ABSTRAKT

The objective of this paper is to analyze the temperature distributions and heat affected zone in skin tissue medium containing inhomogeneties when irradiated with a mode-locked short pulse laser source focused directly at the tumor site using a converging lens. A three-layered tissue phantom model of skin consisting of epidermis, dermis, and fatty tissues underneath is considered. Tumors are simulated with inhomogeneities embedded inside the tissue phantoms. Experimental measurements of axial and radial temperature distribution for single-layer and three-layer phantoms are compared with numerical modeling results obtained using traditional Fourier parabolic and non-Fourier hyperbolic heat conduction formulations. Experimentally measured temperature profiles match extremely well with the prediction from the non-Fourier formulation than the Fourier formulation. It is observed that laser beam focused at the tumor location produced the desired temperature rise with lesser heat spread than a collimated laser beam. Effect of variation of laser parameters on radial temperature distribution is also studied experimentally and numerically. Experiments are also conducted with freshly excised skin tissue samples from mice. The experimentally measured temperature distributions in skin tissue samples upon laser irradiation are also in good agreement with the non-Fourier hyperbolic heat conduction formulation by considering skin as a layered medium having different optical properties in each layer.