HK1120714B - Method and apparatus for therapeutic emr treatment of the skin - Google Patents

Description

Method and apparatus for EMR treatment of skin

This application is a divisional application entitled "method and apparatus for EMR treatment of skin" filed 12/27/2001 with application number 200510129098.1.

Technical Field

The present invention relates to methods and apparatus for using electromagnetic radiation (EMR) for a variety of different therapeutic treatments, and more particularly to methods and apparatus for dermatological treatment by using spatially confined concentrated EMR to form a treatment or lesion area substantially surrounded by a residual area.

Prior art of the invention

Various different forms of both coherent and incoherent electromagnetic radiation, in particular optical radiation, have been used for many years for various medical treatments, in particular for dermatological treatments. Such treatments include, but are in no way limited to, removal of unwanted hair, rejuvenation of skin, treatment to eliminate venous lesions, treatment to treat acne, cellulite, pigmented lesions, and psoriasis, treatment to remove tattoos, skin, and other cancers, and the like. Most of these treatments have been implicated in one way or another in the use of a process known as selective radiation pyrolysis [ see, e.g., Anderson RR, Parrish j. in Science 1983; 220: "Selective photo catalysis: precision microsurger by Selective Absorption of the Pulsed Radiation (Selective photothermolysis: precision microsurgery accomplished with Selective Absorption of Pulsed Radiation) involves irradiating a target area with Radiation at a wavelength preferentially absorbed by a chromophore (either a natural chromophore or an artificially introduced chromophore), where heating of the chromophore directly or indirectly affects the desired treatment.

While these techniques are useful for many of the indicated applications, these techniques have a number of significant limitations. First, treatments performed over relatively large areas (e.g., skin rejuvenation and hair removal, especially skin rejuvenation) can cause varying degrees of skin damage over the actual treated area. In particular, such treatments can sometimes result in separation of skin layers. These relatively large areas of skin damage often take weeks or more to heal, and subsequent treatment normally cannot be performed during this time period. It would be preferable if these procedures could be accomplished in a manner that would result in smaller, spaced-apart lesions that heal faster, which would both increase patient comfort and the ability to complete follow-up procedures more quickly. Furthermore, many treatments, such as hair removal and wrinkle removal, require that the treatment be completed in only certain small parts or areas of a much larger treatment area; however, current processing techniques typically require that processing be completed over the entire processing area rather than only certain selected areas of the processing area that require processing.

Another potential problem is the need for chromophores in the target area that selectively absorb the applied radiation to generate the heat required for treatment. First, the region above the treatment region contains chromophores that preferentially absorb or otherwise absorb the applied radiation to such an extent that such chromophores are also heated, and care must be taken in any treatment to ensure that such heating does not cause epidermal or dermal damage. Various forms of cooling (sometimes aggressive cooling) of such laminated areas are often necessary to allow such treatments to be accomplished without damaging the overlying skin. For example, heating of melanin in the epidermis [ particularly at the dermal-epidermal (DE) junction ] is a problem with respect to hair removal or other treatments that target melanin. Where the targeted chromophore is water, substantially all tissue in and above the treatment area will absorb the radiation and will be heated, thereby making controlled treatment of the selected body part difficult and increasing the likelihood of unwanted peripheral damage.

Another problem with selective radiation pyrolysis is that the wavelength selected for radiation is typically dictated by the absorption characteristics of the chromophore being utilized. However, such wavelengths may not be optimal for other purposes. For example, skin is a scattering medium, but such scattering is much more pronounced at certain wavelengths than at others. Unfortunately, wavelengths that are preferentially absorbed, for example by melanin (a frequently used chromophore) are also wavelengths at which substantial scattering occurs. This is also true for the wavelengths typically used to treat venous lesions. Photon absorption in skin also varies across the optical band, and the wavelengths prescribed by selective photothermolysis are often those that are highly absorbed by skin. The fact that the wavelengths typically utilized for selective photothermolysis are highly scattered and highly absorbed limits the ability to selectively target certain parts of the body, particularly the depth at which treatment can be accomplished efficiently and effectively. Furthermore, the fact that the energy applied to the target area is either scattered, does not reach the body part undergoing treatment, or is absorbed in the overlying or surrounding tissue causing unwanted potentially dangerous heating of such tissue results in a very inefficient optical dermatologic treatment. This inefficiency for such treatment means that larger and more powerful EMR sources are required to achieve the desired therapeutic result and additional expense and energy must be utilized in order to mitigate this unwanted heating effect by surface cooling or other suitable techniques. Thermal management for more powerful EMR sources is also a problem, often requiring expensive and bulky water circulation or other thermal management mechanisms. Furthermore, since the concentration of chromophores in a target (e.g., melanin in hair) varies widely from target to target and from patient to patient, it is difficult to determine optimal values, and even appropriate parameters, for effective treatment of a given target using selective photothermolysis. High absorption by certain types of skin, for example, those with raw skin and those with very dark skin, often makes certain treatments difficult or even impossible to safely administer. Therefore, a technique that allows safe treatment of all types and skin complexion (preferably with little or no pain and preferably using substantially the same parameters) is desirable.

Another problem with existing treatments is that the amount of energy that can be applied to the treatment area is often limited by the pain experienced by the patient even where damage to the epidermis, scarring of the skin, or other damage is not an issue. Ideally, EMR dermatology procedures, which are commonly used for cosmetic purposes, should be painless or substantially painless. Although if the procedure is to be performed by a physician, pain can be controlled by the use of local anesthesia or even by forcing the patient to sleep, there is a risk in using any anesthetic, and the use of a needle for the administration of a local anesthetic is undesirable for cosmetic procedures. It is therefore preferable if the patient's pain is substantially likely to be reduced or eliminated without the need for such procedures, while still allowing sufficient radiation to be applied to achieve the desired therapeutic result.

In addition, there are occasions when it is necessary or desirable to perform microsurgery on a patient's skin (particularly near the skin surface); the area to be treated belongs to the field of sizes in the micrometer range, for example 10 micrometers, a size that cannot be treated with a scalpel. Existing EMR devices used to perform microsurgery are also not suitable for performing surgery on such small targets. There is a need for improved techniques for performing such delicate microsurgery.

Furthermore, while EMR techniques are available for treating some of the conditions previously identified, such techniques for treating scars, including acne scars, chicken pox scars, and the like, for tumors in the skin resulting from scar tissue, for tightening the scar, for treating certain parasites, do not currently exist. Therefore, effective techniques for dealing with such situations are needed.

Another problem is that the prior art often causes blisters and other skin problems in eliminating tattoos or pigmented lesions particularly close to the skin surface. It would also be desirable to have an improved technique that would allow such tattoos to be faded in a sufficiently gentle manner and/or ultimately eliminate it without causing damage to the patient's skin or significant patient inconvenience. Similar techniques for treating various skin imperfections are also desirable.

Finally, while techniques are currently available that are relatively effective in treating large venous lesions, such techniques are not as efficient in treating spider veins and other venules. Similar inefficiencies exist where radiation is applied over a relatively large area of the patient's skin and only within a relatively small portion of such area that needs to be treated.

Accordingly, there is a need for improved methods and apparatus for EMR therapeutic treatment, particularly for optical dermatology treatments, which allow for more selective treatment in a target region and which do not rely on selective photothermolysis, such that the wavelengths utilized may be selected for more efficient delivery of radiation at selected depths to desired target volumes, particularly to certain selected portions of such target volumes that are preferably surrounded by portions that are not treated, and that appropriate parameters for treating a given target may be more easily determined.

Summary of the invention

In accordance with the above, the invention provides a method and apparatus for performing a treatment on a volume located at area and depth coordinates of a patient's skin, the method comprising providing a radiation source and applying radiation from the radiation source to an optical system which concentrates the radiation to at least one depth within the depth coordinates of the volume and to a selected area within the area coordinates of the volume, the at least one depth and the selected area defining a three-dimensional spatial treatment portion within an untreated portion of the volume in the volume. The device has a radiation source and an optical system for applying radiation from the radiation source to the device, the optical system concentrating the radiation to at least one depth in the volume and to selected regions in the volume, the at least one depth and region defining a three-dimensional spatial treatment portion in the volume within an untreated portion of the volume. For both the method and the apparatus described, the ratio of treated portion to volume may be between 0.1% and 90%, however, preferably between 10% and 50%, more preferably between 10% and 30%. In each case, the treated portion can be a cylinder, sphere, ellipsoid, solid cuboid, or plane of at least one selected size and thickness. The processing sections may also be isolated rows of selected length and thickness. The optical system may apply radiation to all of the treatment portions substantially simultaneously, or the optical system may apply radiation to at least selected treatment portions sequentially.

The patient's skin on the at least one treatment portion may also be pre-cooled to a selected temperature for a selected duration, the selected temperature and duration for pre-cooling preferably being sufficient to cool the skin to at least a selected temperature below normal body temperature at least at the at least one depth for the treatment portion. For selected embodiments, the skin is cooled to at least the selected temperature and to a depth below the at least one depth for the treatment portions such that the at least one treatment portion is substantially surrounded by cooled skin. Cooling may continue during the application of radiation, and for this embodiment, the duration of the application of radiation may be greater than the thermal relaxation time of the treatment portion. The wavelength for the radiation source is preferably chosen such that there is neither strong absorption nor strong scattering in the patient's skin above the volume to be treated. For deeper depth coordinates, the optical system is focused to a selected depth below at least one depth of the treatment portion in order to achieve concentration at a desired depth coordinate in the patient's skin. Selected conditions in the volume where treatment is to be completed and/or the patient's skin above this volume may be detected, the results of which are used to control the portion of the treatment to which radiation is concentrated during application of the radiation.

The applied radiation preferably has an output wavelength that is at least partially a function of at least one depth of the treatment portion. More specifically, the wavelength of the applied radiation may be selected as a function of the applied radiation: the depth is between.05 and.2 mm, the wavelength is 400-; 2 to 3 mm, wavelength 500-; 3 to 5 mm, wavelength 600 + 1380nm and 1520 + 1850nm and 2150 + 2260nm, wherein 900 + 1300nm and 1550 + 1820nm and 2150 + 2250nm are preferred; 5 to 1.0 mm, 600-1370nm and 1600-1820nm, wherein 900-1250nm and 1650-1750nm are preferred; the depth is 1.0 rather than 2.0 mm, the wavelength is 670-1350nm and 1650-1780nm, wherein 900-1230nm is preferred; a depth of 2.0 to 5.0 mm, a wavelength of 800-.

The methods and apparatus described may also be utilized for treating a variety of different medical conditions. In the case of treatment of a venous lesion at a selected depth, the treatment parameters, including the optical system and the wavelength of the applied radiation, are selected such that at least one depth of the treated portion approximates the depth of the vessel being treated. Likewise, in the case where the treatment is skin readjustment by treatment of collagen or hair removal, the treatment parameters including the optical system and the radiation wavelength are selected such that the at least one depth is the depth of collagen between the dermis and at least one of the bulge and matrix as a hair follicle, respectively. The teachings of this invention can also be used to treat acne, target and destroy lipomas, treat cellulite, remove tattoos, treat pigmented lesions, treat downward and other scars and other skin imperfections, and treat various other conditions in the skin.

The optical system utilized in practicing this invention may include an array of optical elements to which radiation from a radiation source is to be applied at least simultaneously to a plurality of optical elements, each of which concentrates radiation to a selected portion of the volume. For example, each optical element may be focused or concentrated onto a row of selected length and thickness, with rows for some elements at selected angles to rows of other elements. Alternatively, the optical system may include means for scanning the radiation applied to the optical concentrating component so as to focus the radiation onto N processing portions in succession, where N ≧ 1. The optical system may instead include a depth-adjustable optical focusing element and a positioning mechanism for such an optical focusing element that moves the element over successive treatment portions for focusing. The apparatus may further include means for cooling at least the portion of the patient's skin at the selected area coordinates to a selected temperature, and control means for selectively operating the cooling means to pre-cool the portion of the patient's skin for a selected duration before and/or during the application of radiation. The cooling mechanism and control device may pre-cool the skin to a temperature and for a time sufficient to cool at least that portion of the skin to a selected temperature below normal body temperature and to at least one depth of the treatment portion, or may cool to a depth below at least one depth of the treatment portion, in which case the treatment portion is substantially surrounded by cooled skin. The apparatus may further comprise a detector for at least one selected condition in the volume and/or in a portion of the patient's skin above the volume, the optical system being operable in response to the detector for controlling the treatment portion of the volume receiving the concentrated radiation.

The present invention also includes a method and apparatus for performing a treatment on a volume located in area and depth coordinates of the patient's skin, including providing a radiation source and pre-cooling the patient's skin in coordinates over at least a portion of the area of the volume to a selected temperature for a selected duration of time, the selected temperature and duration being sufficient to cool the skin to a depth below the depth coordinate of the volume; and applying radiation to an optical system that concentrates the radiation to at least one depth coordinate and a selected area within the area coordinates to define treated portions in the volume, the treated portions being less than the total volume, and each treated portion being within an untreated portion and substantially surrounded by cooled skin. More specifically, a mechanism may be provided for cooling the patient's skin at the area coordinates to a selected temperature, and control means may be provided for selectively operating the cooling mechanism to pre-cool the skin for a selected duration before and/or during application of radiation, the mechanism and control means cooling to a temperature for a duration sufficient to cool the skin to at least a selected temperature below normal body temperature to a depth at least below the depth coordinates of the volume. Cooling the patient's skin with the cooling mechanism may continue during the step of applying radiation, and the duration of applying radiation may be greater than the thermal relaxation time of each treatment portion.

Finally, the present invention includes a method and apparatus for performing a therapeutic treatment on a patient's skin by concentrating selected at least one wavelength of applied radiation onto a plurality of selected three-dimensionally located treatment portions, wherein the treatment portions are within non-treatment portions.

The above and other objects, features and advantages of the present invention will become apparent from the following more particular description of various embodiments of the invention, as illustrated in the accompanying drawings in which like or related reference numerals are used for common elements in the various figures.

Brief description of the drawings

Fig. 1-1B is a top view of three optical systems including an array of optical elements adapted for use in delivering radiation in parallel to a plurality of target portions.

Fig. 2-3C are side views of various lens arrays suitable for use in delivering radiation in parallel to a plurality of target portions.

Fig. 4-4C are side views of fresnel lens arrays suitable for use in delivering radiation in parallel to a plurality of target portions.

Fig. 5-5B are side views of a holographic lens array suitable for use in delivering radiation in parallel to a plurality of target portions.

Fig. 6-6A are side views of gradient lens arrays suitable for use in delivering radiation in parallel to a plurality of target portions.

Fig. 7-7B are top views of various matrix arrays of cylindrical lenses, some of which are adapted to provide line focusing for a plurality of target portions.

Fig. 8-8C are cross-sectional or side views of one layer of a cylindrical lens matrix system suitable for delivering radiation in parallel to a plurality of target portions.

Fig. 9-9B are perspective and cross-sectional side views, respectively, of a two-layer cylindrical lens array suitable for delivering radiation in parallel to a plurality of target portions.

Fig. 10-13 are side views of various optical objective arrays suitable for use in concentrating radiation to one or more target portions.

Fig. 14-19 are side views of various deflector systems suitable for use with the arrays of fig. 10-13 for movement to successive target portions.

Fig. 20 and 21 are side views of two different zoom optical systems suitable for use in practicing the teachings of the present invention.

FIGS. 22A and 22B are semi-schematic perspective and side views, respectively, of a section of a patient's skin and apparatus positioned thereon for practicing the teachings of the present invention.

Fig. 23A is a list of preferred parameter ranges for different lesion depths.

Fig. 23B is a list of preferred parameter ranges for short pulses at different lesion depths.

Fig. 23C is a list of preferred parameter ranges for long pulses at different lesion depths.

Detailed description of the invention

Referring first to fig. 22A and 22B, a portion of a patient's skin 200 is shown, the portion including an epidermis 202 overlying a dermis 204, the junction of the epidermis and the dermis being referred to as the dermal-epidermal (DE) junction 206. In addition, a treatment volume V is shown at a depth d and with an area a in the skin of the patient. The treatment volume V may contain one or more venous lesions to be destroyed or removed; may comprise a plurality of hair follicles that are to be permanently damaged, or at least to be damaged, thereby causing temporary hair loss, or to be stimulated to cause hair growth; collagen reconstituted in various ways (e.g., by temporary disruption to stimulate regrowth, particularly for skin rejuvenation and wrinkle removal) can be included in the area under the DE junction; may contain melanoma to be removed, venous lesions, pigmented lesions, port wine stains, psoriasis, scars, or other skin blemishes or tattoos to be removed, or some other body component on which to perform a photomedical procedure.

Additionally, a system 208 for delivering optical radiation to the volume V is also shown. The system 208 includes an EMR radiation source 210, which may be a coherent light source, such as a solid state laser, dye laser, diode laser, fiber laser, or other coherent light source, or may be an incoherent light source, such as a flash lamp, halogen lamp, bulb, or other incoherent light source used to deliver optical radiation in dermatology procedures. Sources of acoustic, radio frequency or other EMF (electromagnetic frequency) radiation may also be used in suitable applications. The output from the radiation source 210 is applied to an optical system 212, preferably in a state where the output head is in contact with the skin surface of the patient, as shown in fig. 22B. Where an acoustic, radio frequency or other non-optical EMR source is used as the source 210, the system 212 will be a system suitable for concentrating or focusing such EMR, for example, a phased array, and the term "optical system" should be interpreted as appropriate to include such a system.

Various embodiments of optical system 212 are discussed below and shown in various figures. In general, the function of the system 212 is to receive radiation from the radiation source 210 and focus/concentrate such radiation into one or more focused beams 222 directed at a selected one or more treatment or target portions 214 in the volume V, the focusing being both depth d and spatial in region a. Thus, the applied EMR energy is concentrated to deliver more energy to the target portion 214. Depending on system parameters, portion 214 may be a cylinder, sphere, or ellipsoid of a selected diameter and thickness, and may have a square or rectangular cross-section for one embodiment. The portions of each shape may extend through the volume V or may be formed in a single layer and staggered layers thereof. The target portion 214 may also be (a) an elongated strip that may extend through the volume V, or be formed in a single thin layer in the volume V, or be formed in a staggered layer in the volume; or (b) may be one or more thin layers formed in the volume V. As will be discussed in more detail later, the optical system 212 may focus all or a selected subset of the portions 214 simultaneously, may include some type of optical or mechanical optical scanner for moving the radiation focused to depth d onto successive portions 214, or may produce an output that is focused to depth d and naturally moves the radiation to the desired successive portions 214 over the skin surface over the volume V, either manually or with a two-dimensional or three-dimensional (including depth) positioning mechanism. For the latter two embodiments, the movement may be directly from one part to the other for focusing thereon, or the movement may be in a standard pattern (e.g., a grid pattern) with the EMR source being fired only when located over the desired part 214.

To cool the surface of the skin 200 over the treatment volume V, a cooling element 215 is also included. As shown in fig. 22A and 22B, cooling element 215 acts on optical system 212 to cool the portion of this system that is in contact with the patient's skin and, therefore, the portion of the patient's skin that is in contact with such element. For example, cooling element 215 may be a thermoelectric element, or may be a system for transporting water (preferably chilled water), gas (preferably chilled gas, and possibly even cryogenic gas) over such a portion of the optical system. Other techniques known in the art for cooling the surface of a patient's skin may also be used. Further, where the optical system 212 is not in contact with the patient's skin, cryogenic spray cooling, air flow, or other non-contact cooling techniques may be utilized. A cooling gel on the skin surface may also be used to supplement or replace one of the previously indicated cooling techniques.

The system 208 also includes an optional detector 216, which may be, for example, a CCD camera or other suitable detector for a selected characteristic of the patient's skin. The output from the detector 216 is applied to a control means 218, which is typically a suitably programmed microprocessor, but may also be dedicated hardware or a mixture of hardware and software. The control device 218 controls the turning on and off of the radiation source 210 and may control the power profile of the radiation. Control means 218 is also applied to optical system 212, for example, to control the depth of focus of the optical system and to control the portion or portions 214 onto which radiation is being focused/concentrated at any given moment, for example, by controlling the scanning of the optical system and/or the beam radiated therefrom. Finally, the control means 218 is applied to the cooling element 215 in order to control the skin temperature and the duration of the cooling over the volume V throughout the pre-cooling process and during the irradiation.

System 208 controls various parameters of the applied radiation in accordance with the teachings of the present invention. The data in tables 1-3 were found from Monte-Carlo models of photon propagation using standard parameters of skin scattering and absorption at different wavelengths. These parameters include, but are in no way limited to:

1. the shape of the processing portion 214. Each of these portions may be a thin disc as shown, may be an elongated cylinder, for example, it may extend from a first depth relatively close to DE junction 206 to a second, relatively deep depth, or may be line focused, each line having a selected length, width and orientation, and adjacent lines being spaced by a selected amount, as will be discussed later in connection with the various optical systems to be described. The orientation of the rows for portion 214 need not all be the same in a given application, for example, some of the rows may be at right angles to other rows (see, e.g., fig. 7A and 7B). For greater efficiency, the rows may be oriented around the processing target. For example, the rows may be perpendicular to the vessels or parallel to the wrinkles. Portion 214 may also be spherical, ellipsoidal, and may be, at least for one embodiment, a solid square or rectangle of selected thickness. The shape of the portion 214 is dictated by the combined parameters of the focused optical signal applied to it and the duration of the application, and to a lesser extent the wavelength of the signal is an important factor in determining the shape of the target portion. For example, it has been found that a generally cylindrical portion 214 is obtained with a 1720nm laser operating at about 0.5 joules to 2 joules and having a pulse duration of 0.5 to 2 milliseconds. In contrast, a target portion having a spherical shape is generally obtained using a 1250nm laser operating in the same energy range and having a pulse duration of 0.5 to 3 seconds (average 1 second). The parameters used to obtain a particular partial shape may be determined in a variety of different ways, including empirically. By appropriate control of wavelength, focus, spot size at the surface, and other parameters, the portions 214 may extend through the volume V regardless of shape, may be formed as a single thin layer of the volume V, or may be staggered such that, for example, adjacent portions 214 are in different thin layers of the volume V. The pattern of the target portion in the volume V may also vary with the application. Furthermore, target portion 214 may also be (a) relatively narrow strips formed in a single lamina or interleaved in different laminae (e.g., adjacent strips in different laminae) that may extend across volume V; or (b) may be one or more thin layers formed in the volume V. While all of the existing configurations for target portion 214 may be formed continuously or in parallel, the final configuration with multiple thin layers in volume V may need to be formed continuously. The geometry of the treatment portion 214 controls thermal damage in the treatment portion. Since a sphere provides the greatest gradient and therefore the greatest spatial limitation, it provides the greatest localized biological damage and therefore may be the preferred target shape for applications where this is desired.

2. The size of the processing portion 214. For a depth of about 1 millimeter into the patient's skin, the minimum diameter of the portion 214, or the minimum width of the row 214, is estimated to be about 100 microns; however, much larger sections (a few millimeters or more) are possible. For greater depths, the minimum dimension will be greater.

3. The center-to-center spacing between the sections 214. The center-to-center spacing is determined by a number of factors, including the size of the portion 214 and the processing to be performed. In general, it is desirable that the spacing between adjacent portions 214 be sufficient to protect the patient's skin and aid in the healing of the lesion, while still allowing the desired therapeutic effect to be achieved. In one application, a volume V as small as 4% is damaged (i.e., 4% fill factor); however, the lesion 214 will typically cover substantially more of the treatment volume V. Although theoretically the combined volume to volume V ratio (sometimes also referred to as fill factor) of the treatment portion 214 may be 0.1% to 90%, the preferred range for fill factor is 10% to 50% for some applications and 10% to 30% for most applications. It is important that there be at least some reserved area(s) around each island or treatment/damage area 214 and that this reserved area is sufficient to allow skin rejuvenation that is facilitated by melanosome migration.

4. For the depth d of the volume V. Although small focal spots 214 are difficult to achieve in scattering media such as skin at depths below 1 mm, focusing at depths up to 4 mm and perhaps even deeper may be possible as long as tight focusing is not required and a larger part size 214 (perhaps a few mm) is acceptable.

5. The depth of focus. Although, as can be seen from table 1, the depth d for the volume V and the focal point depth of the optical system 212 are substantially the same when focusing to shallow depths, focusing at greater depths (and sometimes much greater depths) is often necessary in scattering media such as skin to achieve focusing at deeper depths d. The reason for this is that scattering prevents a tight focus from being achieved and results in a minimum spot size and therefore maximum concentration of energy, since the focused beam is substantially above the depth of focus of the beam. The depth of focus may be selected according to known skin characteristics in order to achieve a minimum spot size at a desired depth d.

6. Wavelength. Both scattering and absorption are wavelength dependent. So, although a relatively wide band of wavelengths can still be utilized while achieving a focused beam in the case of shallow depths, the deeper the depth of focus, the more scattering and absorption become a factor, and the narrower the band of wavelengths available to achieve reasonable focusing. Table 1 indicates preferred bands for various depths, although acceptable but less than optimal results are possible outside of these bands.

7. The pulse width. The pulse width of the applied radiation should normally be less than the Thermal Relaxation Time (TRT) of each target portion 214, since longer durations will cause heat to migrate outside the boundaries of these portions. Because portion 214 will typically be relatively small, the pulse duration will also be relatively short as shown in Table 1. However, as the depth increases, and thus the spot size, the maximum pulse width or duration also increases. Again, the values given in Table 1 are the maximum values for a given spot size and are comparedShort pulses may be used. In general, thermal diffusion theory states that for spherical islets the pulse width τ should be τ < 500D²/24, and for a cylindrical island of diameter D should be τ < 50D²/16. Further, if the density of the target is not too high, the pulse width may sometimes be longer than the thermal relaxation time of the target portion 214, such that the combined heat from the target is well below the damage threshold at any point outside of these regions with respect to the tissue at such point. In addition, as will be discussed later, with an appropriate cooling regime, the above-described limitations may not apply, and pulse durations in excess of the thermal relaxation time (and sometimes well in excess of TRT) for the damaged portion 214 may be utilized.

8. And (4) power. The necessary power from the radiation source depends on the desired therapeutic effect, increasing with increasing depth, cooling and decreasing absorption due to wavelength. The power also decreases as the pulse width gradually increases.

9. And (6) cooling. The cooler 215 is typically activated before the radiation source 210 in order to pre-cool the patient's skin to a temperature below normal skin temperature (e.g. 0 to 10 ℃) and to a depth at least at the DE junction 206, and preferably to a depth d of the entire skin area 220 above the protected volume V. However, if the pre-cooling time period is extended to a depth sufficient to cool the patient's skin below the volume V, and particularly if cooling continues after the application of radiation is initiated, then heating will only occur in the illuminated portions 214, each of which will be surrounded by cooled skin, in accordance with the teachings of this invention. Therefore, even if the duration of the applied radiation exceeds TRT for portions 214, heat from these portions will be suppressed and thus thermal damage will not occur outside of these portions. Furthermore, although nerves may be stimulated in the portion 214, cooling these nerves outside the portion 214 will block pain signals from being transmitted to the brain in addition to allowing tight control of the volume of injury, thus allowing the treatment to function with greater patient comfort, and in particular allowing the radiation dose to be applied to affect the intended treatment which may not otherwise be possible because of the resulting pain experienced by the patient. This cooling regime is an important feature of this invention.

10. The numerical aperture. The numerical aperture is a function of the angle theta for the focused radiation beam 222 from the optical device 212. It is preferred that this number (and thus the angle theta) be as large as possible so that the energy of the radiation concentrated in the portion 214 in the volume V is much greater than the energy at other points in the volume V (and in the region 220), thereby minimizing damage to the tissue in the region 220 and in portions of the volume V other than the portion 214 while still achieving the desired therapeutic effect in the portion 214 of the volume V. A higher beam numerical aperture will increase the safety of the epidermis, but it is limited by the scattering and absorption of higher stray reflected light. As can be seen from table 1, the numerical aperture may gradually decrease as the depth of focus increases.

Thus, by judicious selection of the various parameters noted above and others, one or more focused beams of radiation 222 can be implemented to form islands of treatment/damage 214 in the patient's skin in the treatment volume V at a selected depth d. Preferred ranges of parameters for achieving these objectives at various depths are provided in table 1. Tables 2 and 3 illustrate the parameter ranges for short pulses (i.e., less than 10 msec for shallow skin small targets and less than 100 msec for deeper depths) and long pulses, respectively, at various depths. The values in table 2 assume that the above-described deep cooling through volume V has not yet been provided, so that the pulse duration is limited by the thermal relaxation time of the damaged portion 214. Thus, at shorter depths where smaller spots or focal regions (e.g., 50 micron diameter spots) can be achieved, pulse widths of less than 10 milliseconds are necessary, as assumed in table 2, and other parameters are selected accordingly. Conversely, for deeper depths, tight focusing due to scattering cannot be achieved, resulting in relatively large diameter lesion parts 214 and long thermal relaxation times for these parts, and therefore, can provide substantially longer pulse widths, allowing the energy necessary to achieve a therapeutic effect to be provided over longer time intervals. This helps to remove heat from the region 220, and in particular from the skin portion 202 and the DE bond 206 thereof. It also allows the use of a radiation source 210 with a relatively low peak power. From tables 2 and 3, it is also noted that the depth of focus is indicated to be greater than the depth d of the lesion 214. The reason for this has been discussed above.

Another option, when the control means 218 can be preprogrammed for focusing on a selected portion 214 of the target volume V, is to use feedback to control the portion 214 of the volume V on which it is focused, either mechanically by using the detector 216 or by the operator, usually optically, but possibly using other senses of the operator, such as tactile or audible. For example, assuming that the detector 216 is a CCD imaging device, the location of hair follicles, vein lesions, or other target portions in the volume V can be located, and the focused beam 222 is directed specifically to the location of such components. Thus, assuming a hair removal process is performed, detector 216 may locate each hair follicle at the surface above volume V and then focus beam 222 onto each such hair follicle at a selected depth (e.g., 1 mm depth where stem cells are located). The beam may also be focused to a depth extending along the follicle, for example, 0.7-3 mm, to ensure that all elements within the follicle essential to permanently or substantially permanently clear the hair, e.g., destruction of follicle stem cells, are destroyed without substantially damaging dermal tissue surrounding the follicle or damaging the follicle matrix. This result is most easily achieved if the cooling technique discussed above is utilized, wherein the cooling extends below the treatment volume V such that each hair follicle to be treated is surrounded by cooled dermal tissue.

Feedback may also be used to track the vessel or other venous structure to be treated or to track one or more wrinkles to be treated by collagen remodeling. In addition, while the focused beam 222 can be automatically positioned by the control 218 in response to output from the detector 216, such feedback can also be achieved by an operator manually adjusting the position of the optical system 212 to track and treat hair follicles, vein structures, wrinkles, and the like.

More specifically, the scanner used may include three low power laser diodes, preferably of different colors, for detection and one high power laser diode for processing. For example, a scanner may be used to detect the location of a blood vessel and detect the depth of interest. One of the three diodes used for sensing may be a high power diode that can operate in both a sensing mode and a processing mode, and in some cases sensing may be accomplished by only one or two diodes, which may also be used for processing in some cases. A suitable scanner can be used to move the detector and/or processing diodes over the selected pattern. However, although galvanic scanners have been used in the past, contact scanners have been essential for this application because the required focusing of the beam requires contact with something that is not possible with galvanic scanners. Further, the scanner can be programmed to track a particular pattern to find a target, and can be programmed to follow a target once found (e.g., a vein), or the scanning can be manually controlled. Where the scan follows a selected target (e.g., a blood vessel), the illumination may occur at selected points along the blood vessel. It is often necessary to coagulate blood vessels at a selected point or points along the vessel in order to stop blood flow therein and kill the vessel. It should not be necessary to irradiate the entire vessel in order to destroy it.

Where a scanner is used, the area being scanned can be projected onto a screen, thereby providing an effective zoom that facilitates selection of a desired target point in a programmed scan or scan along a target (e.g., a blood vessel). Multiple detectors, which may be filtered to provide different colors, can be used to detect the depth of an object (e.g., a blood vessel) so that the light can be focused at a depth suitable for treatment. Thus, the scan may be three-dimensional. Since the depth is controlled to some extent by the wavelength, the output wavelength is programmable within a limited range and can be used to control the fiber laser for both detecting and treating skin depth. In each case, the treatment may be effected solely by the radiation focused at the selected point, the water normally heated at that point, or the effect of such focusing plus the desired selective absorption of the target at the wavelength used. The chromophore (although usually water) may also be blood or melanin. Furthermore, when treating blood vessels, the vessels can be compressed during treatment, for example, by applying pressure to the vessels, since hemoglobin is not required as a chromophore. This may allow for denaturation and contraction of the vessel wall which can result in a more permanent closure of the vessel and the possibility of permanently closing larger vessels. The location and size of the treatment/lesion islets can be adjusted for different sizes, types and locations of vessels. Likewise, to remove hair, there is no requirement for high melanin content in the hair shaft or follicle, since melanin does not need to be targeted, thereby facilitating easier handling of gray and blond hair.

For port wine stains, the wavelength may be in the range of 0.9 to 1.85 microns for water absorption or in the range of 0.38 to 1.1 microns for hemoglobin absorption, with a fill factor of 10% to 80%, preferably 30% to 50%. The light source may be an arc lamp with filtering and shielding.

The teachings of this invention are also particularly suited for skin rejuvenation treatment by collagen regeneration. In such treatments, since collagen itself is not a chromophore, chromophores (e.g., water) in the tissue or blood in and below the papillary dermis typically absorb radiation and are heated, thereby heating the adjacent collagen, causing selective damage or destruction resulting in collagen regeneration. Release triggering the new perturbation of the blood vessel in this region can also result in the release of fibroblasts that cause the production of new collagen. Although such treatment may be performed only along the line of wrinkles or other blemishes to be treated, such treatment is typically performed over a relatively large area subject to treatment. In accordance with the teachings of this invention, such treatment can be accomplished more efficiently by heating the selected portions 214 with a fill factor of perhaps 30% to 50%, resulting in significant collagen regeneration with less damage and pain to the patient. Such a procedure may be performed over a relatively large area a, or using techniques similar to those discussed above for blood vessels, by periodically firing a beam while over a wrinkle, the beam being traced in a predetermined pattern and fired only at selected points over the wrinkle, or being moved and fired periodically while over it in order to trace the wrinkle. In addition, as for other treatments employing the teachings of this invention, healing occurs relatively quickly, so that subsequent treatments are completed to the extent necessary, perhaps within weeks of the initial treatment, and indeed no more than a month.

Generally, a slight swelling in the skin occurs when collagen is heated, and the slight swelling is caused by contraction of collagen. Thus, this technique can be used not only to remove wrinkles but also to remove other skin imperfections (e.g., acne or chicken pox scars or other scars in the skin), but also to treat cellulite. Although the slight swelling may subside after about one month, the heating also increases the thickness/length ratio of collagen in this area, thus increasing the thickness of collagen, resulting in most improvements from fairly permanent skin rejuvenation/blemish removal.

Other skin imperfections that can be treated with the teachings of this invention include stretch marks other than wrinkles, because these marks are essentially flush with the surface, so collagen shrinkage and regeneration reduces these marks as a result of heating. Down scarring, an elevated scar that occurs after surgery or some trauma, can also be treated in much the same way as port wine stains are treated previously by reducing blood flow to the scar vessels.

In addition to hair removal, treatment of venous lesions, and skin resurfacing, the teachings of this invention can also be used to target and destroy one or more sebaceous glands, for example, to treat acne, to target and destroy excess subcutaneous fat, to treat cellulite, and to provide skin resurfacing in areas where such treatments are not currently practiced (e.g., neck and hands where lesions caused by standard skin resurfacing techniques do not normally heal). Treating only the islets in such areas should leave sufficient undamaged skin structure for healing to occur. The teachings of this invention, as previously indicated, can also be used to remove tattoos, treat scars, treat pigmented lesions, treat downward and other scars, stretch marks, acne and chicken pox scars and other skin blemishes, and treat various other conditions that may exist in a patient's body at a depth of less than about 4 millimeters, such as various skin cancers and possibly PFB. For skin tumors, a combination of a feedback system to localize the tumor location and a remote control system to ensure complete thermal destruction of the tumor may be used. Psoriasis can be treated with substantially the same parameters and in substantially the same manner as used for port wine stains. These teachings can also be used to treat intradermal parasites, such as larval migrant animals, that can be found and selectively killed using the teachings of the present invention.

There are generally three methods of using the present invention for tattoo removal. The first is by using one or more wavelengths absorbed by the tattooing ink, preferably with short pulses of high integral flux, to disrupt or destroy the ink in and between cells. The second technique involves destroying the cells containing the ink, targeting the ink or water in the cells, and causing the release and removal of the ink with the body's lymphatic system. Long pulses in the millisecond to second range with low power and high energy will typically be utilized here. In a third technique, an ablation laser is used to drill 1 to 2 mm spots into the tattoo, thereby ablating or vaporizing both the cells and the tattoo ink in these areas. With a small fill factor, for example in the range of 10% to 80%, preferably in the range of 10% to 30%, such small lesion spots heal well, allowing the tattoo to be progressively illuminated and eventually removed for each of the three treatments. A randomized pattern for each treatment is also preferred for disturbing the clearance pattern.

A particular problem that the teachings of this invention are particularly well suited to address is the treatment of birthmarks or other pigmented lesions in the epidermis. Such lesions are often difficult to treat without blistering using conventional treatment methods. By using lesion islands with a fill factor of 1% to 50% (preferably 10% to 30%) and spot sizes of 100 microns to 1/2 mm, it is possible to treat such lesions without scarring. Since the processing in this case is so close to the surface, focusing is not necessary. Similar treatments with similar fill factors can be used to treat port wine stains or tattoos, but in either of these cases, focusing is necessary because the treatment is at a greater depth. In all cases, the first treatment may result in irradiating only the treated area. Once the treated portion has healed (which typically occurs within a few weeks to a month in the case of lesion-treating islands), one or more additional treatments can be completed to further illuminate the treated area until the lesion, port wine stain, tattoo, etc., are removed. In each case, dead cells containing melanosomes, ink or the like resulting from the treatment will normally be cleared by the body via the lymphatic system.

Thus, there have been provided (a) devices that allow a variety of different therapeutic treatments to be performed on a patient's body at depths up to about 4 mm; (b) allowing only islands of damage in three dimensions to occur, thereby promoting healing (by allowing blood flow and cell proliferation to continue between the cortex and the islands of damage 214) and reducing patient discomfort; (c) allowing no damage to surrounding parts of the patient's body to be targeted to specific components for treatment, thereby more efficiently using the applied radiation while reducing peripheral damage to the patient's body due to such treatment; (d) allowing treatment of various types of skin using substantially the same parameters for a given treatment, thereby making the treatment configuration and treatment safe, and (e) allowing the wavelength used for treatment to be the optimal wavelength selected for the depth of treatment, rather than a wavelength defined as optimal for absorption by the targeted chromophore. In fact, although the wavelengths selected for the teachings of this invention normally have significant water absorption, one of the criteria in selecting wavelengths is that they are not even absorbed by water to a significant extent, especially for deeper depths, so that the radiant energy reaches the intended depth without losing a significant amount of energy/photons due to absorption. Concentration of photons/energy in the targeted portion 214 will increase the energy in these portions more than enough to compensate for the reduced absorption at the wavelengths used. Thus, this invention provides a completely new and novel technique for implementing such a process.

Fig. 1-21 illustrate various optical components suitable for use in optical system 212. In these figures, FIGS. 1-9B illustrate various different systems for delivering radiation in parallel to a plurality of target portions 214. The arrays of these figures are typically fixed focus arrays for a particular depth d. This depth can be varied by using arrays with different depths of focus, by selectively varying the position of the arrays relative to the patient's skin surface or target volume V, or by controlling the wavelength of the radiation. Fig. 10-13 illustrate various optical objective arrays that may be used in conjunction with the scanning or deflection systems shown in fig. 14-19 in order to move to one or more successive focusing elements 214 within the target volume V. Finally, fig. 20 and 21 show two different zoom optical systems, which can be moved over the skin of the patient, for example, mechanically or by manual operation, in order to illuminate successive portions 214 thereon.

Referring in more detail to the drawings, FIGS. 1, 1A and 1B show focusing elements 1 on a substrate 3 having boundaries in a hexagonal pattern (FIG. 1), a square pattern (FIG. 1A) and a circular or elliptical pattern (FIG. 1B). Standard optical materials can be used for these elements. Although the hexagonal and square patterns of fig. 1 and 1A can completely fill the working area of the focusing element plate 4, this is not true for the element pattern of fig. 1B. The radiation from the radiation source 210 will typically be applied to all focusing elements 1 simultaneously; however, by using a suitable scanning mechanism, the radiation can also impinge on the elements in sequence, or possibly be scanned in one direction, e.g. illuminating/illuminating four elements simultaneously.

Fig. 2 and 2A are cross-sectional views of a microlens system fused in a refractive material 8 (e.g., porous glass). The refractive index of the material used for the lens 5 must be greater than the refractive index of the refractive material 8. In fig. 2, the beam 11 initially passes through the planar surface 10 of the refractive material 8 and is then refracted by both the major surface 6 and the minor surface 7 of each microlens 5, resulting in a focal point 12 to which the beam is focused. In fig. 2A, the process is reversed, but the result is the same.

In fig. 2B and 2C, the incident beam 11 is refracted by the main lens surface 6 made of the refractive material 8. The surfaces 6 and 7 for the various arrays are either spherical or aspherical.

In fig. 3 and 3A, the lens block 15 is mounted in the base body and in an impregnating material 16. The refractive index of the lens block 15 is greater than the refractive index of the immersion material 16. The impregnating material 16 may be in a gas (air), liquid (water, refrigerant spray) or suitable solid. Gases and liquids can be used to cool the skin. The impregnating substance is typically on the major and minor planar surfaces 13 and 14, respectively. In fig. 3A, the major surface 6 and minor surface 7 degrees of each lens block 15 allow for higher quality focusing. With respect to fig. 3B and 3C, the lens block 15 is fixed on the surface of the refractive material 8, and with respect to a given lens 15, the embodiment of fig. 3C provides a deeper focal point than the embodiment of fig. 3B or any other array shown in fig. 3-3C. The lens arrays shown in fig. 3A-3C are preferred lens arrays in practicing the teachings of this invention.

Fig. 4-4C show fresnel lens surfaces 17 and 18 formed on the refractive material 8. The profile of the fresnel lens surfaces 17 and 18 is varied, the relationship between the radius of the ring 18 and the centre 17 of the fresnel surface making it possible to achieve the required quality of focus. The arrays of fig. 4B and 4C allow higher quality focusing and are other preferred arrays. Surfaces 17 and 18 are either spherical or aspherical.

In fig. 5 and 5A, focusing of the incident beam 11 is achieved by forming a holographic lens 19 (i.e. a photographic hologram) on the surface of the refractive material 8. The holographic lens 19 may be formed on either surface or on both surfaces of the refractive material 8 as shown in fig. 5 and 5A. Fig. 5B shows a holographic material 20 replacing the refractive material 8 of fig. 5 and 5A. The holographic lens is formed in a volume of material 20.

In fig. 6 and 6A, the focusing element is formed by a gradient lens 22 having a major planar surface 23 and a minor planar surface 24. As shown in fig. 6A, such a gradient lens may be sandwiched between a pair of refractive material plates 8 that provide support, protection and possibly also cooling for the lens.

Fig. 7, 7A and 7B illustrate various matrix arrays of cylindrical lenses 25. The relationship between the length 26 and the diameter 27 of the cylindrical lens 25 can vary as shown in the figures. The cylindrical lens 25 of fig. 7A and 7B provides line focusing, rather than point or circle focusing as with the previously shown arrays.

Fig. 8-8C are cross-sectional views of one layer of a cylindrical lens matrix system. The incident beam 11 is refracted by a cylindrical lens 25 (fig. 8 and 8A) or a half cylindrical lens 29 (fig. 8B and 8C) and focused to a line focus 28. In fig. 8B and 8C, the cylindrical lens 29 is in the impregnating material 16. The primary optical working surface 30 and the secondary optical working surface 31 may be spherical or aspherical, which allows for high quality focusing. As shown in fig. 7-8C, the line focus can be oriented in different directions with respect to adjacent lenses, some of which are oriented perpendicular to each other in these figures.

In fig. 9, 9A and 9B, the matrix of focal spots is achieved by passing the incident beam 11 through two layers of cylindrical lenses 32 and 35. Fig. 9A and 9B are cross-sectional views of the array shown in fig. 9, viewed from two orthogonal directions. By varying the focal length of the first layer lens 32 having surface 33 and the second lens 35 having surface 36, it is possible to achieve a rectangular focal spot of the desired size. The first layer lens 32 and the second layer lens 35 are mounted in the impregnating material 16. Lenses 32 and 35 may be standard optical fibers or may be replaced by cylindrical lenses, either spherical or aspherical. To minimize edge loss, surfaces 34 and 37 may be of optical quality.

Fig. 10 shows a single lens objective 43 with a beam splitter 38. The beam 11 incident on the oblique beam splitter 38 is split through refractive surfaces 41 and 42 of a lens 43 to focus on the central point 39 and the off-center point 40. Surfaces 41 and 42 can be spherical and/or aspherical. A plate 54 with flat optical surfaces 53 and 55 allows a fixed distance to be achieved between the optical surface 55 and the focal points 39, 40. The beam splitter 38 may act as a grating that splits the beam 11 into several beams and provides several focal points.

In fig. 11, the dual lens (43, 46) objective provides higher quality focusing and numerical aperture due to the optical surfaces 41, 42 and 44 being placed in the optimal positions. These surfaces may all be spherical or aspherical. The optical surface 45 of the lens 46 may be planar to increase the numerical aperture and may be in contact with the plate 54. The plate 54 may also be a cooling element as previously discussed.

Fig. 12 differs from the above-described figures in providing a three-lens objective lens (lenses 43, 46 and 49). Fig. 13 shows a four-lens objective system, with optical surfaces 50 and 51 of lens 52 allowing the radius of the treatment area (i.e. the distance between points 39 and 40) to be increased.

Fig. 14, 14A and 14B illustrate three optical systems that may be used as scanning front ends on the various objective lenses shown in fig. 10-13. In these figures, the initial collimated beam 11 is projected on a scanning mirror 62 and reflected by this mirror onto the surface 41 of the first lens 43 of the lens optics. The scanning mirror 62 is designed to move the optical axis 63 over an angle f. An angular displacement of the normal 64 of the mirror 62 by an angle f will cause the angle of the beam 11 to change by an angle 2 f. The optical position of the scanning mirror 62 is at the entrance pupil of the focusing objective. To better establish the correlation between the diameter of scan mirror 62 and the radius of the working surface (i.e., the distance between points 39 and 40) and improve focus quality, lens 58 may be inserted in front of scan mirror 62 as shown in FIG. 14A. The optical surfaces 56 and 57 of the lens 58 may be spherical or aspherical. For additional aberration control, a lens 61 may be interposed between the lens 58 and the mirror 62, the lens 61 having optical surfaces 59 and 60.

Fig. 15, 15A and 15B are similar to fig. 14, 14A and 14B except that the light source is a point light source or optical fiber 65 instead of a collimated beam 11. A light beam 66 from a point source (e.g., fiber end) 65 is incident on the scanning mirror 62 (fig. 15) or the surface 57 (fig. 15A, 15B) of the lens 58.

FIGS. 16 and 16A show an A two mirror scanning system. In the simpler case shown in fig. 16, the scanning mirror 67 rotates within an angle f2 and the scanning mirror 62 rotates within an angle f 1. Beam 63 is initially incident on mirror 67 and is reflected by mirror 62 onto mirror 67 and then onto surface 41 of optical lens 43. In fig. 16A, an objective lens 106 is inserted between the two mirrors in order to increase the numerical aperture of the focused beam, to increase the working area on the skin and to reduce aberrations between the scanning mirrors 62 and 67. Although a simple lens objective 106 is shown in this figure, a more complex objective may be used. Objective lens 106 refracts the beam from the center of scanning mirror 67 to the center of scanning mirror 62.

In fig. 17, scanning is accomplished with a scanning lens 70 that is movable in direction s. When scanning lens 70 is moved to an off-center position 73, optical surface 68 refracts light along optical axis 71 into direction 72.

In fig. 18, scanning is accomplished with rotating lens 76 (e.g., to position 77). Surface 74 is planar and surface 75 is selected such that it does not affect the direction of refractive optical axis 72. In fig. 19, scanning is accomplished by moving the point source or fiber 65 in the direction s.

Fig. 20 and 21 show zoom lens objectives that move the damage islands to different depths. In fig. 20, the first member is composed of a single lens 81 movable along the optical axis relative to a second member composed of two lenses 84 and 87, which is immovable. A lens 84 is used to increase the numerical aperture. To increase the numerical aperture, the range of the back focal length and to reduce the focal spot size, the optical surfaces 79, 80, 82, 83 and 85 may be aspherical. The relative position of the first and second components determines the depth of focal spot 12.

FIG. 21 shows a zoom lens objective with spherical optical surfaces. The first part consists of a single lens 90 which is movable along the optical axis relative to the second part. The second, non-movable part consists of five lenses 93, 96, 99, 102 and 105. The radii of curvature of the surfaces 88 and 89 are selected to compensate for aberrations of the immovable second part. Furthermore, the depth of focus may be controlled by controlling the distance between the first and second parts. Any of the lens systems illustrated in fig. 20 and 21 may be mounted to be movable, either manually or under the control of the control device 218, to selectively focus on a desired portion 214 of the target volume V or to indiscriminately focus on various portions of the target volume.

While the present invention has been particularly shown and described with reference to various embodiments, and while changes in these embodiments have been discussed, the embodiments are provided by way of illustration and example only, and changes in form and details can be made therein by one skilled in the art without departing from the spirit and scope of the invention which is defined solely by the claims.

Claims (27)

1. An apparatus for performing a treatment on a volume located at an area and depth coordinate of a patient's skin, the apparatus comprising:

a radiation source;

a mechanism for cooling the patient's skin at the zone coordinates to a selected temperature; control means for selectively operating said mechanism to pre-cool said skin for a selected duration during application of radiation; and

an optical system for applying radiation from said radiation source, said optical system concentrating said radiation to a depth in said volume and to selected regions of said volume so as to define spatially separated three-dimensional treated portions, said treated portions being smaller than said volume, each of said portions being substantially surrounded by untreated skin.

2. The apparatus of claim 1, wherein: the optical system includes a depth-adjustable optical focusing element and a positioning mechanism for the optical focusing element that moves the element over successive processing sections for focusing.

3. The apparatus of claim 1, wherein: the optical system concentrates the radiation to at least one depth in the volume and a selected region of the volume that define a three-dimensional treated portion of the untreated portion within the volume, and applies the radiation to the optical concentration element to sequentially illuminate more than one three-dimensional treated portion.

4. The apparatus of claim 1, wherein the optical system comprises an array of optical elements, each optical element focusing radiation to a depth and selected region within the volume to define a plurality of three-dimensional treated portions in untreated portions of the volume; and is

Wherein the optical system further comprises control means for selectively causing radiation to irradiate the three-dimensional treatment portion.

5. The apparatus of claim 1, wherein the apparatus continuously directs radiation to the array of optical elements; and is

Each optical element in the array directs radiation to at least one depth and selected area within the volume, the at least one depth and area defining N treatment portions within the volume, N ≧ 1.

6. The apparatus of claim 1 wherein said optical system comprises a multi-focusing optical system to which radiation from said radiation source is applied, said multi-focusing optical system applying said radiation to at least one depth in said volume and at a selected region of said volume, said at least one depth and said region defining a treated portion of a three-dimensional space within an untreated portion of said volume in said volume.

7. The apparatus of claim 6, wherein the ratio of said treatment portion to said volume is between 0.1% and 90%.

8. The apparatus of claim 7, wherein said ratio is 10% to 50%.

9. The apparatus of claim 8, wherein said ratio is 10% to 30%.

10. The apparatus of claim 6, wherein said treated portion of said volume is one of a cylinder, sphere, ellipsoid, solid cuboid, and plane of selected size and thickness separated by a selected distance.

11. The apparatus of claim 6 wherein said processed portion of said volume is interleaved of selected lengths and thicknesses.

12. The apparatus of claim 6, wherein said multi-focus optical system comprises an array of a plurality of optical elements to which radiation from said radiation source is to be applied at least simultaneously, each optical element in said array concentrating said radiation to a selected treatment portion of said volume.

13. The apparatus of claim 12, wherein each optical element in said array is focused to a row of selected length and thickness, the rows for some of said elements being at selected angles relative to the rows for others of said elements.

14. The apparatus of claim 6 wherein said multi-focus optical system includes means for scanning radiation applied to an optical concentrating element to concentrate said radiation successively into N of said processing portions, where N ≧ 1.

15. The apparatus of claim 6, wherein said multi-focus optical system comprises an adjustable depth optical focusing element and a positioning mechanism for said optical focusing element that moves said element to focus on successive treatment portions.

16. An apparatus as set forth in claim 6 including means for cooling a portion of the patient's skin to a selected temperature at least at said selected area coordinates and control means for selectively operating said means to pre-cool said portion of the patient's skin for a selected duration at least one of prior to and during the application of the radiation.

17. An apparatus according to claim 16, wherein said mechanism and control means precool said skin to a temperature and for a time sufficient to cool said portion of skin to at least a selected temperature below normal body temperature at least at said at least one depth.

18. The device of claim 16, wherein said skin is cooled to a depth below said at least one depth to at least said selected temperature, whereby each of said treatment portions is substantially surrounded by cooled skin.

19. The apparatus of claim 6, wherein said radiation source produces radiation of a wavelength that is neither strongly absorbing nor strongly scattering in at least the portion of the patient's skin above said volume.

20. The apparatus according to claim 6, wherein said multi-focus optical system is focused to a selected depth below said at least one depth for achieving said depth focusing in the patient's skin with respect to a relatively deep depth coordinate.

21. An apparatus as claimed in claim 6, including a detector for at least one selected condition in at least one of said volume and a portion of the patient's skin above said volume, said multi-focus optical system being operative in response to said detector to control the treatment portion of said volume which is irradiated with said concentrated radiation.

22. An apparatus for performing a treatment on a volume located at an area and depth coordinate of a patient's skin, the apparatus comprising:

a radiation source;

a mechanism for cooling the patient's skin at the zone coordinates to a selected temperature;

control means for selectively operating said mechanism to pre-cool said skin at least prior to and during application of radiation for a selected duration, said mechanism and control means being cooled to a temperature and for a duration sufficient to cool said skin at least to a selected sub-normothermic temperature and at least to a depth below said depth coordinate; and

a multi-focal optical system for applying radiation from said radiation source, said multi-focal optical system concentrating said radiation to a depth in said volume and to selected regions of said volume so as to define spatially separated treatment portions, said treatment portions being smaller than said volume, each of said portions being substantially surrounded by untreated and cooled skin.

23. The apparatus of claim 22, wherein said radiation is applied to said multi-focus optical system for a duration greater than the thermal relaxation time of each section.

24. The apparatus of claim 22, said radiation having a selected wavelength and being concentrated on a plurality of selected, three-dimensionally located treatment portions, wherein said treatment portions are within non-treatment portions.

25. The device of claim 22, wherein

The treated portion of the three-dimensional treated portion of each volume is one of a cylinder, sphere, ellipsoid, solid cuboid, or plane of selected size and thickness and spaced apart by a predetermined distance.

26. The apparatus of claim 22 wherein the optical system comprises an array of optical elements, radiation from the radiation source being applied simultaneously to at least one of the more than one optical element, the optical elements causing the radiation from the radiation source to be focused at more than one focal point so as to cause the radiation to converge at least one depth within the volume and at a selected region within the volume, the at least one depth and the region defining a three-dimensional treated portion of the volume within an untreated portion, each optic converging the radiation at the selected treated portion within the volume.

27. The apparatus of claim 22, wherein the optical system comprises an array of optical elements to which radiation from the radiation source is applied simultaneously to at least one or more of the optical elements, the optical elements causing radiation from the radiation source to be focused at least one depth within the volume and at a selected region within the volume, the at least one depth and the region defining a three-dimensional treated portion of the volume within an untreated portion, each optical element focusing radiation to a selected treated portion within the volume;

wherein said three-dimensionally processed portion of said volume is one of a cylinder, sphere, ellipsoid, solid cuboid, or plane of selected size and thickness and spaced apart by a predetermined distance;

the ratio of the treated portion to the volume is between 0.1% and 90%.