Systems and methods for tissue treatment

Abstract

A cooling element includes a frame including one or more references. The cooling element also includes a first window, the first window including a first proximal surface and a first distal surface. The first window is sealed to the frame. The cooling element further includes a second window sealed to the frame. The second window includes a second proximal surface and a second distal surface. The second window is configured to contact a target tissue or tissue adjacent to the target tissue via the second distal surface. The cooling element also includes a coolant cavity, the coolant cavity is located between the first distal surface of the first window and the second proximal surface of the second window and is configured to receive a coolant. The first window, the second window and the coolant cavity are configured to receive electrical radiation (EMR) and transmit a portion of the received EMR to the target tissue.

Description

Background Art

[0001] Various conditions can be treated by applying certain wavelengths of light or optical energy. There are many challenges in delivering energy to an appropriate target structure (e.g., tissue such as skin) without damaging tissue structures adjacent to the target structure. These challenges include delivering energy at an appropriate wavelength with sufficient fluence, and effectively and efficiently scanning the target structure with light or optical energy.

[0002] Melasma is an example of a skin disease of unknown etiology that often causes spotty hyperpigmentation in facial areas. This condition is more common in women than in men. Although the specific causes of melasma may not be well understood, the pigmented appearance of melasma may be aggravated by certain conditions, such as pregnancy, sun exposure, certain medications such as oral contraceptives, hormone levels, genes, etc. Exemplary symptoms of melasma include dark, irregularly shaped patches or spots that generally appear on the upper cheeks, nose, upper lip, and forehead. These patches often develop gradually over time. In addition to the discoloration in appearance, melasma does not seem to cause any other symptoms or other adverse effects.

[0003] Unlike the many pigmented structures that typically occur in the epidermal region of the skin (e.g., at or near the tissue surface), dermal (or deep) melasma is often characterized by the widespread presence of melanin and melanophages (e.g., including over-pigmented cells) in portions or regions of the underlying dermis. Therefore, the treatment of dermal melasma (e.g., reducing the appearance of darkened pigmented areas) can be particularly challenging because it is more difficult to contact and affect these pigmented cells and structures located deeper in the skin. Therefore, conventional skin rejuvenation treatments that primarily affect the overlying epidermis, such as facial peels (laser or chemical), dermabrasion, topical agents, etc., may be ineffective for treating dermal melasma. Summary of the invention

[0004] It has been observed that the application of light or optical energy of certain wavelengths can be strongly absorbed by pigmented cells, thereby damaging them. However, using optical energy to effectively treat dermal melasma has brought some obstacles. For example, the pigmented cells in the dermis must be targeted by sufficient optical energy of (multiple) appropriate wavelengths to destroy or damage them, which can release or damage some pigmentation and alleviate the colored appearance. However, such energy can be absorbed by the pigment (for example, chromophore) in the overlying skin tissue such as epidermis and upper dermis. This nearly surface absorption can cause excessive damage to the skin outside, and the energy transfer for the pigmented cells therein for affecting deeper dermis is insufficient. In addition, the thermal damage for the melanocytes in the base layer of the epidermis can cause the increase of melanin production, and the thermal damage causing the destruction of melanocytes may cause hypopigmentation. Therefore, it is expected that the tissue that is not targeted, especially the pigmented epidermal tissue, which is just above the dermal melasma spot, is cooled (for example, heat transfer is away from the tissue). Ideally, this cooling will be carried out simultaneously with the therapeutic radiation and above the tissue surface identical with the radiation.

[0005] A graded approach has been developed that involves applying optical energy to small discrete treatment locations on the skin separated by healthy tissue to promote healing. It may be challenging to accurately target a treatment location (e.g., located in the dermis) with the desired specificity while avoiding damage to healthy tissue surrounding the treatment location (e.g., in the epidermis). For example, this requires an optical system with a high numerical aperture (NA) in order to focus the laser beam to the treatment location. In addition, the optical system should be able to scan the focused beam over a large affected area (e.g., several square centimeters). Therefore, it is desirable to develop an optical system with a high numerical aperture and capable of scanning over a large affected area. It is also desirable to have an interface that establishes stable contact with the treatment area and stabilizes the treatment area, so that the depth of the focused laser beam can be maintained within the treatment area. In addition, it would be beneficial for the interface to cool the treatment area to prevent undesirable thermal damage simultaneously with the therapeutic radiation. At least for the reasons outlined above, improved methods, systems, and devices for EMR-based (e.g., laser-based) tissue treatment are provided.

[0006] In one embodiment, a system includes an optical element configured to receive electromagnetic radiation (EMR) and focus the EMR along an optical axis to a focal region in a target tissue. The system also includes a cooling element downstream of the optical element and configured to receive focused EMR. The cooling element includes a first window, which includes a first proximal surface and a first distal surface. The first window is sealed to a frame. The cooling element further includes a second window sealed to the frame. The second window includes a second proximal surface and a second distal surface. The second window is configured to contact a target tissue or a tissue adjacent to the target tissue via the second distal surface. The cooling element also includes a coolant cavity, which is located between the first distal surface of the first window and the second proximal surface of the second window and is configured to receive a coolant. The first window, the second window, and the coolant cavity are configured to receive electromagnetic radiation (EMR) and transmit a portion of the received EMR to the target tissue.

[0007] In one embodiment, the controller is configured to change a first distance between the focal region and the second distal surface of the second window along the optical axis by changing a second distance between the optical element and the second distal surface of the second window along the optical axis. In another embodiment, the first distance varies between a first predetermined value and a second predetermined value as the focal region traverses a treatment path in the target tissue. In yet another embodiment, the difference between the first predetermined value and the second predetermined value is less than 0.25 mm. In another embodiment, the first predetermined value is 0.001 mm and the second predetermined value is 10 mm.

[0008] In one embodiment, the controller is configured to change a first distance along the optical axis between the focal region and the second distal surface of the second window by changing a divergence associated with the EMR. In another embodiment, the system further comprises a scanner. The scanner is configured to receive a control signal from the controller and move the optical element along a first scanning path based on the control signal. In yet another embodiment, the first scanning path is substantially parallel to the second distal surface of the second window.

[0009] In one embodiment, the controller is configured to vary the intensity of the EMR radiation. In another embodiment, the controller is configured to vary the flow rate of the coolant in the coolant cavity. In yet another embodiment, the optical element has a numerical aperture (NA) in the range of about 0.1 to about 1.0.

[0010] In one embodiment, the EMR has an average power in the range of about 1 W to about 100 W. In another embodiment, the EMR comprises a pulsed laser beam having a wavelength in the range of about 400 nm to about 4000 nm. In yet another embodiment, the EMR is configured to generate a thermal ionic plasma in the focal region. In another embodiment, the cooling element further comprises a gas source configured to direct a gas to the first window, the gas configured to prevent condensation on the first window.

[0011] In one embodiment, the method includes generating focused electromagnetic radiation (EMR) and transmitting the focused electromagnetic radiation through a cooling element. The cooling element includes a first window including a first proximal surface and a first distal surface. The first window is sealed to a frame. The cooling element further includes a second window sealed to the frame. The second window includes a second proximal surface and a second distal surface. The second window is configured to contact a target tissue or tissue adjacent to the target tissue via the second distal surface. The cooling element also includes a coolant cavity, which is located between the first distal surface of the first window and the second proximal surface of the second window and is configured to receive a coolant. The method further includes directing the focused EMR to a focal area in the target tissue.

[0012] In one embodiment, generating the focused EMR includes: placing an optical lens along an optical axis of the EMR. In another embodiment, the method further includes changing the depth of the focal region in the target tissue by changing the position of the optical lens along the optical axis. In yet another embodiment, the depth of the focal region ranges from about 0.001 mm to about 10 mm.

[0013] In one embodiment, the method further comprises scanning the focused EMR along a treatment path in the target tissue. In another embodiment, the focused EMR beam is scanned along a treatment path by moving the optical element substantially parallel to the second distal end of the second window.

[0014] In one embodiment, the cooling element comprises a frame including one or more datums. The cooling element also comprises a first window including a first proximal surface and a first distal surface. The first window is sealed to the frame. The cooling element further comprises a second window sealed to the frame. The second window comprises a second proximal surface and a second distal surface. The second window is configured to contact a target tissue or tissue adjacent to the target tissue via the second distal surface. The cooling element also comprises a coolant cavity located between the first distal surface of the first window and the second proximal surface of the second window and configured to receive a coolant. The first window, the second window and the coolant cavity are configured to receive electrical radiation (EMR) and transmit a portion of the received EMR to the target tissue.

[0015] In one embodiment, the one or more references are arranged in a reference plane. The second window is arranged at a first angle with respect to the reference plane. The first angle is less than 1.0 mrad. In another embodiment, the coolant cavity includes a port configured to guide coolant from a coolant flow source to the coolant cavity. In yet another embodiment, the first window is sealed to the frame via a first seal, and the second window is sealed to the frame via a second seal. The first seal includes one or more of an adhesive, a weld, a solder, a braze, a polymer, and an elastomer.

[0016] In one embodiment, a first heat dissipation associated with the first window is lower than a second heat dissipation associated with the second window. In another embodiment, a first thickness associated with the first window is greater than a second thickness associated with the second window. In yet another embodiment, the cooling element further includes a gas source configured to direct a gas to the first window. The gas is configured to prevent condensation on the first window.

[0017] In one embodiment, the second distal surface of the second window has one or more of a flat shape, a convex shape, and a concave shape. In another embodiment, the cooling element further comprises a fastener. The fastener is configured to attach the second distal surface of the second window to the frame. In yet another embodiment, the fastener comprises at least one of a screw, a clamp, a snap, a retaining ring, and a tab.

[0018] In one embodiment, the second window comprises at least one of: sapphire, quartz, or diamond. In another embodiment, the first window is arranged at a second angle with respect to the second window, wherein the second angle is less than 10 mrad. In yet another embodiment, the second window is downstream of the first window. In another embodiment, a portion of the received EMR is transmitted to a focal region in the target tissue.

[0019] In one embodiment, a method includes directing EMR to a cooling element. The cooling element includes a frame including one or more references. The cooling element also includes a first window including a first proximal surface and a first distal surface. The first window is sealed to the frame. The cooling element further includes a second window sealed to the frame. The second window includes a second proximal surface and a second distal surface. The second window is configured to contact a target tissue or tissue adjacent to the target tissue via the second distal surface. The cooling element also includes a coolant cavity, which is located between the first distal surface of the first window and the second proximal surface of the second window and is configured to receive a coolant. The first window, the second window, and the coolant cavity are configured to receive electrical radiation (EMR) and transmit a portion of the received EMR to the target tissue.

[0020] In one embodiment, transmitting a portion of the EMR to the target tissue comprises: focusing the EMR at a focal area in the target tissue. In another embodiment, the one or more references are arranged in a reference plane. The second window is arranged at a first angle with respect to the reference plane, wherein the first angle is less than 1.0 mrad. In yet another embodiment, the coolant cavity includes a port configured to direct coolant from a coolant flow source to the coolant cavity. In another embodiment, the first window is sealed to the frame via a first seal, and the second window is sealed to the frame via a second seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The embodiments of the present disclosure will be more fully understood through the following detailed description in conjunction with the accompanying drawings, in which:

[0022] Figure 1 schematically illustrates a system for irradiating and cooling tissue according to some embodiments;

[0023] Figure 2A schematically illustrates a system for varying the working distance of a focus of an electromagnetic radiation beam according to some embodiments;

[0024] Figure 2B schematically illustrates another system for varying the working distance of a focal point of an electromagnetic radiation beam according to some embodiments;

[0025] Figure 3 schematically illustrates a system for scanning a beam of electromagnetic radiation in at least one axis according to some embodiments;

[0026] 4A to 4D schematically shown in various views a system for cooling tissue while irradiating according to some embodiments;

[0027] Figure 5 is a flow chart representing a method for irradiating and cooling tissue according to some embodiments;

[0028] Figure 6 is a schematic illustration of a laser beam focused into a pigmented area of ​​the dermis layer in the skin;

[0029] Fig. 7A is an exemplary absorption spectrum graph of melanin;

[0030] Figure 7B is an exemplary absorption spectrum graph of hemoglobin;

[0031] Figure 8 A plot illustrating the absorption coefficients of melanin and venous blood and the scattering coefficient of light in the skin versus wavelength;

[0032] Fig. 9A illustrates a graph depicting the cooling performance of a plurality of exemplary cooling elements; and

[0033] Figures 9B-9D A schematic diagram of an exemplary cooling element is illustrated.

[0034] It should be noted that the drawings are not necessarily drawn to scale. The drawings are intended to depict only typical aspects of the subject matter disclosed herein and, therefore, should not be considered to limit the scope of the present disclosure. Those skilled in the art will understand that the systems, devices, and methods specifically described herein and illustrated in the drawings are non-limiting exemplary embodiments, and the scope of the present embodiments is limited only by the claims. DETAILED DESCRIPTION

[0035] Certain exemplary embodiments will now be described to provide an overall understanding of the principles of structure, function, manufacture and use of the apparatus and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. The features illustrated or described in conjunction with an exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.

[0036] Some embodiments of the present disclosure are discussed in detail below with respect to the treatment of skin pigment conditions such as melasma to improve the appearance of such pigment conditions. However, the disclosed embodiments may be employed for the treatment of other pigment or non-pigment conditions and other tissue and non-tissue targets without limitation. Examples of pigment conditions may include, but are not limited to, post-inflammatory hyperpigmentation, dull skin around the eyes, dark circles, light brown patches, Baker's nevus, nevus of Ota, congenital melanocytic nevus, freckles / lentigos, hemosiderin-rich structures, pigmented gallstones, lutein, zeaxanthin, rhodopsin, carotenoids, biliverdin, bilirubin, and hemoglobin-rich structures, and tissue containing tattoos. Examples of non-pigment conditions may include, but are not limited to, hair follicles, hair shafts, vascular lesions, infectious conditions, sebaceous glands, acne, and the like. Examples of non-skin tissues may include, but are not limited to, soft tissues such as cartilage, mucosa, and serosa, and hard tissues such as bone and enamel.

[0037] Further, in the present disclosure, components with the same name in an embodiment generally have similar features, and therefore each feature of each component with the same name is not necessarily fully elaborated in a particular embodiment. In addition, to the extent that linear or circular dimensions are used in the description of the disclosed systems, devices, and methods, such dimensions are not intended to limit the types of shapes that can be used in conjunction with such systems, devices, and methods. Those skilled in the art will recognize that equivalent forms of such linear and circular dimensions can be easily determined for any geometric shape. The size and shape of the systems and devices and their components and their components can depend at least on: the anatomical structure of the subject in which the system and device will be used, the size and shape of the components with which the system and device will be used, and the methods and processes in which the system and device will be used.

[0038] In general, some high numerical aperture (NA) optical treatment systems are described, which can focus electromagnetic radiation (EMR) (e.g., laser beam) to a treatment area in a tissue. The focused laser beam can deliver optical energy to the treatment area without damaging surrounding tissue. The delivered optical energy can, for example, destroy the colored chromophores and / or targets in the treatment area of ​​the dermis of the skin without affecting the surrounding areas (e.g., the overlying epidermis, other parts of the dermis, etc.) or can destroy the colored chromophores and / or targets in other colored target areas of the skin or tissue surrounded by unaffected and non-target areas. In other embodiments, the delivered optical energy can result in the removal or change of tattoos, or hemoglobin-related treatments. During a typical treatment, a large amount of radiation (e.g., an average power greater than 1W, 5W, 10W, 20W, or 30W depending on the wavelength) is delivered to the tissue. These radiation levels will eventually cause the block of the tissue to heat up and may cause thermal damage. In order to prevent the block of the tissue from heating up, the tissue must be cooled. In order to make the cooling most effective, the cooling is performed at the same place and at the same time as the radiation. Previous cooling methods have performed cooling in the same place, but not at the same time (eg, cryogenic cooling). Other methods for cooling have also been performed that cool at the same time, but not over exactly the same area as irradiation.

[0039] Exemplary methods and apparatus for treating skin conditions using light or optical energy are disclosed in U.S. Patent Application Publication No. 2016 / 0199132, entitled “Method and Apparatus for Treating Dermal Melasma,” and U.S. Provisional Application No. 62 / 438,818, entitled “Method and Apparatus for Selective Treatment of Dermal Melasma,” each of which is incorporated herein by reference in its entirety.

[0040] Figure 1An exemplary embodiment of a treatment system 100 capable of irradiating and cooling tissue 101 is illustrated. An electromagnetic radiation (EMR) source 102, such as a laser, generates an EMR beam 104. According to some embodiments, the EMR beam 104 has a wavelength in a range between 100 nanometers (nm) and 15000 nm (e.g., between 400 nm and 4000 nm). An exemplary EMR source 102 can be a Q-Smart 450 from Quantel of Les Ulis, France. The Q-Smart 450 is capable of generating an EMR beam 104 (e.g., a pulsed beam) having a wavelength of 1064 nm, a pulse duration between 6 nanoseconds (nS) and 20 nS, a repetition rate of up to 40 Hz, and a pulse energy of up to 450 mJ. Another exemplary EMR source 102 is a Coherent Diamond FLQ fiber laser from Coherent of Santa Clara, California. The EMR beam 104 generated by the Diamond FLQ fiber laser can have an average power of up to 10 W, 20 W, 50 W, or 100 W, a pulse duration of about 100 nS, a pulse energy of up to 1 mJ, and a pulse repetition rate between 20 KHz and 100 KHz. The EMR beam 104 can be focused by an optical element 106, causing the EMR beam 104 to converge to a focal point 108 (or "focusing region") as it propagates along an optical axis 110. According to some embodiments, the EMR beam 104 converges to the focal point 108 using a numerical aperture between 0.1 and 1.0 (e.g., 0.5).

[0041] The treatment system 100 can include a cooling element 150 that includes a first window 112, a chamber 114 configured to receive / contain a flow of a coolant 116 (e.g., a fluid coolant), and a second window 118. The cooling element can be located downstream of the optical element 106. The term "downstream" indicates that the EMR beam 104 first impinges on the optical element 106 and then impinges on the cooling element 150. In other words, the optical element 106 is located upstream of the cooling element 150.

[0042] The EMR beam 104 can be transmitted through a cooling element 150, which includes a first window 112, a chamber 114 configured to receive / contain a flow of a coolant 116 (e.g., a fluid coolant), and a second window 118. For example, the first window 112, the coolant 116, and the second window 118 can substantially transmit the EMR beam 104. According to some embodiments, the EMR beam can converge (e.g., be focused) as it passes through the first window 112, the chamber 114, the flow of the coolant 116, and the second window 118. The EMR beam 104 can reach the focal point 108 after propagating through a distal surface 120 of the second window 118. There is a working distance 122 between the focal point 108 and the distal surface 120 of the second window 118. According to some embodiments, the working distance 122 can have a value between 0.001 millimeters (mm) and 100 mm (e.g., 0.5 mm, 1.0 mm, and 10 mm).

[0043] According to some embodiments, the coolant flow source 124 can initiate a flow of coolant 116, which can be contained / received by the chamber 114 located between the first window 112 and the second window 118 (e.g., located between the distal surface of the first window 112 and the proximal surface of the second window 118). An exemplary coolant flow source is a compact cooler (product number UC160-190) from Steady State Cooling Systems of Wappingers Falls, New York. The UC160-190 is capable of generating a coolant flow 124 having a flow rate of 500 ml / min±50 ml / min at 9 psig, a maximum pressure of 30 psig, and a coolant temperature between 2°C and 45°C. The coolant can be generally transparent (e.g., greater than 50% transparent) at the wavelength of the EMR beam 104. For example, a mixture of propylene glycol and water is generally transparent over a wavelength range including the visible spectrum and 1064 nm.

[0044] According to some embodiments, the treatment system 100 further includes a controller 126. The controller can be configured to control the EMR source 102 and the coolant flow source 124, the transmission direction of the EMR beam 104, the position / motion of the optical element 106 (e.g., the path of the optical element 106 with respect to the cooling element 150), etc. According to some embodiments, the temperature of the coolant 116 is controlled to within a few degrees Celsius of a set point. Exemplary coolant temperature set points include temperatures less than -10°C, 0°C, 5°C, and temperatures of approximately 10°C. According to some embodiments, the controller 126 controls one or more parameters of the coolant flow source 124, including the coolant set point temperature and the coolant flow rate. According to some embodiments, the controller 126 controls one or more parameters of the EMR source 102, including: pulse duration, repetition rate, EMR interlock or gate signal, pulse energy, average power, etc.

[0045] According to some embodiments, the treatment system 100 is configured to generate a plasma within the tissue 101 at or near the location of the focal point 108. In some embodiments, the plasma can be generated by optical means such as photoionization. In order to generate a plasma via photoionization, a large energy intensity may be required (e.g., for EMR pulses with pulse durations in the nanosecond range). For example, the irradiance threshold for photoionization of water can be as high as 10 13 W / cm 2 (For example, in 10 5 W / cm 2 Up to 10 13 W / cm 2 In other embodiments, the plasma may be generated by thermionic emission of electrons. Thermionic generation of the plasma may occur in the presence of a chromophore (e.g., a material configured to absorb the EMR beam 104) located at or near the focal point 108 of the EMR beam 104. The high energy intensity at the focal point may result in ionization of the chromophore and selective thermal damage to the chromophore and, in some cases, to materials near the chromophore. For example, the irradiance threshold for thermionic ionization in an absorbing medium for an EMR pulse with a pulse duration in the nanosecond range may be as low as 10 9 W / cm 2 Although the selective properties of the converging EMR beam 104 and the focal point 108 prevent immediate heating of non-target tissue, block heating may still occur at many EMR locations above or near one or more focal points 108 locations.

[0046] According to some embodiments, the cooling element 150 can cool the tissue 101 while it is irradiated by the EMR beam 104. In some embodiments, a heat path can travel from the focal point 108 (e.g., parallel / colinear with the optical axis 110) and pass through the tissue 101, the outer surface of the tissue 101, the distal surface 120 of the second window 118, the second window 118, and finally to the coolant 116 flow. The heat path can be the shortest path from the focal point 108 away from the tissue 101 and to the distal surface 120 of the second window 118 (e.g., the shortest path through the tissue 101). For this reason, the bulk heat of the tissue 101 can be effectively transferred to the coolant 116 (e.g., from the location of the focal point 108). Since the coolant and the window are both transparent at the wavelength of the EMR beam, cooling can be performed simultaneously with the irradiation. Some treatments require that the location of the focal point 108 within the tissue be carefully controlled and varied from time to time. In these cases, it may be desirable to have the position of the distal surface 120 of the second window 118 relative to the focal point 108 known and / or controlled. For example, a sensor (e.g., an accelerometer, a position detector, etc.) may detect the position and / or movement of the second window 118 (or cooling element 150) and may communicate this information to the controller 126. This may allow the position and / or movement of the second window 118 (or cooling element 150) to be tracked.

[0047] Dermal melasma can be treated by selective hot ion plasma in the pigment of the dermis. To perform this treatment, it may be desirable to have the focal point 108 of the EMR beam 104 at or near (e.g., 2 times the Rayleigh range) the depth of the pigment in the dermis (e.g., 100 μm to 1 mm below the surface of the tissue 101). Referring now to Figure 2A-2B , showing a change 200 in depth of the position of the focus 108 . Figure 2A Schematically illustrates a change 200 in the depth of focus 108 according to some embodiments. Translating 210 the optical element 106 relative to the second window 118 along the optical axis 110 (e.g., the z-axis) produces a corresponding change 200 in the depth of focus 108. According to some embodiments, the optical translation 210 can be generated by a stage and controlled by a controller. An exemplary stage is the M3-FS Focus Module from NewScale Technologies of Victor, NY. In some versions, the controller 126 controls one or more parameters of the stage, including acceleration, velocity, and position.

[0048] According to some embodiments, the position of focal point 108 may be changed (eg, by changing 200 ) with a corresponding change in divergence 220 of diverging EMR beam 222 . Figure 2B, the depth can be changed 200 from a first focal position 224 to a second focal position 226. The first focal position 224 is caused by a wave front change introduced by the optical element 106 to a first EMR beam 228 having negligible divergence. The second focal position 226 is caused by the same optical element 106, but located at a different position than the first focal position 224 due to an increased divergence 220. According to some embodiments, the change in divergence 220 is provided by an adaptive optical element such as a zoom lens. An exemplary zoom lens is Optotune product number EL-10-42-OF from Optotune Switzerland AG. Due to the extreme lateral (e.g., x-axis and y-axis) selectivity (e.g., stenosis) of the focal point 108, it can be desirable to scan the focal point 108 over multiple locations in the tissue 101. In some embodiments, the controller 126 can control one or more parameters of the adaptive optical device (e.g., for changing the divergence of the EMR beam).

[0049] Reference now Figure 3 , schematically illustrates an embodiment of a system including a beam scanner 300. Scanning 301 of the optical / EMR beam results in a translation (or rotation) of the focus position over a scan width 302. The scan width 302 is the distance over which the focus position varies laterally (i.e., x-axis and / or y-axis). In some embodiments, the beam scanner 300 can scan (e.g., move) 301 the EMR focus, optics, and optical axis (or RMR beam). Figure 3A scan 301 is shown from a first EMR beam position 314, a first optics position 316, and a first focus position 318 (along an optical axis 320) to a second EMR beam position 304, a second optics position 306, and a second focus position 308 (along an optical axis 310). According to some embodiments, the EMR beam and the optical axis remain incident on the first window 112, the chamber 114, and the second window 118 over the entire scan width. In some embodiments, the depth of the focus within the tissue can be controlled. For example, it may be desirable that the direction or plane of the scan 301 be parallel to the distal surface 120 of the second window 118 to be within a known specification. As described above, this is because a change in the distance between the distal surface 120 of the optics and the second window along the optical axis results in a change in the working distance 122 and the depth of the focus within the tissue. According to some embodiments, the second window 118 is maintained parallel to the scanning motion within a specified angle (e.g., 10 mrad, 1 mrad, 0.5 mrad, or 0.1 mrad). Alternatively, in some embodiments, the variation of the working distance 122 over the scan width 302 can be limited to an acceptable range (e.g., the working distance 122 varies by 0.25 mm over a scan width of 10 mm). The beam scanner 310 can be controlled by a controller (e.g., the controller 126). In some embodiments, the controller can control one or more parameters of the beam scanner, including jump speed, acceleration, position, dwell time, etc.

[0050] Figures 4A-4D An exemplary cooling element 400 is schematically represented in the various views of FIG. Figure 4A A top isometric view of the cooling element 400 is illustrated (eg, the portion of the cooling element 400 facing the EMR source / facing away from the target tissue). Figure 4B A bottom isometric view of the cooling element 400 is shown (eg, the portion of the cooling element 400 facing the target tissue / away from the EMR source). Figure 4C A bottom view of the cooling element 400 is shown. Figure 4D The cooling element 400 is shown along Figure 4C The exemplary cooling element 400 includes a frame 402. Figure 4A and 4C, the frame 402 has three references 404. The references 404 correspond to the mounts on the energy-based device that can generate radiation, thereby allowing the cooling element 400 to be attached and replaced on the energy-based device in a removable manner. According to some embodiments, the references 404 can approximate one or more geometric forms, such as planes, lines, and points. According to some versions, the references 404 include a portion of a kinematic support (e.g., a Maxwellian support). The three references 404 of the exemplary cooling element 400 can be located in a plane. The exemplary cooling element 400 further includes a first window 406 sealed to the frame 402 by a first seal 408, and a second window 410 sealed to the frame 402 by a second seal 412. According to some embodiments, the first seal 408 and the second seal 412 include an adhesive. Examples of adhesives can include light-curing adhesives, silicones, and epoxies. According to other embodiments, the first seal 408 and / or the second seal 412 include a weld, a hard solder, a soft solder, and the edges of the corresponding first window 406 and / or the second window 410 can be metallized, sprayed or coated with a material (e.g., a metal) that allows such a seal. In addition, the second window 410 is attached to the frame 402 using one or more fasteners 414. Figure 4C and 4D As can be seen in the exemplary cooling element 400, the fastener 414 comprises a clamp secured in place by three machine screws. Additional examples of fasteners may include screws, clamps, snaps, retaining rings, tabs, or any combination thereof. Attaching the second window 410 to the frame allows the distal surface 416 of the second window 410 to be securely placed in contact with tissue without introducing additional stress to the second seal 412 that would cause the distal surface of the second window to bend or move.

[0051] As described above, changes in the distance between the distal surface 416 and the optical element 16 that focuses the EMR beam 104 have an effect on the working distance 122 of the beam and the position of the resulting focal point 108 within the tissue 101. According to some embodiments, the distal surface 416 of the second window 410 can be positioned (e.g., oriented, located, etc.) in a predetermined geometric form relative to the reference 404. For example, in some versions, the second window 410 is positioned parallel to the plane approximated by one or more references 404 to be within a desired tolerance (e.g., 0.5 mrad). In addition, the second window 410 can be positioned at a precise distance along the optical axis (e.g., z-axis) within a desired tolerance (e.g., 0.05 mm). In addition, according to some embodiments, both the first window 406 and the second window 410 can be positioned in parallel, and the preset distance between them can be within a desired tolerance (e.g., 0.5 mrad and 0.05 mm). In some embodiments, the first window 406 and the second window 410 can be arranged at an angle with respect to each other (e.g., at an angle less than 10 mrad). For various reasons, the distal surface 416 of the second window includes a non-planar shape (eg, convex or concave) in some embodiments. For example, a convexly shaped distal surface 416 may be advantageous for compressing tissue when placed in contact with tissue.

[0052] Figure 4D A chamber 418 within the cooling element 400 is depicted. The chamber 418 is bounded by the frame 402, the first window 406, and the second window 410. The chamber 418 can be sealed by the first seal 408 and the second seal 412. The chamber 418 is configured to contain a coolant. According to some embodiments, a coolant flow is supplied to the chamber 418 through one or more ports 420 in fluid communication with the chamber 418. According to some embodiments, the port 420 can provide a coolant flow from a coolant flow source in fluid communication with the port 420. In some embodiments, the coolant flow source can be in fluid communication with the port 420 using one or more adapters 422. Figure 4A and 4B A coolant supply fitting 422a and a coolant return fitting 422b are illustrated for supplying and returning coolant to and from the chamber 418 .

[0053] According to some embodiments, the second window includes a material with high heat dissipation (e.g., quartz, sapphire, diamond, etc.). Higher heat dissipation can allow more heat to be transferred from the tissue surface to the coolant flow. Similarly, according to some embodiments, the first window 406 includes a material with lower heat dissipation (e.g., glass or polymer). An embodiment having a first window 406 with a lower heat dissipation material can transfer less heat to the coolant flow through the first window. As a result, condensation can occur more slowly than a version in which the first window 406 includes a high heat dissipation material. In addition, in some embodiments, the thickness of the first window (e.g., 1 mm) is greater than the thickness of the second window (e.g., 0.5 mm), which allows thermal energy to be transferred more freely across the second window. According to some versions, a non-condensing gas such as clean dry air, nitrogen, carbon dioxide or argon can be blown to the first window to further prevent condensation.

[0054] Reference now Figure 5 , depicts a flow chart describing a method 500 for irradiating and cooling tissue according to some embodiments. At 502, an electromagnetic radiation (EMR) beam is generated using an EMR source. At 504, a wavefront variation is introduced into the EMR beam, which causes the EMR beam to converge as it propagates along an optical axis. At 506, the converged EMR beam is transmitted through a first window, a coolant adjacent to the first window, and a second window 510 adjacent to the coolant. Finally, the converged EMR beam is directed to be incident on a surface region of tissue 512. At the same time, heat is transferred 514 from the surface region of the tissue to the coolant through the second window.

[0055] According to some embodiments of method 500, the converging EMR beam ultimately reaches a focus within the tissue at a depth below the surface area of ​​the tissue. In another version, the depth of the focus varies over time. As described above, varying the depth of the focus within the tissue allows for treatments that require energy delivery over a range of depths, such as in the treatment of dermal melasma. In some versions, the depth varies over a range of 0.001 mm to 10 mm. In some versions, the EMR beam at the focus has an energy intensity sufficient to cause thermal ionization in the pigmented tissue (e.g., greater than about 10 J / cm for a pulse duration of 100 nanoseconds and a wavelength of 1064 nm). 2 energy intensity).

[0056] According to some embodiments, method 500 further includes scanning the converged EMR beam along one or more axes over a scan width, and causing the EMR beam to be directed toward a second surface region of the tissue 512. Typically, the EMR beam is a pulsed energy source, and each pulse causes the EMR beam to be directed toward a new surface region as it is scanned. In some versions, beam scanning is performed along one or more axes generally parallel to a distal surface of the second window (along an xy plane parallel to the second / first window) so that the depth of focus does not vary by more than a desired tolerance (e.g., 0.25 mm or 0.05 mm) over the scan width.

[0057] According to some embodiments, at 502, an EMR beam is generated at an average power of at least up to 1 W, 5 W, 10 W, or 30 W. According to some embodiments, the EMR beam is generated at a wavelength in a range between 400 nm and 4000 nm. According to some embodiments, a wavefront variation 504 is introduced to the EMR beam 5 to cause the EMR beam to converge at a rate according to a numerical aperture (NA) of at least 0.3.

[0058] According to some embodiments, a table is provided below to summarize exemplary parameters and parameter ranges.

[0059]

[0060]

[0061]

[0062] Properties of therapeutic radiation

[0063] Figure 6It is a schematic diagram of a diagram of a laser beam focused into the colored area of ​​the dermis layer in the skin tissue. The skin tissue includes a skin surface 600 and an upper epidermis layer 610 or epidermis, which can be, for example, about 30-120 μm thick in the face area. In other parts of the body, the dermis can be slightly thicker. For example, the thickness range of the epidermis can generally be from about 30 μm (for example, on the eyelids) to about 1500 μm (for example, on the palm of the hand or the sole of the foot). In certain skin conditions such as psoriasis, such an epidermis may be thinner or thicker than the above examples. The lower dermis layer 620 or dermis extends from below the epidermis 610 to a deeper subcutaneous fat layer (not shown). The skin showing depth or dermal melasma can include a colony of pigmented cells or regions 630 containing excessive melanin. Electromagnetic radiation (EMR) 650 (e.g., a laser beam) can be focused into one or more focal regions 660, which can be located within the dermis 620 or the epidermis 610. The EMR 650 can be provided at one or more appropriate wavelengths that can be absorbed by melanin. The EMR wavelength(s) can be selected based on one or more criteria described below.

[0064] Determination of a desired wavelength for treatment of certain skin conditions, such as pigmented conditions and non-pigmented conditions, may depend, for example, on the wavelength-dependent absorption coefficients of various competing chromophores in the skin (eg, chromophores, hemoglobin, tattoo ink, etc.). Fig. 7A is an exemplary absorption spectrum of melanin. It is observed that the absorption of EMR by melanin reaches a peak at a wavelength of about 350 nm and then decreases as the wavelength increases. Although the absorption of EMR by melanin promotes heating and / or destruction of the area containing melanin, a very high absorption rate of melanin results in a high absorption of the pigment in the epidermis 610 and a reduction in the EMR that penetrates into the dermis 620 or epidermis 610. Fig. 7A As shown in , melanin absorption at EMR wavelengths less than about 500 nm is relatively high, and thus wavelengths less than about 500 nm may not be suitable for sufficient penetration into the dermis 620 to heat and damage or destroy the pigmented regions 630 therein. This increased absorption at smaller wavelengths can result in undesirable damage to the epidermis 610 and the upper (outer surface) portions of the dermis 620, as relatively little unabsorbed EMR passes through the tissue into the deeper portions of the dermis 620.

[0065] Figure 7B is an exemplary absorption spectrum of oxygenated or deoxygenated hemoglobin. Hemoglobin is present in the blood vessels of skin tissue and can be oxygenated (HbO 2 ) or deoxygenated (Hb). Each form of hemoglobin can exhibit slightly different EMR absorption properties. Figure 7B As shown in2 The exemplary absorption spectra of both indicate Hb and HbO 2 Both have high absorption coefficients at EMR wavelengths less than about 600 nm, with the absorption rate decreasing significantly at higher wavelengths. Hemoglobin (Hb and / or HbO 2 ) The vigorous absorption of EMR directed into the skin tissue can cause heating of the hemoglobin-containing blood vessels, causing undesirable damage to these vascular tissues and making less EMR available for absorption by melanin.

[0066] Selection of an appropriate wavelength for EMR may also depend on the wavelength-dependent heat dissipation profile of the tissue with which the EMR interacts. Figure 8 Shown are plots of the absorption coefficients of melanin and venous blood versus wavelength. Figure 8 Also illustrated is a plot of the scattering coefficient of light in the skin compared to wavelength. Absorption in melanin decreases monotonically with wavelength. If melanin is the target of treatment for pigmentary conditions, wavelengths with high absorption in melanin are desirable. This would suggest that the shorter the wavelength of light, the more effective the treatment. However, absorption by blood increases at wavelengths shorter than 800nm, thereby increasing the risk of inadvertently targeting blood vessels. In addition, since the intended target may be below the surface of the skin, the role of scattering by the skin (e.g., dermis) can be important. Scattering reduces the amount of light that reaches the intended target. The scattering coefficient decreases monotonically with increasing wavelength. Therefore, while shorter wavelengths can contribute to absorption by melanin, longer wavelengths can contribute to deeper penetration due to reduced scattering. Similarly, since blood has lower absorption at longer wavelengths, longer wavelengths are better for avoiding blood vessels.

[0067] In view of the above considerations, wavelengths ranging from about 300nm to about 3000nm, and more specifically about 800nm ​​to about 1064nm can be used to selectively target certain structures (e.g., melanin) in the dermis. In particular, wavelengths of 800nm ​​and about 1064nm can be useful for such treatments. The reason why the 800nm ​​wavelength is attractive is that laser diodes at this wavelength are not too expensive and easy to obtain. However, 1064nm is particularly useful for targeting deeper lesions due to lower scattering at this wavelength. The wavelength of 1064nm is also more suitable for darker skin types containing a large amount of epidermal melanin. In such individuals, the higher absorption of melanin in the epidermis for lower wavelength EMR (e.g., about 800nm) increases the chance of thermal damage to the skin. Therefore, for certain treatments for some individuals, 1064nm may be a more appropriate wavelength for therapeutic radiation.

[0068] Various laser sources can be used for the generation of EMR. For example, laser sources containing neodymium (Nd) are easily accessible, which provide EMR at 1064nm. These laser sources can be operated in a pulse mode with a repetition rate in the range of about 1Hz to 100KHz. Q-switched Nd laser sources can provide laser pulses with a pulse duration less than 1 nanosecond. Other Nd laser sources can provide pulses with a pulse duration exceeding 1 millisecond. An exemplary laser source providing EMR at a wavelength of 1064nm is a 20W NuQ fiber laser from Nufern in East Granby, Connecticut, USA. The 20W NuQ fiber laser provides pulses with a pulse duration of about 100ns with a repetition rate in the range between about 20KHz and about 100KHz. Another laser source is the Nd:YAG Q-smart 850 from Quantel in Les Ulis, France. The Q-smart 850 provides pulses with pulse energies up to about 850 mJ and pulse durations of about 6 ns at repetition rates up to about 10 Hz.

[0069] The system described herein can be configured to focus the EMR in a highly convergent beam. For example, the system can include a focusing or converging lens device having a numerical aperture (NA) selected from about 0.3 to 0.9 (e.g., between about 0.4 and 0.9). The large convergence angle corresponding to the EMR can provide high flux and intensity in the focal region of the lens (which can be located in the dermis), while the energy flux in the overlying tissue above the focal region is lower. Such a focusing geometry can help reduce unwanted heating and thermal damage in the overlying tissue above the pigmented dermal area. The exemplary optical device can further include a collimating lens device, which is configured to direct the EMR from the emitting device onto the focusing lens device.

[0070] The exemplary phototherapy system can be configured to focus EMR to a focal region having a width or spot size of less than about 200 μm, such as less than about 100 μm, or even less than about 50 μm, such as as small as about 1 μm. For example, the spot size can have a range from about 1 μm to about 50 μm, from about 50 μm to about 100 μm, and from about 100 μm to about 200 μm. The spot size of the focal region can be determined, for example, in air. Such a spot size can be selected to balance between being small enough to provide a high EMR flux or intensity in the focal region (to effectively irradiate pigmented structures in the dermis) and being large enough to facilitate irradiation of large areas / volumes of skin tissue within a reasonable treatment time.

[0071] The exemplary optical device can also be configured to direct the focal area of ​​the EMR to a position within the dermis tissue at a depth below the skin surface, such as a range from about 30 μm to about 2000 μm, for example, between about 150 μm and about 500 μm. Such an exemplary depth range can correspond to the depth of the typical observed pigmented area in the skin showing dermal melasma or other targets of interest. The focal depth can correspond to the distance from the lower surface of the device configured to contact the skin surface to the position of the focal area. In addition, some embodiments can be configured to treat targets within the epidermis. For example, an optical device can be configured to direct the focal area of ​​the EMR to a position within the epidermis tissue, such as within a range from about 5 μm to about 2000 μm below the skin surface. Yet other embodiments can be configured to treat target depths in the dermis. For example, tattoo artists typically calibrate their tattoo guns to penetrate the skin to a depth from about 1 mm to about 2 mm from the skin surface. Thus, in some embodiments, an optical device can be configured to direct a focal region of EMR to a location within dermal tissue ranging from approximately 0.4 mm to 2 mm below the surface of the skin.

[0072] Example

[0073] Fig. 9A The diagram depicts a plurality of exemplary cooling elements (e.g., FIG. 9B to FIG. 9D Multiple plots of the cooling performance of a cooling element in FIG. Fig. 9A The data shown in 900 was collected during experiments performed using cooling elements 920, 930, and 940. Graph 900 has temperature shown in degrees Celsius along a vertical axis 910 and time shown in minutes and seconds along a horizontal axis 920.

[0074] Each cooling element is placed in the test card block, and a thermocouple is placed in the middle of the first surface of the cooling element. Thermal glue is used to ensure thermal conduction between the first surface of the cooling element and the thermocouple. The cooling element is placed in a manner that the first surface is in contact with a dry bath. The dry bath is set to 37°C and each cooling element is allowed to approach thermal equilibrium with the dry bath. Finally, a cold fluid at 5°C is provided to the cooling element, and the thermocouple captures its temperature measurement value when the first surface of the window is cooled.

[0075] FIG. 9B to FIG. 9D Schematic diagrams of exemplary cooling elements tested as part of the experiments discussed above are illustrated. The exemplary embodiments of the cooling elements are a first single window type cooling element 920, a second single window type cooling element 930, and a dual window type cooling element 940. Fig. 9BA single window type cooling element 920 is illustrated, which includes a single sapphire window 922 in contact with an aluminum heat exchanger 924 in which a coolant 926 flows (e.g., along the edge of the sapphire window). Heat flows from a dry bath 928 to the middle of a first surface of the sapphire window 922 (e.g., a surface adjacent to the dry bath 928), horizontally through the sapphire window 922 to the edge of the sapphire window 922, past the aluminum heat exchanger 924 and into the coolant 926. The temperature of the first surface of the window 922 is measured by a thermocouple 929.

[0076] Fig. 9C A single window type cooling element 930 is illustrated that includes a single sapphire window 932 sealed to a manifold 934 in which a coolant 936 flows. The single window type cooling element 930 is configured to allow the coolant 936 to directly contact the single sapphire window 932 around the edge of the window 932. Heat flows from the dry bath 938 to the center of the first surface of the window 932 (e.g., the surface adjacent to the dry bath 938), the edge of the window 932, and directly into the coolant 936. The temperature of the first surface of the window 932 is measured by a thermocouple 939.

[0077] Fig.9D A dual window type cooling element 940 is illustrated, which includes a first window 942, a second window 943, a frame 944, and a coolant 946 flowing between the first window 942 and the second window 943. Heat flows from a dry bath 948 to the center of a first surface of the first window 942 (e.g., a surface adjacent to the dry bath 948), vertically passes through the first window 942, and enters the coolant 946. The temperature of the first surface of the window 942 is measured by a thermocouple 949.

[0078] Back to Fig. 9A, showing cooling data for cooling elements 920, 930, and 940. A first set of plots 920A to 920D represent cooling data for a first single window type cooling element 920, a first set of plots 930A to 930B represent cooling data for a second single window type cooling element 930, and a third plot 940A represents cooling data for a dual window type cooling element 940. The plots indicate that cooling of the second single window type cooling element 930 is improved over the first single window type assembly 920. However, the dual window type cooling element 940 shows a substantial improvement over the first single window type assembly and the second single window type assembly. The data for the dual window type cooling element 940 shows cooling close to a steady state temperature of about 13.4°C. The lowest window surface temperature measured for the second single window type cooling element 930 is close to a steady state temperature of about 25.9°C. The dual window type cooling element 940 can cool to a temperature of 12.5°C, which can be cooler than the best performing single window type assembly. Graph 900 also shows that cooling occurs faster with the dual window type cooling element 940. Based on this data, the thermal time constant (e.g., time for the window to cool to about 63.2% of the initial temperature) for the first window type assembly and the second window type assembly is estimated to be about 4 seconds. The thermal time constant for the dual window type assembly is estimated to be about 2 seconds, or half that of the single window type assembly.

[0079] The systems described herein can be used to perform methods for treating various skin conditions, such as for cosmetic purposes. It is understood that, although such methods can be performed by a physician, non-physicians, such as beauticians, and other appropriately trained personnel can also use the systems described herein to treat various skin conditions with or without physician supervision.

[0080] Those skilled in the art will appreciate further features and advantages of the present invention based on the embodiments described above. Therefore, except as indicated by the appended claims, the present invention is not limited by the content specifically shown and described. The publications and documents cited herein are expressly incorporated herein in their entirety by reference.

[0081] The subject matter described herein can be implemented in digital electronic circuits, or in computer software, firmware or hardware (including the structural means disclosed in the specification and their structural equivalents), or in a combination thereof. The subject matter described herein can be implemented as one or more computer program products, such as one or more computer programs embodied in a tangible manner in an information carrier (e.g., in a machine-readable storage device) or embodied in a propagation signal, so that they can be executed or controlled by a data processing device (e.g., a programmable processor, a computer, a plurality of computers). Computer programs (also referred to as programs, software, software applications or codes) can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as independent programs or as modules, components, subroutines or other units suitable for use in a computing environment. A computer program does not necessarily correspond to a file. A program can be stored in a portion of a file that stores other programs or data, in a single file dedicated to the program in question, or in multiple collaborative files (e.g., in a file storing one or more modules, subroutines or code portions). A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[0082] The processes and logic flows described in this specification, including the method steps of the subject matter described herein, can be performed by one or more programmable processors that execute one or more computer programs to perform the functions of the subject matter described herein by operating on input data and generating output. The processes and logic flows can also be performed by special purpose logic circuits such as FPGAs (field programmable gate arrays) or ASICs (application specific integrated circuits), and the apparatus of the subject matter described herein can also be implemented as such special purpose logic circuits.

[0083] Processors suitable for executing computer programs include, for example, general or special purpose microprocessors, and any one or more processors of any type of digital computer. Typically, the processor will receive instructions and data from a read-only memory or a random access memory or both. The essential components of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more large storage devices (such as magnetic disks, magnetic optical disks, or optical disks) for storing data, or operatively coupled to receive or transmit data from or to it (or both). Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, such as semiconductor memory devices (such as EPROM, EEPROM, and flash memory devices); magnetic disks (such as internal hard disks or removable disks); magnetic optical disks; and optical disks (such as CD and DVD disks). The processor and memory can be supplemented with or incorporated into a dedicated logic circuit.

[0084] To provide interaction with a user, the subject matter described herein can be implemented on a computer having a display device such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor for displaying information to the user, and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user. For example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback), and the input from the user can be received in any form, including sound, voice, or tactile input.

[0085] The technology described herein can be implemented using one or more modules. As used herein, the term "module" refers to computer software, firmware, hardware, and / or various combinations thereof. However, at the lowest level, a module is not interpreted as software that is not implemented on hardware, firmware, or recorded on a recordable storage medium that is readable by a non-transient processor (i.e., a module is not software itself). In fact, a "module" is interpreted as always including at least some physical, non-transient hardware, such as a part of a processor or a computer. Two different modules can share the same physical hardware (for example, two different modules can use the same processor and network interface). The modules described herein can be combined, integrated, separated and / or copied to support various applications. Moreover, the function described herein as being implemented at a specific module can be implemented at one or more other modules, and / or implemented by one or more other devices, to replace the implementation of the function at the specific module or in addition thereto. Further, a module can be implemented across multiple devices and / or other components that are locally or far away from each other. In addition, a module can be removed from one device and added to another device, and / or can be included in two devices.

[0086] The subject matter described herein can be implemented in a computing system that includes a back-end component (e.g., a data server), a middleware component (e.g., an application server), or a front-end component (e.g., a client computer with a graphical user interface or a web browser through which a user can interact with an implementation of the subject matter described herein), or any combination of such back-end, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication, such as a communication network. Examples of communication networks include local area networks (LANs) and wide area networks (WANs) such as the Internet.

[0087] Approximate language as used herein throughout the specification and claims may be applied to modify any quantitative representation that is permitted to vary without causing a change in the basic function involved. Thus, a numerical value modified by one or more terms such as "approximately" or "substantially" is not limited to the exact numerical value specified. In at least some instances, the approximate language may correspond to the precision of the instrument used to measure the numerical value. Herein and throughout the specification and claims, range limitations may be combined and / or interchanged, and unless the context or language indicates otherwise, such a range is identified and includes all subranges contained therein.

Claims

1. A system comprising: an optical element configured to receive electromagnetic radiation (EMR) and focus the EMR along an optical axis to a focal region in a target tissue; a controller configured to direct the optical element along a first scanning path, wherein movement of the optical element along the first scanning path is configured to cause the focal region to traverse a treatment path in the target tissue; a cooling element downstream of the optical element and configured to be removably attached to the system via three or more fiducials and to receive the focused EMR, the cooling element comprising: a first window comprising a first proximal surface and a first distal surface; a second window downstream of the first window, the second window comprising a second proximal surface and a second distal surface, wherein the second window is configured to contact the target tissue or tissue adjacent to the target tissue via the second distal surface, and wherein the first scanning path is parallel to the second distal surface; A coolant lumen is located between the first distal surface of the first window and the second proximal surface of the second window and is configured to receive a coolant.

2. The system of claim 1 , wherein the controller is configured to change a first distance along the optical axis between the focal region and the second distal surface of the second window by changing a second distance along the optical axis between the optical element and the second distal surface of the second window.

3. The system of claim 2, wherein the first distance varies between a first predetermined value and a second predetermined value as the focal region traverses the treatment path in the target tissue.

4. The system of claim 3, wherein the difference between the first predetermined value and the second predetermined value is less than 0.25 mm.

5. The system of claim 3, wherein the first predetermined value is 0.001 mm, and the second predetermined value is 10 mm.

6. The system of claim 1, wherein the controller is configured to change a first distance along the optical axis between the focal region and the second distal surface of the second window by changing a divergence associated with the EMR. 7 . The system of claim 1 , further comprising a scanner, wherein the scanner is configured to receive a control signal from the controller and to move the optical element along the first scanning path perpendicular to the optical axis based on the control signal.

8. The system of claim 1, wherein the controller is configured to vary an intensity of the EMR.

9. The system of claim 1, wherein the controller is configured to vary a flow rate of the coolant in the coolant cavity.

10. The system of claim 1, wherein the optical element has a numerical aperture (NA) in the range of 0.1 to 1.

0.

11. The system of claim 1, wherein the EMR has an average power in the range of 1 W to 100 W.

12. The system of claim 1, wherein the EMR comprises a pulsed laser beam having a wavelength in the range of 400 nm to 4000 nm.

13. The system of claim 1, wherein the EMR is configured to generate a thermal ionic plasma in the focusing region.

14. The cooling element of claim 1, further comprising a gas source configured to direct a gas to the first window, the gas configured to prevent condensation on the first window.

15. The system of claim 1, wherein the first window has a first heat dissipation property and the second window has a second heat dissipation property, the second heat dissipation property being greater than the first heat dissipation property.

16. The system of claim 1, wherein the first window and the second window are sealed to the frame of the cooling element via a first seal and a second seal, respectively, wherein the first seal and the second seal comprise one or more of a weld, a soft solder, a hard solder.

17. The system of claim 1, wherein the optical element is configured to change a position of the focal region along the optical axis by traveling along the optical axis.

18. A cooling element comprising: a framework comprising one or more datums, the one or more datums defining a datum plane; a first window, the first window comprising a first proximal surface and a first distal surface, the first window being sealed to the frame; a second window sealed to the frame and arranged at an angle of less than 10 mrad relative to the reference plane, the second window comprising a second proximal surface and a second distal surface, wherein the second window is configured to contact a target tissue or tissue adjacent to the target tissue via the second distal surface; and a coolant lumen located between the first distal surface of the first window and the second proximal surface of the second window and configured to receive a coolant, The first window, the second window, and the coolant chamber are configured to receive electromagnetic radiation (EMR) and transmit a portion of the received EMR to the target tissue.

19. The cooling element of claim 18, wherein the coolant cavity comprises a port configured to direct coolant from a coolant flow source to the coolant cavity.

20. The cooling element of claim 18, wherein the first window is sealed to the frame via a first seal and the second window is sealed to the frame via a second seal.

21. The cooling element of claim 20, wherein the first seal comprises one or more of an adhesive, a weld, a soft solder, a hard solder, a polymer, and an elastomer.

22. The cooling element of claim 18, wherein the first window has a first heat dissipation property and the second window has a second heat dissipation property, the second heat dissipation property being greater than or equal to the first heat dissipation property.

23. The cooling element of claim 18, wherein the first window has a first thickness and the second window has a second thickness, the second thickness being less than the first thickness.

24. The cooling element of claim 18, wherein the second distal surface of the second window has a shape comprising one or more of flat, convex, and concave.

25. The cooling element of claim 18, further comprising a fastener, wherein the fastener is configured to attach the second window to the frame.

26. The cooling element of claim 25, wherein the fastener comprises at least one of a screw, a clamp, a snap, a retaining ring, and a tab.

27. The cooling element of claim 18, wherein the second window comprises at least one of: sapphire, quartz, and diamond.

28. The cooling element of claim 18, wherein the first window is arranged at a second angle with respect to the second window, the second angle being less than 10 mrad.

29. The cooling element of claim 18, wherein the coolant comprises a mixture of propylene glycol and water.

30. The cooling element of claim 18, wherein the EMR has a wavelength in the range of 400 nm to 4000 nm.

31. The cooling element of claim 18, wherein the EMR exhibits convergence with a numerical aperture greater than or equal to 0.3.

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