Short Wavelength UV Sources for Treatment of Psoriasis

描述（由申请人提供）：项目摘要/摘要：研究工作将集中在制造紫外线（UV）发光二极管（LED）的发射范围为305 nm至315 nm的光疗银屑病。成功生产该波长范围内的UV源将能够研究新的光疗治疗方案，用于银屑病和可能的其他皮肤病，包括寻常痤疮、特应性皮炎、白癜风、瘙痒症、扁平苔藓、玫瑰糠疹和早期皮肤T细胞淋巴瘤。为了设计和实施有效的光治疗，特定波长和功率密度的紫外线源必须在清除银屑病的作用光谱内可用。短于295 nm的波长在较高剂量下产生光毒性，对银屑病没有积极作用。在315 nm以上的波长下，与皮肤组织的反应大大减少，与UVB相比，UVA区域中的暴露需要约1000倍的剂量，在小暴露部位观察到非常有限的成功。这表明，在特定波长的单色辐射可能比暴露于宽带源更具治疗性。紫外线范围内的所有光疗都受到邻近受影响区域的正常未受累皮肤上的有害辐射暴露的限制，并且需要严格控制波长、剂量、分布和输送。UV光源是用于治疗特定皮肤疾病（例如牛皮癣）的光疗中的核心使能技术。如今，这些光源主要是宽带高压汞灯、汞氙、汞氩和氘源或准分子激光器。在实践中，这意味着光疗治疗方法必须适应可用的光源波长，而不是将光源优化为感兴趣的特定波长。该提案专注于基于氮化铝镓（AlGaN）合金的LED的开发，该合金可以覆盖UV光谱的大部分和有用部分。这些半导体器件结构紧凑（大约一粒米的大小），寿命长，稳定，需要简单的驱动电子设备。每个器件都具有窄的发射光谱，其通过在制造期间调整器件的有源层的组成和结构来调谐。因此，UV LED的组合可以在它们覆盖的波长范围内提供特定的、可选择的光谱（通过电子控制）。宽带UVB、窄带UVB、宽带UVA、光化学疗法（PUVA）和光动力疗法（PDT）是其中需要UV源的应用之一。项目叙述：在305 nm至315 nm（UVB）范围内发射的基于氮化物的UV LED可以成功地用于某些疾病和皮肤病的光疗。该波长范围已被证明对治疗牛皮癣有效。现有的银屑病光疗治疗是昂贵和耗时的，并且可以干扰就业或学校的时间表。存在这样的需求，其中可以为患者开具基于305 nm至315 nm LED的廉价紧凑型UV设备，以用于治疗银屑病的家庭使用。

DESCRIPTION (provided by applicant): Project Summary/Abstract: Research efforts will focus on fabrication of ultraviolet (UV) light emitting diodes (LEDs) in the emission range of 305 nm to 315 nm for phototherapy of psoriasis. Successful production of UV sources in this wavelength range will enable research for new phototherapy treatment programs for psoriasis and possibly other skin diseases including acne vularis, atopic dermatitis, vitiligo, pruritus, lichen planus, pityriasis rosea and early cutaneous T-cell lymphoma. To design and implement effective light treatments, UV sources at specific wavelengths and power densities have to be available within the action spectrum for clearing psoriasis. Wavelengths shorter than 295 nm produce phototoxicity at higher doses with no positive effect on the psoriasis. At wavelengths above 315 nm, reactions with the skin tissue is greatly reduced, with exposure in the UVA region requiring about 1000 times the dose compared to UVB with very limited success observed on small exposure sites. This suggests that monochromatic radiation at specific wavelengths may be more therapeutic than exposure to broadband sources. All phototherapy in the UV range is limited by injurious exposure to radiation on normal uninvolved skin adjacent to the affected areas and strict control of wavelength, doses, distribution and delivery are required. UV light sources are a core enabling technology in phototherapy for treatment of specific skin diseases such as psoriasis. Today, these light sources are primarily broadband high pressure mercury lamps, mercury xenon, mercury argon and deuterium sources or excimer lasers. In practice, this has meant that phototherapy treatment methods have had to be adapted to the available light source wavelengths rather than optimizing the light sources to specific wavelength(s) of interest. This proposal concentrates on the development of LEDs based on aluminum gallium nitride (AlGaN) alloys that can cover a large and useful portion of the UV spectrum. These semiconductor devices are compact (about the size of a grain of rice), stable over long lifetimes, and require simple drive electronics. Each device has a narrow emission spectrum that is tuned by adjusting the composition and structure of the active layers of the device during manufacture. Thus, a combination of the UV LEDs can deliver a specific, selectable spectrum (via electronic control) over the wavelength range they cover. Broadband UVB, narrow band UVB, broadband UVA, photochemotherapy (PUVA) and photodynamic therapy (PDT) are among the applications in which UV sources are required. Project Narrative: Nitride based UV LEDs emitting in the 305 nm to 315 nm (UVB) range can be successfully employed in phototherapy of certain illnesses and skin diseases. This wavelength range has proven effective in treating psoriasis. Existing psoriasis phototherapy treatments are costly and time consuming and can interfere with employment or school schedules. A need exists in which an inexpensive compact UV apparatus based on 305 nm to 315 nm LEDs can be prescribed to a patient for in-home use for the treatment of psoriasis.