Cold plasma generating system

Patent metadata

Field	Value
Publication number	US-11006994-B2
Application number	US-201515527499-A
Country	US
Kind code	B2
Filing date	Nov 19, 2015
Priority date	Nov 19, 2014
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

A system for generating cold plasma is presented, suitable for use in in-vivo treatment of biological tissue. The system comprising: a control unit connectable to an elongated member at a first proximal end of the elongated member. The elongated member comprises a plasma generating unit at a second distal end thereof and gas and electricity transmission channels extending from said first proximal end towards said plasma generating unit. The control unit comprises a gas supply unit configured to provide predetermined flow rate of selected gas composition through said gas transmission channel and a power supply unit configured to generate selected sequence of high-frequency electrical pulses, typically in mega Hertz range, directed through said electricity transmission channel, thereby providing power and gas of said selected composition to the plasma generating unit for generating cold plasma.

First claim

The invention claimed is:

1. A system for generating cold plasma, the system comprising:
a control unit connectable to an elongated member at a first proximal end of the elongated member;
wherein said elongated member comprises:
a plasma generating unit at a second distal end thereof and gas and
an electricity transmission channel extending from said first proximal end towards said plasma generating unit;

wherein the control unit comprises a gas supply unit configured to provide a selected gas composition through said gas transmission channel and a power supply unit configured to generate a selected sequence of high-frequency electrical pulses directed through said electricity transmission channel, thereby providing power and gas of said selected composition to the plasma generating unit for generating cold plasma; and
wherein:
said power supply unit comprises a resonance circuit configured for generating the high-frequency electrical pulses,
said electricity transmission channel comprises a coaxial cable characterized by a self-impedance, and
the coaxial cable is an element of the resonance circuit of the power supply unit which generates the high-frequency electrical pulses, the coaxial cable being electrically connected within the resonance circuit so that the self-impedance of the coaxial cable also serves as part of an impedance of the resonance circuit, the impedance acting to set a carrier frequency of the high-frequency electrical pulses.

2. The system of claim 1 , wherein said power supply unit, electricity transmission channel and plasma generation unit are configured to prevent electrical discharge into surrounding thereof, thereby enabling use of said plasma generating unit on live biological tissue.

3. The system of claim 2 , wherein said selected sequence of high frequency electrical pulses consists of a sequence of pulses having a repetition rate between 100 Hz and 600 Hz and carrier frequency between 500 kHz and 10 MHz and having peak voltage between 0.5 kV and 2 kV.

4. The system of claim 1 , wherein said selected sequence of high frequency pulses consists of a sequence of pulses having a pulse duration between 450 μs and 800 μs.

5. The system of claim 1 , wherein said electricity transmission channel is configured for preventing electricity discharge and electromagnetic radiation into surrounding thereof to thereby prevent damage to surrounding biological tissue.

6. The system of claim 5 , wherein said electricity transmission channel is configured as a coaxial electricity transmission cable having an internal conductor configured to carry electricity signal and an external conductor shielding between an electrical potential in said internal conductor and a surrounding of the cable; said external conductor is kept at ground potential.

7. The system of claim 1 , wherein said gas supply unit is configured to supply a predetermined flow of gas having a Penning mixture along said gas transmission channel, thereby providing said gas mixture having low breakdown threshold.

8. The system of claim 7 , wherein said Penning gas mixture is a mixture of Neon and Argon gasses with ratio between 98:2 and 99.9:0.1 of Ne:Ar.

9. The system of claim 1 , wherein said elongated member, including said gas and electricity transmission channels thereof, is flexible.

10. The system of claim 1 , wherein said elongated member comprises a distal portion, said distal portion being rigid thereby enabling direction of the distal end to a desired location.

11. The system of claim 1 , wherein said elongated member is configured to be inserted into a working channel of an endoscope for selectively generating cold plasma within a cavity of a biological tissue.

12. The system of claim 1 , wherein said elongated member further comprises one or more sensors mounted at said second distal end thereof, and said one or more sensors comprise at least one of the following: thermal sensor, spectrometry sensor, optical sensor, photo-spectrometer sensor, electric field sensor and magnetic field sensor.

13. The system of claim 1 , wherein said plasma generating unit, located at said second distal end of the elongated member, is configured as a dielectric barrier discharge plasma generating unit and comprises a first internal electrode providing electrical potential and a second external electrode, at least one of said first and second electrode is covered by a dielectric layer of predetermined thickness; potential difference between said first and second electrodes cause electrical discharge through gas flowing between said first and second electrodes to thereby generate said plasma.

14. The system of claim 1 , configured for generating cold plasma being characterized in having a temperature below 50° C.

15. The system of claim 1 , wherein said plasma generating unit, when operated with input gas and electric pulses, generates a plasma plume having a length beyond an exit aperture of the plasma generating unit of between 2 mm and 20 mm.

16. The system of claim 1 , configured for use in treatment of cancer in living tissue.

17. The system of claim 1 , wherein said elongated member is configured to be directed to apply cold plasma at natural or surgically made cavities in living organisms.

18. The system of claim 1 , wherein said gas supply unit is configured to supply a predetermined flow of helium along said gas transmission channel.

19. The system of claim 1 , wherein said elongated member is configured to be inserted into a working channel of a flexible endoscope for selectively generating cold plasma within an existing natural cavity of a biological tissue accessed through an existing natural orifice.

20. The system of claim 1 , wherein damage producing a change in the capacitance of the coaxial cable changes the tuning of the resonance circuit.

21. The system of claim 1 , wherein the coaxial cable is electrically connected within the resonance circuit as a capacitance element.

22. A method for generating cold plasma within a biological cavity, the method comprising:
providing a flow of gas of predetermined material composition and predetermined flow rate through an elongated transmission channel to a desired location within said biological cavity;
generating, using a carrier frequency selected by a resonance circuit characterized by an associated impedance, a series of high frequency electrical pulses and transmitting said series through a shielded electricity transmission channel comprising a coaxial cable to said desired location; and
allowing discharge of potential difference resulting from said series of high frequency electrical pulses through said gas flow at close proximity to said desired location with the biological cavity, thereby generating cold plasma flow directed at said desired location;
wherein the coaxial cable is an element of the resonance circuit, electrically connected within the resonance circuit so that a self-impedance of the coaxial cable also serves as part of the impedance of the resonance circuit, tuning it to generate the carrier frequency.

23. The method of claim 22 , wherein the resonance circuit has a resonant frequency between 0.5 MHz and 10 MHz.

24. A cold plasma generator comprising:
a pulse generating circuit, configured to generate electric pulses by oscillation at a radio-range carrier frequency;
a transmission channel configured to transmit the generated pulses into a plasma-generating electrical field between two co

Assignees

• Technion Res & Dev Foundation
• Rambam Med Tech Ltd

Inventors

• Krasik Yakov
• Felsteiner Joshua
• Slutsker Yakov
• Gil Ziv
• Cohen Jacob
• Binenbaum Yoav

Classifications

• H05H1/2406

  using dielectric barrier discharges, i.e. with a dielectric interposed between the electrodes · CPC title

• H05H2245/34

  Skin treatments, e.g. disinfection or wound treatment · CPC title

• H05H2245/32

  Surgery, e.g. scalpels, blades or bistoury; Treatments inside the body · CPC title

• H05H1/2465

  the plasma being activated by inductive coupling, e.g. using coiled electrodes · CPC title

• H05H1/246

  the plasma being activated using external electrodes (H05H1/245 takes precedence) · CPC title