Method of quantitative estimation of the absorbed energy of low-intensity electromagnetic ra-diation used in phototherapy

Abstract

The study of the distribution of low-intensity electromagnetic radiation of the visible range in human skin, for quantitative assessment tasks and the forecast of the expected effect of the phototherapy procedure is carried out. An analysis of the sources of visible electromagnetic radiation used in phototherapeutic equipment, taking into account their lighting and energy characteristics, is carried out. Based on biophysical models of the epidermis, dermis and the layer of subcutaneous fat, an optical model of the human skin is synthesized, taking into account the physical characteristics of each layer. Based on the Monte Carlo method, a probabilistic model of the behavior of the photon flux in the layers of the skin, which depends on the wavelength of the radiation, is developed and implemented. The developed model allows to take into account the individual features of the skin: the thickness of each layer, the amount of melanin, the intensity of cutaneous blood flow. Investigations of this model made it possible to obtain radiation absorption / transmission diagrams depending on the wavelength for each layer and the entire skin. The obtained research data made it possible to determine the dependence of the reflection coefficient upon changing the wavelength and the angle of inclination of the incident photon beam, as well as the absorption coefficient of various layers of the skin, and a map of the distribution of the absorbed radiation power density within each layer at different wavelengths of electromagnetic radiation.