Feedback Detection for a Treatment Device

Abstract

According to some embodiments, a system for fractionated treatment of tissue includes: an electromagnetic radiation (EMR) source configured to generate an EMR beam having a transverse annular energy distribution; an optical device configured to focus the EMR beam onto a focal region located within the tissue; and a window assembly located downstream of the optical device, the window assembly being configured to cool the tissue when placed in contact with the outer surface of the tissue.

Description

[0001] Cross - Reference to Related Applications

[0002] 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 Devices and Methods", the entire content of which is incorporated herein by reference. BACKGROUND OF THE INVENTION

[0003] Currently, many energy-based devices are available for fractional treatment of the dermis. These methods include ablative lasers, non-ablative lasers, microneedles, and radiofrequency energy treatments. Generally, these currently available energy-based fractional treatments require damage to the exterior (e.g., the epidermis) of the skin being treated. In most cases, damage to the epidermis results in the skin appearing inflamed, blemished, or unhealthy immediately after treatment. Additionally, severe damage to the epidermis can lead to one or more infections and require additional medical treatment. This undesirable appearance results in a downtime after treatment that lasts until the epidermis heals, depending on the treatment parameters used (e.g., ablative vs. non-ablative), which can take from days to weeks. Most patients do not resume normal life until after the downtime following treatment. Accordingly, there is a need for an available fractional treatment system and method that can successfully affect the dermis while minimizing damage to the epidermis in order to minimize downtime after treatment. SUMMARY OF THE INVENTION

[0004] Skin rejuvenation is generally performed through fractional treatments. Energy-based time-sharing or fractional treatments refer to treatments in which only a portion of the tissue area is exposed to energy. For example, a fractional skin treatment can treat 25% of the skin area with a laser beam while leaving the remaining 75% of the skin area of that region untreated. Energy-based skin rejuvenation involves creating controlled micro-lesions within the collagen network. This micro-lesion causes a wound healing process in which new collagen is formed. The newly formed collagen tightens the skin, thereby making the skin look younger. Many skin rejuvenation fractional treatment systems work by using water as a chromophore to achieve photothermolysis.

[0005] Fractional treatments can generally be divided into two categories: ablative and non-ablative. Ablative treatments result in the removal of tissue and micro-lesions on the surface in addition to creating thermal lesions within the dermis. Non-ablative treatments generally do not result in tissue removal but only cause thermal disruption. The advantage of non-ablative fractional treatments over ablative fractional treatments is reduced downtime.

[0006] Energy-based fractionated treatment of tissue generally requires delivering a large amount of energy to and being absorbed by a selected portion of the tissue to achieve the desired destruction or damage. This destruction or damage is repeated over an area of the tissue such that small regions of damaged tissue (e.g., having a diameter of 0.1 mm to 10 mm) are interspersed with undamaged tissue. Then, during the healing period after treatment, the small regions of damaged tissue are replaced by new tissue. Causing damage within the dermis layer of the skin while minimizing damage to the overlying epidermis layer presents numerous technical challenges, some of which are listed below.

[0007] First, there are no known chromophores within the dermis layer of the tissue that are not present within the epidermis layer of the tissue. This means that radiation selected to be absorbed within the dermis will also be absorbed within the epidermis layer.

[0008] Second, since EMR will be absorbed equally well by both the epidermis and dermis layers of the skin, a greater energy density must be delivered to the dermis layer than to the epidermis. To achieve this, the EMR distribution must be altered such that the focused region of the EMR beam (i.e., the region of maximum energy density) is located within the dermis and only the non-focused region of the EMR beam (i.e., the region of minimum energy density) is directed towards the epidermis layer of the skin.

[0009] Third, skin tissue is a turbid medium, which means that radiation propagating through the skin will scatter. Radiation scattering within the skin tissue makes it more difficult to form a focused region (region of maximum energy density) at any depth within the tissue, thereby exacerbating the first and second challenges described above.

[0010] Fourth, the focused region (or region of maximum energy density) must be accurately positioned at a depth within the dermis layer of the skin. This ensures that the region of maximum energy density is located within the dermis and not within the epidermis to prevent unnecessary damage to the epidermis.

[0011] Fifth, the EMR beam is delivered from outside the tissue; thus, the epidermis experiences some minimal radiation and small thermal heating (i.e., less than the dermis). To address this fifth challenge, the epidermis layer directly overlying the treated dermis layer must be actively cooled to prevent thermal damage to the epidermis.

[0012] Accordingly, to provide fractionated treatment destruction to the dermis layer of skin tissue while minimizing damage to the overlying epidermis layer, a fractionated treatment system and method that address all of the above challenges are needed.

[0013] According to some embodiments, a system for fractionated treatment of tissue includes: an electromagnetic radiation (EMR) source configured to generate an EMR beam having a transverse annular energy distribution; an optical device configured to converge the EMR beam to a focal region located within the tissue; and a window assembly located downstream of the optical device, the window assembly being configured to cool the tissue when placed 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, wherein the coolant chamber is configured to contain a coolant that substantially does not absorb the EMR beam.

[0014] In some embodiments of the system, the EMR beam has a wavelength in the range between about 1000 nm and 4000 nm.

[0015] In some embodiments of the system, the coolant includes at least one of a dielectric fluid, a fluorocarbon-based fluid, water, an antifreeze, ethylene glycol, and propylene glycol.

[0016] In some embodiments of the system, the optical device is further configured to converge the EMR beam with a numerical aperture (NA) of at least about 0.2.

[0017] In some embodiments of the system, the system further includes an optically clear medium located between the window assembly and the tissue. In some cases, the optically clear medium includes at least one of glycerol, polyethylene glycol, and phosphate buffered saline.

[0018] In some embodiments of the system, the EMR source includes a beam shaper configured to shape the transverse annular energy distribution. In some versions of the system, the beam shaper includes an axicon.

[0019] In some embodiments of the system, the system further includes a controller. In some cases, the controller is configured to control the EMR source to ensure that the window assembly cools the tissue to a determined temperature before generating the EMR beam. In some cases, the controller is configured to control the EMR source to ensure that the window assembly cools the tissue for a determined period of time before generating the EMR beam.

[0020] According to some embodiments, a method for fractionated treatment of tissue includes: using a window assembly in contact with the outer surface of the tissue to cool the tissue; using an electromagnetic radiation (EMR) source to generate an EMR beam having a transverse annular energy distribution; and using an optical device to converge the EMR beam to a focal region located within the tissue. In some cases, 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, wherein the coolant chamber is configured to contain a coolant that substantially does not absorb the EMR beam.

[0021] In some embodiments of the method, the EMR beam has a wavelength in the range between about 1000 nm and 4000 nm.

[0022] 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.

[0023] In some embodiments of the method, the focusing of the EMR beam is performed at a numerical aperture (NA) of at least about 0.2.

[0024] In some embodiments of the method, the method further includes introducing an optically tissue-permissive medium between the window assembly and the tissue. In some cases, the optically tissue-permissive medium includes at least one of glycerol, polyethylene glycol, and phosphate buffered saline.

[0025] In some embodiments of the method, the EMR source further includes a beam shaper configured to shape a transverse annular energy distribution. In some versions of the method, the beam shaper includes an axicon.

[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 to a determined temperature before generating the EMR beam.

[0027] 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 determined period of time before generating the EMR beam.

[0028] According to some embodiments, a system for fractionated treatment of tissue includes: an electromagnetic radiation (EMR) source configured to generate an EMR beam having a wavelength in the range between about 1400 nm and 3400 nm; a beam shaper configured to shape the EMR beam into a transverse annular energy distribution, wherein the beam shaper includes an axicon; an optical device configured to focus the EMR beam to a focal region within the tissue at a numerical aperture (NA) of at least about 0.2; a window assembly located downstream of the optical device, the window assembly being configured to cool the tissue when placed in contact with the outer surface of the tissue, wherein 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, wherein the coolant chamber is configured to contain a coolant that substantially does not absorb the EMR beam and includes a fluorocarbon-based fluid; and a controller configured to control the EMR source to ensure that the window assembly cools the tissue to a predetermined temperature and for a determined period of time.

[0029] According to some embodiments, a system for fractionated treatment of tissue includes: an electromagnetic radiation (EMR) source configured to generate an EMR beam having a wavelength; a collimator configured to collimate the EMR beam to a certain width; a beam shaper including a first axicon and a second axicon, the beam shaper being configured to shape the collimated EMR beam into a transverse annular energy distribution, wherein the first axicon and the second axicon are separated by a certain distance along the optical axis, the distance being selected to achieve a desired inner diameter of the transverse annular energy distribution, and the width of the collimated EMR beam being selected to achieve a desired thickness of the transverse energy distribution; and an optical device configured to converge the EMR beam into a focal region within the tissue, thereby affecting the tissue within the focal region.

[0030] According to some embodiments, a system includes: an EMR source configured to generate an EMR beam having a transverse annular energy distribution and a wavelength in the range of about 1200 nm to about 12000 nm; an optical device configured to converge the EMR beam into a focal region located within the tissue; a beam scanning system configured to scan the focal region within the tissue; a window assembly located in the lower beam of the optical device, the window assembly being configured to transmit the EMR beam and cool the tissue when placed in contact with the outer surface of the tissue, wherein 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, wherein the coolant chamber is configured to contain a coolant, the coolant including a fluorocarbon-based fluid that substantially does not absorb the EMR beam; and a controller configured to control the EMR source to generate an EMR beam having a plurality of pulses, wherein at least one of the plurality of pulses has a pulse duration of not less than about 100 microseconds.

[0031] In some embodiments of the system, at least one of the plurality of pulses has a pulse energy of not greater than about 100 mJ.

[0032] In some embodiments of the system, the system further includes a cooler configured to cool the coolant to a temperature in the range of about -20°C to about 20°C.

[0033] In some embodiments of the system, the optical device is further configured to converge the EMR beam with a numerical aperture (NA) of at least about 0.2.

[0034] In some embodiments of the system, the system further includes an optically tissue-permissive medium located between the window assembly and the tissue, wherein the optically tissue-permissive medium includes at least one of glycerol, polyethylene glycol, and phosphate-buffered saline.

[0035] In some embodiments of the system, the EMR source additionally includes a beam shaper configured to shape the transverse annular energy distribution. In some versions of the system, the beam shaper includes an axicon.

[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 to a predetermined temperature before generating the EMR beam.

[0037] 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 of time before generating the EMR beam.

[0038] In some embodiments of the system, at least one of the EMR source, the optics, 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 annular energy distribution, the outer diameter of the annular energy distribution, the thickness of the annular energy distribution, and the depth of the focal region within the tissue.

[0039] According to some embodiments, a method includes: using a window assembly that contacts the outer surface of the tissue to cool the tissue; using an EMR source to generate an EMR beam having a transverse annular energy distribution and a wavelength in the range of about 1200 nm to 12000 nm; using optics to converge the EMR beam to a focal region located within the tissue; using an ortho-scanning system to scan the focal region within the tissue; and using a controller to control the EMR source to generate an EMT beam having a plurality of pulses, wherein at least one of the plurality of pulses has a pulse duration of 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 hold a coolant that includes a fluorocarbon-based fluid that substantially does not absorb the EMR beam.

[0040] In some embodiments of the method, at least one of the plurality of pulses has a pulse energy of not greater than about 100 mJ.

[0041] In some embodiments of the method, the method additionally includes using a cooler to cool the coolant to a temperature in the range of about -20°C to about 20°C.

[0042] In some embodiments of the method, the converging of the EMR beam is performed at a numerical aperture (NA) of at least about 0.2.

[0043] In some embodiments of the method, the method additionally includes introducing an optically tissue-clearing medium between the window assembly and the tissue, wherein the optically tissue-clearing medium includes at least one of glycerol, polyethylene glycol, and phosphate-buffered saline.

[0044] In some embodiments of the method, the EMR source additionally includes a beam shaper configured to shape the transverse annular energy distribution. In some versions of the method, the beam shaper includes an axicon.

[0045] In some embodiments of the method, the method additionally 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.

[0046] In some embodiments of the method, the method additionally includes using a controller to control the EMR source to ensure that the window assembly cools the tissue for a predetermined period of time before generating the EMR beam.

[0047] In some embodiments of the method, the method additionally includes controlling at least one parameter of the EMR beam, including one or more of the inner diameter of the annular energy distribution, the outer diameter of the annular energy distribution, the thickness of the annular energy distribution, and the depth of the focal region within the tissue.

[0048] According to some embodiments, the system includes: an EMR source configured to generate an EMR beam having a wavelength in the range between about 1400 nm and about 3500 nm; a collimator configured to collimate the EMR beam to a collimated beam width; a beam shaper including a first axicon and a second axicon, the beam shaper configured to shape the EMR beam into a transverse annular energy distribution, wherein the first axicon and the second axicon are separated along an optical axis by a separation distance, wherein an inner diameter of the annular energy distribution is related to the separation distance, and a thickness of the annular energy distribution is related to the collimated beam width; an optical device configured to converge the EMR beam to 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 optical device, the window assembly configured to transmit the EMR beam and cool the tissue when placed in contact with an outer surface of the tissue, wherein 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, wherein the coolant chamber is configured to contain a coolant, the coolant including a fluorocarbon-based fluid that substantially does not absorb the EMR beam; a cooler configured to cool the coolant to a temperature in the range of about -20 °C to about 20 °C; 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, control the EMR source to generate an EMR beam having a plurality of pulses, wherein at least one pulse of the plurality of pulses has a pulse duration of not less than 100 microseconds; and, wherein at least one of the EMR source, the optical device, 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 distribution, an outer diameter of the annular energy distribution, a thickness of the annular energy distribution, and a depth of the focal region within the tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Embodiments of the present disclosure will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0050] Figure 1 An apparatus for electromagnetic radiation (EMR) therapy according to some embodiments is schematically illustrated;

[0051] Figure 2 is a flow chart depicting a method for EMR therapy according to some embodiments;

[0052] Figure 3A is a schematic illustration of an exemplary embodiment of an apparatus for EMR therapy according to some embodiments;

[0053] Figure 3B is Figure 3A a cross-sectional view of the apparatus along line B-B;

[0054] Figure 3C is Figure 3A Cross-sectional view of the device along line C-C;

[0055] Figure 3D is Figure 3A Detailed view of the device at circle D;

[0056] Figure 3E Isometric view of the back of a contact window assembly according to some embodiments;

[0057] Figure 3F is according to some embodiments of Figure 3E Isometric view of the front of the contact window assembly;

[0058] Figure 3G is according to some embodiments of Figure 3E Front view of the contact window assembly;

[0059] Figure 3H is Figure 3E Side cross-sectional view of the window assembly;

[0060] Figure 4A Schematic diagram of the optical path layout for simulating a beam shaper according to some embodiments;

[0061] Figure 4B Shows a transverse Gaussian mode according to some embodiments;

[0062] Figure 4C Shows the transverse annular energy distribution 0.5 mm before focusing according to some embodiments;

[0063] Figure 4D Shows the transverse annular energy distribution 0.2 mm before focusing according to some embodiments;

[0064] Figure 4E Shows the transverse annular energy distribution 0.1 mm before focusing according to some embodiments;

[0065] Figure 4F Shows the energy distribution of a Gaussian beam 0.5 mm before focusing according to some embodiments;

[0066] Figure 4G Shows the energy distribution of the transverse annular (i.e., circular ring) energy distribution 0.5 mm before focusing according to some embodiments;

[0067] Figure 5A Shows the horizontal histology of a tissue sample from Study No. 1 discussed herein according to some embodiments;

[0068] Figure 5B Shows the vertical histology of tissue samples from Study No. 1 discussed herein according to some embodiments;

[0069] Figure 5C Shows the horizontal histology of tissue samples from Study No. 1 discussed herein according to some embodiments;

[0070] Figure 5D Shows the vertical histology of tissue samples from Study No. 1 discussed herein according to some embodiments;

[0071] Figure 6A Shows the vertical histology of tissue samples from Study No. 2 discussed herein according to some embodiments;

[0072] Figure 6B Shows the vertical histology of tissue samples from Study No. 2 discussed herein according to some embodiments;

[0073] Figure 7A Shows multiple vertical histological images of tissue samples from Study No. 3 discussed herein according to some embodiments;

[0074] Figure 7B Shows multiple horizontal histological images of tissue samples from Study No. 3 discussed herein according to some embodiments;

[0075] Figure 7C Shows multiple horizontal histological images of tissue samples from Study No. 3 discussed herein according to some embodiments;

[0076] Figure 7D Shows multiple horizontal histological images of tissue samples from Study No. 3 discussed herein according to some embodiments;

[0077] Figure 7E Shows multiple horizontal histological images of tissue samples from Study No. 3 discussed herein according to some embodiments;

[0078] Figure 8 Schematically shows an optical scheme for beam shaping according to some embodiments.

[0079] Figure 9A Schematically shows an optical scheme for fractionated treatment according to some embodiments;

[0080] Figure 9B Schematically shows an optical scheme for fractionated treatment according to some embodiments; and

[0081] Figure 10 Shows an exemplary embodiment of a treatment system;

[0082] Figure 11A Shows a front view of an exemplary embodiment of a treatment system;

[0083] Figure 11B Shows a side view of an exemplary embodiment of a treatment system;

[0084] Figure 11C Shows Figure 11B a cross-sectional view of an exemplary embodiment of;

[0085] Figure 12 Shows a line scan pattern according to some embodiments;

[0086] Figure 13 is a schematic diagram of a pre-objective scanning system;

[0087] Figure 14 is an illustration of an exemplary pre-objective scanning system;

[0088] Figure 15 Shows Figure 14 the beam folding plane of the pre-objective scanning system in;

[0089] Figure 16 Shows an exemplary f-θ lens;

[0090] Figure 17 is an illustration of an exemplary pre-objective scanning system;

[0091] Figure 18 is an illustration of an exemplary pre-objective scanning system;

[0092] Figures 19A to 19C Shows in relation to Figure 14 、 Figure 17 and Figure 18 the exemplary scanning patterns associated with the pre-objective scanning system in;

[0093] Figure 20 is an illustration of an exemplary pre-objective scanning system;

[0094] Figure 21 Shows Figure 23 the exemplary prism system of the pre-objective scanning system of;

[0095] Figure 22 Shows in relation to Figure 25 the exemplary scanning patterns associated with;

[0096] Figure 23 is an illustration of an exemplary pre-objective scanning system;

[0097] Figure 24 is an illustration of an exemplary pre-objective scanning system;

[0098] Figure 25 is a schematic diagram of a rotating objective lens scanning system;

[0099] Figure 26 schematically depicts a one-dimensional (1D) beam scanning system in accordance with some embodiments;

[0100] Figure 27 schematically depicts a two-dimensional (2D) beam scanning system in accordance with some embodiments; and

[0101] Figure 28 is a schematic diagram of a post-objective objective scanning system.

[0102] Note that the drawings are not necessarily to scale. The drawings are intended only to depict typical aspects of the subject matter disclosed herein and should not be regarded as limiting the scope of the present disclosure. The systems, devices, and methods specifically described herein and shown in the drawings are non-limiting exemplary embodiments. Detailed Description

[0103] Certain exemplary embodiments will now be described to provide a general understanding of the principles of the structure, function, manufacture, and use of the devices and methods disclosed herein. One or more examples of these embodiments are shown in the drawings. Those skilled in the art will understand that the devices and methods specifically described herein and shown in the 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 one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure.

[0104] Embodiments of the present disclosure are discussed in detail below in connection with fractionated treatments including skin rejuvenation and skin surface remodeling, such as skin surface remodeling for acne, chickenpox, and surgical scars, periorbital and perioral wrinkles, photoaging changes, facial pigmentary disorders, and stretch marks. Other treatments related to the present disclosure include the treatment of skin pigmentary disorders such as melasma and other pigmentary disorders such as granuloma annulare.

[0105] The disclosed embodiments can be used without limitation to treat other pigmentary and non-pigmentary conditions and other tissue and non-tissue targets. Examples of pigmentary conditions can include, but are not limited to, post-inflammatory hyperpigmentation (PIH), darkening of the skin around the eyes, dark eye circles, café-au-lait spots, Becker's nevi, nevus of Ota, congenital melanocytic nevi, lentigines (freckles), and ephelides. Other examples of pigmented tissues and structures that can be treated include, but are not limited to, hemosiderin-rich structures, pigmented gallstones, tattooed tissue, and structures rich in lutein, zeaxanthin, rhodopsin, carotenoids, biliverdin, bilirubin, and hemoglobin. Examples of targets for treating non-pigmented structures, tissues, and conditions can include, but are not limited to, hair follicles, hair shafts, vascular lesions, infectious conditions, sebaceous glands, acne, and the like.

[0106] Methods for treating various skin conditions (such as for cosmetic purposes) can be implemented using the systems described herein. It should be understood that although such methods can be performed by a doctor, non-doctors, such as cosmetologists and other appropriately trained personnel, can use the systems described herein to treat various skin conditions with or without the supervision of a doctor.

[0107] Furthermore, in the present disclosure, similarly named components of the embodiments generally have similar characteristics, and thus, in a particular embodiment, each characteristic of each similarly named component is not necessarily described in full detail. Additionally, in the description of the disclosed systems, devices, and methods where linear or circular dimensions are used, such dimensions are not intended to limit the types of shapes that can be used in conjunction with such systems, devices, and methods. Those skilled in the art will recognize that for any geometric shape, the equivalents of such linear and circular dimensions can be readily determined. The size and shape of the systems and devices and their components can depend at least on the anatomy of the subject on which the systems and devices will be used, the size and shape of the components on which the systems and devices will be used, and the methods and procedures in which the systems and devices will be used.

[0108] Generally, a high numerical aperture (NA) optical treatment system is described that can focus electromagnetic radiation (EMR) (e.g., a laser beam) onto a treatment area in tissue. The focused laser beam can deliver light energy to the treatment area without harming the surrounding tissue. The delivered light energy can, for example, treat tissue in a treatment area in the dermal layer of the skin without affecting the surrounding areas (e.g., the overlying epidermal layer, other parts of the dermal layer, etc.). In other embodiments, the delivered light energy can result in tattoo removal or alteration, or perform hemoglobin-related treatments.

[0109] Exemplary methods and apparatuses for treating skin diseases with light or light energy are disclosed in U.S. Patent Application Publication No. 2016 / 0199132, entitled "Method and Apparatus for Treating Dermal Melasma," and U.S. Provisional Application No. 62 / 438,818, entitled "Method and Apparatus for Selective Treatment of Dermal Melasma," the entire contents of which are incorporated herein by reference.

[0110] Generally, a system and corresponding method for treating skin diseases are provided. As discussed in more detail below, the disclosed system and method employ 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, and the focal region 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 otherwise damage portions of the tissue. In such a manner, the predetermined amount of energy can be delivered to any location within the target tissue for treatment, such as to improve its appearance.

[0111] Now referring Figure 1 to, a system 100 for radiotherapy 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 12000 nm, e.g., about 1550 nm). According to some embodiments, the EMR beam 112 has a transverse annular energy distribution (e.g., TEM01*) from the EMR source 110. According to other embodiments, a beam shaper 114 shapes the EMR beam to produce a transverse annular energy distribution. Figure 1A beam shaper 114 employing two axicons is shown. A first axicon 116 having a first wedge angle receives an EMR beam 112 and generates a Bessel beam 118. As the Bessel beam propagates, it forms a diverging annular energy distribution. The diverging annular energy distribution 120 is collimated by a second axicon 122 into a collimated EMR beam having a transverse annular energy distribution 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. The annular energy distribution 124 is then directed toward a focusing optical device 128. Some examples of the focusing optical device 128 include converging optics (e.g., plano-convex lenses) and axicons. The focusing optical device 128 converges the EMR beam and directs it toward tissue 130 (e.g., skin). In some cases, the focusing optical device converges the EMR beam with a numerical aperture (NA) of at least about 0.2 (e.g., about 0.3 to about 0.5). According to some embodiments, a window assembly 132 is located between the focusing optical device 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 is used to cool the tissue 130 during treatment. Generally, during operation of the device 100, the window assembly 132 is placed in contact with the outer surface of the tissue. According to some embodiments, the window assembly 132 includes two windows, a first window 134 and a second window 136, and a coolant chamber 138 is located between the two windows. The coolant chamber is configured to hold a coolant. In some embodiments, a coolant flow 140 flows through the coolant chamber 138. In some embodiments, the coolant includes one or more of the following: a dielectric fluid, a fluorocarbon-based fluid, ethylene glycol, propylene glycol, water, and an antifreeze. In most cases, the coolant is selected to be generally transmissive (e.g., greater than about 50%) 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 fluorocarbon-based fluid (e.g., Flourinert from 3M TM) The coolant is substantially transmissive at 1550 nm. In some embodiments, the medium 142 is placed between the bottom surface of the window assembly 132 and the outer surface of the tissue 130. In some versions, this medium 142 is used to match the refractive index of the window assembly 132 with that of the tissue 130. In some other versions, 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 with a refractive index approximately equal to that of the skin (e.g., approximately 1.4). In some embodiments, the system 100 further includes a controller 150 to control the EMR source 110. For example, in some embodiments, it is advantageous to control the EMR source 110 in response to the cooling of the tissue to ensure 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 determined 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 cools for a predetermined time 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 tissue temperature. Alternatively, the temperature of a component in thermal communication with the tissue is measured with a temperature sensor. For example, the temperature of the coolant when it flows out of the coolant chamber 138 can be used as an indicator of the tissue temperature.

[0112] In some embodiments, the controller 150 in communication with one or more of the EMR source 110, the beam shaper 114, and the focusing optics 128 is further configured to control one or more parameters of the EMR beam. Exemplary EMR beam parameters include the inner diameter of the annular energy distribution, the outer diameter of the annular energy distribution, the thickness of the annular energy distribution, and the depth of the focal region within the tissue. According to some embodiments, the EMR beam scans through the entire skin tissue to create multiple thermally damaged locations within the tissue, such as to provide fractionated treatment. Examples of systems and methods related to scanning high-NA EMR beams are disclosed in 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 Systems for EMR-Based Tissue Treatment," which are incorporated herein by reference.

[0113] Reference Figure 2, Flowchart 200 represents a method for irradiating tissue according to some embodiments. First, a window assembly is used to cool tissue 210, which is placed 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, and a cooling chamber is located between the two windows. The cooling chamber is configured to accommodate a coolant. In some embodiments, a coolant flow passes through the coolant chamber. In some embodiments, the tissue is cooled to a predetermined temperature before any subsequent step of method 200. In some embodiments, the tissue is cooled for a predetermined time before any subsequent step. In some cases, cooling the tissue to a predetermined temperature and for a predetermined time can prevent thermal damage to the outer layer of the tissue (e.g., the epidermis) and thereby reduce down time.

[0114] 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 directly senses the tissue temperature in some cases, while in other cases senses the temperature of another material associated with the tissue temperature (e.g., a coolant flowing out of a contact-type cooling assembly in contact with the tissue).

[0115] Next, an electromagnetic radiation (EMR) beam 220 is generated. The EMR beam includes a transverse annular energy distribution (e.g., TEM01* or an annular energy distribution). The EMR beam is then focused 230 to form a focal region. Generally, one or more optical devices (e.g., a focusing lens and / or an axicon) are used to focus the EMR beam. In some versions, the EMR beam is focused with a numerical aperture (NA) of about 0.2 or greater. Finally, the EMR beam is directed towards the tissue 240 such that the focal region is at least partially within the tissue (i.e., beneath the outer surface of the tissue). In some versions, directing the EMR towards the tissue 240 further includes scanning the EMR beam such that the focal region moves within the tissue. Scanning the EMR is generally done along at least one of three axes (e.g., two axes perpendicular to the optical axis and one axis parallel to the optical axis). For example, the focal region can be scanned laterally in the tissue, or scanned in depth 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 tissue surface between the tissue and the window assembly. In some embodiments, method 200 further includes controlling at least one parameter of the EMR beam. Exemplary parameters of the EMR beam include the inner diameter of the annular energy distribution, the outer diameter of the annular energy distribution, the thickness of the annular energy distribution, and the depth of the focal region within the tissue.

[0116] Exemplary embodiments

[0117] Now refer to Figure 3A , which shows an example system 300 with the front cover removed. The fiber laser source 310 outputs laser light. An example fiber laser source 310 is a CW Er-Yb laser with an average power of 20 W (e.g., IPG part number ELR-20-1550-LP from IPG Photonics in Oxford, Massachusetts). The collimator 312 collimates the laser light into a beam with a diameter of approximately 4 mm. Then, the collimated laser beam is shaped by the beam shaper 314 into a transverse annular (i.e., doughnut) energy distribution (e.g., TEM01*). Then, the laser beam is guided along the optical system and finally focused and guided out through the window assembly 316 on the bottom surface of the example system 300.

[0118] Figure 3B Shows an example system 300 and a cross-sectional view of the beam shaper 314 taken along the Figure 3A section line B-B in Figure 3B . In 2 , the beam shaper includes two identical axicons, a first axicon 320 and a second axicon 322. An example axicon is Thorlabs part number AX2510-C, which has a physical wedge angle of 10°. A laser beam with a near single-order mode (i.e., Gaussian transverse energy distribution and M Figure 3C Shows an example system 300 and the window 316 along Figure 3ACross-sectional view of the cross-section line C-C in. The focusing optical device 330 is located at the upper beam of the window 316 so that the laser beam converges as it passes through the window assembly 316. Eventually, the focusing optical device 330 brings the laser beam to a focusing area outside the window assembly 316 so that when the window assembly is placed in contact with the tissue, the focusing area is within the tissue. An exemplary focusing optical device is an aspherical lens, Thorlabs part number A240-C with a nominal effective focal length of 8 mm. In some embodiments, the Z stage 331 houses the focusing optical device 330 and is configured to adjust the position of the focusing optical device 330 along the optical axis and thereby affect the depth of the focusing area relative to the window 316 (i.e., the depth of the focusing area within the tissue). An exemplary Z stage 331 is Newscale PN: M3-FS from Newscale Technologies in Victor, New York. In some cases, the controller 150 is configured to control the Z stage to affect changes in the depth of the focusing area.

[0119] Figure 3D Shows an example taken from Figure 3C A detailed view of the exemplary system 300 of the detail circle D in. In Figure 3D The window assembly 316 is shown in more detail. The first window 340 is shown close to the focusing optical device 330. The second window 342 is shown separated from the first window 340. The coolant chamber 344 is located between the first window 340 and the second window 342. The coolant chamber 344 is hermetically sealed to contain the coolant as the coolant flows through the coolant chamber 344. The coolant is heated by contact with the window assembly 316 and returns to the cooler. The coolant is then cooled by the cooler, such as a thermoelectric cooler (e.g., solid-state cooled part number UC190 from Wappingers Falls, New York), and recirculated to the window assembly 316. The disclosure related to 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. Refer to Figures 3A to 3D The exemplary window assembly disclosed will be described in more detail below.

[0120] In Figures 3E to 3H Different views of the exemplary window assembly 316 for cooling during irradiation are schematically shown. Figure 3E A top perspective view of the assembly 316 is shown (i.e., the part of the cooling element 316 facing the EMR source / away from the target tissue). Figure 3F A bottom perspective view of the window assembly 316 is shown (i.e., the part of the window assembly 316 facing the target tissue / away from the EMR source). Figure 3GA bottom view of window assembly 316 is shown. Figure 3H A cross-sectional view of window assembly 316 taken along the Figure 3G section lines shown in is shown. Exemplary window assembly 316 includes a frame 350. Referring Figure 3E and Figure 3G , frame 350 has three fiducials 352. The fiducials 352 correspond to mounts on an energy-based device (such as 300) that can generate radiation, thereby allowing window assembly 316 to be removably attached and replaced on the energy-based device. According to some embodiments, the fiducials 352 can approximate one or more geometric forms, such as planes, lines, and points. According to some versions, the fiducials 352 include a part of a kinematic mount (e.g., a Maxwell or Kelvin mount). The three fiducials 352 of window assembly 316 can be located in a plane. Exemplary window assembly 316 further includes a first window 340 sealed to frame 350 by a first seal 354 and a second window 342 sealed to 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 welding, brazing, or soldering 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 permits this type of seal. Additionally, the second window 342 is secured to frame 350 with one or more fasteners 358. As can be seen from Figure 3G and Figure 3H , the fasteners 358 of window assembly 316 include splints that are held in place by three machine screws. Additional examples of fasteners can include screws, clamps, latches, retaining rings, tabs, or any combination thereof. Securing the second window 342 to the frame allows the distal surface 360 of the second window 342 to be firmly placed in contact with tissue without introducing additional stress to the second seal 356 that could cause bending or movement of the distal surface 360 of the second window 342.

[0121] Variations in the distance between the distal surface 360 and the optics that focus the EMR beam can affect the working distance of the beam and the location of the final focus within the tissue. According to some embodiments, the distal surface 360 of the second window 342 can be located at a predetermined geometry (e.g., orientation, position, etc.) relative to the datum 352. For example, in some versions, the second window 342 is positioned parallel to the plane approximated by one or more datums 352 within a desired tolerance (e.g., 0.5 mrad). Additionally, the second window 342 can be located 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 specified distance between them can be within a desired tolerance range (e.g., 0.5 mrad and 0.05 mm). For various reasons, in some embodiments, the distal surface 360 of the second window includes a non-planar shape (e.g., convex or concave). For example, a convex distal surface 360 can facilitate compression of the tissue when placed in contact with the tissue.

[0122] Figure 3H A chamber 344 within the system 400 is depicted. The chamber 344 is defined by the frame 350, the first window 340, and the second window 342. The chamber 344 can be sealed by a first seal 354 and a second seal 356. The chamber 344 is configured to contain a coolant. According to some embodiments, coolant is supplied to the chamber 344 through one or more ports 362 that are in fluid communication with the chamber 344. According to some embodiments, the port 362 can provide a coolant flow from a coolant flow source that is in fluid communication with the port 362. In some implementations, the coolant flow source can be in fluid communication with the port 362 through one or more fittings 364. Figure 3E and Figure 3F Both a coolant supply fitting 364a and a coolant return fitting 364b are shown for supplying coolant to and returning coolant from the chamber 344.

[0123] According to some embodiments, the second window includes a material having a high heat jet rate (e.g., quartz, sapphire, diamond, etc.). A higher heat jet rate may allow more heat to be transferred from the tissue surface to the coolant flow. Similarly, according to some embodiments, the first window 340 includes a material having a lower heat jet rate (e.g., glass or polymer). Embodiments with the first window 340 including a material with a lower heat jet rate may transfer less heat through the first window and into the coolant flow. Thus, condensation may occur more slowly compared to versions where the first window 340 includes a material with a high heat jet rate. Additionally, in some embodiments, the thickness of the first window (e.g., about 1 mm) is greater than the thickness of the second window (e.g., about 0.5 mm), allowing heat energy transfer to occur more freely through the second window. According to some versions, a non-condensing gas such as clean dry air, nitrogen, carbon dioxide, or argon may be blown towards the first window to further prevent condensation.

[0124] Figure 4A A simulated optical layout 400 according to some embodiments is shown. A collimated Gaussian beam 410 is incident and propagates convergently to a first axicon 412, and the collimated Gaussian beam forms a Bessel beam 414. The Bessel beam 414 is incident and propagates convergently to a second axicon 416, and the second axicon 416 forms a collimated transverse annular (i.e., toroidal) energy distribution beam 418. The collimated transverse annular energy distribution beam 418 is incident and propagates convergently to an aspherical focusing optical device 420, which forms a converging transverse energy distribution 422 focused to a focal region 424.

[0125] Figure 4B A first simulated Gaussian beam distribution 430 of the collimated Gaussian beam 410 is shown. Figure 4C A first simulated transverse annular (i.e., toroidal) beam distribution 432 of the converging transverse annular energy distribution 422 at 0.5 mm in front of the focal region 424 is shown. Figure 4D A second simulated transverse annular beam distribution 434 of the converging transverse annular energy distribution 422 at 0.2 mm in front of the focal region 424 is shown. And, Figure 4E A third simulated transverse annular beam distribution 436 of the converging transverse annular energy distribution 422 at 0.1 mm in front of the focal region 424 is shown. The converging transverse annular energy distribution beam 422 has a lower radiance in the beam distribution than a Gaussian mode beam under the same conditions. Referring Figure 4F , a Gaussian energy distribution 440 of the Gaussian beam at 0.5 mm from the focus is shown. Figure 4G A transverse annular (i.e., toroidal) energy distribution 442 of the transverse annular energy distribution beam at 0.5 mm from the focus is shown. Figure 4F and Figure 4GThe two light beams characterized therein have the same power (e.g., 1 W). However, the local maximum radiance of the Gaussian beam (e.g., 1.29 W / cm 2 ) is much larger than that of the beam with a transverse annular energy distribution (e.g., 0.75 W / cm 2 ). This allows the transverse annular beam to deliver a smaller peak energy density to the outer layer of the skin (e.g., the epidermis), while delivering the same amount of energy to the deeper layer of the skin (e.g., the dermis). The reduction of the peak local energy density in the transverse annular beam is controlled by changing the inner diameter width of the transverse annular energy distribution. A larger inner diameter pushes more energy to the outside of the beam and reduces the peak energy density (or power density) within the beam. In addition, by increasing the numerical aperture of the focusing optics 420, the peak local energy density in both the Gaussian and transverse annular energy distributions can be reduced.

[0126] Exemplary ex vivo studies

[0127] A number of studies were performed according to some embodiments. The studies were performed using a continuous wave (CW) erbium ytterbium fiber laser with a maximum average power of 20 W and a wavelength of 1550 nm (IPG laser model: ELR-20-1550LP). The excised human tissue was irradiated using a high numerical aperture (e.g., NA greater than or equal to 0.4) focusing system. Fractionated irradiation was accomplished by pulsing the CW fiber laser while the human tissue was scanned relative to the focusing system on an X-Y translation stage. The human tissue was then sectioned, stained, and examined. The nitroblue tetrazolium chloride (NBTC) stain was used to test viability. Specifically, the NBTC stain acts on proteins within the tissue. Once these proteins are damaged (e.g., heat denatured), they are no longer stained by NBTC and appear unstained.

[0128] Study No. 1

[0129] The first study was conducted to determine the pulse energy required for non-ablative thermal destruction of tissue using a Gaussian beam. The parameters used in Study No. 1 are shown below:

[0130] Table 1 - Parameters of Study No. 1

[0131]

[0132]

[0133] Figures 5A to 5D The tissue sections in show some representative results of Study No. 1. Figure 5A The horizontal section after irradiation with a pulse of energy of approximately 10 mJ is shown. Figure 5BShows a vertical cross-section after irradiation with a pulse of approximately 10 mJ of energy. NBTC staining demonstrated very slight thermal denaturation of the protein. In contrast, irradiation with pulse energies above 10 mJ, such as approximately 40 mJ, showed significant thermal damage. Figure 5C Shows a horizontal cross-section taken approximately 300 microns below the tissue surface after irradiation with each 40 mJ pulse. And, Figure 5D Shows a vertical cross-section of the tissue after irradiation with each 40 mJ pulse. The conclusion drawn from Study No. 1 was that, given this set of parameters, 10 mJ per pulse was the threshold pulse energy below which little or no thermal damage occurred.

[0134] Study No. 2

[0135] Study No. 2 was conducted to determine the effect of optically tissue-clearing media on fractionated non-ablative ex vivo irradiation. Prior to irradiation, excised human tissue samples were placed in the optically tissue-clearing media for 4 hours. The samples were immersed in a Petri dish containing the culture medium with the epidermis facing down. Two optically tissue-clearing media were tested: phosphate-buffered saline (PBS) and glycerol. The parameters used in Study No. 2 are shown below:

[0136] Table 2 - Parameters of Study No. 2

[0137]

[0138]

[0139] In the tissue samples immersed in the optically tissue-clearing media, thermal damage was visible only at 20 mJ per pulse. At the lower test pulse energies (5 mJ, 7 mJ, and 10 mJ), no obvious thermal damage was observed via NBTC viability staining. Some representative results of Study No. 2 are shown in Figure 6A the tissue sections up to Figure B. Figure 6A Shows a vertical cross-section of glycerol-immersed tissue irradiated with a 20 mJ pulse. Figure 6B Shows a vertical cross-section of PBS-immersed tissue irradiated with a 20 mJ pulse.

[0140] Study No. 3

[0141] Study No. 2 was conducted to determine the effect of a transverse annular (i.e., circular ring) energy distribution on fractionated non-ablative ex vivo irradiation. Prior to irradiation, excised human tissue samples were placed in the optically tissue-clearing media for 4 hours. The samples were immersed in a Petri dish containing the culture medium with the epidermis facing down. Two optically tissue-clearing media were tested: phosphate-buffered saline (PBS) and glycerol. The laser beam was shaped into the transverse annular energy distribution as described above and focused into the tissue. The parameters used in Study No. 2 are shown below:

[0142] Table 3 - Research Parameter No. 3

[0143]

[0144]

[0145] Reference Figures 7A to 7E Describes the histological results from Research No. 3. Figure 7A Shows four histological images in a Cartesian layout, with glycerol - soaked tissue on top, PBS - soaked tissue on the bottom, 10 mJ per pulse energy on the left, and 20 mJ per pulse energy on the right. Generally, the thermal damage at 20 mJ is significantly wider and deeper than that at 10 mJ pulse energy. Figure 7B Shows a horizontal histological image of tissue soaked in glycerol and irradiated with 10 mJ pulse energy. Figure 7C Shows a horizontal histological image of tissue soaked in glycerol and irradiated with 20 mJ pulse energy. Figure 7D Shows a horizontal histological image of tissue soaked in PBS and irradiated with 10 mJ pulse energy. Figure 7E Shows a horizontal histological image of tissue soaked in PBS and irradiated with 20 mJ pulse energy. In the horizontal histology of tissue irradiated with a transverse annular energy distribution, annular damage can be seen (e.g., Figure 7C ). The damage that appears annular in horizontal histology is a three - dimensional thin - walled hollow damage cone that reaches a point at a certain depth (e.g., 300 microns to 1000 microns) within the tissue. Inside the damage cone, there is healthy unaffected tissue, as shown by the annular damage in the horizontal section (e.g., Figure 7C ) and the "Y" - shaped damage in the vertical section (e.g., Figure 7A ). One advantage of this irradiation pattern is that there is less epidermal damage compared to current fractionated irradiation techniques; and, the damaged epidermis is damaged in a small and narrow width (e.g., 1 - 100 microns) surrounded by healthy (i.e., unaffected) tissue.

[0146] Parameter Selection

[0147] The following table outlines the parameters relevant to the practice of the embodiments of the present disclosure:

[0148] Table 4 - Exemplary Parameters and Ranges

[0149]

[0150]

[0151] In some embodiments, aspects of the annular energy distribution are controllable. Figure 8Shown is a pair of axicon lenses 800 configured to produce an annular energy distribution. The relationship between the separation (S) 810 of the two axicon lenses 800 and the large diameter 812 of the resulting annular beam can be expressed as:

[0152]

[0153] where n is the refractive index of the first and second axicon lenses, and α is the wedge angle of the first and second axicon lenses 800.

[0154] As described above, when entering the axicon lens pair 800, the collimated beam diameter 814 determines the width 816 of the annular energy distribution. Thus, in some embodiments, the width of the annular energy distribution 816 is controlled by changing the collimated beam diameter 814. For example, in some cases, a beam expander (e.g., a Gallian beam expander or a Keplerian beam expander) is used to expand (or reduce) the collimated beam diameter 814 before the collimated beam diameter 814 reaches the axicon lens pair 800. The small (i.e., inner) diameter 818 can be expressed in terms of the large (i.e., outer) diameter 812 of the annular energy distribution. Specifically, the small diameter 818 is equal to the large diameter 812 minus the diameter of the collimated beam 814, or:

[0155]

[0156] where, is the small diameter 818; is the large diameter 812; and is the beam diameter 814. According to some embodiments, one or more parameters associated with the annular energy distribution are controlled by a controller that manipulates the above parameters (e.g., the axicon lens pair 800 separation distance 810 and / or the beam expander rate). For example, in some cases, the separation distance 810 between the axicon lens pair 800 can be electronically manipulated by using a motorized stage (e.g., Thorlabs PN: PT1-Z8). Similarly, in some cases (e.g., a Gallian beam expander), the optical path distance between two optical devices controls the beam expansion (or beam reduction) rate of the beam expander. In this case, when the beam 814 enters the axicon lens pair 800, the motorized stage can also be used to control the width of the beam 814.

[0157] Small-diameter fractionated treatment results in smaller damage and faster healing. For example, it has been found that fractionated lesions greater than a specific width (e.g., about 0.15 mm, 0.25 mm, or 0.5 mm) can cause scarring in some individuals. Even small fractionated lesion widths below the smallest achievable commercially, down to the threshold minimum fractionated lesion width size, will further minimize downtime. Specifically, a beam size smaller than a single cell (e.g., about 20 microns) results in a virtually minimal possible fractionated lesion. As described above, in some cases, the above-described exemplary optical system causes thermal damage to tissue at this scale. In additional exemplary embodiments, small fractionated lesions to this tissue are achieved by another exemplary optical system.

[0158] Based on the above embodiments, those skilled in the art will understand further features and advantages. Thus, except as pointed out in the appended claims, the disclosed embodiments are not limited by what has been specifically shown and described herein. All publications and references cited herein are hereby expressly incorporated by reference in their entirety.

[0159] Additional embodiments.

[0160] Reference Figures 9A to 9B Another embodiment is described that affects fractionated lesions on the order of tens of microns. Reference Figure 9A , shows an optical scheme 900 that produces a Bessel beam focusing region 910. Different from a typical diffraction-limited focusing region, the Bessel beam focusing region has a focusing width and a focusing region length that can be decoupled from each other. Generally, the focusing region length (i.e., the depth of field) is proportionally related to the square of the radius of the focusing region (e.g., the Rayleigh range). Separating the focusing region length from the focusing region width allows for the formation of a very long (e.g., greater than 0.5 mm long) and very narrow (e.g., less than about 0.1 mm wide) focusing region.

[0161] Figure 9A Schematically shows an optical path that can be used to produce 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 onto the Bessel beam focusing region 910.

[0162] According to some exemplary embodiments, the damage width of fractionated treatment is related to the width of the first lobe of the Bessel beam focusing region 910. The half-width ω0 of the first lobe of the Bessel beam focusing region 910 is a function of the wavelength λ, the wedge angle α of the axicon, and the refractive index n of the axicon:

[0163]

[0164] Thus, according to some embodiments, this selection of the optical parameter is achieved by selecting the axicon wedge angle of the third axicon lens 918. The following table illustrates some exemplary first lobe diameters of the 1550 nm beam based on the axicon wedge angle.

[0165] Table 5 - Wedge Angle to First Lobe Diameter (Wavelength = 1550 nm)

[0166]

[0167] The damage length of the fractional treatment is related to the length of the Bessel beam focusing region 910. The length of the Bessel beam formed by the axicon lens (e.g., depth of field [DOF]) 920 is a function of the beam width at the axicon lens. When using an annular beam, the focusing region length is a function of the annular width 922. The width of the annulus is in turn a function of the width of the collimated beam 924 (e.g., half of it), and the collimated beam 924 is shaped to form the annular beam. The length of the Bessel beam can be approximately calculated by the following formula:

[0168]

[0169] For example, for an output beam of 4 mm, a wavelength of 1550 nm, and a wedge angle of 20°, the length of the Bessel beam focusing region is close to 15 mm.

[0170] The working distance (WD) 926 between the end of the third focusing axicon lens 918 and the Bessel beam focusing region 910 is a function of the inner diameter 928 of the ring 916. Referring to Figures 9A to 9B , the working distance 926 measured from the end of the axicon lens 918 can be approximately calculated using the following equation:

[0171]

[0172] The above equation is derived from the following two equations for X1 and X0. Figure 9B Illustrates the relationship between these equations.

[0173] X0 = -r * tan(α)

[0174]

[0175] WD = X0 + X1

[0176] As can be seen above, the small (i.e., inner) diameter 928 of the annular energy distribution 916 affects the working distance 926. For example, a non-annular beam acted upon by an axicon results in a Bessel beam focusing region starting from the end of the axicon. In some embodiments, by controlling the small diameter 928 of the annular beam incident on the focusing axicon 918 and thereby affecting the working distance 926 of the focusing region 910, the focusing region 910 is controlled at a depth within the tissue (e.g., beneath the tissue surface). In some versions, the small diameter 928 of the annular beam 916 is a function of the spacing between the first axicon 912 and the second axicon. The small diameter can be represented by the large (i.e., outer) diameter 930 of the annular energy distribution 916. Specifically, the small diameter 928 is equal to the large diameter 930 minus the diameter of the collimated beam 924, or:

[0177]

[0178] Figure 10 An exemplary embodiment of a treatment system 1010 is shown. As shown in the figure, the treatment system 1010 includes a platform 1012, a transmitter 1014, and a controller 1016. The platform 1012 may include one or more manipulators or arms 1020. The arm 1020 may be coupled to the transmitter 1014 for performing various treatments on a target tissue 1022 of an object 1024. The operation of the platform 1012 and the transmitter 1014 can be directed manually by a user or using the controller 16 (e.g., via a user interface). In certain embodiments (not shown), the transmitter may 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 coupled to the controller for manipulating the transmitter.

[0179] The transmitter 1014 and the controller 1016 (and optionally the platform 1012) may communicate with each other via a communication link 1026, which may be any suitable type of wired and / or wireless communication link that carries any suitable type of signal (e.g., electrical, optical, infrared, etc.) according to any suitable communication protocol.

[0180] Embodiments of controller 1016 can be configured to control the operation of emitter 1014. In one aspect, controller 1016 can control the movement of EMR 1030. As discussed in detail below, emitter 1014 can include a source 1032 for emitting EMR 1030 and a scanning system 1034 for manipulating EMR 1030. As an example, scanning system 1034 can be configured to focus EMR 1030 onto a focal region and translate and / or rotate this focal region in space. Controller 1016 can send signals to source 1032 via communication link 1026 to command source 1032 to emit EMR 1030 having one or more selected characteristics, such as wavelength, power, repetition rate, pulse duration, pulse energy, focusing characteristics (e.g., focal volume, Rayleigh length, etc.). In another aspect, controller 1016 can send signals to scanning system 1034 via communication link 1026 to command scanning system 1034 to move the focal region of EMR 1030 relative to target tissue 1022 in one or more translation and / or rotation operations.

[0181] Embodiments of treatment system 1010 and method are discussed herein in the context of treating within skin tissue, such as the dermis layer. However, the disclosed embodiments can be used without limitation to treat any tissue at any location of a subject. Examples of non-skin tissue can include, but are not limited to, mucosal tissue, genital tissue, surface and subsurface regions of internal organ tissue, and gastrointestinal tissue.

[0182] Exemplary manual scanning system

[0183] In some embodiments, a handheld system 1100 is used, which is manually scanned (i.e., manually moved by a clinician) over the treatment area. Figures 11A to 11C An exemplary embodiment that can be manually scanned is shown. Figure 11A A front view of system 1100 is shown; Figure 11B A side view of system 1100 is shown; and, Figure 11C A cross-sectional view of system 1100 is shown. Referring Figures 11A to 11C , the fiber laser outputs a laser beam through collimator 1110. The laser beam can be of any wavelength. Details of wavelength selection were described in detail above. Beam shaper 1112 acts on the collimated laser beam. As described in detail above, beam shaper 1112 receives the collimated laser beam from collimator 1110 and shapes it into a transverse annular energy distribution. As shown in the cross-sectional view ( Figure 11C) As shown, 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 central misalignment). After the beam shaper 1112, the laser beam is then reflected by the 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 beam expander optics are dynamic and can be moved 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 of Victor, New York. The beam expander 1116 expands the collimated annular beam by a factor between 2 and 20, for example. When leaving the beam expander 1116, the laser beam is reflected by a static folding mirror 1118, focused by an objective lens 1119 (e.g., an aspherical focusing optic, e.g., an aspherical lens PN: AFL25-40 from Jena, Germany), reflected by a second galvanometer mirror 1120, and directed out through a contact window 1122. In some versions, the beam expander is a afocal relay system that is placed at the conjugate distance between the first galvanometer mirror 114 and the objective lens 1119. The contact window 1122, like many of the windows described in detail above, includes a first window 1122A; a second window that is separated from the first window 1122B; 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 cases because it helps ensure positive contact with the tissue being treated and makes it easier to slide off the tissue.

[0184] Figures 11A to 11C The handheld system 1100 described in is used to manually treat an area. As the clinician moves the handheld system 1100 over the tissue being treated, the second galvanometer mirror 1120 scans rows of points on the skin surface from side to side. Now referring to Figure 12 , an exemplary row of scanned points 1200 is shown. The exemplary row 1200 includes eight individual points 1210 at which laser energy is delivered. As Figure 12As shown, eight points 1210 are scanned in sequence from top to bottom (i.e., A - H). After the last point (i.e., point H) is delivered energy, the line scan is repeated and starts again. The width 1212 of the line is approximately equal to the number of points 1210 multiplied by the pitch 1214 (i.e., the distance between adjacent points). Referring briefly again to Figures 11A to 11C , the second galvanometer mirror 1120 of the handheld system 1100 scans the line along the manual scan direction 1216, which is generally perpendicular to the direction of the line scan 1200.

[0185] Exemplary Beam Scanning System

[0186] In some embodiments, a beam scanning system and method are provided. The disclosure related to these embodiments and the beam scanning system and method is described below. Generally, the beam scanning system and method can be classified as one or more of the following types: pre - objective scanning, objective scanning, and post - objective scanning. Pre - objective scanning includes embodiments in which the beam is scanned (e.g., deflected, tipped, and / or tilted) before being directed onto the objective (i.e., the beam on the objective). Objective scanning includes embodiments in which the beam is scanned (e.g., deflected, tipped, and / or tilted) at the objective, for example, by moving the objective. Post - objective scanning includes embodiments in which the scanning (e.g., deflected, tipped, and / or tilted) is performed after the objective (i.e., the beam under the objective).

[0187] Pre - objective Scanning

[0188] Figure 13 is a schematic diagram of a pre - objective scanning system 2100, which includes an objective 2110 and a scanning unit 2112. The scanning unit 2112 can receive a laser beam 2104 from a laser source 2102 and direct the laser beam 2104 onto the objective 2110. The objective 2110 can receive the laser beam 2104 and direct the focused laser beam 2106 to a focused 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 onto the objective 2110. For example, the scanning system 2112 can change the direction of the outgoing laser beam along one or more scanning directions. The change in the direction of the laser beam 2104 impinging on the objective 2110 can cause the focused volume 2108 to trace a treatment path 2114 in the tissue 2116. The focused volume 2108 traverses the treatment path 2114 at a scanning rate. 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) onto the objective 2110. The pre - objective scanning system 2100 can include a contact surface (e.g., as Figure 24As shown in [figure reference], the contact surface can be positioned between the objective lens 2110 and the tissue 2116. The contact surface can apply pressure to the surface of the tissue 2116 and allow heat to dissipate from the surface of the tissue 2116.

[0189] Figure 14 is a diagram of an exemplary forward scanning system 2200 for an objective lens. The scanning system 2200 includes a polygon scanner 2202 that can receive an incident laser beam 2104 (e.g., from a laser source 2102) and direct the incident laser beam 2104 towards the objective lens 2110 (e.g., an f-θ lens). The exit direction of the laser beam 2104 (e.g., the angle of incidence at which the laser beam 2104 strikes the objective lens 2110) can determine the position of the focused volume 2108 in the tissue 2116 (e.g., in the x-y plane). According to some embodiments, the laser source 2102 provides a plurality of laser pulses, and the plurality of laser pulses result in a plurality of corresponding focused volumes. The distance between two focused volumes caused by consecutive laser pulses is the focused volume pitch.

[0190] The polygon scanner 2202 can include a plurality of reflective surfaces (e.g., 2202a-c). The polygon scanner 2202 can rotate about an axis 2204 along a rotation direction 2206. As the reflective surfaces 2202a-c rotate about the axis 2204 (e.g., the angular position of the reflective surfaces 2202a-c relative to the axis 2204 changes), the angle of incidence of the incident laser beam 2104 in the y-z plane changes. This changes the direction of the exit laser beam 2104 along a first scanning direction (e.g., along the y-axis). For example, if the reflective surface (e.g., 2202b) rotates about the axis 2204 along the rotation direction 2206, the direction of the exit laser beam sweeps from a higher y value to a lower y value.

[0191] The axis 2204 can be tilted / rotated about the z-axis and / or the x-axis. This can cause the angle of incidence of the incident laser beam 2104 in the x-z plane to change, which changes the direction of the exit laser beam 2104 along a second scanning direction (e.g., along the x-axis). The rotation of the polygon scanner 2202 and the rotation / tilt of the axis 2204 can allow the direction of the exit laser beam 2104 to be changed, which can result in scanning of the exit laser beam 2104 in the x-y plane.

[0192] Based on the change in the direction of the outgoing laser beam 2104, the objective lens 2110 can track the focal volume 2108 along one or more treatment paths in the tissue 2116. For example, a change in the direction of the outgoing laser beam 2104 due to the rotation of the polygon scanner 2202 can cause the focal volume 2108 to move along the y-axis. A change in the direction of the outgoing beam due to the tilt of the axis 2204 causes the focal volume 2108 to move along the x-axis. In one embodiment, the pre-objective scanning system 2200 can move along the x-axis relative to the tissue 2116. This can cause the position of the focal volume 2108 to be tracked along the x-axis.

[0193] The focal volume 2108 can also move along a third treatment path, i.e., along the z-axis. This can 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 optical path of the incoming 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 of the focal volume 2108 can be tracked along the z-axis (e.g., the depth of the tissue 2116).

[0194] Figure 15 The beam folding plane 2300 for the pre-objective scanning system 2200 is shown. By folding the scanning system 2200 around the beam folding plane 2300, the scanning system 2200 can be made compact (e.g., by reducing the extent of the scanning system 2200 along the z-axis). For example, this can be achieved by placing a mirror (e.g., a plane mirror) in the beam folding plane and orienting the mirror parallel to the x-y plane.

[0195] Figure 16 An exemplary f-θ lens 2400 that can be used as the objective lens in the pre-objective scanning system 2200 is shown. The incoming laser beam 2104 can impinge on the reflective surface 2402 (e.g., the reflective surface 2202b of the polygon scanner 2202), which can direct the outgoing laser beam 2104 to the f-θ lens 2400. The orientation of the reflective surface 2402 can determine the angle of incidence at which the outgoing laser beam 2104 impinges on the f-θ lens (e.g., the angle of incidence in the y-z plane). The angle of incidence can determine the position of the focal volume 2108 (e.g., along the y-axis).

[0196] Figure 17FIG. is an illustration of 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 towards an objective 2110 (e.g., an f - θ lens). The direction of the outgoing laser beam 2104c can determine the position of the focal volume 2108 in the tissue 2116 (e.g., in the x - y plane).

[0197] The mirror system can include two scanning mirrors. The first scanning mirror 2506 can rotate about a first axis 2522 (e.g., clockwise, counter - clockwise, etc.), and the second scanning mirror 2508 can rotate about a second axis 2524 (e.g., clockwise, counter - clockwise, etc.). As 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 outgoing laser beam 2104b along a first scanning direction (e.g., along the y - axis). As 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 outgoing 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 allow for changing the direction of the outgoing laser beam 2104c, which can result in scanning of the outgoing laser beam 2104c in the objective plane.

[0198] Based on the change in the direction of the outgoing laser beam 2104c, the objective 2110 can track the focal volume 2108 (not shown) along one or more treatment paths in the tissue 2116. For example, a change in the direction of the outgoing laser beam 2104c due to the 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 outgoing laser beam 2104c due to the rotation of the second scanning mirror 2508 can cause the focal volume 2108 to move along a second treatment path.

[0199] The scanning system 2500 can include a lens 2540 that can be placed in the optical path of the laser beam 2104a, 2104b, or 2104c. By changing the position of the lens 2540 along the direction of the beam propagation, the position of the focal volume 2108 can be tracked along the depth of the tissue 2116.

[0200] In some embodiments of the mirror system, the change in the direction of the first scanning mirror 2506 in the direction of the laser beam 2104b can be large. This can prevent the laser beam 2104b from hitting the second scanning mirror 2508. Additionally, a large angle of incidence of the laser beam 2104b on the second scanning mirror 2508 can result in a curved treatment path of the focal region. By including a third scanning mirror between the first scanning mirror 2506 and the second scanning mirror 2508, these effects can be prevented / reduced. Figure 18FIG. shows an exemplary pre - objective scanning system 2600 including a third scanning mirror 2507, which is located downstream of a first scanning mirror 2506 and upstream of a second scanning mirror 2508. The third scanning mirror 2507 can allow for a smaller second scanning mirror 2508 and can prevent / reduce the curvature of the treatment path of the focal region.

[0201] Figures 19A to 19C Illustrates various scanning patterns of an outgoing beam (e.g., outgoing laser beam 2104) from a scanning unit 2112 (e.g., polygon scanner 2202, mirror system 2502, etc.). Figure 19A Illustrates a first scanning pattern, in which the outgoing beam is scanned in the following order: (a) a movement from left to right (e.g., along the x - axis), (b) a movement from top to bottom (e.g., along the y - axis), and (c) a movement from right to left (e.g., along the negative x - axis). Figure 19B Illustrates a second scanning pattern, in which the outgoing beam is scanned in the following order: (a) a movement from left to right (e.g., along the x - axis), (b) a superposition of a movement from top to bottom and a movement from right to left, and (c) a movement from left to right. Figure 19C Illustrates a third scanning pattern, in which the outgoing beam is scanned in the following order: (a) a superposition of a movement from left to right and a movement from top to bottom, and (b) a superposition of a movement from right to left and a movement from top to bottom. The movement of the beam (e.g., from left to right, from right to left, from top to bottom, etc.) can be obtained by clockwise or counter - clockwise rotation of the scanning mirrors 2506, 2507, 2508, or by rotation / axis tilt of the polygon scanner 2202.

[0202] Figure 20 FIG. shows an exemplary pre - objective 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 outgoing beam 2105 to an objective 2110 (e.g., an f - θ lens) (see Figure 21 ). The direction of the outgoing beam 2105 can determine the position of the focal volume 2108 in the tissue 2116.

[0203] Figure 21Shows a prism system 2802 that can be used with an objective front scanning system 2800. The prism system 2802 includes a first prism 2806 and a second prism 2808, and the first prism and the second prism can rotate about a common axis 2822. Each of the prisms can change the direction of an incident light beam by a characteristic angle. If both the first prism 2806 and the second prism 2808 are perfectly aligned, the direction of the incident laser beam is changed by twice the characteristic angle. If the first prism 2806 and the second prism 2808 are completely misaligned, the direction of the incident laser beam remains unchanged. For all other orientations of the prisms 2806 and 2808, the direction of the incident laser beam can be changed by an angle that is within the range between zero degrees and twice the characteristic angle.

[0204] If both prisms 2806 and 2808 rotate at the same angular velocity (e.g., their relative orientation remains unchanged during rotation), the output beam 2105 scans along a circular treatment path. If prisms 2806 and 2808 rotate at different angular velocities, their relative orientation will change during rotation. For example, the prism pair will swing between a fully aligned state (the direction of the output beam is deviated by twice the characteristic angle) and a fully misaligned state (the direction of the output beam remains unchanged).

[0205] Figure 22 Shows the scanning pattern of the output beam 2105 caused by the prism system 2802, where the angular velocities of the first prism and the second prism are different. The output beam forms a spiral pattern - the output beam 2105 can spiral inward (e.g., until it reaches the center), and then can spiral outward.

[0206] Figure 23FIG. 0 is an illustration of an exemplary pre - objective scanning system 3100. The scanning system 3100 includes a scanning unit 3102 that is coupled to an optical fiber 3110 that can direct 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 end of the optical fiber near the objective 3112) about the x - axis. This changes the direction of the outgoing laser beam 2104 along a first scan direction (e.g., along the y - axis). The second actuator 3108 can rotate a portion of the optical fiber 3110 (e.g., the end of the optical fiber near the objective 3112) about the y - axis. This changes the direction of the outgoing laser beam 2104 along a second scan direction (e.g., along the x - axis). Actuation of the first actuator and the second actuator can allow for changing the direction of the outgoing laser beam 2104, which can result in scanning of the outgoing laser beam 2104 in the plane of the objective 3112 (e.g., the x - y plane). Based on the change in the direction of the outgoing laser beam 2104, the objective 3112 (e.g., an f - θ lens) can trace a focal volume 2108 along one or more treatment paths in the tissue 2116.

[0207] Figure 24 FIG. 4 is an illustration of an exemplary pre - objective scanning system 3200. The scanning system 3200 includes a scanning unit 3202 that is coupled to an optical fiber 3210 (e.g., rigidly coupled) that can direct 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 location 3230 on the six - axis actuator 3206. The support arm 3208 can support the portion of the optical fiber that is close to the tissue 2116.

[0208] The six - axis actuator 3206 can move the optical fiber 3210 along the x - axis, the y - axis, and the z - axis. Additionally or alternatively, the six - axis actuator 3206 can rotate the optical fiber 3210 about the x - axis, the y - axis, and the z - axis. The end of the optical fiber 3210 can be coupled to an objective 3212 that can focus the outgoing laser beam 2104 onto a focal volume 2108 in the tissue 2116. The pre - objective scanning system 3200 can further include a contact surface 3216 that can be located in the optical path of the outgoing laser beam 2104 between the objective 3212 and the tissue 2116.

[0209] The focused 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 focused 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 embodiments, it may be desirable to vary the distance between the end of the optical fiber 3210 and the tissue 2116 during rotation (e.g., along the x-axis, y-axis, etc.) (e.g., by moving the end of the optical fiber along the z-axis) to ensure that the focused volume 2108 remains at a fixed depth within the tissue 2116.

[0210] Objective lens scanning

[0211] Figure 25 is a schematic diagram of a rotating objective lens scanning system 3300. The rotating objective lens 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 focused area 3308 within a treatment area 3310 of tissue 3311 (e.g., skin). As the objective lens moves (e.g., relative to the scanning system 3300 and / or due to movement of the entire scanning system 3300), the focused area can trace a treatment path 3312 across the entire treatment area 3310. The treatment path 3312 can have a path geometry (e.g., circular, elliptical, etc.). The scanning system 3300 includes optical elements capable of directing the laser beam 3304 (or a portion of the laser beam 3304) towards the moving objective lens.

[0212] The scanning system 3300 may also include an interface (also referred to as a “base,” “window,” or “contact surface”) that can stabilize the treatment area 3310 and / or facilitate control and uniformity of radiation distribution. For example, the interface can fix the treatment area 3310 by applying pressure and / or by including a gel pad between the interface and the treatment area. The pressure applied by the interface on the treatment area 3310 can be detected by a pressure detector. The interface may also include a contact sensor that detects relative movement between the skin and the interface. The pressure provided by the interface on the treatment area can also blank out (or remove some blood from) the volume of the irradiated treatment area. This can result in selective absorption of the focused laser beam 3306 by the treatment area (e.g., pigmented cells within the treatment area), while reducing the risk of unwanted damage to blood vessels.

[0213] The interface can cool / dissipate heat from the treatment area 3310, which can be generated, for example, by heating of the treatment area 3310 due to the focused laser beam 3306. The interface can be made of a material suitable for heat dissipation (e.g., sapphire, diamond, glass, etc.). In some embodiments, 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. If the temperature exceeds the threshold temperature, the user can be notified and / or a cooling unit (e.g., a Peltier device, a cryogenic spray, a heat conducting tube, etc.) can be activated to cool the treatment area.

[0214] The rotating objective scanning system can have various embodiments. Two exemplary embodiments of the rotating objective scanning system include an in-plane rotating objective scanning system and a transverse rotating objective scanning system, both of which will be described below.

[0215] Figure 26 A system 3400 for scanning an electromagnetic radiation (EMR) beam 3402 is schematically depicted in accordance with some embodiments. A motor 3404 generates a rotational movement 3406. The motor 3404 is operatively coupled to a reciprocating mechanism 3408 such that the rotational movement 3406 drives the reciprocating mechanism 3408. The reciprocating mechanism 3408 converts the rotational movement 3406 into a reciprocating movement 3410 that generally acts linearly along a first scan axis 3412 (e.g., the x-axis). According to some embodiments, the reciprocating mechanism includes one or more of the following: a cam and follower, a crank and slider, a Scotch yoke, and a multi-link mechanism. According to some embodiments, the reciprocating movement 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 reciprocating movement 3410 with a constant speed. In other words, the reciprocating movement 3410 has a substantially flat speed profile over some portion of at least one stroke.

[0216] Embodiments of constant speed can employ a predetermined or desired constant speed. For example, the desired constant speed can be selected from a range of about 2 mm / s to about 5 m / s. In certain embodiments, the constant speed can be a selected percentage of the desired constant speed. As an example, the selected percentage can be selected from a range of about 10% to about 90% (e.g., about 50%) of the desired constant speed.

[0217] The stroke portion that provides the reciprocating movement 3410 with a constant speed can vary. For example, the stroke portion with a constant speed can be selected from a range of about 5% to about 95%. (e.g., at least about 10%).

[0218] The focusing optical device 3414 is operatively coupled to the reciprocating mechanism 3408 such that it undergoes a reciprocating movement 3410 and moves in accordance with the reciprocating movement. The focusing optical device 3414 is configured to focus the EMR beam 3402 along the optical axis 3418 to a focal point 3416. The reciprocating movement 3410 of the focusing optical device 3414 thus moves the focal point 3416 and the optical axis 3418 along a first scan axis 3412.

[0219] According to some embodiments, the EMR beam 3402 is generated by an electromagnetic radiation (EMR) source 3420. Examples of the EMR source are described in detail below. The EMR beam 3402 is transmitted from the EMR source 3420 and is guided by the optical system 3422 to be incident on the focusing optical device 3414. Generally, the optical system 3422 includes one or more reflective and / or transmissive optical devices. 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 placed along the optical axis 3418 is mechanically fixed to the focusing optical device 3414, thus undergoes the reciprocating movement 3410, and moves in accordance with the reciprocating movement 3410. As discussed in more detail below, the EMR source 3420 can 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 movement 3410 can determine the nominal spacing between consecutive pulsed foci along the first scan axis 3412.

[0220] According to some embodiments, the housing 3426 is disposed along the optical axis between the focusing optical device 3414 and the focal point 3416. The housing 3426 is configured to contact a target surface, such as the surface of the target tissue 3428, via a contact surface. As shown in the figure, the focal point 3416 is positioned below 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 can be configured to cool the target tissue 3428. In another embodiment, one or more sensors (e.g., pressure sensors, contact sensors, temperature sensors, etc.) can be located within the housing and are configured to measure one or more variables of the target tissue. The one or more variables can include at least one of pressure, contact between the contact surface and the target tissue, and temperature

[0221] 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 versions, the controller 3430 obtains inputs from one or more sensors 3432 that measure at least one of the rotational movement 3406 and the reciprocating movement 3410.

[0222] Figure 27Schematically depicts a system 3500 that scans an electromagnetic radiation (EMR) beam on two axes. A motor 3502 generates a rotational movement 3504 and delivers it to a reciprocating mechanism 3506, which converts the rotational movement 3504 into a reciprocating movement 3508 along a first scan axis 3510. According to some embodiments, the reciprocating movement 3508 includes a linear stroke and has a constant speed over a portion of the linear stroke. A focusing optical device 3512 is mechanically fixed to the output of the reciprocating mechanism 3506 such that it undergoes the reciprocating movement 3508 and moves in accordance with the reciprocating movement 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 the following: a ratchet mechanism, an intermittent work wheel mechanism, a cam mechanism, and an intermittent gear mechanism. According to some embodiments, the intermittent movement 3516 is linear and generally acts along a second scan axis 3518, which is generally orthogonal to the first scan axis 3510.

[0223] According to some embodiments, the intermittent mechanism 3514 is configured to introduce the intermittent movement 3516 when the reciprocating movement 3508 is at or near a particular position, such as at the start of the stroke, in the middle of the stroke, or at the end of the stroke.

[0224] 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 versions, the controller 3530 obtains inputs from one or more sensors 3532, which measure at least one of the rotational movement 3504, the reciprocating movement 3508, and the intermittent movement 3516.

[0225] Post-objective scanning

[0226] Figure 28 is a schematic diagram of a post-objective scanning system 3600. The post-objective scanning system 3600 includes an objective 3610 and a scanning unit 3612. The objective 3610 can receive a laser beam 3604 from a laser source 3602 and direct a focused laser beam 3606 to the scanning unit 3612. The scanning unit 3612 can receive the focused laser beam 3606 and direct it to a focused area 3608 in a treatment area of tissue 3616 (e.g., skin). The scanning unit 3612 can allow the focused area 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) toward the skin.

[0227] Example parameters according to some embodiments of pre-objective and post-objective beam scanners are disclosed in the following table:

[0228] Example scanning parameters

[0229]

[0230] The subject matter described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structural devices and their structural equivalents disclosed in this specification, or combinations thereof. The subject matter described in this specification can be implemented as one or more computer program products, e.g., one or more computer programs tangibly embodied in an information carrier (e.g., in a machine-readable storage device) or included in a propagated signal, for execution by, or to control the operation of, data processing apparatus (e.g., a programmable processor, a computer, or multiple computers). A computer program (also referred to as a program, software, software application, or code) can be written in any form of programming language, including a compiled or interpreted language, and it can be deployed 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 does not necessarily 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 being discussed, or in multiple cooperating files (e.g., files that store one or more modules, subroutines, or portions of code). A computer program can be deployed to be executed on one computer or multiple computers at one location, or distributed across multiple locations and interconnected by a communication network.

[0231] The processes and logical flows described in this specification, including the method steps of the subject matter described in this specification, can be performed by one or more programmable processors executing one or more computer programs to perform the functions of the subject matter described in this specification by operating on input data and generating output. The processes and logical flows can also be performed by dedicated logic circuitry, and the apparatus of the subject matter described in this specification can be implemented as dedicated logic circuitry, e.g., an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0232] For example, processors suitable for executing computer programs include both general and special purpose microprocessors, as well as any one or more processors of any kind of digital computer. In general, a processor will receive instructions and data from a read only memory or a random access memory or both. The basic elements of a computer are a processor for executing the instructions and one or more memory devices for storing the instructions and data. In general, a computer will also include or be operatively coupled to one or more mass storage devices (such as magnetic disks, magneto-optical disks, or optical disks) for storing data, to receive data from or transfer data to the mass storage device, or both. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including, for example, semiconductor memory devices (such as EPROM, EEPROM, and flash memory devices); magnetic disks (such as internal hard disks or removable disks); magneto-optical disks; and optical disks (such as CD and DVD disks). The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0233] To provide for interaction with a user, the subject matter described herein can be implemented on a computer having a display device (such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user, and a keyboard and a pointing device (such as a mouse or a trackball) by which the user can provide input to the computer. Other types of devices can also be used to provide for interaction with the user. For example, feedback provided to the user can be any form of sensory feedback (such as, visual feedback, auditory feedback, or tactile feedback), and input received from the user can be in any form, including auditory input, speech input, or tactile input.

[0234] The techniques described herein can 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 construed as software that is not implemented on hardware, firmware, or software recorded on a non-transitory processor-readable recordable storage medium (i.e., a module itself is not software). In fact, a "module" should be construed as always including at least some physical, non-transitory hardware, such as a processor or a portion of a computer. Two different modules can share the same physical hardware (e.g., two different modules can use the same processor and network interface). The modules described herein can be combined, integrated, separated, and / or replicated to support various applications. In addition, instead of or in addition to the functions performed at a particular module, the functions described herein that are performed at a particular module can be performed at one or more other modules and / or by one or more other devices. In addition, these modules can be implemented across multiple devices and / or other components that are local or remote to each other. In addition, a module can be moved from one device and added to another device, and / or can be included in both devices.

[0235] The subject matter described herein can be implemented in a computing system that includes backend components (e.g., data servers), middleware components (e.g., application servers), or frontend components (e.g., client computers having a graphical user interface or a web browser through which a user can interact with an implementation of the subject matter described herein), or any combination of such backend, middleware, and frontend components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include local area networks ("LANs") and wide area networks ("WANs"), such as the Internet.

[0236] Approximating language, as used in the specification and claims, may be used to modify any quantitative representation that could permit variation without resulting in a change in the basic function associated therewith. "About," "substantially," or "approximately" may include values within 1% of a value, or in some embodiments, within 5% of a value, or in some embodiments, within 10% of a value in either direction (greater than or less than the value), unless otherwise stated or apparent from the context (unless the value does not permit more than 100% of a possible value). Accordingly, values modified by one or more terms such as "about," "approximately," or "substantially" are not limited to the precise values specified. In at least some instances, the approximating language may correspond to the precision of the instrument used to measure the value. Throughout this specification and the claims, range limitations may be combined and / or interchanged, such ranges are identified and include all the subranges subsumed therein, unless the context or language indicates otherwise.

[0237] Unless the contrary is expressly stated, the articles "a" and "an" as used in the specification and claims shall be understood to include plural referents. A claim or description that includes "or" between one or more members of a group is considered satisfied if one, more than one, or all of the group members are present in, employed in, or otherwise associated with a given product or process, unless there is a contrary indication or it is apparent from the context. The present disclosure includes such embodiments where exactly one member of the group is present in, employed in, or otherwise associated with a given product or process. The present disclosure also includes embodiments where more than one or all of the group members are present in, used in, or otherwise associated with a given product or process. Further, it is to be understood that the disclosed embodiments provide all variations, combinations, and permutations where one or more limitations, elements, clauses, descriptive terms, etc. from one or more of the listed claims are introduced into another claim (or any other relevant claim) that depends from the same base claim, unless otherwise stated or unless it would be apparent to one of ordinary skill in the art that there would be a contradiction or inconsistency. It is contemplated that all embodiments described herein are applicable, where appropriate, to all different aspects of the disclosed embodiments. It is also contemplated that any embodiment or aspect may be freely combined, where appropriate, with one or more other such embodiments or aspects. In cases where elements are presented in a list, such as in a Markush group or similar format, it is to be understood that each subgroup of the elements is also disclosed and any element may be removed from the group. It is to be understood that, generally speaking, where an embodiment or aspect of the disclosed embodiments is referred to as including a particular element, feature, etc., certain embodiments of the present disclosure or aspects of the present disclosure include or substantially include such element, feature, etc. For simplicity, these embodiments are not specifically set forth in so many words in every instance. It is also to be understood that any embodiment or aspect of the present disclosure may be explicitly excluded from the claims, regardless of whether the specific exclusion is stated in the specification. For example, any one or more of the active agents, additives, ingredients, optional reagents, organism types, disorders, subjects, or combinations thereof may be excluded.

[0238] In the case of the ranges given herein, embodiments of the present disclosure include embodiments that include endpoints, embodiments that exclude both endpoints, and embodiments that include one endpoint and exclude the other. Unless otherwise stated, it should be assumed that both endpoints are included. Further, it should be understood that, unless otherwise stated or apparent from the context and the understanding of one of ordinary skill in the art, in different embodiments of the present disclosure, a value indicated as a range may take on any specific value or sub-range within that range, down to one-tenth of the unit of the lower limit of the range, unless the context clearly dictates otherwise. It should also be understood that, in the case where a series of numerical values are stated herein, the present disclosure includes embodiments that similarly relate to any intermediate value or range defined by any two values in the series, and the lowest value may be regarded as the minimum value, and the highest value may be regarded as the maximum value. As used herein, numerical values include values expressed as percentages.

[0239] Although some variations have been described in detail above, other modifications or additions are possible.

[0240] In the above description and claims, phrases such as "at least one of" or "one or more of" may appear after a list of associated elements or features. The term "and / or" may also appear in a list of two or more elements or features. Unless the context in which it is used implicitly or explicitly contradicts, such phrases are intended to mean any element or feature listed separately, or any combination of any recited element or feature with any other recited element or feature. For example, the phrases "at least one of A and B"; "one or more of A and B"; and "A and / or B" each are intended to mean "A alone, B alone, or A and B together". Similar interpretations apply to lists including three or more 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" each are intended to mean "A alone, B alone, C alone, A and B together, A and C together, B and C together, or A and B and C together". Further, the term "based on" as used above and in the claims is intended to mean "at least partially based on", such that unrecited features or elements are also permitted.

[0241] In accordance with the desired configuration, the subject matter described herein can be implemented in a system, apparatus, method, and / or article. The embodiments set forth in the foregoing description do not represent all embodiments consistent with the subject matter described herein. Rather, they are only 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 can be provided in addition to those set forth herein. For example, the above embodiments can be directed to various combinations and sub-combinations of the disclosed features, and / or combinations and sub-combinations of several further features disclosed above. Additionally, the logical flows depicted in the figures and / or described herein need not be in the particular order shown or sequential order to achieve the desired result. Other embodiments are within the scope of the appended claims.

Claims

1. A system for electromagnetic radiation therapy, comprising: An electromagnetic radiation source configured to generate an EMR beam having a wavelength in the range of 1200 nm to 12000 nm; A beam shaper including a first axicon and a second axicon, configured to shape the EMR beam into a transverse annular energy distribution; An optical device configured to converge the EMR beam to a focal region located within the tissue; A beam scanning system configured to scan the focal region within the tissue; A window assembly located downstream of the optical device, configured to transmit the EMR beam and cool the tissue when placed in contact with the outer surface of the tissue, wherein 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, wherein the coolant chamber is configured to contain a coolant, the coolant including a fluorocarbon-based fluid that substantially does not absorb the EMR beam; and A controller configured to control the electromagnetic radiation source to generate the EMR beam having a plurality of pulses, wherein at least one of the plurality of pulses has a pulse duration of not less than 100 microseconds.

2. The system for electromagnetic radiation therapy according to claim 1, wherein at least one of the plurality of pulses has a pulse energy of not more than 100 mJ.

3. The system for electromagnetic radiation therapy according to claim 1, further comprising a cooler configured to cool the coolant to a temperature within the range of -20°C to 20°C.

4. The system for electromagnetic radiation therapy according to claim 1, wherein the optical device is further configured to converge the EMR beam with a numerical aperture of at least 0.

2.

5. The system for electromagnetic radiation therapy according to claim 1, further comprising an optically tissue-permissive medium located between the window assembly and the tissue, wherein the optically tissue-permissive medium includes at least one of glycerol, polyethylene glycol, and phosphate buffered saline.

6. The system according to claim 1 for electromagnetic radiation therapy, wherein at least one of the electromagnetic radiation source, the optical device, and the beam scanning system is configured to control one or more parameters of the EMR beam, and the one or more parameters include: The inner diameter of the transverse annular energy distribution, the outer diameter of the transverse annular energy distribution, the thickness of the transverse annular energy distribution, or the depth of the focal region within the tissue.

7. The system for electromagnetic radiation therapy according to claim 1, wherein the controller is configured to control the electromagnetic radiation source to ensure that the window assembly cools the tissue to a predetermined temperature before generating the EMR beam.

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

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