Abstract
A device for cold plasma endoscopy may include a cold plasma generating system, a catheter and electrically conductive means. The cold plasma generating system includes a gas source, an electrical source, a dielectric chamber, a first electrode surrounding the dielectric chamber and electrically connected to the electrical source. The catheter has a first lumen for carrying the cold plasma fluidly connected to the dielectric chamber at a proximal end and having an opening at a distal end for delivering the cold plasma. The electrically conductive means extend inside the first lumen. The electrical source is configured to apply a pulsed excitation signal to the first electrode. The device includes remotely actuated deployable confinement means for creating a confined space, wherein the opening of the first lumen is arranged in the confined space, the deployable confinement means allowing for confining the plasma substantially within the confined space.
Claims
1. A device for cold plasma treatment, the device comprising: a cold plasma generating system comprising: a gas source, an electrical source, and a cold plasma chamber comprising: a dielectric chamber fluidly connected to the gas source, a first electrode surrounding at least partially the dielectric chamber and electrically connected to the the electrical source; a catheter having a proximal end and a distal end, the catheter comprising a first lumen for carrying the cold plasma, the first lumen being fluidly connected to the dielectric chamber at the proximal end and having an opening at the distal end for delivering the cold plasma; and an electrical conductor extending inside the first lumen substantially from the dielectric chamber to the distal end, wherein the electrical source is configured to apply a pulsed excitation signal to the first electrode, and wherein the device comprises a remotely actuated deployable confinement system configured to create a confined space, wherein the opening of the first lumen is arranged in the confined space, wherein the deployable confinement system is configured to confine the plasma substantially within the confined space.
2. The device according to claim 1, wherein the pulsed excitation signal comprises pulses having a pulse width between 1 ns and 1 μs.
3. The device according to claim 1, wherein the pulsed excitation signal has a pulse frequency between 300 Hz and 100 kHz.
4. The device according to claim 1, wherein the electrical conductor is electrically insulated from the first electrode.
5. The device according to claim 1, wherein the electrical conductor is an electrically conductive wire or strip.
6. The device according to claim 1, wherein the catheter further comprises a second lumen adjacent to the cold plasma carrying lumen for carrying a gas to the catheter distal end, wherein the device comprises a gas source fluidly coupled to the second lumen, the gas source comprising one or more of the following gases: O.sub.2, He, CO.sub.2, and H.sub.2O vapor.
7. The device according to claim 1, wherein the confinement system comprises a first confinement system portion configured to seal a proximal cross section of a cavity and a second confinement system portion configured to seal a distal cross section of the cavity, wherein the confined space is arranged between the first and second confinement system portions.
8. The device according to claim 7, wherein the first confinement system portion and the second confinement system portion are inflatable balloons.
9. The device according to claim 7, wherein the first confinement system portion is configured to be arranged at a proximal side of the distal end of the catheter, and wherein the second confinement system portion is configured to be arranged at a distal side of the distal end of the catheter.
10. The device according to claim 1, further comprising deployment means operably coupled to the deployable confinement system for remotely actuating the deployable confinement system, wherein the catheter comprises a third lumen for carrying the deployment means.
11. The device according to claim 10, wherein the deployment means comprise: a fluid source or a cable.
12. The device according to claim 1, wherein the distal end of the catheter further comprises dispensing means fluidly connected to the first lumen configured to distribute radially a cold plasma transported by the first lumen.
13. The device according to claim 12, wherein the dispensing means comprises at least two holes, the at least two holes being configured for distributing the cold plasma transported by the first lumen in a direction essentially radial to a direction tangent to the first lumen at the catheter distal end.
14. A cold plasma endoscopic system comprising the device according to claim 1 and an endoscope.
15. The cold plasma endoscopic system according to claim 14, wherein the endoscope comprises an operating channel, and wherein the catheter is configured to be received in the operating channel.
16. The cold plasma endoscopic system according to claim 14, further comprising deployment means operably coupled to the deployable confinement system for remotely actuating the deployable confinement system, wherein the endoscope further comprises a third lumen configured to receive the deployment means.
17. The device according to claim 7, wherein the opening of the first lumen is positioned between the first and the second confinement system portion.
18. A method for plasma treatment within a cavity of a human body, comprising: providing the device according to claim 1; deploying the deployable confinement system in the cavity, so as to create a confined space in the cavity; generating a gas flow from the gas source through the dielectric chamber and the first lumen and applying a pulsed electric potential to the first electrode for generating a plasma in the dielectric chamber; and transporting the generated plasma through the first lumen by the gas flow to the confined space.
19. The method of claim 18, comprising sealing a proximal cross section of the cavity by a first confinement means portion and a distal cross section of the cavity by a second confinement means portion, wherein the confined space extends from the proximal cross section to the distal cross section.
20. The method of claim 18, wherein the cavity is a cavity of a gastrointestinal tract.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0101] These aspects of the present disclosure as well as others will be explained in the detailed description of specified embodiments of the present disclosure, with reference to the drawings in the figures, in which:
[0102] FIG. 1 shows an exemplary embodiment of a device for plasma treatment according to aspects of the present disclosure;
[0103] FIG. 2 shows an exemplary embodiment of the plasma endoscopic system according to aspects of the present disclosure;
[0104] FIG. 3a-3c shows exemplary embodiments of the first flexible tube or of the catheter according to the present disclosure;
[0105] FIG. 4a, 4b show exemplary embodiments of the device according to aspects of the present disclosure;
[0106] FIG. 5a-5f show exemplary embodiments of the dispensing means of the device according to aspects of the present disclosure;
[0107] FIG. 6a, 6b show exemplary embodiments of the dispensing means of the device according to aspects of the present disclosure;
[0108] FIG. 7a-7e show exemplary embodiments of the dispensing means of the device according to aspects of the present disclosure;
[0109] FIG. 8a-8c show exemplary embodiments of the dispensing means of the device according to aspects of the present disclosure;
[0110] FIG. 9a-9c show exemplary embodiments of the dispensing means of the device according to aspects of the present disclosure;
[0111] FIG. 10 shows exemplary embodiments of the confinement means of the device according to aspects of the present disclosure;
[0112] FIG. 11a-11c show exemplary embodiments of the confinement means of the device according to aspects of the present disclosure;
[0113] FIG. 12a-12d show exemplary embodiments of the confinement means of the device according to aspects of the present disclosure;
[0114] FIG. 13, 14 show exemplary embodiments of the confinement means of the device according to aspects of the present disclosure;
[0115] FIG. 15, 15b, 16 show exemplary embodiments of the confinement means of the device according to aspects of the present disclosure;
[0116] FIG. 17 shows oxidative coloring of agarose gel samples treated by pulsed plasma and by sinusoidal plasma for different generator output power levels immediately after plasma treatment;
[0117] FIG. 18 shows the gel samples of FIG. 17 one hour after plasma treatment.
[0118] The drawings in the figures are not to scale. Generally, similar elements are designated by similar reference signs in the figures. The presence of reference numbers in the drawings is not to be considered limiting, even when such numbers are also included in the claims.
DETAILED DESCRIPTION
[0119] FIG. 1 shows an exemplary embodiment of the device 100 for plasma endoscopy according to the present disclosure. The device 100 comprises a plasma generating system 10 that is connected to a gas supply connected to a gas source 11. The gas flow of the gas source 11 is controlled to deliver a gas flow of about 0.5 to 5 L/min. The plasma generating system 10 comprises a dielectric chamber 14 into which the gas from the gas source 11 flows. For example the dielectric chamber 14 is a quartz cylinder closed at its two ends by two fluidic connections to the gas source 11 and to the first flexible tube 20. The dielectric chamber 14 is at least partially surrounded by a first electrode 15. For example said first electrode 15 is a conductive tape or pieces of conductive tape. For example the first electrode 15 is formed around the dielectric chamber 14. The first electrode 15 is electrically connected to an electrical source 12 and preferably to a voltage source. The first electrode 15 is connected to a voltage source such that the voltage source 12 is configured to vary the electric potential of said first electrode 12. For example the voltage source 12 is a pulsed voltage source that delivers voltage pulses having a voltage amplitude higher than 1 kV, more preferably higher than 3 kV and even more preferably higher than 5 kV, and with a pulse width comprised between 1 ns to 1 μs in the kHz range. In FIG. 1, the electrical source or voltage source is grounded as well as a second electrode positioned at least partially in contact with the dielectric chamber 14. When a high potential is applied to the first electrode, a dielectric barrier discharge occurs and the gas in the dielectric chamber is ionized into a cold plasma. Said plasma is an atmospheric plasma since it is formed at a nearly atmospheric pressure. With the gas flow generated by the gas source 11, the plasma flows toward the first flexible tube 20 into the first lumen 25 where it is transported until a first flexible tube end.
[0120] In FIG. 1, an electrically conductive means 27 is placed in said first lumen 25. Preferably, the electrically conductive means 27 is placed partially inside the dielectric chamber 14 but not in a portion of the dielectric chamber 14 surrounded by the first electrode 15. The electrically conductive means 27 goes inside the first lumen 25, in contact with the plasma that flows inside the first lumen 25. The electrically conductive means 27 are placed until approximatively the end of the first lumen 25. For example the electrically conductive means are positioned so that they end between 2 cm before the first lumen 25 end to 1 cm after, preferably between 1 cm before to 0.5 cm after and even more preferably between 0.5 cm before and 0 cm after. In FIG. 1, the device 100 is shown when functioning, the generated plasma inside the dielectric chamber is represented by the grey shades between the first electrode 15 and the proximal end of the electrically conductive means 27 and at the exit of the first flexible tube 20 by the plume in a grey shade. An analysis of the emission intensity of the plasma during its generation shows that the emission intensity is much lower all along the electrically conductive means 27, in this case a copper wire having a diameter of 0.2 mm. Then when the plasma exits the first lumen 25, with the copper wire stopping between 1 cm and 0 cm, preferably 5 mm before the end of the first lumen 25, the plasma turns ON, with an intensity similar to the intensity observed in the dielectric chamber 14, between the first electrode and the proximal end of the copper wire. A plurality of positioning means could be used to mechanically couple the electrically conductive means inside the first lumen 25 in order that it has a fixed proximal end and a fixed distal end regarding the dielectric chamber and the lumen end respectively.
[0121] FIG. 2 shows a plasma endoscopy system 200 comprising the device 100 shown in FIG. 1. The plasma endoscopy system 200 comprises an endoscope and the device 100 according to FIG. 1. The endoscope shows a control section for controlling the endoscope functions and guidance. The endoscope also shows an instrument channel or working channel. The device 100 is connected at this position of the endoscope of the flexible tube 20 is inserted as a catheter inside said working channel of the endoscope in order to deliver a plasma at the endoscope distal end. The endoscope insertion tube 70 or endoscope 70 that can be inserted into a hollow body comprises an outer envelope defining the outer contour of the endoscope 70. It further shows a working channel used to carry the plasma through the plasma carrying lumen 28, the plasma carrying lumen 28 being formed into a catheter 60. The catheter is a flexible tube, i.e. a single-lumen catheter or a multi-lumen catheter.
[0122] FIG. 2 also shows another embodiment comprising a single tube fluidly connected to the plasma chamber 13 which allows to transport the generated plasma to the endoscope distal end 65. This single tube comprises the first tube 20 and the first lumen of the catheter 28. This single tube is preferably made in one single piece of tube, such that the first lumen 25 and the plasma carrying lumen 28 are within a single tube. As illustrated on FIG. 2, the conductive means 27 extends at least partially inside the single tube lumen.
[0123] FIGS. 3 a, 3b, and 3c show three examples of multi-lumen catheters 60 or flexible tube 20 that can be utilized within the scope of the present disclosure. A plasma carrying lumen 28 is represented delimited by inside surface 26. An electrically conductive means 27 is also represented in dashed lines when it is inside the catheter 60 or tube 20 and with a solid line when it is directly observable. On FIG. 3a, a second lumen 62 is represented for carrying a gas, a third lumen 63 is also represented for carrying deployment means, for example a deployment fluid or a cable. Other lumens shown can be kept available for improvement of the present disclosure. FIGS. 3b and 3c show a first 28 and a second 62 lumen having different shapes, depending on the ratio of plasma and gas to be delivered to the dispensing means 30. FIGS. 3b and 3c do not show a third lumen 63 for carrying deployment means because said deployment means can also be carried through a third lumen 63 located inside another catheter or through an over-tube fluidic connection. An over tube fluidic connection is shown on FIGS. 11a, 12a, and 16 where there is a gap between the endoscope 70 and an over tube wall.
[0124] FIG. 4a shows a schematic embodiment of the second aspect of the present disclosure. The first flexible tube 20 or the endoscope 60 having a first lumen 25 carries the plasma generated by the plasma generating system 10 to the dispensing means 30. As it is shown on FIG. 4a, the distal end 65 of the catheter 60 either ends at the same point than the distal end of the endoscope 75 as represented by the dotted lines of the endoscope 70 or the distal end 65 of the catheter 60 ends further to the distal end 75 of the endoscope 70. The dispensing means 30 are mechanically and fluidly connected to the distal end of the catheter 60. The electrically conductive means 27 extends inside said dispensing means in order to transport the plasma and to turn on the plasma again just before exiting said dispensing means 30. Preferably the electrically conductive means 27 is divided into many wire in order to radially distribute the plasma. For example the dispensing means 30 comprises a plurality of openings, therefore a plurality of electrically conductive means 27 extends in the direction of each of said openings.
[0125] FIG. 4b shows a chart showing many dispensing means 30 alternatives in a hierarchical way. The dispensing means 30 described in this chart are sought to allow an homogenous and radial distribution of the plasma into a hollow body. This chart can be read as follows: a dispensing means 30 can have multiple holes, one hole with moving (x-y) means, one or multiple holes with redirecting means or either only a longitudinal confinement means 40 also able to dispense radially the plasma. In the case of multiple holes, these holes can be located: [0126] around the walls of the dispensing means 30 (see FIG. 5); [0127] in a plan or in a curved surface (see FIG. 6); [0128] in a tube, the tube having different shapes and or tube subdivisions (see FIG. 7).
In the case of redirecting means (see FIG. 8) the plasma is redirected by a cap. In the case of moving (x-y) means, the plasma nozzle is or are rotated such as to dispense the plasma radially around a rotation axis (see FIG. 9). The plasma can also simply be dispensed homogenously in a hollow body thanks to confinement means 40 that allow plasma or reactive species to reach each point of the hollow body thanks to the plasma flow from said plasma carrying lumen 28.
[0129] FIG. 5 a shows a dispensing means 30 with at least two tubes fluidly connected to the plasma carrying lumen 28, these tubes are preferably self-expandable or having a pre-formed shape such that the plasma can be dispensed around the catheter 60 after self-expansion or after having retrieved said preformed shape. The self-expandability or ability to retrieve said preformed shape allows the tubes to deploy by itself. FIG. 5b shows a dispensing means 30 comprising a head into which a groove is formed, said groove being fluidly connected to said plasma carrying lumen 28. Said groove allowing to dispense a plasma coming from the plasma carrying lumen 28 all around the endoscope 70. The electrically conductive means 27 is shown within the plasma carrying lumen 28, which can be prolonged within said groove into multiple electrically conductive means, for example coated on the groove surface. FIG. 5c shows a head similar to the one of FIG. 5b, FIG. 5b is a perspective view while FIG. 5c being a cross-sectional view. Head of FIG. 5c comprising gas nozzles 621 within said groove of said head in order to provide gas from the second lumen 62. The gas nozzles 621 being fluidly connected to the second lumen 62. The plasma carrying lumen 28 is shown as well as the second lumen 62 adjacent to each other's within the catheter 60. The plasma shown by the grey shading can be seen to disappear after the gas from the second lumen 62 is injected. This is because the plasma has reacted with the gas from the second lumen in order to form reactive species. Preferably these reactive species are free radicals. Free radicals are preferably neutral. Therefore no emission spectrum can be observed from said reactive species. FIG. 5d shows a head with a plurality of diamonds openings around the radial surface of the head. Any other opening shapes can be used. Diamonds are here simply shown as an example, openings can be for examples, triangles, slits, squares, rectangles, polygons, holes, . . . . For example, there are between 4 to 16 diamonds holes all-around said radial surface. Preferably this dispensing mean 30 extends further to said endoscope and is mechanically coupled to the catheter 60. The electrically conductive means 27 extends within said head and preferably a plurality of electrically conductive means 27 extend to the opening of the radial surface of the head. Dispensing means 30 with a head being for example deployable or inflatable by means of a deployment fluid.
[0130] FIG. 5e and FIG. 5f show a same folded and unfolded dispensing means 30 respectively. This shown dispensing means 30 is similar to an inverted umbrella. The dispensing means comprises a plurality of rigid flexible tube like umbrella ribs fluidly connected to the plasma carrying lumen 28. The dispensing means 30 of FIG. 5e is deployed by pulling the distal part represented by a black disk on the right hand-side of the FIG. 5e to the center of the open ring shown on the right-hand side of FIG. 5e. The distal part of the dispensing means 30 is pulled to the proximal deployment mean (open ring) by a cable carried in said third lumen 63. On FIG. 5f, the plasma can then be dispensed radially to said endoscope, with a rigid umbrella structure. Such a dispensing can comprise between 4 to 12 umbrella like ribs for deploying and prolong the plasma carrying lumen 28.
[0131] FIG. 6a shows a dispensing means 30 where a watering can rose type of head is used to homogenously dispense the plasma. The plurality of holes is formed on a curved surface. A tangent of the curved surface in its center being perpendicular to the main direction of the catheter 60. Dozens of holes can be formed on said curved surface. FIG. 6b, shows a dispensing means 30 having a shower head type of dispensing means 30. The holes being formed on a flat or curved surface. A tangent to the center of the surface being parallel to the main direction of the catheter 60.
[0132] FIG. 7 show different variants of tubes with holes for dispensing the plasma. FIG. 7a shows a whisk, with each wire of the whisk being tubes fluidly connected to the plasma carrying lumen 28. Each whisk tube being perforated on its external surface in order to deliver the plasma radially. Preferably the whisk tubes are flexible such that it can easily be inserted into a hollow body. Such a dispensing means 30 comprises at least four tube whisks and for example 5, 6, 7, 8, 9, or 10. FIG. 7b shows a dispensing means 30 being a single tube prolonging the plasma carrying lumen 28 of the catheter 60. The tube being perforated with holes of diameter larger at the distal part of the tube than at its proximal part. The tube being blocked at its end. The increasing hole diameter when going toward the distal part allows to compensate pressure drop caused by the respective proximal holes. FIG. 7c is similar to FIG. 7b but the tube is coiled into a helicoidal shape. The tube is preferably blocked at its end. The holes are preferably formed on the external surface of the tube. FIG. 7d shows a branched like shape for dispensing the plasma in a hollow body. FIG. 7d dispensing means comprises branches elongating in the distal direction, each branch having a plurality of holes. Preferably an electrically conductive means 27 extends into each of said branches. FIG. 7e shows a similar dispensing means than in FIG. 7d but the branches are open ended with large holes, for example the diameter of the large holes is similar to the diameter of the plasma carrying lumen 28.
[0133] FIG. 8a, b, c show compact dispensing means 30 having a main opening fluidly connected to the plasma carrying lumen 28 in front of which a redirecting means is placed such that the flow of plasma exiting the opening hits the redirecting means and flows around it in order to be spread around it. FIG. 8a redirecting means is a ball, oval, round, sphere or ellipsoid. FIG. 8b is a cone, the top of the cone being oriented to the plasma flow. FIG. 8c redirecting means is a cylinder, preferably the cylinder having a diameter equal to that of the main opening.
[0134] FIG. 9 shows three embodiments of dispensing means 30 with a rotating part in order to distribute a plasma radially in an homogeneous way. FIG. 9a shows a curved tube that is rotatably mounted on said endoscope and fluidly connected to the plasma carrying lumen 28. Rotating means are provided through a lumen of the catheter of through a channel of the endoscope and is controlled on the control section of the endoscope 70. For example, rotating means are activated by twisting the part of the catheter that remains out of the endoscope into the practitioner hand. FIG. 9b shows a multiple tubes having at least three tubes fluidly connected to the plasma carrying lumen 28 allowing a similar dispersion of the plasma than FIG. 9a but with a lower rotating speed. FIG. 9c shows a straight tube with a single opening with an helix or a propeller rotatably mounted distally to the opening in order to spray around the plasma.
[0135] FIG. 10 shows a chart showing the confinement means 40 configurations envisaged by the inventors. The confinement means are described in detail in FIG. 11 to FIG. 16.
[0136] FIGS. 11a and 11b show a confinement means with one balloon. In FIG. 11a, the single balloon is positioned around the endoscope 70, allowing to have vision where the plasma is delivered. FIG. 11b shows a balloon positioned around said catheter 60, the catheter distal end 65 being distal to the balloon. In FIG. 11b, the balloon is over the catheter 60. The balloon of FIGS. 11a and 11b being inflatable by connecting them fluidly to the third lumen 63 and inflating them with a deployment means such N.sub.2, CO.sub.2, or air. FIG. 11c shows a schematic representation of FIG. 11a. In another embodiment, said third lumen 63 is another catheter or a flexible tubing next to the endoscope 70 and is not within the catheter 60.
[0137] FIG. 12 shows two balloons for confining a volume defined by walls and said balloons, said walls to be treated with the plasma or with reactive species generated by reaction with the plasma. The first balloon is a first confinement means portion 40a and the second balloon is a second confinement means portion 40b. The first balloon 40a of FIG. 12a and FIG. 12b is the same than the balloon of FIG. 11a and FIG. 11b respectively. The second balloon 40b is mechanically connected to the first balloon 40a in order to keep space between the balloons 40a, 40b. In FIG. 12a the mechanical connection is at least two filaments in which air can pass from the first to the second balloon such that both balloon can be inflated from the same deployment means, for example deployment means from the third lumen 63 or from another catheter/flexible tube. In FIG. 12b, the mechanical connection is at the level of the catheter 60 such that the third lumen 63 of the catheter can inflate both balloons. For example, in FIG. 12b, mechanical connections are at least two catheters such as in FIG. 12a. In FIG. 12b, the first balloon is over the endoscope 70. FIG. 12c shows a schematic view of FIG. 12a. FIG. 12d shows a schematic view of FIG. 12b, with in addition a dispensing means allowing a radial dispensing of the plasma.
[0138] FIG. 13 shows a confinement means 40 with an egg shape having opening in order to be able to treat a confined surface. The confinement means 40 of FIG. 13 comprises a first confinement means portion 40a being proximal and a second confinement means portion 40b being distal. The two portions 40a, 40b being mechanically coupled by filaments or ribs having a self-expandable or having a pre-formed shape such that the plasma can be dispensed around the catheter 60/endoscope 70 after self-expansion or after having retrieved said preformed shape. The self-expandability or ability to retrieve said preformed shape allows the two portions to deploy by itself. The endoscope distal end 75 and catheter distal end 65 being in between the two portions 40a and 40b such that vision is possible and plasma and gas delivery occur in the confined spaced. The two portions 40a, 40b being in a foldable material, the two portions 40a, 40b can be stretched by applying a higher pressure in between them, by means of the plasma flux or by means of the gas from the second lumen 62, or, by means of the auto/self-expandability of their constitutive material.
[0139] FIG. 14 shows a confinement means 40 with a cage chamber, the distal and proximal ends of the cage chamber being the a first confinement means portion 40a and a second confinement means portion 40b respectively. The cage comprises ribs made in a material being self-expandable or having a pre-formed shape, for example a material used for stents, i.e. self-expandable polymers such as polyesters. The distal 40a and proximal 40b ends being made in a foldable material such as a plastic foil or a coated mat, or a silicone (polysiloxanes). The catheter distal end 65 being positioned within said confined space between said distal 40a and proximal 40b ends. The ribs are preferably preformed and deployable. For example their deployment can be triggered by the deployment means from the third lumen 63, for example a cable or self-expandable (thanks to the elasticity of the material). This embodiment of FIG. 14 allows to treat a hollow surface at a desired position in an easy way and allows to displace within the hollow body the deployed confinement means 40 where the hollow body needs to be treated. Large surface area of hollow body to be treated can be reached in a relatively short time with the embodiment of FIG. 14. Thanks to this confinement means and dispersing means design, the dispersing means can be moved within the volume defined by the confinement means.
[0140] FIG. 15a shows a confinement means 40 being a flower type umbrella over the scope. This confinement means 40 can be deployed by means of inflating it or mechanically deploying it. FIG. 15b shows the same confinement means 40 than in FIG. 15a but instead of being over the endoscope 70, the confinement means 40 is deployed over the catheter 60.
[0141] FIG. 16 shows a confinement means that rely on suction of a portion of the mucosa in order to confine a portion of a hollow body. Suction can be carried out by means of holes located around the endoscope 70 and fluidly connected to the third lumen 63, said third lumen 63 being submitted to partial vacuum in order to create a mucosa suction. For this embodiment, said third lumen 63 being outside the endoscope as shown on FIG. 16. This embodiment can for example be combined with a distal balloon 40b as shown in FIG. 12a or FIG. 12b, the mucosa suction confinement means being a proximal confinement means 40a.
[0142] All the embodiments of dispensing means of FIGS. 3 to 9 and all embodiment of confinement means of FIG. 10 to FIG. 16 can be combined.
Experiments
[0143] The ability of a pulsed plasma to treat larger surface areas compared to a sinusoidal plasma was demonstrated by experiments on agarose gel. Agarose gel samples were prepared as described in Kawasaki et al., Applied Physics Express, vol. 9, no 7, pp. 1-5, 2016. This gel is mixed with a color indicator having the ability to change color from transparent to blue under oxidative conditions as created by a cold plasma irradiation. The gel was prepared by adding 0.6 g KI, 1 g potato starch and 1 g agarose in an Erlenmeyer flask of 200 mL, which was further filled with water. The flask was heated and agitated during 2 hours to dissolve the components. The obtained solution was subsequently poured in Petri dishes of 55 mm diameter (10 mL per dish measured with pipette) and left to solidify.
[0144] An AC power controlled generator was used for the sinusoidal plasma: AFS (G10S-V) coupled with an AFS 1-6 kHz electrical transformer and power controlled. For the pulsed plasma, a Megaimpulse nanosecond pulsed NPG-18/100 k generator was used. In both cases, a discharge chamber formed of a quartz tube with outer diameter of 7.2 mm and inner diameter of 4.9 mm wrapped in copper tape electrode was used. As plasma forming gas, helium (He) gas (Air Liquide) was used with a flow rate of 1.6 L/min.
[0145] In order to test a pulsed plasma at an equivalent power level of a sinusoidal plasma, the correct settings for the pulsed plasma were determined first on the generator. Parameter settings for the pulsed generator are the number of pulses per second (N) and pulse occurrence frequency (f), being the inverse of the (largest) time interval between consecutive pulses. For the pulsed plasma, the energy of one pulse Ep could be varied between 15 mJ (50% setting) and 30 mJ (100% setting). The plasma energy E was calculated by: E=Ep.Math.N. A continuous operation mode was assumed, meaning that the pulse occurrence frequency is equal to the number of pulses per second. The pulse width was 9 ns. Table 1 shows pulsed plasma settings and relating output power.
[0146] For each of the power levels of Table 1 (5, 10, 20, 30, 40, 50 and 60 W) 7 Petri dishes as prepared above were irradiated for 30 s with the pulsed plasma, and other 7 with a sinusoidal plasma at same power level. To this end, the plasma was conducted through a tube of 2.5 m length with outer diameter 3 mm and inner diameter 1 mm, provided with a conductor wire of 0.2 mm diameter at floating electric potential. The wire was positioned at 2 cm from the discharge electrode and extended until 0.5 cm inwards of the tube outlet. The tube outlet was maintained at about 1 cm from the gel surface. The results are shown in FIG. 17 showing coloring immediately after treatment. The dispersing effect of the pulsed plasma becomes even more evident form the photographs of FIG. 18, showing the dishes of FIG. 17 1 h after treatment. Clearly, for all power levels tested, the pulsed plasma caused a much larger colored zone, indicating a better spreading of the reactive plasma-excited species. This is true even at very small power levels. Furthermore, at 5 W, a plasma plume could be observed at the outlet of the pulsed plasma, but not for the sinusoidal plasma, and a coloring of the agarose gel could be observed for the pulsed plasma, but not for the sinusoidal plasma, proving better effectiveness of the pulsed plasma even at low power levels. From the pictures, it can be seen that the treatment zone of the sinusoidal plasma remains very localized until 60 W, while for the pulsed plasma, the treatment zone starts expanding as early as 10 W power level.
TABLE-US-00001 TABLE 1 Settings for pulsed plasma used in the experimets Power Pulse identifier Energy control energy Frequency Power used in (50% < x < 99%) (mJ) (Hz) N continuous (W) FIGS. 55 16.5 300 300 yes 4.95 5 W 55 16.5 600 600 yes 9.9 10 W 70 21 1000 1000 yes 21 20 W 99 29.7 1000 1000 yes 29.7 30 W 67 20.1 2000 2000 yes 40.2 40 W 83 24.9 2000 2000 yes 49.8 50 W 99 29.7 2000 2000 yes 59.4 60 W
[0147] The present disclosure has been described with reference to a specific embodiment, the purpose of which is purely illustrative, and they are not to be considered limiting in any way. In general, the present disclosure is not limited to the examples illustrated and/or described in the preceding text. Use of the verbs “comprise”, “include”, “consist of”, or any other variation thereof, including the conjugated forms thereof, shall not be construed in any way to exclude the presence of elements other than those stated. Use of the indefinite article, “a” or “an”, or the definite article “the” to introduce an element does not preclude the presence of a plurality of such elements. The reference numbers cited in the claims are not limiting of the scope thereof.
