System and method for treating biological tissue with a plasma gas discharge

• US 20060189976A1
• Filed: 01/18/2006
• Published: 08/24/2006
• Est. Priority Date: 01/18/2005
• Status: Active Grant

• Current Assignee: Alma Lasers
• Original Assignee: Alma Lasers International
• Inventors: Karni, Ziv, Britva, Alexander
• Granted Patent: US 9,215,788 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/042 using additional gas becoming plasma
• CPC Class Codes: A61B 18/20 using laser
• CPC Class Codes: A61B 2018/00452 Skin
• CPC Class Codes: A61B 2018/122 ionizing, with corona
• CPC Class Codes: H05H 1/2406 using dielectric barrier discharges, i.e. with a dielectric interposed between the electrodes
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: H05H 1/466 using capacitive coupling means, e.g. electrodes
• CPC Class Codes: H05H 1/4697 using glow discharges
• CPC Class Codes: H05H 2245/34 Skin treatments, e.g. disinfection or wound treatment

Abstract

Devices and methods for treating biological tissue using a plasma gas-discharge are disclosed herein. An electrode for igniting a gas flow to form a plasma gas-discharge, wherein the electrode is configured within the device such that upon encountering a surface of the biological tissue by the electrode, a path of current from the electrode to the surface of the biological tissue is formed, thereby igniting the gas flow and forming the plasma gas-discharge. In some embodiments, electromagnetic interactions between the treated biological tissue and the plasma gas discharge traversing the electromagnetic interaction gap shape the profile of the plasma gas discharge. According to some embodiments, the device includes an electrode for igniting gas of the gas flow, and electromagnetic interactions between the electrode and the skin determine, at least in part, the electromagnetic interactions that shape the profile of the plasma gas discharge. In some embodiments, the device further includes a housing for providing support for the electrode, wherein the electrode is disposed relative to the housing such that the electrode is substantially electrically unshielded by the housing, and the electrode is positioned to electromagnetically interact with a surface of the biological tissue to shape, at least in part, the plasma profile. According to some embodiments, the presently disclosed device includes a dual-purpose nozzle-electrode for gas delivery and for igniting the gas flow. A method of transdermal ion delivery of a plasma flux to biological tissue as a means of treating the biological tissue is also provided.

Claims

1. A device for treating biological tissue comprising:

a) an electrode for igniting a gas flow to form a plasma gas-discharge, wherein said electrode is configured within the device such that upon encountering a surface of the biological tissue by said electrode, a path of current from said electrode to said surface of the biological tissue is formed, thereby igniting said gas flow and forming said plasma gas-discharge.

2. The device of claim 1, wherein said electrode is a nozzle-electrode including a nozzle portion adapted to receive said gas flow.

3. The device of claim 2, wherein said nozzle-electrode is adapted to ignite said gas flow such that said plasma gas-discharge is formed, at least in part, outside of said nozzle portion.

4. The device of claim 1, wherein the device operates at or above atmospheric pressure.

5. The device of claim 1, wherein said plasma gas-discharge produced by the device is effective to treat the biological tissue by ablating the biological tissue.

6. The device of claim 1, wherein said plasma gas-discharge produced by the device is effective to treat the biological tissue by cutting the biological tissue.

7. The device of claim 1, wherein said plasma gas-discharge produced by the device is effective to treat the biological tissue by transdermal ion delivery to the biological tissue.

8. The device of claim 1, wherein said plasma gas-discharge produced by the device is effective to treat the biological tissue by heating the biological tissue.

9. The device of claim 1, wherein said plasma gas-discharge produced by the device is effective to treat the biological tissue by bio-photostimulation of the biological tissue.

10. The device of claim 1, wherein said plasma gas-discharge produced by the device is effective to treat the biological tissue by chemically reacting said plasma gas-discharge with the biological tissue.

11. The device of claim 1, wherein said gas flow is a diffusive gas flow.

12. The device of claim 1 further comprising:

(b) a gas source for producing said gas flow, said gas source provides at least one gas selected from the group consisting of;

helium, argon, neon, xenon, krypton, molecular oxygen (O₂), molecular nitrogen (N₂), oxides of nitrogen, oxides of carbon, water vapor, a volatile organic gas, and a volatile inorganic gas.

13. The device of claim 1, wherein said electrode is composed of at least one metal selected from the group consisting of:

aluminum, silver, gold, copper, and alloys thereof.

14. The device of claim 1 further comprising:

(b) a dielectric barrier associated with a surface of said electrode for reducing an electrical conductivity of said surface of said electrode, thereby impeding transmission of a conductive current to said surface of biological tissue.

15. The device of claim 1, wherein said electrode is dimensioned to form a torch-type profile from said plasma gas-discharge.

16. The device of claim 1, wherein said electrode has a dielectric cylindrical cavity attachment and is dimensioned to form said plasma gas-discharge such that said plasma gas-discharge substantially occupies the total cavity of said dielectric cylindrical cavity attachment.

17. The device of claim 1, wherein said electrode is dimensioned to form said plasma gas-discharge with a very low current density and a high discharge cross-section.

18. The device of claim 1, wherein said electrode is dimensioned to form a narrow flame-tongue (plasmatron) profile from said plasma gas-discharge.

19. The device of claim 1, wherein said electrode is dimensioned and positioned to interact with said surface of the biological tissue in a way that said surface of the biological tissue is a non-equipotential surface, allowing for simultaneous heating of the biological tissue and maintaining said plasma gas-discharge.

20. The device of claim 1, wherein said electrode is dimensioned with a bowl profile and positioned to directly contact the biological tissue in a way that said surface of the biological tissue is a non-equipotential surface, enabling said plasma gas-discharge to substantially fill interior volume of said electrode.

21. The device of claim 1, wherein said electrode has a dielectric cylindrical cavity attachment and is dimensioned with a spherical profile for directly contacting the biological tissue in a way that said surface of the biological tissue is a non-equipotential surface, providing said plasma gas-discharge with a ring-type profile.

22. The device of claim 1, wherein said electrode has a dielectric cylindrical conduit attachment which extends into interior of said electrode directly contacting the biological tissue, thereby igniting said plasma gas-discharge inside said dielectric cylindrical conduit attachment, said plasma gas-discharge is transported to the biological tissue by said gas flow.

23. The device of claim 1 further comprising:

(b) at least one additional component selected from the group consisting of;

a laser beam, an ultrasonic transducer, a UV light source, and a flash lamp, thereby additionally treating the biological tissue.

24. The device of claim 1, wherein said electrode serves as an antenna for said plasma gas-discharge and affects parameters of said gas flow for said plasma gas-discharge.

25. The device of claim 1 further comprising:

(b) a nozzle for gas delivery, said nozzle suitable for producing a strong decrease in temperature of said gas (adiabatic expansion).

26. The device of claim 1 further comprising:

(b) a nozzle for gas delivery, said nozzle suitable for producing a laminar gas flow.

27. The device of claim 1 further comprising:

(b) a nozzle for gas delivery, said nozzle suitable for producing a turbulent gas flow.

28. The device of claim 1 further comprising:

(b) a nozzle for gas delivery, said nozzle suitable for producing a gas flow effective for transdermal ion delivery.

29. The device of claim 1, wherein said plasma-gas discharge is produced by an RF power generator (amplifier) capable of producing an output RF power sufficient to ignite and sustain said plasma gas-discharge.

30. The device of claim 1 further comprising:

(b) an electrode control for regulating a power characteristic of said electrode.

31. The device of claim 30, wherein said electrode control includes an RF power source for providing RF power to said electrode.

32. The device of claim 30, wherein said electrode control includes a phase shifter capable of shifting a phase of directed traveling waves.

33. The device of claim 30, wherein said electrode control includes an impedance-matching network (IMN), said IMN capable of converting an aggregate impedance of the device including said plasma gas-discharge, said electrode, and the biological tissue (DET—

discharge-electrode-tissue) from a nominal value to a corrected value.

34. The device of claim 30, wherein said electrode control includes an RF resonator capable of cyclically accumulating and releasing a desired amount of energy.

35. The device of claim 30, wherein said electrode control includes:

(a) an RF power generator (amplifier) capable of producing an output RF power sufficient to ignite and sustain said plasma gas-discharge,

(b) a pulse-width modulation (PWM) controller, said PWM controller capable of causing said RF power generator to deliver said output RF power in pulses of a predetermined duration and amplitude with a desired frequency,

(c) a phase shifter capable of shifting a phase of directed traveling waves, said phase shifter capable of shifting a phase of directed traveling waves of said output power via a phase jump in order to facilitate both an ignition stage and an operation stage of said plasma gas-discharge,

(d) an impedance-matching network (IMN), said IMN capable of converting an aggregate impedance of the device including said plasma gas-discharge, said electrode, and the biological tissue (DET—

discharge-electrode-tissue) from a nominal value to a corrected value for both said ignition stage and said operation stage, said corrected value matching to a characteristic impedance of said RF power generator and said phase shifter so that said output traveling wave may sustain said plasma gas-discharge without being converted to a standing wave, and

(e) an RF resonator connected to said electrode, said RF resonator capable of cyclically accumulating and releasing a desired amount of energy for said operation stage, said RF resonator further capable of concentrating said desired amount of energy for said ignition stage.

36. The device of claim 14, wherein said dielectric barrier is supplied as a dielectric coating on said electrode.

37. The device of claim 14, wherein said electrode is constructed primarily of aluminum and said dielectric barrier is supplied as an alumina coating.

38. A device for treating biological tissue using a shaped plasma profile formed from a gas flow, the device comprising:

(a) an electrode for igniting the gas flow to produce a plasma gas-discharge, and

(b) a housing for providing support for said electrode, wherein said electrode is disposed relative to said housing such that said electrode is substantially electrically unshielded by said housing, and said electrode is positioned to electromagnetically interact with a surface of the biological tissue to shape, at least in part, the plasma profile.

39. The device of claim 38, wherein the device is configured such that said plasma-gas discharge is substantially located outside said housing.

40. The device of claim 38, wherein said electrode is attached to said housing via an electrode holder, said electrode holder serves both to position said electrode relative to said housing and to deliver gas of said gas flow to said electrode.

41. The device of claim 38, wherein at least a portion of said electrode is exposed on said housing to allow direct contact with said surface of the biological tissue.

42. The device of claim 38, wherein a disposition of said electrode is adjustable relative to said housing to allow movement along the surface of the biological tissue as a means of controlling a region of treatment of the biological tissue.

43. A device for treating biological tissue, the device comprising:

(a) an RF power generator (amplifier) capable of producing an output RF power sufficient to ignite and sustain a plasma gas-discharge,

(b) a pulse-width modulation (PWM) controller, said PWM controller capable of causing said RF power generator to deliver said output RF power in pulses of a predetermined duration and amplitude with a desired frequency,

(c) a phase shifter capable of shifting a phase of directed traveling waves, said phase shifter capable of shifting a phase of directed traveling waves of said output power via a phase jump in order to facilitate both an ignition stage and an operation stage of said plasma gas-discharge,

(d) an impedance-matching network (IMN), said IMN capable of converting an aggregate impedance of the device including said plasma gas-discharge, said electrode, and the biological tissue (DET—

discharge-electrode-tissue) from a nominal value to a corrected value for both said ignition stage and said operation stage, said corrected value matching to a characteristic impedance of said RF power generator and said phase shifter so that said output traveling wave may sustain said plasma gas-discharge without being converted to a standing wave, and

(e) an RF resonator connected to said electrode, said RF resonator capable of cyclically accumulating and releasing a desired amount of energy for said operation stage, said RF resonator further capable of concentrating said desired amount of energy for said ignition stage.

44. The device of claim 43, wherein coupled power is delivered from said RF power generator.

45. The device of claim 43, wherein said output RF power delivered to said plasma gas-discharge is coupled in continuous or pulsing mode.

46. The device of claim 43, wherein said phase shifter includes a trombone type.

47. The device of claim 43, wherein said phase shifter is at least partially constructed of coaxial cable.

48. The device of claim 43, wherein a phase shift provided by said phase shifter is variable.

49. The device of claim 43, wherein said IMN includes a fixed structure characterized by a shape selected from the group consisting of:

L-shaped, T-shaped, and π

-shaped structure.

50. The device of claim 43, wherein said IMN includes a broadband impedance transformer.

51. The device of claim 43, wherein said IMN is variable.

52. The device of claim 43, the device further comprising:

(f) a feeding cable, said feeding cable connecting said electrode and said RF resonator with said IMN.

53. The device of claim 52, wherein said feeding cable has a resonance length defined by n*?/2 length, where ? is a wavelength of said output RF power in material of said feeding cable and n is a whole number.

54. A device for treating biological tissue using a shaped plasma profile formed from a gas flow, the device comprising:

(a) a nozzle-electrode for gas delivery and for igniting the gas flow to produce a plasma gas-discharge, and

(b) a housing providing support for said nozzle-electrode, wherein said nozzle-electrode is disposed relative to said housing such that said nozzle-electrode is substantially electrically unshielded by said housing, and said nozzle-electrode is positioned to electromagnetically interact with a surface of the biological tissue to shape, at least in part, the plasma profile.

55. A method for treating biological tissue, the method comprising the steps of:

(a) supplying a gas flow to an electrode,

(b) upon bringing a surface of the biological tissue and an electrode into proximity with each other such that said electrode and said biological tissue are substantially electrically unshielded from each other, igniting said gas flow to form a plasma gas-discharge, and

(c) subjecting said surface of the biological tissue to said plasma-gas discharge, thereby treating the biological tissue.

56. The method of claim 55, wherein the biological tissue is treated by ablating the biological tissue.

57. The method of claim 55, wherein the biological tissue is treated by cutting the biological tissue.

58. The method of claim 55, wherein the biological tissue is treated by transdermally delivering ions to the biological tissue.

59. The method of claim 55, wherein the biological tissue is treated by heating the biological tissue.

60. The method of claim 55, wherein the biological tissue is treated by bio-photostimulating the biological tissue.

61. The method of claim 55, wherein the biological tissue is treated by chemically reacting said plasma gas-discharge with the biological tissue.

62. The method of claim 55, wherein the biological tissue is electrically grounded in order to interact with said plasma gas-discharge.

63. The method of claim 55, wherein the biological tissue is electrically floating in order to interact with said plasma gas-discharge.

64. The method of claim 55, wherein said plasma gas-discharge operates at or above atmospheric pressure.

65. The method of claim 55, the method further comprising the steps:

(d) producing an output RF power sufficient to ignite and sustain said plasma gas-discharge by means of an RF power generator (amplifier),

(e) causing said RF power generator to deliver said output RF power in pulses of a predetermined duration and amplitude with a desired frequency by means of by means of a pulse-width modulation (PWM) controller,

(f) shifting a phase of directed traveling waves of said output power via a phase jump in order to facilitate both an ignition stage and an operation stage of said plasma gas-discharge by means of a phase shifter,

(g) converting an aggregate impedance including said plasma gas-discharge, said electrode, and the biological tissue (DET—

discharge-electrode-tissue) from a nominal value to a corrected value for both said ignition stage and said operation stage, said corrected value matching to a characteristic impedance of said RF power generator and said phase shifter so that said output traveling wave may sustain the plasma gas-discharge without being converted to a standing wave by means of an impedance-matching network (IMN), and

(h) cyclically accumulating and releasing a desired amount of energy for said operation stage, said RF resonator further capable of concentrating said desired amount of energy for said ignition stage by means of an RF resonator connected to said electrode.

66. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode attached to the device via an electrode holder, said electrode holder also serves to deliver a gas to said electrode.

67. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode located in direct contact with said surface of the biological tissue.

68. The method of claim 55, wherein step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode movable on said surface of the biological tissue as a means of altering a location of treating the biological tissue.

69. The method of claim 55, the method further comprising the step of:

(d) positioning a dielectric barrier between said electrode and said surface of the biological tissue, said dielectric barrier impeding transmission of a conductive current.

70. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode exposed to atmosphere and having a dimension and a profile for producing said plasma gas-discharge that has a torch-type profile.

71. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode having a dielectric cylindrical cavity attachment and having a dimension and a profile for producing said plasma gas-discharge that occupies the total cavity of said dielectric cylindrical cavity attachment.

72. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode having a dimension and a profile for producing said plasma gas-discharge with a very low current density and a high discharge cross-section.

73. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode having a dimension and a profile for producing said plasma gas-discharge with a narrow flame-tongue (plasmatron) profile.

74. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode having a dimension and a profile for interacting with said surface of the biological tissue, in a way that said surface of the biological tissue is a non-equipotential surface, allowing for simultaneous heating of the biological tissue and maintaining of said plasma gas-discharge.

75. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode having a bowl profile for directly contacting the biological tissue in a way that said surface of the biological tissue is a non-equipotential surface, enabling said plasma gas-discharge to fill interior volume of said nozzle electrode.

76. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode having a dielectric cylindrical cavity attachment and having a spherical profile for partially directly contacting the biological tissue in a way that said surface of the biological tissue is a non-equipotential surface, providing said plasma gas-discharge with a ring-type profile.

77. The method of claim 55, wherein said step of igniting said gas flow from said electrode includes igniting said gas flow from an electrode having a dielectric cylindrical conduit attachment which extends into interior of said electrode directly contacting the biological tissue which yields a plasma gas-discharge ignited inside said dielectric cylindrical conduit attachment, said plasma gas-discharge is transported to the biological tissue by said gas flow.

78. The method of claim 55, the method further comprising the step of:

(d) employing at least one additional component selected from the group consisting of;

a laser beam, an ultrasonic transducer, a UV light source, and a flash lamp to additionally treat the biological tissue.

79. The method of claim 55, wherein said step of providing a gas flow includes providing a gas flow having flow characteristics suitable to produce a strong decrease in temperature of said gas (adiabatic expansion).

80. The method of claim 55, wherein said step of providing a gas flow includes providing a gas flow having flow characteristics suitable to produce a laminar gas flow characteristic.

81. The method of claim 55, wherein said step of providing a gas flow includes providing a gas flow having flow characteristics suitable to produce a turbulent gas flow characteristic.

82. The method of claim 55, wherein said step of providing a gas flow includes providing a gas flow having flow characteristics suitable to facilitate transdermal ion delivery.

83. The method of claim 55, wherein said steps (a) through (c) are performed in the order listed.

84. A method for treating biological tissue, the method comprising the steps of:

(a) supplying a gas flow to an electrode,

(b) allowing a path of current to form from said electrode to a surface of the biological tissue to concomitantly ignite said gas flow to form a plasma gas discharge, and

(c) subjecting said surface of the biological tissue to said plasma-gas discharge, thereby treating the biological tissue.

85. A method for treating biological tissue using a plasma gas-discharge, the method comprising the steps of:

(a) producing an output RF power sufficient to ignite and sustain said plasma gas-discharge by means of an RF power generator (amplifier),

(b) causing said RF power generator to deliver said output RF power in pulses of a predetermined duration and amplitude with a desired frequency by means of by means of a pulse-width modulation (PWM) controller,

(c) shifting a phase of directed traveling waves of said output power via a phase jump in order to facilitate both an ignition stage and an operation stage of the plasma gas-discharge by means of a phase shifter,

(d) converting an aggregate impedance including said plasma gas-discharge, said electrode, and the biological tissue (DET—

discharge-electrode-tissue) from a nominal value to a corrected value for both said ignition stage and said operation stage, said corrected value matching to a characteristic impedance of said RF power generator and said phase shifter so that said output traveling wave may sustain the plasma gas-discharge without being converted to a standing wave by means of an impedance-matching network (IMN), and

(e) cyclically accumulating and releasing a desired amount of energy for said operation stage, said RF resonator further capable of concentrating said desired amount of energy for said ignition stage by means of an RF resonator connected to said electrode.

86. A method for treating biological tissue using a shaped plasma profile the method comprising the steps of:

(a) providing a gas flow,

(b) igniting gas from said gas flow to produce a plasma gas-discharge,

(c) subjecting a surface of the biological tissue to said plasma gas-discharge, and

(d) using electromagnetic interactions between said subjected surface of the biological tissue and said plasma gas-discharge traversing an electromagnetic interaction gap, shaping a profile of said plasma gas-discharge, thereby treating the biological tissue.

87. A method for transdermal ion delivery of a plasma flux to biological tissue as a means of treating the biological tissue, the method comprising the steps of:

(a) subjecting a surface of the biological tissue to a plasma flux of a plasma gas discharge, and

(b) transdermally delivering the plasma flux to the biological tissue beneath said surface.

88. The method of claim 87, wherein said step of transdermally delivering the plasma flux further includes transdermally delivering a plasma flux of at least one species selected from the group consisting of:

atomic ions, molecular ions, atomic radicals, molecular radicals, excited-state ions, excited-state radicals, energetic ions, energetic radicals, cooled ions, cooled radicals, energetic electrons, and any components of feed gas.