Mitigation of impedance changes due to electroporation therapy using bursts of XXXX .

@entity415 @entity162
BACKGROUND: For electroporation-based therapies, accurate modeling of the electric field distribution within the target tissue is important for predicting the treatment volume. In response to conventional, unipolar pulses, the electrical impedance of a tissue varies as a function of the local electric field, leading to a redistribution of the field. These dynamic impedance changes, which depend on the tissue type and the applied electric field, need to be quantified a priori, making mathematical modeling complicated. Here, it is shown that the impedance changes during high-frequency, bipolar electroporation therapy are reduced, and the electric field distribution can be approximated using the analytical solution to Laplace's equation that is valid for a homogeneous medium of constant conductivity. METHODS: Two methods were used to examine the agreement between the analytical solution to Laplace's equation and the electric fields generated by 100   s unipolar pulses and bursts of 1   s @entity162 . First, pulses were applied to @entity415 tuber tissue while an infrared camera was used to monitor the temperature distribution in real-time as a corollary to the electric field distribution. The analytical solution was overlaid on the thermal images for a qualitative assessment of the electric fields. Second, @entity415 ablations were performed and the lesion size was measured along the x- and y-axes. These values were compared to the analytical solution to quantify its ability to predict treatment outcomes. To analyze the dynamic impedance changes due to electroporation at different frequencies, electrical impedance measurements (1 Hz to 1 MHz) were made before and after the treatment of @entity415 tissue. RESULTS: For high-frequency bipolar burst treatment, the thermal images closely mirrored the constant electric field contours. The @entity415 tissue lesions differed from the analytical solution by 39.7    1.3 % (x-axis) and 6.87    6.26 % (y-axis) for conventional unipolar pulses, and 15.46    1.37 % (x-axis) and 3.63    5.9 % (y-axis) for high- frequency @entity162 . CONCLUSIONS: The electric field distributions due to high-frequency, bipolar electroporation pulses can be closely approximated with the homogeneous analytical solution. This paves way for modeling fields without prior characterization of non-linear tissue properties, and thereby simplifying electroporation procedures.
