LIGHT DOSIMETRY - EFFECTS OF DEHYDRATION AND THERMAL-DAMAGE ON THE OPTICAL-PROPERTIES OF THE HUMAN AORTA

The influences of dehydration and thermal damage on in vitro optical properties of human aorta were studied. The absorption coefficient increased by 20-50%, especially in the visible range when at least 40% of total tissue weight was lost as a result of dehydration. The reduced scattering coefficient increased by 10-45% in the visible and 30% to over 150% in the near IR after the tissue samples were heated in a constant temperature water bath at 100-degrees-C for 300 +/- 10 s. This study implies that dehydration and protein coagulation during photothermal treatment of tissue are important factors altering optical properties of tissue.