Methods of optimization of electrical impedance tomography for imaging tissue electroporation

Abstract

Tissue electroporation is a medical technique in which electrical pulses of microsecond to millisecond length are applied to a tissue in order to permeabilize the membrane of targeted cells, either temporarily or permanently, for the purpose of drug delivery and gene therapy or tissue ablation, respectively. Electrical impedance tomography (EIT) has been suggested as an effective means of imaging the treated area and thereby providing control of electroporation. In this simulation based study we introduce methods for optimizing the use of EIT under the special conditions of electroporation. First, we address the issue of the rapid changes in tissue conductivity, during and after the application of pulses. We propose a solution through a method of simultaneously collecting data from all the electrodes, essentially capturing the state of the tissue at a single instant. This method, which employs several distinct frequencies, one for each electrode, allows a speedy and continuous collection of data, a vital part of real-time electroporation monitoring. The second issue is taking advantage of the presence of electroporation electrodes for the EIT process. We show how the electroporation electrodes that are normally found inside the tissue may help improve the reconstruction compared to data collected only from the body's boundary. This mathematical study employs recently collected in vivo data of rat liver electroporation to obtain a model which represents, as closely as possible, the reality of electroporation procedures.