Experimental Characterization and Numerical Modeling of Tissue Electrical Conductivity during Pulsed Electric Fields for Irreversible Electroporation Treatment Planning

• Published in: IEEE transactions on biomedical engineering Vol. 59; no. 4; pp. 1076 - 1085
• Main Authors: Neal II, Robert E. , Garcia, Paulo A., Robertson, John L., Davalos, Rafael V.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.04.2012; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Animals; Bioimpedance; Biological and medical sciences; cancer therapy; Cell Membrane Permeability - physiology; Cell Membrane Permeability - radiation effects; Computer Simulation; Computerized, statistical medical data processing and models in biomedicine; Conductivity; Dose-Response Relationship, Radiation; Electric Conductivity; Electric fields; electrochemotherapy; Electromagnetic Fields; Electroporation - methods; Immune system; Kidney; Kidney - physiology; Kidney - radiation effects; Mathematical model; Medical sciences; Models and simulation; Models, Biological; nonthermal focal tumor ablation; Numerical models; Radiation Dosage; Studies; Swine; Tumors; Electrical conductivity; electrochemotherapy; Malignant tumor; Experimental study; Ablation; cancer therapy; Electric field; Treatment; Bioimpedance; Pulsed field; Numerical simulation; nonthermal focal tumor ablation; Treatment planning; Irreversible electroporation; Cancer; Biomedical engineering
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/TBME.2012.2182994

Irreversible electroporation is a new technique to kill cells in targeted tissue, such as tumors, through a nonthermal mechanism using electric pulses to irrecoverably disrupt the cell membrane. Treatment effects relate to the tissue electric field distribution, which can be predicted with numerical modeling for therapy planning. Pulse effects will change the cell and tissue properties through thermal and electroporation (EP)-based processes. This investigation characterizes these changes by measuring the electrical conductivity and temperature of ex vivo renal porcine tissue within a single pulse and for a 200 pulse protocol. These changes are incorporated into an equivalent circuit model for cells and tissue with a variable EP-based resistance, providing a potential method to estimate conductivity as a function of electric field and pulse length for other tissues. Finally, a numerical model using a human kidney volumetric mesh evaluated how treatment predictions vary when EP- and temperature-based electrical conductivity changes are incorporated. We conclude that significant changes in predicted outcomes will occur when the experimental results are applied to the numerical model, where the direction and degree of change varies with the electric field considered.