is generation of electromagnetic waves that can be tuned (frequency and amplitude) for penetration into specific tissue. Townsend discharge and electromagnetic wave propagation are described in greater detail herein below.

The signal generator is electrically wired to the discharge head which serves as an anode and includes one or more electrodes.

The system of the present invention further includes a ground electrode (cathode) which is configured for attachment to the tissue at the treatment site or a region displaced there from.

As is mentioned hereinabove, the present system generates a discharge signal which is selected for generating a Townsend discharge effect.

The Townsend discharge is a gas ionization process where an initial and very small amount of free electrons, accelerated by a sufficiently strong electric field, give rise to electrical conduction through a gas by avalanche multiplication (cascade). When the number of free charges drops or the electric field weakens, the phenomena ceases. It is a process characterized by very low current densities, while the applied voltages are almost constant; the electrical model is of the capacitor. Townsend found that the current I flowing into the capacitor depends on the electric field between the plates in such a way that gas ions seems to multiply as they moved between them. He observed currents varying over ten or more orders of magnitude while the applied voltage was virtually constant. The experimental data obtained from his experiments are described by the following formula:

J__ _e<*nd Where:

• I is the current flowing in the device,

• 7₀ is the current generated at the cathode surface,

• e is the Euler number,

· On is the first Townsend ionization coefficient, expressing the number of ion pairs generated per unit length by a negative ion moving from cathode to anode

• is the distance between the plates of the device.

As is mentioned hereinabove, the discharge signal can also include an electromagnetic wave component. The frequency of the electromagnetic wave is generated by pulsing the high voltage signal and further modulating it. The vibrational frequency of the discharge signal interacts with the treated tissue and penetrates to a specific tissue depth. The electromagnetic signal is modulated to an effective appropriate frequency, depending on the density and depth of the treated tissue as well as its biochemical structure. This enhances both the effect of the electrical discharge signal and the interaction of the support gas which is supplied to the treated region.

To generate a Townsend discharge between the discharge head and the tissue, the discharge head must either directly contact the tissue or be displaced therefrom via a medium capable of generating and supporting a Townsend discharge.

Thus, according to one preferred embodiment of the present invention, the system also includes a gas source.

The gas support is not essential, ambient air present between the discharge head and tissue can also support formation and propagation of the discharge signal. However, the gas can also provide a medical function (ozone, for example is an effective biocide) as well as contribute to the effectiveness of the discharge signal by enhancing ionization and penetration into the tissue. The gas can also stabilize the electromagnetic wave propagation and contribute to its effect on the tissue.

Such a gas source can be a compressed gas source or a gas generator (for generating a gas or gas mixture) connected via fluid lines to the discharge end of the discharge head. Examples of gasses that can be provided from the gas source include, but are not limited to Ozone, Hydrogen gas, Iodine gas, Chlorine gas, Hydrogen monoxide or any other gas which can enhance electrical conductivity and reactivity with the treated tissues.

To further enhance discharge signal generation and propagation, the present system can also include a mist generator which can optionally form a part of the gas generator. The mist generator can controls the permeability, vapor pressure, heat and electricity conductance of the gas.

Thus, in a preferred configuration of the present system, the discharge head simultaneously applies a discharge signal and a gas or gas mixture (and optionally a mist) to generate and support a self -propagating cascade of electrons. The interaction of the discharge signal and gas with the tissue provides a two prong effect, the gas cleans and sterilizes (by oxidizing the treated area) the tissue and further creates a route (in the tissue) through which the discharge signal traverses through the tissue while the electron and optionally electromagnetic wave components of the discharge signal propagate through the tissue to react with the molecules by releasing the discharge energy at the appropriate depth. The frequency of the electromagnetic wave is determined by modulating both frequency and amplitude and set for resonance condition in a given structure and its depth on or under the treated tissue, thus tuning the resonance energy to the micro- or nano- cavity formed or present in the tissue.

The electrical signal can be tuned over a range of frequencies and power in order to match the parameters of the discharge signal (electron density and electromagnetic wave frequency and amplitude) to a particular tissue and/or micro-organism. Such tuning can be effected by the physical properties of the support gas (heat and electrical conductivity, permeability). The electromagnetic wave(s) is tuned to propagate through an existing physical cavity (e.g. spinal of a Hair structure) or through a cavity created by the forced gas flow during the initial discharge signal (e.g. in Acne or Warts). Such cavities provide a path which has a diameter in the range of nano- to micro- meters.

Thus, one aspect of the present invention provides a non-invasive system for treating tissue via a discharge signal that is robust and can be tuned for penetrating any tissue with any constitution, pigmentation and depth. The treated tissues serve as a ground for conducting the discharge signal current, while also simultaneously serving as a cavity through which the electromagnetic waves propagate into the treated tissues. Referring now to the drawings, Figures 2-6 illustrate the present system which is referred to herein as system 10.

As shown in Figure 2, system 10 includes signal generator 12 which is connected to discharge head 14 (also referred to herein as applicator) and ground electrode 16 via wires 18 and 20 (respectively). Signal generator 12 is connected to a power source 15 (e.g. AC outlet) through a power regulator 13.

Signal generator 12, which is shown in greater detail in Figure 4, includes a signal generator and modulator 17 which includes a rectangular wave generator with variable duty cycle and variable amplitude, a mixer and current control limiter 19, a high voltage generator 21, a voltage multiplier 23 and current limiter 25.

Wires 18 and 20 include a conductor material such as a flexible Coax wire having a conductivity of less than 10 ohm and an insulator fabricated from any material with insulation greater than 50 KV. Discharge head 14 (also shown in Figure 3) includes a housing 22 fabricated from Quartz, Teflon, Metallic hollow needle and shaped as a hollow tube having a length of 5-10 cm and a diameter of 2-5mm. Depending on the use, housing 22 can alternatively be fabricated as an array of tubes. For example, a discharge head suitable for hair removal can be shaped as a plow for maximizing contact to the hair shaft. One or more electrodes 24 are disposed within housing 22 and arranged as a matrix. Electrode(s) 24 can be fabricated from Stainless Steel, Tungsten; BDD (Boron Doped Diamond), Electrodes 24 of discharge head 14 has a discharge surface of 1-400 mm² and a conductivity of 10⁴ to 10⁹ ohms.

Discharge head 14 and ground electrode 16 can be configured as a fine metallic plow shape, disc or any shape that will deliver the discharge spark to specific tissue/location and eliminate discharge in an undesired one.

Ground electrode 16 can further include a mechanism for attachment to the tissue which incorporates an adhesive grounding pad or straps. Ground electrode 16 can also incorporate a manual or electric shaving head for shaving hair (in case of hair removal).

System can further include a gas source 30 which can include a compressed gas or be configured as a combined gas generator and a liquid source 33 (collectively 39 - shown in detail in Figure 5). Gas source is connected to a gas and liquid mixer 39 which supplies the gas and liquid as a mist which is communicated to discharge head 14 through tubing 37. Gas and Liquid mixer 39 generates a specific mixture of gas and liquid for each specific tissue treated. For example, in the case of hair treatment, such a mixture includes organometallic gases and polymeric silicon.

System 10 can further include an ozone generator 40 (shown in detail in Figure 6) for providing ozone gas to the treated area. As shown in Figure 6, ozone generator 40 may include a high voltage generator 41, a voltage multiplier unit 43, a compressed air source 45 with air filters and a corona unit 47.

System 10 further includes a control unit and interface 35 for enabling a user to set and control the signal and gas-mist mixture provided to discharge head 14.

In order to more precisely control the electrical discharge process, the present inventors have devised a discharge head which enables an operator to monitor the discharge process and control (via open or closed loop) the parameters governing the discharge at the tissue. One embodiment of such a discharge head which is referred to herein as discharge head 50, is shown in Figure 8.

Discharge head 50 includes a housing 52, at least a portion of which is preferably formed from a transparent tube (e.g. glass). Housing 52 has a diameter of 10-20 mm (preferably 15 mm) and a length of 10-20 cm (preferably 15 cm). A smaller diameter tube 54 (preferably fabricated from a polymer) is positioned within proximal portion 56 of housing 52, and serves as a gas source tube (connectable to a gas source).

A high voltage connection cable 58 is connected to a proximal electrode assembly 60 which is fitted within opening 62 of tube 54. Electrode assembly 60 has a needle like (beveled/pointed) distal end 64 which is spaced apart (gap 70) from a proximal end 66 (of similar configuration) of distal electrode assembly 68 by 0.5-3 mm. Gap 70 can be adjusted by moving electrode assembly 60 and/or 68 and a spark formed therein can be viewed by the operator (through transparent housing 52). Distal end 72 of electrode assembly 68 is nestled within a distal end 74 of housing 52. Distal end 74 is configured for contacting a tissue (e.g. skin) and maintaining distal end 72 of electrode assembly 68 spaced apart from the tissue (1-3 mm).

Distal end 74 of housing 52 is placed in contact with tissue, and a high voltage current (1-10 KV) is supplied to proximal electrode assembly 60 in order to provide an electrical pulse to the tissue. Adjustment of the electrical pulse can be effected by varying gap 70 or the distance of distal end 72 of electrode assembly 68 from distal end 74 of housing 52 using, for example, mechanism 75 (e.g. 0-3 mm). Since the spark formed at gap 70 mirrors the spark formed at the tissue, the spark at gap 70 enables the operator to determine if tissue spark parameters are correct for the specific treatment sought.

For example, in treatment of skin wart, a spark at gap 70 having 0.5-1.0 mm, emitting light at the range of 200-900 nm indicates current of 10 microampere which are the correct conditions for treatment according to the teachings of the present invention. If prior to, or during, treatment such a spark is not observed (e.g. a spark having yellowish color is evident), then an operator can adjust gap 70 until correct spark parameters are visible at gap 70. Once correct spark parameters are observed they are maintained throughout treatment until self termination of current as described above.

Monitoring of spark in gap 70 can be done by the operator and gap 70 adjusted manually thereby. Alternatively, such monitoring can be effected using an optical sensor 82 which can provide the operator within a sensor reading (spark spectral signature). Such a reading can be used by the operator to manually adjust gap 70 (open loop) or it can be used to operate actuators for automatically adjusting gap 70 (closed loop).

Optical sensor 82 is mounted at gap 70 to collect light emitted by the spark. The light signal is communicated through a fiber optic 84 to the control circuit (Figure 10c) that includes the excitation frequency data (down to the spectrum level). The control circuit can then determine spark parameters from the light signal frequency and adjust gap 70 as needed. Alternatively, the optical readings from optical sensor 82 can be used by an operator to manually set gap 70. Further, the optical signal may be synchronized with the discharge signal (by triggering emitted light collection) to provide additional data on treatment.

As is mentioned hereinabove, system 10 of the present invention can be used in aesthetic or therapeutic treatment of a body tissue of a subject, such as a mammal, preferably human.

System 10 enables a non-invasive, reliable treatment with no significant pain or discomfort while minimizing deleterious effects to non-treated tissues.

System 10 of the present invention can be used in hair removal, treatment of ingrown hair, eradication of microorganisms such as bacteria and Fungus, removal or reduction of skin growth such as moles and warts, treatment of acne, psoriasis, eczemas, dermatitis, ulcerous injuries and scleroderma.

For example, the present invention can be used to treat dental tissues (e.g. chronic gingivitis), nerves, gland tissue (e.g. to stimulate secretion from salivary glands), to deliver drugs (e.g. analgesics) and essential elements (e.g. iron, calcium, etc.) to specific tissues, to remove pathological tissue, by tuning the appropriate parameters (Supporting gas, Frequency, Ion stream and Discharge values).

Thus, according to another aspect of the present invention there is provided a method of treating a tissue of a subject. The method is effected by utilizing the present system under electrical signal parameters and gas/mist mixture suited to the tissue treated.

The following describes use of the present invention in treating several preferred disorders/pathologies . Hair removal

The present system can be used for hair removal. System 10 having a discharge head 14 configured for attachment to a human hair is calibrated for hair removal as follows.

Signal frequency and power is initially selected and applied. The system then self-tune the wave form, power, and frequency as well as gas/mist values based on a comparison between the theoretical discharges values (of the initial signal) and the actual signal discharged. For example, an electrical signal having a saw tooth signal with 0-12 V to control the amplitude of the discharge signal can be used. It is selected and adjusted automatically by swipe ramping of the voltage until a discharge signal is observed by the naked eye. The initial signal is then modulated and locked-in for the desired Townsend discharge effect in the gas mixture selected.

Following calibration of the system, the area to be treated is first shaved leaving about 0.5 mm of hair length. Next, ozone flow of less than 10^" ppm is introduced simultaneously with the modulated discharge signal. A stable condition is tuned using the control circuit by comparing the power, frequency and waveform parameters during the first seconds and followed by scanning the entire region of interest for hair removal. Typical signal parameters for hair removal include a voltage range of 1-10 KV, a frequency of 5 KHz up to 100 MHz and current of less than 10 microampere. As soon as the process is completed the discharge signal fades spontaneously, due to a significant change in the electrical conductance of the treated area. The hair functions as the main electric charge conductor (enhanced by the gas/mist) since the tissues surrounding it are more resistant to electrical conduction. In addition to conducting the discharge signal, an electromagnetic wave (discharge pulse) is longitudinally propagated within the core of the hair (spinal and papilla), releasing the energy of the pulse to the dermal papilla cavity which resides in the dermis. The hair also functions in extracting excess heat that might be created during the process, and in effect functions like a cooling element or a "chimney". Following discharge signal dissipation, the treated hair exhibits significant reduction in electrical conductance, becoming almost an electrical insulator, and no further electrical discharge can be propagated there through.

Without being bound to a theory, the present inventors postulate that the discharge signal penetrates the skin and effects the dormant hair cells at the bottom of the dermal papilla; this hypothesis is supported by the fact that no new hair growth could be observed at the treated region for a few months.

Viral Wart Removal

The present system can also be used to remove various types of warts (e.g. viral warts). Applying a discharge signal with or without ozone to warts can completely eradicate the pathogen and restore the tissue to a healthy state. Furthermore, Ozone produces a biocide effect which can enhance treatment of the infection. In the case of viral warts, Voltage set up will be at a range of 1-20 KV, a primary frequency of 0.4-20 KHz, a secondary frequency of 10 MHz -100MHz and a current of 1-10 micro-ampere with a flow of Ozone (less than 10^" ppm).

Acne

The present system can also be used to treat acne. Based on the severity and shape of the acne, the system can generate a discharge signal which creates artificial micro- and nano- meter cavities in acne tissue. These cavities can concentrate and channel the discharge pulses, as well as gas (e.g. ozone) and other treatment agents (e.g. polymeric silicon) used in the treatment to thereby disinfect and treat the acne tissue.

Acne inflamed tissue can be treated with a system that provides ozone (less than 10^" ppm) or another gas (e.g. Iodine), and a discharge signal having a modulated frequency of 0.5-100 KHz. Treatment is directed into the infected sebum down to the sebaceous glad. As a result, the surface layer is treated and the route from the infected tissues to the surface of the skin is disinfected.

Fungal Infections

The present system can also be used to treat fungal infections. Applying ozone and a discharge signal to fungal infected tissues completely eradicates the infection. Ozone produces a biocide effect which is enhanced by the electron flux and electromagnetic wave generated by the discharge head.

Furthermore, the discharge effect will excite molecular constituents of the fungus exposing excited electrons to electromagnetic field. The phenomenon can cause transformation of the Fungus molecular structure and thus can contribute to the biocide effect.

In the case of a nail fungus, a double modulated electromagnetic signal is mandatory in order to pass the signal through the nail. An initial Voltage set up will be at a range of 1-20 KV, a primary frequency of 0.4-20 KHz, a secondary frequency of 10 MHz -10 GHz and a current of 1-10 micro-ampere with a high flow of Ozone (less than 10^"2 ppm). The present system can be used to treat several other indications by applying signals of high voltage at the range 1-10 KV and frequency range of 40 KHz up to 500 MHz in conjunction of steady flow of ozone and/or additional gases. A non- comprehensive list of indications that can be treated using the present invention is provided below. Skin Neoplasms

Skin neoplasms (also known as "skin cancer") are skin growths with differing causes and varying degrees of malignancy. The three most common malignant skin cancers are basal cell carcinoma, squamous cell carcinoma, and melanoma.

Present treatment approaches depend on the type of cancer, location of the cancer, age of the patient, and whether the cancer is primary or a recurrence. For a small basal cell cancer in a young person, the treatment with the best cure rate (Mohs surgery or CCPDMA) might be indicated. In the case of an elderly frail man with multiple complicating medical problems, a difficult to excise basal cell cancer might warrant radiation therapy (slightly lower cure rate) or no treatment at all. Topical chemotherapy might be indicated for large superficial basal cell carcinoma for good cosmetic outcome, whereas it might be inadequate for invasive nodular basal cell carcinoma or invasive squamous cell carcinoma. In general, melanoma is poorly responsive to radiation or chemotherapy.

For low-risk disease, radiation therapy (external beam radiotherapy or brachytherapy), topical chemotherapy (imiquimod or 5-fluorouracil) and cryotherapy (freezing the cancer off) can provide adequate control of the disease; both, however, may have lower overall cure rates than certain type of surgery. Other modalities of treatment such as photodynamic therapy, topical chemotherapy, electrodesiccation and curettage can be found in the discussions of basal cell carcinoma and squamous cell carcinoma.

Cutaneous Leishmaniasis

Cutaneous Leishmaniasis the most common form of leishmaniasis. It is a skin infection caused by a single-celled parasite that is transmitted by sand fly bites. A single optimal treatment of cutaneous leishmaniasis is not currently available. Treatments that work for one species of leishmania may not work for another. Ideally, every effort should be made to establish the species of leishmania by molecular techniques (PCR) prior to starting treatment. Unfortunately, leishmaniasis is an orphan disease, and almost all the current treatment options are toxic with significant side-effects. Corneal Infections

Damaged to the cornea from trauma of any type can lead to a corneal ulcer and may be accompanied by bacterial, viral or fungal infection of the cornea (Keratitis).

Keratitis can cause a painful inflammation with a discharge, which if not treated quickly and appropriately, can lead to corneal erosion, corneal ulceration and corneal scarring. Corneal scarring results in a loss of corneal transparency and can require a corneal transplant in order to restore vision.

Treatment for corneal ulcers and infections depends on the cause. If the exact cause is not known, patients may start treatment with antibiotic drops that work against several types of bacteria. Once the exact cause is known, drops that treat bacteria, herpes, other viruses, or a fungus are prescribed. Corticosteroid eye drops may be used to reduce swelling and inflammation in certain conditions.

The present system can be used as first line therapy to treat the corneal ulcer and reduce the chances of corneal infection. The present system can also be used to treat corneal infections with or without adjunct antibiotic, antiviral or anti fungal drug therapy.

Dental Cavities

Tooth decay is one of the most common of all disorders, second only to the common cold. Bacteria that are normally present in the mouth convert food (especially sugar and starch) into acids. Bacteria, acid, food debris, and saliva combine in the mouth to form a sticky substance called plaque that adheres to the teeth. The acids in plaque dissolve the enamel surface of the tooth and create holes (cavities) in the tooth.

The Present system can also be used in a non-invasive manner to treat gum infection eliminating viruses and bacteria without pain.

Skin Rejuvenation

Plasma skin regeneration (PSR) is an FDA approved skin treatment approach introduced to US markets in 2005 and European markets in 2006. PSR devices minimally damage the skin tissue in a controlled manner and are quite effective at stimulating skin regeneration thus promoting non-wounding skin rejuvenation in which superficial layers of skin are shed in the post-treatment phase. Due to its heat, a local anesthetic is required for the treatment and a systemic anesthetic, administered orally, is recommended.

The system of the present invention can be advantageous over plasma in skin regeneration in that no pain or heat are sensed during the treatment.

Wound Healing

Acute or chronic wounds such as pressure ulcers, diabetic foot and leg ulcers can also be treated using the system of the present invention.

Thus, the present invention provides a system which can be used for aesthetic or therapeutic treatment of tissues such as skin, hair and the like. The present technology harnesses the Townsend discharge effect to conduct an electrical discharge into the region of interest, while simultaneously exposing the treated region to a gas or gas mixture which enhances the effect of the discharge signal and provides additional therapeutic effects. The present system and treatment are non-invasive and can be used with a wide range of tissue types and pigmentation levels (e.g. in hair and skin). The treatment procedure is straightforward and easy to execute and is safe. As shown in Examples 1 and 6, preliminary results obtained using the present system and treatment approach demonstrate that treatment is effective, rapid (several minutes) and the results are stable for prolonged periods (at least months).

As used herein the term "about" refers to ± 10 %.

Additional objects, advantages, and novel features of the present invention will become apparent to one ordinarily skilled in the art upon examination of the following examples, which are not intended to be limiting. Additionally, each of the various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below finds experimental support in the following examples. EXAMPLES

Reference is now made to the following examples, which together with the above descriptions, illustrates the invention in a non limiting fashion. EXAMPLE 1

Hair Removal

An area of 20 mm by 20 mm was shaved leaving hair about 0.5 mm in length. A reference area having an identical size and hair growth was shaved and used as a control. An Ozone flow of 0.05 cfm was introduced simultaneously with a modulated signal of 5 KV and 5 microamperes; the skin layer surrounding the treated area was grounded.

A stable signal was tuned during the first seconds by applying an Ozone flow over the tissue and increasing the voltage until the appearance of the discharge signal while maintaining the current at about 5 microamperes. The discharge head was moved over the treated region thereby exposing the treated region to the discharge signal. The discharge signal faded spontaneously and the treated hair exhibited a significant reduction in electrical conductance; no further electrical discharge could be driven into the skin and the hair. No burns were observed at the site of treatment.

Five months post treatment; the control region exhibited normal hair growth, while the treated region showed no new hair growth and remained identical to its appearance following shaving and treatment.

EXAMPLE 2

Discharge signal in Skin

The waveforms of an input and discharge signals of the present system were recorded using an oscilloscope (UNTT UT2025C). Voltage of 4 KV was applied to the electrodes at frequency of 58 KHz. Low and high gain electrical signals were generated by the system of the present invention and used to form a discharge signal at the discharge head electrode which was disposed 2 mm from the skin of a subject. Figures 7A-D illustrate the basic input signal while the ground electrode was floating (high gain at Figure 7A and low gain at Figure 7B) and following discharge (high gain at Figure 7C and low gain at Figure 7D). As shown by these Figures, the maximum peak voltage amplitude and the signal frequency of the basic input signal decreased due to discharge at the tissue. Moreover the basic signal decayed to a modulated signal with two identical maxima, as postulated by the present inventors. EXAMPLE 3

System Setup and Signal Generation

A system including a power generator, discharge head (also referred to herein as applicator) and gas source was assembled and tested for signal generation. Figure 9 schematically illustrates the system. The applicator (discharge head) includes a discharge electrode and tubing to support gas flow. Figures 10A-B illustrates in detail an electrical circuit that generates the electromagnetic pulse and current flow in the circuit (Figure 10A) and the schematic circuit of a high voltage pulse sensor (Figure 10B).

The main power supply is connected to a main electric power line (220 V, AC). Next, a variable DC output of 6-12 V is transformed from the main input power to provide +VCC to the sub system circuits (Oscillator I, Oscillator II, Mixer amplifier, Power amplifier, Coil high voltage transformer).

Oscillator I has a power input (+Vcc), at the output it exhibits a carrier frequency range of 90-110 KHz wave with amplitude of 5-12 Vp. This signal is the input to the Mixer & Amplifier unit (with an operation power -i-Vcc), an additional input is introduced from Oscillator II, providing frequency modulation at the range of 0-100 KHz with a square waveform and an amplitude at the range of 6-12 Vp, shown in Figure 11. A third frequency may be incorporated to the mixer from an external signal generator (Tektronix AFG 3102), this provides an optional application of high frequency (up to 100 MHz). The output from the mixer amplifier unit is chopped to a duty cycle of about one third of the input frequency and variable amplitude at the range of 5-12 V. This output signal is an input into the power amplifier, resulting at an output of 20-30 V supplied to the primary coil of the high voltage transformer. The transformer secondary coil provides an output of about 800 Vpp. This signal is subjected to the voltage multiplier, with an output up to 8000 Vpp for the final modulated signal that is supplied to the applicator (Figure 11); the signal prior modulation is shown in Figure 12. The resulting pulse (Figure 13) has time duration of about 60 ns, providing the required high frequency signal necessary for treating tissue (at specific frequency and excitory energy).

The voltage multiplier is activated on the high voltage signal to achieve the actual signal that penetrates the tissue. This multiplication is also employed to control the signal energy by adjusting the amplitude via the capacitance profile of discharge. When the applicator tip is positioned close to living tissue (in the non contact mode, at distance of 1-3 mm), it closes the electrical circuit and an electrical discharge is generated with low current at the microampere level (measured separately with the current analysis circuit described below with respect to Figures 14 and 15).

Moreover, the gas support mixer provides the appropriate gas supply in conjunction with the applicator electrode in order to stabilize the ionization process, sanitize the treated tissue when required or control the therapeutic procedure with the incorporation of drugs into the supplied gas mixture. Circuit safety is achieved by shorting the circuit when accidental direct contact between the electrode tip and tissue occurs. This is attributed to an apparent saturation at the high voltage coil which changes the oscillation conditions, thus terminating the main oscillator operation. Alternatively, while a direct connection is evident, no discharge can be activated and the high voltage is effectively grounded by the tissue. In addition, a dielectric barrier regulator can be used to completely terminate the final high voltage signal input to the electrode.

EXAMPLE 4

Frequency and Current Measurement

The following describes the Townsend current and frequencies provided by the applicator of the present system when used for dermatology and aesthetics treatments.

Figure 14 illustrates a set up used for current measurements. The current measurement probe is a Tektronics TCP 202 and the high voltage probe is an Agilent #10076B (100: 1, 250 MHz). An Agilent infiniivision MSO7104A (1 GHz, 4 GSa/s) oscilloscope was used to record the signals.

Figure 15 illustrates the signal recorded from a current probe located at point B in the schematic of Figure 14 (between the resistors). The peak current is 49 mA with a rise time of 8 ns and a width (FWHM) of 12 ns (the latter determines the effective energy of the pulse). It will be appreciated that this is not the current that flows through the ionized gas (ambient air). The actual current value that creates the Townsend effect at the microampere level is determined from light emission measurements of the ionized gas at the discharge conditions employed. A peak power of 765 V is measured at the output of the high voltage transformer, whereas, the final pulse is further multiplied by the voltage multiplication circuit. No apparent heat is involved with the pulse.

Single and double modulated signals

Figure 17 shows an applicator signal at maximum power recorded at a 1 ohm resistor positioned adjacent to a voltage divider (Figure 18). A pulse of 150 MHz and duration of 3 ns with rise time of 0.6 ns was recorded. Mixing of this pulse with a square waveform signal outputted by the modulation oscillator (Figure 15) results in a modulated pulse (Figure 16).

EXAMPLE 5

Pulse analysis by optical spectrum recording

A dedicated set-up was used to measure the light emission spectrum and the discharge intensity of gas ions generated by the present system. An Ocean Optics HR 2000 spectrum analyzer was used to record the optical signal resulted from the ionized air (sometimes mixed with ozone).

Figures 21A-B illustrate the reference light spectrum that was measured for maximum power between two metallic electrodes at the ambient air. The spectrum of Figure 21A shows the emission of a single frequency signal whereas the spectrum of Figure 21B shows the emission for a modulated pulse. The intensity units are represented as counts per second versus the wavelength in nanometers. Figure 22 shows a light spectrum emission of ambient air with no control of power or frequency. This is given as a reference to the controlled signals with a forced air with ozone flow shown in Figure 23 and additional spectrum of Figure 24 which was recorded against 220ohm resistor simulating live tissue.

The second experiment was carried out under minimum power conditions (2-5 KV and pulse width of 30-40 ns); the applicator was positioned in proximity to a 220 ohm resistor (simulating body tissue resistance) and no visible light emission could be observed by a naked eye. Figure 25 clearly illustrates that under such conditions some faint emission is still evident, this suggests that few atoms are still ionized to give rise to a very small current of 1-2 microamperes. However, no current flow was observed when the applicator tip was advanced towards the 220 ohm resistor. A minimal current was only detected in the live tissue at a much higher power of about 5 KV. This provides strong evidence that the parameters and system used generate a Townsend effect at the tissue.

EXAMPLE 6

Treatment of Mulluscum Contagiosum

Mulluscum viral warts were treated using the present system, liquid nitrogen or commercial Electro-Surgery system, the results are presented in Figure 26.

Liquid Nitrogen treatment left a significant scar, while treatment with the commercial Electro-Surgery device resulted in tissue ablation and some infection and left a faint scare 100 days post treatment. In contrast, treatment with the present system did not result in any ablation or heating of the tissue (Medischarge 1, 2, 3), the treated individual did not report any pain or a sensation of heat (the Nitrogen and Electro Surgery procedures induced pain). Gradual healing was observed over a course of 100 days, at the end of which, no significant damage or scarring to the treated skin region or surrounding skin regions were observed. More than 10 warts were treated using the present system showing good repeatability of results (three treatments are shown in Figure 26).

These experiments clearly show that the Townsend effect (self terminating process) can be achieved in tissue by employing an electromagnetic pulse under high voltage and very low threshold current through conductive ionized gas molecules (ambient air or other). By using a controllable applicator, a robust high voltage pulse that can be constantly maintained during treatment can be generated and driven into living tissue for the purpose of dermatological and/or aesthetic treatment, without ablating or heating the tissue and without causing any discomfort to the treated individual. It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub combination.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

WHAT IS CLAIMED IS:

1. A system for treating tissue comprising:

(a) a signal generator for generating an electrical signal; and

(b) a discharge head for converting said electrical signal to a discharge signal capable of initiating an electron gradient with respect to the tissue, said electron gradient being capable of generating a steadily increasing self-terminating electrical current at a substantially stable electrical potential between said discharge head and the tissue.

2. The system of claim 1, wherein said signal generator is configured for generating a signal having an electrical potential of 1-10 KV and a frequency of 50 KHz - 10 GHz.

3. The system of claim 1, wherein said discharge signal has an initial electron density of 10 9 -1012 cm -^"3.

4. The system of claim 1, wherein said tissue is skin.

5. The system of claim 1, wherein said discharge head is configured for treating a skin pathology or infection.

6. The system of claim 1, wherein said electrical current is in the range of 1- 10 micro-amperes.

7. The system of claim 3, wherein said discharge head includes at least one electrode characterized by a conductivity range of 10⁴ to 10⁹ ohms.

8. The system of claim 7, wherein a discharge surface of said discharge head has an area selected from a range of 1-400 mm .

9. The system of claim 1, further comprising a gas source for providing a gas from said discharge head.

10. The system of claim 9, further comprising a controller for controlling gas pressure from said discharge head.

11. The system of claim 10, wherein said type of gas and said pressure affect said electron gradient.

12. The system of claim 9, wherein said gas is selected from the group consisting of Ozone, Hydrogen gas, Iodine gas, Chlorine gas, a gaseous organometallic compound, Nitrogen Monoxide and ambient air.

13. The system of claim 1, further comprising an element for modulating a temperature of said electrode.

14. A method of treating a tissue of a subject comprising:

(a) generating an electrical signal;

(b) converting said electrical signal into a discharge signal at or near the tissue, such that said discharge signal initiates an electron gradient being capable of generating a steadily increasing self-terminating electrical current at a substantially stable electrical potential at or near the tissue; and

(c) optionally repeating (a)-(b) one or more times, thereby treating the tissue.

15. The method of claim 14, wherein said electrical signal is converted into a discharge signal via a discharge head having at least one electrode grounded by the tissue.

16. The method of claim 15, further comprising administering a gas from said discharge head during or following step (a).

17. The method of claim 14, wherein the tissue is a hair shaft and said electrical current maximizes at 4-6 microamperes.

18. The method of claim 17, wherein said electrical signal is 1-10 KV, and said discharge signal is generated by a discharge head having a conductivity of 10⁵-10⁹ ohm.

19. The method of claim 18, wherein said discharge signal also generates an electromagnetic wave tuned for propagation through said hair shaft.

20. The method of claim 18, wherein said electromagnetic wave is in frequency of 9-11 MHz.

21. The method of claim 14, wherein the tissue is skin and said electrical current maximizes at 9-11 microamperes.

22. The method of claim 21, wherein said electrical signal is 5 KV, and said discharge signal is generated by a discharge head having a conductivity of 10 8 -1010 ohms.

23. The method of claim 22, wherein said discharge signal also generates an electromagnetic wave tuned for propagation through said skin.

24. The method of claim 23, wherein said electromagnetic wave is in frequency of 0.01-3 GHz.

25. The method of claim 14, wherein the tissue is microorganism- infected tissue and said electrical current maximizes at 9-11 microamperes.

26. The method of claim 25, wherein said electrical signal is 3-6 KV, and said discharge signal is generated by a discharge head having a conductivity of 10⁴ to 10⁹ ohms.

27. The method of claim 26, wherein said discharge signal also generates an electromagnetic wave tuned for propagation through said microorganism.

28. The method of claim 27, wherein said microorganism is a fungus and said tissue is skin or nail tissue.

29. The method of claim 26, further comprising administering a gas to said microorganism-infected tissue during or following step (a).

30. The method of claim 27, wherein said electromagnetic wave is in frequency of 50 KHz.

31. A discharge head for treatment of tissue comprising:

(a) a first electrode disposed within a housing and being connectable to a power source;

(b) a second electrode disposed within said housing and being spaced apart from said first electrode so as to form a detectable spark gap, wherein a distance of said spark gap is adjustable.

32. The discharge head of claim 31, further comprising an optical sensor for sensing light emitted by a spark formed in said spark gap.

33. The discharge head of claim 31, further comprising a control circuit for processing said light sensed by said optical sensor and modifying a gap of said spark gap according to a frequency of said light.