Abstract:
The present study aims at proposing a relationship between the coagulation volume and the
target tip temperature in different tissues (viz., liver, lung, kidney, and breast) during temperaturecontrolled
radiofrequency ablation (RFA). A 20-min RFA has been modelled using commercially
available monopolar multi-tine electrode subjected to different target tip temperatures that
varied from 70°C to 100°C with an increment of 10°C. A closed-loop feedback proportionalintegral-
derivative (PID) controller has been employed within the finite element model to perform
temperature-controlled RFA. The coagulation necrosis has been attained by solving the coupled
electric field distribution, the Pennes bioheat and the first-order Arrhenius rate equations within
the three-dimensional finite element model of different tissues. The computational study considers
temperature-dependent electrical and thermal conductivities along with the non-linear
piecewise model of blood perfusion. The comparison between coagulation volume obtained from
the numerical and in vitro experimental studies has been done to evaluate the aptness of the
numerical models. In the present study, a total of 20 numerical simulations have been performed
along with 12 experiments on tissue-mimicking phantom gel using RFA device. The study
revealed a strong dependence of the coagulation volume on the pre-set target tip temperature
and ablation time during RFA application. Further, the effect of target tip temperature on the
applied input voltage has been studied in different tissues. Based on the results attained from the
numerical study, statistical correlations between the coagulation volume and treatment time have
been developed at different target tip temperatures for each tissue.
