Preventing fog on medical device viewport

Abstract

To provide methods of immunizing a viewport of a medical device against fogging before or during a medical procedure, and related apparatuses and devices.SOLUTION: The viewport may be a viewport of a medical device 200 such as an endoscope and the process of immunization may be provided before using the medical device 200 in a medical procedure. The method comprises applying a plasma-generating electromagnetic field in a closed chamber that houses the viewport, in close vicinity to the viewport. The plasma treatment of the viewport is configured to increase hydrophilicity so as to achieve complete wetting of the viewport by water.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention, in some embodiments, relates to the field of medical devices having viewports, such as endoscopes, and more particularly, but not exclusively, to methods and devices for preventing the accumulation of fogging in viewports of medical devices during medical procedures. [Background technology]

[0002] Endoscopes are widely used in medical procedures, particularly minimally invasive surgical procedures. Here, "endoscope" is meant to include any scope having a distal end configured to be inserted into a patient's body and a proximal end configured to remain outside the patient's body during the procedure. Generally, the distal end includes a viewport, such as a lens or window, or the bare end of an optical fiber, or even a mirror (e.g., like a dentist's scope). Through the viewport, the scope allows for the collection of an image of the area around the viewport using a light-sensitive device, such as a CCD. The viewport can be aimed to collect light from the front of the device (i.e., from an area coincident with the longitudinal axis of the device), or the viewport can be tilted at an angle relative to the longitudinal axis or can face perpendicular to the longitudinal axis of the device (e.g., as shown in colonoscopy). The proximal end generally includes or is coupled to a handle held by the practitioner, possibly including user interface components, such as switches, a navigation stick, a touchscreen, and a touchpad.

[0003] Endoscopes include a wide range of scopes, such as bronchoscopes, colonoscopes, cystoscopes, and laparoscopes. A laparoscope—by way of example—consists of a rigid or relatively rigid rod or shaft having a viewport, possibly including an objective lens at the distal end, and an eyepiece and / or integrated visual display at the proximal end. Scopes may also be connected to a remote visual display device or a video camera for recording the surgical procedure.

[0004] In a laparoscopic procedure, the patient's abdominal or pelvic cavity is accessed through one or two or more relatively small incisions (generally about 3 mm to about 15 mm), and a laparoscope is inserted through one of the incisions to allow the practitioner to view the internal organs to be operated on. The abdomen is usually insufflated with gas using an insufflator (carbon dioxide is usually used for inhalation) to expand the abdominal space by elevating the abdominal wall above the internal organs, thereby creating sufficient working and viewing space for the surgeon.

[0005] The local environment within the patient's abdominal space is typically moist and warm compared to the laparoscope being inserted, and therefore the laparoscope viewport tends to become obscured, for example, by fogging, i.e., by condensation of steam on the viewport, or by the accumulation of liquid droplets, such as blood droplets resulting from surgical work during the procedure.

[0006] Some existing techniques used to clean the viewport of an endoscope require withdrawing the endoscope from the patient's body, rinsing or wiping the viewport (e.g., with a cloth), and possibly drying and gently advancing the distal tip to reduce or delay the formation of fogging after the endoscope is returned to the patient's body. Other existing techniques involve rinsing the viewport inside the patient's body. U.S. Patent No. 8,047,215 discloses a laparoscope lens cleaner suitable for maintaining laparoscope lenses clean and dry during laparoscopic surgical procedures. An embodiment of the laparoscope lens cleaner includes an elongated cleaner barrel having an interior barrel, a fluid conduit provided in the cleaner barrel, a fluid discharge nozzle provided in the interior barrel and in communication with the fluid conduit, a gas conduit provided in the cleaner barrel, and a gas discharge nozzle provided in the interior barrel and in communication with the gas conduit. U.S. Patent Application Publication No. 20150005582 discloses a method for defog-cleaning a laparoscope. The method includes inserting a laparoscope into a sheath, inserting the laparoscope and sheath into a body cavity, supplying gas to a plurality of gas lumens within a wall of the sheath such that the gas flows through the gas lumens and over the lens of the laparoscope to defog the lens while the laparoscope is in the body cavity, and supplying a fluid containing a surfactant to the fluid lumens within a wall of the sheath such that the fluid flows through the fluid lumens and over the lens to clean the lens while the laparoscope is in the body cavity. Summary of the Invention

[0007] Aspects of the present invention, in some embodiments thereof, relate to eliminating fogging—i.e., reducing or preventing fogging and clouding—on viewports of medical devices. More particularly, aspects of the present invention, in some embodiments thereof, relate to methods and devices for preventing the accumulation of fogging on viewports of medical devices during medical procedures.

[0008] As noted above, there are existing techniques for keeping the viewport of a medical device clean during a medical procedure in which the medical device is used within a patient's body. These techniques involve active cleaning of the viewport by removing the medical device from the patient's body and cleaning the viewport with a cloth or rinse, or by rinsing the viewport within the patient's body (and perhaps drying it using a gas stream), and are therefore suboptimal. Interrupting the medical procedure for cleaning can result in a longer procedure time and can further lead to various complications arising from mental upset for the practitioner or from performing a procedure step that is not normally medically necessary. Withdrawing the medical device from the patient's body to perform cleaning is even worse; thus, removal and reintroduction of the device into the body can cause further complications.

[0009] One reason that blurring can occur due to vapor condensation on a viewport is that the condensing liquid—for example, water, perhaps mixed with bodily fluids—condenses into droplets that distort the light rays passing through them, thereby compromising the optical quality of the viewport. In other words, each droplet may act as a lens, focusing, diverging, or generally distorting the light rays passing through it in uncontrolled directions. The net effect of multiple droplets on a viewport thus creates an optically uneven surface, thereby preventing a clear image from being obtained from the light passing through (or reflected from) the viewport. [Means for solving the problem]

[0010] Thus, according to some embodiments, a method for preventing fogging of a viewport during use is provided. According to some embodiments, the viewport can be a viewport of a medical device, such as an endoscope, and the preventative treatment can be applied prior to using the medical device in a medical procedure. The method includes applying a plasma-generating electromagnetic field in a closed chamber housing the viewport in close proximity to the viewport. The plasma treatment of the viewport is configured to increase hydrophilicity to achieve complete wetting of the viewport by water. Complete wetting is achieved by increasing the surface tension of the treated surface of the viewport above that of water, i.e., above 0.072 N / m. Preferably, the surface tension of the viewport surface exceeds 0.08 N / m, and is raised to above 0.1 N / m for a limited period of time after plasma treatment, as described above. When the surface tension of the treated surface of the viewport is greater than that of water, water does not accumulate in droplets on the surface but rather wets the surface, having a contact angle of substantially 0 degrees. Thus, because condensation of water on the hydrophilic surface of the viewport results in a thin, uniform layer of fluid, this method eliminates or at least significantly reduces fogging, thereby maintaining or at least limiting the degradation of the optical quality of the viewport. Fluid thickness variations on the viewport are reduced by the plasma treatment, and thereby optical length variations associated with the passage of light through condensed fluid on the viewport are likewise reduced.

[0011] The effect of plasma treatment on the hydrophilicity of the treated surface is often temporary, and as a result, the hydrophilicity of the treated surface tends to decrease over time after exposure to the plasma has ceased. This method thus further includes using the viewport (or the device to which the viewport is attached) shortly after applying the plasma—i.e., exposing the viewport to moisture. "Shortly after" means using the viewport within 24 hours, preferably within 6 hours, and more preferably within 1 hour after applying the plasma to it.

[0012] It is noted that, according to the teachings herein, the plasma is generated in a dielectric barrier discharge (DBD) mode to ensure uniformity of the plasma-generating electric field near the viewport and, therefore, to ensure the quality of the plasma treatment. Herein, the "quality" of the plasma treatment refers to the level of hydrophilicity achieved and the duration for which the electric field is activated to achieve that hydrophilicity. In other words, a high-quality plasma treatment achieves a relatively high level of hydrophilicity (e.g., achieving a surface tension on the treated surface that exceeds that of water, i.e., greater than 0.072 N / M) within a relatively short period of time (e.g., 5 minutes, or 1 minute, or as short as 10 seconds, or even as short as 5 seconds of the activated electric field).

[0013] Plasma generation in DBD mode can be achieved, for example, by electrically isolating one of the electrodes used to apply the field. This type of isolation can be achieved by a dielectric layer that separates the electrode from the gas in the region where the plasma is generated, or DBD mode can be achieved, for example, by a dielectric layer that blocks the line of sight between two electrodes to which the plasma-generating field is applied. For example, according to some embodiments, a dentist's mirror can be treated in accordance with the teachings herein by placing the distal end of the device, including the mirror with, for example, a metal handle portion, in a nearby chamber, electrically connecting the cathode to the metal handle, and applying an RF high voltage to the anode, which is electrically isolated from the gaseous medium surrounding the mirror. According to other exemplary embodiments, a viewport made of a dielectric material, such as glass or plastic, and having no metal components around it can be treated in accordance with the teachings herein by being placed between two exposed electrodes used to apply the plasma-generating field, so that the viewport itself serves as a dielectric barrier by blocking the line of sight between the electrodes.

[0014] Generating the plasma in DBD mode as described herein allows the electrodes to be positioned at a relatively short distance from each other and from the surface being treated, keeping the electric field relatively uniform in the viewport near the surface being treated, and applying a relatively strong field, thereby providing a high quality plasma treatment to the surface being treated ("relatively" is used herein in comparison to generating the plasma in a non-DBD mode).

[0015] According to some embodiments, there is further provided an apparatus for preparing an endoscope for endoscopy, the apparatus comprising a protective shroud sized to receive a distal end of the endoscope therein, the distal end comprising a viewport configured to allow an image of a region surrounding the viewport to be collected therethrough. The apparatus further comprises a plasma-generating field applicator having a slot configured to electrically connect to a power source and to receive therein the distal end of the endoscope surrounded by the protective shroud. The plasma-generating field applicator is configured to apply an electric field within the slot suitable for plasma generation proximate the viewport. The protective shroud is detachable from the distal end of the endoscope and from the plasma-generating field applicator.

[0016] According to some embodiments, the protective shroud comprises at least one electrode and at least one shroud electrical contact configured to electrically contact a corresponding applicator electrical contact of the plasma-generating field applicator when the protective shroud is inserted into the slot, the at least one electrode configured to apply a plasma-generating field within the protective shroud upon receiving power thereby from the plasma-generating field applicator.

[0017] According to one aspect of some embodiments, a method of preparing an endoscope for endoscopy is provided, comprising providing a protective shroud therein sized to receive the distal tip of the endoscope. The distal tip includes a viewport configured to allow collection of an image of the area surrounding the viewport through the protective shroud. The method further comprises providing a plasma-generating field applicator, wherein the protective shroud is detachable from the distal tip and from the plasma-generating field applicator. The plasma-generating field applicator has a slot configured to electrically connect to a power source and receive the distal tip of the endoscope enclosed by the protective shroud therein. The plasma-generating field applicator is configured to apply power suitable for plasma generation within the protective shroud. The method further comprises placing the distal tip of the endoscope enclosed by the protective shroud within the slot of the plasma-generating field applicator and activating the power source to generate plasma within the protective shroud, thereby plasma treating the viewport at the distal tip. According to some embodiments, the method further comprises preventing contamination of the plasma-generating field applicator by fluid dispersed at the distal tip with the protective shroud.

[0018] According to an aspect of some embodiments, there is also provided a method of preparing an endoscope for endoscopy. The endoscope includes a distal end having a viewport. The viewport is made of a dielectric material and is closest to a metal portion at the distal end of the endoscope. The method includes placing the distal end of the endoscope in a plasma chamber having at least an anode and a cathode, where the cathode is in electrical contact with the metal portion. A line of sight between the anode and the cathode is blocked by a dielectric barrier, and the method further includes applying a plasma-generating electromagnetic field between the anode and the cathode, thereby generating a DBD mode plasma in the vicinity of the viewport. According to some embodiments, the electrical barrier electrically isolates the anode from gas in the vicinity of the viewport.

[0019] According to some embodiments, the viewport is transparent, such as a laparoscope viewport. According to some embodiments, the viewport is a mirror, such as a dentist's mirror. According to some embodiments, the viewport is made of glass, quartz, or plastic.

[0020] This invention separately provides an apparatus that can be used to plasma treat a viewport of a medical instrument, such as an endoscope, to activate the exterior surface of the viewport to obtain a surface tension of the exterior surface that is higher than the surface tension of water.

[0021] The present invention separately provides a method of preparing a medical instrument having a viewport, such as an endoscope, for a medical procedure by plasma treating the viewport to make it highly hydrophilic, thereby preventing fogging of the viewport during use.

[0022] The present invention separately provides a method of preparing a medical device for a medical procedure, either immediately prior to or even during the procedure. The present invention also provides an apparatus configured to apply plasma treatment to a medical device, such as an endoscope, in a clean and sterile environment, either immediately prior to or even during the procedure.

[0023] Particular embodiments of the present invention may include some, all, or none of the above advantages. Additional advantages may be readily apparent to those skilled in the art from the figures, descriptions, and claims included herein. Aspects and embodiments of the present invention are further described below in the present specification and in the appended claims.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the patent specification, including definitions, will control. As used herein, unless the context clearly dictates otherwise, the indefinite articles "a" and "an" mean "at least one" or "one or more."

[0025] Some embodiments of the present invention are described herein with reference to the accompanying drawings. The description, together with the drawings, will make apparent to those skilled in the art how some embodiments can be implemented. The drawings are for illustrative purposes, and no attempt is made to show structural details of the embodiments in more detail than is necessary for a fundamental understanding of the present invention. For clarity, some objects depicted in the drawings are not to scale. [Brief explanation of the drawings]

[0026] [Figure 1A] 1 diagrammatically illustrates an embodiment of an apparatus for preparing a medical device for a medical procedure in accordance with the teachings herein; [Figure 1B] 1B is a diagrammatic representation of the distal end of an endoscope, the distal end comprising a viewport suitable for plasma treatment by the apparatus of FIG. 1A. [Figure 1C] 1B is a schematic representation of the sterility screen of the device of FIG. 1A with a sterility sleeve for covering the plasma applicator of the device of FIG. 1A, the sterility sleeve being rolled up prior to use. [Figure 1D] 1D is a schematic representation of the sterility screen of FIG. 1C, in which the sterility sleeve is partially expanded to cover the plasma applicator. [Figure 1E] 1D is a schematic representation of the sterility screen of FIG. 1C, in which the sterility sleeve is unfolded, thereby covering the plasma applicator. [Figure 2] 1A and 1B are diagrammatic representations of an embodiment of a protective shroud of an apparatus for preparing a medical device for a medical procedure in accordance with the teachings herein, the protective shroud surrounding an endoscope to be plasma treated. [Figure 3A] 10 is a diagram illustrating a protective shroud positioned within a slot in a plasma applicator of the apparatus. [Figure 3B] 3B is a schematic representation of a detail of the protective shroud of FIG. 3A; [Figure 3C]10 is a diagrammatic representation of another embodiment of a protective shroud and generated field applicator for preparing a medical device for a medical procedure in accordance with the teachings herein. [Figure 4] 10 is a diagrammatic representation of yet another embodiment of a protective shroud for a device for preparing a medical device for a medical procedure in accordance with the teachings herein; DETAILED DESCRIPTION OF THE INVENTION

[0027] The principles, uses, and implementations of the teachings herein may be better understood with reference to the accompanying description and figures. Upon review of the description and figures herein, one skilled in the art will be able to practice the teachings herein without undue effort or experimentation. In the figures, like reference numerals refer to like parts throughout.

[0028] FIG. 1A diagrammatically illustrates an apparatus 100 for preparing a medical device 200, such as an endoscope, for a medical procedure, according to some embodiments. The medical device 200 includes a distal end 210, also diagrammatically illustrated in FIG. 1B. The distal end 210 includes a viewport 220 configured to allow collection of an image of the area surrounding the viewport. The viewport 220, in some embodiments, can be a transparent sheet, such as a window or lens, made of a material such as glass or quartz, or a plastic such as Perspex, thereby allowing light from outside the medical device 200 to be collected inside the medical device 200 by a light-sensing device (not shown here), such as a camera. According to some embodiments, the viewport 220 can be a mirror that reflects light toward (rather than transmits light through) a light-collecting device (not shown here) or a light-sensing device. The viewport 220 includes a surface 222 that may be exposed to moisture during a medical procedure. Thus, if not treated, e.g., prevented, from fogging, surface 222 can become covered with fogging. This type of fogging is the result of the accumulation of liquid droplets on surface 222 due to, for example, but not limited to, vapor condensation.

[0029] The apparatus 100 includes a protective shroud 110 sized to receive the distal end 210 of the medical device 200 therein. The apparatus 100 further includes a manipulation unit 120 and a plasma applicator 130 (also referred to herein as a plasma-generating electric field applicator) connected to the manipulation unit 120. The plasma applicator 130 includes a slot 132 configured to receive the distal end 210 of the medical device 200 therein, while the distal end 210 is surrounded by the protective shroud 110. In other words, for use, the distal end 210 of the medical device 200 is inserted into the protective shroud 110, and the protective shroud 110, with the distal end 210 surrounded therein, is inserted into the slot 132. According to some embodiments, the protective shroud 110 is inserted into the slot 132, and then the distal end 210 is inserted into the protective shroud 110 and advanced.

[0030] According to some embodiments, the device 100 further includes a sterility screen 140 having an opening 142. For use, the protective shroud 110 is inserted into the slot 132 through the opening 142 in the sterility screen 140, as described and explained further herein below. According to some embodiments, the protective shroud 110 is a non-critical, disposable, or replaceable part, configured for use during a single medical procedure performed on a single patient. According to some embodiments, the protective shroud functions as a sterility barrier between the endoscope, which may be exposed to a patient's bodily fluids, and the plasma applicator, which may or may not remain sterile during and after use. According to some embodiments, the sterility screen 140 facilitates maintaining the plasma applicator 130 free of bodily fluids originating from the endoscope during and after use. According to some embodiments, the sterility screen 140 facilitates maintaining the endoscope sterile against contamination that may originate from the plasma applicator 130.

[0031] According to some embodiments, the sterility screen 140 is attached to a sterile sleeve 144, as shown diagrammatically in FIGS. 1C, 1D, and 1E, with the sterile sleeve extending between the sterility screen and a distal end 146 of the sleeve. According to some embodiments, the sterile sleeve 144 can be soft, like a sock. Prior to use, the sterile sleeve 144 can be folded, as shown diagrammatically in FIG. 1C. For use, the sterile sleeve 144 can be expanded to surround, enclose, and cover the plasma applicator 130, or a portion thereof, by inserting the plasma applicator into the sterile sleeve through the distal end 146 of the sleeve. During use, the sterile sleeve 144 can be positioned around the plasma applicator 130 to surround and cover the plasma applicator 130, so that insertion through the opening 142 in the protective shroud 110 into the slot 132 and / or insertion of the endoscope 200 into the protective shroud 110 cannot contaminate the plasma applicator 130. According to some embodiments, the sterile sleeve can be substantially rigid, e.g., tubular in shape, and configured to house the protective shroud therein. According to some embodiments, the sterile sleeve 144 includes a double-sided adhesive pad (not shown here) at its bottom that can be secured to the plasma applicator 130 on one side and to a desk, table, or other work platform on the other side, thereby attaching and stabilizing the plasma applicator to the work platform and facilitating insertion and removal of the protective shroud 110 (or endoscope 200) from the plasma applicator 130. According to some embodiments, the sterile screen 140 together with the sterile sleeve 144 is attached to the protective shroud 110, so that the insertion of the protective shroud 110 into the slot 132 and the encapsulation of the plasma applicator 130 with the sterile sleeve 144 are performed substantially together.

[0032] The plasma applicator 130 is electrically connected to a power supply (not shown here), which may optionally be located in the operating unit 120. When the distal end 210, surrounded by the protective shroud 110, is positioned within the slot 132, and upon activation of the power supply, the plasma applicator 130 is further configured to apply an electric field suitable for plasma generation proximal to the viewport 222 within the protective shroud 110 within the slot 132.

[0033] According to some embodiments, the plasma applicator 130 can be fluidly coupled to a gas pump and, additionally or alternatively, to a gas tank (neither shown here). The gas pump and gas tank can be used to controllably evacuate or controllably flush the area around the distal end of the endoscope with a suitable gas, respectively, to facilitate plasma ignition, as described in further detail below. According to some embodiments, the suitable gas can be argon or nitrogen. According to some embodiments, a gas pressure suitable for plasma ignition after evacuation can be 0.1 Atm or less. According to some embodiments, the area around the distal end of the endoscope can be pumped, evacuated, and then flushed with the desired gas. According to some embodiments, the gas pump and / or gas tank can optionally be located in the operational unit 120.

[0034] The operation unit 120 is configured to allow a user of the device 100 to operate and control the device. The operation unit 120 may therefore comprise command switches and controllers, e.g., physical or virtual switches, buttons, and controllers. The control unit may further comprise indicators for providing the user with data and information required to operate the device, e.g., display LEDs, displays, and / or operation software for providing the user with operation and command screens to enable the user to operate and command the device.

[0035] 2 diagrammatically depicts an embodiment of a protective shroud 310 in cross section, according to aspects of some embodiments. The protective shroud 310 is particularly suited for use with an endoscope 380, which is diagrammatically depicted by a dotted line within the protective shroud 310. The endoscope 380 comprises a distal tip 382 and an electrically conductive surface, e.g., a metal surface 384, at the distal end 382 proximal to a viewport 390. The viewport 390 further comprises an exterior surface 392 that can be subjected to plasma treatment as described herein.

[0036] Protective shroud 310 comprises a hollow cylindrical body 312 extending between a proximal opening 314 and a cylindrical distal end 316. Protective shroud 310 further comprises a vacuum seal 320 including three O-rings 320a, 320b, and 320c, respectively. Vacuum seal 320 is configured to fit the external dimensions (e.g., outer diameter) of endoscope 380 so that endoscope 380 can be inserted into protective shroud 310 using little force, for example, by hand, as is known in the art. Vacuum seal 320 is thus configured to maintain a pressure differential (or gas concentration difference) between an interior 322 of protective shroud 310 and an exterior 324 of protective shroud 310 when endoscope 380 is disposed within protective shroud 310. The vacuum seal 320 can also help mechanically stabilize the endoscope 380 within the protective shroud 310, thereby helping to prevent gas leakage between the interior 322 and exterior 324, and also assists in plasma generation proximate the viewport 390, as further described below.

[0037] The protective shroud 310 further comprises a cathode 330 disposed in the hollow cylindrical body 312 and configured to establish an electrical feedthrough between the exterior 324 of the protective shroud 310 and its interior 322. The cathode 330 is flexible and electrically exposed to the interior 322 of the protective shroud 310, thereby forming an electrical contact between the cathode 330 and a metal surface 384 and enabling insertion of an endoscope 380 into the protective shroud 310. The protective shroud 310 further comprises an anode 340 disposed proximate the cylindrical distal end 316. The anode 340 can be shaped, for example, as a metal block having a circular, smooth surface 342 facing the interior 322. According to some embodiments, the surface 342 can be curved. According to some embodiments (not shown here), the anode 340 can be shaped as a pointed tip pointing toward the interior 322. According to some embodiments, the anode 340 can be shaped as a ring. The anode 340 is attached to a disk 344 made of a dielectric material such that the disk 344 forms a dielectric barrier between the anode 340 and the cathode 330 and the metal surface 384 of the endoscope (which is at the same potential as the cathode). In other words, the disk 344 is configured to ensure plasma generation in a dielectric barrier discharge (DBD) mode of operation by blocking the line of sight between the anode 340 and the cathode 330 and the metal surface 384 of the endoscope, thereby forming the dielectric barrier. In the DBD mode, the plasma can be generated more uniformly throughout the space available near the viewport, but arcing or other types of specific thin electrical transport trajectories between the anode and cathode are prevented.

[0038] It should be noted that the thickness of the dielectric barrier strongly influences the uniformity of the plasma-generating electric field near the viewport and, therefore, the quality of the plasma treatment. Herein, the "quality" of a plasma treatment refers to the level of hydrophilicity achieved and the duration of the electric field activation required to achieve that hydrophilicity. In other words, a high-quality plasma treatment achieves a relatively high level of hydrophilicity (e.g., achieving a surface tension on the treated surface that exceeds that of water, i.e., greater than 0.072 N / M) within a relatively short period of time (e.g., 5 minutes of field activation, or as short as 1 minute or 10 seconds, or as short as 5 seconds). The thickness of the dielectric barrier should generally be as small as possible to facilitate plasma ignition, yet large enough to prevent breakdown and arcing. Typical thicknesses of dielectric materials, such as PET or polycarbonate in the embodiments described herein, can range from about 0.3 mm to about 3 mm for RF electric fields with frequencies in the MHz range (e.g., about 2 MHz).

[0039] According to some embodiments, the anode 340 is configured for flexible movement relative to the hollow cylinder 312 to facilitate reliable electrical contact between the anode 340 and a supply contactor, as described further below. According to some embodiments, the disk 344 can be supported relative to the hollow cylinder 312 by a spring 346.

[0040] In operation, plasma-generating power is supplied between the anode 340 and the cathode 330, so that a DBD mode plasma-generating electric field is generated between the anode 340 and the metal surface 384 in contact with the cathode 330. The plasma-generating electric field generates a plasma in the space between the anode 340 and the cathode 330, and particularly adjacent the exterior surface 392 around the viewport 390.

[0041] 3A schematically illustrates a portion of an embodiment of a plasma applicator 348 suitable for use with a protective shroud 310a (which differs slightly from the protective shroud 310 of FIG. 2, as described in more detail below). The plasma applicator 348 includes a slot 350 configured to receive the protective shroud 310a therein (where the endoscope 380 is surrounded by the protective shroud 310a). The plasma applicator 348 further includes a cathode contactor 352 configured to contact the cathode 330 when the protective shroud 310a is within the slot 350. An electrical conductor 354, such as an electrical wire, electrically coupled to the cathode contactor 352 can be used to supply electrical power generated by a power source (not shown) to the cathode contactor 352 and, in turn, to the cathode 330. The plasma applicator 348 further includes an anode contactor 356 configured to contact the anode 340 when the protective shroud 310a is in the slot 350. An electrical conductor 358, such as an electrical wire, electrically coupled to the anode contactor 356 can be used to supply power generated by a power supply to the anode 340. The anode contactor 356 can be flexibly supported, for example by a spring 360, to facilitate reliable electrical contact between the anode contactor 356 and the anode 340 when the protective shroud 310a is inserted into the slot.

[0042] It should be noted that the characteristics of the electric field capable of generating a gas plasma can depend strongly on the characteristics of the gas itself, as well as the electrode geometry involved (e.g., the shape and configuration of the electrodes used to apply the electric field, the distance between the electrodes, etc.). Typically, the higher the gas pressure, the higher the electric field must be to ignite a gas plasma. Also, some gases ignite at lower electric fields than others. For example, plasma can be ignited in helium gas at atmospheric pressure using an RF electric field of about 7 kV (at a frequency between 1 MHz and 15 MHz) across a 1 cm distance between the electrodes, and at a voltage of about 200 V when the gas is at a pressure of 0.8 kPa. For similar electrode geometries and similar field frequencies, plasma can be ignited in air at a voltage of about 20 kV at atmospheric pressure and about 800 V at 0.8 kPa.

[0043] Thus, according to some embodiments, plasma applicator 348 is configured to flow gas from a gas tank (not shown) into slot 350 or pump air through slot 350 to generate a low-pressure atmosphere in the space between electrodes 330 and 340 to facilitate plasma ignition. Thus, according to some embodiments, plasma applicator 348 is connected to a hose 364 that is fluidly coupled to a gas tank (not shown) containing a gas suitable for plasma generation therein, such as helium, argon, or nitrogen, along with slot 350. A valve 366 controlled by a user-operable control unit (not shown) can be used to schedule and regulate the gas flow entering slot 350. During operation, according to some embodiments, after protective shroud 310a with endoscope 380 therein is introduced into slot 350, valve 366 can be opened to allow gas flow into the slot. The protective shroud 310a allows gas flow through the opening 368 between the hollow cylinder 312 and the disk 344, allowing gas to enter the protective shroud 310a and flow toward the viewport 390. Excess gas that enters the slot 350 is free to escape through the gap in the slot 350 between the protective shroud 310a and the plasma applicator 348 (the gap is not sealed). After an appropriate period of gas flow (e.g., 5 seconds, 10 seconds, 30 seconds, or 1 minute), the power supply can be activated to supply power to the anode 340 and cathode 330 to generate a plasma-generating electric field near the viewport 390. According to some embodiments, the gas tank can be portable and suitable for single use.

[0044] According to some embodiments, hose 364 can be used to pump gas (air) from the protective shroud 310a, particularly from the space near viewport 390, to facilitate plasma ignition. Air can be drawn from the periphery of viewport 390 through opening 368, toward slot 350, and into hose 364. Vacuum seal 370 allows for a vacuum to be created near viewport 390 by maintaining a pressure differential between the area near cylinder end 316 and the area near opening 314 in protective shroud 310a. According to some embodiments, air can be pumped through hose 364 by a vacuum pump (not shown) fluidly coupled to hose 364. According to some embodiments, hose 364 can be fluidly coupled to a pumping vessel (not shown) that is continuously pumped, for example, by a miniature vacuum pump. A fluid connection is provided through hose 364, so that the hose is in constant fluid communication with the vessel and is also continuously pumped thereby. Opening valve 366 can result in pumping out the space near slot 350 and particularly viewport 390 by a vacuum pump or a pumping container, depending on the particular embodiment. The volume of the pumping area of ​​slot 350 and the fluidly connected portion of protective shroud 310a can be less than 10 cc, according to some embodiments; for example, a pumping container and hose of about 1000 cc (1 liter) can be sufficient to establish an appropriate vacuum level, for example, between about 0.1 atmospheres and about 0.01 atmospheres, in less than about 5 seconds or less than about 10 seconds, which can be sufficient for about 30 seconds or even about 1 minute of plasma excitation to satisfactorily plasma treat exterior surface 392.

[0045] 3B , according to some embodiments, the protective shroud 310a further comprises a sterile filter 372 positioned at the opening 368 to maintain a sterility barrier between the protective shroud 310a and the plasma applicator 348. By maintaining a sterility barrier, it is meant that bacterial microorganisms cannot penetrate the sterile filter 372, which can include any type of prokaryotic or eukaryotic cell, including fungi and bacteria. The sterile filter, according to some embodiments, is positioned over the cylindrical end 316 of the opening 368 so that gases entering the protective shroud 310a from the plasma applicator 348 enter the sterile protective shroud, and / or gases entering the plasma applicator 348 from the interior 322 of the protective shroud 310a enter the sterile plasma applicator. In this manner, the sterile filter 372 prevents the transfer of contaminants from the plasma applicator (e.g., from the environment of the slot 350) to the endoscope 380 and / or prevents the transfer of contaminants from the endoscope 380 to the plasma applicator. Additionally or alternatively, a sterile filter can be located on the plasma applicator or, for example, on the hose 364.

[0046] 3C diagrammatically depicts a plasma applicator 448 and a corresponding protective shroud 410 according to some example embodiments. The plasma applicator 448 differs from the plasma applicator 348 in that the plasma applicator 448 includes an applicator gas port 402 fluidly coupled to the hose 364, and the protective shroud 410 includes a shroud gas port 404 configured to fluidly couple to the applicator gas port 402. Fluid connectivity between the interior 322 of the protective shroud and the exterior 324 of the protective shroud 410—e.g., the space of the plasma applicator slot 450—is prevented by a vacuum seal 408, e.g., an O-ring. As such, when the protective shroud 410 is inserted into the plasma applicator 448, the shroud gas port 404 fluidly couples to the applicator gas port 402, thereby establishing fluid connectivity of the hose 364 to the interior 322 of the protective shroud. Thus, plasma ignition promoting gas (e.g., helium or argon) can be admitted directly to the protective shroud through hose 364; additionally or alternatively, gas, particularly air, can be pumped out of the protective shroud through hose 364. Fluid connectivity between slot 450 and the interior 322 of the protective shroud is thus prevented. A sterile filter 472 is disposed within shroud gas port 404 to maintain a sterile barrier between the interior 322 of the protective shroud 410 and the plasma applicator 448. As discussed above with respect to sterile filter 372 in FIG. 3B , gas flowing from the plasma applicator 448 into the interior 322 of the protective shroud 410 enters the sterile protective shroud, and / or gas flowing from the interior 322 of the protective shroud 410 into the plasma applicator 448 enters the sterile plasma applicator. In this manner, the sterile filter 472 prevents the transfer of contamination from the plasma applicator (eg, from around the slot 450) to the endoscope 380 and / or prevents the transfer of contamination from the endoscope 380 to the plasma applicator.

[0047] The protective shroud 410 further differs from the protective shroud 310 by having a ring anode 440 shaped as a ring on the outer circumference of the hollow cylinder 312 near the distal cylindrical end 316 (instead of the anode 340 of the protective shroud 310). The hollow cylinder 312, therefore, made of a dielectric material, acts as a dielectric barrier 444 between the anode 440 and the cathode 330 and the metal surface 384 of the endoscope, so that a plasma is generated in the protective shroud 410 in the DBD operating mode as described above with respect to the protective shroud 310. According to some embodiments, the protective shroud 410 includes a stopper 442 within the hollow cylinder 412. The stopper 442 is configured to limit the advancement of the endoscope 380 into the protective shroud 410 so that a predetermined desired gap is established between the anode 440 and the metal surface 384 of the endoscope, thereby ensuring plasma generation at a known electric field (the electric field is determined by the cathode and the voltage supplied between the anode and the gap). The stopper 442 can further be used as a line-of-sight dielectric barrier between the anode and cathode, thereby helping to focus the plasma toward the viewport 390.

[0048] When the protective shroud 410 is inserted into the slot 450 of the plasma applicator 448, the anode contactor 456 of the plasma applicator 448 contacts the ring anode 440. The anode contactor 456 is electrically coupled to an electrical conductor 458 configured to connect to a power source (not shown here) to enable a plasma-generating electric field to be supplied to the ring anode 440 as described above. It is noted that when the protective shroud 410 is inserted into the slot 450 as described above, the cathode 330 of the protective shroud 410 is electrically coupled to the cathode contactor 352. Thus, upon activation, a suitably connected power source can supply a plasma-generating electric field (in DBD mode) between the ring anode 440 and the metal surface 384 of the endoscope 380 to generate plasma in the vicinity of the viewport 390.

[0049] 4 diagrammatically illustrates a protective shroud 510 according to one aspect of some embodiments. The protective shroud 510 is configured to allow for enhanced plasma ignition around the endoscope without pumping gas out of the space around the endoscope and without allowing gas to flow into the space, as described in the previous embodiments. In other words, the protective shroud allows for plasma treatment to be applied to the endoscope viewport in accordance with the teachings herein using a plasma applicator that is not connected to a gas tank or gas pump. Thus, the protective shroud does not have a gas port, such as gas port 402, and is not connected to a hose, such as hose 364.

[0050] The protective shroud 510 comprises a hollow cylindrical body 312 extending between an opening 314 and a cylindrical end 316. The protective shroud 510 differs from the protective shroud 310 in that the hollow cylindrical body 312 has no outlet and is sealed near the cylindrical end 316, thereby substantially preventing the penetration or infiltration of gas molecules through the cylindrical end 316. The protective shroud 510 further differs from the protective shroud 310 in that it includes a leak seal 530 within the hollow cylindrical body 312 and a sealing screen 518 on the hollow cylindrical body 312 between the leak seal 530 and the cylindrical end 316. The sealing screen 518 is configured to be impermeable to gas molecules, thereby defining a closed, enclosed volume 520 between the sealing screen 518 and the cylindrical end 316. The enclosed volume 520 within the protective shroud 510 is thus airtight, i.e., maintained sealed from the exterior 324 of the protective shroud 510. The enclosed volume 520 contains a gas suitable for plasma ignition, for example argon, at a gas pressure of about 1 atmosphere, so that there is, at most, only a small pressure gradient across all the sealing screens.

[0051] The sealing screen 518 is frangible and configured to break (break) upon insertion of an endoscope, such as endoscope 380, into the protective shroud 510. According to some embodiments, the protective shroud 510 further comprises one or more tearing needles 522 flexibly attached to the hollow cylindrical body 312 near the sealing screen 518 outside the enclosed space 520. The tearing needles 522 are configured to flexibly lean against the sealing screen 518 and tear the sealing screen when pushed by an object inserted into the protective shroud. Thus, for use, an endoscope can be inserted into the protective shroud 510 and affect the breaking of the sealing screen 518 by pushing the tearing needles 522 toward the sealing screen 518. The endoscope can be further advanced until the viewport is between the cathode 330 and the anode 340. It is noted that during insertion, the endoscope is first advanced through leak seal 530, then the sealing screen 518 is breached, and then the endoscope is advanced further so that it is in place. Once the sealing screen 518 is breached, gas within space 520 is prevented from freely flowing toward opening 324 by the seal formed between leak seal 530 and the endoscope. During further advancement of the endoscope into the protective shroud 510, the free volume of space 520 for gas decreases, yet pressure buildup in the region of closed space 520 is prevented by gas leakage under the pressure differential across leak seal 530. As a result, when endoscope 380 is fully inserted into the protective shroud 510, closed space 520, and particularly the space proximal to the viewport, between anode 340 and cathode 330, is at approximately atmospheric pressure and substantially contains the gas contained in space 520 prior to the breach of sealing screen 518, thereby facilitating plasma ignition therein. According to some embodiments, the sealing screen 518 can be made of Mylar or metallized Mylar or Kapton or metallized Kapton or the like.

[0052] Thus, according to an embodiment of the present invention, there is provided an apparatus (100, FIG. 1A) for preparing an endoscope (200, FIG. 1; 380, FIGS. 2, 3A, and 3C) for endoscopic examination. The apparatus includes a protective shroud (110, FIG. 1A; 310, 310a, FIGS. 2 and 3A; 410, FIG. 3C; 510, FIG. 4) sized to receive the distal end (210, 382) of the endoscope therein. The distal end includes a viewport (220, 390) configured to allow collection of an image around the viewport therethrough.

[0053] The apparatus further includes a plasma-generating field applicator (130, 348, 448) electrically coupled to the power source. The plasma-generating field applicator has a slot (132, 350, 450) configured to receive the distal end of the endoscope surrounded by a protective shroud. The plasma-generating field applicator is configured to apply electrical power suitable for generating plasma within the protective shroud. The protective shroud is detachable from the distal end of the endoscope and from the plasma-generating field applicator.

[0054] According to some embodiments, the viewport of the endoscope can be transparent or can be a mirror.

[0055] According to some embodiments, the device further comprises a sterile sleeve (144) extending between the first end (146) and the second end (140) configured to encapsulate the plasma-generating field applicator, the sterile sleeve having a first opening at the first end configured to allow insertion of the plasma-generating field applicator into the sterile sleeve and a second opening (142) at the second end configured to allow insertion of an endoscope into the plasma-generating field applicator. According to some embodiments, the sterile sleeve is flexible, and according to some embodiments, the sterile sleeve is rigid. The sterile sleeve is separate from the plasma-generating field applicator. According to some embodiments, the sterile sleeve is attached to a protective shroud, and according to some embodiments, the sterile sleeve is separate from the protective shroud.

[0056] According to some embodiments, the protective shroud includes at least one electrode (340, 440) and a first shroud electrical contact (340, 440) electrically connected to the electrode. The first shroud electrical contact is configured to make electrical contact with a corresponding first applicator electrical contact (356, 456) of the plasma-generating field applicator when the protective shroud is inserted into the slot (350, 450). The at least one electrode is configured to apply a plasma-generating field within the protective shroud interior (322) upon receiving power thereby from the plasma-generating field applicator.

[0057] According to some embodiments, the protective shroud further comprises a second shroud electrical contact (330) configured to contact the endoscope when the distal end of the endoscope is received within the protective shroud and configured to make electrical contact with the second applicator electrical contact (352) when the protective shroud is inserted into the slots (350, 450).

[0058] According to some embodiments, the protective shroud comprises a hollow, substantially rigid tube (312, 412) extending between an opening (314) configured to receive the distal tip of the endoscope and the distal end (316) of the protective shroud. According to some embodiments, the hollow tube is a hollow cylinder (312, 412).

[0059] According to some embodiments, the protective shroud further comprises a seal (320, 530) disposed along the inner circumference of the hollow tube between the opening and the distal end, sized to surround the endoscope (380) and configured to make sealing contact with the endoscope when the endoscope is received within the hollow tube. According to some embodiments, the seal comprises an O-ring.

[0060] According to some embodiments, the plasma-generating field applicator (348, 448) is coupled to a hose (364). The hose is controllably fluidly coupled to the slot (350, 450). According to some embodiments, the plasma-generating field applicator (348, 448) comprises a control valve (366) that controllably fluidly couples the hose (364) to the slot (350, 450). According to some embodiments, the plasma-generating field applicator (348) comprises an applicator gas port (402) fluidly coupled to the hose, and the protective shroud (410) comprises a shroud gas port (404). The shroud gas port is configured to sealingly couple with the applicator gas port to fluidly couple the hose with the interior (322) of the protective shroud. A sealed connection between the shroud gas port and the applicator gas port, for example by seal 408, prevents fluid communication between the interior (322) of the protective shroud (which fluidly couples with hose 364) and the slot (450) when the protective shroud is inserted into the slot.

[0061] According to some embodiments, the protective shroud (510) comprises a seal (530) configured to make sealing contact with the endoscope inside the hollow tube (312) when the distal end of the endoscope is inserted into the hollow tube. The protective shroud (510) further comprises a sealing screen (518) configured to traverse the hollow tube, thereby defining a closed, sealed space (520) between the sealing screen and the distal end (316) of the hollow tube. According to some embodiments, the protective shroud further comprises a pliers (522) disposed within the hollow tube between the seal (530) and the sealing screen (518) and configured to tear the sealing screen upon insertion of the endoscope into the hollow tube.

[0062] According to one aspect of some embodiments, a method of preparing an endoscope for endoscopy is provided. The method includes providing a protective shroud (110, 310, 310a, 410, 510) sized to receive a distal end (210, 382) of the endoscope therein, the distal end including a viewport (220, 390) configured to allow collection of an image around the viewport therethrough. The method further includes providing a plasma-generating field applicator (130, 348, 448) electrically coupled to a power source. The plasma-generating field applicator has a slot (132, 350, 450) configured to receive the distal end of the endoscope surrounded by the protective shroud therein. The plasma-generating field applicator is configured to apply power (e.g., via electrodes 330, 340, and 440) suitable for plasma generation within the protective shroud. The protective shroud is detachable from the plasma-generating field applicator and from the distal end of the endoscope. The method further includes placing the distal end of the endoscope, surrounded by a protective shroud, in a slot of the plasma-generating field applicator and activating a power source to generate plasma within the protective shroud, thereby plasma treating a viewport at the distal end of the endoscope.

[0063] According to some embodiments, the method further includes preventing contamination of the plasma-generating field applicator by fluid dispersing at the distal tip with a protective shroud. According to some embodiments, the plasma-generating field applicator comprises a hose (364), and the method further includes controllably flowing gas into or pumping gas out of the interior of the protective shroud (322) through the hose (by opening and closing a valve 366).

[0064] According to an aspect of some embodiments, there is also provided a method of preparing an endoscope (380) for endoscopy, the endoscope comprising a distal end (382) with a viewport (390). The viewport is made of a dielectric material and is proximal to a metal portion (384) at the distal end of the endoscope. The method includes placing the distal end of the endoscope in a closed plasma chamber (e.g., a protective shroud 310, 310a, 410, or 510, where insertion of the endoscope seals an interior 322 of the protective shroud, thereby defining a closed plasma chamber therein). The closed plasma chamber has at least an anode (340, 440) and a cathode (330), where the cathode is in electrical contact with the metal portion. The line of sight between the anode and cathode is interrupted by a dielectric barrier (344, 444), and the method further includes applying a plasma-generating electromagnetic field between the anode and the cathode, thereby generating a DBD mode plasma in the vicinity of the viewport (322). According to some embodiments, the electrical barrier (444) electrically isolates the anode (440) from the gas in the vicinity of the viewport (322). According to some embodiments of this method, the viewport is transparent or alternatively a mirror. According to some embodiments of this method, the viewport is made of glass, quartz, or plastic.

[0065] It will be appreciated that certain features of the invention that are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, features of the invention that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or in any other described embodiment of the invention, as appropriate. A feature described in the context of an embodiment should not be considered an essential feature of that embodiment unless expressly identified as such.

[0066] Although the steps of the methods according to some embodiments may be described in a particular sequence, the methods of the present invention may include some or all of the described steps performed in a different order. The methods of the present invention may include all of the described steps or only a few of the described steps. No particular step in a disclosed method should be considered an essential step of the method unless reasonably clearly identified.

[0067] While the present invention has been described in connection with specific embodiments thereof, it is evident that numerous variations, modifications, and variations thereof, which will be apparent to those skilled in the art, may exist. Accordingly, the present invention encompasses all such variations, modifications, and variations that fall within the scope of the appended claims. It is to be understood that the invention is not necessarily limited in its application to the details of construction and arrangements of parts and / or methods set forth herein. Other embodiments may be practiced, and certain embodiments may be carried out in various ways.

[0068] The phraseology and terminology used herein is for descriptive purposes only and should not be considered limiting. Citation or identification of any reference in this application should not be construed as an admission that such reference is available as prior art to the present invention. Headings are used herein to facilitate understanding of the specification and should not be construed as necessarily limiting.

Claims

1. 1. A method of preparing an endoscope for endoscopy, the endoscope having a distal end with a viewport made of a dielectric material attached to a metal portion, the method comprising: placing the distal end of the endoscope in a closed plasma chamber having at least an anode and a cathode, the cathode in electrical contact with the metal portion, a line of sight between the anode and the cathode being blocked by a dielectric barrier, the method further comprising applying a plasma generating electromagnetic field between the anode and the cathode, thereby generating a dielectric barrier discharge (DBD) mode plasma around the viewport.

2. The method of claim 1 , wherein the dielectric barrier electrically isolates the anode from a gas surrounding the viewport.

3. The method of claim 1 , wherein the viewport is a mirror.

4. The method of claim 1 , wherein the viewport is made of glass, quartz, or plastic.

5. 5. The method of claim 4, wherein the dielectric material has a thickness in the range of 0.3 mm to 3 mm for an RF field at a frequency between 1 kHz and 100 MHz.

6. 5. The method of claim 4, wherein the dielectric material has a thickness in the range of 0.3 mm to 3 mm for an RF field at a frequency of 2 MHz.

7. The method of claim 1 , wherein the anode is shaped as a metal block having a circular, smooth surface.

8. The method of claim 1 , wherein the anode is shaped as a metal block having a curved surface.

9. The method of claim 1 , wherein the anode is shaped as a pointed tip or ring.

10. The method of claim 1 , wherein the anode is mounted on a disk.

11. The method of claim 10 , wherein the disk is made of a dielectric material.

12. The method of claim 11 , wherein the disk forms a dielectric barrier between the anode and the cathode and metal portions of the endoscope.

13. The method of claim 1 , wherein the endoscope is advanced until the viewport is between the cathode and the anode.

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