Noncontact measurement of thermal and optical parameters of biological tissues and materials using IR laser radiometry

A technique for simultaneous measurements of the thermal diffusivity, specific heat, and effective absorbtion coefficient was developed. The technique is based on local heating of a sample by laser radiation and thermal imager measurement of the temperature field dynamics in the surface layer in both the heating and cooling stages. The technique includes a program for calculating the laser-induced temperature field in the sample volume and the determination of three parameters by the Levenberg-Marquardt algorithm to provide the best fit of calculations to experimental results. The statistical error of thermal diffusivity, specific heat, and effective absorbtion coefficient measurements was 5–6%. The technique efficiency was demonstrated by the example of the development of a thermal and optical equivalent of cartilage tissue, based on polyacrylamide hydrogel.