Evaluation of temperature distribution during hyperthermic treatment in biliary tumors: a computational approach

A computational approach is adopted to predict the temperature distribution in the biliary tissue during hyperthermic treatments in biliary tumors. Two different models are developed: an axisymmetric model and a three-dimensional model. In the first model the Pennes bioheat transfer equation is applied. It is aimed at simulating the thermoregulatory effect of the capillary bed and it can also give a pressure criterion to determine whether the blood perfusion term should be included in the mathematical model. The second model is aimed at simulating the convective effect of the large hepatic vessels: A constant Nusselt number is assumed on the sides of the vessels. The simulations of the three-dimensional model have been carried out with and without capillary perfusion in the tissue, i.e., respectively in the worst case and in the best case that may occur during heating. The results show that it is possible to obtain therapeutic temperature values in the tissue for time intervals considered acceptable by physicians. Moreover, the model is able to give more precise information about the volumes of tumoral tissue heated above therapeutic temperatures with the hyperthermic technique considered.