%0 Journal Article
%T Thermal modeling of lesion growth with radiofrequency ablation devices
%A Isaac A Chang
%A Uyen D Nguyen
%J BioMedical Engineering OnLine
%D 2004
%I BioMed Central
%R 10.1186/1475-925x-3-27
%X We present an axisymmetric two-dimensional finite element model that calculates cell damage in tissues and compare lesion sizes using common tissue damage and iso-temperature contour definitions. The model accounts for both temperature-dependent changes in the electrical conductivity of tissue as well as tissue damage-dependent changes in local tissue perfusion. The data is validated using excised porcine liver tissues.The data demonstrate the size of thermal lesions is grossly overestimated when calculated using traditional temperature isocontours of 42¡ãC and 47¡ãC. The computational model results predicted lesion dimensions that were within 5% of the experimental measurements.When modeling radiofrequency ablation problems, temperature isotherms may not be representative of actual tissue damage patterns.The mitigation of primary and metastatic tumors by radiofrequency ablation is a developing research area. The goal of ablation is to necrose treatment volumes by raising the temperature of targeted tissues. Ablation probes are inserted percutaneously, laparoscopically, or during surgery into cancerous tumors. Once positioned, high frequency alternating current (450¨C550 kHz) is delivered through an uninsulated electrode into the surrounding tissues to a dispersive ground pad that is applied to the patient. The electromagnetic energy is converted to heat by resistive heating.While the usage of radiofrequency ablation devices is well established, efforts to optimize treatment strategies are ongoing. An important consideration in optimizing ablation is determining what treatment volumes are necessary and acceptable. In liver ablation, for example, treatment volumes generally extend a centimeter beyond the dimensions of a tumor [1-3]. Since the liver possesses regenerative characteristics, it is more critical to insure that necrosis is achieved in 100% of the cancerous cell volume than to minimize damage to healthy tissues. In contrast, a centimeter margin in cardiac abla
%U http://www.biomedical-engineering-online.com/content/3/1/27