The impact of thermally significant blood vessels in perfused tumor tissue on thermal dose distributions during thermal therapies

This study demonstrates the effects of thermally significant blood vessels on thermal lesion sizes during thermal therapies. The thermal model combines the Pennes [1] bio-heat transfer describing for perfused tissue and the energy equation for blood vessel. A finite difference method was used to solve the transient equation of heat transfer in perfused tumor tissue with a blood vessel in cylindrical coordinates. The thermal dose distribution was determined by the formulation proposed by Sapareto and Dewey [2]. Simulation results quantitatively show that the blood vessel diameter and the averaged blood velocity are the crucial factors determining the thermal dose distribution near the blood vessel for thermal therapies. When a blood vessel diameter passing throughout the heated volume is larger than 1 mm, the thermal dose level may become too low and then lose its hyperthermia effect. (C) 2003 Elsevier Science Ltd.