Patent Application
20080214988
1. Field of the Invention
The devices and methods disclosed herein relate to the ablation of soft and hard tissues with electromagnetic energy generally, including, without limitation, optical energy having wavelengths in the ultraviolet, visible and infrared ranges. Some embodiments relate to devices and methods that are used to ablate micro-holes in the treated tissue.
2. Description of the Related Art
Electromagnetic radiation, particularly in the form of laser light, has been used in a variety of cosmetic and medical applications, including uses in dermatology, dentistry, ophthalmology, gynecology, otorhinolaryngology and internal medicine. For most dermatological applications, the EMR treatment can be performed with a device that delivers the EMR to the surface of the targeted tissues. For applications in internal medicine, the EMR treatment is typically performed with a device that works in combination with an endoscope or catheter to deliver the EMR to internal surfaces and tissues.
As a general matter, existing EMR treatments are typically designed to (a) deliver one or more particular wavelengths (or a range (or ranges) of wavelengths) of EMR to a tissue to induce a particular chemical reaction, (b) deliver EMR energy to a tissue to cause an increase in temperature, or (c) deliver EMR energy to a tissue to damage or destroy cellular or extra cellular structures, such as for skin remodeling.
For skin remodeling, absorption of optical energy by water is widely used in two approaches: ablative skin resurfacing, typically performed with either CO2 (10.6 μm) or Er:YAG (2.94 μm) lasers, and non-ablative skin remodeling using a combination of deep skin heating with light from Nd:YAG (1.34 μm), Er:glass (1.56 μm) or diode laser (1.44 μm) and skin surface cooling for selective damage of sub-epidermal tissue. Non-ablative techniques offer considerably reduced risk of side effects and are much less demanding on post-operative care. However, clinical efficacy of the non-ablative procedure has not been satisfactory.
In the cosmetic field for the treatment of various skin conditions, alternative methods and devices have been developed that irradiate or cause damage in a portion of the tissue area and/or volume being treated. These methods and devices have become known as fractional technology. Fractional technology is thought to be a safer method of treatment of skin for cosmetic purposes, because tissue damage occurs within smaller sub-volumes or islets within the larger volume of tissue being treated. The tissue surrounding the islets is spared from the damage. Because the resulting islets are surrounded by neighboring healthy tissue the healing process is thorough and fast. Furthermore, it is believed that the surrounding healthy tissue aids in healing and the treatment effects of the damaged tissue.
Examples of devices that have been used to treat the skin using non-ablative procedures such as skin resurfacing include the Palomar® 1540 Fractional Handpiece, the Reliant Fraxel® SR Laser and similar devices by ActiveFX, Alma Lasers, Iridex, and Reliant Technologies.
The present invention uses ablative fractional methods and devices to perform cosmetic and other treatments and functions on hard and soft tissue, including skin tissue. In various embodiments, examples of which are described in greater detail below, improved devices and systems for ablating tissue by producing lattices of EMR-treated islets in tissues are provide as well as improved cosmetic and medical applications of such devices and systems. For example, in one embodiment, methods and devices are described for creating lattices of ablation islets. In some embodiments, methods and devices are described for selectively damaging a portion of a tissue volume being treated by applying EMR radiation to produce a lattice of EMR-treated islets, which absorb an amount of EMR sufficient to damage the tissue by killing cells at the surface of the tissue or otherwise causing ablation of the tissue in the EMR-treated islets, but not sufficient to cause bulk tissue damage.
Other embodiments include devices and methods that allow EMR to be precisely delivered such that uniform micro-holes and other types of EMR-treated islets having very small dimensions can be reliably formed. Methods and devices are described for ablating tissue to form micro-holes, micro-grooves, micro-voids and other micro-structures. For example, methods and devices are described for creating ablation islets that are small and precisely formed, for example, micro-holes in some embodiments having diameters of approximately 1-50 μm and micro-holes in other embodiments having diameters of a magnitude that is 10% or less of the wavelength used to create the micro-hole.
Other embodiments include various uses for ablated structures, including holes, grooves, voids, and various micro-structures. In some embodiments, ablative fractional treatments of tissue provide an alternative to non-ablative techniques that produces superior results. In other embodiments, ablative fractional methods and devices can be used to ablate holes, grooves, voids and other structures into tissue for various purposes, including, without limitation, skin tightening, wrinkle reduction, application of fillers, application of biologically inert materials, application of drugs, application of chromophores, application of optically transmissive substances, application of other substances to alter the optical characteristics of the tissue, application of drugs, and the application of other substances.
As examples, some of the embodiments described provide for one or more of the following:
One embodiment is a method for treating tissue comprising: ablating a portion of the tissue with electromagnetic radiation to form a plurality of channels extending a distance from a surface of the tissue; delivering a chromophore into and/or through the channel; and irradiating the chromophore with additional electromagnetic radiation to heat the chromophore.
Preferred variations of this embodiment can include one or more of the following. The chromophore can be heated, and the heat from the chromophore can be dissipated predominately through a thermal channel. The energy absorbed by the chromophore can initiate a photochemical reaction.
The chromophore can be many different elements, compounds, substances, mixtures or compositions, including, without limitation, carbon black, magnetic particles and electrically charged particles.
At least some of the chromophore can be delivered to a layer of fat tissue. The chromophore can be heated to a temperature sufficient to denature fat tissue in the layer. The chromophore can be delivered in a composition that allows the chromophore to accumulate in a structure in the tissue prior to irradiating the chromophore. The chromophore may be allowed to diffuse into the tissue prior to treatment.
Heat from the chromophore can damage many different parts of or structures in the tissue, including, without limitation, a hair follicles, sebaceous follicles, dermal tissue, and collagen. Heat from the chromophore can stimulate a healing response or other biological activity. Heat from the chromophore can ablate or coagulate surrounding tissue. Heat from the chromophore can be used in a photodynamic therapy.
The method can also include cooling a volume of the tissue, which can be cooled prior to irradiating the chromophore, while the chromophore is irradiated, and/or after the chromophore is irradiated. The tissue can be cooled to a temperature less than or equal to approximately 30 degrees Celsius, or more preferably to a temperature less than or equal to approximately 5 degrees Celsius.
The channels can extend to a depth in the range of approximately 5 micrometers to 5 millimeters. The channels can extend from the surface of the skin tissue to the epidermis, the dermis or below the dermis. The channels can have a width of approximately 1 micrometer to 1 millimeters, and more preferably between approximately 50 micrometers to 100 micrometers.
The fill-factor of the channels in a cross-sectional area can be between approximately 1 and 90 percent, or more preferably between approximately 25 and 40 percent. The center-to-center distance between adjacent channels can be between approximately 10 micrometers and 5 millimeters.
The tissue can be ablated with electromagnetic radiation having one or more wavelengths of between approximately 350 and 2000 nanometer, or more preferably between approximately 190 to 350 nanometers and/or 1.3 and 12 micrometers. The electromagnetic radiation applied to the chromophore can have one or more wavelengths in the visible spectrum and/or the infrared spectrum.
The method can further compris ablating a second portion of the tissue with electromagnetic radiation to form at least one additional channel extending a distance from a surface of the tissue. The additional channels can have dimensions different than those of the first channels. The additional channels can have different dimensions that the first channels, such as different width, shape or depth.
Another embodiment is a method for treating a volume of tissue comprising: forming a channel in the tissue by applying a first dose of electromagnetic radiation having at least one wavelength component suitable for ablating the tissue; delivering a chromophore into the channel; and heating the chromophore with a second dose of electromagnetic radiation.
Preferred variations of this embodiment can include one or more of the following. The method can further include applying a second dose of energy to the tissue. The second dose can be applied to the entire surface of the volume of tissue. The second dose can be applied to portions of the volume of tissue to produce an array of treatment islets. The chromophore can be delivered into the channel or can be delivered into an through the channel. Some or all of the chromophore can remain in the channel prior to irradiation of the chromophore, depending on the application. Similarly, some or all of the chromophore can be forced into or diffuse into the tissue prior to irradiation of the chromophore, depending on the application.
Another embodiment is a method for performing a cosmetic procedure comprising: creating a set of voids in skin tissue by applying electromagnetic radiation; introducing a substance into the voids; and applying energy to the substance to increase the temperature of the substance.
Preferred variations of this embodiment can include one or more of the following.
The substance can be introduced into the voids by many different mechanisms, including, without limitation, by forcing at least a portion of the substance through the voids and into the skin tissue, vibrating the tissue, applying positive pressure to the tissue, alternately applying positive and negative pressure to the tissue, applying an electrical field to the tissue, applying a magnetic field to the tissue, manually manipulating the tissue, massaging the tissue, stretching the tissue, compressing the tissue, alternately stretching and compressing the tissue, applying a pressure wave to the surface of the tissue, applying a jet containing the substance to the surface of the tissue, applying energy to the substance to cause cavitation within the tissue and applying ultrasound to the surface of the tissue.
The substance can be many different forms, including, without limitation, one or more of the following: elements, compounds, compositions, mixtures, suspensions, particulates, crystals, liquids, solids, and gasses.
Another embodiment is a device for treating soft tissue. The device includes a source of optical radiation configured to generate sufficient optical radiation to ablate tissue; an output aperture configured to emit the optical radiation onto the soft tissue in a pattern of treatment areas separated by untreated areas such that the optical radiation forms voids in the tissue at the treatment areas; an optical path extending from the source of the optical radiation to the output aperture, and configured to deliver the optical radiation to the soft tissue; a chromophore applicator configured to inject a chromophore into the voids formed by the optical radiation generated by the source during operation.
Preferred variations of this embodiment can include a jet configured to spray the chromophore into the voids.
Another embodiment is a method for treating soft tissue with electromagnetic radiation comprising: forming a plurality of channels in the skin tissue by applying electromagnetic radiation; introducing a substance into the voids to alter an optical property of the skin; and irradiating a chromophore in the tissue with additional electromagnetic radiation; wherein the optically transmissive substance facilitates the transmission of electromagnetic radiation through the tissue and to the chromophore.
The following drawings are illustrative and are not meant to limit the scope of the invention as encompassed by the claims.
When using electromagnetic radiation (EMR) and other forms of energy to treat tissues, there are substantial advantages to producing lattices of treated islets in the tissue rather than large, continuous regions of treated tissue. The lattices are periodic patterns of islets in one, two or three dimensions in which the islets correspond to local maxima of treated tissue. The islets are separated from each other by non-treated tissue (or differently-or less-treated tissue).
The EMR-treatment results in a lattice of EMR-treated islets which have been exposed to a particular wavelength or spectrum of EMR, and which is referred to herein as a lattice of “islets.” When the absorption of EMR energy results in significant temperature elevation in the EMR-treated islets, the lattice is referred to herein as a lattice of “thermal islets.” When an amount of energy is absorbed that is sufficient to significantly disrupt cellular or intercellular structures, the lattice is referred to herein as a lattice of “damage islets.” When an amount or energy is absorbed that is sufficient to ablate the tissue being treated, the lattice is referred to herein as a lattice of “ablated islets” or “ablation islets.” An extensive discussion of the various types of EMR-treated islets (such as damage, thermal and photochemical islets) as well as the parameters and specification of devices used for form such types of islets can be found in the applications incorporated by reference above, and the bulk of that disclosure is not repeated herein
The inventors have further discovered that when ablation islets are created on a small scale, the islets have many advantages, which are described below in conjunction with various embodiments. The inventors have also discovered devices and methods for creating such islets on a small scale, referred to herein as micro-islets. Although various forms of energy can be used, including ultrasound energy, the exemplary embodiments below are chiefly described with reference to using EMR to create EMR-treated islets.
A. Ablation Islets
One specific type of EMR-treated islet that is particularly useful is the ablation islet. An ablation islet in its simplest form is a void in tissue formed by ablation processes that remove a portion of the tissue for form the void. However, due to the complexity of EMR-tissue interactions and the dynamic nature of living tissue, the islet may be more complex. The damage to the tissue in the islet is to the degree that the tissue is vacated to form empty space or is altered in composition, such as, for example, in the case of a channel of tissue that is damaged such that the channel is vacated or primarily filled with water, other fluid and/or remnants or vestiges of the damaged tissue (e.g., tissue fibers or other substances). For example, during ablation, some or all of the tissue may not be removed from the “void” and may remain in the void as desiccated tissue and/or debris from ablation processes. Furthermore, the “void” may be filled with water or other substances as the tissue reacts to the ablative injury to the tissue. Similarly, the shape of the “void” may change. For example, the walls of the “void” may partially or completely collapse as a result of tissue that is removed or as a result of the healing process. Other processes may also be involved, such as cavitation within the tissue, that will result in an alteration in the size and shape of the void. Thus, a “void” resulting from an ablative process may not necessarily result in empty space or a particular shape being formed within the tissue.
B. Micro-Islets
When the ablated islets are sufficiently small, for example, on the order of approximately 2 mm or less, the islets are also referred to herein as a lattice of “micro-islets.” In some embodiments, an ablation islet is a small volume in the tissue in which the tissue has been damaged, ablated or otherwise treated to form small holes, channels, grooves, openings, chambers and/or similar structures in the tissue. (For convenience, such structures are referred to collectively as micro-islets, micro-voids and/or micro-structures. The term micro-hole is used extensively throughout the specification as an exemplary embodiment of a micro-islet, but many other embodiments are possible. For example, the shape of the micro-islets may have many forms, including, without limitation, micro-holes, micro-grooves, micro-voids and other micro-structures. While the term “micro” connotes that the resulting structure is significantly smaller in volume than the overall volume of the tissue being treated (or, similarly, that the area of tissue to which the energy is applied to form a micro-islet is significantly smaller than the total area of tissue being treated), it does not require that the resulting micro-islet be microscopic in size. Micro-holes can be various sizes, including, without limitation, micro-holes that are macroscopic or microscopic in size. For example, a lattice of micro-holes on nail tissue can have a diameter of 50 micrometers, but much smaller micro-holes are possible, and larger micro-holes are also possible. Additionally, the orientation of the islets can be varied from normal to a tissue surface to parallel with the surface or other angles or orientations, including islets that are curved or otherwise are not formed along a straight path.
Micro-islets can be used for a variety of purposes such as, for example, the application of drugs and medicines, the injection of fillers and other inert substances, and the removal of fat tissue or other substances, skin resurfacing, skin rejuvenation, skin tightening and wrinkle removal. Micro-holes can be used as channels for the local delivery of the desirable therapeutic compound(s) to the target (treated) anatomical areas by diffusion or by employing but not limited to the other approaches, such as vesicle/particle transporters, by physical, chemical or electrical manipulations (for instance electroporation, iontoporation, sonophoresis, magnetophoresis, photomechanical waves, niosomes, transfersomes etc.). Micro-holes can be created in any tissue, such as skin, nail, bone, muscle, etc., and at any anatomical location.
Referring to
In an ablative process in which micro-holes or other micro-structures are formed, treatment parameters can be chosen such that a relatively small volume or zone of coagulated tissue surrounds the volume of ablated tissue that results in a void that forms a micro-hole or other micro-structure. In other words, the ratio of the coagulated tissue volume to the ablated tissue volume can be controlled. The ratio can be very small (such as from about 10% to essentially zero), e.g., by choosing wavelengths that are highly absorbed, using short pulses of EMR, and/or quickly evacuating any ablated tissue such that heat from the tissue is not allowed to disperse to surrounding tissues. Conversely, the ratio can be made to be much larger, i.e., a relatively large volume of coagulated tissue surrounding the ablated tissue volume (such as 50% or greater), by choosing treatment parameters that allow heat to disperse into the surrounding tissue during ablation. For example, ablating tissue using wavelengths that are typically used in non-ablative processes, such as approximately 1320 nm, 1450 nm and 1540 nm, at intensities that will ablate tissue, typically would result in larger coagulation zones surrounding the volume of ablated tissue.
A typical zone of coagulation surrounding and/or adjacent to an ablation zone will have a thickness of approximately 5 μm to 100 μm, but other dimensions are possible. Referring to
Referring to
The spot size that can be created (and, thus, the resulting micro-hole) is proportional to the wavelength: the smaller the wavelength, the smaller the micro-hole that can be created.
If non-coherent light is applied, the smallest spot size that is theoretically possible is the largest wavelength among the wavelengths that are applied to achieve a treatment effect on the tissue, such as an ablated micro-hole. This would not include longer wavelengths that do not ablate the tissue or otherwise have an effect that forms an EMR-treatment islet. For example, if one or more spectral bands of EMR are applied to the tissue, but only a subset, subsets, or sub-band(s) of the EMR are actually used to ablate or otherwise treat and form the islet, the smallest possible diameter of the resulting micro-hole will be the size of the largest wavelength in the sub-band(s) or subset(s) of EMR.
Because smaller focal areas are possible using shorter wavelengths, one effective means for creating very small micro-holes or other micro-islets is the use of an Eximer laser or another laser to produce EMR in the ultraviolet range.
The focal depth (Z0) of the spot size is a function of the diameter of the focal point, which is determined by the following equation:
Thus, in an example where the focal point has a diameter of 30 μm and the wavelength is 3 μm, the focal depth is approximately 943 μm.
As seen in
In other embodiments, the power density may be modulated during the formation of a single micro-hole. For example, a first pulse of EMR can be applied at a first power density and a second pulse can be applied at a different power density. If the power densities of multiple pulses are alternated in this fashion, micro-holes having varying diameters can be formed. Such micro-holes may have various benefits, for example, an increase in surface area that can be used to deliver substances such as drugs or clearing substances more effectively or at a faster rate. Similarly, the power density can be modulated, for example, between pulses, during pulses or during the application of EMR in a continuous or quasi-continuous wave, to form micro-holes of varying shapes, such as, for example a conical-like shape. A conical shape in which the narrow portion of the cone is at the surface of the tissue and in which the wider base of the cone lies within the tissue could be used to create a micro-hole having a relatively larger volume, which can be used, for example, to hold a substance, and also having a relatively small opening, which will close more quickly than a larger hole. (The closure rates of micro-holes are discussed in greater detail in conjunction with
When using ablation to form a micro-hole, the ablation is preferably performed in conjunction with a device to remove the ablated material, although this is not required. When tissue is ablated, remnants of the tissue generally remain in the micro-holes. This can increase the amount of refraction and otherwise decrease optimum performance of the device forming the micro-holes. The micro-holes are formed more precisely when the ablated material is removed. There are many embodiments possible of a system, device or method to remove tissue, such as, for example, a device that is synchronized to produce a short pulse of air at high pressure, which expels the ablated material immediately after a pulse of EMR is applied before the material has a chance to settle in the micro-hole that is being formed.
Many different embodiments are possible for removing tissue. For example, devices in which the EMR is delivered through an optical element such as a lens that is not in contact with the tissue can include a device that directs air or other gas into the space between the tissue and the optical element to remove the remnants of the ablated tissue. In embodiments where an optical element from which EMR is delivered is in contact with the tissue, other structures can be used. For example, the optical element may contain ribs, ridges, channels or other structures through which a high-pressure gas may be pulsed such that the remnants of ablated tissue are removed through those structures as the device is moved relative to the tissue during operation. Similarly, in still other embodiments, some or all of the remnants of the ablated tissue can be left within the micro-holes. However, if tissue is ablated and not subsequently vacated from the EMR-islet, additional factors will affect the characteristics of the resulting micro-hole. For example, scattering within the tissue, including the remnants of the ablated tissue, may increase and impact the size, shape and other characteristics of the micro-hole.
While the above has been discussed in terms of the threshold of ablation, the concept can be applied similarly to other types of EMR-Islets, for example, by using thresholds of damage instead of thresholds of ablation. Non-ablative techniques may be used to form similar micro-structures, such as zones of thermally damaged tissue or small zones of healthy tissue surrounded by zones of EMR-treated tissue, such as, for example, thermally treated tissue and/or ablated tissue.
C. The Shape of Ablated EMR-Islets
The optical islets can be formed essentially in any shape, limited only by the ability to control EMR beams within the tissue. Thus, depending upon the wavelength(s), temporal characteristics (e.g., continuous versus pulsed delivery), and fluence of the EMR; the geometry, incidence and focusing of the EMR beam; and the index of refraction, absorption coefficient, scattering coefficient, anisotropy factor (the mean cosine of the scattering angle), and the configuration of the tissue layers; and the presence or absence of exogenous chromophores and other substances, the islets can be variously-shaped volumes extending from the surface of the skin through one or more layers, or extending from beneath the surface of the skin through one or more layers, or within a single layer.
Micro-islets may extend relatively deeply into the tissue, for example, from the surface of the skin into the subcutaneous fat layer. There are several mechanisms available to create relatively deep micro-structures. For example, a device may have one or more of the following features: an optical system designed for irradiating tissue below the surface; a mechanism to adjust the focus deeper into the tissue as the micro-structure is formed; a high-aspect ratio; and a relatively longer focal length. Other mechanisms that may be employed include, without limitation, delivery of EMR via a micro-fiber that is inserted into the microstructure as it is sized to essentially form a channel or tunnel in the tissue during the ablation process; local freezing of tissue that is to be ablated; and mechanical stretching of the skin to decrease density and increase EMR penetration.
In other embodiments, repeated pulsing that ablates a sub-volume of tissue from the micro-structure during the ablation process. However, when a single pulse of EMR is applied in a system, for example, aligned such that a focal area of the EMR is at or just below a tissue surface, multiple pulses of energy will gradually have less intensity deeper in the tissue as the beam diverges (as shown in
If multiple pulses are used to create a micro-structure, the pulses can be timed to allow the following pulse to be most effective. For example, the parameters may be selected to create a shock wave that temporarily expands a micro-hole during ablation, and, in some embodiments, the second pulse may be ideally timed to occur when the micro-hole is expanded, especially in embodiments where the scattering effects of ablated material within the micro-holes can be used advantageously to create particular shapes or dimensions within the micro-holes.
Furthermore, negative pressure may be applied to the tissue during the formation of a micro-islet, which will decrease the temperature of vaporization of the tissue. Negative pressure can also be used to modulate or control the process of formation of all micro-structures, both shallow and deep, including the width, depth, and shape of the micro-structure. For example, decreasing the pressure will decrease the temperature at which tissue is ablated, while increasing the temperature will increase the temperature at which tissue is ablated. Thus, for example, by modulating the pressure during the formation of the microstructure, the amount of tissue that is ablated per pulse can be changed.
Referring to
The parameters for obtaining a particular islet shape can be determined empirically with only routine experimentation. For example, a 2790 nm laser operating with a low conversion beam at approximately 0.005-2 J and a pulse width of 0.5-2 millisecond, can produce a generally cylindrically shaped islet. Alternatively, a 2940 nm laser operating with a highly converting beam at approximately 0.5-10 J and a pulse width of 0.5-2 millisecond, can produce a generally ellipsoid-shaped islet.
D. Grooves and Micro-Grooves
One form of an ablation islet that is particularly useful in certain applications is an ablated groove extending in a row some distance along the surface of the skin tissue. In particular, the ablated groove may be a micro-groove. For example, referring to
Grooves may also have a range of depths. For example, referring to
The fill factor (discussed in more detail below) can be from about 1% to about 90% and more preferably from about 1% to about 50%.
Groove structures may also take on many shapes and patterns. For example, referring to
Furthermore, grooves can be formed by a number of different mechanisms. For example, a micro-groove can be formed by a single beam continuously scanned along a path to ablate tissue to form a groove along that path. Micro-grooves can be formed using a phase array. A cylindrical lens or similar lens may be used to focus EMR along a path on the tissue where the groove will be formed. Additionally, as shown in
E. Fill Factor
In a given lattice of EMR-treated islets, the percentage of tissue volume which is EMR-treated is referred to as the “fill factor” or f, and can affect whether optical islets become thermal islets, damage islets or photochemical islets. The fill factor is defined by the volume of the islets with respect to a reference volume that contains all of the islets. The fill factor may be uniform for a periodic lattice of uniformly sized EMR-treated islets, or it may vary over the treatment area. Non-uniform fill factors can be created in situations including, but not limited to, the creation of thermal islets using topical application of EMR-absorbing particles in a lotion or suspension (see below). For such situations, an average fill factor (favg) can be calculated by dividing the volume of all EMR-treated islets Viislet by the volume of all tissue Vitissue in the treatment area,
Generally, the fill factor can be decreased by increasing the center-to-center distance(s) of islets of fixed volume(s), and/or decreasing the volume(s) of islets of fixed center-to-center distance(s). Thus, the calculation of the fill factor will depend on volume of an EMR-treated islet as well as on the spacing between the islets. In a periodic lattice, where the centers of the nearest islets are separated by a distance d, the fill factor will depend on the ratio of the size of the islet to the spacing between the nearest islets d. For example, in a lattice of parallel cylindrical islets, the fill factor will be:
where d is the shortest distance between the centers of the nearest islets and r is the radius of a cylindrical EMR-treated islet. In a lattice of spherical islets, the fill factor will be the ratio of the volume of the spherical islet to the volume of the cube defined by the neighboring centers of the islets:
where d is the shortest distance between the centers of the nearest islets and r is the radius of a spherical EMR-treated islet. Similar formulas can be obtained to calculate fill factors of lattices of islets of different shapes, such as lines, disks, ellipsoids, rectanguloids, or other shapes.
Because untreated tissue volumes act as a thermal sink, these volumes can absorb energy from treated volumes without themselves becoming thermal or damage islets. Thus, a relatively low fill factor can allow for the delivery of high fluence energy to some volumes while preventing the development of bulk tissue damage. The lattice thermal relaxation time (LTRT) may be defined as the characteristic cooling time when the maximum temperature within the islet reaches the intermediate value between the initial and stationary temperatures. Using this definition the LTRT of a very sparse lattice equals the thermal relaxation time (TRT) of an individual islet. Actually, for such a lattice each islet cools independently on the others. For denser lattices the temperature profiles from different islets overlap causing the LTRT to decrease. To estimate such cooperative effect, the ratio of LTRT to TRT as a function of the fill factor (f) for the particular case of the 2D lattice was calculated (
Finally, because the untreated tissue volumes act as a thermal sink, as the fill factor decreases, the likelihood of optical islets reaching threshold temperatures to produce thermal islets or damage islets also decreases (even if the EMR power density and total exposure remain constant for the islet areas).
The center-to-center spacing (i.e., pitch) of islets is determined by a number of factors, including the size of the islets and the treatment being performed. Generally, it is desired that the spacing between adjacent islets be sufficient to protect the tissues and facilitate the healing of any damage thereto, while still permitting the desired therapeutic effect to be achieved. In general, the fill factor can vary in the range of 0.1-90%, with ranges of 0.1-1%, 1-10%, 10-30% and 30-50% for different applications. The interaction between the fill factor and the thermal relaxation time of a lattice of EMR-treated islets is discussed in detail below. In some embodiments producing thermal islets, the fill factor may be sufficiently low to prevent excessive heating and damage to islets. In some embodiments producing damage islets, the fill factor may be sufficiently low to ensure that there is undamaged tissue around each of the damage islets sufficient to prevent bulk tissue damage and to permit the damaged volumes to heal. The specific parameters, such as the degree of separation and the ratio of the volume of islets to the volume of tissue that is treated but in which islets are not formed, will vary depending on the application. In some embodiments, for example, the entire treated tissue could be irradiated to some degree, such as to cause a thermal reaction in the tissue or a degree of damage in the tissue while the EMR-treated islets would be formed within that tissue and would have a greater degree of damage. For example, a lattice of damage islets could be formed within a volume of tissue that has been treated to provide an underlying bias of heat throughout the volume of tissue. As another example, a lattice of islets of ablative damage could be provided in a tissue volume that has been damaged to a lesser degree. Such an embodiment may be useful, for example, to create holes or channels in damaged fat tissue to insert or extract substances or for other purposes.
A. Products and Methods for Ablating Tissue
In one embodiment, referring to
Electromagnetic radiation 502 can be any radiation useful for ablating tissue, and, in this embodiment, is electromagnetic radiation having a wavelength of approximately 2940 nm (nanometers). Other wavelengths that are particularly useful in other embodiments similar to that shown in
In device 500, electromagnetic radiation (“EMR”) 502 is produced by radiation source 504, which in the present embodiment is a Q-switched YGG:YAG laser. However, any mechanism for producing EMR at the desired wavelength, power and duration may be used, including other lasers, flashlamps, other lamps, and other sources of EMR. Electromagnetic radiation 502 is emitted from an end 508 of radiation source 504.
Electromagnetic radiation 502 travels through optical assembly 506. Optical assembly 506 includes first, second, and third lenses 510, 512, and 514, prism 517, and transmission tube 522. Transmission tube 522 has a lens array 524 and an aperture 526 that serves as an opening through which the beams of EMR are transmitted. In operation, device 500 functions as a laser handpiece that is made relatively more compact by folding the path that electromagnetic radiation 502 back on itself via a 180 degree turn. Electromagnetic radiation 502 is emitted from radiation source 504 and passes through first lens 510. First lens 510 is a convergent imaging lens that focuses EMR 502 into prism 517. EMR 502 strikes a first reflective end 518 of prism 517. End 518 is oriented at an angle of 45 degrees relative to the line of travel of electromagnetic radiation 502, and causes electromagnetic radiation 502 to be reflected (via total internal reflection within prism 517) at a 90 degree angle toward a second reflective end 520 of prism 517. Second end 520 similarly is oriented at an angle of 45 degrees relative to the line of travel of electromagnetic radiation 502, and causes electromagnetic radiation 502 to be reflected again at a 90 degree angle toward and through transmission tube 522.
Many alternate embodiments are possible to achieve the result, including, for example, the use of reflective materials, coatings, and/or mirrors. Similarly, depending on the design considerations, other embodiment may have other configurations for the path that EMR travels, such as, for example, a straight path with no turn, an “L”-shaped path or other configurations. Similarly, the EMR could travel along an optical fiber from a source, which could be located in a handpiece, in a base unit, or other configuration.
After EMR 502 exits prism 517, EMR 502 is focused through focal spot 530 and begins to diverge. EMR 502 then travels through second lens 512, which is a convergent lens that makes the beam of EMR 502 less divergent after is exits prism 517. EMR 502 diverges until it reaches lens array 524. At that point, EMR 502 has a perpendicular cross-section that is circular in shape and that is smaller than the area of lens array 524, which is approximately square in shape. Lens array 524 is an array of micro-lenses that focus EMR beam 502 into an array of beams 528. One suitable lens array is manufactured by SUSS MicroOptics SA, #112-0571. Lens array 524 produces 770 beams each having a pitch of 360 microns and a beam diameter of 110 micrometers per beam. Lens array 524 produces a pattern of EMR-treated islets as shown in
The array of beams 528 then travels through third lens 514. Lens 514 is a convergent imaging lens that re-images the array of beams along an imaging plane that corresponds to the location of an aperture 526. The imaging plane (and aperture 526) are located approximately 27 mm from lens 514.
Aperture 526 is a grating or mesh consisting of a metal surface having holes aligned with the position of the beams in the array 528. The holes of aperture 526 are configured as shown in
The use of the aperture and/or other mechanisms such as stretching the skin or conforming the skin surface to another surface allows the device to uniformly irradiate an area of tissue with an array of beams. Thus, the use of such a device improves the precision of the device and allows it to create even smaller holes on a consistent basis. For example, referring to
By using a mesh grating with an even surface (which can be flat or contoured), the surface tissue can be precisely aligned with the focal plane of the beams to allow uniform micro-holes to be created. For example, referring to
In an alternative embodiment, the surface of an aperture is curved to conform to optical characteristics of an optical system. For example, if an array of beams is imaged with an imaging lens, the focal plane of the imaging lens will have a contour that is not flat. In that case, the alignment device can be contoured to match the focal plane produced by the optical system to allow the tissue to be aligned precisely with the focal plane of the device. Referring to
In some embodiments, the beam can have an intensity such that the ability to ablate, damage or otherwise treat the tissue extends to a portion that is less than or greater than the length of the focal depth. Furthermore, it should be noted that, regardless of the intensity of the beam, a micro-hole can be increased in size, including depth, by firing multiple pulses of EMR. Additionally, if required, the focal point can be adjusted, e.g., by repositioning the focal plane deeper into the tissue between pulses or in a continuous fashion during the pulse, or during the application of EMR, for example, if quasi-continuous wave or continuous wave modes of operation are used.
While such an aperture or similar structure is expected to produce superior results when forming small micro-holes, such a device or structure is not required. For example, a higher intensity pulse can be used to create micro-holes in embodiments where the variations in the tissue surface terrain exceed the focal depth of the device. Thus, in other embodiments, no such aperture, window or similar mechanism to ensure the uniformity of the distance of the optical elements to the tissue to be treated is included. However, when attempting to precisely create uniform holes on the order of approximately 50 μm or less, the better practice is thought to be to align the surface of the tissue to a uniform distance using a device or structure such as aperture 526 (or another device or structure that aligns the surface to the desired distance).
In operation, the surface of the tissue to be ablated will be pressed against aperture 526, and the array of beams will ablate the surface of the tissue. In the present embodiment, a safety mechanism such as a contact sensor preferably is included to prevent the laser from firing when the tissue is not in contact with the aperture 526. That will prevent, among other things, the condition where the laser is accidentally fired while the aperture 526 is off the surface of the tissue. (Many other configurations are possible. For example, an alternative optical assembly could result in the beams exiting the device in a parallel or a slightly divergent orientation, to prevent the array of beams from being applied to the surface at a greater intensity, thereby potentially damaging the tissue to an excessive degree) due to the convergence of the beams at the exit the device.)
During operation, referring again to
Many other patterns, such as, for example, hexagonal, rectangular, circular, triangular, etc., could also be used. The various patters have different advantages. For example, a hexagonal pattern would be preferable for providing greater beam densities, while an orthogonal pattern allows comparatively greater regions of untreated tissue between the volumes of treated tissue and/or allows relatively larger beam diameters. Additionally, the pattern need not be uniform and patterns created by beams having varying relative cross-sectional areas and shapes can be used alone or in combination.
Many other embodiments are possible. For example, the specifications for devices similar to device 500 can include those listed in Table A below (although the specifications are exemplary only of such embodiments, and do not encompass all possible embodiments or all possible operating parameters for devices similar in structure to device 500).
Furthermore, in still other embodiments, the EMR from the energy source can be focused by an optical device and/or shaped by masks, filters, optics, or other elements in order to create islets of treatment on the subject's skin. In some embodiments, components found in device 500 may not be present, such as, for example, prism 517 or lens array 524. Other embodiments could include different combinations, types and number of optical components. Other embodiments could be configured to irradiate the tissue without the device being in contact with the tissue or by having an offset or spacer that spaces a transmission opening or other source of radiation some distance from the surface of the tissue during operation. In yet another embodiment, there is no cooling mechanism such that there is only passive cooling between the contact plate and the skin.
Additionally, other embodiments could include mechanisms other than lens arrays, such as scanning devices, partially reflective mirrors, etc. For example, one alternate embodiment could include a scanner that uses a single beam or several beams repeatedly to create the columns of damage in the tissue. Similarly, referring to
Furthermore, the characteristics of the resulting columns can be controlled by modulating the pulses of the beams that are applied to the tissue. This can be done, for example, spatially or temporally. In some embodiments, the spatial geometry of the beams can be designed to create resulting columns having specific characteristics. In other words, by varying the geometry of the beams, including the overall pattern, the shape of the individual beams and/or the combination of differently shaped beams, the dimensions and other characteristics of the resulting columns of damage in the treated tissue can be controlled. For example, by increasing the relative cross-sectional area of the individual beams, the depth of the columns into the tissue can be increased.
As another example, the shape of the footprint that the EMR islets form on the tissue can be varied to suit a particular application. For example, the footprint of the array of beams 528 in device 500 is circular. There are various methods to control the shape of the footprint. In a scanning system, the system can be programmed to direct the beam in a pre-designated pattern. Similarly, in embodiments using an optical imaging system similar to that of device 500, the beam of EMR can be conditioned prior to passing through the lens array to have the desired cross-sectional shape.
One potential design consideration is the amount of blurring that occurs in the periphery of the array of beams 528. For example, in tests using device 500, some degree of blurring of individual beams occurs in the periphery of the array of beams 528. The blurring, which is illustrated in
Referring to
Referring to
In still other embodiments, additional sensing devices can be employed to control the treatment parameters. For example, referring again to
Still other embodiments can have a hyperbaric chamber in communication with the tissue to apply substances, for example, oxygen to help the wound healing process. In still other embodiments, a vacuum chamber can be provided that is used to clean the micro-hole of debris. In still other embodiments, combinations of capabilities are combined to, for example, clean the micro-holes and administer a substance to promote healing before, during or after treatment.
B. Use of Various Wavelengths and Modulation of Wavelengths
In various embodiments, additional or other lasers or other EMR sources can be used to produce EMR of other wavelengths. In the case of non-coherent sources, various mechanisms can be used including the use of one or more filters, including adjustable or replaceable filters that allow the wavelength to be changed. In the case of coherent EMR sources, a tunable source can be used. When lasers specifically are used, the lasing medium may be altered, e.g., by employing different mediums and/or adjusting the doping of the lasing medium. For example, the following wavelengths could be used in other embodiments:
The above table is exemplary only, and the various types and concentrations of dopants for the laser crystals that will produce various wavelengths are understood by those skilled in the art. Many other laser types and configurations are possible, including potentially other solid-state lasers as well as gas, eximer, dye, tunable, semiconductor and other types of lasers. Furthermore, other wavelengths could be generated using an optical parametrical oscillator to generate EMR having a wavelength in the range of approximately 2500-3100 nm as well as to generate even longer wavelengths, for example, by manipulating EMR at a particular wavelength, e.g., 690 nm, to generate EMR having a wavelength that is twice as long, e.g., 1380 nm. (This is similar to the concept of frequency doubling or tripling in which EMR of a particular wavelength, e.g., 1040 nm, is manipulated to generate EMR having a shorter wavelength, e.g., 520 nm.) Although certain wavelengths and combinations of wavelengths will be advantageous in particular applications, essentially any wavelength of EMR can be used. However, wavelengths above 0.29 μm are preferred due to the potentially hazardous impact smaller wavelengths may have on human tissue in vivo.
In still others embodiments, various sources or a tunable source can be used to modulate the parameters of the EMR that is applied, and, thus, control the resulting dimensions of the micro-holes that are created. In one such embodiment, wavelength can be modulated to control the dimensions of the micro-hole. Referring to
This phenomenon can be used to control the shape of the resulting micro-holes. For example, referring to
C. Alternate Embodiments For Creating Ablation Islets
In still other embodiments, the energy source may be any suitable optical energy source, including coherent and non-coherent sources, able to produce optical energy at a desired wavelength or a desired wavelength band or of multiple wavelengths or in multiple wavelength bands. For example, wavelengths that have complimentary physical characteristics can be used, such as one wavelength that is highly absorbed by a particular type of tissue in combination with or followed by a wavelength having a lower absorption, for example, to serve a hemostatic function and seal any bleeding blood vessels.
In another embodiment,
A suitable optical impedance matching lotion or other suitable substance would typically be applied between plate 244 and tissue 246 to provide enhanced optical and thermal coupling. Tissue 246, as shown in
The system 208 of
Additionally or alternatively, the image can employ “cross-hairs” or other mechanisms to more precisely focus the beams of EMR. For example, in one embodiment, the device is properly focused when the “cross-hairs” or other image is sharp, and can be fired-either manually or automatically. If all or a portion of the “cross-hairs” or other image are blurred and appear out of focus, the operator has a visual indication that the device is not properly focused or is at an improper distance or alignment relative to the tissue being treated. The operator would then know not to fire the device and/or the device could be designed to automatically prevent firing while providing the visual indication to the operator to aide in properly positioning the device.
Throughout this specification, the terms “head”, “hand piece” and “hand held device” may be used interchangeably.
D. Electromagnetic Radiation Sources
The energy source 210 may be any suitable optical energy source, including coherent and non-coherent sources, able to produce optical energy at a desired wavelength or a desired wavelength band or of multiple wavelengths or in multiple wavelength bands. The exact energy source 210, and the exact energy chosen, may be a function of the type of treatment to be performed, the tissue to be heated, the depth within the tissue at which treatment is desired, and of the absorption of that energy in the desired area to be treated. For example, energy source 210 may be a radiant lamp, a halogen lamp, an incandescent lamp, an arc lamp, a fluorescent lamp, a light emitting diode, a laser (including diode and fiber lasers), the sun, or other suitable optical energy source. In addition, multiple energy sources may be used which are identical or different. For example, multiple laser sources may be used and they may generate optical energy having the same wavelength or different wavelengths. As another example, multiple lamp sources may be used and they may be filtered to provide the same or different wavelength band or bands. In addition, different types of sources may be included in the same device, for example, mixing both lasers and lamps.
Energy source 210 may produce electromagnetic radiation, such as near infrared or visible light radiation over a broad spectrum, over a limited spectrum, or at a single wavelength, such as would be produced by a light emitting diode or a laser. In certain cases, a narrow spectral source may be preferable, as the wavelength(s) produced by the energy source may be targeted towards a specific tissue type or may be adapted for reaching a selected depth. In other embodiments, a wide spectral source may be preferable, for example, in systems where the wavelength(s) to be applied to the tissue may change, for example, by applying different filters, depending on the application. Acoustic, RF or other EMF sources may also be employed in suitable applications.
For example, UV, violet, blue, green, yellow light or infrared radiation (e.g., about 290-600 nm, 1400-3000 nm) can be used for treatment of superficial targets, such as vascular and pigment lesions, fine wrinkles, skin texture and pores. Blue, green, yellow, red and near IR light in a range of about 450 to about 1300 nm can be used for treatment of a target at depths up to about 1 millimeter below the skin. Near infrared light in a range of about 800 to about 1400 nm, about 1500 to about 1800 nm or in a range of about 2050 nm to about 2350 nm can be used for treatment of deeper targets (e.g., up to about 3 millimeters beneath the skin surface).
1. Coherent Optical Sources
Two particularly effective sources for the fractional ablation of tissue include an Er:YAG Laser operating at 2940 nm and an Er:YSGG Laser operating at 2780 nm.
Exemplary treatment parameters for Er:YAG and Er:YSGG laser sources are shown in Table B below.
Lasers and other coherent light sources can be used to cover wavelengths within the 100 to 100,000 nm range. This includes wavelengths that are in wavelength ranges typically used for non-ablative procedures such as 1320 nm, 1450 nm and 1540 nm. Examples of coherent energy sources are solid state, dye, fiber, and other types of lasers. For example, a solid state laser with lamp or diode pumping can be used. The wavelength generated by such a laser can be in the range of 400-3,500 nm. This range can be extended to 100-20,000 nm by using non-linear frequency converting. One such laser is a 3 μm Erbium laser. Solid state lasers can provide maximum flexibility with pulse width range from femtoseconds to a continuous wave, preferably in a range of approximately 1 femtosecond to 100 milliseconds. When very short pulses of EMR are used to create micro-islets, the wavelength has a smaller effect. For example, when a pulse on the order of several femtoseconds is applied, the relationship between the wavelength and the focal area is less pronounced such that longer wavelengths may be used to create small structures.
Another example of a coherent source is a tunable laser. For example, a dye laser with non-coherent or coherent pumping, which provide wavelength-tunable light emission. Dye lasers can utilize a dye dissolved either in liquid or solid matrices. Typical tunable wavelength bands cover 400-1,200 nm and a laser bandwidth of about 0.1-10 nm. Mixtures of different dyes can provide multi wavelength emission. Dye laser conversion efficiency is about 0.1-1% for non-coherent pumping and up to about 80% with coherent pumping. Laser emission could be delivered to the treatment site by an optical waveguide, or, in other embodiments, a plurality of waveguides or laser media could be pumped by a plurality of laser sources (lamps) next to the treatment site. Such dye lasers can result in energy exposure up to several hundreds of J/cm2, pulse duration from picoseconds to tens of seconds, and a fill factor from about 0.1% to 90%.
Another example of a coherent source is a fiber laser. Fiber lasers are active waveguides a doped core or undoped core (Raman laser), with coherent or non-coherent pumping. Rare earth metal ions can be used as the doping material. The core and cladding materials can be quartz, glass or ceramic. The core diameter could be from microns to hundreds of microns. Pumping light could be launched into the core through the core facet or through cladding. The light conversion efficiency of such a fiber laser could be up to about 80% and the wavelength range can be from about 1,100 to 3,000 nm. A combination of different rare-earth ions, with or without additional Raman conversion, can provide simultaneous generation of different wavelengths, which could benefit treatment results. The range can be extended with the help of second harmonic generation (SHG) or optical parametric oscillator (OPO) optically connected to the fiber laser output. Fiber lasers can be combined into the bundle or can be used as a single fiber laser. The optical output can be directed to the target with the help of a variety of optical elements described below, or can be directly placed in contact with the skin with or without a protective/cooling interface window. Such fiber lasers can result in energy exposures of up to about several hundreds of J/cm2 and pulse durations from about picoseconds to tens of seconds.
Diode lasers can be used for the 400-100,000 nm range. Since many photodermatology applications require a high-power light source, the configurations described below using diode laser bars can be based upon about 10-100 W, 1-cm-long, cw diode laser bar. Note that other sources (e.g., LEDs and microlasers) can be substituted in the configurations described for use with diode laser bars with suitable modifications to the optical and mechanical sub-systems.
Other types of lasers (e.g., gas, excimer, etc.) can also be used.
2. Non-Coherent Light Sources
A variety of non-coherent sources of electromagnetic radiation (e.g., arc lamps, incandescence lamps, halogen lamps, light bulbs) can be used for the energy source 210. There are several monochromatic lamps available such as, for example, hollow cathode lamps (HCL) and electrodeless discharge lamps (EDL). HCL and EDL could generate emission lines from chemical elements. For example, sodium emits bright yellow light at 550 nm. The output emission could be concentrated on the target with reflectors and concentrators. Energy exposures up to about several tens of J/cm2, pulse durations from about picoseconds to tens of seconds, and fill factors of about 1% to 90% can be achieved.
Linear arc lamps use a plasma of noble gases overheated by pulsed electrical discharge as a light source. Commonly used gases are xenon, krypton and their mixtures, in different proportions. The filling pressure can be from about several torr to thousands of torr. The lamp envelope for the linear flash lamp can be made from fused silica, doped silica or glass, or sapphire. The emission bandwidth is about 180-2,500 nm for clear envelope, and could be modified with a proper choice of dopant ions inside the lamp envelope, dielectric coatings on the lamp envelope, absorptive filters, fluorescent converters, or a suitable combination of these approaches.
In some embodiments, a Xenon-filled linear flash lamp with a trapezoidal concentrator made from BK7 glass can be used. As set forth in some embodiments below, the distal end of the optical train can, for example, be an array of micro-prisms attached to the output face of the concentrator. The spectral range of EMR generated by such a lamp can be about 300-2000 nm, energy exposure can be up to about 1,000 J/cm2, and the pulse duration can be from about 0.1 ms to 10 s.
Incandescent lamps are one of the most common light sources and have an emission band from 300 to 4,000 nm at a filament temperature of about 2,500 C. The output emission can be concentrated on the target with reflectors and/or concentrators. Incandescent lamps can achieve energy exposures of up to about several hundreds of J/cm2and pulse durations from about seconds to tens of seconds.
Halogen tungsten lamps utilize the halogen cycle to extend the lifetime of the lamp and permit it to operate at an elevated filament temperature (up to about 3,500 C), which greatly improves optical output. The emission band of such a lamp is in the range of about 300 to 3,000 nm. The output emission can be concentrated on the target with reflectors and/or concentrators. Such lamps can achieve energy exposures of up to thousand of J/cm2 and pulse durations from about 0.2 seconds to continuous emission.
Light-emitting diodes (LEDs) that emit light in the 290-2,000 nm range can be used to cover wavelengths not directly accessible by diode lasers.
Referring again to
E. Alternate Embodiments of Optical Systems
Generally, optical system 212 of
If an optical system 212 is used, the energy of the applied light can be concentrated to deliver more energy to target portions 214. Depending on system parameters, portions 214 may have various shapes and depths as described above.
The optical system 212 as shown in
Where an acoustic, RF or other non-optical EMR source is used as energy source 210, the optical system 212 can be a suitable system for concentrating or focusing such EMR, for example a phased array, and the term “optical system” should be interpreted, where appropriate, to include such a system.
While as may be seen from Table C, depth d for volume V and the focal depth of optical system 212 are substantially the same when focusing to shallow depths, it is generally necessary in a scattering medium such as skin to focus to a greater depth, sometimes a substantially greater depth, in order to achieve a focus at a deeper depth d. The reason for this is that scattering prevents a tight focus from being achieved and results in the minimum spot size, and thus maximum energy concentration, for the focused beam being at a depth substantially above that at which the beam is focused. The focus depth can be selected to achieve a minimum spot size at the desired depth d based on the known characteristics of the skin.
Both scattering and absorption are wavelength dependent. Therefore, while for shallow depths a fairly wide band of wavelengths can be utilized while still achieving a focused beam, the deeper the focus depth, the more scattering and absorption become factors, and the narrower the band of wavelengths available at which a reasonable focus can be achieved. Table C indicates preferred wavelength bands for various depths, although acceptable, but less than optimal, results may be possible outside these bands.
Numerical aperture is a function of the angle 9 for the focused radiation beam 222 from optical device 212. It is preferable that this number, and thus the angle 9, be as large as possible so that the energy at portions 214 in volume V where radiation is concentrated is substantially greater than that at other points in volume V (and in region 220), thereby minimizing damage to tissue in region 220, and in portions of volume V other than portions 214, while still achieving the desired therapeutic effect in the portions 214 of volume V. Higher numerical aperture of the beam increases safety of the epidermis, but it is limited by scattering and absorption of higher incidence angle optical rays. As can be seen from Table C above, the possible numerical aperture decreases as the focus depth increases.
In the embodiment of
According to one embodiment, the output mirror 422 includes highly reflective portions 432 that provide feedback (or reflection) into the laser cavity. The output mirror 422 also includes highly transmissive portions 434, which function to produce multiple beams of light that irradiate the surface 438 of the patient's skin 440.
In one implementation, the output mirror 422 functions as a diffractive multi-spot sieve mirror. Such an output mirror 422 can also serve as a terminal or contact component of the optical system 420 to the surface 438 of the skin 440. In other embodiments, the output mirror 422 can be made from any reflective material.
Because of the higher refractive index of the illuminated tissue of the skin 440, divergence of the beams is reduced when it is coupled into the skin 440. In other embodiments, one or more optical elements (not shown) can be added to the mirror 422 in order to image the output of mirror 422 onto the surface of the skin 440. In this latter example, the output mirror 422 is usually held away from the skin surface 438 by a distance dictated by the imaging optical elements.
Proper choice of the laser cavity length L, operational wavelength X of the source 426, the gain g of the laser media 428, dimensions or diameter D of the transmissive portions 434 (i.e., if circular) in the output mirror 422, and the output coupler (if used) can help to produce output beams 436 with optimal properties for creating islets of treatment. For example, when D2/4λL<1, effective output beam diameter is made considerably smaller than D, achieving a size close to the system's wavelength λ of operation. This regime can be used to produce any type of treatment islets.
Typically, the operational wavelength ranges from about 0.29 μm to 100 μm and the incident fluence is in the range from 1 mJ/cm2 to 100 J/cm2. The effective heating pulse width can be in the range of less than 100 times the thermal relaxation time of a patterned compound (e.g., from 100 fsec to 1 sec).
In other embodiments, the chromophore layer is not used. Instead the wavelength of light is selected to directly create the pathways.
In one example, the spectrum of the light is in the range of or around the absorption peaks for water. These include, for example, 970 nm, 1200 nm, 1470 nm, 1900 nm, 2940 nm, and/or any wavelength >1800 nm. In other examples, the spectrum is tuned close to the absorption peaks for lipids, such as 0.92 μm, 1.2 μm, 1.7 μm, and/or 2.3 μm, and wavelengths like 3.4 μm, and longer or absorption peaks for proteins, such as keratin, or other endogenous tissue chromophores contained in the SC.
The wavelength can also be selected from the range in which this absorption coefficient is higher than 1 cm−1, such as higher than about 10 cm−1. Typically, the wavelength ranges from about 0.29 μm to 100 μm and the incident fluence is in the range from 1 mJ/cm2 to 1000 J/cm2. The effective heating pulse width is preferably less than 100×thermal relaxation time of the targeted chromophores (e.g., from 100 fsec to 1 sec).
The embodiment of
The hand piece 150 of the embodiment of
The coating of the output window 460 can have a number of openings (or holes or transmissive portions) 462, which reshape the output beam into a plurality of beamlets 464. The openings 464 can be coated with anti-reflective coatings, or can contain Fresnel or refractive lenses for angular beam shaping. The openings 464 do not necessarily have to be of circular shape, as depicted in
The device can contain a cooling implement 466 to provide active contact cooling to the treatment area. The cooling implement 466 can be, for example, a sapphire cooling plate that is cooled by a water manifold or the like built into the hand piece, as set forth above. In addition, any other type of cooling implement 466, such as those set forth above, can be used.
The device of the embodiment of
In some embodiments, the openings 462 in the output window 460 can be coated with phase-changing material, which changes its transparency as a result of temperature change. That is, the transparency of the openings 462 decreases when the temperature increases. Thus, overheating of skin 470 can be prevented by blocking the beamlets 474 with the decreased transparency of the openings 416.
In operation, the output window 460 is brought into contact with the treatment area 470 (i.e., the patient's skin). The light source 452 is then fired to output radiation from the hand piece. The openings 462 in the output window 462 form islets of treatment on the patient's skin 470.
The device of
The device of
In some embodiment, the coating, (such as, for example, a multilayer dielectric high reflective coating with lattice of transparent zones) can be coated directly on the contact cooling surface of a sapphire chilled bock. In such an embodiment, the entire sapphire block can be used as a cooling area, but the irradiated area is limited by the area of the transparent zones. Such an embodiment can be effective for a combination of LOI treatment with skin upper layer protection for deep dermal or fat treatments.
In another embodiment, where a laser source is used, the laser itself can have an output that is not uniform. For example, in such an embodiment, the laser itself can be surrounded by a reflector, which can be a high reflector. The reflector surrounding the laser, and in particular at the output end of the laser, can have areas that are less reflective than other areas. That is, the reflector in such an embodiment does not have uniform reflectivity. These areas can result in increased radiation output from the laser source in discrete areas (or holes). Thus, the reflector or mirror surrounding the laser can itself generated spatially modulated light as an output. The laser source can therefore be housed in a hand piece that has the laser source output close to the output from the hand piece. The hand piece can therefore be brought into close proximity to the skin and fired to create treatment islets.
F. Cooling Elements
As set forth above, the system 208 can also include a cooling element 215 to cool the surface of the skin 200 over treatment volume V. As shown in
The cooling element 215 can include a system for cooling the optical system (and hence the portion in contact with the skin) as well as a contact plate that touches the patient's skin when in use. The contact plate can be, for example, a flat plate, a series of conducting pipes, a sheathing blanket, or a series of channels for the passage of air, water, oil or other fluids or gases. Mixtures of these substances may also be used, such as a mixture of water and methanol. For example, in one embodiment, the cooling system can be a water-cooled contact plate. In another embodiment, the cooling mechanism may be a series of channels carrying a coolant fluid or a refrigerant fluid (for example, a cryogen), which channels are in contact with the patient's skin 200 or with a plate of the apparatus 208 that is in contact with the patient's skin. In yet another embodiment, the cooling system may comprise a water or refrigerant fluid (for example R134A) spray, a cool air spray or air flow across the surface of the patient's skin 200. In other embodiments, cooling may be accomplished through chemical reactions (for example, endothermic reactions), or through electronic cooling, such as Peltier cooling. In yet other embodiments, cooling mechanism 215 may have more than one type of coolant, or cooling mechanism 215 and/or contact plate may be absent, for example, in embodiments where the tissue is cooled passively or directly, for example, through a cryogenic or other suitable spray. Sensors or other monitoring devices may also be embedded in cooling mechanism 215 or other portions of the hand held device, for example, to monitor the temperature, or determine the degree of cooling required by the patient's skin 200, and may be manually or electronically controlled.
In certain cases, cooling mechanism 215 may be used to maintain the surface temperature of the patient's skin 200 at its normal temperature, which may be, for example, 37 or 32° C., depending on the type of tissue being heated. In other embodiments, cooling mechanism 215 may be used to decrease the temperature of the surface of the patient's skin 200 to a temperature below the normal temperature of that type of tissue. For example, cooling mechanism 215 may be able to decrease the surface temperature of tissue to, for example, a range between 25° C. and −5° C. In other embodiments, a plate can function as a heating plate in order to heat the patient's skin. Some embodiments can include a plate that can be used for cooling and heating.
A contact plate of the cooling element 215 may be made out of a suitable heat transfer material, and also, where the plate contacts the patient's skin 200, of a material having a good optical match with the tissue. Sapphire is an example of a suitable material for the contact plate. Where the contact plate has a high degree of thermal conductivity, it may allow cooling of the surface of the tissue by cooling mechanism 215. In other embodiments, contact plate may be an integral part of cooling mechanism 215, or may be absent. In some embodiments, such as shown in
In certain embodiments, various components of system 208 may require cooling. For example, in the embodiment shown in
Typically cooler 215 is activated before source 210 to pre-cool the patient's skin to a selected temperature below normal skin temperature, for example −5° C. to 10° C., to a depth of at least DE junction 206, and preferably to depth d to protect the entire skin region 220 above volume V. However, if pre-cooling extends for a period sufficient for the patient's skin to be cooled to a depth below the volume V, and in particular if cooling continues after the application of radiation begins, then heating will occur only in the radiated portions 214, each of which portions will be surrounded by cooled skin. Therefore, even if the duration of the applied radiation exceeds TRT for portions 214, heat from these portions will be contained and thermal damage will not occur beyond these portions. Further, while nerves may be stimulated in portions 214, the cooling of these nerves outside of portions 214 will, in addition to permitting tight control of damage volume, also block pain signals from being transmitted to the brain, thus permitting treatments to be effected with greater patient comfort, and in particular permitting radiation doses to be applied to effect a desired treatment which might not otherwise be possible because of the resulting pain experienced by the patient.
G. Other Devices for Producing a Multiplicity of Treated Islets
A number of different devices and structures can be used to spatially modulate and/or concentrate EMR in order to generate islets of treatment in the skin. For example, the devices can use reflection, refraction, interference, diffraction, and deflection of incident light to create treatment islets. A detailed explanation of such are provided in the related applications listed above that have been incorporated by reference in their entirety.
In other embodiments, spatially selective islets of treatment can be created by applying to the skin surface a desired pattern of a topical composition containing a preferentially absorbing exogenous chromophore. The chromophore can also be introduced into the tissue with a needle, for example, a micro needle as used for tattoos. In this case, the EMR energy may illuminate the entire skin surface where such pattern of topical composition has been applied. Upon application of appropriate EMR, the chromophores can heat up, thus creating islets of treatment in the skin. Alternatively, the EMR energy may be focused on the pattern of topical composition. A variety of substances can be used as chromophores including, but not limited to, carbon, metals (Au, Ag, Fe, etc.), organic dyes (Methylene Blue, Toluidine Blue, etc.), non-organic pigments, nanoparticles (such as fullerenes), nanoparticles with a shell, carbon fibers, etc. The desired pattern can be random and need not be regular or pre-determined. It can vary as a function of the skin condition at the desired treatment area and be generated ad hoc.
Some embodiments provide a film or substrate material with a lattice of dots, lines or other shapes, either on the surface of the film or embedded within the film, in which the dots, lines or other shapes include a chromophore appropriate to the EMR source. The dots, lines or other shapes may be the same or different sizes and different shapes may be included on the film.
The dots, lines or other shapes may be formed from a material that can be glued, welded or otherwise attached to the stratum corneum to create islets, and such attachment may be sufficient to allow the film to be removed from the skin while leaving the dots, lines or other shapes on the skin. For example, the dots, lines or other shapes may be formed of an ultraviolet curing compound such that when the film is applied to the skin and ultraviolet light is applied to the film, the dots, lines or other shapes are attached to the skin and the film may be removed prior to EMR energy being applied. In other cases, the dots, lines or other shapes may be formed of a suitable phase-changing material (e.g., albumin), which can be used for welding. In other cases, the film is not removed and the EMR energy is applied through the film.
In other methods, the dots, lines or other shapes may be manually applied to the skin individually or by spraying or other techniques. In other embodiments, the hand piece may apply the shapes to the skin prior to applying the EMR energy. As one example, the shapes may be contained in a lotion, gel, powder or other topical composition that is applied to the skin manually prior to using the hand piece to apply the EMR energy. Alternatively, the lotion is dispensed by the hand piece onto the skin prior to the hand piece delivering EMR energy. As another example, a film containing the shapes may be applied to the skin manually or by the hand held device (as for example a tape dispenser).
H. Controllers and Feedback Systems
Some embodiments can also include speed sensors, contact sensors, imaging arrays, and controllers to aid in various functions of applying EMR to the patient's skin. System 208 of
I. Creation of Lattices Using Non-Optical EMR Sources
The lattices can also be produced using non-optical sources. For example, ultrasound, microwave, radio frequency and low frequency or DC EMR sources can be used as energy sources to create lattices of EMR-treated islets. In addition, for treating tissue surfaces, the tissue surface can be directly contacted with heating elements in the pattern of the desired lattice. Also, various optical and/or non-optical sources can be combined, such as visible light, acoustic energy, ultrasound, and shockwaves (e.g., formed by the application or heat, acoustic energy, ultrasound or other forms of energy). In addition, the sources can be combined with various mechanical stimuli, such as a vacuum or vibrating mechanism, to improve and facilitate the treatment of tissue.
J. Motion Sensors and Scanning Devices
A number of different devices and structures can be used to generate islets of treatment in the skin.
In one embodiment, the applicator 282 includes a motion detector 294 that detects the scanning of the head 284 relative to the skin surface 296. This generated information is used by the islet pattern generator 288 to ensure that the desired fill factor or islet density and power is produced on the skin surface 296. For example, if the head 284 is scanned more quickly, the pattern generator responds by imprinting islets more quickly. The following description describes this embodiment, as well as other embodiments, in greater detail. Further, the following sections elaborate on the types of EMR sources that can be used with the applicator 282 and on the methods and structures that can be used to generate the islets of treatment.
According to one embodiment, an apparatus can include a light emitting assembly for applying optical energy to the target area of the patient's skin, a sensor for determining the speed of movement of the head portion across the target area of the patient's skin, and circuitry in communication with the sensor for controlling the optical energy in order to create islets of treatment. The circuitry can control, for example, pulsing of the optical energy source based on the speed of movement of the head portion across the skin in order to create islets of treatment. In another embodiment, the circuitry can control movement of the energy source within the apparatus based on the speed of movement of the head portion across the skin in order to treat certain areas of the skin, while not exposing other areas, in order to create islets of treatment.
A number of types of speed sensors can be used to measure the hand piece speed relative to the skin surface. For example, the speed sensor can be an optical mouse, a laser mouse, a wheel/optical encoder, or a capacitive imaging array combined with a flow algorithm similar to the one used in an optical mouse. A capacitive imaging array can be used to measure both hand piece speed and to create an image of the treated area. Capacitive imaging arrays are typically used for thumbprint authentication for security purposes. However, a capacitive imaging array can also be used to measure the hand piece speed across the skin surface. By acquiring capacitive images of the skin surface at a relatively high frame rate (for example, 100-2000 frames per second), a flow algorithm can be used to track the motion of certain features within the image and calculate speed.
In the embodiment of
In operation, the embodiment described above can be used to create a uniform matrix of treatment islets by manually moving a hand piece that includes a single diode laser bar (or multiple diode laser bars) across the skin surface and pulsing the laser at a rate proportional to the hand piece speed. For example, decreasing the time interval between laser pulses as the hand piece speed increases can be used to keep a constant matrix of lines of islets of treatment on the skin. Similarly, increasing the time interval between laser pulses as the hand piece speed decreases can be used to keep a constant matrix of lines of islets of treatment on the skin. The treatment head, including treatment window or light aperture of the hand piece, can be rotated to vary the spacing between islets of treatment in the direction orthogonal to hand piece movement.
In addition to measuring hand piece speed, the capacitive imaging arrays 350, 352 can also image the skin after the line of islets of treatment has been created in order to view the treatment results. Acquired images can be viewed in real time during treatment. The hand piece can include, for example, a display that shows the treatment area of the skin under the cooling plate. Alternatively, the acquired images can be stored in a computer for viewing after the treatment is complete. In some embodiments, the system can be configured to display images from both sensors, so that the hand piece can be moved either forward or backward.
In the configurations discussed above, the diode laser is used at a relatively low duty cycle because the laser is turned off in between islets of treatment. In some embodiments, the diode laser can be used more efficiently by keeping the diode laser on for a longer time, for example, if the of islets of treatment are lines instead of spots.
In the embodiment of
Another embodiment could include a speed sensor. In this embodiment, the hand piece is a non-coherent EMR source disposed within the housing of the hand piece. The non-coherent EMR source can be any of the types set forth above, including, for example, a linear flash lamp, an arc lamp, an incandescence lamp, or a halogen lamp. In one embodiment, the light source is a Xe-filled linear flash lamp. The hand piece can also include an optical reflector, one or more optical filters, and a light duct or concentrator. The optical reflector can serve to reflect and direct the light into the concentrator. The concentrator can be made from glass BK7, and can have a trapezoidal shape. In other embodiments, the concentrator can be made from different materials and its shape can vary. The concentrator can be used, for example, for homogenization of the beam. In some embodiments, the optical filter might not be used. If used, the filter can serve to filter out certain wavelengths of light from the EMR source. In addition, the optical reflector might not be used in some embodiments. In some embodiments, a cooling plate can be attached to the housing or at the end of the optical path in order to cool the patient's skin.
The housing can be equipped with a speed sensor. This speed sensor can measure the speed of movement of the housing with respect to the patient's skin. In the embodiment of, the housing of the hand piece is capable of movement independently from the light source within the housing. That is, when the housing moves with a speed V with respect to the patient's skin, the light source can move within the housing such that the light source remains fixed with respect to the patient's skin. That is, the speed v of the light source with respect to the patient's skin is approximately zero, which means that the light source would move relative to the housing and within the housing at a speed of −V. In this embodiment, the light source does not move and is held steady during application of radiation in order to guarantee the desired energy exposure. When treatment of the selected part of skin has been completed, the light source can move within the housing in order to reach its initial position. That is, the light source can move forward in a leap-frog manner with a speed v>V (where both v and V are measured relative to the patient's skin) for treatment of the next part of skin.
As set forth above, for synchronization of the speed V of the housing and the speed v of the light source, the housing is equipped with the speed sensor. The speed sensor can measure the movement of the housing with respect to the patient's skin and then move the light source within the housing at an appropriate speed in order to remain fixed with respect to the patient's skin. The hand piece or a base unit associated with the hand piece can include circuitry that receives the speed of movement of the housing and then sends a signal to a motor that moves the light source 404 within the housing 402 at an appropriate speed. The hand piece, therefore, can include a linear motor or linear translator, such as those set forth above, to move the light source within the housing.
The description above indicates that the light source 404 is moveable within the housing The reflector, the filter, and the concentrator, if used, can be connected to the light source in some embodiments in a manner so that these components move within the housing 402 along with the light source.
In some embodiments using a Xe-filled linear flash lamp, the spectral range of the EMR is 300-3000 nm, the energy exposure up to 1000 J/cm2, the pulse duration is from about 0.1 ms to 10 s, and the fill factor is about 1% to 90%.
Another embodiment involves the use of imaging optics to image the patient's skin and use that information to determine medication application rates, application of EMR, or the like in order to optimize performance. For instance, some medical or cosmetic skin treatments require that the medication application rate be accurately measured and its effect be analyzed in real time. The skin surface imaging system can detect the size of reversible or irreversible holes created with techniques proposed in this specification for creating treatment islets in the stratum corneum. For this purpose, a capacitive imaging array can be used in combination with an image enhancing lotion and a specially optimized navigation/image processing algorithm to measure and control the application rate.
The use of a capacitive imaging array is set forth above in connection with
One example of a suitable capacitive sensor for this embodiment is a sensor having an array of 8 image-sensing rows by 212 image-sensing columns. Due to inherent limitations of capacitive array technology, a typical capacitive array sensor is capable of processing about 2000 images per second. To allow for processing skin images in real time, an orientation of the sensor can be selected to aid in functionality. In one embodiment, for instance, the images are acquired and processed along the columns. This allows for accurate measurement of velocity up to about 200 mm/s.
For the sensor to function reliably and accurately, the skin surface can be treated with an appropriate lotion. In some embodiments, a properly selected lotion can improve the light-based skin treatment and navigation sensor operation. A lotion may be optically transparent to the selected wavelength, provide image enhancement to a sensor, and function as a friction reduction lubricant.
Circuitry containing a processing algorithm or the like can be in communication with the capacitive image sensor. The capacitive sensor and its associated processing algorithm are capable of determining a type of lotion and its effect on the skin surface. This can be performed in real time by sequentially analyzing the image spectral characteristics. The processing algorithm can also perform sensor calibration, image contrast enhancement, and filtering, as well as processing and control of images of the skin surface with navigation code to aid in various applications.
Real time acquired images can be used for statistical analysis of a marker concentration in a lotion. The markers are put in a lotion to function as identifiers of a treatment area. The marker can be a chromophore itself (i.e., a chromophore that heats up upon application of irradiation) or it can be a chemical that indicates the presence of the chromophore or medication in the lotion. As one example, the marker emits or reflects light proportional to the incident light to indicate the concentration of a chromophore or medication in the lotion. The capacitive sensor, therefore, can function to determine whether the marker concentration of a given lotion is at an appropriate level. The circuitry can, for instance, send a signal to the user of the concentration of the marker. Alternatively, the circuitry can determine if the marker concentration meets a preselected set point concentration level for a certain marker. If the set point is not met, the circuitry can communication to the user to let the user know that more (or perhaps less) lotion may be needed on the patient's skin. Selected markers with the right lotion pH level can also be used as an eye safety enhancement feature for light treatment on human body.
The sensor can also function as a contact sensor. This allows for real time determination of immediate contact of a hand piece with the patient's skin. The combination of hardware and software allows this determination within one image frame. The algorithm measures in real time a skin contact and navigation parameters (position, velocity and acceleration) along the x-axis and y-axis. This enhances the safety of light treatment on human skin by allowing for the control of the velocity and the quality of skin contact. The quality of contact can be a function of lotion type and pressure applied to the treatment device.
The capacitive sensor along with image processing and special lotion can be used for detecting a skin imperfection and measuring its size in real time. The resolution of the sensor will depend on pixel size, image processing and the sub pixel sampling.
The capacitive sensor and image processing allow for determination of whether the device is operating on biological skin or some form of other surface. It is possible under proper sampling conditions to extract the type of skin the device is moving across. This is accomplished by comparing real time processed images to a stored pattern or calculated set of parameters. In addition, the combination of the capacitive sensor and image pattern recognition, navigation algorithm, and special lotion, can be used to determine the presence of skin hair and provide statistical information about the density and size of the hair.
The capacitive sensor with a combination of two types of lotion, a calibrated skin penetration lotion and image enhancing lotion, can determine the effect of skin rejuvenation on skin over a large area. This analysis can be performed in real time by treating the skin with two lotions and then moving the capacitive sensor over the skin area of interest. The real time algorithm determines the effective area of treatment and the enhancement factor above the norm.
K. Hand Piece with Diode Laser Bar
Some embodiments use one or more diode laser bars as the EMR source. Because many photodermatology applications require a high-power light source, a standard 40-W, 1-cm-long, cw diode laser bar can be used in some embodiments. Any suitable diode laser bar can be used including, for example, 10-100 W diode laser bars. A number of types of diode lasers, such as those set forth above, can be used. Other sources (e.g., LEDs and diode lasers with SHG) can be substituted for the diode laser bar with suitable modifications to the optical and mechanical sub-systems.
The diode laser bar 315 can be, in one embodiment, ten to fifty emitters (having widths of 50-to-150 μm in some embodiments or 100-to-150 μm in others) that are located along a 1-cm long diode bar with spacing of 50 to 900 μm. In other embodiments, greater than or less than fifty emitters can be located on the diode laser bar 315, the emitter spacing, and the length of the diode laser bar 315 can also vary. In addition, the width of the emitters can vary. The emitter spacing and the number of emitters can be customized during the manufacturing process.
The diode laser bar 315 can be, in one embodiment, twenty-five 100-to-150 μm or 50-to-150 μm wide emitters that are located along a 1 cm long diode bar, each separated by around 50 to 900 microns in some embodiments, and approximately 500 microns in others.
In the embodiment of
Referring again to
In operation, one way to create islets of treatment is to place the housing 313, including the diode laser bar 315, in close proximity to the skin, and then fire the laser. Wavelengths near 1750-2000 nm and in the 1400-1600 nm range can be used for creating subsurface islets of treatment with minimal effect on the epidermis due to high water absorption. Wavelengths in the 290-10,000 can be used in some embodiments, while in other wavelengths in the 900-10,000 nm range can be used for creating surface and subsurface islets on the skin. Without moving the hand piece across the skin, a series of treatment islets along a line can be formed in the skin.
In another embodiment, the user can simply place the hand piece in contact with the target skin area and move the hand piece over the skin while the diode laser is continuously fired to create a series of lines of treatment. For example, using the diode laser bar 330 of
In another embodiment, an optical fiber can couple to the output of each emitter of the diode laser bar. In such an embodiment, the diode laser bar need not be as close to the skin during use. The optical fibers can, instead, couple the light from the emitters to the plate that will be in close proximity to the skin when in use.
In operation, the hand piece 310 of
During operation, the user of the hand piece 310 of
In addition to the embodiments set forth above in which the diode laser bar(s) is located close to the skin surface to create islets of treatment, a variety of optical systems can be used to couple light from the diode laser bar to the skin. For example, with reference to
Another embodiment is depicted in
In operation, by incorporating more than one diffractive optics 330 in the hand piece 310 along with a motor 334 for moving the different diffractive optics 330 between the stack 325 of diode laser bars and the plate 317, the diffractive optics 330 can be moved in position between the stack 325 and the cooling plate 317 in order to focus the energy into different patterns. Thus, in such an embodiment, the user is able to choose from a number of different islets of treatment patterns in the skin through the use of the same hand piece 310. In order to use this embodiment, the user can manually place the hand piece 310 on the target area of the skin prior to firing, similar to the embodiments described earlier. In other embodiments, the hand piece aperture need not tough the skin. In such an embodiment, the hand piece may include a stand off mechanism (not shown) for establishing a predetermined distance between the hand piece aperture and the skin surface.
In the embodiment of
As an example of an application of a diode laser bar to create thermal damage zones in the epidermis of human skin, a diode laser bar assembly, as depicted in
N. Solid State Laser Embodiments
In the exemplary embodiment as in
In one embodiment, an optical element 630, such as a lens array, can be used to direct and output the EMR from the fiber bundle 624 in order to focus the EMR onto the patient's skin 632. The optical element 630 can be any suitable element or an array of elements (such as lenses or micro lenses) for focusing EMR. In the embodiment of
In operation, the laser source 620 generates EMR and the reflector 626 reflects some of it back toward the output coupler 628. The EMR then passes through the output coupler 628 to the optical lens 622, which directs and focuses the EMR into the fiber bundle 624. The micro lens array 630 at the end of the fiber bundle 624 focuses the EMR onto the patient's skin 632.
The embodiment of
In operation, the laser source 620 generates EMR and the reflector 626 reflects some of it back toward the output coupler 628. The EMR then passes through the output coupler 628 to the phase mask 640, which spatially modulates the radiation. The optical element 642, which is optically downstream from the phase mask 640 so that it receives output EMR from the phase mask 640, generates an image of the apertures on the patient's skin.
In the embodiment of
In operation, the bundle of lasers 650 generate EMR. The EMR is spatially modulated by spacing apart the laser sources 650 as shown in
In the exemplary embodiment of
O. Consumer-Oriented Products and Methods
Other embodiments can be used in consumer devices as well as professional devices, depending on the application.
A. Applications Generally
When a micro-hole is created in tissue in vivo, healing processes will cause the micro-holes to heal and, if open through the surface, close. If the micro-hole extends from the surface of skin tissue and into the tissue, the time required to close the micro-hole is roughly proportional to the diameter of the opening of the micro-hole at the surface. A smaller opening will heal more quickly, and a larger hole will take longer to heal.
The closure of the micro-holes provides benefits such as protection from infection. Thus, a quickly closed hole can help reduce the chances of infection as compared to a larger hole that is open longer. A treatment that employs relatively smaller holes, therefore, can provide safety benefits over similar procedures using larger holes. If the hole is small enough, a fairly aggressive ablative skin-rejuvenation or other procedure (for example, a procedure having a high density of micro-holes or deep micro-holes or both) can be performed on a person with minimal risk of infection, because, as demonstrated in
Generally, by using smaller micro-holes during treatments, the overall healing time is reduced. This has many potential treatment benefits, such as allowing the person treated to return for additional rounds of treatment sooner, and completing a course of treatment more quickly. Unlike currently available treatments, the faster closure of the micro-holes also allows the person treated to resume regular activities such as applying cosmetics or swimming, in some cases within less than a day.
In some embodiments, micro-structures that result in a sterile or semi-sterile environment are possible. For example, micro-holes that are too small to pass certain foreign substances are possible. Additionally, in some embodiments, the ablative process may result in heat transfer to tissue surrounding the micro-structure or forming the wall of the micro-structure, and that tissue may shrink as a result of the heating, further decreasing the size of the micro-structure and contributing to the fast healing time.
Similarly, in other embodiments, the micro-structures may result in a bloodless wound or may restrict blood loss. For example, micro-holes may be created that are too small for blood to escape or are so small that blood loss is minimal.
Additionally, micro-holes can be used in many other applications, including without limitation:
Many other applications and uses are possible. The following sections provide additional detailed description of several exemplary applications.
B. Skin Rejuvenation and Tightening Using Micro-Grooves.
By forming an array of micro-grooves in the skin, skin can be tightened, rejuvenated, and wrinkles (both deep and superficial), fine lines and rhytides can be eliminated from the skin. By removing a percentage of the tissue in a treatment area (e.g., 30%-40% of the tissue measured by volume or surface area), significantly less tissue remains in the treatment area after ablation than prior to ablation. Thus, tissue can be tightened or reshaped by at least two methods. First, the natural healing processes associated with the tissue, such as skin tissue. Second, additional mechanical manipulation of the tissue. Furthermore, the process can be used to improve the micro-texture of the tissue.
For example, referring to
The treated areas of tissue can then be reshaped. For example, for skin tissue, the treated areas can be manipulated to tighten the skin or lift the skin or otherwise reshape the skin. Ablated grooves can also be used to reduce the area of skin tissue following various invasive procedures, such as liposuction.
Using arrays of micro-grooves to tighten tissue has several advantages in some applications over both ablative and non-ablative fractional techniques. For example, for wrinkle removal, forming EMR-treatment islets in the form of an array of circular islands of damage does not alter the structural integrity of the tissue. Thus, such methods rely on the healing response alone to remove the wrinkle. By ablating grooves of tissue from the skin, however, the healing response is still achieved, and the integrity of the tissue in which the wrinkle resides is altered such that it can be mechanically altered to better remove the wrinkle. Further, in the case of micro-grooves or similar micro-structures, there is no bulk damage to any portion of the tissue but a portion of the epidermis is damaged, which may improve the results when compared to non-ablative, non-fractional techniques for wrinkle removal.
Additional methods may combine the use of micro-grooves or other micro-structures with the use of an injected muscle management substance such as Botulinum Toxin Type A (e.g., Botox®), or other similar substances. Using micro-grooves in combination with the application of such substances increases the length of the effect of the treatment when compared to the application of Botox® alone. Additionally, such muscle management substances can decrease the stress and/or tension on the treated skin tissue during the healing process to produce a better result.
In addition to mechanically manipulating tissue, a subject being treated can be positioned to allow gravity to stretch the skin prior to treatment, such as lying face up or with the top of the head tilted at a downward angle when treating the face and/or neck.
C. Ablation Islets For Skin Rejuvenation and Wrinkle Removal
Skin rejuvenation as well as the removal of wrinkles, fine lines and rhytides can be accomplished by other embodiments in addition to the embodiments involving grooves above. For example, the healing process resulting from an array of ablated micro-holes will produce rejuvenated skin, such as skin with fewer age spots or other pigmented lesions and skin with smoother texture. The healing process will also reduce the number and degree of wrinkles, fine lines and rhytides.
Fractional ablative methods may have one or more advantages over existing non-ablative skin rejuvenation and wrinkle removal techniques, including, without limitation, less pain, shorter down time, higher safety margins, deeper treatments, and improved results. Exemplary treatments of the eyelids, upper lip, acne scarring and peri-orbital wrinkles are performed using an Er:YSGG laser at 2790 nm with a pulse width of 2 or 5 ms and a fluence of 6-9 mJ per beam. Alternatively, an Er:YAG laser with a wavelengths of 2940 nm, a pulsewidth of 300 μm, and a fluence of 3-6 mJ per beam can be used. (See Table B for additional associated parameters.) Using the parameters of Table B above, multiple passes may be preferable, e.g., 6 passes with passes 1-2 at a fluence of 5 mJ/beam, and passes 3-6 at a reduced fluence 3 mJ/beam. Many other combinations of parameters are possible for skin rejuvenation, wrinkle removal, and other applications.
Additionally, skin rejuvenation and wrinkle removal can be achieved by the targeted stimulation of hyaluronic acid in skin tissue. The creation of lattices of micro-holes can result in the promotion of production of hyaluronic acid as a result of the healing response of tissues to thermal stress or thermal shock (short- to medium-term effect). Repeating treatments in regular intervals can maintain the level of hyaluronic acid and as a result maintain improved skin appearance.
In some embodiments, skin rejuvenation may result from the introduction of certain types of fillers that enhance the mechanical and optical properties of the tissue. These embodiments are discussed in greater detail below.
D. Delivery, Absorption and Extraction of Substances Through Micro-Structures
Substances can be extracted or delivered using various methods, including absorption, vibration, other mechanical stimulation (such as massaging of the tissue or applying positive or negative pressure), applying electrical or magnetic fields, application of a jet spray and application of acoustic energy such as ultrasound. For example, a magnetic field can be applied to magnetized particles that are then forced into the micro-holes or that or pulled from the micro-holes. Additionally, a chromophore in the micro-holes or delivered via the micro-holes can be heated using the magnetic field or other energy rather than using EMR. Substances can be delivered as solids, liquids, and particulates and crystals applied as part of a jet spray system. The substances can be elements, compounds, mixtures, compositions, suspensions, and may include components in different phases, such as small solid particulates in a liquid. When introduced into a cavity of a micro-structure, the substance can remain in the micro-structure or disburse into the tissue, e.g., by dissolving, transportation across membranes in the tissue, or other means.
1. Tissue Permeability
Referring to
where Psc, PE, and PD are the permeability coefficients for the agent diffusing through the sin respectively for SC, epidermis, dermis.
Because all three skin layers are perforated by an erbium laser, all three permeation coefficients may be presented in the form assuming that each permeability coefficient is the summation of a normal pathway (0) and a pore pathway (p) weighted by the pores filling factor ƒj
i=0, p and j=SC, E, D: Dji for i=0 is the diffusion coefficient of an agent in the corresponding intact part of tissue layer, and for i=p is the diffusion coefficient of this agent in the corresponding damaged part of tissue layer; hj is the thickness of the skin layer; dj is the diameter of a circular micro-structure (in this case a micro-hole); Nj is the number of such micro-structures with a skin surface area S. Thus, to estimate skin permeation when perforated with an erbium laser, it follows that:
For simplicity, all micro-holes are presumed to be of the equal diameter and running without change of their diameter through all three skin layers, i.e., fi=f; and the diffusion coefficient of the agent (a) along a micro-hole crossing all skin layers is equal to its diffusion in water Djp=Dwa. Thus, f for laser damaging should be in the range of 0.01-0.2. The permeability of intact stratum corneum is a few orders less than water for any agent. For example for small molecules, such as glycerol, propylene glycol, diffusion coefficient in stratum corneum is close to water diffusivity in the stratum corneum, i.e., Da=3×10−10 cm2/s. For living epidermis the typical diffusivity of a number of agents is of Da=3×10−8 cm2/s. Two orders higher diffusivity of the living epidermis in comparison with the stratum corneum is due to a more permeation ability of epidermal cell membrane, which is similar to permeability of membranes of other epithelial cells. For dermis the diffusivity is approximately equal to diffusivity of any fibrous tissue, Da=3×10−6 cm2/s, that is close to diffusivity of small molecules in water.
Accounting for above estimations, permeability is approximated by the following equations:
Substituting these approximate equations into the equation (11) above gives the following:
The typical values of the human skin layers thicknesses are the following hSC≈10-20 μm, hE≈100-200 μm, and hD≈1000-2000 μm. Thus, for thick skin perforated with a high filling factor, not less than 0.1, the total skin permeability is defined by dermis only. For the small filling factors, of 0.01 and less, and rather thin dermis layer, the total skin permeation is proportional to the filling factor and depends inversely on thicknesses of stratum corneum and epidermis. This formula qualitatively describes the experimental fact that permeation of laser ablated skin can be saturated when the percentage of the ablated area is approximately 13%.
As an example, using a low molecular weight compound, the total permeability significantly increases for skin containing micro-holes in comparison with intact skin: 54 fold for thin skin; 43 fold for medium thickness skin, and 31 fold for thick skin models when filling factor changes from 0 to 0.01. Because dermal thickness dominates for all skin models and agent's diffusivity in intact dermis is only one order less than in water the total permeability increases approximately equally, 10.7-11.5-fold, with a fill factor increase from 0.01 to 1.
Based on the above analysis, all of the methods of physical deliver described herein, such as iontophoresis, sonophoresis, electroosmosis, laser-induced pressure waves, and topical application of alcohol, and other chemical permeation enhancers can be used in combination with the formation of micro-structures in the skin. Similarly, the existence of a micro-hole or other micro-structure in the skin will allow various physical techniques such as mechanical compression, stretching, and/or fast flow sprays may, to be used to deliver particles, suspensions of particles, and other substances and compositions into the skin.
Following delivery of a substance, including fillers, chromophores, drugs and other substances, an occlusive bandage, or other barrier, can be fixed to the tissue to retain the substance within the micro-voids and/or to reduce or prevent vapor exchange through the tissue.
E. Delivery of Chromophores
As noted above, the micro-holes can be used to deliver a chromophore into tissue. Subsequently, the chromophore is selectively heated using EMR or other energy. As a result, the tissue, organ, gland or other structure adjacent to the chromophore can be ablated, damaged or otherwise altered. Use of chromophores delivered through micro-holes may have several advantages over selective photothermolysis at it is presently practiced or other present treatments and methods. For example, by delivering a chromophore into the tissue, a chromophore that has a very high contrast with the surrounding tissue can be chosen, such that the chromophore absorbs EMR at a given wavelength far more readily than a chromophore that may already be present in the tissue. Thus, the chromophore will require much less energy to absorb the same amount of heat as, for example, a naturally occurring chromophore. Therefore, less energy will be required to achieve the same result. Thus, the treatment may be less painful, and may be capable of being performed without cooling. The contrast between the applied chromophore and the tissue can be further accentuated by first increasing the translucence of the tissue by infusing a substance such as glycerol into the micro-holes (or into a different set of micro-holes). Generally, a higher contrast in the degree of absorption of energy at a given wavelength or wavelengths by the chromophore as compared to the treated tissue, will allow the tissue to be successfully treated using relatively less energy.
In other embodiments, several different chromophores could be applied after the creation of a set of micro-holes. If each chromophore had complimentary coefficients of absorption and/or were preferentially absorbed (or not absorbed) by various tissues, a first chromophore could be irradiated with a wavelength(s) of EMR that was not readily absorbed by the second chromophore and that did not disturb the second chromophore. Thus, several successive treatments could be performed without the need to retreat the tissue to create a new set of micro-holes to introduce the second chromophore at a later time. Similarly, in some embodiments, two different tissue, tissue structures or tissue organs could be treated using different chromophores. Many other various of such types of treatments are possible.
By way of example, chromophores can be introduced into skin tissue to treat sebaceous glands (e.g., to treat acne) or to treat subcutaneous tissue (e.g., for fat reduction or to treat cellulite). In the case of acne, micro-holes can be formed to a depth of approximately 0.5-1.0 mm in the surface of affected skin tissue. A chromophore (e.g., carbon particles, can be placed in the micro-holes. Subsequently, EMR is applied to the chromophore. It is preferable, but not essential, that the EMR have a wavelength corresponding approximately to a high or maximum coefficient of absorption of the chromophore and a low or minimum coefficient of absorption of the surrounding tissue. For example, EMR having one or more wavelengths in the range of 800 nm-1200 nm could be used.
To treat subcutaneous tissue, micro-holes can be formed to a depth of approximately 3.0 mm from the surface and into the affected tissue. Referring to
In other embodiments, a chromophore can be delivered throughout an area of the dermis for a particular treatment, for example, hair removal or permanent hair reduction by delivering energy to the chromophore to destroy or impair the function of a hair follicle. Alternatively, the chromophore could be delivered locally within the dermis to treat a particular volume or structure. For example, micro-holes could be created in the area of a pigmented or vascular lesion to the depth of the lesion, preferably to the depth of the lower boundary of the lesion. A chromophore such as carbon can then be delivered through the holes. The chromophore can remain within the holes or, in other embodiments, the chromophore (or a composition containing the chromophore) could be allowed to diffuse into the lesion or other structure being treated. Subsequently, the volume of tissue containing the chromophore is irradiated to heat the chromophore and cause localized tissue damage to the lesion, thereby removing the lesion during the healing process.
The above descriptions are exemplary only. Many other embodiments are possible.
F. Delivery of Fillers and Non-Drugs
In addition to drugs, micro-islets and other micro-structures can be used to deliver bio-inert materials such as fillers. For example, micro-holes, micro-cavities, micro-grooves and other micro-structures can be used to apply a filler to, for example, alter a physical or mechanical property of the skin.
By controlling the depth and fill factor of the micro-holes, micro-channels or other micro-structures, the fillers and other bio-inert materials can be introduced evenly across and throughout the skin tissue as desired. Such procedures allow for the delivery of substances to precise depths, which are not typically possible using other methods, such as delivery of substances with needles. Such fillers can, for example, be applied using pressure applied from a gun or other handpiece to saturate the treated columns or fill any holes or pits.
Substances that are not readily absorbed into the body and/or that are not metabolized or eliminated can also be used. Examples of such substances include tattoo ink, cosmetics, and substances capable of providing ultraviolet (“UV”) protection. Such substances may remain embedded indefinitely and, therefore, provide essentially a permanent or semi-permanent tattoo, cosmetic or UV protection. Other permanent, semi-permanent or temporary substances can be embedded in the micro-holes. Such fillers can further include organic materials such as fat. Exemplary substances that can be used include titanium oxide, aluminum oxide (sapphire), silicon oxide, diamond, quartz, silica, zirconium oxide, hydroxylanitite, apatite, silver, gold, polymethyl methacrylate, other acrylics, other glasses, carbon black, magnetic nanoparticles, nanoshells, fullerens, astrolens, porous silicon, and hyaluronic acid fillers (such as Perlane and Restylane) can be used to alter the optical and mechanical properties of the skin. Many other substances are possible.
Fillers can be used to change the appearance of the skin and to increase scattering or absorption properties, for example to alter the skin's luminescence and reflectance. Fillers can also be used to alter the elasticity and tightness of the skin and can be used to plump certain tissues. In some embodiments, particles or compositions of particles having a refractive index of between 1.5 and 3.0 can be delivered into skin tissue to alter the optical properties of the skin. For example, sapphire has an index of refraction of approximately 2.4 which is much higher than that of skin. Thus, sapphire may be used cosmetically to alter the overall refraction of skin tissue. Additionally, skin whitening and volumetric brightening (improvement of skin albedo) can be achieved by delivering substances having a relatively high refractive index.
In another embodiment, referring to
Similar principles can be applied to block other visible structures in the skin, such as lesions or variations in skin tone. Generally, by increasing the scattering, reflectance, and/or the fluorescence of the tissue, the radiancy of the tissue will be increased and structures in the tissue can be obscured and/or smoothed. Conversely, decreasing the scattering, reflectance, and/or the fluorescence can cause the tissue to become more translucent. In the later case, skin that is more translucent and/or transmissive to some or all wavelengths of EMR can be useful for diagnostic purposes. For example, by greatly reducing the scattering of the tissue, the tissue may be imaged or EMR can otherwise be applied for diagnostic purposes and much deeper layers of tissue can be effectively accessed for such purposes.
Micro-islets can be used to deliver a permanent or semi-permanent sunscreen. For example, referring to
Referring to
The permanent and semi-permanent sunscreens are not applied to the entire area of the skin tissue, and thus, do not provide complete protection to the tissue. However, the protection may be superior to currently used topical lotions and sprays due to the very thin layers of protection (several microns in thickness) provided by topical sunscreens. Furthermore, topically applied sunscreens may not adequately protect skin tissue due to 1) reduction of light scattering in the stratum corneum due to optical immersion and 2) inhomogeneous distribution of the topically applied substances. (See J. Lademann, A. Rudolph, U. Jacobi, H.-J. Weigmann, H. Schaefer, W. Sterry, and M. Meinke “Influence of Nonhomogeneous Distribution of Topically Applied UV Filters on Sun Protection Factors,” J Biomed. Opt., vol. 9, 2004, pp. 1358-1362). Both effects lead to reduction in the efficacy of topical sunscreen, because there are fewer interactions of migrating photons in skin with sunscreen material when there is less scattering, and also because areas free or nearly free of sunscreen do not block ultraviolet radiation.
Thus, although the protection is not completely applied across the entire skin surface, it provides an added degree of protection that may be superior to topicals, due to, among other things, the increase in scattering that promotes absorption by the sunscreen filler material. Additionally, these methods may be combined with standard application of topicals, to provide even greater protection, while still providing protection when a topical has not been applied.
In other embodiments, nanoparticles can be delivered into the tissue to allow the particles to be used within the tissue. The nanoparticles can be tuned to be responsive to particular wavelengths.
Referring to
The substances that are delivered can be used for skin rejuvenation, hydration and similar treatments. For example, delivery of antioxidant preparations (alfa-hydroxy acids) that leads to additional skin hydration can provide enhanced dead keratinocyte exfoliation, and, thus, to improvement of mechanical properties of skin (elasticity and softness) and smooth profile. Similarly, cosmetic hydration fillings for keratin and collagen hydration can improve mechanical properties of skin (elasticity and softness). Macromolecular fillings (e.g., collagen, elastin, protoglycans, and etc.) can also improve mechanical properties of skin (elasticity and softness).
In other embodiments, other substances can be applied for different purposes. For example, skin color can be improved by delivering skin lightening complexes, such as Bright Idea™ Artistry lightening complex. Collagen growth can be stimulated using internal cosmetics such as Rejuva™. Skin moisture and elasticity can be enhanced by delivering chondrotin sulfate to maintain skin moisture and elasticity.
An ink can be delivered to form a permanent or temporary tattoo. The lattices can also be created to control tattooing of tissue. For examples, holes bearing different color pigments can be created. Similarly, a reversible tattoo can be created using magnetized particles is possible.
G. Absorption and Delivery of Drugs
As in the embodiments that create micro-holes in nail tissue, micro-holes can similarly be used to facilitate the delivery of drugs or other substances through the skin or other soft tissues. For example, a mixture containing a drug (or drugs) and/or other substances having low absorption rates can be applied to the surface of the skin in an area that has been treated with EMR to create and array of micro-holes. Treatments according to this embodiment may involve treatments of one or more different anatomical sites of human body, such arms, legs, forehead, axilla, etc., and multiple target sites or tissue types can be treated simultaneously.
Presently, many potential therapies for the treatment of skin or some other superficial organ diseases are declined due to the toxic effect of drugs taken orally, by injection or intravenously. Similarly, many approved painkillers are also taken orally, by injection, intravenously, or superficially on a daily (or even hourly) basis for the treatment of skin or other superficial organ pain. Applying the treatment substance having a low dissolving rate inside a human body has been successfully used for the treatment of long lasting pain or for preventative purposes. In most such cases, the substance is a matrix of tablets, which dissolve slowly and release embedded medicine to maintain the necessary concentration locally.
Such treatment substances having a low dissolving rate can be applied to micro-holes, such as micro channels, for the treatment of human skin and other diseases. The uptake of the treatment substance can be enhanced by embedding the substance within the micro-holes using chemical enhancers (e.g., polar solvents (such as decylmethylsulfoxide) and polyenic antibiotics (to enhance membrane permeability), mechanical or other energy, for example, positive and/or negative pressure, magnetic fields applied to magnetic substances, electric fields applied to electrically charged substances (e.g., iontophoresis), local skin heating, massage or other mechanical manipulation of the tissue, sprays (e.g., high pressure sprays with small droplets) light waves or other EMR-induced stress, acoustic waves including sonophoresis and other forms of ultrasound, . The treatment method may involve (but would not necessarily be limited to) one or more steps of treatment with single wavelengths, and may also be applied in the course of two or more repetitions of the treatment procedure in one or more treatment sessions. Multiple wavelengths may also be used, depending on the application, which may be applied using the same or different light sources.
Many substances can be used, including, for example, pure substances, mixtures containing one or more active compounds; and compounds in an active or inactive matrix. The substance applied can be in various forms, including, without limitation, liquid, solid, gel or aerosol forms.
Drugs or other substances having high absorption rates can also be applied, but the mechanism is presently thought to work more beneficially with drugs having a low absorption rate. Furthermore, in other embodiments, a substance normally having a high dissolving rate can be applied slowly, because the dissolving rate can be dictated by the active ingredients and/or inactive ingredients. Thus, a mixture having a low dissolving rate can be manufactured to include an ingredient that normally has a high dissolving rate.
In some embodiments, the treatments involve three steps. First, micro-holes are created in the tissue, such as human skin. The micro-holes are created at the selected anatomical location using a device similar to device 500 as shown in
Second, the substance is embedded in the micro-holes. This step can be performed by various methods, including, without limitation, simple diffusion, vesicle/particle transporters, physical mechanisms, chemicals, or electrical mechanisms, electroporation, iontoporation, sonophoresis, magnetophoresis, photomechanical waves, niosomes, and transfersomes.
Third, the substance is sealed within the micro hole. This can be accomplished by various methods, including, without limitation, natural healing, healing creams, covering with, e.g., tapes or strips, and sutures.
The process may need to be repeated several times depending on the application.
Many embodiments are possible, including variations of parameters used. Furthermore, the substance embedded in the micro hole need not be a drug.
To examine the efficacy of using micro-holes to embed substances within tissue, several experiments were performed which demonstrate the successful application of substances into micro-holes in tissue.
1. Experiment 1—Creating an Open Hole in the Human Skin in vivo
Less energy is required to create micro-holes in the human skin than is required to make similarly sized micro-holes in nail tissue. Approximately, 5 mj per beam is enough energy to make holes traversing through the epidermis. In this case, the treatment was performed on the subject's right arm in vivo. The treatment parameters were: a wavelength of 2940 nm at 5.5 milijoules per beam, using a single pulse of 200 microseconds. As a result of the treatment, the subject experienced a similar sensation after applying a 10% ammonia solution as that described in conjunction with Experiment 4 above. The burning sensation indicates that hole went through the stratum corneum. Referring to
2. Experiment 2—Treatment of Tissue Using 2940 nm and a Pitch of 330 μm
In the following experiment, a sample of Yucatan black pig skin was treated in vitro using a device similar to device 500 of
The treatment parameters are shown in Table D.
The results of the experiment are shown in
Referring to
3. Experiment 3—Treatment of Tissue using 2940 nm and a Pitch of 220 μm
In this experiment, tissue from a Yucatan black pig in vitro was treated with a device similar to device 500 having beam spaced by 220 micrometers, and that irradiated the tissue at a wavelength of 2940 nm. The skin was defrosted prior to testing and warmed to room temperature. The skin was marked with a marking pen and treated with the EMR. The applied energy was verified after every shot of EMR. The glass window of the tip of the applicator was cleaned after each treatment. The energy readings varied by less than 5%.
The skin was then stretched and pinned down on a flat surface. A drop of black tattoo ink was placed on the treated area and massaged into the micro-holes. (In another test, red organic molecules in water (Eosin) were applied to the micro-holes in a method similar to the procedure described for tattoo ink.) The skin was released, and a 6 mm biopsy was obtained from the treated area. The biopsy was frozen and manually cut into 100-300 micron sections. The sections were examined with a BH2 light microscope (Olympus) using a CoolPix-8400 photo camera (Nikon). The skin specimen was treated according to tattoo ink particles trapping method inside of micro channels. The treatment parameters are shown in Table E.
Referring to
Referring to
These experiments demonstrate, among other things, that the micro-holes can be used for incorporation of drugs and/or other substances, into skin or other tissue in vivo. For example, a drug or other substance having a low absorption rate can be placed in a set of micro-holes for incorporation into the body over a period of time, such as one or more months. Such substances could include, for example, birth control drugs, medications, or a nicotine-containing substance for use by persons in the process of quitting smoking. Many other substances are possible.
By way of example, the tattoo ink that was used in the forgoing experiments do not penetrate the tissue and provide a profile of the resulting channel when imaged. On the other hand, the organic ink molecules (Eosin B) do penetrate through the tissue, and no channel profiles were seen. Thus, given that the molecular weight of the Eosin B is more than 600, substances having a molecular weight less than or equal to 600 likely will penetrate tissue. Thus, the channels can be used to deliver drugs and other substances, preferably having an atomic weight of approximately 600 or less. Further, as a general guide, particles having a diameter of approximately 0.05 μm to 100 μm will likely remain in a micro-hole and not diffuse, be absorbed, or otherwise be incorporated into the tissue. Particles having a diameter of less than approximately 0.05 μm, will likely diffuse, be absorbed or otherwise be incorporated into the tissue.
However, one skilled in the art will appreciate that many other factors will affect whether and to what degree a substance will penetrate into tissue. Thus, in other embodiments, substances having a molecular weight greater than 600 may be used. Similarly, some substances having molecular weights less than 600 may not effectively penetrate into the tissue from the micro-holes due to other factors such as the type of tissue, the size of the micro hole, and the chemical structure and nature of the substance. Similarly, particles having a diameter greater than approximately 0.05 μm may diffuse, be absorbed or otherwise be incorporated into the tissue, and particles having a diameter less than approximately 0.05 μm may not diffuse, be absorbed or otherwise be incorporated into the tissue. Thus, many different embodiments are possible.
H. Delivery of Substances For Absorption into Tissue to Increase Optical Clearance of the Tissue.
Micro-holes can also be used as channels to inject a clearing compound, such as, for example, glycerol. Referring to
As shown in
The ability to introduce substance that can then diffuse into the tissue to alter the translucence, transparency, and/or opacity of the tissue has many practical applications. For example, such clearing substances can be used to increase the transparency of the skin to provide increased contrast between the tissue and a chromophore prior to irradiating the chromophore with EMR or other energy. This will decrease the amount of energy absorbed by the tissue surrounding the chromophore, increasing the relative selectivity of the chromophore, decreasing the energy required for, e.g., selective thermolysis, reducing or eliminating the need for cooling, and reducing or eliminating pain. Similarly, increasing the transparency of the tissue allows for improved imaging of structures within the tissue, and may allow imaging of some tissues that would otherwise be too opaque to be viewed.
I. The Use of Micro-Holes to Treat Nail Fungus
In one embodiment, using device 500 as shown in
However, EMR-treated islets can be created to treat diseases of the nails, such as onychomycosis and other infectious diseases at the human nails and their surrounding anatomical sites.
The tissue can be treated directly with EMR. Additionally, photodynamic treatment of the tissue by direct photo activation of endogenous photosensitizers can be used by applying one or more wavelengths of light to the photosensitizer.
Another mechanism for the treatment is to enhance penetration of drugs, other substances or other exogenous photosensitizers through the infected nails. One such mechanism is the use of EMR to create an array of traverse micro-holes in a nail. To create an array of micro-holes, several mechanisms may be used, including, without limitation, single or multiple wavelength light, microwave or ultrasound devices. Dimensions and orientations of the micro-holes could be controlled to suit the application. For example, diameters of holes could be 50-75 micron or greater. Similarly, the micro-holes may be perpendicular to the nail surface or at an angle, depending on the treatment requirement.
The depth of the micro-holes also may be controlled. Depths are dependant on the treatment settings, and the depth can be controlled, for example, by applying one or more pulses of EMR, each successively deepening or enlarging the hole. The treatment method may involve sequential treatment with photosensitizers, chromophores, medicines, or washing techniques in any possible order.
Several exemplary approaches for using micro-holes to treat diseases of the nails have been tested. (Other approaches, which have not been tested, are possible, however.) These approaches are: (1) application of an exogenous chromophore to the micro-holes that is activated with EMR following application; (2) the application of drugs or other substances to the micro-holes that is not activated with EMR following application; and (3) washing the affected tissue from underneath the nail using an antiseptic solution.
1. Application of an Exogenous Chromophore
In this embodiment, a suspension or some other formulation of desirable exogenous chromophores (photosensitizers) are applied to the openings of the micro-holes. The chromophores penetrate the nail through the holes, for example by simple diffusion or by employing other approaches, such as vesicle/particle transporters, by physical, chemical or electrical manipulations (for example, electroporation, iontoporation, sonophoresis, magnetophoresis, photomechanical waves, niosomes, transfersomes etc.).
When the chromophore that is applied reaches the targeted areas (such as areas infected with fungus) different wavelengths of light sources can be used for the photodynamic therapy. The wavelength(s) used for the photodynamic therapy will depend on various factors such as the absorption properties of the active compound. Several applications of the active compound and several treatments with EMR may be required. In some embodiments, different EMR sources and different chromophores (photosensitizers) can be used.
2. Application of Drugs and/or Other Substances
In this embodiment, a drug and/or other substance is applied in a manner that is similar to that of Approach One. However, the drug or other substance that is applied is not photoactivated following application. Micro-holes with desirable properties are created. Drugs and/or other substances, such as a topical cream, solution, suspension etc., are applied to the openings of micro-holes in the surface of the nail. The substances applied penetrate the nail by an appropriate method such as vesicle/particle transportation, or by other physical, chemical or electrical methods. In some cases, natural diffusion of the active ingredients of the medicine through the hole may be the most efficient delivery mechanism. Several applications of the active compound and several treatments with EMR may be required in some treatments. The combination of two or more biologically active ingredients can also be used in appropriate circumstances.
3. Washing of an Infected Area
In this embodiment, parasites are washed out from the affected space under the nail. A washing antiseptic solution can be pumped under the nail through the micro-holes by applying of pressure. In some embodiments, the solution can be extracted by creation of a vacuum. One or more multi-cycle pump in/pump out steps could be used to wash out of parasites from the treated area at the desirable level. The removal of parasites at the desirable level may also be achieved by a mechanical wash or with a mechanical removal of the infected matter, which may be followed by, or accomplished in parallel with, the application of a disinfectant in the treated area.
Wash out and disinfection steps could be accomplished with one solution as a one step treatment or sequentially with two solutions. A one step treatment solution could contain antiseptic compound(s) and compound(s) which will enhance detachment of parasites from the treatment area. The entire affected area could be treated as one target region or it could be divided as an independent segments that are treated at different times or using different regimens. The approach could employ one or more treatment cycles or applications.
4. Exemplary Experiments
Several in vitro and in vivo experiments were performed using a device providing an array of beams at a wavelength of 2940 nm. The device was essentially the same as the embodiment described in conjunction with device 500 of 7-9. For each experiment, direct and indirect evidence of the formation of micro-holes was obtained. Micro-holes were created in wet and dry paper, in vivo humans and ex vivo pig skin and in vivo and in vitro human nails. The creation of holes in vitro was verified by observation of the treated items under a microscope. The creation of holes in vivo was verified by observation and by applying a solution of 10% ammonia on the treated spot (on both skin and nail). The experiments demonstrated that EMR can be employed to successfully ablate tissue and create traverse holes in the tissue, including human nails and skin.
a. Experiment 1—Treatment of Dry Paper
A sheet of paper was treated with EMR at a wavelength of 2940 nm. The treatment parameters were 8-10 mj per beam and a pulse width of 200 microseconds. As is shown in
b. Experiment 2—Treatment of Wet Paper
A sheet of paper was wetted and trapped between two glass slides. The slides were oriented parallel to beam trajectory in the same plane. The distance between the paper and device was 1-3 mm. The paper was irradiated with EMR having a wavelength of 2940 nm, at 18-20 mj per beam and a pulse width of 200 microseconds. As it is shown in
c. Experiment 3—Treatment of Slice of ex vivo Pig Skin
A thin slice of fresh pig skin was trapped between two glass slides and treated similarly to the wet paper described in Experiment 2, using the same treatment parameters. As it is shown in
d. Experiment 4—Traverse Micro-Holes in the Human Nail in vivo.
EMR-treated islets were created generally perpendicular to the surface of a human finger nail. The parameters employed in this experiment were the same as those described in Experiments 2 and 3. However, in this case, the laser was fired twice, while it was fired once in Experiments 2 and 3. As a result of the treatment, the subject had a tingling sensation after the second firing but did not experience pain from the treatment. A burning sensation was felt after applying a 10% ammonia solution, which was very similar to the sensation experienced when ammonia contacts broken skin. Referring to
Referring also to
e. Experiment 5—Traverse Hole in the Human Nail in vitro.
Referring to
The results indicate that EMR at a wavelength of 2940 nm can be used successfully to create micro-holes that extend through human nail tissue and therefore could be used to create channels for the delivery of different pharmaceutical compounds through the human nails.
J. Additional Applications
EMR-treated islets can be used in a variety of applications in a variety of different organs and tissues. For example, EMR treatments can be applied to tissues including, but not limited to, skin, mucosal tissues (e.g., oral mucosa, gastrointestinal mucosa), ophthalmic tissues (e.g., conjunctiva, cornea, retina), and glandular tissues (e.g., lachrymal, prostate glands). As a general matter, the methods can be used to treat conditions including, but not limited to, lesions (e.g., sores, ulcers), acne, rosacea, undesired hair, undesired blood vessels, hyperplastic growths (e.g., tumors, polyps, benign prostatic hyperplasia), hypertrophic growths (e.g., benign prostatic hypertrophy), neovascularization (e.g., tumor-associated angiogenesis), arterial or venous malformations (e.g., hemangiomas, nevus flammeus), and undesired pigmentation (e.g., pigmented birthmarks, tattoos), sebaceous glands, disorders of sebaceous glands, sweat glands (e.g., for permanent reduction of perspiration).
In another embodiment, skin oils, especially on the face, can be reduced by killing or reducing the activity of sebaceous glands. More effective delivery of oil secretion suppressors into skin can also be achieved to control oil levels on the skin surface and reduce oil-induced skin surface brightness (reflectance).
The lattices can be used post-treatment to, for example, facilitate the application and/or absorption of medication to the treated tissue to aid the healing process. Various types of medication can be applied, including topical substances intended to have an immediate effect or capsulated drugs intended to be released slowly. An example of the latter is Vitamin A, which can be applied to be released over and extended period of time (e.g., one month) to further enhance the healing process. Additionally, combinations of medication can be applied. Similarly, antibiotics can be applied to prevent infection, or a film can be applied across the surface of the tissue to prevent infection, such as a polymeric film released or applied across the surface of the tissue following treatment.
While only certain embodiments have been described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope as defined by the appended claims. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described specifically herein. Such equivalents are intended to be encompassed in the scope of the appended claims.
The patent, scientific and medical publications referred to herein establish knowledge that was available to those of ordinary skill in the art. The entire disclosures of the issued U.S. patents, published and pending patent applications, and other references cited herein are hereby incorporated by reference.
All technical and scientific terms used herein, unless otherwise defined below, are intended to have the same meaning as commonly understood by one of ordinary skill in the art. References to techniques employed herein are intended to refer to the techniques as commonly understood in the art, including variations on those techniques or substitutions of equivalent or later-developed techniques which would be apparent to one of skill in the art. In addition, in order to more clearly and concisely describe the claimed subject matter, the following definitions are provided for certain terms which are used in the specification and appended claims.
As used herein, the recitation of a numerical range for a variable is intended to convey that the embodiments may be practiced using any of the values within that range, including the bounds of the range. Thus, for a variable which is inherently discrete, the variable can be equal to any integer value within the numerical range, including the end-points of the range. Similarly, for a variable which is inherently continuous, the variable can be equal to any real value within the numerical range, including the end-points of the range. As an example, and without limitation, a variable which is described as having values between 0 and 2 can take the values 0, 1 or 2 if the variable is inherently discrete, and can take the values 0.0, 0.1, 0.01, 0.001, or any other real values ≧0 and ≦2 if the variable is inherently continuous. Finally, the variable can take multiple values in the range, including any sub-range of values within the cited range.
Or. As used herein, unless specifically indicated otherwise, the word “or” is used in the inclusive sense of “and/or” and not the exclusive sense of “either/or.”
As used herein, EMR includes the range of wavelengths approximately between 200 nm and 10 mm. Optical radiation, i.e., EMR in the spectrum having wavelengths in the range between approximately 200 nm and 100 μm, is preferably employed in some of the embodiments described above, but, also as discussed above, many other wavelengths of energy can be used alone or in combination. Also as discussed, wavelengths in the higher ranges of approximately 2500-3100 nm may be preferable for creating micro-holes using ablative techniques. The term “narrow-band” refers to the electromagnetic radiation spectrum, having a single peak or multiple peaks with FWHM (full width at half maximum) of each peak typically not exceeding 10% of the central wavelength of the respective peak. The actual spectrum may also include broad-band components, either providing additional treatment benefits or having no effect on treatment. Additionally, the term optical (when used in a term other than term “optical radiation” ) applies to the entire EMR spectrum. For example, as used herein, the term “optical path” is a path suitable for EMR radiation other than “optical radiation.”
It should be noted, however, that other energy may be used to for treatment islets in similar fashion. For example, sources such as ultrasound, photo-acoustic and other sources of energy may also be used to form treatment islets. Thus, although the embodiments described herein are described with regard to the use of EMR to form the islets, other forms of energy to form the islets are within the scope of the invention and the claims.
This application claims the benefit of U.S. Provisional Application No. 60/877,826, filed Dec. 29, 2006. This application is a continuation-in-part application of U.S. application Ser. Nos. 11/097,841, 11/098,000, 11/098,036, and 11/098,015, each of which was filed Apr. 1, 2005 and entitled “Methods and products for producing lattices of EMR-treated islets in tissues, and uses therefore” and each of which claims priority to U.S. Provisional Application No. 60/561,052 , filed Apr. 9, 2004, U.S. Provisional Application No. 60/614,382, filed Sep. 29, 2004, U.S. Provisional Application No. 60/641,616, filed Jan. 5, 2005, and U.S. Provisional Application No. 60/620,734, filed Oct. 21, 2004. This application is a continuation-in-part application of U.S. application Ser. No. 11/235,697 that was filed on Sep. 21, 2005 and entitled “Method and Apparatus for EMR Treatment”, which is a continuation of U.S. application Ser. No. 10/033,302 (now U.S. Pat. No. 6,997,923) that was filed on Dec. 27, 2001 and entitled “Method and Apparatus for EMR Treatment”, which claimed priority to U.S. Provisional Application No. 60/258,855 that was filed Dec. 28, 2000. Each of the applications and provisional applications identified above is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60877826 | Dec 2006 | US | |
| 60561052 | Apr 2004 | US | |
| 60614382 | Sep 2004 | US | |
| 60641616 | Jan 2005 | US | |
| 60620734 | Oct 2004 | US | |
| 60561052 | Apr 2004 | US | |
| 60614382 | Sep 2004 | US | |
| 60641616 | Jan 2005 | US | |
| 60620734 | Oct 2004 | US | |
| 60561052 | Apr 2004 | US | |
| 60614382 | Sep 2004 | US | |
| 60641616 | Jan 2005 | US | |
| 60620734 | Oct 2004 | US | |
| 60561052 | Apr 2004 | US | |
| 60614382 | Sep 2004 | US | |
| 60641616 | Jan 2005 | US | |
| 60620734 | Oct 2004 | US | |
| 60258855 | Dec 2000 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10033302 | Dec 2001 | US |
| Child | 11235697 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11097841 | Apr 2005 | US |
| Child | 11966625 | US | |
| Parent | 11098000 | Apr 2005 | US |
| Child | 11097841 | US | |
| Parent | 11098036 | Apr 2005 | US |
| Child | 11098000 | US | |
| Parent | 11098015 | Apr 2005 | US |
| Child | 11098036 | US | |
| Parent | 11235697 | Sep 2005 | US |
| Child | 11098015 | US |
