Purpose: To evaluate the electric field generated by customized alternating electric fields (AEF) transducers for small animal applications using finite element analysis.
Methods: A simplified rat head model comprised of scalp, skull, cerebrospinal fluid, and white matter was simulated in Ansys Electronics. A pair of transducers was placed on the lateral sides of the brain, which had a tumor composed of a necrotic core and tumor shell recapitulating characteristics of a human brain tumor. The baseline AEF transducers were made of a metal electrode surrounded by a high dielectric material (ε = 5000) to concentrate the field. Hydrogel was added to fill the air gap between the scalp and transducers to improve the field transmission. The customized transducers accommodated aluminum caps to increase the field strength and heat dissipation, titanium screws to stabilize the transducers on the rat head, and a thin layer of dental cement to seal the surgical areas. The induced voltage was set to 42 V at a frequency of 200 kHz.
Results: The electric fields generated by the customized AEF varied from 0.5-8.6 V/cm in the white matter; 1.5-5.1 V/cm in the tumor shell; and 0.5-4.6 V/cm in the tumor core. The average electric fields in the white matter, tumor shell, and tumor core were 1.49, 2.36, and 1.36 V/cm, respectively. The thermal load on the rat scalp was 6.3ᴼC. Compared to the baseline AEF, the results show that the customized setup increased the average field strength in the tumor shell by 28% while reducing the thermal load on the rat scalp by 8.5%.
Conclusion: The study strongly supports the idea of a dedicated AEF setup for small animal studies as a highly valuable addition to preclinical studies.
Funding Support, Disclosures, and Conflict of Interest: We are grateful to Ansys for their generous support. HN, YZ, CP, VAB, YN, VY, KES, and RWS have nothing to disclose financially. CBP and EC are co-inventors on patents US11103698B2 and US17/133,853. CBP received consulting fees from Novocure, Ltd, and receives research support from Novocure, Ltd. and Aveta Biomics.
Brain, Finite Element Analysis, Tumor Control