Coaxial Slot Antenna for Microwave Ablation in Breast Tissue: A Simplistic Axisymmetric Finite Element Method Model Employing State-of-the-Art Advanced Multiphysics Simulation Software
DOI: 10.65220/v7m4x9
Authors: Mario Francisco Jesús Cepeda Rubio*, Francisco Gerardo Flores García, José Irving Hernández Jacquez, Mario Candelario Cepeda Medina, Geshel David Guerrero López, Kristian Segura Félix, Abril Cepeda Rubio, Arturo Vera Hernández, Lorenzo Leija Salas
Affiliations: 1) Tecnológico Nacional de México / Instituto Tecnológico de La Laguna, Torreón, Coahuila, Mexico · 2) CBTIS 196, Matamoros, Coahuila, Mexico · 3) Universidad Tecnológica de Torreón, Coahuila, Mexico · 4) Universidad Autónoma de La Laguna, Torreón, Coahuila, Mexico · 5) CINVESTAV-IPN, Mexico City, Mexico
Received: 1 September 2023 · Accepted: 2 October 2023 · Published: 17 October 2023
Open Access: CC BY 4.0 (post–peer review & technical editing).
Peer Review: Double-blind; at least two independent reviewers.
Abstract
Microwave energy holds significant potential for medical applications, especially in treating breast carcinomas. Its effectiveness lies in its ability to selectively target and heat tissues with high water content, such as cancerous cells, while causing minimal heating in lower-water-content tissues like adipose and glandular tissues in the breast. This study employs the latest version of COMSOL Multiphysics to revalidate earlier axisymmetric models and examine computational consistency. Practical ablation experiments on ex vivo swine tissue complemented the simulations, reinforcing the reliability of computational modeling and antenna design for clinical use.
Keywords: Microwave ablation, high-water-content tissues, adipose and glandular tissues, breast cancer, finite element model, COMSOL Multiphysics.
Introduction
Microwave ablation (MWA) uses localized heating to induce tumor necrosis, providing selective heating for breast carcinomas with high water content. Its efficiency depends on the dielectric and thermal properties of the tissue, the applied power, and treatment duration. This work updates earlier computational research to confirm reproducibility and accuracy with modern software.
Computer Modeling
Based on earlier studies using COMSOL Multiphysics 3.5a, this paper presents an updated simulation using COMSOL 6.1. The antenna operates at 2.45 GHz and was modeled as axisymmetric to simplify calculations. Perfect electric conductor (PEC) boundaries simulated the antenna surfaces, while absorbing conditions minimized reflections. Results confirmed stable electromagnetic and thermal responses, validating the fidelity of updated modeling environments.
Antenna Design
The antenna was constructed from a 50 Ω UT-085 semirigid coaxial cable with an SMB connector. Its copper outer conductor features a 1 mm-wide ring slot near the short-circuited tip to propagate microwave energy efficiently. The inner conductor is silver-plated copper (SPCW) with a PTFE dielectric, wrapped in Teflon to prevent adhesion to desiccated tissue post-ablation.
Experimental Validation
Before ablation, dielectric properties of adipose-dominated breast tissue were measured at 2.45 GHz using a precision coaxial probe and a network analyzer. The coaxial antenna was inserted into homogeneous swine breast tissue and energized at 10 W for 3 minutes. The experimental setup confirmed that MWA preferentially heats cancerous-like regions due to distinct dielectric properties.
Results and Discussion
The computational and experimental results demonstrated negligible differences between COMSOL versions. Both simulation and physical validation confirmed focused energy deposition and selective tumor heating. These findings reinforce the robustness of the antenna design and its reproducibility across modeling platforms.
Conclusion
The updated computational modeling and experimental validation confirm the reliability of the coaxial slot antenna design for safe and effective microwave ablation in breast tissue. The model demonstrates high reproducibility and strong potential for clinical translation in oncological treatment.
References
- S. García-Jimeno, R. Ortega-Palacios, M. Cepeda-Rubio, A. Vera, L. Leija, and J. Estelrich. Improved Thermal Ablation Efficacy Using Magnetic Nanoparticles: A Study in Tumor Phantoms. Progress in Electromagnetics Research. 2012; 128: 229–248.
- M. F. J. Cepeda Rubio, A. Vera Hernández, L. Leija Salas, E. Ávila-Navarro, and E. A. Navarro. Coaxial Slot Antenna Design for Microwave Hyperthermia Using Finite-Difference Time-Domain and Finite Element Method. The Open Nanomedicine Journal. 2011; 3: 2–9.
- M. F. J. Cepeda, A. Vera and L. Leija. Coaxial Antenna for Microwave Coagulation Therapy in Ex Vivo Swine Breast Tissue. IEEE ICEEE. 2010: 268–273. doi:10.1109/ICEEE.2010.5608623.
- G. D. Guerrero López, M. F. J. Cepeda Rubio, J. I. Hernández Jácquez, A. Vera Hernández, L. Leija Salas, F. Valdés Perezgasga, F. Flores García. Computational FEM Model and Ex Vivo Validation of an Optimized Double-Slot Microcoaxial Antenna. Computational and Mathematical Methods in Medicine. 2017; 2017:1562869. doi:10.1155/2017/1562869.
- K. Segura Félix, G. D. Guerrero López, M. F. J. Cepeda Rubio, J. I. Hernández Jacquez, F. G. Flores García, A. V. Hernández, L. L. Salas, E. C. Orozco Ruiz de la Peña. Computational FEM Model and Phantom Validation of Microwave Ablation for Segmental Microcalcifications in Breasts Using a Coaxial Double-Slot Antenna. Biomed Res Int. 2021; 2021:8858822. doi:10.1155/2021/8858822.
© 2023 International Journal of Bioelectronics (IJBIOE). Article licensed under CC BY 4.0.
