WO2015059702A1

WO2015059702A1 - Cold plasma treatment

Info

Publication number: WO2015059702A1
Application number: PCT/IL2014/050919
Authority: WO
Inventors: Amnon Lam; Michael MALLER
Original assignee: Ionmed Ltd.
Priority date: 2013-10-24
Filing date: 2014-10-22
Publication date: 2015-04-30

Abstract

Cold plasma treatment devices and methods are provided. Devices comprise a nozzle configured to receive a first gas (e.g., helium) and an auxiliary gas (e.g., oxygen, ozone, nitrogen, nitric oxide, air) and direct a flow thereof towards a treatment end of the nozzle, and electrode(s) configured to apply a radiofrequency electromagnetic field on at least a part of the volume enclosed by the nozzle. The field is configured to ionize at least part of the received first gas, to emit plasma at the treatment end of the nozzle.

Description

COLD PLASMA TREATMENT

BACKGROUND OF THE INVENTION

1. TECHNICAL FIELD

[0001] The present invention relates to the field of cold plasma treatment, and more particularly, to improved cold plasma treatment devices.

2. DISCUSSION OF RELATED ART

[0002] Cold plasma welding is an innovative wound treatment method, which promotes wound healing under various medical circumstances. Examples for plasma treatment devices can be found in U.S. Patent Publication No. 20120283732, which is incorporated herein by reference in its entirety.

SUMMARY OF THE INVENTION

[0003] One aspect of the present invention provides a plasma treatment device comprising a nozzle configured to receive a first gas and an auxiliary gas and direct a flow thereof towards a treatment end of the nozzle, and at least one electrode configured to apply a radiofrequency (RF) electromagnetic (EM) field on at least a part of a volume enclosed by the nozzle, the RF EM field configured to ionize at least part of the received first gas, to emit plasma at the treatment end of the nozzle.

[0004] These, additional, and/or other aspects and/or advantages of the present invention are set forth in the detailed description which follows; possibly inferable from the detailed description; and/or learnable by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] For a better understanding of embodiments of the invention and to show how the same may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings in which like numerals designate corresponding elements or sections throughout.

[0006] In the accompanying drawings:

[0007] Figures 1A-1C and 2 are high level schematic illustrations of a plasma treatment device, according to some embodiments of the invention. [0008] Figure ID is a high level schematic illustration of auxiliary gas introduction, according to some embodiments of the invention.

[0009] Figures 3A and 3B schematically illustrate electrode(s) at the treatment end of the nozzle, according to some embodiments of the invention.

[0010] Figure 3C schematically illustrates a division of the treatment end of the nozzle into compartments, according to some embodiments of the invention.

[0011] Figures 4A and 4B schematically illustrate a branched electrode at the treatment end of the nozzle, according to some embodiments of the invention.

[0012] Figures 5A-5C schematically illustrate the branched electrode with a rotating shield at the treatment end of the nozzle, according to some embodiments of the invention.

[0013] Figure 6 A schematically illustrates an isometric view of an inner part of an anastomosis- treating device configured to emit plasma peripherally and circularly, according to some embodiments of the invention.

[0014] Figure 6B schematically illustrates a concentric-cones configuration of the treatment end of the nozzle, according to some embodiments of the invention.

[0015] Figure 7 is a high level schematic flow chart illustrating a method, according to some embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0016] 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.

[0017] Before at least one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is applicable to 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.

[0018] Figure 1A is a high level schematic illustration of a plasma treatment device 100 according to some embodiments of the invention. Plasma treatment device 100 is configured to receive gas supply 130 and ionize at least part of it into cold treatment plasma 150 which is configured to have any one of various effects on a treated tissue, such as disinfection, coagulation of fluids and activation of healing processes. As non-limiting examples, NO (nitric oxide) radicals may be used to promote wound healing, ozone (O₃) may be used to kills cancer cells, and both NO and O₃ may be used to perform disinfection. Gas supply 130 may comprise several components 132, 134 which are used to produce different ions and radicals in plasma 150 to achieve different medical purposes.

[0019] Plasma treatment device 100 comprises a nozzle 110 configured to receive a first gas 132 (e.g., helium and/or argon) and an auxiliary gas 134 (e.g., oxygen, nitrogen, argon, air) and direct a flow thereof (138) towards a treatment end 112 of nozzle 110. Plasma treatment device 100 further comprises at least one electrode 120 configured to apply a radiofrequency (RF) electromagnetic (EM) field on at least a part of a volume enclosed by nozzle 110, the RF EM field configured to ionize at least part of the received first gas, to emit plasma 150 at treatment end 112 of nozzle 110, e.g., onto tissue 80.

[0020] Helium (He) may be used as a suitable gas for plasma generation, as it easily forms cold and stable plasma. Another possibility is argon, as are mixtures of helium and argon. Free radicals may be generated (serially or in a parallel manner) and mixed with helium to contribute to the chemical activity of the plasma which may be beneficial as a treatment or as part of treatment such as tissue welding and wound healing. For example, such activities may be one or few of: cross linking and polymerization (hardening) of the "welding" material, disinfection of the tissue surface, selective killing of cancerous cells, blood coagulation and/or wound healing. Adding of gases, other than He, may be beneficial and improve the plasma treatment outcome, and contribute for example to disinfection of tissue surface prior to welding the tissue or as a preparation of the surface before skin graft is applied; to enhance chronic wound healing; to kill cancerous cells on or near the tissue surface after excision or ablation of a tumor prior to closing the wound.

[0021] In certain embodiments, plasma treatment device 100 further comprises a chamber 160 within nozzle 110 which is configured to receive at least part 136 of auxiliary gas 134, and at least one second electrode 125 configured to apply a RF EM field within chamber 160 to ionize at least part of the auxiliary gas 136, to emit plasma thereof 151 from chamber 160 into nozzle 110. For example, auxiliary gas 134 may comprise any of oxygen, nitrogen and air, e.g., to enrich plasma 150 with free radicals. First gas 132 and auxiliary gas 134 may be mixed at chamber 160 and/or after chamber 160 (see flow 132 adding to plasma 151 and residual auxiliary gas 134 exiting chamber 160, to yield flow 138).

[0022] In embodiments of the invention, air (or air-He mixture) 136 may be ionized by pair of "air" RF excitation electrodes 125. Electrodes 125, connected to feeding RF circuitry 165, may be configured to create plasma 150A in air or mixture 136 and emit (151) plasma 150A into nozzle 110 to mix with first gas 132 and yield enriched first gas 138. Generally, creating plasma in air-He mixture may require applying a higher electric field than in pure He. High electric field may be created by smaller separation of electrodes 125, increased RF power, or combination thereof. Optionally, air electrodes 125 are not insulated.

[0023] Air (or mixture Air-He) plasma 151 is optionally further mixed with pure He (or other plasma gas) to result in flow 138 before it reaches a "mix" electrode 120. Optionally "mix" electrode 120 is operated as a unipolar electrode. Optionally tissue 80 is grounded. Optionally "mix" electrodes 120 are used and operated as bipolar/non-direct electrodes.

[0024] Optionally "air" and "mix" RF electrodes 125, 120 (respectively) may be separated. Optionally "air" electrode(s) 125 are located in inner chamber 160 and "mix" electrode(s) 120 is a bottom electrode located at treatment end 112 near tissue 80.

[0025] In certain embodiments, "air" and "mix" RF electrodes 125, 120 (respectively) may be connected together to the RF power supply 165. Alternatively, "air" and "mix" RF electrodes 125, 120 (respectively) may be activated separately. As examples, "air" and "mix" RF electrodes 125, 120 (respectively) may be activated at the same time; only "air" or "mix" RF electrodes 125, 120 (respectively) may be activated; "air" and "mix" RF electrodes 125, 120 (respectively) may be alternating in their activated; or any combination of the above (partially concurrent activation) may be used.

[0026] In some embodiments, monopolar/direct plasma excitation configurations may be used and the optimal Air 134 to He 132 ratio may be between 1 and 10%. Optionally the Air to He ratio range is 1% and 50%. Alternatively, bipolar/non-direct plasma excitation configuration may be used and the optimal Air 134 to He 132 ratio may be between 10% and 100%. Optionally, the bipolar/non- direct plasma flows downstream to tissue 80. Optionally, combination of bipolar/non-direct and monopolar/direct plasma excitation may be used. Other air to plasma gas ratios or gases other than He may be used. [0027] In certain embodiments, outer flow 138 of first gas 132 (e.g., helium) may be configured and controlled to serve any of the following purposes: (i) cooling of inner chamber 160 where the (possibly more intense) air plasma is formed 150A, (ii) diluting air plasma 151 and keeping the radicals thereof from recombining, and/or (iii) creating low temperature plasma 150 between bottom electrode 120 and treated surface 80.

[0028] In some embodiments, the alteration of power 165 between electrodes 125 and/or 120 may have a frequency of 0.1 Hz to 20 Hz.

[0029] For non-simultaneous excitation of air and mix electrode 125, 120 (respectively), the excitation of the different electrodes may be in any one of the following ways: (i) using different RF supply 165 for each electrode (or electrode pair, for bipolar/non-direct excitation) 125, 120. This allows flexibility in the separately changing the excitation parameters independently, (ii) using one RF supply (located at and associated with a control unit 166) 165 and separate RF cables for each electrode (or electrode pair, for bipolar/non-direct excitation) 125, 120, and a switch at control unit 166 to direct the power to one, or both electrodes 125, 120 and/or (iii) using one RF supply (located at control unit 166) 165, a single RF cable and a switch (e.g., located at the tip of nozzle 110) to direct the power to one, or both electrodes 125, 120.

[0030] In some embodiments, an spacer disk 115 having a plurality of holes may be placed in gas stream 138 to ensure mixing of the different gases or of first gas 132 and plasma 151. Spacer 115 may be used as a structural member, holding internal parts in place. Spacer 115 may be made of electrically insulating material.

[0031] Figure IB is a high level schematic illustration of plasma treatment device 100, according to some embodiments of the invention. Plasma treatment device 100 illustrated in Figure IB further comprises a member 170 connected to electrode(s) 120, within nozzle 110. Member 170 may be static or be dynamic, for example, member 170 may be connected to chamber 160 by a spring-like rod 172 and be rotated (170B) or moved (170A) during operation of plasma treatment device 100. Rotation 170B and/or movement 170A may be induced or enhanced by flow 138 and/or flow 132 impacting on member 170. In certain embodiments, electrode(s) 120 may be attached to any of chamber 160, spacer 115 and/or member 170, and may also be moved to control the quality of plasma 150, e.g., to make it more uniform and avoid plasma hot spots. Such designs may be configured to overcome the following difficulties in the prior art. When plasma devices are operated, especially with nozzles 110 having treatment end 112 with a large diameter, plasma 150 may create "channels" or "streamers" where ions are concentrated and the current easily flows ("hot spots"), and also some "cold-spots" which are not visited by plasma 150. Heating may thus be concentrated at the active channels and cause local overheating and thermal damage to tissue 80 at the hot spots. Additionally, the therapeutic effects at the cold spots may be insufficient. Even when plasma 150 is not on all the times it may re-ignite at the same channels because the local conditions (e.g., distance to tissue 80) causes the creation and determines the locations of the channels and/or due to plasma memory caused by surface charges deposited on one of electrodes 120, local heating and/or ions lifetime, surface effects (e.g., desiccation of tissue 80 that may increase the electrical resistance, or other physical or chemical changes. Certain embodiments of plasma treatment device 100 overcome these difficulties and produce uniform plasma 150 over large treatment ends 112. In certain embodiments, member 170 may be configured and/or positioned to control flow 138, before or after spacer 115, e.g., to adjust flow parameters and hence extent of produced plasma 150.

[0032] In certain embodiments, plasma 150 may be turned off at intervals by control unit 166, as part of the operation or for self-testing (as may be needed because the readings of the flow and other parameters while RF on is difficult due to the RF noise). Self-testing may be carried out every 1-3 seconds, and for a duration of up to 100 ms (milliseconds). To overcome the hot-spots problem, the user may move device 100. However, disclosed device-level solutions do not require skill and attention and prevent application of plasma 150 beyond the desired treated area. In some embodiments, automatic motion may be achieved by mechanically moving electrode(s) 150 within nozzle 110. Direction of motion may be linear (for example undulation motion) or circular motion. Motion may be cause by an electric motor or actuator (see Figure 4B below), or by flow of gas (e.g., dedicated gas flow or plasma gas flow 138).

[0033] In certain embodiments, electrode 120 may be arranged to vibrate (e.g., when connected to a connector 172 such as spring-like rod 172). Connector 172 may connect bottom (mix) electrode 120 to air RF electrode 125. Connector 172 may be an RF conduit and as a mechanical flexible support for mix electrode 120. In certain embodiments, gas current (flow 138) over mix electrode 120 may be configured causes mix electrode 120 to vibrate or flutter. Optionally, member 170 may be configured as wings which are attached to rod 172 or to electrode 120 to affect motion of electrode 120. In certain embodiments, a wind turbine or gas-operated motor (see Figure 4B below) may be used for vibrating electrode 120. Optionally a separate gas pipe (not shown) may be used for the gas moving electrode 120. Alternatively or additionally, an electric motor (see Figure 4B below) may be used to vibrate electrode 120. For example a vibrator, a solenoid or/and a piezoelectric element may be used. Alternatively or additionally, the electrode motion may be activated by the onset of RF power. For example, connecting rod 172 may be made of a thermal bimetal element and create lateral motion due to the heat of plasma 151 or 150, and return to its original shape when cooled by flowing gas 138. In some embodiments, nozzle 110 may comprise sensors (not shown) configured to detect the electrode motion. Indication and alert may be activated when electrode 120 is not moving. Optionally, when electrodes 120 fail to move, sensor data may be used to stop the process.

[0034] In certain embodiments, electrode 120 may be unipolar and operate with tissue 80 functioning as the second electrode to generate plasma 150 directly. Direct plasma contact may have enhanced plasma welding efficacy with respect to indirect plasma application. The latter may have advantages relating to safety and uniformity of the cold plasma, which may be weighed per application with respect to advantages of direct application.

[0035] Figure 1C is a high level schematic illustration of plasma treatment device 100 according to some embodiments of the invention. Device 100 may be used externally onto a skin surface or any other tissue surface, or internally, e.g., laparoscopically, e.g., within body cavities or vessels. A perforated grid 140 may be grounded and located in proximity to tissue 80. Plasma 150 may be configured to be produced between grid 140 and active electrode 120 and flow out to tissue 80 through holes 142 in grid 140. Such configurations may allow very proximate plasma application to tissue 80 yet avoiding direct contact between plasma 150 and tissue 80.

[0036] Grid 140 may be insulated at its bottom side (close to tissue 80) and exposed at the upper side (close to active electrode 120) in order to control plasma current flow 150 and prevent flow of RF current to tissue 80. In some embodiments, grid 140 may be completely covered with electrical insulation, or exposed. Grid 140 may be connected through variable impedance 145 as described U.S. Patent Publication No. 20120283732. In certain embodiments, the variable load may be a transistor that is controlled by controller 166 and defines the effective controlled ground electrode for the plasma. The total controlled ground electrode, including the cable on the plasma side of the transistor may have a total electrical capacitance and conductive impedance that do not allow plasma to ignite on the controlled ground electrode when the transistor is in an open state. It should be noted that when inserting a conductive material in the plasma pass way, if it has large enough capacitance/conductive impedance , the plasma ignites on it even if it is not connected to the ground. Thus, the controlled ground electrode may be constructed to have a low capacitance/conductive impedance so that the plasma does not ignite on it while not connected to ground.

[0037] Figure ID is a high level schematic illustration of auxiliary gas introduction, according to some embodiments of the invention. Nozzle 110 of plasma treatment device 100 may comprises a central constriction 133 configured to introduce auxiliary gas 134 into received first gas 132 utilizing the Venturi effect. Device 100 may further comprise a restrictor 131 configured to control and regulate the flow of auxiliary gas 134 into central constriction 133. Restrictor valve 131 may be used to synchronize the air (or other auxiliary gas) intake and the RF excitation. Optionally valve 131 may be an electronically controlled valve (a proportional valve) or an electronically activated (on/off) valve, either controlled by control unit 166 that controls the operation of the RF supply and/or other elements of device 100 such as the flow of He. Alternatively valve 131 may be manually activated by the user, mechanically or electronically.

[0038] In certain embodiments, an additional gas tank and gas delivery and control devices may be used, or oxygen (0₂) and nitrogen (N₂) may be used from the air which is available at unlimited quantities in the room. According to an exemplary embodiment of the current invention, a pump is used for pumping room air and directing air 134 into the plasma head (nozzle 110). Optionally the air may be mixed with the plasma gas at a control box or be delivered in a separate pipe to the plasma head. Optionally the pump is located at or near the control unit. Optionally the pump is an electric pump. Optionally the pump is a miniature electric pump. Optionally the pump is located at or near the plasma head. Air from the room may be added to the gas mixture without using a pump by using Venturi suction device. Venturi suction may be generated using the flow of He to suck in room air. Venturi suction may be created anywhere along the plasma gas conduit, and the amount of air added to the plasma gas may be controlled by a valve or restrictor 131 that may be used to shut down the flow of air completely if desired.

[0039] Optionally, control unit 166 comprises one or few of: sensors indication, warnings, and status display devices. Such devices may be: gas mixture sensors; control and verification of correct Air/He ratio; gas flow sensors of one or both air and He flow to monitor the flow of gasses; an indicator if the flow is outside the limits - activate a warning and /or activate self-shutoff of the RF power or shutoff the operation of the system. In some embodiment oxygen (0₂) may be provided from an oxygen generator (not shown) that generates 0₂ from the room air. 0₂ or 0₂-enriched air may be used. Alternatively or additionally, the N₂ separated from the air may be used to provide N₂ or N₂-air mixture.

[0040] Figure 2 is a high level schematic illustration of plasma treatment device 100, according to some embodiments of the invention. Nozzle 110 may have an increasing cross section toward treatment end 112. At least one electrode 120 may be spirally wrapped around nozzle 110 with an increasing diameter. Nozzle 110 and electrode(s) 120 may be configured to apply the RF EM field configured to ionize introduced gas 130 (e.g., first gas 132 and/or auxiliary gas 134 and/or flow 138 representing a gas mixture) to gradually increase the dimensions of the produced plasma (in the illustrated example, from plasma 150A through plasmas 150B, 150C, 150D and 150E to plasma 150 with ever larger dimensions) to yield plasma 150 over a large area at treatment end 112 of nozzle 110. For example, emitted plasma 150 may have a diameter of 1, 2 or 3-5 centimeters. In certain embodiments, electrode(s) 120 may exhibit a gradient in its resistance and/or its mechanical or electrical dimensions to ensure continuous increase in the dimensions of the produced plasma region. Chamber 160 and electrode(s) 125 may be configured as well to have an increasing cross section in gas flow direction, and similar configurations may apply to chamber 160 and electrode(s) 125 as disclosed for nozzle 110 and electrode(s) 120. Device 100 may comprise a perforated treatment end cover 140 which may be similar to grid 140 or may simply be a perforated protective or flow regulating element. In certain embodiments, cover 140 comprises a spacer 141 configured to maintain a specified separation between treatment end 112 and treated tissue 80 such as the skin. The specified separation distance may be configured according to safety and efficiency considerations, and may be different in different treatment types and according to different treatment parameters. Spacer 141 may be rigid or soft and have different forms. For example, spacer 141 may comprise a rigid ring having a constant of a changing diameter, or may comprise a soft skirt, possibly transparent, that enables the user to modify the specified gap between treatment end 112 and tissue 80 with given limits. Transparency of spacer may allow monitoring the treatment over the whole area of tissue 80.

[0041] Certain embodiments comprise plasma treatment device 100 comprising nozzle 110 configured to receive gas 132 and direct a flow thereof (138) towards treatment end 112 of nozzle 110, and at least one electrode 120 configured to apply the RF EM field on at least a part of a volume enclosed by nozzle 110 to ionize at least part of the received gas, to emit plasma at treatment end 112 of nozzle 110. Nozzle 110 may have an increasing cross section toward treatment end 112.

[0042] Certain embodiments comprise plasma treatment device 100 comprising nozzle 110 configured to receive gas 132 and direct a flow thereof (138) towards treatment end 112 of nozzle 110, and at least one electrode 120 configured to apply the RF EM field on at least a part of a volume enclosed by nozzle 110 to ionize at least part of the received gas, to emit plasma at treatment end 112 of nozzle 110. At least one electrode 120 may be spirally wrapped around nozzle 110 with an increasing diameter. [0043] Figures 3A and 3B schematically illustrate electrode(s) 120 at treatment end 112 of nozzle 110, according to some embodiments of the invention. Figures 3A and 3B schematically illustrate several concentric electrodes 120A, 120B, 120C which are interconnected by supports 122 which provide mechanical support (any number of electrodes 120 may be used, three is used as a non- limiting illustrative number). Supports 122 and connections 123 may be conducting or insulating. Electrodes 120A-120C and supports 122 may be insulated (e.g., coated by an insulation layer). Electrodes 120A-120C may be differently or separately energized with RF power. Figure 3C schematically illustrates a division of treatment end 112 of nozzle 110 into compartments 111A- 111C, according to some embodiments of the invention. In the illustration, the end of nozzle 110 comprises multiple concentric cones 110A, HOB, HOC (see e.g., Figure 6B) that define respective compartments 111 A, 11 IB, 111C with respective electrodes 120 A, 120B, 120C placed between the cones. Treatment end 112 and possibly part of nozzle 110 itself may be divided into compartments 111A-111C which correspond to respective concentric electrodes 120A-120C. Plasma 150 may be controlled for each compartment 111A-111C by respective electrode 120A-120C.

[0044] In certain embodiments electrodes 120A-120C may be energized sequentially, for example, any of the following operation patterns may be employed: one set of electrodes (or one electrode) working at a time; one set electrodes (or one electrode) not working at a time; any other combination including random or pseudo-random activation; controlled activation wherein when the current is sensed and found to increase in an electrode, that electrode is powered down momentarily; the power on the electrodes is turned on and off; and the power on the electrodes is increased and decreased.

[0045] Switching the power to electrodes 120A-C may be done at control unit 166, wherein each electrode (or electrodes set) may be connected to control unit 166 via a separate RF cable, in any one of the following configurations: several RF generators, optionally each connected to one electrode (or one set of electrode), the RF generators may be operated in sequence; one RF signal generator and a plurality of RF power amplifiers (controlling the supplied power) may be used, optionally each connected to one electrode (or one set of electrode); one RF generator may be used and connect in sequence to the electrodes using a mechanical distributer; one RF generator may be used and connected in sequence to the electrodes using (electro mechanic or solid state) HV relays, or switches. Alternatively, one RF cable may be used from control unit 166 to the plasma head (electrode 120 in nozzle 110), and switching RF power between electrodes 120 may be carried out in the head using any of the methods described above. Similar supply and connection patterns may be applied to electrodes 125.

[0046] Any of electrodes 120, 125 may be shaped electrodes, for example, any of the following and their combinations: (i) A spiraled electrode made of a single, bent (optionally insulated) wire, wire thickness may be varying along the wire, and the tightness of the spiral may be varying along the wire. This type of electrode may also ignite an ICP (Inductive coupled plasma) in the middle of the spiral, (ii) Concentric rings electrode of different diameters. The rings may be in different planes, (iii) Electrodes having complex shapes, such as branched electrodes. Complex shaped electrodes may be created by any of laser cutting, by lithography (free standing or on a substrate), by electro- erosion, by 3D printing or by other methods known in the art. Complex shaped electrodes may be planar, or have a three dimensional shape.

[0047] Certain embodiments comprise plasma treatment device 100 comprising nozzle 110 configured to receive gas 132 and direct a flow thereof (138) towards treatment end 112 of nozzle 110, and at least one electrode 120 configured to apply the RF EM field on at least a part of a volume enclosed by nozzle 110 to ionize at least part of the received gas, to emit plasma at treatment end 112 of nozzle 110.

[0048] Certain embodiments comprise plasma treatment device 100 comprising nozzle 110 configured to receive gas 132 and direct a flow thereof (138) towards treatment end 112 of nozzle 110, and at least one electrode 120 configured to apply the RF EM field on at least a part of a volume enclosed by nozzle 110 to ionize at least part of the received gas, to emit plasma at treatment end 112 of nozzle 110. At least one electrode 120 may comprise a plurality of concentric electrodes 120A-C

[0049] Figures 4A and 4B schematically illustrate branched electrode 120 at treatment end 112 of nozzle 110, according to some embodiments of the invention. Figure 4A is a schematic top view of the branching of some electrode embodiments, while Figure 4B is a schematic perspective view of branched electrode 120 connected to a motor 175 which may be configured to move, rotate (176) or vibrate electrode 120. Motor 175 may be supported on nozzle 110, chamber 160, spacer 115, member 170, connector 172 or any other structural element of device 100. Branched electrode 120 may be configured to span at least a part of treatment end 112 of nozzle 110. In operation, branched electrode 120 may be rotated to yield a uniform plasma emission 150 onto tissue 80. Parts or whole electrode 120 may be insulated. [0050] Figures 5A-5C schematically illustrate branched electrode 120 with a rotating shield 180 at treatment end 112 of nozzle 110, according to some embodiments of the invention. Rotating shield 180 may have at least one opening 184 in a plate-like cover 182 of treatment end 112. Rotating shield 180 may be positioned between branched electrode 120 and treatment end 112 of nozzle 110. Shield 180 may be rotated (185) to yield a uniform plasma emission 150 beyond branched electrode 120. Shield 180 may be made of electrically insulating material. The number, shape and sizes of opening(s) 184 in shield 180 may be selected according to gas flow considerations to yield even gas and plasma distribution. In certain embodiments, gas flow 138 may be directed to opening 184 only.

[0051] In the exemplary depicted embodiment, "bird legs" shape electrode is used, similar to the gas flow channels used in the semiconductor industry for cooling of the backside of wafers in plasma chambers. However, other electrode configurations may be used. Such embodiments may be used in device 100 comprising air-He mixture intake with separated air and mix electrodes 125, 120 respectively, however such embodiments may be used in other plasma heads (e.g. for pure inert plasma gas).

[0052] In some embodiments, bottom electrode 120 may be optionally concave to have the center of electrode 120 farther removed from tissue 80 than its peripheral (see Figure 5A). While the relative speed of motion of the electrode's peripheral parts is high, the center is relatively stationary with respect to tissue 80 and may develop a plasma hot spot. Increasing its distance from tissue 80 may inhibit the creation of the central hot-spot.

[0053] In some embodiments, bottom electrode 120 may be mounted on a spindle or a bearing, and be shaped to rotate under the influence of gas flow 138. In other embodiments, member 170 comprising wings such as a propeller, windmill or turbine wings may be connected to lower electrode 120 for efficient transfer of motion from gas 138 to electrode 120. In some embodiments, mechanical reduction gear may be used for efficient transfer of motion from gas 138 to electrode 120. In some embodiments, a combination of vibration and rotation motions of electrode(s) 120 and/or 125 may be used. In some embodiments, device 100 may comprise sensors to detect the electrode motion. Indication and alert may be activated when electrode 120 is not moving. Optionally, when electrodes 120 fail to move, sensor data may be used to stop the process.

[0054] In certain embodiments, device 100 may comprise means for assisting the user in maintaining proper distance between the plasma head (nozzle 110 and treatment end 112) and treated tissue 80, such as a mechanical stand-off (as described e.g., in U.S. Patent Publication No. 20120283732). In certain embodiments, device 100 may comprise a proximity sensor (or a plurality of sensors, for example one on each side of nozzle 110) to assist the user to maintain proper distance between treatment end 112 and treated tissue 80 and to maintain treatment end 112 leveled with respect to treated tissue 80. In certain embodiments, nozzle 110 may be stabilized with the assistance of a tripod or other stabilizer attached to, or stands by the patient bed. In certain embodiments, device 100 may be equipped with a soft skirt (see e.g., spacer 141 in Figure 2), to assist the user to judge and/or maintain proper distance between treatment end 112 and treated tissue 80 and to maintain treatment end 112 leveled with respect to treated tissue 80. For example, the skirt may be made of silicon rubber, be transparent and possibly have gas vent holes.

[0055] In certain embodiments, device 100 may applied onto soldering material, such as chitosan, albumin, collagen, alginate and similar biopolymers, for welding treated tissues. The soldering material may be configured as a film made of biocompatible material selected to enhance tissue treatment by plasma welding. The film may comprise holes configured to drain wound fluids. The film may comprise air bubbles configured to enhance the treatment. The film may be formed as an elongated strip and further comprise attached adhesive tape on at least one long side of the elongated strip. The film may further comprise at least one reinforced zone of pre-heated film material. The film may comprise at least one of: antiseptics, antibiotics, plasma-activated compounds, at least one compound selected to release free radicals upon exposure to the plasma, silver, silver salts and silver acetylate.

[0056] In a non-limiting example, an improved chitosan film (not shown) may comprise any of the following: small holes to drain wound fluids (e.g., blood) and optionally air bubbles trapped under the film as it is placed; imprinted bubbles which are obtained in the manufacturing process and allow plasma pass-through to the tissue and fluids out of the tissue; varying thickness, for example the film may have thick strips to prevent tearing; embedded strips or fibers to prevent tearing. The improved chitosan film may be dipped or impregnated with antiseptic, antibiotics, plasma activated chemicals and/or any chemical that creates free radicals when exposed to plasma (e.g., silver, silver salts or acetylate).

[0057] Figure 6A schematically illustrates an isometric view of an inner part of an anastomosis- treating device 100 configured to emit plasma 150 peripherally and circularly, according to some embodiments of the invention. In certain embodiments, plasma emitting device 100 may be configured to treat vessels internally, e.g., as a substitution for a circular stapler. Treatment end 112 may comprise peripheral pores 142 configured to emit plasma 150 laterally with respect to 110 nozzle. Possibly perforated grid or cover 140 having circumferential pores 142 may be attached to treatment end 112. Device 100 may be used for treating internal organ, for example performing anastomosis by generating a ring of plasma 150 that is configured to weld vessels internally, e.g., by inserting device 100 into the vessel (e.g., part of intestine or blood vessel), possibly further applying a solder to the proper location (inner side of vessel). For intestine anastomosis, plasma device 100 may work in conjunction with a standard anastomosis stapler which performs the initial approximation of the two intestine sides to be connected.

[0058] Figure 6B schematically illustrates a concentric-cones configuration of treatment end 112 of nozzle 110, according to some embodiments of the invention. Treatment end 112 may comprise a plurality of concentric cones 110A, HOB, HOC, each having peripheral pores 142 configured to emit plasma 150 laterally with respect to the cones. Cones 110A-C may define respective compartments 111A-C as explained above. Plasma 150 from peripheral pores 142 may be applied for performing anastomosis, as explained above. Device 100 and particularly treatment end 112 of nozzle 110 may be designed to be folded and compactly arranged into a tube with a diameter suited to fit into a laparoscopic surgery port (e.g., 4-13mm). After insertion into the stomach cavity, plasma head 100 may be pushed and while moving out of the holding tube, cones 110A-C may be deployed to yield a greater operation and plasma diameter and enable ignition of large surface plasma. RF electrodes 120 may be insulated and distributed evenly on treatment end 112 and/or cones to 110A- C yield uniform plasma treatment. In some embodiments, plasma laparoscopic device 100 has a folding head. In some embodiments, plasma laparoscopic device 100 has an umbrella shape. In some embodiments, plasma laparoscopic device 100 is folded to permit the tip to be maneuvered to the sides. In certain embodiments, device 100 has a tubular treatment end 112. Tubular treatment end 112 may comprise a tube with RF and ground electrodes along the inner side of the tube creating plasma all along electrodes 120 (the tube length may reach tens of centimeters). Tubular treatment end 112 may comprise a tube inside a tube wherein the outer tube is used for first gas (e.g., He) flow 132. Air (or air-He mixture) 134 flows through the inner tube and is ionized into plasma 151. The mixed plasma 138 flows out of the inner tube into the outer tube He flow, gets cooler and the free radicals are maintained until reaching the end of the entire tube and the tissue surface.

[0059] Certain embodiments comprise plasma treatment device 100 comprising nozzle 110 configured to receive gas 132 and direct a flow thereof (138) towards treatment end 112 of nozzle 110, and at least one electrode 120 configured to apply the RF EM field on at least a part of a volume enclosed by nozzle 110 to ionize at least part of the received gas, to emit plasma at treatment end 112 of nozzle 110. Treatment end 112 may comprise peripheral pores 142 configured to emit plasma 150 laterally with respect to nozzle 110. Device 100 may be configured as an inner part of an anastomosis-treating device configured to emit the plasma peripherally and circularly.

[0060] In certain embodiments, plasma device 100 may be configured to transfer high reactive species concentration to treated tissue 80 by diluting them in an inert gas, possibly to high surface areas in a uniform fashion. Plasma device 100 may further be configured to provide a controlled electrical energy to the treated surface.

[0061] Figure 7 is a high level schematic flow chart illustrating a method 200, according to some embodiments of the invention. Method 200 comprises configuring a nozzle to receive a first gas and an auxiliary gas and direct a flow thereof towards a treatment end of the nozzle (stage 210) and applying a RF EM field to ionize at least part of the received first gas, to emit plasma at a treatment end of the nozzle (stage 220).

[0062] Method 200 may comprise introducing the auxiliary gas into the received helium using the Venturi effect (stage 212).

[0063] Method 200 may comprise applying the RF EM field using a rotating branched electrode (stage 222) and possible partially shielding the rotating electrode from the treatment end (stage 223).

[0064] Method 200 may comprise applying a RF EM field within the nozzle to ionize at least part of the auxiliary gas, to emit plasma thereof into the nozzle (stage 225).

[0065] In certain embodiments, method 200 may comprise applying the RF EM field within the nozzle to gradually increase a spatial extent of the generated plasma (stage 230).

[0066] Method 200 may comprise emitting the plasma out of the treatment end of the nozzle at an area perpendicular to the flow direction in the nozzle, at a periphery of the nozzle, laterally from at least one cone at the end of the nozzle, and/or from a plurality of compartments into which the treatment end of the nozzle is divided (stage 240).

[0067] In the above description, an embodiment is an example or implementation of the invention.

The various appearances of "one embodiment", "an embodiment", "certain embodiments" or "some embodiments" do not necessarily all refer to the same embodiments.

[0068] Although various features of the invention may be described in the context of a single embodiment, the features may also be provided separately or in any suitable combination. Conversely, although the invention may be described herein in the context of separate embodiments for clarity, the invention may also be implemented in a single embodiment. [0069] Certain embodiments of the invention may include features from different embodiments disclosed above, and certain embodiments may incorporate elements from other embodiments disclosed above. The disclosure of elements of the invention in the context of a specific embodiment is not to be taken as limiting their used in the specific embodiment alone.

[0070] Furthermore, it is to be understood that the invention can be carried out or practiced in various ways and that the invention can be implemented in certain embodiments other than the ones outlined in the description above.

[0071] The invention is not limited to those diagrams or to the corresponding descriptions. For example, flow need not move through each illustrated box or state, or in exactly the same order as illustrated and described.

[0072] Meanings of technical and scientific terms used herein are to be commonly understood as by one of ordinary skill in the art to which the invention belongs, unless otherwise defined.

[0073] While the invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the preferred embodiments. Other possible variations, modifications, and applications are also within the scope of the invention. Accordingly, the scope of the invention should not be limited by what has thus far been described, but by the appended claims and their legal equivalents.

Claims

CLAIMS What is claimed is:

1. A plasma treatment device comprising a nozzle configured to receive a first gas and an auxiliary gas and direct a flow thereof towards a treatment end of the nozzle, and at least one electrode configured to apply a radiofrequency (RF) electromagnetic (EM) field on at least a part of a volume enclosed by the nozzle, the RF EM field configured to ionize at least part of the received first gas, to emit plasma at the treatment end of the nozzle.

2. The plasma treatment device of claim 1, further comprising:

a chamber within the nozzle, the chamber configured to receive at least part of the auxiliary gas, and

at least one second electrode configured to apply a RF EM field within the chamber to ionize at least part of the auxiliary gas, to emit plasma thereof from the chamber into the nozzle.

3. The plasma treatment device of claim 1, wherein the nozzle comprises a central constriction configured to introduce the auxiliary gas into the received first gas utilizing the Venturi effect.

4. The plasma treatment device of any one of claims 1-3, wherein the auxiliary gas comprises at least one of oxygen, nitrogen and air,

5. The plasma treatment device of claim 1, wherein the nozzle has an increasing cross section toward the treatment end.

6. The plasma treatment device of claim 5, wherein the at least one electrode is spirally wrapped around the nozzle with an increasing diameter.

7. The plasma treatment device of claim 1, further comprising a member within the nozzle, the member configured to move the at least one electrode.

8. The plasma treatment device of claim 1, wherein the at least one electrode comprises a plurality of concentric electrodes.

9. The plasma treatment device of claim 8, wherein at least the treatment end of the nozzle is divided into compartments which correspond to respective concentric electrodes.

10. The plasma treatment device of claim 1, wherein the at least one electrode comprises a branched electrode that spans the treatment end of the nozzle.

11. The plasma treatment device of claim 10, wherein the branched electrode is configured to be rotatable.

12. The plasma treatment device of claim 10, further comprising a rotating shield having at least one opening and positioned between the branched electrode and the treatment end of the nozzle.

13. The plasma treatment device of claim 1, further comprising a perforated treatment end cover.

14. The plasma treatment device of any one of claims 1-13, wherein the treatment end has an area of at least 1 cm².

15. The plasma treatment device of claim 1, wherein the treatment end comprises peripheral pores configured to emit the plasma laterally with respect to the nozzle.

16. The plasma treatment device of claim 1, wherein the treatment end comprises a plurality of concentric cones, each having peripheral pores configured to emit the plasma laterally with respect to the cones.

17. The plasma treatment device of any one of claims 1-16, wherein the first gas comprises at least one of helium and argon.

18. A method comprising:

configuring a nozzle to receive first gas and an auxiliary gas and direct a flow thereof towards a treatment end of the nozzle, and

applying a RF EM field to ionize at least part of the received first gas, to emit plasma at a treatment end of the nozzle.

19. The method of claim 18, further comprising applying a RF EM field within the nozzle to ionize at least part of the auxiliary gas, to emit plasma thereof into the nozzle.

20. The method of claim 18, further comprising applying the RF EM field within the nozzle to gradually increase a spatial extent of the generated plasma.

21. The method of claim 18, further comprising introducing the auxiliary gas into the received first gas by the Venturi effect.

22. The method of claim 18, further comprising emitting the plasma out of the treatment end of the nozzle at least: at an area perpendicular to the flow direction in the nozzle, at a periphery of the nozzle, laterally from at least one cone at the end of the nozzle, and from a plurality of compartments into which the treatment end of the nozzle is divided.

23. The method of claim 18, further comprising applying the RF EM field using a rotating branched electrode.

24. The method of claim 23, further comprising partially shielding the rotating electrode from the treatment end.

25. A plasma treatment device comprising a nozzle configured to receive a gas and direct a flow thereof towards a treatment end of the nozzle, and at least one electrode configured to apply a radiofrequency (RF) electromagnetic (EM) field on at least a part of a volume enclosed by the nozzle, the RF EM field configured to ionize at least part of the received gas, to emit plasma at the treatment end of the nozzle, wherein the nozzle has an increasing cross section toward the treatment end.

26. A plasma treatment device comprising a nozzle configured to receive a gas and direct a flow thereof towards a treatment end of the nozzle, and at least one electrode configured to apply a radiofrequency (RF) electromagnetic (EM) field on at least a part of a volume enclosed by the nozzle, the RF EM field configured to ionize at least part of the received gas, to emit plasma at the treatment end of the nozzle, wherein the at least one electrode is spirally wrapped around the nozzle with an increasing diameter.

27. A plasma treatment device comprising a nozzle configured to receive a gas and direct a flow thereof towards a treatment end of the nozzle, and at least one electrode configured to apply a radiofrequency (RF) electromagnetic (EM) field on at least a part of a volume enclosed by the nozzle, the RF EM field configured to ionize at least part of the received gas, to emit plasma at the treatment end of the nozzle, wherein the at least one electrode comprises a plurality of concentric electrodes.

28. A plasma treatment device comprising a nozzle configured to receive a gas and direct a flow thereof towards a treatment end of the nozzle, and at least one electrode configured to apply a radiofrequency (RF) electromagnetic (EM) field on at least a part of a volume enclosed by the nozzle, the RF EM field configured to ionize at least part of the received gas, to emit plasma at the treatment end of the nozzle, wherein the treatment end comprises peripheral pores configured to emit the plasma laterally with respect to the nozzle.

29. The plasma treatment device of claim 28, configured as an inner part of an anastomosis-treating device configured to emit the plasma peripherally and circularly.

30. A film made of biocompatible material selected to enhance tissue treatment by plasma welding, the film comprising holes configured to drain wound fluids.

31. The film of claim 30, further comprising air bubbles configured to enhance the treatment.

32. The film of claim 30 or 31, wherein the film is formed as an elongated strip and further comprising attached adhesive tape on at least one long side of the elongated strip, the film further comprising at least one reinforced zone of pre-heated film material.

33. The film of any one of claims 30-32, further comprising at least one of: antiseptics, antibiotics, plasma-activated compounds, at least one compound selected to release free radicals upon exposure to the plasma, silver, silver salts and silver acetylate.