Tissue Electroporation Modeling Research

Background Introduction

Electroporation is a phenomenon that occurs when cell membranes are exposed to short electrical pulses, increasing the permeability of the cell membrane to ions and macromolecules. Depending on the impact of electrical pulses on the cell membrane, electroporation can be classified as Reversible Electroporation (RE) or Irreversible Electroporation (IRE). IRE is a non-thermal tissue ablation technique that induces apoptosis by applying high-voltage pulses through electrodes, widely used in tumor treatment. However, traditional IRE simulation models fail to fully account for the effects of changes in electric field direction between pulses and increased conductivity in IRE regions on ablation outcomes. To address this issue, researchers proposed an improved numerical model aimed at more accurately predicting tumor ablation areas, enhancing the precision of clinical treatment planning.

Paper Source

This paper was jointly completed by Fei Guo, Xinghe Gou, and Cong Zou, all from the Institute of Ecological Safety at Chongqing University of Posts and Telecommunications. The paper was published in IEEE Transactions on Biomedical Engineering (TBME) and officially released in 2025. This research was partially supported by the National Natural Science Foundation of China (Grant No.: 52377223).

Research Process and Results

Research Process

1. Model Establishment and Parameter Setting
   The research team used finite element analysis software COMSOL Multiphysics 6.1 to construct a two-dimensional tumor model. The tumor was modeled as a circle with a radius of 1 cm, and the electrodes were made of stainless steel with a radius of 0.25 mm. Three electrodes were evenly distributed along a circle with a radius of 0.5 cm. Pulse parameters were set as follows: unipolar pulse width of 1 microsecond, amplitude of 2500 volts, with both rising and falling edges at 10 nanoseconds.

2. Electroporation Effect and Thermal Effect Simulation
   In the tumor model, researchers applied pulsed electric fields through electrodes, using Laplace’s equation to calculate the electric field distribution and the biological heat transfer equation to describe tissue temperature distribution. Conductivity modeling employed a smooth step function (Heaviside Function), considering the influence of electric field strength, temperature, and electroporation threshold.

3. Electric Field Direction Change Effect
   Researchers established, for the first time, a linear relationship between the angle of electric field direction change and the IRE threshold, incorporating it into the model. The angle of electric field direction change was calculated using the atan2 function, adjusting the IRE threshold to simulate the effect of electric field direction changes on ablation outcomes.

4. Increased Conductivity in IRE Regions
   Researchers improved the conductivity model to consider the increase in conductivity in IRE regions during subsequent pulse applications. In IRE regions, conductivity increases and does not return to its initial value, thereby affecting the electric field distribution in subsequent pulses.

5. Sobol Sensitivity Analysis
   To quantify the impact of parameter uncertainty on the ablation area, researchers used the Sobol method to analyze the sensitivity of four parameters (unipolar pulse IRE threshold, bipolar pulse IRE threshold, initial conductivity, and conductivity growth factor) on the ablation area.

Main Results

1. Electric Field and Conductivity Distribution
   Compared to traditional models, the improved model (Base_TI) showed a slight increase in the electric field in regions where the electric field direction changed but a significant decrease in the IRE regions. The conductivity distribution also changed due to the increased conductivity in IRE regions.

2. Ablation Area Changes
   The improved model significantly reduced the IRE and electroporation areas. Compared to the traditional model, the IRE area in the Base_TI model decreased by 14.40%, and the electroporation area decreased by 9.18%.

3. Sensitivity Analysis
   Sobol analysis indicated that the ablation area was primarily influenced by the unipolar and bipolar pulse IRE thresholds, with minimal impact from conductivity parameters.

4. Experimental Validation
   The predictive accuracy of the model was validated through potato slice experiments. Experimental results were highly consistent with the predictions of the improved model, confirming its validity.

Conclusion

The improved model proposed in this study incorporates, for the first time, changes in electric field direction and increased conductivity in IRE regions into tissue IRE ablation simulations, significantly improving the prediction accuracy of ablation areas. The results show that changes in electric field direction and increased conductivity in IRE regions have significant effects on electric field distribution, conductivity distribution, and ablation areas. The improved model provides more reliable theoretical support for clinical tumor treatment planning.

Research Highlights

1. Innovative Model
   For the first time, changes in electric field direction and increased conductivity in IRE regions were incorporated into IRE ablation simulations, addressing the shortcomings of traditional models.

2. High Prediction Accuracy
   The improved model significantly enhances the prediction accuracy of ablation areas, providing a more reliable basis for clinical treatments.

3. Experimental Validation
   The validity of the model was verified through potato slice experiments, enhancing the credibility of the research results.

Other Valuable Information

The study also pointed out that future research could consider incorporating pulse sequences and multi-pulse effects into the model to further optimize the prediction of tumor ablation outcomes.

---

This research provides important theoretical support for the clinical application of IRE technology, holding significant scientific value and practical application significance. By improving the model, researchers have opened new avenues for the precise formulation of tumor treatment plans.