A predictive analysis of thermal effects in pigmented skin and underlying tissues during IR laser therapy

F. Rossi, R. Pini, G. Romano, F. Cialdai, F. Fusi, M. Monici
Energy for Health [12], 2014

Infrared lasers are widely used in sport medicine and rehabilitation for their ability to induce a selective heating of localized portions of tissue. The desired effect is optimized by varying laser parameters (wavelength, emission modality, power). In this work we present a modelling study aimed at analyzing the thermal effects in the skin in dependence of irradiation conditions (treatment time and scanning mode of the laser probe) and skin pigmentation. The modelling study has been supported by a preliminary experimental study in albino and black mice. The results highlighted the dependence of the temperature values reached in different types of skin, on the concentration of epidermal melanosomes: the same laser induced thermal effects below the threshold of thermal damage in a light pigmented skin (45°C for a 5s arthrosis treatment) and might induce thermal damage in a dark pigmented skin (65°C in the same conditions). Moreover, it has been found out that the scanning mode of the laser light may be modulated in order to induce different thermal regimens in the skin (outer layers and deep layers). This predictive analysis may be used as an effective tool to draft guidelines for laser therapies as well as to design personalized clinical protocols.