Computational And Experimental Study Of IRE Enhanced By RFA Using An In Vitro 3D HepG2 Cell Model

Irreversible electroporation(IRE)is a new powerful tool for tumor ablation,which utilizes electric pulses delivered by electrodes to a targeted area of tissue to produce pulsed electric fields,thus causing irreversible hydrophilic pores on the cell membrane.Compared with traditional cancer treatments,the boundary of IRE ablation zone is clearer,and there is less damage to the normal tissue around the tumor.However,the main disadvantage of IRE is incomplete ablation of large tumors leading to the recurrence of cancer.Radiofrequency ablation(RFA)is a thermal ablation technology,which utilizes high frequency alternating current to induce high frequency movement of ions in the tissue,and causes coagulation necrosis through friction heat.In order to solve the current problem of IRE,in this thesis,HepG2 cells were taken as the object to explore the enhancement of RFA preheating on the efficacy of IRE through experiments,and the enhancement mechanism was analyzed by combining with the computational model.The main work of this thesis are as follows:(1)The combined ablation experiments of RFA and then IRE were carried out on the in vitro 3D HepG2 cell models.(2)A heating and electrical conductivity measurement system was established to determine the function between conductivity of the 3D HepG2 cell models and temperature.(3)The computational models of RFA preheating and IRE ablation were established,and the above function was input into the models.(4)By comparing the computational models with the experimental results,the enhancement mechanism of the effect of RFA preheating on IRE was analyzed.The conclusions are as follows:(1)The ablation zones of RFA combined with IRE are larger than that of IRE alone,which proves that RFA preheating can enhance the efficacy of IRE.(2)The temperature change of the RFA simulation model is more correct through the conductivity-temperature function measured in the experiments;(3)By comparing the simulation model with the experimental results,it is concluded that RFA preheating can improve the electric conductivity of tissues,increase the current density in tissues and reduce the IRE lethal electric field threshold for HepG2 cells.