Electrical field analysis of pentagonal needle array electrode for electrochemotherapy applications

Electrochemotherapy is an effective palliative way of treating inoperable chemo-resistant cancers. It is a therapeutic technique for treating tumors with nonpermeant drugs using electroporation of cells. The cells are electroporated to form temporary hydrophilic pores. The various parameters which affect the electroporation efficacy are, the voltage (electric field intensity), pulse length, number of pulses, pulse interval and the electrode. The electrode provides a contact between the high voltage pulse generator and the patient, and as such it plays a vital role in the treatment outcome. In general, needle array electrodes are used in many cases, including treating of deep seated tumors. The electric field distribution varies according to the electrode design. This paper explores the effectiveness of a pentagonal array electrode with a centre electrode for obtaining uniform electric field distribution in the treated area. This model is symmetrical in which surrounding electrodes are displaced by 4 mm from the centre electrode. The diameter of the needle is 1 mm. The electric field simulations were implemented in 2D in ANSYS 13.0. The electric field considered for the analysis is 1200 V/cm, same as what is currently used in the clinics. The results indicate that the electric field distribution is uniform at a value of 1200 V/cm.