Optimal design of aperiodic tri-slot antennas for the conformal ablation of liver tumors using an experimentally validated MWA computer model

Objective: This study aims to demonstrate that the conformal microwave ablation (MWA) of liver tumors could be attained by optimizing the structure of an aperiodic tri-slot coaxial antenna, its insertion depth, and input power. Methods: A computational MWA model with an aperiodic tri-slot coaxial antenna operating at the frequency of 2.45 GHz was built and validated by both an ex vivo and a pilot in vivo experiment with porcine healthy livers. The validated in vivo computational MWA model implemented with a liver tumor was then used as a testbed to investigate the conformal ablation of liver tumors. Five liver tumors in different sizes and shapes were investigated. A genetic algorithm optimization method (NSGA-II) was used to optimize the structure of antenna, insertion depth of antenna, and microwave antenna input power for the conformal ablation of liver tumors. Results: The validation results showed that a good agreement in both the spatiotemporal temperature distribution and ablation zone was found between the computer model and the ex vivo experiments at both 45 W, 5 min and 60 W, 3 min treatments and the in vivo experiment at 45 W, 5 min treatment. The optimized simulation results confirmed that five cases of liver tumors in different sizes and shapes can be conformally ablated by optimizing the aperiodic tri-slot coaxial antenna, antenna insertion depth, and microwave antenna input power. Conclusion: This paper demonstrates that the aperiodic tri-slot coaxial antenna can be optimized with the insertion depth and input power for the conformal ablation of liver tumors, regardless the size and shape of liver tumors.

Automated summary

This study demonstrates the feasibility of conformal microwave ablation of liver tumors by optimizing the structure of an aperiodic tri-slot coaxial antenna, its insertion depth, and input power. The computational model and experiments validate the effectiveness of the optimized parameters in achieving conformal ablation of liver tumors, regardless of their size and shape.