Narrow Band Ultra Violet B Light is a relatively new technology on the vitiligo front. In the past, most doctors have used the PUVA system, which involved the use of Ultra Violet A light exposure and the taking of Psoralen pills. However, side effects for many people were unbearable. Narrow Band UVB light panels and cabinets solve the problems of over-exposure to ultraviolet by maximizing delivery of narrow-band UVB radiation (in the 311-312 nanometer range, the most beneficial component of natural sunlight) while minimizing exposure to superfluous UV radiation.
This allows patients to receive photo-therapy treatments with less risk of severe burning or pathogenic exposure to UV in harmful ranges. (It also avoids the adverse side effects of the psoralens used in conventional PUVA therapy, since UVB treatment requires no supplemental drugs.) These benefits have made Narrow Band UVB systems increasingly popular with vitiligo patients and their doctors.
Even better is that Narrow Band UVB light systems are available in home-sized panel systems and cabinets, which many are finding far more convenient than frequent trips to their dermatologist’s office. Though many people buy complete surrounding cabinets, some doctors suggest that panels are actually more effective, and that the optimum distance from the bulbs for the area being treated is about 7 inches. Time exposures should be discussed with your dermatologist prior to using a light panel or cabinet, as the exposure times vary greatly depending on how long you have been treating, and your skin tone.
Narrow band UVB reduces superfluous and harmful UV by emitting only wavelengths of 311-312 nanometers. Conventional broad band UVB lamps emit a variety of wavelengths ranging from 280-330 nm. Clinical studies show the peak therapeutic effectiveness of UVB to be within the range of 295-313 nm, but wavelengths below 300 nm can cause erythema or severe burning and increase the risk of skin cancer. The 311-312 range is considered by many to afford optimum safety.
Edited and copied from http://www.homephototherapy.com/nbc-narrowband.htm