Analysis And Experiments On Lesion Size Of Hepatic Radiofrequency Ablation With Internally Cooled Probes

Radiofrequency Ablation (RFA) is a new minimally invasive method for physical treatment of tumors, which has been widely used in primary and matastatic liver cancer therapy. It is known by its secure, simple, effective and low surgical risk. With academic analysis and experimental research, we evaluated the lesion size under different therapeutic parameters, based on the internally cooled radiofrequency ablation system developed by our institute. This paper established the therapeutic parameters of the system, and gave guidance on clinical application.The first part of this paper is to analyze the lesion size, used finite element methods. Heat transfer in tissue is governed by bio-heat transfer equation. We set finite element models for the process of radiofrequency ablation. Based on the constant tissue parameter model, we put forward a temperature dependent conductivity finite element model, and compared with each other. Through thermal-electrical coupled field analysis, we can calculate electric field,temperature distributions of the two models, during the radiofrequency ablation process. And get the critical temperature (50℃) lesion size. Analytical results showed, under the same volts and time, tissue temperature of temperature dependent conductivity model raised more quickly, over 140V may cause vaporization where gas forms and creates an electrically insulating layer, which should be avoided in clinical use.