After listening to the introduction of the doctor, do you think that the narrow-spectrum medium-wave ultraviolet (NB-UVB) home light therapy is really simple, the treatment mechanism is like basking in the sun, the equipment operation is equivalent to using the microwave oven to heat the dish, set a time, a key to start can be done. So why not bask in the sun and sunbathe a few times instead of spending energy on light therapy? What is the difference between sun exposure and UV light therapy?
The energy distribution of sunlight is different, visible light and infrared account for more than 93%, ultraviolet light is only about 7%, such as the use of sunbathing treatment, ultraviolet light intensity is relatively weak, long irradiation time, side effects are obvious, the effect is not good. The peak spectrum of ultraviolet phototherapy is NB-UVB of about 311 nm, which is the most effective band for treating diseases such as vitiligo; the solar spectrum is complex, including ionizing radiation and non-ionizing radiation, and some of these light waves may even induce or aggravate the disease.
Phototherapy involves many esoteric theoretical and licensing reviews of photobiology, light therapy, light protection, medical device manufacturing and applications, and so on. For light therapy, it is necessary to take the theory of photobiology and skin biology as the guide to guide the design of the program and the practice of operation, otherwise it will backfire. Over the years, relevant scholars have been studying and exploring new light source and light therapy solutions to make light therapy more effective, more convenient and safer.
The efficacy of phototherapy depends on the dose of a single dose of radiation and the cumulative dose, that is, the regular arrangement and implementation of the light therapy course. How to control the appropriate dose of light therapy is still a practical clinical problem. The initial dose accuracy is of decisive significance for the efficacy, if the first dose does not meet the expected requirements, even if the dose is increased according to the routine, it is not easy to obtain good efficacy, and strive to achieve the desired erythema reaction after 1 to 2 treatments, and do not produce a stronger reaction and affect the continuation of treatment.
Not only are the sensitivities of different individuals or different parts of the same individual to ultraviolet rays and physiological pathological states very different, but also ultraviolet phototherapy has a phenomenon of light adaptation. When illuminating continuously, the dose should be adjusted before each illumination according to whether erythema has occurred and to what extent it has occurred after the last treatment, and if possible, different parts can be adjusted accordingly. Adjusting the dose according to the erythema reaction is enough to exert the effect and avoid light tolerance, but once the erythema response is wrongly judged, the dose increase is prone to overreaction, resulting in discomfort and the need to stop treatment or even aggravate the damage.
The final outcome of phototherapy depends on the total number of treatments. Although the higher illumination frequency can shorten the treatment cycle to reach the cumulative dose, perceive the treatment effect faster, and increase the confidence of patients, but the desire is not reached. It is necessary to treat in strict accordance with the regular treatment plan, the frequency is appropriate, avoid irregular treatment behavior, and cannot be illuminated multiple times a day continuously or in the same part for 1 day because of the pursuit of early results or lack of illumination and missing illumination, and the interval time must be > 24 hours.
Because light can lead to photoaging and photocarcinogenesis, oncology and dermatologists advocate light protection. However, there is no clinical evidence to date that NB-UVB phototherapy increases the risk of skin tumorigenesis. Even if ultraviolet rays hit normal skin, it is not necessarily a bad thing, the therapeutic effect of light therapy on "normal" skin, and for active patients, the therapeutic effect on non-lesion areas or the control of new skin lesions in "normal" areas. However, try to avoid or reduce the damage of light therapy to normal skin.
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