Conductivity Changes of Liver Tissue during Irreversible Electroporation and Calculation of the Electric Field Distribution

Aims: In irreversible electroporation process, the membrane of cancer cells is damaged irreversibly by electric pulses of high-intensity field, which in turn leads to cell death. Factors influencing the field distribution include voltage, pulse width, and electric conductivity of tissue. The present study was conducted with the aim of evaluating conductivity changes of liver tissue during irreversible electroporation and calculation of the electric field distribution. In the present experimental study, using simulation, the relationship between pulse width and voltage intensity of each pulse was investigated in conductivity changes during irreversible electroporation, and the electric field distribution was calculated. In this simulation, in order to solve the equations, the software COMSOL 5 was used. Needle electrodes were used, and the liver tissue was considered as the target tissue. Eight pulses with the stimulated frequency of 1Hz, pulse width of 100µs and 2ms, and the intensity of the electric fields ranging from 1000 to 3000v/cm were used as electric pulses. Findings: Conductivity of tissue increased during sending the electrical pulses. The conductivity changes in the tip of the electrodes were more than the area between the two rows of electrodes. As the intensity of the pulsed electric field increased, the tissue conductivity also increased. When the conductivity of the tissue was constant and variable, the maximum electric field intensity was obtained 3879 and 3448v/cm. While electric pulse transmission, tissue conductivity increases. The electric field distribution depends on the conductivity at the desired point and by changing this conductivity due to the electroporation, the electric field distribution also changes and the maximum intensity of the electric field decreases.