A Dual Slot Antenna with a Floating Metallic Sleeve for Microwave Ablave of Liver Tumour

Abstract

Background: Many antennas had been proposed to deliver localized electromagnetic wave to the tumour. Some of these antennas are not without shortcomings especially high power reflection coefficient, low power dissipation into the tissue, heat elongation on the antenna feedline, and excessive backward heating along the antennas shaft.

Objective: To design a new antenna with the intention to create large ablation volume, high aspect ratio and low backward heating for microwave ablation of tissues.

Materials and Methods: Finite Element Methods (FEM) in the COMSOL MULTIPHYSICS™ software was used to design and imulate antennas and to study the electromagnetic field and thermal distributions in the liver tissue. Two antennas were fabricated from coaxial cable and connected to solid state microwave generator operating at 2.45 GHz. The powers were set at 30, ,80, and 120 W at ablation durations of 120 and 300 s.

Results: The best optimized design produced reflection coefficient of-25.3 dB and aspect ratio of 0.81. About 29.5% backward heating reduction along antenna shaft was achieved during the simulation. In most cases there was no statistical difference between simulated and experimented results in aspect ratios, ablation diameters and ablation lengths of the designed antenna.

Conclusion: The experimental validation results established that inclusion of a floating metallic sleeve on dual slot antenna for MW ablation increased ablation diameter and aspect ratio as well as decreased backward heating