Feedback Detection for a Therapeutic Device

Abstract

According to some embodiments, a system for fractionating and treating tissue includes an electromagnetic radiation (EMR) source configured to generate an EMR beam having a transverse ring energy profile, an optical system configured to focus the EMR beam to a focal region located within the tissue, and a window assembly located in the beam downstream from the optical system configured to cool the tissue when placed in contact with an outer surface of the tissue.

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 934,583, filed on November 13, 2019, entitled "Electromagnetic Radiation-Based Treatment Apparatus and Method", which is hereby incorporated by reference in its entirety.

Background Art

[0002] Currently, many energy-based devices can be used for fractionated treatment of the dermis. These methods include ablative lasers, non-ablative lasers, micro-needling, and RF energy treatment. Generally, such currently available fractionated energy-based treatments require damage to the outer portion of the skin (e.g., the epidermis) during treatment. In many cases, when the epidermis is damaged, the skin can become inflamed, damaged, or unhealthy immediately after treatment. Also, severe damage to the epidermis can result in one or more infections and may require additional treatment. Such an undesirable appearance results in a post-treatment downtime that lasts until the epidermis heals, which can take several days to several weeks depending on the treatment parameters used (e.g., ablative vs. non-ablative). Many patients are unable to return to their normal lives until the post-treatment downtime has ended. Therefore, in order to minimize the post-treatment downtime, it is desirable to have available a fractionated treatment system and method that can reliably affect the dermis while minimizing damage to the epidermis.

Summary of the Invention

Means for Solving the Problems

[0003] Skin rejuvenation is often performed by fractional treatment. Fractional or fractionated energy-based treatments refer to treatments where only a partial area of tissue is exposed to energy. For example, in fractional skin treatment, a laser beam can treat 25% of an area of skin and leave the remaining 75% of the skin in that area untreated. Energy-based skin rejuvenation involves creating controlled small injuries within the collagen network. These small injuries trigger the wound healing process where new collagen is formed. The newly formed collagen tightens the skin, making it look younger. Many fractional skin rejuvenation treatment systems operate by targeting water as the chromophore to achieve photothermolysis.

[0004] Fractional treatments can generally be divided into two categories: ablation and non-ablation. Ablative treatments remove tissue, cause thermal damage within the dermis, and result in micro-injuries on the surface. Non-ablation treatments usually do not induce tissue removal but instead induce only thermal destruction. The advantage of non-ablation fractional treatments over ablation fractional treatments is that they shorten the downtime.

[0005] In energy-based fractional treatment of tissue, generally a large amount of energy must be delivered and absorbed by a selected portion of the tissue to cause the desired destruction or injury. Since such destruction or injury is repeated in tissue regions, small areas of destroyed tissue (e.g., 0.1 - 10 mm in diameter) are combined with non-damaged tissue. The small areas of damaged tissue are replaced by new tissue during the healing process after treatment. Inducing injury within the dermis of the skin while minimizing injury to the overlying epidermal layer presents various technical challenges, some of which are listed below.

[0006] First, there are no known chromophores in the dermis of the tissue that do not exist in the epidermal layer of the tissue. This means that radiation selected to be absorbed in the dermis is also absorbed in the epidermal layer.

[0007] Second, since EMR is absorbed equally by the epidermal and dermal layers of the skin, it is necessary to supply a higher energy density to the dermal layer than to the epidermis. To achieve this, the EMR profile needs to be varied such that the focal region of the EMR beam (i.e., the region of maximum energy density) is located within the dermis and only the regions where the EMR beam is out of focus (i.e., the regions of minimum energy density) are subordinate to the epidermal layer of the skin.

[0008] Third, skin tissue is a turbid medium, which means that the radiation propagating through the skin is scattered. The scattering of radiation within the skin tissue makes it even more difficult to form a focal region (region of maximum energy density) at any depth within the tissue, complicating the first and second problems described above.

[0009] Fourth, the focal region (or region of maximum energy density) needs to be accurately positioned at a depth within the dermal layer of the skin. This ensures that the region of maximum energy density is located within the dermis and not within the epidermis in order to prevent unwanted damage to the epidermis.

[0010] Fifth, the EMR beam is transmitted from outside the tissue, and thus the epidermis experiences minimal irradiation and mild thermal heating (i.e., less than the dermis). In response to this fifth problem, it is necessary to actively cool the epidermal layer directly above the dermal layer during treatment to prevent thermal damage to the epidermis.

[0011] Therefore, there is a need for a fractional treatment system and method that solves all of the above problems while providing a therapeutic disruption that is partitioned to the dermal layer of the skin tissue while minimizing damage to the upper epidermal layer.

[0012] According to some embodiments, a system for dividing and treating tissue includes an electromagnetic radiation (EMR) source configured to generate an EMR beam having a lateral ring energy profile, an optic configured to focus the EMR beam into a focal region located within the tissue, and a window assembly located downstream of the optic and configured to cool the tissue when disposed in contact with the outer surface of the tissue. The window assembly includes a first window, a second window separated from the first window, and a coolant chamber located between the first window and the second window, the coolant chamber being configured to contain a coolant that is substantially non-absorbent to the EMR beam.

[0013] In some embodiments of the system, the EMR beam has a wavelength in the range between about 1000 nm and 4000 nm.

[0014] In some embodiments of the system, the coolant includes at least one of a dielectric fluid, a fluorocarbon-based fluid, water, antifreeze, ethylene glycol, and propylene glycol.

[0015] In some embodiments of the system, the optic is further configured to focus the EMR beam with a numerical aperture (NA) of at least about 0.2.

[0016] In some embodiments of the system, the system also includes an optical clearing medium located between the window assembly and the tissue. Optionally, the optical clearing medium includes at least one of glycerin, polyethylene glycol, and phosphate-buffered saline.

[0017] In some embodiments of the system, the EMR source includes a beam shaper configured to shape a lateral ring energy profile. In some variations of the system, the beam shaper includes an axicon.

[0018] In some embodiments of the system, the system further includes a controller. Optionally, the controller is configured to control the EMR source to ensure that the window assembly cools the tissue to a predetermined temperature before generating the EMR beam. Optionally, the controller is configured to control the EMR source to ensure that the window assembly cools the tissue for a predetermined period before generating the EMR beam.

[0019] According to some embodiments, a method for partially treating tissue includes cooling the tissue using a window assembly that contacts an outer surface of the tissue, generating an EMR beam having a lateral ring energy profile using an electromagnetic radiation (EMR) source, and focusing the EMR beam into a focal region located within the tissue using an optical system. Optionally, the window assembly includes a first window, a second window separated from the first window, and a coolant chamber located between the first window and the second window, and the coolant chamber is configured to contain a coolant that is substantially non-absorbent of the EMR beam.

[0020] In some embodiments of the method, the EMR beam has a wavelength in the range between about 1000 nm and 4000 nm.

[0021] In some embodiments of the method, the coolant includes at least one of a dielectric fluid, a fluorocarbon-based fluid, water, ethylene glycol, and propylene glycol.

[0022] In some embodiments of the method, focusing the EMR beam is performed with a numerical aperture (NA) of at least about 0.2.

[0023] In some embodiments of the method, the method further includes introducing an optical tissue clearing medium between the window assembly and the tissue. Optionally, the optical tissue clearing medium includes at least one of glycerin, polyethylene glycol, and phosphate buffered saline.

[0024] In some embodiments of the method, the EMR source further includes a beam shaper configured to shape a lateral ring energy profile. In some variations of the method, the beam shaper includes an axicon.

[0025] In some embodiments of the method, the method further includes using a controller to control the EMR source to ensure that the window assembly cools the tissue to a predetermined temperature before generating the EMR beam.

[0026] In some embodiments of the method, the method further includes using a controller to control the EMR source to ensure that the window assembly cools the tissue for a predetermined period before generating the EMR beam.

[0027] According to some embodiments, a system for partially treating tissue includes an electromagnetic radiation (EMR) source configured to generate an EMR beam having a wavelength in the range of from about 1400 nm to 3400 nm, a beam shaper configured to shape the EMR beam into a transverse ring energy profile, the beam shaper including an axicon, an optical system configured to focus the EMR beam into a focal region located within the tissue with an aperture number (NA) of at least about 0.2, and a window assembly located downstream of the beam from the optical system configured to cool the tissue when disposed in contact with an outer surface of the tissue, the window assembly including a first window, a second window separated from the first window, and a coolant chamber located between the first window and the second window, the coolant chamber configured to contain a coolant including a substantially non-absorbing fluorocarbon-based fluid of the EMR beam, and a controller configured to control the EMR source to ensure that the window assembly cools the tissue by at least one of a predetermined temperature and a predetermined time before generating the EMR beam.

[0028] According to some embodiments, a system for partially treating tissue includes an electromagnetic radiation (EMR) source configured to generate an EMR beam having a wavelength, a collimator configured to collimate the EMR beam in width, a beam shaper including a first axicon and a second axicon configured to shape the collimated EMR beam into a transverse ring energy profile, the first axicon and the second axicon being separated by a distance along an optical axis selected to affect a desired inner diameter of the transverse ring energy profile and the width of the collimated EMR beam being selected to affect a desired thickness of the transverse energy profile, and an optical system configured to focus the EMR beam into a focal region within the tissue to affect the tissue having the focal region.

[0029] According to some embodiments, the system includes an EMR source configured to generate an EMR beam having a lateral ring-shaped energy profile and a wavelength in the range of from about 1200 nm to about 12000 nm, an optical system configured to focus the EMR beam onto a focal region located within the tissue, a beam scanning system configured to scan the focal region within the tissue, and a window assembly located downstream of the beam from the optical system configured to cool the tissue when the EMR beam is transmitted and placed in contact with the outer surface of the tissue, the window assembly including a first window, a second window separated from the first window, and a coolant chamber located between the first window and the second window, the coolant chamber configured to contain a coolant including a fluorocarbon-based fluid that is substantially non-absorbent of the EMR beam, and a controller configured to control the EMR source to generate the EMR beam in a plurality of pulses, at least one of the plurality of pulses having a pulse duration not less than about 100 microseconds.

[0030] In some embodiments of the system, at least one of the plurality of pulses has a pulse energy not greater than about 100 mJ.

[0031] In some embodiments of the system, the system further includes a chiller configured to cool the coolant to a temperature within the range of from about -20°C to about 20°C.

[0032] In some embodiments of the system, the optical system is further configured to focus the EMR beam with an aperture number (NA) of at least about 0.2.

[0033] In some embodiments of the system, the system further includes an optical tissue clearing medium located between the window assembly and the tissue, the optical tissue clearing medium including at least one of glycerin, polyethylene glycol, and phosphate buffered saline.

[0034] In some embodiments of the system, the EMR source further includes a beam shaper configured to shape a lateral ring-shaped energy profile. In some variations of the system, the beam shaper includes an axicon.

[0035] In some embodiments of the system, the controller is configured to control the EMR source to ensure that the window assembly cools the tissue to a predetermined temperature before generating the EMR beam.

[0036] In some embodiments of the system, the controller is configured to control the EMR source to ensure that the window assembly cools the tissue for a predetermined period before generating the EMR beam.

[0037] In some embodiments of the system, at least one of the EMR source, the optical system, and the beam scanning system is configured to control one or more parameters of the EMR beam, including one or more of the inner diameter of the ring-shaped energy profile, the outer diameter of the ring-shaped energy profile, the thickness of the ring-shaped energy profile, and the depth of the focal region within the tissue.

[0038] According to some embodiments, the method includes cooling the tissue using a window assembly that contacts the outer surface of the tissue; generating an EMR beam having a lateral ring-shaped energy profile and a wavelength in the range of about 1200 nm to 12000 nm using an EMR source; focusing the EMR beam onto a focal region located within the tissue using an optical system; scanning the focal region within the tissue using a beam scanning system; and controlling the EMR source using a controller to generate an EMT beam having a plurality of pulses, wherein at least one of the plurality of pulses has a pulse duration that is not less than about 100 microseconds. In some embodiments, the window includes a first window, a second window separated from the first window, and a coolant chamber located between the first window and the second window. The coolant chamber is configured to contain a coolant including a fluorocarbon-based fluid that is substantially non-absorbent of the EMR beam.

[0039] In some embodiments of the method, at least one of the plurality of pulses has a pulse energy that is not greater than about 100 mJ.

[0040] In some embodiments of the method, the method further includes cooling the coolant to a temperature within the range of about -20°C to about 20°C using a cooling device.

[0041] In some embodiments of the method, the step of focusing the EMR beam is performed with a numerical aperture (NA) of at least about 0.2.

[0042] In some embodiments of the method, the method further includes introducing an optical tissue clearing medium between the window assembly and the tissue, the optical tissue clearing medium including at least one of glycerin, polyethylene glycol, and phosphate buffered saline.

[0043] In some embodiments of the method, the EMR source further includes a beam shaper configured to shape a lateral ring-shaped energy profile. In some variations of the method, the beam shaper includes an axicon.

[0044] In some embodiments of the method, the method further includes controlling the EMR source using a controller to ensure that the window assembly cools the tissue to a predetermined temperature before generating the EMR beam.

[0045] In some embodiments of the method, the method further includes controlling the EMR source using a controller to ensure that the window assembly cools the tissue for a predetermined period before generating the EMR beam.

[0046] In some embodiments of the method, the method further includes controlling at least one parameter of the EMR beam, including one or more of the inner diameter of the ring-shaped energy profile, the outer diameter of the ring-shaped energy profile, the thickness of the ring-shaped energy profile, and the depth of the focal region within the tissue.

[0047] According to some embodiments, the system includes an EMR source configured to generate an EMR beam having a wavelength in the range of from about 1400 nm to about 3500 nm, a collimator configured to collimate the EMR beam into a collimated beam width, and a beam shaper including a first axicon and a second axicon configured to shape the EMR beam into a laterally annular energy profile, wherein the first axicon and the second axicon are separated by a separation distance along an optical axis, an inner diameter of the annular energy profile is related to the separation distance, and a thickness of the annular energy profile is related to the collimated beam width; an optical system configured to focus the EMR beam into a focal region located within tissue with a numerical aperture of at least about 0.2; a beam scanning system configured to scan the focal region within the tissue; a window assembly located downstream of the beam from an optical system configured to cool the tissue when the EMR beam is transmitted and in contact with an outer surface of the tissue, the window assembly including a first window, a second window separated from the first window, and a coolant chamber located between the first window and the second window, the coolant chamber configured to contain a coolant including a fluorocarbon-based fluid that is substantially non-absorbent of the EMR beam; a cooling device configured to cool the coolant to a temperature within a range of from about -20 °C to about 20 °C; and a controller configured to control the EMR source to ensure that the window assembly cools the tissue to a predetermined temperature or for a predetermined time before generating the EMR beam, and to control the EMR source to generate the EMR beam in a plurality of pulses, wherein at least one of the plurality of pulses has a pulse duration no less than 100 microseconds, wherein at least one of the EMR source, the optical system, and the beam scanning system is configured to control one or more parameters of the EMR beam, including one or more of an inner diameter of the annular energy profile, an outer diameter of the annular energy profile, a thickness of the annular energy profile, and a depth of the focal region within the tissue.

[0048] Embodiments of the present disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0049]

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[0050] Note that the drawings are not necessarily to scale. The drawings are intended to show only typical aspects of the subject matter disclosed herein and should not, therefore, be regarded as limiting the scope of the present disclosure. The systems, devices, and methods specifically described herein and shown in the accompanying drawings are non-limiting exemplary embodiments.

DETAILED DESCRIPTION OF THE INVENTION

[0051] To provide a general understanding of the structure, function, manufacture, and use principles of the devices and methods disclosed herein, specific exemplary embodiments are described herein. One or more examples of these embodiments are shown in the accompanying drawings. Those skilled in the art will understand that the devices and methods specifically described herein and shown in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present disclosure is defined only by the claims. Features illustrated or described in connection with an exemplary embodiment can be combined with features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure.

[0052] Embodiments of the present disclosure are described in detail below with respect to fractional treatments including skin rejuvenation and skin resurfacing, for example, fractional treatments for acne, chickenpox and surgical scars, periorbital and perioral wrinkles, photoaging changes, facial pigmentation disorders, and stretch marks. Additional treatments related to the present disclosure include the treatment of pigmentary conditions of the skin such as melasma, and other pigmentary conditions such as granuloma annulare.

[0053] However, the disclosed embodiments can be used for the treatment of other pigmentary and non-pigmentary diseases and other tissue and non-tissue targets without limitation. Examples of pigmentary diseases can include, but are not limited to, post-inflammatory hyperpigmentation (PIH), dark skin surrounding eyes, dark eyes, cafe au lait patches, Becker’s nevi, Nevus of Ota, congenital melanocytic nevi, freckles, and lentigo. Additional examples of pigmented tissue and structures that can be treated include hemosiderin-rich structures, pigmented gallstones, tissues containing tattoos, and structures rich in lutein, zeaxanthin, rhodopsin, carotenoid, biliverdin, bilirubin, and hemoglobin. Examples of targets for the treatment of non-pigmented structures, tissues, and conditions can include, but are not limited to, hair follicles, hair shafts, vascular lesions, infectious conditions, sebaceous glands, acne, etc.

[0054] For example, methods for treating various skin conditions, such as for cosmetic purposes, can be implemented using the systems described herein. Such methods can be performed by a physician, but it can be understood that non-physicians, such as estheticians and other appropriately trained personnel, can use the systems described herein to treat various skin conditions with or without the supervision of a physician.

[0055] Furthermore, in the present disclosure, components with similar names in the embodiments generally have similar characteristics, and within a particular embodiment, each characteristic of the components with the same name respectively is not necessarily fully described. Also, in the description of the disclosed systems, devices, and methods, as long as linear or circular dimensions are used, such dimensions are not intended to limit the types of forms that can be used in combination with such systems, devices, and methods. Those skilled in the art will recognize that dimensions equivalent to such linear and circular dimensions can be readily determined for any geometric form. The size and shape of the systems and devices, as well as their components, can depend at least on the size and form of the components used by the systems and devices, the methods and procedures in which the systems and devices are used, and the anatomical structure of the subject to which the systems and devices are applied.

[0056] Generally, a high numerical aperture (NA) optical treatment system that can focus electromagnetic radiation (EMR) (e.g., a laser beam) onto a treatment area of tissue is described. The focused laser beam can transmit optical energy to the treatment area without damaging the surrounding tissue. The transmitted optical energy can, for example, treat a treatment area in the dermis layer of the skin without affecting the surrounding areas (e.g., the overlying epidermis layer, other parts of the dermis layer, etc.). In other embodiments, the transmitted optical energy can induce tattoo removal or alteration, or hemoglobin-related treatments.

[0057] Exemplary methods and apparatuses for treating skin conditions with light or light energy are disclosed in U.S. Patent Application Publication No. 2016 / 0199132, entitled "Methods and Apparatuses and Methods for Treating Melasma of the Skin," and in U.S. Provisional Application No. 62 / 438,818, entitled "Methods and Apparatuses for the Treatment of Dermal Melasma," each of which is hereby incorporated by reference in its entirety.

[0058] Generally, a system and corresponding method for treating pigmentation conditions are provided. As discussed in more detail below, the disclosed system and method use electromagnetic radiation (EMR), such as a laser beam, to deliver a predetermined amount of energy to a target tissue. The EMR can be focused to a focal region, which can be translated or rotated in any direction relative to the target tissue. The predetermined amount of radiation can be configured to thermally ablate or damage a portion of the tissue. In this way, a predetermined amount of energy can be delivered to any location within the target tissue for treatment to improve its appearance.

[0059] Referring now to FIG. 1, a radiative treatment system 100 is shown. An electromagnetic radiation (EMR) source (e.g., a laser source) 110 generates an EMR beam (e.g., a laser beam) 112 having a wavelength in the range of about 1000 nm to about 12,000 nm, e.g., about 1550 nm. According to some embodiments, the EMR beam 112 has a substantially transverse ring energy profile (e.g., TEM01*) from the EMR source 110. According to other embodiments, a beam shaper 114 forms the EMR beam to generate a transverse ring energy profile. FIG. 1 shows a beam shaper 114 using two axicons. A first axicon 116 having a first wedge angle receives the EMR beam 112 and generates a Bessel beam 118. As the Bessel beam propagates, a diverging ring energy profile is formed. The diverging ring energy profile 120 is collimated by a second axicon 122 into a collimated EMR beam having a transverse ring energy profile 124. According to some embodiments, the second axicon 122 has a second wedge angle that is substantially equal to the first wedge angle of the first axicon 116. Thereafter, the ring energy profile 124 is directed toward a focus optic 128. Some examples of the focus optic 128 include a converging optic (e.g., a plano-convex lens) and an axicon. The focus optic 128 focuses the EMR beam and directs it toward tissue 130 (e.g., skin). In some cases, the focus optic focuses the EMR beam with a numerical aperture (NA) of at least about 0.2 (e.g., from about 0.3 to about 0.5). According to some embodiments, a window assembly 132 is positioned between the focus optic 128 and the tissue 130. The window assembly 132 is substantially transparent at the wavelength of the EMR beam 124. Exemplary window materials include glass, quartz, and sapphire.In some embodiments, the window assembly 132 is cooled and used to cool the tissue 130 during treatment. Generally, the window assembly 132 is disposed in contact with the outer surface of the tissue during operation of the device 100. According to some embodiments, the window assembly 132 includes two windows, namely a first window 134 and a second window 136, and a cooling chamber 138 is located between the two windows. The cooling chamber is configured to contain a coolant. In some embodiments, the flow of the coolant 140 passes through the coolant chamber 138. In some embodiments, the coolant includes one or more of a dielectric fluid, a fluorocarbon-based fluid, ethylene glycol, propylene glycol, water, and antifreeze. Often, the coolant is selected to be generally (e.g., greater than about 50%) transmissive at the wavelength of the EMR beam 124. For example, an exemplary embodiment includes an EMR beam 124 having a wavelength of 1550 nm and a coolant containing a fluorocarbon-based fluid (e.g., Fluorinert (trademark) from 3M) that is substantially transmissive at 1550 nm. In some embodiments, a medium 142 is disposed between the bottom surface of the window assembly 132 and the outer surface of the tissue 130. In some variations, this medium 142 acts to match the refractive index of the window assembly 132 to that of the tissue 130. In some other variations, the medium penetrates the tissue. Examples of the medium 142 include glycerol, phosphate buffered saline (PBS), polyethylene glycol (PEG) 400, and other suitable biocompatible materials having a refractive index approximately equal to that of the skin (e.g., about 1.4). In some embodiments, the system 100 further includes a controller 150 for controlling the EMR source 110. For example, in some embodiments, it is advantageous for the EMR source 110 to be controlled in response to the cooling of the tissue so that only the cooled tissue is irradiated. In some cases, the controller 150 is configured to control the EMR source to ensure that the window assembly cools the tissue to a predetermined temperature before generating the EMR beam.In some other cases, the controller 150 is configured to control the EMR source to ensure that the window assembly is cooled for a predetermined period before generating the EMR beam. According to some embodiments, a temperature sensor 152 (e.g., a thermocouple or a thermistor) is used to directly measure the temperature of the tissue. Alternatively, the temperature of a component in thermal communication with the tissue is measured by the temperature sensor. For example, the temperature of the coolant when flowing out of the coolant chamber 138 can be used as an indicator of the tissue temperature.

[0060] In some embodiments, the controller 150 is further configured to communicate with one or more of the EMR source 110, the beam shaper 114, and the focusing optics 128 to control one or more parameters of the EMR beam. Exemplary EMR beam parameters include the inner diameter of the ring-shaped energy profile, the outer diameter of the ring-shaped energy profile, the thickness of the ring-shaped energy profile, and the depth of the focal region within the tissue. According to some embodiments, the EMR beam is scanned across the entire skin tissue, for example, to generate a number of thermally damaged locations within the tissue to provide, for example, fractional therapy. Examples of systems and methods related to the scanning of a high NA EMR beam are incorporated herein by reference in their entirety from U.S. Patent Application No. 16 / 219,801, titled "Electromagnetic Radiation Beam Scanning System and Method," and International Application No. PCT / US2018 / 065508, titled "Scanning System for EMR-Based Tissue Therapy."

[0061] Referring to FIG. 2, flowchart 200 shows a method for irradiating tissue according to some embodiments. First, the tissue is cooled (210) using a window assembly disposed in contact with the outer surface of the tissue. According to some embodiments, the window assembly includes two windows, a first window and a second window, with a cooling chamber disposed between the two windows. The cooling chamber is configured to contain a coolant. In some embodiments, the flow of the coolant passes through the coolant chamber. In some embodiments, the tissue is cooled to a predetermined temperature prior to any subsequent step of method 200. In some embodiments, the tissue is cooled for a predetermined time prior to any subsequent step. In some cases, cooling the tissue to a predetermined temperature for a predetermined time can prevent thermal damage to the outer layer of the tissue (e.g., the epidermis), thereby reducing downtime.

[0062] According to some embodiments, a temperature sensor is used to measure the temperature associated with the tissue, e.g., the temperature of a component in contact with (and thus in thermal communication with) the tissue. Exemplary temperature sensors include thermistors, thermocouples, and infrared temperature sensors. The temperature sensor may directly detect the temperature of the tissue or the temperature of another material related to the temperature of the tissue (e.g., the coolant flowing out of a contact cooling assembly in contact with the tissue).

[0063] Next, an electromagnetic radiation (EMR) beam is generated (220). The EMR beam includes a transverse ring energy profile (e.g., TEM01* or donut energy profile). Next, the EMR beam is focused to form a focal region (230). Typically, the EMR beam is focused using one or more optical systems (e.g., a converging lens and / or an axicon). In some variations, the EMR beam is focused with a numerical aperture (NA) of about 0.2 or greater. Finally, the EMR beam is directed toward the tissue such that the focal region is at least partially located within the tissue (i.e., under the outer surface of the tissue) (240). In some variations, directing the EMR at the tissue (240) additionally includes scanning the EMR beam, whereby the focal region moves within the tissue. Scanning of the EMR is typically performed along at least one of three axes (e.g., an axis perpendicular to the optical axis and an axis parallel to the optical axis). For example, the focal region can be scanned not only in depth within the tissue but also laterally within the tissue. In some embodiments of method 200, an optical tissue clearing medium is introduced into the tissue. For example, in some cases, the optical tissue clearing medium is introduced onto the surface of the tissue between the tissue and the window assembly. In some embodiments, method 200 further includes the step of controlling at least one parameter of the EMR beam. Exemplary parameters of the EMR beam include the inner diameter of the ring-shaped energy profile, the outer diameter of the ring-shaped energy profile, the thickness of the ring-shaped energy profile, and the depth of the focal region within the tissue. [Exemplary Embodiments]

[0064] Referring now to FIG. 3A, an exemplary system 300 is shown with the front cover removed. The fiber laser source 310 outputs a laser. The exemplary fiber laser source 310 is a CW Er-Yb laser with an average output of 20 W (e.g., IPG part number ELR-20-1550-LP from IPG Photonics of Oxford, Massachusetts). The laser is collimated by the collimator 312 to a beam width of approximately 4 mm in diameter. Next, the collimated laser beam is shaped by the beam shaper 314 into a transverse ring (i.e., doughnut) energy profile (e.g., TEM01*). Next, the laser beam is directed along the optical train and ultimately focused and directed outside the window assembly 316 at the bottom surface of the exemplary system 300.

[0065] FIG. 3B shows a cross-sectional view of an exemplary system 300 and beam shaper 314 along section line B-B in FIG. 3A. In FIG. 3B, the beam shaper includes two identical axicons, a first axicon 320 and a second axicon 322. An exemplary axicon is Thorlabs part number AX2510-C, and this physical wedge angle is 10°. A laser beam having approximately a fundamental mode (i.e., a Gaussian transverse energy profile and M2 ≤ 1.5) is first formed into a Bessel beam by the first axicon 320 and then into a diverging transverse ring (i.e., donut) energy profile. The second axicon collimates the diverging transverse ring energy profile into a collimated transverse ring energy profile. The beam shaper is configured such that the inner diameter of the transverse ring energy profile is related proportionally to the separation distance between the first axicon 320 and the second axicon 322. According to an exemplary embodiment, the inner diameter of the transverse ring energy profile is nominally 4 mm. Here, the laser beam shaped into a transverse ring (i.e., donut) energy profile further propagates along the optical path and finally exits the system 300 through the window assembly 316. FIG. 3C shows a cross-sectional view of an exemplary system 300 and window 316 along section line C-C in FIG. 3A. The focusing optics 330 is located above the window 316 from the up-beam and focuses when the laser beam passes through the window assembly 316. Finally, the focusing optics 330 brings the laser beam to a focal region outside the window assembly 316, and when the window assembly is arranged to contact the tissue, the focal region is located within the tissue. An example of the focusing optics is Thorlabs part number A240-C, an aspheric lens with a nominal effective focal length of 8 mm. In some embodiments, the Z stage 331 houses the focusing optics 330 and adjusts the position of the focusing optics 330 along the optical axis, thereby affecting the depth of the focal region with respect to the window 316 (i.e., the depth of the focal region within the tissue). An exemplary Z stage 331 is Newscale PN:M3-FS from Newscale Technologies of Victor, New York.In some cases, the controller 150 is configured to control the Z-stage to affect the change in the depth of the focus region.

[0066] FIG. 3D shows a detailed view of an exemplary system 300 taken from the detailed circle D of FIG. 3C. The window assembly 316 is shown in more detail in FIG. 3D. A first window 340 is shown proximal to the focusing optical system 330. A second window 342 separated from the first window 340 is shown. A coolant chamber 344 is seen between the first window 340 and the second window 342. The coolant chamber 344 is sealed to receive coolant as it flows through the coolant chamber 344. The coolant is warmed by contact with the window assembly 316 and restored by a cooling device. Next, the coolant is cooled by a cooling device, for example, a thermoelectric cooling device (e.g., part number UC190 of Solid State Cooling, Wappingers Falls, NY), and recirculated through the window assembly 316. The disclosure regarding the window assembly for cooling during irradiation is included in U.S. Patent Application No. 16 / 237,367 to Dresser et al., which is incorporated herein by reference. The exemplary window assembly disclosed with reference to FIGS. 3A - D is described in more detail below.

[0067] An exemplary window assembly 316 for cooling during irradiation is schematically shown in various figures of FIGS. 3E - 3H. FIG. 3E shows a top isometric view of an assembly 316 (i.e., the portion of the cooling element 316 facing the EMR source / facing away from the target tissue). FIG. 3F shows a bottom isometric view of the window assembly 316 (i.e., the portion of the window assembly 316 facing the target tissue / facing away from the EMR source). FIG. 3G shows a bottom view of the window assembly 316. FIG. 3H shows a cross - sectional view of the window assembly 316 along the cross - section line shown in FIG. 3G. The exemplary window assembly 316 includes a frame 350. Referring to FIGS. 3E and 3G, the frame 350 has three datums 352. The datums 352 correspond to mounts on an energy - based device (e.g., 300), which can generate irradiation, thereby enabling the window assembly 316 to be detachably attached to and exchanged with the energy - based device. According to some embodiments, the datums 352 can approximate one or more geometric forms, such as planes, lines, and points. According to some variations, the datums 352 include a part of a kinematic mount (e.g., a Maxwell or Kelvin mount). The three datums 352 of the window assembly 316 can be arranged in a plane. The exemplary window assembly 316 includes a first window 340 sealed to the frame 350 by a first seal 354 and a second window 342 sealed to the frame 350 by a second seal 356. According to some embodiments, the first seal 354 and the second seal 356 include an adhesive. Examples of adhesives can include photocurable adhesives, silicones, and epoxies. According to other embodiments, the first seal 354 and / or the second seal 356 include a weld, a braze, or a solder, and the edges of the corresponding first window 340 and / or second window 342 can be metallized, sputtered, or coated with a material (e.g., metal) that enables this type of seal. Further, the second window 342 is attached to the frame 350 with one or more fasteners 358.As can be seen in FIGS. 3G and 3H, the fastener 358 of the window assembly 316 includes a clamp plate fixed in place by three machine screws. Additional examples of fasteners can include screws, clamps, snap rings, tabs, or any combination thereof. By attaching the second window 342 to the frame, the distal surface 360 of the second window 342 can be placed in firm contact with the tissue without introducing additional stress on the second seal 356, which can result in bending or movement of the distal surface 360 of the second window 342.

[0068] A change in the distance between the distal surface 360 and the optical system that focuses the EMR beam affects the working distance of the beam and the resulting focal position within the tissue. According to some embodiments, the distal surface 360 of the second window 342 can be placed in a predetermined shape (e.g., orientation, position, etc.) relative to the datum 352. For example, in some variations, the second window 342 is positioned parallel to a plane approximated by one or more datums 352 within a desired tolerance (e.g., 0.5 mrad). Further, the second window 342 can be positioned at an exact distance along the optical axis (e.g., the z-axis) within a desired tolerance (e.g., 0.05 mm). Further, according to some embodiments, both the first window 340 and the second window 342 are positioned parallel, and the predetermined distance between them can be within a desired tolerance (e.g., 0.5 mrad and 0.05 mm). For various reasons, the distal surface 360 of the second window in some embodiments includes a non-planar shape (e.g., convex or concave). For example, a convex distal surface 360 can be advantageous for compressing the tissue when placed in contact with the tissue.

[0069] Figure 3H shows chamber 344 within system 400. Chamber 344 is bounded by frame 350, first window 340, and second window 342. Chamber 344 can be sealed by first seal 354 and second seal 356. Chamber 344 is configured to contain a coolant. According to some embodiments, coolant flow is supplied to chamber 344 via one or more ports 362 that are in fluid communication with chamber 344. According to some embodiments, port 362 can provide a flow of coolant from a coolant flow source that is in fluid communication with port 362. In some implementations, the coolant flow source can be in fluid communication with port 362 via one or more fittings 364. FIGS. 3E and 3F show both coolant supply fitting 364a and coolant return fitting 364b for supplying coolant to chamber 344 and returning coolant from chamber 344.

[0070] According to some embodiments, the second window includes a material having a high thermal effusivity (e.g., quartz, sapphire, diamond, etc.). The higher the thermal effusivity, the more heat can be transferred from the tissue surface by the flow of the coolant. Similarly, according to some embodiments, the first window 340 includes a material having a lower thermal effusivity (e.g., glass or polymer). Implementations having the first window 340 with a lower thermal effusivity material can transfer less heat by the flow of the coolant through the first window. As a result, condensation may occur more slowly than in variations where the first window 340 includes a material with a high thermal effusivity. Further, in some embodiments, the first window has a greater thickness (e.g., about 1 mm) than the thickness of the second window (e.g., about 0.5 mm), allowing heat energy transfer to occur more freely across the second window. According to some variations, a non-condensing gas such as clean and dry air, nitrogen, carbon dioxide, or argon can be blown onto the first window to further prevent condensation.

[0071] FIG. 4A shows a simulated optical layout 400 according to some embodiments. A collimated Gaussian beam 410 is incident on a first axicon 412 that forms a Bessel beam 414 and propagates on the center. The Bessel beam 414 is incident on a second axicon 416 that forms a collimated lateral ring (i.e., donut) energy profile beam 418 and propagates on the center. The collimated lateral ring energy profile beam 418 is incident on an aspherical focusing optical system 420 that forms a lateral energy profile 422 for focusing on a focal region 424 and propagates on the center.

[0072] FIG. 4B shows a first simulated Gaussian beam profile 430 of the collimated Gaussian beam 410. FIG. 4C shows a first simulated lateral ring (i.e., donut) beam profile 432 of the lateral ring energy profile 422 that focuses 0.5 mm before the focal region 424. FIG. 4D shows a second simulated lateral ring beam profile 434 of the lateral ring energy profile (422) that focuses 0.2 mm before the focal region 424. And FIG. 4E shows a third simulated lateral ring beam profile 436 of the lateral ring energy profile 422 that focuses 0.1 mm before the focal region 424. The focusing lateral ring energy profile beam 422 has an irradiance across the beam profile that is greater than that of a Gaussian mode beam under the same conditions. Referring to FIG. 4F, a Gaussian energy profile 440 for the Gaussian beam 0.5 mm from the focus is shown. A lateral ring (i.e., donut) energy profile 442 for the lateral ring energy profile beam 0.5 mm from the focus is shown in FIG. 4G. The two beams characterized in FIGS. 4F and 4G both have the same output (e.g., 1 W). However, the local maximum irradiance of the Gaussian beam is much larger (e.g., 1.29 W / cm 2 ) than that of the lateral ring energy profile beam (e.g., 0.75 W / cm 2) Thus, the lateral ring beam transmits less peak energy density to the outer layer of the skin (e.g., the epidermis), while enabling the same amount of energy to be transmitted to the deeper layer of the skin (e.g., the dermis). Control of the reduction in the peak local energy density of the lateral ring beam is achieved by varying the width of the inner diameter of the lateral ring energy profile. The larger the inner diameter, the more energy is pushed out by the outer portion of the beam, and the peak energy density (or output density) within the beam decreases. Further, by increasing the numerical aperture of the focusing optical system 420, the peak local energy density can be decreased in both the Gaussian and lateral ring energy profiles. [Exemplary Ex Vivo Studies]

[0073] In accordance with several embodiments, numerous studies were conducted. This study was performed using a continuous wave (CW) Er-Yb fiber laser (IPG laser model: ELR-20-1550LP) with a maximum average output of 20 W and a wavelength of 1550 nm. The excised human tissue was irradiated using a high numerical aperture (e.g., NA of 0.4 or greater) focusing system. Split irradiation was achieved by pulsing the CW fiber laser when scanning the human tissue relative to the focusing system with an X-Y translation stage. Next, the human tissue was sectioned, stained, and examined. The viability was tested using nitro blue tetrazolium chloride (NBTC) staining. Specifically, NBTC staining acts on the proteins within the tissue. When these proteins are damaged (e.g., heat denatured), further staining by NBTC ceases and it appears unstained. [Study No. 1]

[0074] The first study was conducted to determine the pulse energy required for non-excisive thermal ablation of tissue using a Gaussian beam. The parameters used in Study No. 1 were as follows.

[0075]

Table 1

[0076] Some representative results of Study No. 1 are shown in the histological slides of FIGS. 5A - D. FIG. 5A shows a horizontal section obtained after irradiation with a pulse having an energy of about 10 mJ. FIG. 5B shows a vertical section obtained after irradiation with a pulse having an energy of about 10 mJ. Slight thermal denaturation of the protein is demonstrated by NBTC staining. In contrast, irradiation at a pulse energy exceeding 10 mJ, for example, about 40 mJ, was found to result in significant thermal destruction. FIG. 5C shows a horizontal section taken at about 300 micrometers below the tissue post - surface with 40 mJ per pulse irradiation. And FIG. 5D shows a vertical section of the tissue after 40 mJ per pulse irradiation. From Study No. 1, it was concluded that when this set of parameters was given, 10 mJ per pulse was the threshold pulse energy and below that, little or no thermal breakdown occurred. [Study No. 2]

[0077] Study No. 2 was performed to determine the effect of an optical tissue clearing medium on fractionated non - excisional in vitro irradiation. Samples of excised human tissue were placed in the optical tissue clearing medium for 4 hours before irradiation. The samples were immersed in a Petri dish containing the medium epidermis. Two optical tissue clearing media, phosphate - buffered saline (PBS) and glycerol, were tested. The parameters used in Study No. 2 are as follows.

[0078]

Table 2

[0079] Thermal destruction was only seen at 20 mJ per pulse in tissue samples immersed in the optical tissue clearing medium. Thermal destruction was not evident in NBTC viability staining at lower test pulse energies (5 mJ, 7 mJ, and 10 mJ). Some representative results of Study No. 2 are shown in the histological slides of FIGS. 6A - B. FIG. 6A shows a vertical section taken from tissue immersed in glycerol irradiated at 20 mJ per pulse. FIG. 6B shows a vertical section taken from tissue immersed in PBS irradiated at 20 mJ per pulse. [Study No. 3]

[0080] Study No. 2 was conducted to determine the effect of a lateral ring (i.e., doughnut) energy profile on fractionated non - excisional in vitro irradiation. Samples of excised human tissue were placed in the optical tissue clearing medium for 4 hours before irradiation. The samples were immersed in Petri dishes containing the medium epidermis. Two optical tissue clearing media, phosphate - buffered saline (PBS) and glycerol, were tested. The laser beam was shaped into the lateral ring energy profile as described above and focused on the tissue. The parameters used in Study No. 2 were as follows.

[0081]

Table 3

[0082] The histological results of Study No. 3 are described with reference to FIGS. 7A - E. FIG. 7A shows four histological images in a Cartesian layout with tissue immersed in glycerol on top, tissue immersed in PBS below, 10 mJ per pulse energy on the left, and 20 mJ per pulse energy on the right. Generally, a pulse energy of 20 mJ shows a more extensive and deeper thermal ablation than a pulse energy of 10 mJ. FIG. 7B shows a horizontal histological image of tissue immersed in glycerol and irradiated with a pulse energy of 10 mJ. FIG. 7C shows a horizontal histological image of tissue immersed in glycerol and irradiated with a pulse energy of 20 mJ. FIG. 7D shows a horizontal histological image of tissue immersed in PBS and irradiated with a pulse energy of 10 mJ. FIG. 7E shows a horizontal histological image of tissue immersed in PBS and irradiated with a pulse energy of 20 mJ. In the horizontal histology of tissue irradiated with a lateral ring energy profile, ring - shaped damage can be seen (e.g., FIG. 7C). The damage that appears as a ring in horizontal histology is a three - dimensional, thin - walled, hollow cone that reaches deep points within the tissue (e.g., 300 - 1000 micrometers). Within the cone of damage, there is tissue that has not been affected, as evidenced by the damage ring in the horizontal section (e.g., FIG. 7C) and the "Y" - shaped damage in the vertical section (e.g., FIG. 7A). The advantage of this irradiation pattern is that there is less damage to the epidermis compared to current fractionated irradiation techniques, and the damaged epidermis is damaged in a small, narrow width (e.g., 1 - 100 micrometers) surrounded by healthy (i.e., unaffected) tissue. [Parameter Selection]

[0083] The parameters related to the implementation of the embodiments of the present disclosure are outlined in the table below.

[0084] [Table 4]

[0085] In some embodiments, the aspect of the ring-shaped energy profile is controllable. FIG. 8A shows a pair of axicons 800 configured to generate a ring-shaped energy profile. The relationship between the separation (S) 810 of the two axicons 800 and the major diameter 812 of the resulting ring-shaped beam can be expressed as follows.

Equation

[0086] As described above, the collimated beam diameter 814 determines the ring-shaped energy profile width 816 as it enters the axicon pair 800. Thus, in some embodiments, the width of the ring-shaped energy profile 816 is controlled by varying the collimated beam diameter 814. For example, in some cases, a beam expander (e.g., a Galilean beam expander or a Keplerian beam expander) is used to expand (or decrease) the collimated beam diameter 814 before it reaches the axicon pair 800. The minor diameter (i.e., inner diameter) 818 can be represented by the major diameter (i.e., outer diameter) 812 of the ring energy profile. Specifically, the minor diameter 818 is equal to the major diameter 812 minus the diameter of the collimated beam 814, or φ minor = φ Major - φ beam where φ minor is the minor diameter 818, φ Major is the major diameter 812, φ beamIt is 814 for the beam diameter. According to some embodiments, one or more parameters related to the ring-shaped energy profile are controlled by a controller that manipulates the above parameters (e.g., the separation distance 810 of the axicons 800 and / or the beam expander rate). For example, in some cases, the separation distance 810 between the axicons 800 may be electronically manipulated using a motorized stage (e.g., Thorlabs PN: PT1-Z8). Similarly, in some cases (e.g., a Galilean beam expander), the optical path distance between two optical systems controls the beam expansion (or beam reduction) rate of the beam expander. In this case, the motorized stage can also be used to control the width of the beam 814 when entering the axicons 800.

[0087] Small-diameter fractional therapy results in smaller lesions and faster healing. For example, it has been revealed that partial damage exceeding a specific width (e.g., about 0.15 mm, 0.25 mm, or 0.5 mm) can cause scarring in some individuals. A width of partial damage smaller than what is currently commercially achievable minimizes downtime to the size of the threshold minimum partial damage width. Specifically, a beam size smaller than a single cell (e.g., about 20 micrometers) results in substantially the smallest possible fractional damage. As described above, in some cases, the exemplary optical systems described above achieve thermal damage to tissue on such a scale. In additional exemplary embodiments, such small, divided damage to the tissue is achieved by other exemplary optical systems.

[0088] Those skilled in the art will understand additional features and advantages based on the above embodiments. Accordingly, the disclosed embodiments are not particularly limited to those specifically illustrated and described, except as indicated by the appended claims. All publications and references cited herein are hereby expressly incorporated by reference in their entirety. [Additional Embodiments]

[0089] A further embodiment for affecting damage divided on the order of tens of micrometers is described with reference to FIGS. 9A - B. Referring to FIG. 9A, an optical system 900 for generating a Bessel beam focus region 910 is shown. The Bessel beam focus region, unlike a normal diffraction - limited focus region, has a focus width and a focus region length and can be separated from each other. Generally, the focus region length (i.e., the depth of field) is proportional to the square of the focus region radius (e.g., the Rayleigh range). By separating the focus region length from the focus region width, a very narrow (e.g., less than about 0.1 mm) and very long focus region (e.g., 0.5 mm or more) can be formed.

[0090] FIG. 9A schematically shows an optical path that can be used to generate an elongated beam. In this configuration, three axicons are used. The first axicon 912 and the second axicon 914 are used to shape the beam into a collimated annular beam 916, and the third axicon 918 is used to focus the beam into the Bessel beam focus region 910.

[0091] According to some exemplary embodiments, the width of the damage for partial treatment is related to the width of the first lobe of the Bessel beam focus region 910. The full - width at half - maximum ω o of the first lobe of the Bessel beam focus region 910 is a function of the wavelength λ, the wedge angle α of the axicon, and the refractive index n of the axicon. [Number]

[0092] Thus, according to some embodiments, such a selection of optical parameters is achieved by the selection of the axicon wedge angle of the third axicon 918. The following table shows some exemplary first lobe diameters of a 1550 - nm beam based on the axicon wedge angle.

[0093] [Table 5]

[0094] The length of the damage by the split treatment is related to the length of the Bessel beam focus region 910. The length of the Bessel beam (e.g., depth of field [DOF]) 920 formed by the axicon is a function of the width of the beam at the axicon. When an annular beam is used, the focus region length is a function of the width of the annular portion 922. Next, the width of the ring is, in turn, a function (e.g., half) of the width of the collimated beam 924, which is formed to form the annular beam. The length of the Bessel beam can be approximated using the following equation.

Equation

[0095] For example, when the output beam is 4 mm, the wavelength is 1550 nm, and the wedge angle is 20°, the length of the Bessel beam focus region approximates to 15 mm.

[0096] The working distance (WD) 926 between the tip of the third focus axicon 918 and the Bessel beam focus region 910 is a function of the inner diameter 928 of the annular ring 916. The working distance 926 measured from the tip of the axicon 918 can be approximated using the following equation with reference to FIGS. 9A - B.

Equation

[0097] The above equation is derived from the following two equations for X1 and X0. FIG. 9B shows the relationship of these equations.

Equation

[0098] As can be seen above, the small diameter (i.e., inner diameter) 928 of the ring energy profile 916 affects the operating distance 926. For example, the non-circular beam on which the axicon acts generates a Bessel beam focus region starting from the tip of the axicon. In some embodiments, the focus region 910 is controlled to a depth within the tissue (e.g., beneath the surface of the tissue) by controlling the small diameter 928 of the annular beam incident on the focusing axicon 918, which affects the operating distance 926 of the focus region 910. In some variations, the small diameter 928 of the annular beam 916 is a separation function between the first axicon 912 and the second axicon. The small diameter can be represented by the large diameter (i.e., outer diameter) 930 of the ring energy profile 916. Specifically, the small diameter 928 is equal to the large diameter 930 minus the diameter of the collimated beam 924, or φ minor = φ Major - φ beam is.

[0099] FIG. 10 shows an exemplary embodiment of a treatment system 1010. As shown in the figure, the treatment system 1010 includes a platform 1012, an emitter 1014, and a controller 1016. The platform 1012 may include one or more manipulators or arms 1020. The arm 1020 can be coupled to the emitter 1014 to perform various treatments on the target tissue 1022 of the subject 1024. The operations of the platform 1012 and the emitter 1014 may be directed by the user, manually or using the controller 16 (e.g., via a user interface). In certain embodiments (not shown), the emitter can have a handheld form factor and the platform 1012 may be omitted. In other embodiments, the platform may be a robotic platform and the arm may be communicatively connected to the controller for operation of the emitter.

[0100] The emitter 1014 and the controller 1016 (and optionally the platform 1012) can communicate via a communication link 1026, which can be any suitable type of wired and / or wireless communication link that transmits any suitable type of signal (e.g., electrical, optical, infrared, etc.) according to any suitable communication protocol.

[0101] Embodiments of the controller 1016 may be configured to control the operation of the emitter 1014. In one aspect, the controller 1016 can control the movement of the EMR 1030. As will be described in detail below, the emitter 1014 can include a source 1032 for the emission of the EMR 1030 and a scanning system 1034 for the operation of the EMR 1030. As an example, the scanning system 1034 may be configured to focus the EMR 1030 on a focal region and translate and / or rotate this focal region within space. The controller 1016 can transmit a signal to the source 1032 via the communication link 1026 to instruct the source 1032 to emit the EMR 1030 having one or more selected characteristics of wavelength, output, repetition rate, pulse duration, pulse energy, focusing characteristics (e.g., focal volume, Rayleigh length, etc.). In other aspects, the controller 1016 can transmit a signal to the scanning system 1034 via the communication link 1026 to instruct the scanning system 1034 to move the focal region of the EMR 1030 relative to the target tissue 1022 with one or more translational and / or rotational movements.

[0102] Embodiments of the treatment system 1010 and method are described herein in the context of a treatment environment within skin tissue, such as the skin layer. However, the disclosed embodiments can be used for the treatment of any tissue at any location of a subject without limitation. Examples of non-skin tissue can include, but are not limited to, mucosal tissue, genital tissue, visceral tissue, and surface and subsurface regions of gastrointestinal tract tissue. [Exemplary Manual Scanned System]

[0103] In some embodiments, a handheld system 1100 that is manually scanned (i.e., manually moved by a clinician) over the treatment area is used. FIGS. 11A - 11C illustrate exemplary embodiments that can be manually scanned. FIG. 11A shows a front view of the system 1100, FIG. 11B shows a side view of the system 1100, and FIG. 11C shows a cross - sectional view of the system 1100. Referring to FIGS. 11A - 11C, a fiber laser outputs a laser beam through a collimator 1110. The laser beam can be of any wavelength. Details of wavelength selection are described in detail above. The collimated laser beam is acted upon by a beam shaper 1112. As described above, the beam shaper 1112 takes the collimated laser beam out of the collimator 1110 and shapes it into a transverse ring energy profile. As shown in the cross - sectional view (FIG. 11C), the beam shaper has a first axicon 1112A, an alignment mirror 1112B, and a second axicon 1112C. The two axicons (1112A and 1112C) are used to shape the beam. The alignment mirror 1112B is used to align the laser beam onto the second axicon 1112C. Typically, axicons are very sensitive to misalignment, especially centering deviation. After the beam shaper 1112, the laser beam is reflected by a first galvanometer mirror 1114 and directed into and through a beam expander 1116. The beam expander is a Keplerian beam expander and includes a first positive optical element 1116A that focuses the beam to an intermediate focus and a second positive optical element 1116B that collimates the laser beam. In some cases, one or more of the beam expander optics are dynamic and can move along the optical axis. A linear stage 1116C moves the second positive optical element 1116B along the optical axis. An exemplary linear stage is the Newscale M3 - LS - 3.4 - 15 from Newscale Technologies, Victor, NY.The beam expander 1116 expands a collimated ring beam by a factor, for example, between 2 and 20X. When exiting the beam expander 1116, the laser beam is reflected by a static fold mirror 1118 that is focused by an objective lens 1119 (e.g., an aspherical focusing optical system, for example, Asphericon PN: AFL25 - 40 from Asphericon in Jena, Germany), reflected by a second galvanometer mirror 1120, and directed to exit through a contact window 1122. In some variations, the beam expander is an afocal relay system disposed at the conjugate distance between the first galvanometer mirror 114 and the objective lens 1119. As described in detail above, the contact window 1122 includes a first window 1122A, a second window 1122B separated from the first window, and a coolant chamber 1122C located between the first window 1122A and the second window 1122B. The second window 1122B has a convex tissue contact surface (i.e., outer surface). This shape is advantageous in some situations as it helps ensure reliable contact with the tissue during treatment and facilitates easier sliding from the tissue.

[0104] The handheld system 1100 described in FIGS. 11A - 11C is used to manually treat an area. When a clinician moves the handheld system 1100 over the treatment tissue, the second galvanometer mirror 1120 scans a line of points on the surface of the skin. Referring now to FIG. 12, an exemplary line of scan points 1200 is shown. The exemplary line 1200 includes eight individual points 1210 to which laser energy is delivered. The eight points 1210 are scanned in order from top to bottom (i.e., A - H) as shown in FIG. 12. After energy is delivered at the last point (i.e., point H), the line scan is repeated and resumed. The line has a width 1212 that is approximately equal to the value of the number of points 1210 multiplied by the pitch 1214 (i.e., the distance between adjacent points). Referring briefly again to FIGS. 11A - C, the line is scanned by the second galvanometer mirror 1120 of the handheld system 1100 along a manual scan direction 1216 that is generally perpendicular to the direction of the line scan 1200. [Exemplary Beam Scanning Systems]

[0105] In some embodiments, a beam scanning system and method are provided. The disclosure regarding such embodiments and the beam scanning system and method is described below. Generally, a beam scanning system and method can be classified into one or more of the types of pre-objective scanning, objective scanning, and post-objective scanning. Pre-objective scanning includes embodiments in which the beam is scanned (e.g., deflected, tilted, and / or inclined) before being directed to enter the objective (i.e., from the upper beam). Objective scanning includes embodiments in which the beam is scanned (e.g., deflected, tilted, and / or inclined), for example, by moving the objective. Post-objective scanning includes embodiments in which scanning (e.g., deflected, tilted, and / or inclined) is performed after the objective (i.e., from the downstream of the beam). [Pre-Objective Scanning]

[0106] FIG. 13 is a schematic diagram of a preobjective scanning system 2100 including an objective lens 2110 and a scanning unit 2112. The scanning unit 2112 can receive the laser beam 2104 from the laser source 2102 and direct the laser beam 2104 towards the objective lens 2110. The objective lens 2110 can receive the laser beam 2104 and direct the focused laser beam 2106 towards the focal volume 2108 in the treatment area of the tissue 2116 (e.g., skin). The scanning system 2112 can change the direction of the laser beam 2104 directed towards the objective lens 2110. For example, the scanning system 2112 can change the direction of the emitted laser beam along one or more scanning directions. The change in the direction of the laser beam 2104 impinging on the objective lens 2110 can cause the treatment path 2114 of the tissue 2116 to be traced in the focal volume 2108. The focal volume 2108 traverses the treatment path 2114 at the scanning speed. The scanning unit 2112 includes one or more optical elements that can direct the laser beam 2104 (or a portion of the laser beam 2104) towards the objective lens 2110. The preobjective scanning system 2100 can include a contact surface (e.g., as shown in FIG. 24) that can be disposed between the objective lens 2110 and the tissue 2116. The contact surface can apply pressure to the surface of the tissue 2116 and allow for the dissipation of heat from the surface of the tissue 2116.

[0107] FIG. 14 is a diagram showing an exemplary preobjective scanning system 2200. The scanning system 2200 includes a polygon scanner 2202 that can receive the incident laser beam 2104 (e.g., from the laser source 2102) and direct the incident laser beam 2104 towards the objective lens 2110 (e.g., an fθ lens). The emission direction of the laser beam 2104 (e.g., the angle of incidence at which the laser beam 2104 impinges on the objective lens 2110) can determine the position of the focal volume 2108 in the tissue 2116 (e.g., the x-y plane). According to some embodiments, the laser source 2102 provides a plurality of laser pulses that result in a plurality of corresponding focal volumes. The distance between two focal volumes resulting from sequential laser pulses is the focal volume pitch.

[0108] The polygon scanner 2202 can include a plurality of reflecting surfaces (for example, 2202a to 2202c). The polygon scanner 2202 can rotate about an axis 2204 along a rotation direction 2206. As the reflecting surfaces 2202a to 2202c rotate about the axis 2204 (for example, the angular positions of the reflecting surfaces 2202a to 2202c with respect to the axis 2204 change), the incident angle of the incident laser beam 2104 in the y-z plane changes. This changes the direction of the emitted laser beam 2104 along a first scanning direction (for example, along the y-axis). For example, when a reflecting surface (for example, 2202b) rotates about the axis 2204 along the rotation direction 2206, the direction of the emitted laser beam sweeps from a higher y value to a lower y value.

[0109] The axis 2204 can be tilted / rotated about the z-axis and / or the x-axis. This changes the incident angle of the incident laser beam 2104 in the x-z plane, thereby changing the direction of the emitted laser beam 2104 along a second scanning direction (for example, along the x-axis). The rotation of the polygon scanner 2202 and the rotation / tilt of the axis 2204 can enable a change in the direction of the emitted laser beam 2104 that can result in a scan of the emitted laser beam 2104 in the x-y plane.

[0110] Based on the change in the direction of the emitted laser beam 2104, the objective lens 2110 can track the focal volume 2108 along one or more treatment paths within the tissue 2116. For example, a change in the direction of the emitted laser beam 2104 due to the rotation of the polygon scanner 2202 can move the focal volume 2108 along the y-axis. A change in the direction of the emitted beam due to the tilt of the axis 2204 can move the focal volume 2108 along the x-axis. In one embodiment, the preobjective scanning system 2200 may move along the x-axis with respect to the tissue 2116. This can result in tracking the position of the focal volume 2108 along the x-axis.

[0111] The focal volume 2108 can also move along a third treatment path, i.e., the z-axis. This may be accomplished by changing the objective lens 2110 along the z-axis (e.g., away from or towards the tissue 2116). Alternatively or additionally, the lens 2240 can be placed in the beam path of the incident or outgoing laser beam 2104. By changing the position of the lens 2240 along the beam propagation direction 2242 (also referred to as the optical axis), the position focal volume 2108 can be tracked along the z-axis (e.g., the depth of the tissue 2116).

[0112] FIG. 15 shows a beam bending plane 2300 for a pre-objective scanning system 2200. The scanning system 2200 can be miniaturized by bending the scanning system 2200 around the beam bending plane 2300 (e.g., by reducing the extent of the scanning system 2200 along the z-axis). This may be achieved, for example, by placing a mirror (e.g., a planar mirror) on the beam bending plane and orienting the mirror parallel to the x-y plane.

[0113] FIG. 16 shows an exemplary fθ lens 2400 that can be used as an objective lens in a pre-objective scanning system 2200. The incident laser beam 2104 can impinge on a reflecting surface 2402 (e.g., the reflecting surface 2202b of the polygon scanner 2202) that can direct the outgoing laser beam 2104 towards the fθ lens 2400. The orientation of the reflecting surface 2402 can determine the angle of incidence (e.g., the angle of incidence in the y-z plane) at which the outgoing laser beam 2104 impinges on the fθ lens. The angle of incidence can determine the position of the focal volume 2108 (e.g., along the y-axis).

[0114] FIG. 17 is a diagram showing an exemplary pre-objective scanning system 2500. The scanning system 2500 includes a mirror system that can receive a laser beam 2104 (e.g., via an optical fiber 2520) and direct the laser beam 2104 toward an objective lens 2110 (e.g., an fθ lens). The direction of the output laser beam 2104c can determine the position of a focal volume 2108 (e.g., within an x-y plane) within the tissue 2116.

[0115] The mirror system can include two scanning mirrors. The first scanning mirror 2506 can rotate (e.g., clockwise, counterclockwise, etc.) about a first axis 2522, and the second scanning mirror 2508 can rotate (e.g., clockwise, counterclockwise, etc.) about a second axis 2524. When the first scanning mirror 2506 rotates, the angle of incidence of the incident laser beam 2104 on the mirror 2506 changes. This changes the direction of the output laser beam 2104b along a first scanning direction (e.g., along the y-axis). When the second scanning mirror 2508 rotates, the angle of incidence of the laser beam 2104b on the scanning mirror 2508 changes. This changes the direction of the output laser beam 2104c along a second scanning direction (e.g., along the x-axis). The rotation of the first scanning mirror 2506 and the second scanning mirror 2508 can enable a change in the direction of the output laser beam 2104c that can result in scanning of the output laser beam 2104c within the plane of the objective lens.

[0116] Based on the change in the direction of the output laser beam 2104c, the objective lens 2110 can track a focal volume 2108 (not shown) along one or more treatment paths within the tissue 2116. For example, a change in the direction of the output laser beam 2104c due to rotation of the first scanning mirror 2506 can cause the focal volume 2108 to move along a first treatment path. A change in the direction of the output laser beam 2104c due to rotation of the second scanning mirror 2508 can cause the focal volume 2108 to move along a second treatment path.

[0117] Scanning system 2500 can include a lens 2540 that can be disposed in the beam paths of laser beams 2104a, 2104b, 2104c. By varying the position of lens 2540 along the beam propagation direction, the position focus volume 2108 can be tracked along the depth of tissue 2116.

[0118] In some implementations of the scanning mirror system, the change in the direction of laser beam 2104b by the first scanning mirror 2506 can be large. This can prevent the laser beam 2104b from colliding with the second scanning mirror 2508. Also, the large angle of incidence of the laser beam 2104b on the second scanning mirror 2508 can result in a curved treatment path in the focal region. These effects can be prevented / reduced by including a third scanning mirror between the first scanning mirror 2506 and the second scanning mirror 2508. FIG. 18 is a diagram of an exemplary preobjective scanning system 2600 that includes a third scanning mirror 2507 that is downstream from the first scanning mirror 2506 and upstream from the second scanning mirror 2508. The third scanning mirror 2507 enables a smaller second scanning mirror 2508 and can prevent / reduce the curvature of the focal region treatment path.

[0119] Figures 19A to 19C show various scanning patterns of an emission beam (e.g., emission laser beam 2104) from a scanning unit 2112 (e.g., polygon scanner 2202, mirror system 2502, etc.). Figure 19A shows a first scanning pattern in which the emission beam scans in the following order: (a) movement from left to right (e.g., along the x-axis), (b) movement from top to bottom (e.g., along the y-axis), and (c) movement from right to left (e.g., along the negative x-axis). Figure 19B shows a second scanning pattern in which the emission beam scans in the following order: (a) movement from left to right (e.g., along the x-axis), (b) superposition of movement from top to bottom and movement from right to left, and (c) movement from left to right. Figure 19C shows a third scanning pattern in which the emission beam scans in the following order: (a) superposition of movement from left to right and movement from top to bottom, and (b) superposition of movement from right to left and movement from top to bottom. Movement of the light beam (e.g., from left to right, from right to left, from top to bottom, etc.) can be obtained by clockwise or counterclockwise rotation of scanning mirrors 2506, 2507, 2508, or rotation / slanting of the axis of polygon scanner 2202.

[0120] Figure 20 is a diagram showing an exemplary preobjective scanning system 2800. The scanning system 2800 includes a prism system 2802 that can receive an incident laser beam 2104 (e.g., via an optical fiber 2820) and transmit an emission beam 2105 (see Figure 21) toward an objective lens 2110 (e.g., an fθ lens). The direction of the emission beam 2105 can determine the position of the focal volume 2108 within the tissue 2116.

[0121] FIG. 21 shows a prism system 2802 that can be used with a pre-objective scanning system 2800. The prism system 2802 includes a first prism 2806 and a second prism 2808 that can rotate about a common axis 2822. Each prism can change the direction of an incident light beam by a characteristic angle. When both the first prism 2806 and the second prism 2808 are perfectly aligned, the direction of the incident laser beam changes by twice the characteristic angle. When the first prism 2806 and the second prism 2808 are completely misaligned, the direction of the incident laser beam remains unchanged. Along all other orientations of the prisms 2806, 2808, the direction of the incident laser beam can be changed to an angle within the range from 0 degrees to twice the characteristic angle.

[0122] When both of the prisms 2806, 2808 rotate at the same angular velocity (e.g., their relative orientation does not change during rotation), the output beam 2105 scans along a circular treatment path. When the prisms 2806, 2808 rotate at different angular velocities, their relative orientation changes during rotation. For example, the pair of prisms swings between a fully aligned state (where the direction of the output beam is off by twice the characteristic angle) and a fully misaligned state (where the direction of the output beam does not change).

[0123] FIG. 22 shows the scanning pattern of the output beam 2105 generated from a prism system 2802 in which the angular velocities of the first prism and the second prism are different. The output beam forms a spiral pattern, and the output beam 2105 spirals inward (e.g., until it reaches the center), and then an outward spiral may follow.

[0124] FIG. 23 is an example of an exemplary pre-objective scanning system 3100. The scanning system 3100 includes a scanning unit 3102 connected to an optical fiber 3110 that can guide a laser beam 2104. The scanning unit 3102 can include a first actuator 3106 and a second actuator 3108. The first actuator can rotate a portion of the optical fiber 3110 (e.g., the tip of the fiber proximate to the objective lens 3112) about the x-axis. This changes the direction of the emitted laser beam 2104 along a first scanning direction (e.g., along the y-axis). The second actuator 3108 can rotate a portion of the optical fiber 3110 (e.g., the tip of the optical fiber proximate to the objective lens 3112) about the y-axis. This changes the direction of the emitted laser beam 2104 along a second scanning direction (e.g., along the x-axis). Actuation by the first and second actuators can enable a change in the direction of the emitted laser beam 2104 that can result in scanning of the emitted laser beam 2104 in the plane of the objective lens 3112 (e.g., the x-y plane). Based on the change in the direction of the emitted laser beam 2104, the objective lens 3112 (e.g., an fθ lens) can track the focal volume 2108 along one or more treatment paths within the tissue 2116.

[0125] FIG. 24 is an illustration of an exemplary pre-objective scanning system 3200. The scanning system 3200 includes a scanning unit 3202 coupled (e.g., rigidly coupled) to an optical fiber 3210 that can guide a laser beam 2104. The scanning unit 3202 can include a six-axis actuator 3206 and a support arm 3208. A portion of the optical fiber 3210 can be rigidly coupled to a mounting position 3230 on the six-axis actuator 3206. The support arm 3208 can support the portion of the optical fiber proximate to the tissue 2116.

[0126] The six-axis actuator 3206 can move the optical fiber 3210 along the x, y, and z axes. Additionally or alternatively, the six-axis actuator 3206 can rotate the optical fiber 3210 about the x, y, and z axes. The tip of the optical fiber 3210 may be coupled to an objective lens 3212 that can focus the emitted laser beam 2104 onto the focal volume 2108 within the tissue 2116. The preobjective scanning system 3200 can also include a contact surface 3216 that can be placed in the optical path of the emitted laser beam 2104 between the objective lens 3212 and the tissue 2116.

[0127] The focal volume 2108 can be moved along a first treatment path (e.g., along the x-axis) by rotating the optical fiber about the y-axis. The focal volume 2108 can also be moved along a second treatment path (e.g., along the y-axis) by rotating the optical fiber about the x-axis. In some implementations, it may be desirable to change the distance between the tip of the optical fiber 3210 and the tissue 2116 (e.g., move the tip of the optical fiber along the z-axis) during rotation to ensure that the focal volume 2108 remains at a fixed depth within the tissue 2116. [Objective Scanning]

[0128] Figure 25 is a schematic diagram of a rotary objective scanning system 3300. The rotary objective scanning system 3300 can receive a laser beam 3304 from a laser source 3302. The scanning system 3300 includes an objective lens (not shown) that focuses the laser beam 3304 and directs the focused laser beam 3306 to a focal region 3308 within a treatment region 3310 of tissue 3311 (e.g., skin). As the objective lens moves (e.g., relative to the scanning system 3300 and / or by movement of the overall scanning system 3300), the focal region can trace a treatment path 3312 through the treatment region 3310. The treatment path 3312 can have a path shape (e.g., circular, elliptical, etc.). The scanning system 3300 includes optical elements that can direct the laser beam 3304 (or a portion of the laser beam 3304) toward the moving objective lens.

[0129] The scanning system 3300 can also include an interface (also referred to as a “base,” “window,” or “contact surface”) that can stabilize the treatment region 3310 and / or facilitate control and uniformity of the irradiation profile. For example, the interface can fix the treatment region 3310 by applying pressure and / or by including a gel pad between the interface and the treatment region. The pressure applied by the interface on the treatment region 3310 may be detected by a pressure detector. The interface can also include a contact sensor that detects relative movement between the skin and the interface. The pressure provided by the interface to the treatment region can also whiten (or remove some blood from) the volume of the treatment region being irradiated. This can result in selectivity of absorption of the focused laser beam 3306 by the treatment region (e.g., pigmented cells in the treatment region) while reducing the risk of unwanted damage to blood vessels.

[0130] The interface can cool / dissipate heat from the treatment area 3310 that may be generated, for example, by heating the treatment area 3310 with the focused laser beam 3306. The interface may be manufactured from a material suitable for heat dissipation (such as sapphire, diamond, glass, etc.). In some implementations, the interface can include a cooling system that can prevent the temperature of the treatment area from exceeding a threshold temperature. The cooling system can include a temperature sensor that can detect the temperature of the treatment area. When the temperature exceeds the threshold temperature, a user can be notified and / or a cooling unit (such as a Peltier element, cryospray, conductive cold conduit, etc.) can be activated to cool the treatment area.

[0131] The rotating objective scanning system can have various embodiments. Two exemplary embodiments of the rotating objective scanning system include an inner surface rotating objective scanning system and a lateral rotating objective scanning system, both of which are described below.

[0132] FIG. 26 schematically shows a system 3400 for scanning an electromagnetic radiation (EMR) beam 3402 according to some embodiments. A motor 3404 generates a rotational motion 3406. The motor 3404 is operably coupled to a reciprocating mechanism 3408 such that the rotational motion 3406 drives the reciprocating mechanism 3408. The reciprocating mechanism 3408 converts the rotational motion 3406 into a reciprocating motion 3410 that generally acts linearly along a first scanning axis 3412 (e.g., the x-axis). According to some embodiments, the reciprocating mechanism includes one or more of a cam and follower, a crank and slider, a Scotch yoke, and a multi-bar linkage. According to some embodiments, the reciprocating motion 3410 moves in a plurality of strokes (e.g., two strokes, a forward stroke, and a backward stroke). Typically, the reciprocating mechanism 3408 is configured to provide a constant speed to the reciprocating motion 3410. Alternatively, the reciprocating motion 3410 has a substantially flat velocity profile over at least a portion of one stroke.

[0133] Constant speed embodiments can employ a predetermined or desired constant speed. For example, the desired constant speed may be selected in the range from about 2 mm / S to about 5 m / S. In certain embodiments, the constant speed may be a selected percentage of the desired constant speed. For example, the selected percentage may be selected in the range from about 10% to about 90% (e.g., about 50%) of the desired constant speed.

[0134] The portion of the stroke of the reciprocating motion 3410 for which a constant speed is provided can be varied. For example, the portion of the stroke having a constant speed may be selected in the range from about 5% to about 95% (e.g., about 10% or more).

[0135] The focusing optical system 3414 is operably coupled to the reciprocating mechanism 3408 so as to be affected by the reciprocating motion 3410 and move. The focusing optical system 3414 is configured to focus the EMR beam 3402 along the optical axis 3418 onto the focus 3416. Therefore, the reciprocating motion 3410 of the focusing optical system 3414 moves the focus 3416 and the optical axis 3418 along the first scanning axis 3412.

[0136] According to some embodiments, the EMR beam 3402 is generated by an electromagnetic radiation (EMR) source 3420. Examples of EMR sources will be described in detail below. The EMR beam 3402 is delivered from the EMR source 3420 and directed to be incident on the focusing optical system 3414 by the optical system 3422. Typically, the optical system 3422 includes one or more reflective and / or transmissive optical systems. According to some embodiments, the optical system 3422 includes one or more moving dynamic optical elements 3424. For example, a dynamic optical element 3424 in the form of a reflector disposed along the optical axis 3418 and mechanically attached to the focusing optical system 3414 is affected by and moves according to the reciprocating motion 3410. As will be described in more detail below, the EMR source 3420 may be configured to operate in a pulsed mode according to a predetermined repetition rate. The relationship between the repetition rate of the EMR source and the constant speed of the reciprocating motion 3410 can determine the nominal pitch between consecutive pulsed foci along the first scanning axis 3412.

[0137] According to some embodiments, the housing 3426 is provided between the focusing optics 3414 and the focus 3416 along the optical axis. The housing 3426 is configured to contact a target surface, e.g., the surface of the target tissue 3428, via a contact surface. As shown in the figure, the focus 3416 is located downstream of the beam on the surface of the target tissue 3428. The housing 3426 will be described in more detail below. In one embodiment, the contact surface may be configured to cool the target tissue 3428. In other embodiments, one or more sensors (e.g., pressure sensors, contact sensors, temperature sensors, etc.) may be disposed within the housing and configured to measure one or more variables of the target tissue. The one or more variables can include at least one pressure, the contact between the contact surface and the target tissue, and the temperature.

[0138] According to some embodiments, the controller 3430 is used to control one or more of the motor 3404, the reciprocating mechanism 108, and the EMR source 3420. In some variations, the controller 3430 receives inputs from one or more sensors 3432 that measure at least one of the rotational motion 3406 and the reciprocating motion 3410.

[0139] FIG. 27 schematically shows a system 3500 that scans an electromagnetic radiation (EMR) beam with two axes. A motor 3502 generates a reciprocating motion 3504 that converts a rotational motion 3504 along a first scanning axis 3510 into a reciprocating motion 3508 and transmits it to a reciprocating mechanism 3506. According to some embodiments, the reciprocating motion 3508 includes a linear stroke and has a constant speed over a part of the linear stroke. A focusing optical system 3512 is mechanically attached to the output of the reciprocating mechanism 3506 so as to be affected and moved according to the reciprocating motion 3508. An intermittent mechanism 3514 is operatively coupled to the reciprocating mechanism 3506. The intermittent mechanism 3514 intermittently outputs an intermittent movement 3516. According to some embodiments, the intermittent mechanism includes one or more of a ratchet mechanism, a Geneva wheel mechanism, a cam mechanism, and an intermittent gear mechanism. According to some embodiments, the intermittent movement 3516 is linear, generally orthogonal to the first scanning axis 3510, and generally acts along a second scanning axis 3518.

[0140] According to some embodiments, the intermittent mechanism 3514 is configured to introduce (e.g., time-align) the intermittent movement 3516 when the reciprocating motion 3508 is at or near a particular position, e.g., at the start of the stroke, in the middle of the stroke, or at the end of the stroke.

[0141] According to some embodiments, a controller 3530 is used to control one or more of the motor 3502, the reciprocating mechanism 3506, and the intermittent mechanism 3514. In some variations, the controller 3530 receives inputs from one or more sensors 3532 that measure at least one of the rotational motion 3504, the reciprocating motion 3508, and the intermittent movement 3516. [Post-Objective Scanning]

[0142] FIG. 28 is a schematic diagram of a post-objective scanning system 3600. The post-objective scanning system 3600 includes an objective lens 3610 and a scanning unit 3612. The objective lens 3610 can receive the laser beam 3604 from the laser source 3602 and direct the focused laser beam 3606 towards the scanning unit 3612. The scanning unit 3612 can receive the focused laser beam 3606 and direct it towards a focal region 3608 within a treatment area of the tissue 3616 (e.g., skin). The scanning unit 3612 can enable the focal region 3608 to track a treatment path 3614. The scanning unit 3612 includes one or more optical elements that can direct the focused laser beam 3606 (or a portion of the focused laser beam 3606) towards the skin.

[0143] Exemplary parameters according to some embodiments of pre-objective and post-objective beam scanning devices are shown in the following table.

[0144] [Table 6]

[0145] The subject matter described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structural means disclosed herein and their structural equivalents, or combinations thereof. The subject matter described in this specification can be implemented as one or more computer program products, such as one or more computer programs tangibly embodied in an information carrier (e.g., a machine-readable storage device) for execution by, or to control the operation of, a data processing apparatus (e.g., a programmable processor, a computer, or multiple computers), or embodied in a propagated signal. A computer program (also called a program, software, software application, or code) can be written in any form of programming language, including a compiled or interpreted language, and can be distributed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program need not correspond to a file. A program can be stored in a portion of a file that holds other programs or data, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, subprograms, or portions of code). A computer program can be distributed to be executed on one computer or on multiple computers at one site, or distributed across multiple sites and interconnected by a communication network.

[0146] The processes and logic flows described herein, including method steps of the subject matter described herein, may be performed by one or more programmable processors executing one or more computer programs to operate on input data and generate output to perform the functions of the subject matter described herein. The processes and logic flows may also be performed as follows, and apparatus of the subject matter described herein may be implemented in special purpose logic circuitry, such as, for example, an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0147] Processors suitable for executing a computer program include, for example, both general purpose and special purpose microprocessors, and any one or more processors of any kind of digital computer. Typically, a processor receives instructions and data from a read-only memory or a random access memory, or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer also includes one or more mass storage devices, such as magnetic, magneto-optical, or optical disks, for storing data, or is operatively connected to receive data therefrom, transfer data thereto, or both. Information media suitable for embodying computer program instructions and data include all forms of non-volatile memory, including, for example, semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices), non-volatile memory magnetic disks (e.g., internal hard disks or removable disks), magneto-optical disks, and optical disks (e.g., CD and DVD disks). The processor and memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0148] To provide for interaction with a user, the subject matter described herein may be implemented on a computer having, for example, 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) that can provide the user with input to the computer. Other types of devices can also be used to provide interaction with the user. For example, feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback), and input from the user may be received in any form, including acoustic, speech, or tactile input.

[0149] The techniques described herein may be implemented using one or more modules. As used herein, the term "module" refers to computing software, firmware, hardware, and / or various combinations thereof. However, at a minimum, a module should not be interpreted as software that is not implemented in hardware, firmware, or recorded in a non-transitory processor-readable recordable storage medium (i.e., a module is not software itself). In fact, a "module" is always interpreted to include at least some physical non-transitory hardware, such as a processor or part of a computer. Two different modules may share the same physical hardware (e.g., two different modules may use the same processor and network interface). The modules described herein may be combined, integrated, separated, and / or replicated to support various applications. Also, functions described herein performed in a particular module may be performed by one or more other devices instead of or in addition to one or more other modules and / or functions performed in the particular module. Also, modules may be implemented in multiple devices and / or in other components, local or remote. Furthermore, modules may be moved from one device to another device and / or included in both devices.

[0150] The subject matter described herein may be implemented by a computing system that includes back-end components (e.g., data servers), middleware components (e.g., application servers), or front-end components (e.g., client computers having a graphic user interface or 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, and front-end components. The components of the system may 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) (e.g., the Internet).

[0151] Approximate language used throughout this specification and claims may be applied to modify any quantitative expressions that may be permissibly varied without resulting in a change in the basic function to which they relate. Unless otherwise stated or clear from the context, "approximately," "substantially," or "about" may include numbers (greater or less than a numerical value) that are within a range of 1%, or in some embodiments, within a range of 5%, or in some embodiments, within a range of 10% (except where such numbers exceed 100% of the permissible value).

[0152] Thus, terms such as "about," "approximately," or "substantially" or values ​​modified by such terms are not limited to the exact value specified. In at least some instances, the approximation language may correspond to the precision of an instrument for measuring the value. Throughout the specification and claims, range limitations may be combined and / or interchanged, and such ranges specifically include all subranges contained therein, unless the context or language dictates otherwise.

[0153] In the specification and claims, the articles "a" and "an" used herein should be understood to include plural referents unless clearly indicated to the contrary. When one, more than one, or all of the group members are used, a claim or description including "or" between one or more members of the group is deemed to be sufficient or relevant for a given product or process, unless otherwise indicated or otherwise indicated by the context. The disclosure also includes embodiments in which exactly one member of the group is present in, used in, or otherwise relevant to a given product or process. The disclosure also includes embodiments in which one or more or all of the group members are present in, used in, or otherwise relevant to a given product or process. Furthermore, it should be understood that the disclosed embodiments provide for all variations, combinations, and permutations of one or more limitations, elements, clauses, descriptive terms, etc. from one or more of the enumerated claims that are reliant on the same base claim (or any other claim), unless otherwise indicated or unless it is clear to one of ordinary skill in the art that a contradiction or inconsistency would arise. It is contemplated that all embodiments described herein are applicable to all different aspects of the disclosed embodiments, where appropriate. It is also contemplated that any embodiment or aspect may be freely combined with one or more other such embodiments or aspects, where appropriate. When elements are presented as lists (e.g., Markush group or similar format), it is understood that each subgroup of elements is also disclosed, and any element may be removed from the group. In general, when a disclosed embodiment or aspect of a disclosed embodiment is referred to as including a particular element, feature, etc., the particular embodiment or aspect of the disclosure consists of, or consists essentially of, such element, feature, etc. For the sake of brevity, these embodiments are not specifically described in so many words in all cases herein. It is also understood that any embodiment or aspect of the disclosure may be expressly excluded from the claims, regardless of whether a specific exclusion is mentioned in the specification.For example, any one or more of the active agents, additives, ingredients, any drug, organism type, disorder, subject, or combinations thereof may be excluded.

[0154] When a range is given herein, the embodiments of the present disclosure include those in which the endpoints are included, those in which both endpoints are excluded, and those in which one endpoint is included and the other endpoint is excluded. Unless otherwise specified, both endpoints should be assumed to be included. Furthermore, unless otherwise indicated or dictated otherwise by the context and understanding of one of ordinary skill in the art, it should be understood that values ​​given as ranges can assume any particular value or subrange within the stated range in other embodiments of the present disclosure, to the tenth of the unit of the lower limit of the range, unless otherwise indicated by the context. Also, when a series of numerical values ​​is described herein, the present disclosure includes embodiments in which the lowest associated value can be considered as a minimum value and the highest associated value can be considered as a maximum value, as well as any intermediate value or range defined by any two values ​​in the series. Numeric values ​​used herein include values ​​expressed as percentages.

[0155] Although a few variations have been described in detail above, other modifications or additions are possible.

[0156] In the above description and in the claims, phrases such as "at least one" or "one or more" may be followed by a conjoint list of elements or features. The term "and / or" may also appear in a list of more than one element or feature. Unless otherwise expressly or implicitly contradicted by the context in which it is used, such phrases are intended to refer to any of the listed elements or features individually, or any of the cited elements or features in combination with other cited elements or features. For example, the phrases "at least one of A and B," "one or more of A and B," and "A and / or B" are intended to mean "A only, B only, or A and B together," respectively. A similar interpretation applies to lists containing more than two items. For example, the phrases "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, and / or C" are intended to mean "A only, B only, C only, A and B together, A and C together, B and C together, or A, B and C together," respectively. Furthermore, use of the term "based on" above and in the claims is intended to mean "based at least in part on," thereby allowing for unrecited features or elements.

[0157] The subject matter described herein may be embodied in systems, devices, methods, and / or articles, depending on the desired configuration. The implementations described in the above description do not represent all implementations consistent with the subject matter described herein. Instead, they are merely some examples consistent with aspects related to the described subject matter. Although some variations have been described in detail above, other modifications or additions are possible. In particular, further features and / or variations may be provided in addition to those described herein. For example, the above implementations may relate to various combinations and subcombinations of the disclosed features, and / or combinations and subcombinations of some further features disclosed above. Furthermore, the logic flows depicted in the accompanying figures and / or described herein do not necessarily require the particular order or sequential order depicted to achieve the desired results. Other implementations may be within the scope of the claims.

Claims

1. A system comprising: an electromagnetic radiation (EMR) source configured to generate an EMR beam having a wavelength in the range of 1000 nm to 12000 nm; a beam shaper having a first axicon and a second axicon configured to shape the EMR beam into a transverse ring energy profile; an optical system configured to focus the EMR beam onto a focus located within the tissue; a beam scanning system configured to scan the focus within the tissue; a window assembly located below the optical system and configured to transmit the EMR beam and cool the tissue when placed in contact with the outer surface of the tissue; a controller configured to control the EMR source to generate the EMR beam in a plurality of pulses; wherein: the window assembly comprises: a first window; a second window separated from the first window; and a coolant chamber located between the first window and the second window and configured to contain a coolant comprising a fluorocarbon-based fluid that is non-absorptive of the EMR beam; at least one of the plurality of pulses has a pulse width of 100 microseconds or more; the system.

2. The system of claim 1, wherein the EMR beam has a wavelength in the range between 1000 nm and 4000 nm.

3. The system of claim 1, wherein the optical system is further configured to focus the EMR beam with a numerical aperture (NA) of at least 0.

2.

4. The system of claim 1, further comprising an optically tissue-transparent medium located between the window assembly and the tissue, the optically tissue-transparent medium comprising at least one of glycerin, polyethylene glycol, and phosphate-buffered saline.

5. The system of claim 1, wherein the controller is configured to control the EMR source to ensure that the window assembly cools the tissue to a predetermined temperature before generating the EMR beam.

6. The system of claim 1, wherein the controller is configured to control the EMR source to ensure that the window assembly cools the tissue for a predetermined period before generating the EMR beam.

7. ​ The system according to claim 1, wherein at least one of the plurality of pulses has a pulse energy not greater than 100 mJ. **Claim 8** The system according to claim 1, further comprising a cooling device configured to cool the coolant to a temperature within a range of -20°C to 20°C. **Claim 9** The system according to claim 1, wherein at least one of the EMR source, the optical system, and the beam scanning system is configured to control one or more parameters of the EMR beam, including one or more of an inner diameter of the transverse ring energy profile, an outer diameter of the transverse ring energy profile, a thickness of the transverse ring energy profile, and a depth of the focus in the tissue.

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