title: Simulation of temperature field for temperature-controlled radio frequency ablation using a hyperbolic bioheat equation and temperature-varied voltage calibration: a liver-mimicking phantom study.
abstract: This study aims at improving the accuracy of temperature simulation for temperature-controlled radio frequency ablation (RFA). We proposed a new voltage-calibration method in the simulation and investigated the feasibility of a hyperbolic bioheat equation (HBE) in the RFA simulation with longer durations and higher power. A total of 40 RFA experiments was conducted in a liver-mimicking phantom. Four mathematical models with multipolar electrodes were developed by the finite element method in COMSOL software: HBE with/without voltage calibration, and the Pennes bioheat equation (PBE) with/without voltage calibration. The temperature-varied voltage calibration used in the simulation was calculated from an experimental power output and temperature-dependent resistance of liver tissue. We employed the HBE in simulation by considering the delay time τ of 16 s. First, for simulations by each kind of bioheat equation (PBE or HBE), we compared the differences between the temperature-varied voltage-calibration and the fixed-voltage values used in the simulations. Then, the comparisons were conducted between the PBE and the HBE in the simulations with temperature-varied voltage calibration. We verified the simulation results by experimental temperature measurements on nine specific points of the tissue phantom. The results showed that: (1) the proposed voltage-calibration method improved the simulation accuracy of temperature-controlled RFA for both the PBE and the HBE, and (2) for temperature-controlled RFA simulation with the temperature-varied voltage calibration, the HBE method was 0.55 °C more accurate than the PBE method. The proposed temperature-varied voltage calibration may be useful in temperature field simulations of temperature-controlled RFA. Besides, the HBE may be used as an alternative in the simulation of long-duration high-power RFA.
authors.affiliation: College of Life Science and Bioengineering, Beijing University of Technology, Beijing, People's Republic of China.
authors.forename: Man
authors.initials: M
authors.lastname: Zhang
authors.forename: Zhuhuang
authors.initials: Z
authors.lastname: Zhou
authors.forename: Shuicai
authors.initials: S
authors.lastname: Wu
authors.forename: Lan
authors.initials: L
authors.lastname: Lin
authors.forename: Hongjian
authors.initials: H
authors.lastname: Gao
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Feng
mesh_terms: D001831:Body Temperature / Q000502:physiology*; D002138:Calibration; D017115:Catheter Ablation / Q000379:methods*; D003198:Computer Simulation; D004566:Electrodes; D006801:Humans; D008099:Liver / Q000502:physiology* / Q000601:surgery*; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D012984:Software