Patent Description:
Various techniques are known to perform tissue ablation, commonly involving the use of a pulsed laser or RF energy.

US Patent Application Publication Number <CIT> discloses "A tissue ablation system includes an elongated shaft, such as a surgical probe shaft, and an needle electrode array mounted to the distal end of the shaft, and an ablation source, such as, e.g., a radio frequency (RF) generator, for providing ablation energy to the electrode array. The tissue ablation system further includes a heat sink disposed within the distal end of the shaft in thermal communication with the needle electrode array. In this manner, thermal energy is drawn away from the needle electrode array, thereby cooling the electrode array and providing a more efficient ablation process.

The tissue ablation system further comprises a coolant flow conduit in fluid communication with the heat sink, so that the thermal energy can be drawn away from the heat sink. In the preferred embodiment, the flow conduit includes a thermal exchange cavity in fluid communication with the heat sink, a cooling lumen for conveying a cooled medium (such as, e.g., saline at room temperature or below) to the thermal exchange cavity, and a return lumen for conveying a heated medium from the thermal exchange cavity. The tissue ablation system further comprises a pump assembly for conveying the cooled medium through the cooling lumen to the thermal exchange cavity at the distal end of the shaft.

<CIT>), entitled "Surgical Resection Device" is directed to a surgical organ resection device comprising a plurality of elongate electrodes for insertion into organ tissue. The electrodes are capable of operating in a bipolar manner. The device includes an input for receiving a drive signal for driving the electrodes with the elongate electrodes being arranged in a two-dimensional array. The device is arranged such that in use, subsets of the elongate electrodes are driven in turn.

<CIT>, entitled "Fractional Apparatus for Skin Beauty" is directed to a fractional apparatus including a main body and a hand piece. The main body includes a frequency-generating unit, for generating at least low-frequency, high-frequency or ultrasonic waves, and the hand piece is connected to the frequency-generating unit via a connection line, for transferring thermal energy to the inside of skin. Using the apparatus, needles are brought into contact with or inserted into the skin and are controlled by the operation of a motor. The hand piece includes upper and lower cases, which are detachably coupled together, and a connection unit, connected to the connection line and installed in the upper and lower cases to receive the frequency generated by the frequency-generating unit. The hand piece also includes a needle panel consisting of a plurality of needles and a fixing member to which the needles are fixed at a predetermined spacing, such that one end of each of the needles is connected to the connection unit and the other end of each of the needles is exposed outward from the lower case. The needle panel thus enables a predetermined length of each of the needles to contact or to be inserted into the skin.

<CIT>, entitled "Methods and Devices for Tissue Ablation" is directed to a device for vaporizing a hole in tissue. The device includes a vaporizing element, a heating element configured to heat the vaporizing element, and an advancing mechanism configured to advance the vaporizing element into a specific depth in the tissue. The advancing mechanism also retracts the vaporizing element from the tissue within a period of time long enough for the vaporizing element to vaporize the tissue yet short enough to limit diffusion of heat beyond a predetermined collateral damage distance from the hole.

<CIT>, entitled "Vacuum Insulated Cooling Probe with Heat Exchanger" is directed to an insulated cooling probe including a probe sleeve assembly having an annular insulating jacket shaped in the vicinity of an evacuation vent to achieve a deeper vacuum within the insulating space than is applied to the vent, and a coolant inlet passageway and a coolant exit passageway bounded by a coolant passageway wall disposed within the insulating jacket. The probe also includes a cooling tip extending outwardly from the sleeve assembly at one end of the probe and includes a cooling region into which coolant enters from the coolant inlet passageway and from which coolant exits into the coolant exit passageway. The coolant expands across an orifice upon exiting the coolant inlet passageway and upon entering the cooling tip. The coolant flowing in the coolant inlet passageway is pre-cooled in a heat transfer region of the probe by transferring heat to coolant flowing in the coolant exit passageway.

<CIT>, entitled "Thermal Resecting Loop" is directed to a thermal surgical instrument including a conductor having a ferromagnetic material in electrical communication with the conductor. The passage of electrical energy through the conductor is such that it causes substantially uniform heating of the ferromagnetic material to produce a desired therapeutic tissue effect. The conductor is shaped to facilitate resection of tissue from a patient and includes a support to provide increase rigidity to the loop so that the conductor better resists bending during use. The ferromagnetic material quickly heats and cools in response to a controllable power delivery source.

An article entitled "<NPL>, is directed to an evaluation of low-temperature diffusion of nickel through gold using Auger electron spectroscopy. The experimental setup involved printed-wiring-board fingers having a nickel diffusion barrier plated between a copper substrate and a cobalt-hardened gold surface contact. A coefficient of diffusion was determined which was one to two orders of magnitude smaller than the diffusion of copper under similar conditions. It was found that diffusion is the rate-limiting step in the accumulation of nickel at the gold surface.

An article entitled "<NPL>, is directed to an experimental study that characterized the heat affected zone of a Ti6Al4V alloy plate workpiece when laser heated. It was found that both the depth and the width of the heat affected zone were strongly dependent on the laser properties and the material properties. The depth and width of the heat affected zone increased with an increase in laser power and decreased with an increase in laser spot size and laser scan speed.

An article entitled "<NPL>, is directed to an investigation of the thermoelectric properties of nitrogen-doped TiO<NUM>-x containing oxygen defects. In the investigation, it was found that the formation of oxygen defects introduces electron carries, thus reducing the electrical resistivity of a TiO<NUM> compound which is intrinsically an insulating material. Further reduction of the electrical resistivity improved the thermoelectric power factor of the compound. It was also found that thermal conductivity was strongly reduced by phonon scattering at nanometer-spaced periodic planar defects of the Magneli phase crystallographic structure, thus resulting in the TiO<NUM> compound exhibiting good n-type performance at high temperatures.

An article entitled "<NPL>, is directed to a study of the influence of material composition on the structure and surface properties of bioactive coatings based on Cu and Ti. Thin films of various copper content were prepared and antimicrobial activity as well as cell viability were investigated. It was found that the prepared thin films were nanocrystalline and bactericidal, however their cytotoxicities were related to the Cu-content in the films.

Provided is a device according to claim <NUM>. According to an aspect of some embodiments of the invention there is provided a device for vaporizing at least one hole in tissue, comprising an array of vaporizing elements, one or more heating elements configured to heat the vaporizing elements, wherein a geometry of at least a portion of the vaporizing elements is configured to prevent excessive penetration of other vaporizing elements into the tissue. In some embodiments, the portion of vaporizing elements prevents excessive penetration of other vaporizing elements by having a leading surface area adapted for contact with the tissue that is larger than a leading surface area of the vaporizing elements which are prevented from excessively penetrating the tissue. In some embodiments, a distal tip of a vaporizing element that is shaped to prevent excessive penetration of a second vaporizing element is truncated. Optionally, the truncated vaporizing element is shorter than the second vaporizing element. Optionally, the second vaporizing element comprises a sharp distal tip. In some embodiments, the vaporizing elements are heated to a temperature ranging between <NUM>-<NUM> degrees Celsius. In some embodiments, the vaporizing elements are mounted on a plate. In some embodiments, a depth of penetration of at least a portion of the vaporizing elements with respect to a surface of the tissue is less than <NUM>. In some embodiments, the array produces a lesion pattern comprising a combination of deep and shallow craters in the tissue. In some embodiments, the array produces a plurality of craters in the tissue at a spatial distribution ranging between <NUM>-<NUM> craters/cm^<NUM>. In some embodiments, a length of a vaporizing element is larger than a base width of the vaporizing element by a factor smaller than <NUM>:<NUM> to prevent bending of the vaporizing element. Optionally, the device comprises pyramidal shaped vaporizing elements.

Optionally, the device comprises conical vaporizing elements. In some embodiments, the one or more heating elements are operable according to a heating protocol suitable for vaporizing tissue by the vaporizing elements. In some embodiments, the device is adapted for vaporizing a keratin layer in a nail by heating the keratin to a temperature higher than <NUM> degrees Celsius. In some embodiments, the device is adapted for exposing a surface of scar tissue for applying topical medication.

According to an aspect of some embodiments of the invention there is provided a device for vaporizing at least one hole in tissue, comprising an array of vaporizing elements, one or more heating elements configured to heat the vaporizing elements, the vaporizing element comprising at least one material selected to generate local vaporization and to reduce a damage region when the vaporizing element is heated to a temperature higher than <NUM>. Optionally, the material comprises a thermal conduction coefficient greater than <NUM> Watts per degree Kelvin per meter. In some embodiments, the material reduces diffusion in a second material when the vaporizing element is heated to a temperature higher than <NUM>. In some embodiments, the material and/or second material and/or a material coating the second material reduces IR emissivity towards the tissue. Optionally, the first material is silver or nickel, and the second material is copper. In some embodiments, a body of the vaporizing element is made of copper, and a nickel layer covers the copper. In some embodiments, the layers of copper and nickel are coated by a low IR emissivity layer made of gold.

According to an aspect of some embodiments of the invention there is provided a method for self-sterilizing an array of vaporizing elements, the array coupled to a heating element, comprising heating the vaporizing elements to a temperature higher than approximately <NUM> degrees Celsius to remove carbon residue from the vaporizing elements. In some embodiments, the vaporizing elements are heated to a temperature higher than approximately <NUM> degrees Celsius for a duration ranging between <NUM>-<NUM> seconds.

According to an aspect of some embodiments of the invention there is provided a device for vaporizing at least one hole in tissue, comprising a plurality of vaporizing elements arranged in an array; one or more heating elements configured to heat the vaporizing elements; wherein the array of vaporizing elements is adapted for moving in a cyclic movement profile, wherein the vaporizing elements are lowered and elevated repetitively to and from the tissue at an absolute acceleration rate that monotonically increases at least a long <NUM>% of the pathway of said vaporizing elements leading towards the tissue. Optionally, the increasing absolute acceleration rate reaches a maximal value upon contacting the tissue. In some embodiments, the array is operated by a camshaft assembly. Optionally, the camshaft assembly comprises a rotary motor and a lever for generating linear motion of the vaporizing array. In some embodiments, the device and camshaft assembly are configured in a hand held device. Optionally, the hand held device further comprises a control unit. In some embodiments, the control unit is configured for controlling at least one of: a treatment temperature profile of the vaporizing elements, a self-sterilization temperature profile of the vaporizing elements, a penetration distance into the tissue, a dwelling time of the vaporizing elements within the tissue, a velocity of advancing and/or retracting said array, a number of repetitive treatments, a time interval between repetitive treatments, a replacing of the vaporizing elements. In some embodiments, the device is movable in a horizontal direction across the tissue. In some embodiments, the device comprises at least one of wheels and a spring for advancing the array horizontally. Optionally, a penetration depth of the vaporizing elements is reduced by moving the array in parallel to the tissue. In some embodiments, the horizontal movement is operated by a controller.

According to an aspect of some embodiments of the invention there is provided a method for repetitive vaporization of tissue, comprising heating an array of vaporizing elements to vaporize an area in the tissue, elevating the array from the tissue to allow most of the vapours formed during vaporization to escape, and re-applying the array of vaporizing elements to further vaporize the area in tissue.

Optionally, re-applying is performed before the tissue moves. Optionally, re-applying is performed in a time interval shorter than <NUM> msec from a time point in which said vaporizing elements disengaged the tissue. In some embodiments, the method is repeated to vaporize a deeper layer within the tissue. In some embodiments, the method further comprises applying a vaporizable substance to the tissue prior to vaporizing the tissue. Optionally, the vaporizable substance is liquid or gel.

According to an aspect of some embodiments of the invention there is provided a device for heating tissue, comprising a plurality of thermally conductive elements arranged in an array and configured for contacting the tissue; a heating element configured to heat the vaporizing elements; an RF generator; at least one RF conduit for transmitting RF energy to the tissue. Optionally, the array further comprises electrodes adapted for transmitting RF energy into the tissue. In some embodiments, the device is a hand held device.

According to an aspect of some embodiments of the invention there is provided a device for vaporizing a thin layer of tissue, comprising a vaporizing element shaped as a foil; one or more heating elements configured to heat the vaporizing element; a frame holding the vaporizing element, the frame adapted for moving towards and away from the tissue. In some embodiments, the foil vaporizes a tissue layer having a depth smaller than <NUM>. Optionally, the foil is attached to a spring for advancing and retracting the foil from the tissue. In some embodiments, the device further comprises wheels for rolling the device over a surface of the tissue. In some embodiments, the foil is planar and has a surface area ranging between <NUM>^<NUM>- <NUM>^<NUM>. In some embodiments, the foil has a width smaller than <NUM> for vaporizing an elongated narrow crater in the tissue.

According to an aspect of some embodiments of the invention there is provided a device for vaporizing at least one hole in tissue, comprising one or more vaporizing elements arranged in an array; one or more heating elements configured to heat the vaporizing elements; at least one piezoelectric transducer mechanically coupled to the array to move the vaporizing elements towards at least one of the tissue and the one or more heating elements. In some embodiments, the piezoelectric transducer is coupled to the array by a thermally insulating rod. In some embodiments, the transducers are activated by a controller according to an indication of a distance of the array from the tissue to be treated.

According to an aspect of some embodiments of the invention there is provided a pyramidal shaped element for vaporizing a hole in tissue, comprising a thermally conductive core embedded within a biocompatible material, wherein the length of the element ranges between <NUM>-<NUM>. Optionally, the core is formed of copper and the biocompatible material is formed of at least one of titanium and stainless steel.

Optionally, the element is pyramidal shaped. In some embodiments, a length of the core with respect to a total length of the vaporizing element is selected such as to reduce a thermal relaxation time of the element. In some embodiments, the biocompatible material is formed as a sheet having a thickness smaller than <NUM>. Optionally, the sheet is formed with varying thickness.

As referred to herein, the term "vaporizing" may include producing a hole in tissue by delivering heat to the tissue, which causes one or more effects such as turning the tissue of the hole into vapours, ablating tissue, causing denaturation of the tissue, causing crumbling of the tissue into smaller particles, burning the tissue, engraving the tissue, and/or other effects caused by delivering heat to the tissue.

The patent or application file contains at least one drawing executed in colour.

The present invention, in some embodiments thereof, relates to surgical methods and devices, and, more particularly, but not exclusively, to methods and devices for vaporization of tissue.

Some embodiments of the invention relate to a vaporizing element, such as a vaporizing rod, adapted to supply a large amount of heat in a short amount of time to vaporize the tissue, while reducing other types of heat damage such as charring of the tissue. In some embodiments, holes, grooves, craters or indentations are produced in the tissue.

An aspect of some embodiments of the invention relates to an array of vaporizing elements for delivery of heat at a high temperature to a localized area in the tissue, where at least a portion of the vaporizing elements are shaped to prevent excessive penetration of other vaporizing elements into the tissue. In some embodiments, a vaporizing element configured for preventing excessive penetration of a second vaporizing element comprises a leading surface area that is larger than a surface of the second vaporizing element. In some embodiments, an arrangement of the vaporizing elements provides inherent safety during operation, for example by comprising a combination of sharp conical vaporizing rods positioned adjacent truncated vaporizing rods, which limit a movement of the sharp rods deeper into the tissue. In some embodiments, the arrangement of vaporizing elements having different geometries produces a combination of craters of various dimensions, such as various depths, in the tissue. In some embodiments, the vaporizing elements are shaped as pyramids. Optionally, at least a portion of the vaporizing elements comprise a truncated distal end. The cross section area of the truncated elements may affect the dimensions of the crater, for example formed by the non-truncated vaporizing elements.

An aspect of some embodiments relates to an array of vaporizing elements comprising a multilayer structure which contributes to a performance of the array under high temperatures. In some embodiments, the vaporizing element comprises at least one material selected to generate limited vaporization and to reduce a damage region, when the element is heated to an operating temperature, for example a temperate higher than <NUM>. In some embodiments, the material has a thermal conduction coefficient that is greater than <NUM> Watts per degree Kelvin per meter. In some embodiments, the material reduces diffusion in second material, for example a layer of silver reduces diffusion from an underneath layer of copper. In some embodiments, the material is selected to reduce IR emissivity towards the tissue, for example using gold, which has relatively low IR emissivity, to coat the vaporizing element.

In some embodiments, a middle and/or external layer of a vaporizing element is adapted for maintaining a condition of an internal layer. In some embodiments, an internal layer of the vaporizing element is formed of a heat conductive material such as copper, and the copper is optionally coated by a layer configured for reducing diffusion of the copper ions, often occurring at high temperatures, particularly above <NUM>, which is a possible range of temperatures the array is operated at. Optionally, the layer is made of silver. In some embodiments, the silver coated vaporizing elements and/or a surface of a plate onto which the vaporizing elements are mounted is coated with a biocompatible layer, for example a layer of gold and/or rhodium.

Optionally, due to the relatively low IR emissivity properties of gold, the gold layer reduces IR radiation towards a surface of the tissue.

In some embodiments, the heat conductive material such as copper or Aluminium Nitride (ALN) are coated by ceramics or glass, for example providing mechanical protection of the vaporizing elements. The ceramic or glass coating is adapted to withstand high operating temperatures, for example above <NUM>.

In some embodiments, as the multilayer structure withstands high temperatures, the array is adapted for self cleaning and/or self sterilizing. In some embodiments, self sterilization is achieved by heating the vaporizing elements to a temperature over <NUM>. Optionally, tissue particles and/or carbonized particles that adhered to the vaporizing elements are removed by the self sterilization process, for example as a result of oxidation transforming carbon residue into CO2.

An aspect of some embodiments relates to a cyclic movement profile of an array of vaporizing elements. In some embodiments, the movement profile includes accelerating the array of vaporizing elements to a rate high enough for shortening a dwelling duration of the vaporizing elements within the tissue. In some embodiments, the movement profile includes elevating the tips of the vaporizing elements from the tissue between repetitive treatments, for releasing vapours that are trapped between the tissue and tips of the vaporizing elements. In some embodiments, the cyclic movement profile includes setting a time interval between repetitive treatments that is short enough to prevent tissue movement in between treatments. Optionally, by repetitive and vaporization of an area in the tissue, a deeper crater can be produced. In some embodiments, a camshaft mechanism is utilized for operating the array in a cyclic movement profile. Optionally, the camshaft assembly includes a rotary motor, a wheel, and a lever for generating linear motion of the vaporizing array.

In some embodiments, the vaporizing elements of the array are moved together. Alternatively, one or more vaporizing elements are moved independently of other elements.

In some embodiments, the array is movable in a horizontal direction.

Optionally, moving the array vertically and horizontally, a penetration depth of the array may be reduced. In some embodiments, the horizontal movement provides for increasing a width of a crater formed in the tissue.

An aspect of some embodiments relates to a vaporizing array connected to an RF generator. Optionally, the vaporizing elements of the array are adapted for transmitting RF energy to the tissue. Additionally or alternatively, different RF electrodes are used, for example being mounted to the same plate that the vaporizing elements are mounted on.

In some embodiments, a vaporizing element is shaped as a thin foil, adapted to vaporize a thin layer of tissue, for example a crater having a maximal depth of <NUM> with respect to the uppermost surface of tissue.

In some embodiments, a lesion pattern of elongated, narrow craters is produced in the tissue. Optionally, the pattern of elongated, narrow craters is obtained by using one or more vaporizing elements shaped as a wire. In some embodiments, a plurality of wires are assembled on a device configured for rolling on a surface of the tissue, for forming a lesion pattern of elongated, narrow craters.

In some embodiments, the vaporizing array and/or a single vaporizing element is incorporated in a hand held device. Optionally, the hand held device comprises a control unit, for controlling parameters related to vaporizing tissue and/or to limiting damage to the tissue, such as the treatment temperature profile, a penetration depth of the vaporizing elements in the tissue, a motion profile of the vaporizing elements, a dwelling duration of the element in the tissue, a time interval between repetitive treatment pulses.

An aspect of some embodiments relates to a vaporizing array assembly comprising one or more piezoelectric transducers. In some embodiments, the transducers are mechanically coupled to the array and configured to move the array towards the tissue and/or towards the heating element, be deforming in response to electrical activation. Optionally, the transducers are activated by a controller, for example according to an indication of a distance of the array from the tissue to be treated.

Referring now to the drawings, <FIG> are a side view and a front view, respectively, of an array of vaporizing elements, according to some embodiments of the invention.

In some embodiments, array <NUM> comprises at least one vaporizing element, such as conical rod <NUM> and/or conical rod <NUM>. In some embodiments, a vaporizing element is adapted to supply a large amount of heat, in a short amount of time, to vaporize at least a portion of tissue <NUM>. In some embodiments, holes, grooves, indentations and/or craters are produced in tissue <NUM>.

In order to vaporize tissue while not destroying tissue which should not be vaporized, the present invention, in some embodiments thereof, teaches applying heat at a high temperature to a localized area in tissue. In some embodiments, the temperature should be high enough to rapidly vaporize the tissue, that is, a temperature above <NUM> degrees Celsius, which is a boiling temperature of water, which is a major constituent of tissue. Preferably, the temperature should be higher than approximately <NUM> degrees Celsius, for example ranging between <NUM>-<NUM> degrees Celsius, for example <NUM>, <NUM>, <NUM>, or <NUM> degrees Celsius.

In some embodiments, due to the high temperature profile, bleeding of the vaporized tissue is reduced. In some embodiments, due the high temperature profile, craters are formed with defined borders, and collateral damage is reduced. For example, damage surrounding the formed crater can be limited to an extent less than <NUM>, less than <NUM>, less than <NUM>µ or intermediate, larger or smaller extents from the periphery of the crater.

In some embodiments, the heat capacity of the vaporizing element should be such that a tip such as tip <NUM> of the vaporizing element which is adjacent to the tissue contains an amount of heat which is enough to vaporize tissue <NUM> which is adjacent to the tip. The amount of heat necessary to vaporize tissue is dependent on the volume to be vaporized. The volume to be vaporized approximately equals a cross section of the tip, multiplied by the depth which is to be vaporized. In the case of a sharp pyramidal tip, the vaporized volume is one third of that multiplication, resulting in the capability to vaporize deeper craters with same width and same energy.

In some embodiments, the vaporizing elements such as elements <NUM>, <NUM> are bonded to a plate <NUM>, for example soldered and/or adhesively bonded and/or mechanically bonded for example using pins or screws to plate <NUM>.

In some embodiments, plate <NUM> is coupled to a heating element <NUM>. In some embodiments, the heating element is a high temperature foil, an electrically heated wire, an optical heat source, a metallic heating element, and/or any other heating element suitable for heating the vaporizing elements to a temperature ranging between <NUM>-<NUM> degrees Celsius. In some embodiments, heating element <NUM>, for example being a foil, is heated by an electrical resistor <NUM>.

In some embodiments, the vaporizing device comprises a single vaporizing element. Alternatively, the vaporizing device comprises an array of vaporizing elements, for example between <NUM>-<NUM> vaporizing elements, such as <NUM> elements, <NUM> elements, <NUM> elements, or any intermediate, higher or smaller number of elements.

Various vaporizing elements may comprise different shapes, for example a vaporizing element may have a conical profile, a circular profile, a rectangular profile, a pyramidal profile, a trapezoidal profile, or any other shape. This figure, for example, shows vaporizing elements such as <NUM> and <NUM> having a conical profile. Optionally, a single array comprises elements of various shapes.

In some embodiments, at least a portion of the vaporizing elements are configured for preventing excessive penetration of other vaporizing elements, for example by the vaporizing element having a leading surface area adapted for contact with tissue that is larger than a leading surface area of a different vaporizing element which is prevented from further penetrating the tissue. For example, a leading surface of vaporizing element <NUM> (pointed to by <NUM> in <FIG>) is larger than a leading surface area of vaporizing element <NUM> (pointed to by <NUM> in <FIG>), for example <NUM>%, <NUM>%, <NUM>% <NUM>% or intermediate, larger or smaller percentages larger. Optionally, the size of the leading surface area of, for example, element <NUM> is determined according to the desired penetration depth of, for example, element <NUM>. Optionally, the larger the leading surface is, the more resistance applied by the surface of the tissue, preventing additional penetration of at least some of the elements.

In some embodiments, a vaporizing element such as element <NUM> comprises a sharp tip <NUM> adapted for penetrating into the tissue. Alternatively, a vaporizing element such as element <NUM> comprises a blunt, truncated tip, such as tip <NUM>. In some embodiments, truncated element <NUM> is configured for abutting against a surface of the tissue. Additionally or alternatively, truncated element <NUM> is configured for pushing against a surface of the tissue. Additionally or alternatively, truncated element is configured for forming a crater that is shallower than, for example, a crater formed by element <NUM>.

In some embodiments, array <NUM> comprises a combination of sharp and truncated elements. Optionally, vaporizing elements such as truncated element <NUM> prevent excessive penetration of elements such as sharp element <NUM> to a deep tissue layer. Optionally, the combination of sharp and truncated elements limits a movement of the array as it is introduced onto the tissue, for example onto skin, thereby providing an inherent safety mechanism. In some embodiments, dimensions of a crater formed in the tissue can be predicted, for example a maximal depth can be determined according to a difference between the length of, for example, sharp vaporizing element <NUM> (having a length L2) and truncated vaporizing element <NUM> (having a length L1).

In some embodiments, array <NUM> comprises a combination of vaporizing elements having various lengths. Optionally, craters with different depths are formed when elements of different lengths are used. For example, as shown in this figure, element <NUM> having a length L1 is shorter than element <NUM> having a length L2. In some embodiments, a length of a vaporizing element ranges between <NUM>-<NUM>.

In some embodiments, vaporizing elements advance between <NUM> to <NUM> into the tissue, in the vaporizing phase.

In some embodiments, array <NUM> comprises a combination of vaporizing elements having various geometrical profiles and/or cross section areas. Optionally, craters are formed with different cross section areas and/or different volumes and/or different geometrical profiles, optionally complying with the dimensions of the vaporizing elements.

In some embodiments, an arrangement of array <NUM> is determined such as to produce a certain lesion pattern, for example to form craters having a predetermined distance between them. For example, as shown in <FIG>, distances such as L3 between tips of the vaporizing elements are determined to form craters having a similar distance L3 between their centers. In some embodiments, a distance L3 between adjacent tips (and/or distal end surfaces, and/or a tip and a distal end surface) of the vaporizing elements ranges between <NUM> -<NUM>.

In some embodiments, an arrangement of the array is provided such as to form a certain spatial distribution of craters in the tissue. In an example, the vaporizing array arrangement can be provided such as to form craters at a spatial distribution of <NUM>-<NUM> craters/cm^<NUM>. In some embodiments, an arrangement of the vaporizing elements of array <NUM> is provided to form deep craters surrounded by shallow indentations, and/or any other lesion patterns.

In some embodiments, a crater depth, as measured from an external surface of the tissue, ranges, for example, between <NUM>-<NUM>. In some embodiments, a crater depth is identical to the penetration depth of the vaporizing element. It should be noted that in some cases, the crater depth is not necessarily identical to the penetration depth of the vaporizing element, as heat is diffused from the element into the tissue and may vaporize tissue ahead of the vaporizing element.

In some embodiments, the vaporizing elements are heated by heating element <NUM> through plate <NUM>. In some embodiments, a coupling between plate <NUM> and heating element <NUM> allows fast transfer of heat from heating element <NUM> to plate <NUM>.

Optionally, surfaces of the plate <NUM> and/or heating element <NUM> directed towards each other are flat so that a minimal gap is formed between them, increasing the rate of heat transfer. For example, a surface of the plate and/or a surface of the heating element are made with a height tolerance smaller than <NUM>, as calculated over, for example, a <NUM>^<NUM> area, to enlarge an area of contact between the surfaces.

Optionally, the heat transfer rate is sufficient to provide a rate of <NUM> treatment per second (i.e. a single application of the array to the treated tissue). For example, the heat transfer rate between heating element <NUM> and plate <NUM> is at least <NUM> Joule per second. In some embodiments, one or more heating elements <NUM> are operable at a protocol suitable for vaporizing tissue by the vaporizing elements. Optionally, the heat transfer rate from the one or more heating elements is high enough to provide for the vaporizing elements to effectively heat the tissue at a relatively short amount of time. In some embodiments, the plate and vaporizing elements assembly and/or only a portion of it, such as the tips of the vaporizing elements, is heated to approximately <NUM> degrees Celsius within less than <NUM> sec.

By way of a non-limiting example, in order to vaporize an area of <NUM> microns by <NUM> microns, to a depth of <NUM> microns, approximately <NUM> milliJoules of heat are needed, based on the vaporization energy of water which is approximately <NUM>,<NUM> Joule/cm3. It is noted that the heat needed to vaporize tissue is substantially close to the heat needed to vaporize water, since tissue thermal parameters are very similar to water thermal parameters.

In order to supply the heat to the tissue, the heat relaxation time of the vaporizing element, should be such that the heat can come rapidly to the surface of the tip of the vaporizing element. It is noted that the heat relaxation time depends, among other factors, on heat conductivity, heat capacity, and geometric dimensions, such as length, of the vaporizing element.

The heat supply should be fast enough to vaporize the adjacent tissue without allowing too much heat to diffuse into the tissue, that is, a heat relaxation time substantially shorter than that which produces an allowed or planned necrosis depth in tissue. By way of approximation, the heat relaxation time should be substantially shorter than that of water.

In some embodiments, the vaporizing element (or, alternatively, an array of vaporizing elements) is "flicked" onto the tissue for a very short and limited amount of time. The flicking keeps the vaporizing element adjacent, optionally in contact, to the tissue for only a short time, limiting time for heat conductance into tissue, and limiting collateral damage to acceptable levels.

In some embodiments, the vaporizing element is considered as providing heat to the tissue as long as the vaporizing element is adjacent to the tissue. In some embodiments, the vaporizing element is considered as providing heat to the tissue as long as the vaporizing element is within the volume of the crater.

In order to provide heat rapidly to the tissue, a vaporizing element comprises at least one material allowing fast thermal conduction. In some embodiments, the vaporizing element includes material having a thermal conduction coefficient greater than <NUM> Watts per degree Kelvin per meter. In some embodiments, the vaporizing element includes material having a specific heat capacity greater than <NUM> kiloJoules per kilogram per degree Kelvin. In some embodiments, the vaporizing element includes a material with heat conductivity equal to or higher than heat conductivity of copper. In some embodiments, the vaporizing element includes a material with specific heat capacity equal to or higher than specific heat capacity of copper. Some materials, such as some metals, have thermal conductivity as high as, by way of a non-limiting example, copper, enable such rapid heat flow. In some embodiments, the vaporizing element includes a material with a heat conduction coefficient equal to or greater than the heat conduction coefficient of stainless steel.

In some embodiments, for example when creation of extremely shallow craters is advantageous, the vaporizing elements may comprise a material having heat conductivity equal to or lower than the heat conductivity of glass.

In some embodiments, vaporizing elements of different materials are combined together, for example in a single array. For example, a portion of the vaporizing elements of an array are made of copper, and a second portion of the vaporizing elements of an array are made of stainless steel. Optionally, due to different heat conduction properties of the materials, craters of various depths can be formed in the tissue. For example, elements made of stainless steel, having a thermal conductivity about <NUM>/30th of that of copper, may form shallower craters than those formed by the copper elements. A potential advantage includes modifying the treatment 'aggressiveness' by combining vaporizing elements of different materials, for example in a single array.

In some embodiments, when applying a vaporizing element to the tissue, the tissue is stretched. Optionally, stretching ensures homogenous contact with the tissue, as further disclosed by <CIT>.

In some embodiments, the vaporizing elements are applied to the tissue for treating various conditions, for example aesthetic applications such as treating wrinkles and/or scars on the skin, performing skin resurfacing or skin rejuvenation, treating nail tissue, and/or treating other tissue such as treatment of oral, nasal or ear cavities, treatment of the ear drum, treatment of vocal cords, treatment of respiratory system tissue, esophagus tissue, vaginal tissue, abdominal tissue.

<FIG> show various array configurations, according to some embodiments of the invention.

<FIG> is a side view and <FIG> is a front view of an array comprising vaporizing elements shaped as cylindrical rods, such as rods <NUM> and <NUM>. In some embodiments, at least a portion of the rods are shorter than others, for example rod <NUM> is shorter than rod <NUM>. In some embodiments, the rods form craters having various depths, such as crater <NUM> and deeper crater <NUM>.

In some embodiments, dimensions of the rods are determined according to the type of treatment. For some implementations, such as skin resurfacing, an array such as the array shown in <FIG> comprising <NUM> X <NUM> rods, for example having a diameter D of <NUM> - <NUM>, and a distance S of <NUM> - <NUM> in between the rods may be used. Optionally, in this case, the rod length L may range between <NUM> - <NUM>, for example <NUM> for the short rods such as <NUM>, and <NUM> for the long rods such as <NUM>. In another example, the difference between a long rod and a short rod may range between, for example, <NUM>-<NUM>, such as <NUM>, <NUM>.

<FIG> is a side view and <FIG> is a front view of an array comprising vaporizing elements shaped as pyramids <NUM>. In some embodiments, for example as shown in this figure, the vaporizing pyramids are equally sized. Alternatively, the vaporizing elements may comprise different sizes, for example different lengths.

In some embodiments, dimensions of a vaporizing element are defined to prevent possible bending of the element, which may occur as a result of heating the vaporizing element to a high temperature. A vaporizing element may gradually bend, for example as a result of softening of the metal comprising the vaporizing element, such as softening of copper. Optionally, bending occurs as a result of multiple treatments, where the vaporizing element is heated, cooled, and heated again.

Optionally, bending is affected by an angle formed between a vaporizing element (or an array of elements) and the tissue. It is possible that by positioning the vaporizing element perpendicularly to the tissue, such that an angle of approximately <NUM>° is formed between the tissue and the vaporizing element, bending of the vaporizing element is reduced. Optionally, bending over time causes displacement of the distal ends of the vaporizing elements, and may result in misplaced crater formation. For example, when repetitive treatment is applied, the vaporizing elements may not contact the same tissue area that they previously contacted, and an area of healthy tissue between the craters may be damaged.

In some embodiments, a ratio between a length of the vaporizing element and a width of its base has been found to affect the bending. The inventors have concluded that the ratio between the length of the vaporizing element and a width of the base for example in the case of copper elements that are heated to an operating temperature of <NUM>, should range between <NUM>:<NUM> to <NUM>:<NUM>. A potential advantage of the pyramidal shape element, in view of the bending phenomena, is the ability to use a relatively sharp tip, for example having a width of <NUM>-<NUM> at a distal surface, with a relatively long body, for example having a height of <NUM>.

In experiments conducted by the inventors, <NUM> long rods having a <NUM> base width (i.e. having a ratio of <NUM>:<NUM>) were heated to <NUM> degrees Celsius to treat a 1X1 cm^<NUM> area of tissue, <NUM> times. At the end of operation, some bending was observed on the rods.

On the other hand, rods having a length of <NUM> and a base width of <NUM> did not show bending at all.

In another example, a copper pyramidal element having <NUM> base width, a length (height) of <NUM>, and a width of <NUM> micron at a surface of the distal tip, did not show bending as well.

<FIG> is a block diagram of a system for vaporizing tissue using a vaporizing element or an array of vaporizing elements, according to some embodiments of the invention. In some embodiments, an array of vaporizing elements <NUM> is coupled to a heating element <NUM>. Optionally, heating element <NUM> has a planar configuration, for example being a foil. Optionally, heating element <NUM> has a cylindrical configuration, and/or any other shape. Heating element <NUM> is optionally heated by an electrical resistor <NUM> and/or by any other means, such as an optically heated source, an ultrasound source, or an exothermic chemical reaction.

In some embodiments, electrical resistor <NUM> is connected by an electrical circuit to a power source <NUM>, for example a battery or a power connection such as a <NUM>/<NUM> supply line. Optionally, the heating element can be separated from the power supply, for example a decoupling mechanism may be utilized between multiple treatments to disconnect heating element <NUM> from power source <NUM>. In some embodiments the vaporizing elements are electrically insulated from the electric power supply, also so as not to produce an electrical contact with the tissue being vaporized.

In some embodiments, the vaporizing array <NUM> is heated by a wireless heating method, such as optical heating by light waves, or heating by microwaves.

In some embodiments, heating element <NUM> comprises a temperature sensor <NUM>, such as a thermistor or a thermocouple, for monitoring a temperature of the heating element and/or a temperature of the vaporizing element.

In some embodiments, array <NUM> is coupled optionally through plate <NUM> to a heat sink <NUM>. Optionally, the heat sink is coupled to a frame or housing of the array (not shown in this figure), for example to prevent a user from holding a heated component. In some embodiments, the heat sink comprises a water tank. In some embodiments, the heat sink comprises a thermoelectric chiller. A thermostat may be connected to the heat sink to control a temperature.

In some embodiments, array <NUM> and/or power source <NUM> are connected to a control unit <NUM>. Control unit <NUM> is connected, in some embodiments, to a second power source <NUM>. Optionally, a single power source is used for supplying power to heating element <NUM> and to control unit <NUM>.

The following are some non-limiting examples of parameters which can be automatically and/or manually controlled through control unit <NUM>. Some parameters may be selected by a user, while others may be automatically controlled by control unit <NUM>. Some parameters may be set as a combination of both automatic and manual control. In some embodiments, control unit comprises a user interface. Some exemplary parameters are listed below:.

In some embodiments, a system for example as described herein is configured as a hand-held device. Optionally, to provide a comfortable and safe use of the device, a temperature of the device housing is controlled, for example by positioning a temperature sensor adjacent to the external housing, to prevent it from overheating.

Optionally, a temperature sensor is positioned on and/or adjacent array <NUM> to detect a temperature of the array. Optionally, the array temperature is monitored, for example to prevent overheating of the vaporizing elements.

In some embodiments, at least a portion of array <NUM> is detachable, and can optionally be disposed, for example after a certain number of treatments such as <NUM>, <NUM>, <NUM>, <NUM> or any other number of treatments. Optionally, array <NUM> is disposed of and replaced, for example in between patients.

<FIG> are schematic cross sections of a vaporizing element (4A) and a plate onto which the elements are mounted (4B), according to some embodiments of the invention.

In some embodiments, a vaporizing element (for example as shown in <FIG>) and/or a plate (for example as shown in <FIG>) onto which one or more vaporizing elements are mounted or are integrally connected to, comprise a multilayer structure, for example comprising <NUM>, <NUM>, <NUM>, <NUM>, or any other number of layers. Optionally, each layer comprises a different material. Optionally, each layer comprises a different thickness. In some embodiments, a material of the multilayer structure is selected to generate limited vaporization, for example as compared to an element formed only of copper. In some embodiments, a material is selected to reduce a damage region, for example surrounding the location of treated tissue. It is necessary that at least some of the materials from which the vaporizing element is constructed have a high thermal conductivity, for example having a thermal conduction coefficient higher than <NUM> Watts per degree Kelvin per meter. In some embodiments, a layer is adapted for maintaining a condition of an internal layer, for example a layer may reduce diffusion of particles from a layer underneath it. In some embodiments, at least one layer such as the external layer of the vaporizing element and/or the external layer of the plate that optionally have direct contact with tissue comprise a biocompatible material. In some embodiments, at least one layer such as the external layer has a relatively low IR emissivity level, and is capable of reducing IR radiation towards the tissue. In some embodiments, a layer such as an external comprises an electrically insulating material, such as Sapphire, so as not to produce an electrical contact with the tissue being vaporized. For example, a thin (such as <NUM> micron) layer of sapphire may efficiently conduct heat to tissue, while providing an electrical insulation.

Reference will be made now to <FIG>, which shows a conical vaporizing element comprising three layers. In some embodiments, a body <NUM> of a vaporizing element is made a material comprising a relatively high thermal conduction coefficient, such as copper. Other materials may include aluminium nitride, stainless steel, ceramics, glass, and/or combinations of them, depending on the type of application.

In some embodiments, body <NUM> is made of sintered copper, and/ or sintered stainless steel, and/ or sintered aluminium nitride (ALN). Optionally, a sintered material comprises less burrs, for example as opposed to machined material.

Optionally, a surface of the sintered material is smooth enough so that it can be uniformly coated, for example by a different material.

In some embodiments, body <NUM> is coated by second layer <NUM>, for example made of silver. Optionally, a thickness of layer <NUM> ranges between <NUM>-<NUM>. The inventors have shown that silver layer <NUM> is capable of reducing diffusion of copper ions <NUM> in body <NUM>, a commonly known phenomena which may be observed in copper heated to high temperatures, for example heated to <NUM> degrees Celsius. A potential advantage of reducing and/or eliminating the diffusion of copper includes maintaining biocompatibility of the heated material. In some embodiments, layer <NUM> is coated by an additional layer <NUM>. In some embodiments, layer <NUM> comprises a biocompatible material, as it comes in direct contact with tissue. In some embodiments, layer <NUM> comprises a material having relatively low IR emissivity, and may reduce IR radiation towards the treated tissue. In some embodiments, layer <NUM> is made of gold and/or rhodium. Additionally or alternatively, layer <NUM> comprises carbon, diamond, graphene, palladium, titanium nitride, titanium, stainless steel and/or other materials. Optionally, a thickness of layer <NUM> ranges between <NUM>-<NUM>.

Optionally, layer <NUM> acts as a barrier to diffused silver ions, preventing the released ions from reaching the tissue.

In some embodiments, layer <NUM> and/or layer <NUM> comprise a material that is optionally less heat conductive than a material from which body <NUM> is made of, for example layer <NUM> and/or layer <NUM> can be made of stainless steel or titanium.

In some embodiments, a thickness ratio between the layers changes along various portions of the vaporizing element, for example tip <NUM> at a distal end of the vaporizing element may be structured such that body <NUM> extends to the end of the tip, and a thickness of layers <NUM> and/or <NUM> is reduced. In some embodiments, layers such as coating layers <NUM> and/or <NUM> are not evenly distributed, and are thicker along some portions and thinner in others.

In some embodiments, the layered structure is manufactured using electroplating technologies. In some embodiments, the layers are deposited using chemical vapor deposition techniques, and/or by sputtering. For example, a layer of titanium nitride can be applied by sputtering.

<FIG> shows an exemplary layer structure of a plate, according to some embodiments of the invention. In some embodiments, a layer structure of the plate is similar to the layer structure of a vaporizing element. Alternatively, the plate comprises a different layer structure than the vaporizing element. In some embodiments, the plate comprises a single layer, for example made of copper, ceramics and/or stainless steel.

In some embodiments, a total thickness of the plate is thick enough to prevent bending of the array, and on the other hand, thin enough to allow a rapid transfer of heat from the heating element to the vaporizing elements. Optionally, a total thickness of the plate ranges between <NUM> - <NUM>, for example <NUM>, <NUM>, <NUM>.

As shown in this example, the plate comprises three layers, similarly to the vaporizing element in <FIG>: A copper layer <NUM>, optionally facing a surface of a heating element, a middle layer <NUM>, for example made of silver, and an external layer <NUM>, for example made of gold and/or rhodium, facing towards the tissue.

In some embodiments, only some portions of the plate, for example exposed surfaces in between vaporizing elements, are coated by a biocompatible material and/or an IR radiation reducing material such as gold.

In some embodiments, the vaporizing elements and/or plate are manufactured using a metal injection moulding process, in which powdered metal is mixed with binder material to form a 'feedstock' mix, which is then injected to a hollow mould, and sintered to produce the final product. Optionally, conditions such as a sintering temperature, the type of materials used, the mould dimensions are selected such that the end product is accurately formed according to preselected dimensions.

<FIG> is a flowchart of a method for self-sterilization of an array comprising vaporizing elements, according to some embodiments of the invention.

In some embodiments, as the multilayer structure withstands high temperatures, the array is adapted for self-cleaning and/or self-sterilizing. In some embodiments, self-cleaning maintains a char free array. In some embodiments, self-sterilization is required to clear an array from tissue particles and/or carbonized particles that may have adhered to the array during treatment.

In some embodiments, the method includes applying vaporization treatment to the tissue (<NUM>), for example skin tissue. Optionally, repetitive treatment is applied, for example comprising <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or any intermediate or higher repetitions. Following treatment, for example once a desired vaporization depth was achieved, the array is moved away from the treated tissue (<NUM>).

In some embodiments, to clean and/or sterilize the array, the array is heated to a temperature over approximately <NUM> degrees Celsius (<NUM>). In one example, the array is heated to <NUM> degrees Celsius for time period ranging between <NUM>-<NUM> seconds. Optionally, heating to such a high temperature causes oxidation, which transforms carbon residue such as tissue particles and/or carbonized particles that exist on the array into CO2 vapours.

The inventors have conducted experiments to prove the cleaning effectiveness of heating to a temperature over <NUM> degrees. They applied treatment to tissue at <NUM>-<NUM> degrees Celsius, which gradually caused a thin carbonization layer to form on a surface of some vaporizing elements and on a portion of the plate. After removal of the array from the tissue, the array was heated to <NUM> degrees Celsius for a time period ranging between <NUM>-<NUM> seconds, after which all carbonization residues were discarded.

In some embodiments, sterilization and/or cleaning is applied after a certain number of treating pulses, for example <NUM>-<NUM> treating pulses. In some embodiments, sterilization is applied according to accumulating operation time, for example every <NUM> seconds, <NUM> seconds, <NUM> minutes, <NUM> minutes, <NUM> minutes, <NUM> minutes, or intermediate, higher or smaller durations of operation.

In some embodiments, one or more vaporizing elements and/or the array of vaporizing elements are removed from the device (e.g. a handheld device), for example following treatment, and are replaced by new vaporizing elements or a new array of vaporizing elements. Optionally, replacing is performed robotically.

Optionally, replacing is controlled by a controller of the device.

<FIG> is a flowchart of a method for applying repetitive treatment pulses, according to some embodiments of the invention.

In some embodiments, vaporizing the tissue includes applying repetitive treatment pulses, for example for producing a deeper crater in the tissue.

In some embodiments, a first treatment pulse is applied (<NUM>). In some embodiments, following the treatment pulse, the vaporizing elements are elevated from the tissue (<NUM>), for example elevated so that their distal tips are positioned above a surface of the tissue. Optionally, vapours such as CO2 vapours may be trapped between a distal end of a vaporizing element and the crater, and by elevating the vaporizing element at least a portion of the vapours, such as <NUM>%, <NUM>%, <NUM>% of the formed vapours are allowed to escape. A potential advantage of releasing vapours may include vaporizing deeper craters.

In some embodiments, a ventilator is coupled to the device to accelerate the clearing of the vapours. Additionally or alternatively, a pump or other device capable of providing suction is coupled to the device to accelerate the clearing of vapours.

In some embodiments, a second treatment pulse is applied (<NUM>). Optionally, the second treatment is applied within a time interval short enough so that tissue movement is prevented. Optionally, this allows for repositioning a vaporizing element in a similar location with respect to the crater walls as it was positioned before, optionally reducing collateral damage and/or the formation of craters with poorly defined borders.

In some embodiments, repetitive treatment pulses are applied (<NUM>), such as <NUM> pulses, <NUM>, pulses, <NUM> pulses, <NUM> pulses. In one example, <NUM> treatment pulses are applied with a <NUM> msec time interval between them. In some embodiments, <NUM>-<NUM> treatment pulses are applied within a <NUM> second time period. Optionally, a time interval between two treatment pulses is shorter than <NUM> msec.

Optionally, by applying repetitive treatment pulses, deeper tissue layers are vaporized, forming deeper craters.

Repetitive treatment for formation of deeper craters may be useful, for example, in cases where a thick epidermis layer exists, and attaining a papillary dermis layer is desired.

<FIG> are histological results of tissue vaporization, according to some embodiments of the invention.

The histological results shown in both examples were obtained by using an array of 9X9 pyramidal shaped vaporizing elements, each pyramid having a height of <NUM>, and a width of an edge of the square base of <NUM>. Each element comprised a copper body coated by a layer of nickel and/or gold, having a thickness of <NUM>.

In <FIG>, a single treatment pulse was applied at <NUM> degrees Celsius to the tissue. The image shows a single crater <NUM>, formed by a single vaporizing element. Applying a single treatment pulse resulted in forming the relatively superficial crater in the papillary dermis, which was <NUM>.

In <FIG>, a triple treatment pulse was applied at <NUM> degrees Celsius to the tissue. A time interval between the repetitive treatment pulses was <NUM> msec. As can be observed, a deeper (having a depth of approximately <NUM> micron) damaged zone <NUM> was formed in the tissue, having clearly defined walls.

<FIG> shows a cyclic movement profile implementation, for example utilizing a camshaft mechanism, according to some embodiments of the invention.

In some embodiments, operating of an array of vaporizing elements includes producing a cyclic movement profile of the array. In some embodiments, the absolute acceleration rate of the vaporizing elements increases as the elements advance toward the tissue. Optionally, the maximal absolute acceleration rate is achieved at the tissue contact point. Optionally, once the element contacts the tissue, the direction of velocity reverses, and the element is retracted from the tissue. Optionally, the reversal of direction occurs within a relatively short duration, for example ranging between <NUM> microsec and <NUM> millisec from a time of contact with the tissue. In some embodiments, the absolute acceleration rate increases along at least a portion of the pathway of the elements towards the tissue, for example along <NUM>%, <NUM>%, <NUM>%, <NUM>% or intermediate, larger, or smaller portions of the pathway. Optionally, the absolute acceleration rate increases at the initial advancement of the array towards the tissue.

Additionally or alternatively, the absolute acceleration rate increases as the array moves closer to the tissue.

In some embodiments, the absolute acceleration rate is set such as to achieve a short dwelling time of the vaporizing elements within the tissue, for example 100µsec.

It is possible that by shortening a dwell time in tissue, collateral damage is reduced. It should be noted that in some cases, a longer dwell time such as <NUM> -<NUM> msec is desirable, for example in cases where delayed healing is advantageous. Additional exemplary dwelling times of vaporizing elements are <NUM> msec, <NUM> msec, <NUM> msec, <NUM> msec and <NUM> msec. The selection of dwelling time duration also depends on the vaporizing tip material. For example, a copper tip may require <NUM> msec for vaporization of a <NUM> micron deep crater, an ALN tip may require <NUM> msec and a stainless steel tip may require <NUM> or <NUM> millisecond.

Exemplary absolute acceleration rates range between, for example, <NUM> - 2X10^<NUM>/sec^<NUM>, for example between 2X <NUM>^<NUM> - 2X <NUM>^<NUM>/sec^<NUM>.

In some embodiments, a camshaft based mechanism, for example as shown in <FIG>, is utilized for generating a cyclic movement profile of an array, transforming angular velocity into linear velocity of the array.

In some embodiments, a motor <NUM> operates a rotating wheel <NUM>, for example spinning the wheel at an angular velocity w. In some embodiments, motor <NUM> is a DC motor. Motor <NUM> can be a stepper motor, an axial rotor motor, or any other type of motor suitable for causing a rotation of wheel <NUM>.

In some embodiments, wheel <NUM> is attached to a lever <NUM>, which translates a circular motion of wheel <NUM> to a linear motion of the array of vaporizing elements <NUM>. In some embodiments, a shaft <NUM> connects between lever <NUM> and array <NUM>.

During operation, rotation of wheel <NUM> causes lever <NUM> to lift and lower shaft <NUM> by a distance, which ranges between, for example, <NUM> - <NUM>, for example <NUM>-<NUM>, at a linear velocity V, which changes as a function of the array position.

In some embodiments, for example to provide precise control over the oscillations of the array of vaporizing elements, specifically of the distal tips of the vaporizing elements, marked by distance X, measuring means such as a micrometre can be used. Optionally, the micrometre is attached to wheel <NUM>. In some embodiments, distance X ranges between <NUM>-<NUM>.

In some embodiments, distance X affects the protrusion of the vaporizing elements of array <NUM> from a distal end of a housing of the treatment device <NUM>, for pushing against the tissue during treatment. The extent of the protrusion may range, for example, between <NUM>-<NUM>, such as <NUM>, <NUM>, <NUM>, <NUM>. In some cases, for example when tissue such as skin tissue is pushed up while placing and pressing the array against the skin, at least a portion of the skin may bulge in between the vaporizing elements. In such a case, the extent of protrusion can be referred to as a negative distance, for example -<NUM>, thus compensating for the skin bulging.

In some embodiments, linear velocity V of the array ranges between <NUM>-<NUM>/sec, such as <NUM>-<NUM>/ sec, <NUM>-<NUM>/sec, <NUM>-<NUM>/sec.

In some embodiments, an encoder such as an, optocoupler, Hall magnetic sensor, or any other circuit, is incorporated into motor <NUM>, for generating an indication of a current position of array <NUM>, and/or information about the wheel velocity, and/or information about the array velocity.

In some embodiments, an indication is transferred to a control unit, for example as explained hereinabove. Optionally, the control unit activates the camshaft mechanism, for example according to parameters selected by a user, and/or parameters selected automatically by the control unit. For example, a user can select parameters such as the velocity of array, the advancement and retraction distance, a dwelling time of the array in the tissue, a number of repetitions, a penetration depth of the vaporizing elements in the tissue, and/or any other parameters.

In some embodiments, array <NUM> is attached to a spring. Optionally, a stiffness of the spring and/or an oscillation distance of the spring affect an acceleration rate of the array towards the tissue, and/or a dwelling time of the vaporizing elements within the tissue.

In some embodiments, the array assembly, for example operated by the camshaft mechanism and/or the spring, comprises a sensor adapted for detecting a current position of the array, such as an optocoupler.

In some embodiments, the array assembly comprises a sensor for measuring a dwelling duration of the vaporizing elements within the tissue, for example by measuring electrical conductivity of the tissue using, for example, a resistor and a low voltage power supply such as a battery. Optionally, the power supply is low enough to maintain the current level under a level set by clinical standards, for example <NUM> microampere.

In some embodiments, a safety mechanism is configured for receiving an input from a sensor, for example as described herein, and elevating the array and/or pushing the tissue ahead away from the array if the dwelling duration is longer than permitted and/or if a current position of the array indicates malfunction. Optionally, an additional spring is provided for elevating the device in case of malfunction.

Optionally, a push-down frame is provided for pushing the tissue away from the array in case of malfunction.

<FIG> shows an exemplary graph indicating a cyclic movement profile of a vaporizing array, according to some embodiments of the invention. The graph shows an absolute acceleration rate <NUM> of the vaporizing array as a function of location with respect to the treated tissue <NUM>. In some embodiments, as the vaporizing array advances toward the tissue, the absolute acceleration rate increases, reaching a maximal absolute value upon contact with tissue <NUM>. Optionally, for example upon reaching the desired depth in tissue, the direction of the vaporizing array is reversed and the vaporizing array is elevated from the tissue. Optionally, for example when repetitive pulses are applied, as shown in this figure, the direction of the array is reversed again so that it advances toward the tissue and so forth. In some embodiments, the movement profile of the vaporizing array is determined such as to shorten a dwelling duration of the elements within in the tissue.

<FIG> is a block diagram of a system for tissue vaporization comprising an RF generator, according to some embodiments of the invention.

In some embodiments, an RF generator <NUM> is incorporated in a system, for providing a dual functioning device adapted for a thermal activation mode and an RF energy activation mode.

In some embodiments, array <NUM> comprises a combination of vaporizing elements <NUM>, and RF electrodes <NUM>. Alternatively, vaporizing elements <NUM> are adapted for transmitting RF energy to the tissue. Optionally, vaporizing elements made of metal such as copper and/or stainless steel are suitable for transmitting the RF.

Alternatively, array <NUM> comprises only RF electrodes. In some embodiments, a conduit <NUM> such as an RF antennae is used for transferring RF energy from generator <NUM> towards the tissue. In some embodiments, the array comprises thermally conductive elements, which are not necessarily configured for vaporizing the tissue.

In some embodiments, a control unit <NUM> is configured for switching between a thermal heating mode and an RF energy transmitting mode, for example activated by an electrical switch which may be operated by a user. If an RF energy transmitting mode is selected, RF energy generated by RF generator <NUM> is transmitted by array <NUM> into the tissue to cause ablation. If a thermal mode is selected, the vaporizing elements <NUM> are heated by a heating element <NUM> to vaporize the tissue. In some embodiments, both modes are activated simultaneously.

A system comprising an RF generator may be particularly useful in fractional skin resurfacing applications.

In some embodiments, the system comprising an RF generator is operated at a cyclic movement profile, for example utilizing a camshaft mechanism as described herein.

<FIG> illustrates a foil for vaporizing tissue, according to some embodiments of the invention.

In some embodiments, for example as described hereinabove, a size of a crosswise surface of a vaporizing element contacting the tissue is relatively small, for example if the element is shaped to penetrate to a certain depth in the tissue, a length of the element is significant. In some embodiments, a surface of the vaporizing element contacting the tissue is relatively large, for example if the element is shaped as a foil, such as a planar foil.

In some embodiments, a vaporizing element is shaped in a planar configuration having a small thickness, such as a foil <NUM>, for vaporizing a superficial crater <NUM> adjacent a surface of tissue <NUM>. A depth of crater <NUM> may range between, for example, <NUM>-<NUM>.

In some embodiments, foil <NUM> is heated by a wire <NUM>, for example a copper wire. Optionally, wire <NUM> is mounted on a surface of foil <NUM> facing away from the tissue. Optionally, wire <NUM> is embedded within foil <NUM>. In some embodiments, wire <NUM> is coated by an electrically insulating material. The ends of wire <NUM> are connected directly or indirectly (for example through an additional wire) to a power source. In some embodiments, the power source is a low voltage power source, such as a <NUM>-<NUM> V battery <NUM>.

In some embodiments, a frame <NUM> is provided for holding foil <NUM>.

Optionally, since foil <NUM> is relatively light, for example weighing less than <NUM> gram, frame <NUM> ensures full contact between the surface of foil <NUM> and the tissue. In some embodiments, foil <NUM> is held at a slightly concave position, so that frame <NUM> does not contact the tissue.

In some embodiments, frame <NUM> is adapted for heating foil <NUM>, for example by the frame being coupled to a heating element.

In some embodiments, frame <NUM> is attached to a spring <NUM> for advancing and retracting foil <NUM>. Additionally or alternatively, a coil and magnet assembly are utilized for moving foil <NUM>. In some embodiments, spring <NUM> is configured performing a single oscillation upon activation.

In some embodiments, foil <NUM> comprises an electrically insulating coating, for example glass or Aluminium Oxide coating. In some embodiments, the coating comprises chrome nitride, and/or aluminium nitride.

In some embodiments, a safety mechanism is provided. Once foil <NUM> contacts tissue <NUM> and thermal energy is depleted to vaporize the tissue, a contact between the power source such as battery <NUM> and heating wire <NUM> is disconnected. Optionally, once foil <NUM> is retracted from the tissue, the contact is re-established and wire <NUM> is heated again. Disconnection and/or reconnection of the power source are performed mechanically, and/or electrically, for example using a transistor.

In some embodiments, grounding <NUM> is provided.

In some embodiments, a surface area of foil <NUM> ranges between <NUM>^<NUM> - <NUM>^<NUM>.

In some embodiments, foil <NUM> is shaped as a thin strip, for example having a width of <NUM>. Optionally, in that case, foil <NUM> functions as a heating wire, and may conduct current. To eliminate current conductance into the tissue, foil <NUM> is coated by an electrically insulating material. Additionally or alternatively, a relatively low voltage power source is used.

In some embodiments, foil <NUM> is made of stainless steel or titanium.

Optionally, foil <NUM> is manufactured and/or applied to the vaporizing element using electroplating and/or electropolishing techniques. In some embodiments, foil <NUM> is made of glass.

Foil <NUM> may be particularly useful in skin treatments such as exfoliation and/or micro - dermabrasion, often performed by cosmeticians. The foil can be used for treating thin surface layers of skin tissue, for example around the eyes, neck, and hands.

The following is an exemplary parameter calculation of an application comprising a use of a thin foil for treating a surface layer of skin.

In this example, a foil made of glass (with a heat conductance coefficient of ~1W/mdegC) is used. The thickness of the foil is <NUM>, the volume is <NUM>^<NUM>, and the weight (M) is <NUM> grams.

A spring with a constant k=<NUM> N/m and an oscillation amplitude of X=<NUM> is used. A duration of a single oscillation is T~<NUM> msec.

The foil and spring assembly are configured for pushing the skin to a distance of Y= <NUM> in a single oscillation.

The dwelling time of the foil within the tissue, using the described assembly, can be calculated by the following equation: t=<NUM>* , for example in this case t=2msec.

In the above described conditions, the depth of a crater formed in the tissue is approximately <NUM>. (A depth of the outermost layer of the skin, the stratum corneum, is estimated at <NUM>.

To calculate a thickness of a layer (Z) in which heat is dissipated from a location in the glass foil heated to the highest temperature to a location of the tissue surface, the following equation may be applied: Z= where:.

For a dwelling time of the glass foil within the tissue of 2msec, as shown above, the calculated thickness of the heat dissipation layer is Z~<NUM>.

The amount of thermal energy stored in a <NUM> of glass, at a temperature of <NUM> degrees, obtained by multiplying the heat capacity (C) by the temperature, is <NUM> J.

Therefore, is it shown that during a <NUM> msec dwelling period, thermal energy of 4J can be depleted by the foil to the tissue, in order to vaporize the tissue. Since the energy required to vaporize water is -3000J/cm^<NUM>, an energy of 4J is capable of vaporizing a volume of <NUM>*<NUM>^-<NUM>, therefore a crater having a depth of <NUM> can be formed, (assuming square dimensions of the crater and the vaporizing foil).

<FIG> shows an exemplary configuration of a planar vaporizing element <NUM>, being held by a frame <NUM> (only a portion of the frame is shown), according to some embodiments of the invention.

In some embodiments, foil <NUM> is attached to frame <NUM> in a way that a concave contour of the foil is formed. During operation, it is possible that the rods of frame <NUM> absorb at least some of the heat from foil <NUM>. Over time, the rods of frame <NUM> may heat to a higher temperature than the rest of foil <NUM>, and possibly cause overheating at the edges of foil <NUM>. To prevent overheating of the crater borders, the presented configuration can be utilized to lift the edges of foil <NUM> away from the tissue during treatment.

<FIG> is a drawing of a hand held tissue vaporization device, according to some embodiments of the invention.

In some embodiments, an assembly of one or more vaporizing foils for example as described above in <FIG> is incorporated within a hand held device. In some embodiments, a distal portion of the hand held device (facing the tissue), comprises one or more wheels <NUM>. Optionally, a user slides the device on a surface of the tissue, for example the skin. A diameter of wheel <NUM> can be configured to advance a vaporizing foil <NUM> a certain distance, for example <NUM>, <NUM>, <NUM>, <NUM>. In some embodiments, a lever and/or cable <NUM> is provided so that rotation of wheels <NUM> applies force onto spring <NUM>, which in turn pushes foil <NUM> towards the tissue. Optionally, lever <NUM> retracts the spring so that in between treatments, foil <NUM> is positioned away from the tissue.

A potential advantage of using a device comprising an advancement mechanism includes treating large surface area, such as facial skin.

<FIG> shows a device for vaporizing craters in tissue, according to some embodiments of the invention. <FIG> illustrates a device configured for rolling over a surface of the tissue. In some embodiments, the device comprises at least one wire <NUM> for vaporizing a narrow, elongated crater. In some embodiments, a heat capacity of wire <NUM> is high enough to enable vaporization of craters having a depth of <NUM>-<NUM>.

In some embodiments, the wire is a metallic wire, for example made of tungsten, stainless steel, and/or copper. In some embodiments, wire <NUM> is coated by a thin layer of glass or ceramics. In some embodiments, a diameter of wire <NUM> ranges between <NUM>-<NUM>. A length of wire <NUM> may range between <NUM>-<NUM>, depending on the type of application.

In some embodiments, one or more wires <NUM>, for example <NUM> wires as shown in this figure, are stretched between two plates <NUM>. Optionally, the wire is tightly stretched over the plates, for example to prevent it from deforming during operation.

In some embodiments, a plate <NUM> is connected to a wheel <NUM>, for enabling rolling of the device over a surface of the tissue <NUM>.

In some embodiments, wire <NUM> is attached, for example in opposite ends, to oppositely charged electrodes <NUM>. Optionally, electrodes <NUM> are fixed in place with respect to wheels <NUM>. A current conductive structure such as brush-like structure <NUM> having end points at point A and point B may be attached to each electrode. Electrodes <NUM> are connected to a power source <NUM>, for example a battery.

During operation of the device, rotation of wheels <NUM> causes the spinning of plates <NUM>. As wire <NUM> contacts structure <NUM>, for example at point A, wire <NUM> completes the electrical circuit, and current is conducted between electrodes <NUM> through wire <NUM>. In some embodiments, point B is located close to the tissue <NUM>, for example less than <NUM> away from the tissue, and as wire <NUM> advances through structure <NUM> between points A and B (during the circular motion) it is heated, for example to <NUM>-<NUM> degrees Celsius, to vaporize the tissue. Optionally, once wire <NUM> disengages point B, current is no longer conducted through wire <NUM>.

Optionally, wire <NUM> cools as it rotates, for example until reaching point A again. A potential advantage of disconnecting wire <NUM> includes limiting the amount of thermal energy that is delivered to the tissue.

In some embodiments, multiple wires used, and a distance between craters produced in the tissue is determined according to the number of wires and/or an advancing distance of the device, for example an advancing distance during a complete rotation of the wheels.

In some embodiments, the tissue is cooled after retraction of the wire <NUM>.

Optionally, cooling is performed by blowing air, for example as shown at <NUM>. Additionally or alternatively, cooling is performed by blowing a liquid mist, and/or by spraying liquid, and/or by placing a cold metallic plate on the tissue, and/or by a thermoelectric chiller.

In some embodiments, a motor is connected to the device. Optionally, the motor is configured for advancing the device at a certain velocity, for example a constant velocity of <NUM>-<NUM>/sec.

An exemplary device may include wheels and/or plates having a diameter of <NUM>, configured to roll a distance of ~<NUM> during a single rotation (by having a circumference of ~<NUM>). A plurality of wires, for example <NUM>, <NUM>, <NUM>, <NUM>, <NUM> wires or intermediate, larger or smaller number of wires, are stretched between the plates, for example with a <NUM> interval between them. A diameter of each wire is, for example, <NUM>. By rolling the device at a velocity of <NUM>/sec over the tissue, such as skin, a duration of contact of each wire with the skin is <NUM>µsec. Elongated, narrow craters, for example having a width of <NUM>, are formed every <NUM> in the tissue.

Optionally, a depth of the craters does not surpass the stratum corneum layer of the skin.

Parameters such as wire length and/or diameter and/or a number of wires and/or advancing distance and/or advancing velocity can be selected according to the type of application. For example, for treating scars, a wire length ranging between <NUM>-<NUM> is preferable. In some embodiments, different wires on a device have different lengths and/or widths, for producing a varied lesion pattern.

In some embodiments, at least a portion of the device, for example the wires, are detachable, and can be disposed of.

<FIG> illustrates the use of a vaporizing element, or an array of vaporizing elements, for penetrating through a keratin layer of the nail, according to some embodiments of the invention.

Formation of craters through a keratin layer of the nail may be useful in treatment of onychomycosis, where liquid medication is applied to the nail to treat a fungal infection. As the keratin layer can be as thick as <NUM>-<NUM>, it may constitute a barrier which prevents the medication from penetrating the nail and attaining the surface of the infected underlying skin.

<FIG> illustrates vaporizing elements <NUM> configured for vaporizing craters or holes <NUM> through the nail <NUM>. In some embodiments, the vaporizing elements are shaped as cylindrical rods, pyramids, conical rods, or a combination thereof.

An optional treatment temperature profile used for vaporizing the keratin layer ranges, for example, between <NUM>-<NUM> degrees Celsius or higher. It is noted that fast heating of the elements may be significant, since a lower temperature, such as <NUM> degrees Celsius, will cause melting of the keratin layer as opposed to vaporization. If keratin is melted, it may become an additional barrier, interfering with the application of medication to the tissue underneath. In some embodiments, a treatment duration ranges between <NUM>-<NUM> msec.

The inventors have conducted an experiment where an array of pyramidal gold coated copper tips, having a base width of <NUM>, were heated to a temperature of <NUM> degrees Celsius and applied over a surface of a nail for a <NUM> msec duration. A crater having a depth of <NUM> was formed in the keratin layer.

In some embodiments, a single vaporizing element can be assembled in a pen-like housing, for example comprising a push-down button for a user to apply the element over the surface of the nail. Once one or more craters are formed, medication such as liquid medication can be applied, and pass through the formed craters to treat infected tissue.

<FIG> illustrates the use of a vaporizing element or an array of vaporizing elements, to treat scars in tissue, according to some embodiments of the inventions.

In some embodiments, the vaporizing array <NUM> is applied over scarred tissue <NUM>. In some embodiments, repetitive treatments are applied for gradually vaporizing the scar tissue, layer by layer. A time interval between repetitive treatments may range between <NUM> day - <NUM> months, depending on the type of tissue to be treated. In some embodiments, the time interval between treatments is determined such that a rate of formation of a new scar is smaller than the rate in which the old scar is vaporized, to prevent formation of a new scar.

In some embodiments, due the high temperature, such as <NUM> degrees Celsius, carbon particles which may reside on the walls of a vaporized crater are oxidized and transformed into CO2 vapours, leaving the crater walls are char-free. Char-free crater walls may further promote healing of the tissue.

In some embodiments, the vaporizing elements used for scar treatment have a relatively flat and/or slightly rounded tip, to prevent unwanted penetration to a deeper layer of the scar tissue.

In some embodiments, a dwelling duration of the vaporizing elements in the tissue ranges between <NUM>-<NUM> msec.

In some embodiments, topical medication is applied to exposed scar tissue, for example applied before and/or after the treatment. It is noted that medication can be applied to any type of holes produced in the tissue, and not only to exposed tissue of scars. In some embodiments, medication comprises steroids, which may accelerate healing of the treated tissue such as scar tissue.

<FIG> are photographs acquired <NUM> days following fractional skin resurfacing using vaporizing arrays made of different materials, according to some embodiments of the invention.

<FIG> shows arm skin treated with an array of pyramidal vaporizing elements made of stainless steel. <FIG> shows arm skin treated with an array of pyramidal vaporizing elements made of ALN.

The dimensions of a vaporizing element were a <NUM> base width, a <NUM> length (as measured from the plate to the distal end of the element), and a <NUM> width of the surface at a distal tip of the element. During treatment, both arrays were heated to a temperature ranging between <NUM>-<NUM>.

The duration of contact with the tissue ranged between <NUM>-<NUM> msec for the stainless steel array, and <NUM>-<NUM> msec for the ALN array.

The darkened spots <NUM> indicate locations of the formed craters, in which a crusting began to form during the healing. It is suggested that stainless steel elements can be used for achieving a mild treatment, while ALN can be used for a more aggressive treatment.

<FIG> shows an exemplary prism shaped vaporizing tip <NUM>. In some embodiments, a length <NUM> of the element ranges between <NUM> to <NUM>.

Optionally, an array of prism shaped elements comprises, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or any other number of prism shaped element aligned in parallel to each other. Optionally, the array of prism shaped elements forms elongated craters in the tissue. A potential advantage includes relatively high compliance of the treated tissue to stretch in a perpendicular orientation with respect to the formed elongated craters, and may affect drug delivery to the tissue, as will be further elaborated. Additionally or alternatively, in some embodiments, a vaporizing element may take a parallelepiped form.

<FIG> is an exemplary method for vaporizing tissue, such as skin, comprising the application of a vaporizable substance to the tissue prior to treating. In some embodiments, (<NUM>), a layer of vaporizable substance such as water and/or gel, for example water based gel, is applied to the tissue. The water and/or gel may form a relatively homogenous surface on the tissue location intended for treatment, for example relative to the direct placing on skin tissue. Additionally or alternatively, the water and/or gel adhere to the surface of the tissue so that they match a topography of the surface. The vapours of water and/or gel are safe to the patient and medical personnel and thus these substances are suitable for use as vaporizable substances.

In some embodiments, the thickness of the vaporizable layer ranges between <NUM>-<NUM>, such as <NUM>, <NUM>, <NUM>. Craters can they be vaporized in the gel covered tissue (<NUM>), for example using one or more vaporizing elements, optionally arranged in an array. Optionally, the applied substance is vaporized before the tissue is vaporized. One of the advantages of applying a substance such as water or gel may include controlling a depth of vaporization, optionally reducing the need of accurate control of movement of the vaporizing elements with respect to the tissue. For example, by applying a <NUM> thick layer of gel, and setting the vaporizing elements (e.g. using a control unit configured for activating the array) to vaporize a depth of <NUM>, <NUM> deep craters will be formed in the tissue. In some embodiments, application of gel is activated and/or controlled by the control unit. Optionally, the control unit is configured for determining a thickness of the gel.

<FIG> show an exemplary movement profile of an array of vaporizing elements and/or a single vaporizing element, comprising a vertical velocity component v1, and a horizontal velocity component v2.

The movement profile generally described herein may be particularly useful in vaporization of the stratum corneum layer, which is the outermost layer of the epidermis. A potential advantage may include vaporizing the stratum corneum layer without damaging the epidermis layers underneath.

<FIG> shows an embodiment in which an array of vaporizing elements <NUM>, optionally configured at a distal end of a hand held vaporization device, is advanced towards the tissue (e.g. skin) <NUM>. In some embodiments, for example prior to contact with the tissue, the array is caused to slide in a horizontal direction, for example using a lever and/or motor and/or wheels, or other means suitable for advancing the array in parallel to the tissue. In some embodiments, by moving the array parallel to the tissue, a treated area may be shaped, for example, as a square (for example having an area of <NUM> X <NUM>^<NUM>, a size of <NUM> X <NUM>^<NUM>, a size of <NUM> X <NUM>^<NUM> or intermediate, larger or smaller areas), a rectangle (for example having an area of <NUM> X <NUM>,<NUM>^<NUM>, <NUM> X <NUM>^<NUM>, <NUM> X <NUM>^<NUM>, or intermediate, larger or smaller areas), or other shapes thereof. In some embodiments, the parallel movement is activated prior to contact with the tissue, for example when a distal tip of the vaporizing elements is only a small distance above the tissue, such as <NUM>, <NUM>, <NUM> above the tissue. Optionally, the horizontal movement is terminated once the vaporizing elements are lifted away from the tissue.

The embodiment shown at <FIG> includes a single vaporizing element, for example shaped as a rod <NUM>. Optionally, when no horizontal movement is applied (i.e. V2=<NUM>), a maximal penetration depth H of the element ranges between <NUM>-<NUM>, for example <NUM>, <NUM>, <NUM> or intermediate, larger or smaller depths. The treated surface area of the formed crater may be determined by a diameter D of rod <NUM>, for example ranging between <NUM>-<NUM>, such as <NUM>, <NUM>, <NUM> or intermediate, larger or smaller diameters. It is noted that D may represent not only a diameter but any width of the vaporizing element, for example if the element comprises a square or rectangular cross section profile.

<FIG> illustrates a movement pattern of a vaporizing rod <NUM> for example as shown in <FIG>, comprising a horizontal velocity component.

Optionally, the horizontal velocity is constant. Alternatively, the horizontal velocity varies, for example increasing between a point of initial contact with tissue and a point of disengaging the tissue.

In some embodiments, the horizontal movement of rod <NUM> forms a crater that smears across the tissue. Optionally, penetration depth H is reduced. For example, if the horizontal width of the formed crater is the diameter D multiplied by a factor N, for example ranging between <NUM>-<NUM> such as <NUM>,<NUM>, <NUM>, or intermediate, larger or smaller values, the penetration depth H will optionally be reduced by the same factor N, arriving at a penetration depth of H/N.

In the following numerical example, diameter D=<NUM>, penetration depth H (without applying horizontal velocity)= <NUM>, and a duration of contact with the tissue =<NUM> msec. Optionally, by applying a horizontal velocity of v2=<NUM>/sec (<NUM>/<NUM> msec), a width of the formed crater increases during a contact time period of <NUM> msec to <NUM>, for example instead of <NUM> which would have been formed if no horizontal velocity was applied. Since the dwelling time on an area of <NUM> is <NUM> msec, a factor of N=<NUM> is obtained. Respectively, penetration depth H is reduced by N=<NUM>, arriving at <NUM>.

A potential advantage of moving a vaporizing element (or an array of vaporizing elements) horizontally may include increasing the precision of vaporization, for example, in the above described example, a device suitable for vaporizing craters having a depth of <NUM> is capable of vaporizing a depth of only <NUM> if an horizontal velocity component is added, thereby increasing the tolerance.

Optionally, such a device would be suitable for treating the stratum corneum without damaging deeper tissue layers, since a thickness of the stratum corneum of the skin is approximately <NUM>.

In some embodiments, a controller configured for operating the device is configured for selecting and/or modifying, automatically or by input received from a user, one or more parameters such as the penetration depth, a duration of contact with tissue, a vertical and/or horizontal velocity. Optionally, the controller is configured for selecting a size of the vaporizing element to be used. Optionally, the controller is configured for selecting and combining two or more parameters for affecting a third parameter, for example controlling the dwelling time of the element over a tissue location by selecting a horizontal velocity and and/or a size of the vaporizing element. In some embodiments, the controller is configured for applying treatment in pulses, for example for obtaining a deeper penetration depth is required (e.g. <NUM> instead of <NUM>).

The inventors have shown in experiments that in the treatment of skin, relatively small or no resistance of the tissue is encountered when moving the vaporizing element(s) horizontally across the skin. It is suggested that a sliding movement of the vaporizing element(s) across the skin is enabled, at least in part, by the elastic properties of the skin.

<FIG> show an implementation of horizontal movement to a hand held device <NUM>. Device <NUM> shown in <FIG> comprises a set of wheels <NUM>, configured to roll across the tissue. Optionally, the movement is motorized by a motor such as a DC or step motor. Optionally, the movement is controlled by a microprocessor. The device shown at <FIG> comprises a distal cup structure <NUM> which is placed on the tissue. Optionally, vaporizing elements <NUM> can pass through an opening <NUM> or through designated holes in cup <NUM>. In some embodiments, a solenoid <NUM> (or any spring or motor suitable for creating horizontal movement) is coupled to device <NUM> to apply a horizontal force F for pushing the array across the tissue.

<FIG> provides an exemplary quantification calculation of the force F required for moving an array of vaporizing elements horizontally, for example for treating a stratum corneum layer of the skin. In an embodiment, force F is applied before contact is made between vaporizing elements <NUM> and tissue <NUM>, as shown in the array position labelled A. Optionally, at position A, the horizontal velocity v2 =<NUM>. After moving the array by a distance X, reaching position B, the velocity is increased to a maximal value v2=<NUM>/sec. Optionally, the velocity remains constant during vaporization. If a weight of device <NUM> is M, (for example M=<NUM> gr), the horizontal acceleration of array <NUM> will be F/M. A duration labelled t which is the time between position A and position B of the array fulfils the following equations: <MAT> and <MAT> therefore <MAT>.

For values of M=<NUM> gr, v2=<NUM>/sec, X= <NUM>, the required force F is equal <MAT>.

In another example, wherein a single elongated vaporizing element in the form of a wire, for example having length of <NUM> and a diameter of <NUM>, the force F required for obtaining a horizontal velocity of <NUM>/sec for a handheld device weighing <NUM> gr, for a dwelling time of <NUM>µsec will be <NUM> gr force.

<FIG> shows an embodiment comprising one or more piezoelectric bimorph transducers <NUM>. In some embodiments, array <NUM> is coupled to one or more thermally insulating rods <NUM>, which are also in contact with transducer <NUM>.

Optionally, by electrically activating transducer <NUM>, the transducer is deformed to bend towards heating element <NUM>, establishing electrical contact between the vaporizing elements of array <NUM> and heating element <NUM>. Optionally, transducer <NUM> is connected to a driving rod <NUM>, for example through frame <NUM>. In some embodiments, by driving rod <NUM> in the distal and/or proximal directions (for example with the aid of a motor or spring, not shown in figure), heating element <NUM> is raised or lowered simultaneously with the movement of piezoelectric transducers <NUM>.

In an embodiment, an assembly for example as described, comprising heating element <NUM>, piezoelectric transducers <NUM>, and array <NUM> is lowered to a position in which the tips of array <NUM> are in proximity to the tissue, yet not touching the tissue, for example the distal tips of the vaporizing elements of array <NUM> are positioned <NUM> above a surface of the tissue. Optionally, at this point, as shown in <FIG>, array <NUM> is in contact with heating element <NUM>, which heats the vaporizing elements to a temperature of, for example, <NUM> degrees Celsius. In some embodiments, a distance between the array and the tissue is identified by a controller.

Optionally, the controller is configured to activate the transducers based on the distance indication, for example by reversing a polarity of the applied potential. In some embodiments, as shown in <FIG>, the transducers deform in response to the applied voltage, de-coupling array <NUM> from heating element <NUM>. Array <NUM> is advanced in the distal direction so that the vaporizing elements penetrate through the tissue to vaporize it. A potential advantage of operating the array with the aid of piezoelectric transducers may include a short response time, enabling, for example, vaporization of the stratum corneum during <NUM>µsec or less, for example to a depth of <NUM> with an accuracy of approximately ±<NUM>. Once the treating period is over, the controller may again reverse the polarity of the voltage applied to the transducer, re-establishing contact between array <NUM> and heating element <NUM>.

In an exemplary embodiment, heating element <NUM> and array <NUM>, while being coupled to each other, are moved to a distance of <NUM>-<NUM> above a surface of the skin, within a time period of, for example, <NUM> msec. The assembly is maintained at this position for a time period short enough so as to reduce or prevent damage to the skin due to infrared radiation from the heated vaporizing elements, for example <NUM> msec. In some embodiments, the piezoelectric transducer may comprise the following dimensions: a length L of <NUM>, a width W of <NUM>, and a thickness T of <NUM>. The deflection of the transducer is given by <NUM>*<NUM>^-<NUM>*L^<NUM> meter/volt, namely <NUM> for <NUM> volt or <NUM> for <NUM> volt. The resonance frequency of the transducer is, for example, <NUM>. Optionally, when activating the transducer at its resonant frequency, a single oscillation of the array is about <NUM> msec long. For an oscillation amplitude of <NUM> and oscillation time period of <NUM> msec, a dwelling duration of the array when reaching a penetration depth of <NUM> is less than <NUM>µsec. By varying the electrical potential for activating the transducer, the oscillation amplitude may be modified.

In some embodiments, as shown in <FIG> a vaporizing element <NUM> is formed of a biocompatible material <NUM>, such as titanium or stainless steel, and a high conductivity core <NUM>, for example comprising copper. In some embodiments, core <NUM> is shaped as a plug embedded within the element, for example a pyramidal element as shown in this figure. Optionally, the biocompatible layer <NUM> is coated by a thin layer, for example less than <NUM> thick, of titanium oxide. Optionally, the titanium oxide layer is capable of withstanding high temperatures such as <NUM> degrees Celsius.

In some embodiments, a thermal relaxation time of the vaporizing element along axis <NUM> (i.e. a time period required for returning to equilibrium) is reduced, if sufficient thermal contact is obtained between core <NUM> and biocompatible layer <NUM>. For example, by incorporating (e.g. using a brazing process) a core <NUM> having a length equal to a half of total length X of the vaporizing element, the thermal relaxation time may be reduced by approximately a factor of <NUM> (for example because the thermal relaxation time is proportional to X^<NUM>). Optionally, if core <NUM> is formed of copper, having a heat conductivity of approximately 400W/msec, and biocompatible layer <NUM> is formed of stainless steel or titanium, having a thermal heat conductivity of <NUM>-<NUM> W/msec, an effective thermal conductivity of element <NUM> is approximately <NUM> W/msec.

<FIG> shows an embodiment in which core <NUM> is formed of a material of high thermal conductivity, such as copper, coated by a thin biocompatible metallic sheet <NUM>, for example made of titanium and/or stainless steel. Optionally, sheet <NUM> is manufactured according the shape of core <NUM> of the vaporizing elements. Optionally, sheet <NUM> comprises a constant thickness. Alternatively, sheet <NUM> comprises a varying thickness. Optionally, sheet <NUM> is sized to complete predetermined dimensions of the vaporizing element, for example having a thickness of <NUM>. In some embodiments, sheet <NUM> is formed with a thickness of <NUM>, <NUM>, <NUM>, or intermediate, larger or smaller thicknesses. In some embodiments, sheet <NUM> is produced using a coining process. Optionally, sheet <NUM> is attached onto core <NUM> by application of pressure. Optionally, sheet <NUM> is brazed onto core <NUM>, for example brazed at a high temperature of <NUM> degrees Celsius, to enhance the contact between the materials for increasing the thermal conductivity,.

In some embodiments, craters of various depths are produced by vaporizing elements having different lengths and/or widths. Optionally, different lengths and/or widths of the elements are obtained by using a sheet <NUM> that is formed with a varying thickness.

In some embodiments, for example as shown in <FIG>, sheet <NUM> does not contact plate <NUM> onto which the vaporizing elements are mounted. A potential advantage may include a simpler mounting process of sheet <NUM> onto the cores <NUM> of the vaporizing elements, which may the area of the sheet in contact with the core and enhance the coupling between them. Optionally, the mounting is performed by brazing, for example using an oven heated to approximately <NUM> degrees Celsius. It is possible that if air is trapped between the core and the sheet, it flows to space <NUM> formed between the sheet and the plate.

It is expected that during the life of a patent maturing from this application many relevant vaporizing arrays and/or elements will be developed and the scope of the term vaporizing arrays and/or elements is intended to include all such new technologies a priori.

Claim 1:
A device for vaporizing tissue, comprising:
an array of vaporizing elements (<NUM>,<NUM>) comprised on a plate (<NUM>), said array of vaporizing elements formed of a first material of high thermal conductivity, said first material having a thermal conduction coefficient greater than <NUM> Watts per degree Kelvin per meter;
characterized in that said device further comprises:
at least one middle layer (<NUM>) coating said first material for maintaining said high thermal conductivity; and
a biocompatible titanium layer (<NUM>) coating said at least one middle layer which remains biocompatible at a temperature of between <NUM>-<NUM> degrees Celsius,
wherein said biocompatible titanium layer reduces diffusion of said first material and said at least one middle layer when said array of vaporizing elements is heated to a temperature of at least <NUM> degrees Celsius.