Optimization of electrode position in electric field treatment for pancreatic cancer.

BACKGROUND

In electric field-based cancer treatment, the intensity of the electric field applied to the tumor depends on the position of the electrode array, directly affecting the efficacy of treatment. The present study evaluated the effects of changing the position of the electrode array on the efficacy of electric field treatment for pancreatic cancer.

METHODS

A 3D model was created based on computed tomography images of 13 pancreatic cancer patients. An electrode array was placed on the surface of the model at various positions, and the electric field was calculated for each. Six treatment plans were created for each patient by rotating each electrode array ± 15⁰, ± 30⁰ in the axial plane, and ± 10⁰ in the sagittal plane relative to the reference plan. The frequency was set at 150 kHz and the current density at 31 mArms/cm for calculation of all treatment plans. The mean electric field, minimum electric field, homogeneity index (HI) and coverage index (CI) calculated from the six simulated plans were compared with the reference plan to evaluate the effects of each simulated plan on the tumor.

RESULTS

Comparisons of the simulated plans for each patient with the reference plan showed differences of -2.61 ∼ 11.31% in the mean electric field, -7.03 ∼ 13.87% in the minimum electric field, -64.14 ∼ 13.12% in the HI, and - 24.23 ∼ 11.00% in the CI. Compared with the reference plan, the optimal plans created by changing the electrode position improved the mean electric field 7.41%, the minimum electric field 7.20%, the HI 4.57%, and the CI 8.46%.

CONCLUSIONS

Use of a treatment planning system to determine the optimal placement of the electrode array based on the anatomical characteristics of each patient can improve the intensity of the electric field applied to the tumor.