Diagnostics of a laser-induced response of capillary vessels in tissues

The effect of 675-nm semiconductor laser radiation of various power densities on the degree of oxygenation and the relative concentration of hemoglobin in blood in the microcirculatory vessels in the skin of a hand is studied in vivo by the spectroscopy of backward diffuse reflection in the visible range. No noticeable variations in these quantities were observed at relatively low power densities (up to 0.5 W cm-2) of the radiation power density. At higher power densities, an increase in the degree of oxygenation and the relative concentration of hemoglobin was observed, which is apparently caused exclusively by heating.