Identificação da decomposição térmica de tecidos biológicos em tratamentos por ablação a laser

Abstract

This work presents a computational analysis of the thermal decomposition of biological tissues heated by a laser. This phenomenon is analyzed in terms of the bioheat transfer equation in its enthalpy form. Different mechanisms of thermal decomposition were considered in the problem formulation, such as water vaporization, coagulation and tissue necrosis, besides tissue removal due to the thermal ablation. The Finite Volume Method was used to obtain the numerical solution of the temperature field while the Volume of Fluid method was used to track the ablation interface. Some models to estimate the thermal damage in tissues and cells were used and compared. The results of the direct problem obtained with the computational code developed in this work were verified and validated with experimental results available in the literature, providing a good indication of the region removed by the thermal treatment. The solution of the inverse problem was obtained with ABC SMC algorithm considering intrusive and non-intrusive thermal damage synthetic measured data. For non-intrusive measurements, the algorithm was capable of correctly selecting the model used to generate the simulated data, depending on the measurement uncertainty. For intrusive measurements, both models analyzed could properly represent the thermal decomposition region.