Radiofrequency Ablation With a Gaussian Heat Source in a Realistic Reconstructed Hepatic Geometry

This study describes a detailed methodology for modeling a three-dimensional radiofrequency ablation procedure using reconstructed porous tissue geometries. In this study, MRI images of a sectioned liver tissue containing arterial vessels are converted into a finite element mesh. An rf heat source in the form of a spherically symmetric Gaussian distribution, fit from a previously computed profile, is employed Computations of temperature rise were performed for transient rf procedures in the case where the tumor is located near the bifurcation point of a hepatic artery. Results demonstrate a significant effect due to convective cooling by the large vessels. Substantial asymmetries in the temperature profiles indicate ablation procedures that may achieve adequate tumor destruction in some regions, but that elevate the temperature only minimally in other regions, thereby permitting possible tumor recursion. These critical features of the temperature field are due to the directional nature of the arterial flow and are difficult to capture with models that treat perfusion with a scalar source term in the bioheat equation.Copyright © 2003 by ASME