الفهرس 
Ultraviolet radiationOnly 14 pages are availabe for public view
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Abstract
Ultraviolet (UV) radiation has been used for decades with increasing rate and great success in the management of skin diseases. It becomes an essential part of modern dermatologic therapy. For phototherapy, irradiation devices emitting either long wave (UVA, 315 - 400 nm) or middle wave (UVB, 290 - 320 nm) radiation are employed. (Krutmann and Morita, 1999) UVB radiation is divided into a narrow band and broad band. Narrow band UVB phototherapy uses a special lamp (the Philips TL01 lamp), which is virtually a monochromatic source, with a peak narrow band emission at 312nm and a minor peak at 305nm, thereby omitting, the shorter more erythemogenic and carcinogenic wave lengths (Clark et al, 2000).
NB-UVB radiation is absorbed by DNA and urocanic acid. It’s alters the antigen-presenting cell activity, lower natural killer cell activity and lymphoproliferation and produce immunoregulatory cytokines by both Th1 (IL2, IF) and Th2 (IL –10) T cell populations. The ability of NB-UVB radiation systemically to depress major components of cell-mediated immune function is thus likely to be linked to its beneficial effect in several skin diseases (Bilsland et al, 1997). NB-UVB allows the patients to recieve phototherapy with longer remission, lower risk of UV-carcinogenesis and lower incidence of burning or pathogenic exposure to more harmful broad band UVB (range 290-320nm). NB-UVB also avoids the adverse effect of psoralen drugs used in PUVA therapy and can be used in children and pregnant women (Diedern et al, 2003).
NB-UVB is recommended as effective and safe therapy for various skin diseases such as psoriasis, vitiligo, atopic dermatitis, mycosis fungoides and as desensitizing treatment for photodermatoses.