Applicator

Abstract

Disclosed is an applicator or handpiece configured to apply treatment energy to a segment of skin located in a tissue or skin treatment plane. The treatment energy could be RF energy, applied by a pair of bipolar RF electrodes or optical energy. The applicator includes an optical system configured to form a rectangular spot and homogenize the optical energy distribution.

Claims

1. An applicator with a skin cooling arrangement, comprising: a housing and a support structure extending from distal end of the housing, the support structure includes at least one cooling fluid conducting channel; a transparent window mounted on the support structure the window includes at least one cooling fluid conducting channel being in fluid communication with the at least one fluid conducting channel in the support structure; and wherein the transparent window cools treated tissue area being in contact with the transparent window.

2. The applicator according to claim 1, further comprising a pair of bipolar RF electrodes mounted on the support structure and wherein a pair of bipolar RF electrodes is configured to apply RF energy to tissue located in tissue treatment plane.

3. The applicator according to claim 1, wherein an optical system configured to receive a beam of optical energy from a source of optical energy and convey it to tissue located in a tissue treatment plane and wherein a tissue treatment plane is located between a pair of bipolar RF electrodes.

4. The applicator according to claim 1, wherein cross section of the cooling fluid conducting channel made in the transparent window is one of a group consisting of a round, elliptical, oval and cross section having a relatively low fluid flow resistance.

5. The applicator according to claim 1, wherein the transparent window includes a hollow cavity being in fluid communication with fluid conducting channels made in the support structure.

6. The applicator according to claim 1, wherein the transparent window is made of at least one of a group of materials consisting of sapphire and quartz.

7. The applicator according to claim 1, wherein outer surface of the transparent window is in contact with tissue and defines the tissue treatment plane.

8. The applicator according to claim 1, wherein a source of optical energy provides optical energy with wavelength of 400 nm to 2000 nm.

9. The applicator according to claim 1, wherein a source of optical energy provides optical energy with fluence of 0.5 J/cm2 to 150 J/cm2.

10. The applicator according to claim 1, wherein the support structure is angled with respect to axis of symmetry of the applicator at an angle of 10 to 30 degrees.

11. The applicator according to claim 1, wherein the support structure is coaxial with axis of symmetry of the applicator.

12. The applicator according to claim 1 wherein a cooling tip has a thermal resistance of less than 1 degree Celsius per Watt of heat load.

13. The applicator according to claim 1 further including a light pipe homogenizing rod and wherein the rod is at least one of a group of light guides consisting of a tapered light homogenizing rod, a tapered optical trapezoidal prism, a tapered multi-facet optical homogenizing rod or a tapered hollow light guide with a reflective coating deposited on inner surfaces of the light guide.

14. The applicator according to claim 13 wherein the applicator includes an optical system with a pair of lenses configured to receive a homogenized beam of optical energy from light pipe homogenizing rod and image output facet of light pipe homogenizing rod to a treated skin or tissue plane located between a pair of bipolar RF electrodes and wherein an output facet of light guide has an oval shape.

15. The applicator according to claim 1, wherein the applicator includes an optical system with a pair of lenses configured to receive a homogenized beam of optical energy from light pipe homogenizing rod and image output facet of light pipe homogenizing rod to a treated skin or tissue plane located between a pair of bipolar RF electrodes and wherein an output facet of light pipe homogenizing rod has a trapezoidal shape.

17. The applicator according to claim 1, wherein the support structure is angled with respect to axis of symmetry of the applicator at an angle of 10 to 30 degrees.

18. The applicator according to claim 1, wherein the support structure angled with respect to axis of symmetry facilitates to operator a good view of a treated tissue area.

19. The applicator according to claim 1, further comprising a cooling fluid reservoir and wherein a thermoelectric element cools the cooling fluid reservoir and wherein the cooling fluid cools the support structure and a sapphire window being in contact with a tissue treatment plane.

20. The applicator according to claim 19, wherein a cooling fluid circulation is in at least one of a group consisting of continuous circulation before the tissue treatment, in course of the tissue treatment and after the tissue treatment.

21. The applicator according to claim 19, wherein a cooling fluid is forced to circulate at defined periods and wherein the forced cooling fluid circulation is configured to operate in at least 200 ms before delivery of laser energy.

Description

LIST OF FIGURES AND THEIR BRIEF DESCRIPTION

[0018] FIG. 1 is a simplified illustration of an applicator disclosed in U.S. patent application Ser. No. 14/484,302 filed on Sep. 12, 2014 and incorporated herein by reference;

[0019] FIG. 1A is a view taken along the line C in FIG. 1.

[0020] FIG. 2 is a simplified illustration of an applicator according to an example;

[0021] FIGS. 3A and 3B is an example of a transparent cooling window including cooling fluid flow conducting channels;

[0022] FIGS. 4A and 4B is an additional example of a transparent cooling window including cooling fluid flow conducting channels;

[0023] FIG. 5 is a cross section of transparent cooling window of FIG. 4 along a line indicated by arrows D-D;

[0024] FIGS. 6A and 6B is an additional example of a transparent cooling window including cooling fluid flow conducting channels;

[0025] FIGS. 7A and 7B is still an additional example of an applicator for skin treatment;

[0026] FIGS. 8A and 8B is still an additional example of a transparent cooling window including cooling fluid flow conducting channels;

DESCRIPTION

[0027] Concurrent application to the tissue or skin located in the treatment plane of RF energy and light energy allows addressing of skin or tissue layers located at different depth at one treatment. It allows reduction of each of the energies and diminishes the danger of skin burning. Appropriate cooling by a contact cooling element applied to the surface of the skin or tissue becomes even more important and is desired to prevent non-reversible damage to the dermis. The present disclosure provides effective contact cooling devices optimized for effective cooling of both the lighter and darker skin types.

[0028] The applicator also supports real time observation of visible changes in the treated skin or tissue area and facilitates the accurate placement of the applicator from one application of the skin treatment energy, to the next application of skin treatment energy.

[0029] Cooling of the tissue located in a tissue treatment plane is usually performed by cooling an applicator element being in contact with the tissue located in the treatment plane. Absence of effective cooling of the epidermis while heating the dermis and deeper skin layers during the course of optical (laser) energy treatments can cause undesired pain to the treated subject and potentially undesired skin injury. Traditional cooling modes—such as topical applications, forced cold air, and contact cooling—cool imperfectly, are often too long and too deeply. Such methods force additional laser energy to be used to reheat the dermis. Therefore, either treatment fluence needs to be raised or the therapeutic value is diminished.

[0030] The authors of the current disclosure have experimentally proved that effective tissue cooling supports increase in treatment energy, shortens treatment time and leads to better treatment results.

[0031] FIG. 1 is a simplified illustration of an existing an earlier disclosed applicator. Applicator or handpiece 100 includes a housing 104 with a proximal 108 and a distal 112 end. A support structure 116 including two support columns is terminated by a frame 120 that extends from distal end 112. Support structure 116 is angled to applicator 100 axis of symmetry 134 or off normal relative to axis of symmetry 134 of applicator 100 and improves line of sight to the skin treatment plane or skin area to be treated 140. The compliment of angle 144 at which support structure 116 is angled could be 10 to 30 degrees and usually the angle could be about 15 degrees.

[0032] Frame 120 holds an easy removable and replaceable window 124. Frame 120 could have a round, elliptical or a rectangular shape. Support structure 116 and frame 120 are made of metal or other material supporting good heat or cold conducting properties. Support structure 116 and frame 120 are in thermal communication with a thermoelectric cooler 118. Replaceable window 124 could be made of sapphire or quartz.

[0033] Applicator 100 further includes an optical system 130 configured to receive a beam of optical energy 136 from a source of optical energy (not shown) and to direct the beam of optical energy 136 to irradiate the skin or tissue treatment plane 140 defined by frame 120 and being in contact with replaceable window 124 in the tissue or skin treatment plane 140. Optical system 130 of applicator 100 could further include a pair of lenses 148 configured to receive a homogenized beam of optical energy 134 and image the output facet 168 of homogenizing rod 152 to the tissue or skin treatment plane 140.

[0034] In use applicator 100 is applied to the skin or tissue treatment plane 140 and the source of optical energy could be activated to apply treatment energy to the skin or tissue treatment plane 140. Replaceable window 124 is cooled through the contact with frame 120 and being in contact with the tissue or skin treatment plane 140, windows 124 cools the skin surface located in the tissue treatment plane 140.

[0035] A cable 160 (FIG. 1 and FIG. 2) extends from proximal end 108 of applicator 100 housing 104. Cable 160 connects applicator 100 to a power supply (not shown). Housing of the power supply could also incorporate a source of optical energy and a source of RF voltage. Optical fiber guide 150 could be included in cable 160. The fiber could conduct the optical energy to applicator or handpiece 100/200/700. Alternatively, an articulated arm could conduct the optical energy to handpiece. Although not inclusive, the source of optical energy could be a suitable laser, for example, a 595 nm pulse dye laser, a 1064 nm Nd:YAG laser, or Alexandrite 755 nm laser, or a diode laser or an assembly of diode lasers with different laser diodes emitting different light wavelengths. Selection of laser depends on the desired type of treatment. The source of optical energy could be a suitable laser that provides optical energy with wavelength of 400 nm to 2000 nm. Since some of the treatment could be performed by wavelengths that are not visible, applicator 100 could also include a LED 158 illuminating the located between RF electrodes tissue or skin treatment area 140.

[0036] FIG. 1A, is a view of the applicator 100 distal end 112 as viewed from the direction indicated by arrow C (FIG. 1). A pair of bipolar RF electrodes 128 could be located on distal end 112 of housing 104. Electrodes 128 could be configured to apply RF energy to tissue 164 located in tissue treatment plane 140. Electrodes 128 could be solid metal electrodes mounted on frame 120 or deposited directly to the transparent window 120. Optical system 130 could be configured to receive a homogenized beam of optical energy 134 from light pipe homogenizing rod 152 and image output facet 168 of light pipe homogenizing rod 130 to a treated skin or tissue plane 140 located between the pair of bipolar RF electrodes 128.

[0037] Depending on the desired skin treatment, type of the skin, intensity of the energy applied to the skin or tissue treatment plane 140 the cooling by cooling plate 124 could be not sufficient and still cause an epidermal injury. The effectivity of the contact cooling devices could be further optimized to make them just as effective for both the lighter and darker skin types.

[0038] FIG. 2 is a simplified illustration of an applicator according to an example. Support structure 216 of applicator 200 includes two support columns 214 that extend from distal end 212 of handpiece or applicator 200.

[0039] Support structure 216 holds a transparent to treatment radiation window 224. Support structure 216 could include a slot 220 of rectangular or oval shape. Slot 220 is adapted to receive transparent window 224 made of sapphire or quartz. Support structure 216 is made of metal or other material supporting good heat or cold conducting properties, and RF electrical conducting properties. Support structure 216 includes one or more cooling fluid conducting channels 218 (shown in broken line.) receiving a cooling fluid from a cooled or chilled reservoir 204. Cooling fluid conducting channels 208 made in transparent window 224 are in fluid communication with fluid conducting channels 218 (shown in broken lines) made in the support structure 216. Fluid conducting channels 218 made in the support structure 216 and are in fluid communication with a reservoir 204 of cooling fluid. The flow of cooling fluid into the support structure and transparent window 224 with fluid conducting channels 208 is schematically shown by arrows IN and OUT. The fluid conducting channels 208 could be configured to conduct the cooling fluid to almost the entire surface of the transparent window 224 or at least to a part of the surface of the transparent window. A thermoelectric chiller or vapor compressor chiller (not shown) could be used to cool and maintain at a desired temperature cooling fluid in the reservoir 204.

[0040] Applicator 200 further includes elements similar or identical to the ones included in applicator 100. These elements are marked by identical referral numbers. An optical system 130 configured to receive a beam of optical energy 134 from a source of optical energy (not shown) directs the beam of optical energy 134 to irradiate the skin or tissue treatment plane 140 defined by transparent window 224. Surface 242 of the outer side of the transparent window is in contact with the tissue or skin treatment plane 140. Beam of optical energy 134 could be conducted from a source of optical energy (not shown) for example, by a fiber optics guide.

[0041] FIGS. 3A and 3B is an example of a transparent window including cooling fluid conducting channels. Transparent window 224 (FIG. 3A) with cooling fluid conducting channels 208 delivers cooled or chilled fluid that could be water directly to and through the sapphire window 224 placed in contact with skin (see FIG. 2.) The proximity of the cooled or chilled water with the skin surface reduces the thermal resistance of the chilling/cooling tip. The thermal resistance just under 1 K/W is easily obtained by optimization of the chilled tip design. (In comparison for the thermoelectric cooler (TEC) cooled chilled tip designs, thermal resistances are typically around 8 K/W.)

[0042] In one example, transparent window 224 could include one or more separate cooling fluid conducting channels 208. The support structure 216 (FIG. 2) could be constructed to support flow of the cooling fluid in the same direction. In general, the fluid conducting channels 208 (FIG. 3B) are positioned near to but outside of the transmitted optical path to avoid lensing affects at the interface due to unmatched refractive indices between the fluid and transparent window material.

[0043] FIGS. 4A and 4B is an additional example of a transparent window including cooling fluid conducting channels. Fluid conducting channels 408 are located along the perimeter of transparent sapphire window 424. In this example all four sides of the sapphire window 424 are in direct contact with the flowing cooled or chilled water. The four sided sapphire window cooling significantly reduces thermal gradients in the sapphire window. The cross section of the fluid conducting channels 408 (FIG. 4B) could be round elliptical, oval or any other cross section having a relatively low fluid flow resistance.

[0044] FIG. 5 is a cross section of cooling window 424 along line indicated by arrows D-D. The figure illustrates the geometry and rounded corners of fluid conducting channels 408. One of more fluid conducting channel can be positioned within the optical path although care should be taken that the cooling fluid and optical window material are selected to have similar refractive indices.

[0045] In another example, illustrated in FIGS. 6A and 6B transparent window 624 could include a hollow cavity 612 being in fluid communication with fluid flow conducting channels 218 made in the support structure 216. In cases where the transparent window 624 has large size, for example 40 mm or 50 mm transparent window with hollow cavity 612 could become more effective avoiding the need for multiple channels. Although, to avoid optical reflective losses, the refractive indices of the window and cooling fluid should be similar.

[0046] The transparent window 624 having a hollow cavity 612 (and other examples of the transparent windows 224, 424 and 624) can be made from a single window material piece or could be made from two separate window material pieces that are held together with a support structure using a spacer to form a gap between the windows for coolant flow. Each surface of the transparent window or windows can have anti-reflective coatings designed to minimize optical reflective losses.

[0047] Support structures 116 and 216 illustrated in FIG. 1 and FIG. 2 are angled support structure. Support structure can also be design such that it approaches the tissue treatment plane 140 from the top or bottom of the applicator 100 and 200 to avoid getting in the way of the users direct line of site of the tissue treatment plane 140. The support structure can also be design such that it has an opening or void to avoid getting in the way of the users direct line of site of the tissue treatment plane 140.

[0048] In another example illustrated in FIGS. 7A and 7B, support structure 704 is oriented generally coaxial or the axis of the support structure 704 coincides with the axis of symmetry 708 of applicator 700 and is perpendicular to the tissue treatment plane 240 (Angle 712). The support structure is an assembly of cooling fluid conducting tubes 720 or channels. The open space between the cooling fluid conducting tubes 720 that could be made of rigid material is sufficient to support unobstructed real time observation or visualization of the tissue treatment plane during cosmetic skin treatment procedures. The distal end of the support structure 704 is configured to support or hold for example a transparent window 624 (FIG. 7B) or any other window with cooling fluid conducting channels. In some examples, as illustrated in FIGS. 8A and 8B, a pair of bipolar RF electrodes could be deposited on transparent window 624 (or any other window, such as window 224 or 424) or support structure 704. The tissue treatment plane is located between the bipolar RF electrodes. The optical system of applicator 700 has no angled parts and the image of output facet 168 of light pipe homogenizing rod 152 could be of round, rectangular or even polygonal shape at the tissue treatment plane 140.

[0049] The optical energy across the tissue treatment plane 240 is homogenized. When applicator 200 or 700 is moved from one skin treatment location to another skin treatment location, the rectangular image or spot could be densely packed in the tissue or skin 164 (FIGS. 1 and 2).

[0050] In use applicator 200 or 700 is applied to the skin or tissue treatment plane and the source of optical energy is activated. Then, in order to treat an adjacent skin surface area the applicator is either continuously displaced over the skin or stepped from one skin segment to the other. The rectangular shape of the treatment optical energy spot does not force overlap between the stepped spots and also does not leave non-overlapped and not treated skin areas or segments. The cooling fluid circulation could be continuous (before the treatment, in course of the treatment and after the treatment). Alternatively, the cooling fluid could be forced to circulate at the defined periods.

[0051] In critical skin treatment applications requiring effective skin cooling such as when treating the darker skin types V and VI, each of the applicators 100/200 and 700 could be configured to operate in a treatment mode that enforces a 200 to 300 ms cool down time before delivering the laser energy. This mode is suitable for example when the applicator is used in a stamping mode and for the RF delivery tips as it measures the skin impedance via the RF electrodes. Once skin contact is detected from a change in impedance, the system controller (not shown) waits for 200 to 300 ms before delivering the laser energy. Enforced cooling guarantees effective and user-consistent skin cooling with each delivered laser pulse.

[0052] As indicated the skin treatment system could be equipped by a number of light sources, for example, lasers to treat different skin conditions. For example, a 595 nm pulse dye laser could be used to treat different vascular conditions, Alexandrite 755 nm laser could be used for hair removal, a 1064 nm Nd:YAG laser could also be effective in treatment of different vascular conditions, different laser diodes emitting different light wavelengths could be used to treat a variety of skin condition by changing the treatment optical energy wavelength and pulse duration.

[0053] The fluence of optical energy used for skin or tissue conditions treatment could be 0.5 to 150 J/cm2, pulse duration could be 100 psec to 1 sec, the spot size could be 10×10 mm or even 20×20 mm Other sizes and relations between the spot size parameters could be considered including a rectangle such as 10×30 mm

[0054] The authors of the current disclosure are aware that some cosmetic skin treatment system claim use of square or rectangular beams produced by a square or rectangular optical prism that is placed in contact with skin by cooling the prism. Although the latter approach has the benefit of cooling the skin surface, but in order to enhance or collect the incident light the prism is covered by light reflecting coatings and obstructs the operator's field of view. Use of the present applicator provides effective cooling of the treated skin area and mitigates adverse effects caused by application to the skin of non-uniform distributed energies and in particular light energy.

[0055] The applicator or handpiece significantly improve observation of the tissue or skin treatment plane and facilitate the work of the operator or caregiver, providing unobstructed view of the tissue or skin treatment plane.

[0056] It should be recognized that a number of variations of the above-described examples will be obvious to one of ordinary skill. Accordingly, the apparatus and method are not to be limited by those specific examples and methods as shown and described herein. Rather, the scope of the product and method is to be defined by the following claims and their equivalents.