Abstract:
An apparatus for applying targeted phototherapy to a skin treatment area includes a UVB module arranged to output light at about 308 nm having at least one flash lamp arranged to generate light including UVB light and a UVB transmissive window for transmitting UVB light generated by the flash lamp, a user interface, and a controller configured to detect when the user interface is actuated and to cause pulsing of the flash lamp in response to the actuation of the user interface. A method of applying targeted phototherapy to a skin treatment area includes contacting a phototherapy apparatus with the skin, the apparatus including at least one flash lamp and a UVB transmissive window, such that the window is positioned in alignment with the treatment area, and activating the flash lamp to cause pulsed UVB light at 308 nm to be transmitted through the window.

Description:
BACKGROUND 
       [0001]    The present disclosure relates to phototherapeutic treatment of the epidermis, and more particularly to targeted ultraviolet therapy for treatment of skin conditions. Specifically, methods and apparatus for targeted narrow-band UVB phototherapy are disclosed to adjunctively treat dermatoses (e.g., psoriasis, vitiligo, leukoderma, atopic dermatitis, and alopecia greata). 
         [0002]    Approximately 2% of people worldwide have psoriasis, and a lesser but still large percentage have vitiligo and other skin conditions. The condition of psoriasis ranges from mild to severe. It can lead to substantial morbidity and psychological stress and have a profound negative impact on a patient&#39;s quality of life. Although available therapies reduce the extent and severity of the disease and improve quality of life, reports have indicated patient dissatisfaction with the effectiveness and inconvenience of current treatment modalities. 
         [0003]    A common treatment modality for patients with psoriasis or vitiligo is to receive phototherapy administered in phototherapy centers. Patients are exposed to narrowband (NB) or broadband (BB) ultraviolet light B (UVB) or a therapy of psoralen plus ultraviolet light A (PUVA). Psoriasis patients require three or more sessions per week for approximately 30 treatments, and vitiligo patients require even more treatments. The use of phototherapy can be limited by travel distance from a phototherapy center and poor compliance to the necessary regimen of regular treatment sessions. Adjunctive therapies (e.g., topical prescriptions, over-the-counter topical creams) may improve the efficiency of phototherapy, but do not remove the necessity for phototherapy itself. 
         [0004]    Ultraviolet light improves the symptoms of psoriasis through immunomodulatory mechanisms. The treatment of atopic dermatitis and alopecia greata with UV light has also been studied but not to the same degree; however, similar immunomodulatory mechanisms are likely. Leukoderma and vitiligo rely on the UV light to help re-pigment the skin because of a lack of melanin/melanocytes. 
       SUMMARY 
       [0005]    In one embodiment, a phototherapy apparatus is described for applying targeted phototherapy to a treatment area on human skin. The apparatus includes a UVB module arranged to output UVB light at about 308 nm. The UVB module has at least one flash lamp arranged to generate light including UVB light and a UVB transmissive window for transmitting UVB light generated by the at least one flash lamp. A user interface, which may include but is not limited to a pushbutton, is provided. A controller is configured to detect when the user interface is actuated and to cause pulsing of the at least one flash lamp in response to the actuation of the user interface. 
         [0006]    In one variation, the phototherapy apparatus may include at least one sensor, and the controller may be configured to regulate one or more of the intensity, pulse rate, and pulse duration of the at least one flash lamp based on a signal from the at least one sensor. The sensor can include one or more of a melanin level sensor, an erythema sensor, a radiometer, and an infrared thermometer. 
         [0007]    The at least one flash lamp may be configured to generate narrow-band UVB light that is transmissible through the window. Alternatively, the UVB module may further include a UVB band-pass filter adjacent to or incorporated into the window, and the at least one flash lamp may be configured to generate broad-band light including UVB light that is transmissible through the window and band-pass filter. The UVB module may include a reflective shield configured to redirect the UVB light generated by the at least one flash lamp through the window. 
         [0008]    A contact sensor may be provided, and the controller configured to detect whether the contact sensor indicates that the apparatus is in contact with the skin of a user and to disable pulsing of the at least one flash lamp when the apparatus is not in contact with the skin of a user. 
         [0009]    A cooling device may be provided that can be removably mounted to the UVB module to provide cooling to the skin surrounding the treatment area. Additionally, a removably mounted aperture may be provided to focus the UVB light to a treatment area having a desired shape and size. 
         [0010]    In another embodiment, a method of applying targeted phototherapy to a treatment area on human skin includes contacting a phototherapy apparatus with the human skin, the phototherapy apparatus including at least one flash lamp and a UVB transmissive window, such that the window is positioned in alignment with the treatment area. The method further includes activating the at least one flash lamp to cause pulsed UVB light at 308 nm to be transmitted through the window. 
         [0011]    In one variation, the method further includes sensing at least one parameter and regulating one or more of the intensity, pulse rate, and pulse duration of the at least one flash lamp based on the sensed at least one parameter. The parameter may be one or more of melanin level, erythema, radiation emitted by the flash lamp, and temperature of the treatment area. 
         [0012]    The method may further include detecting whether the apparatus is in contact with the skin of a user and disabling pulsing of the at least one flash lamp when the apparatus is not in contact with the skin of a user. Additionally, the skin surrounding the treatment area may be cooled during pulsing of the at least one flash lamp. 
         [0013]    In another embodiment, a phototherapy apparatus is described for applying targeted phototherapy to a treatment area on human skin. The apparatus includes a UVB module arranged to output UVB light at about 308 nm. The UVB module has at least one flash lamp arranged to generate light including UVB light, a UVB transmissive window for transmitting UVB light generated by the at least one flash lamp, at least one sensor selected from the group consisting of a melanin level sensor, an erythema sensor, a radiometer, and an infrared thermometer, and a contact sensor. The apparatus further includes a user interface and a controller configured to detect when the user interface is actuated and the contact sensor indicates that the apparatus is in contact with the skin of a user, to cause pulsing of the at least one flash lamp in response to the actuation of the user interface, and disable pulsing of the at least one flash lamp when the apparatus is not in contact with the skin of a user. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The foregoing, as well as the following detailed description of the embodiments, will be better understood when read in conjunction with the appended drawings. For the purpose of illustration, there are shown in the drawings some embodiments which may be preferable. It should be understood, however, that the embodiments depicted are not limited to the precise arrangements and instrumentalities shown. 
           [0015]      FIG. 1  is a front/side perspective view showing an embodiment of a hand-held UV phototherapy apparatus. 
           [0016]      FIG. 2  is a front/side exploded perspective view of an embodiment of a hand-held UV phototherapy apparatus. 
           [0017]      FIG. 3  is a side/front perspective view of an embodiment of a hand-held UV phototherapy apparatus with a removable cooling device positioned around the periphery of the treatment area. 
           [0018]      FIG. 4  is a front perspective view of an embodiment of an removable aperture for mounting on a hand-held UV phototherapy apparatus. 
           [0019]      FIG. 5  is a block diagram depicting control components of an embodiment of a hand-held UV phototherapy device. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    A hand-held UVB phototherapy device is disclosed herein which can be used for home administered maintenance phototherapy. Home administered therapy can be use to treat various dermatoses, including psoriasis, vitiligo, leukoderma, atopic dermatitis, and alopecia greata. Home administered therapy may help to maintain remission once professional in-center treatment regimen has ended, or may be used to increase the time between professional in-center treatments. A hand-held UVB therapy apparatus provides targeted phototherapy, which spares healthy tissue from long-term cumulative UV exposure. 
         [0021]    An embodiment of a UVB phototherapy apparatus  10  is depicted in  FIG. 1 . In the depicted embodiment, the apparatus  10  includes a housing  12  containing electronic components (not shown) for powering and controlling the apparatus  10 , a power cord  11  for supplying power to the electronic components, and a removable UVB module  20  that includes one or more flash lamps  22  for generating broad-band or narrow-band UVB light. 
         [0022]    A front cover  16  on the UVB module includes a bezel  17  surrounding a window  18  for transmitting UVB light generated by the one or more flash lamps  22  located within the UVB module  20  behind the window  18 . The front cover  16  defines a contact surface of the apparatus  10  for contacting the skin of a patient to be treated. The window  18  is made from a UVB transmissive material and may serve as a UVB band-pass filter to block the transmission of other non-therapeutic wavelengths of light. In particular, the window  18  may include a band-pass filter that allows transmission of only light at about 308 nm. The window  18  enables targeted application of UVB phototherapy to treat dermatoses while minimizing the exposure of healthy skin. 
         [0023]    A user interface  14 , which may be in the form of a pushbutton, is mounted on the housing  12  for operating the apparatus  10 . The user interface  14  can include a momentary contact switch for delivering pulses of light on demand, or for activating a control system that delivers a rapid series of pulses as long as the user interface  14  is actuated. 
         [0024]    An exploded view of the apparatus  10  is shown in  FIG. 2 . The removable front cover  16  is removed to show the UVB module  20  mounted in the housing  12 . The UVB module  20  is positioned behind the window  18  and bezel  17  when the front cover  16  is installed on the housing  12 . 
         [0025]    The UVB module  20  includes the one or more flash lamps  22 . In the depicted embodiment, two flash lamps  22  are provided. The flash lamps  22  are preferably generally cylindrical or tubular lamps of the type that emit light along their length in all directions. The flash lamps  22  emit ultraviolet light that is primarily concentrated in the UVB range of 280 nm to 315 nm, is preferably concentrated within the anti-psoriatic region of 296 nm to 313 nm, and is more preferably concentrated at about 308 nm. 
         [0026]    In one embodiment, the flash lamps  22  are gas-filled lamps that emit a spectrum of ultraviolet light. The gas is preferably a mixture containing a noble gas (e.g., argon, krypton, or xenon) and a halogen (e.g., fluorine or chlorine). In one embodiment, helium and/or neon is used as buffer gas, a halogen gas including primarily xenon chloride (XeCI) is used to produce pulsed light specifically at 308 nm. 
         [0027]    In another embodiment, the flash lamps  22  are filament lamps that emit a broadband spectrum of light. Preferably, the filament is tungsten and the gas is a halogen gas (e.g., fluorine or chlorine). A band-pass filter in or adjacent to the window  18  may be used in conjunction with a broadband filament lamp to limit the light emitted from the device to the UVB range specifically to about 308 nm. 
         [0028]    The UVB module  20  further includes a UVB light reflective shield  24 . The one or more flash lamps  22  are positioned in front of the reflective shield  24  so that the light emitted by the lamps  22  is directed forward, toward (and through) the window  18  and/or band-pass filter. The reflective shield  24  includes several ports  30  in which various sensors can be mounted, including but not limited to a melanin level sensor  32 , an erythema sensor  34 , a radiometer  36 , and an contactless infrared thermometer  38 . The ports  30  are positioned so that, if necessary, any sensors mounted in the ports  30  have a clear optical path through the window  18 . In addition, a spring-actuated contact sensor  40  is provided behind the front cover  16  to sense when the front cover  16  is placed into contact with the skin of a patient. 
         [0029]    As shown in  FIG. 5 , a controller  50  receives input signals from the melanin level sensor  32 , the erythema sensor  34 , the radiometer  36 , the infrared thermometer  38 , the spring-actuated contact sensor  40 , and the user interface  14 , and controls pulsation of the flash lamps  22  via a capacitive pulse unit  52 . The controller  50  and the capacitive pulse unit  52  are powered by a power supply  54 . As shown, the power supply  54  may be powered via an AC power cord  11 , or by a replaceable and/or rechargeable battery so as to make the apparatus  10  more readily portable. 
         [0030]    The controller  50  may regulate or limit the irradiance (intensity/output levels) of the flash lamps  22  based on input signals from one or more of the melanin level sensor  32  and the erythema sensor  34 . The controller may limit the intensity and duration of radiation exposure based on input signals from the infrared thermometer  38 , if skin temperature in the treatment region gets too high. The controller  50  may also include a timer or energy counter so that the dose or fluence emitted by the apparatus  10  can be set in advance, or limited during use. Alternatively, the controller  50  can monitor the lamp output through the radiometer  36  to ensure proper dosing. 
         [0031]    The controller  50  can further be configured to set a flash lamp intensity, a pulse on-time, and a number of pulses per exposure so that both the irradiance (intensity) and fluence (dose) can be optimized for the particular patient and condition being treated. 
         [0032]    Based on input from the contact sensor  40 , the controller  50  limits or prevents firing of the flash lamps  22  unless the front cover  16  is in contact with the skin with sufficient force (minimal) that the contact sensor  40  is actuated. 
         [0033]      FIG. 3  shows the phototherapy apparatus  10  with a cooling device  60  removably mounted over the front cover  16  to provide cooling to the skin around the periphery of the treatment area. The cooling device  60  includes cooling elements  62  adapted to be in contact with the skin and to deliver cooling to the skin, as well as a heat dissipation structure  64  to remove heat from the cooling elements  62 . The cooling elements  62  may be thermoelectric chillers, or may be chilled by another mechanism, including by the flow of liquid or cryogenic coolant. Cooling helps to reduce the skin temperature at and around the treatment area, and helps to control pain so that a full course of treatment can be applied. 
         [0034]      FIG. 4  shows an aperture  70  that can be removably attached to the front cover  16  of the phototherapy apparatus  10  to assist in focusing the UVB radiation on the desired treatment area. The aperture  70 , as shown, includes a base  72 , a rim  74 , a tapered portion  76 , and an opening  80  that is smaller than the window  18  in the front cover  16 . The rim  74  may be used to enable the aperture  70  to attach to or snap onto the front cover  16 , and may engage the bezel  17  or another portion of the front cover  16 . The opening  80  may be of any shape or size. The opening  80  may be completely open, or may include a UVB transparent window or band-pass filter. The aperture  70  may include a reflective inner surface to improve the energy transmission through the opening  80 . 
         [0035]    In operation, the phototherapy apparatus  10  is positioned so that the window  18 , or the opening  80  in the aperture  70  if appropriate, is aligned with an area of the skin to be treated. The front cover  16  (or aperture  70 ) is placed into contact with the skin so that the contact sensor  40  is actuated. The user interface  14  is actuated, and if required held in an actuated state, to activate the controller  50 . The controller  50  sends power to the capacitive pulse unit  52 , which begins pulsing the flash lamps  22  at an intensity, rate, and duration as commanded by the controller  50 . Should the phototherapy apparatus  10  be moved so that the contact sensor  40  is no longer actuated, pulsing of the flash lamps  22  ceases. 
         [0036]    In the case where treatment of fixed duration is to be applied, the user interface  14  need not be held in an actuated state for pulsation of the flash lamps  22  to continue for the fixed duration. In the case where treatment is of variable duration, or manually controlled, release of the pushbutton will cease flashing of the lamps  22 . 
         [0037]    The controller  50  may increase or decrease the intensity, rate, or duration of light pulses based on feedback from the melanin level sensor  32 , the erythema sensor  32 , the radiaometer  34 , and/or the infrared thermometer  36 , as needed, to optimize the effectiveness and minimize the length of the treatment, and to ensure patient safety. 
         [0038]    While reference has been made to specific embodiments, it is apparent that other embodiments and variations can be devised by others skilled in the art without departing from their spirit and scope. The appended claims are intended to be construed to include all such embodiments and equivalent variations.