Oxyhemoglobin photodissociation efficiency in biological tissue exposed to laser radiation

Abstract

We have obtained quantitative data on the differential (with respect to depth) and the integrated oxyhemoglobin photodissociation efficiency in the dermis when the skin surface is exposed to a light beam in the wavelength range 300–650 nm. With this aim, we have used our own previously developed optical model for skin tissue and analytical procedure for calculating the characteristics of optical fields in a medium. We have estimated the number of oxygen molecules formed at different depths in the medium, and also their integrated number over the entire thickness of the dermis as a function of the irradiation wavelength. We consider models for a dermis that is homogeneous with respect to depth and a dermis that has a layered structure. We show that the spectral photodissociation efficiency has a number of maxima associated with the absorption spectrum of oxyhemoglobin and the optical properties of all the layers of skin tissue. We discuss the effect of the epidermis on these maxima.