Microwave ablation (MWA) is a minimally invasive technique increasingly used for thermal therapy of liver tumors. Effective MWA requires efficient interstitial antennas that destroy tumors and a margin of healthy tissue, in situ, while minimizing damage to the rest of the organ. Previously, we presented a method for optimizing MWA antenna designs by coupling finite element method models of antennas with a real-coded, multiobjective genetic algorithm. We utilized this procedure to optimize the design of a minimally invasive choke antenna that can be used to create near-spherical ablation zones of adjustable size (radius 1-2 cm) by adjusting treatment durations and a sliding structure of the antenna. Computational results were validated with experiments in ex vivo bovine liver. The optimization procedure yielded antennas with reflection coefficients below -30 dB, which were capable of creating spherical ablation zones up to 2 cm in radius using 100 W input power at 2.45 GHz with treatment durations under 2 min.
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http://dx.doi.org/10.1109/TBME.2009.2025264 | DOI Listing |
Electromagn Biol Med
October 2024
Department of Engineering Design, Indian Institute of Technology Madras, Chennai, India.
Microwave applicators reported for intracavitary hyperthermia (HT) operate at single frequency and deliver fixed treatment coverage at the tumor target. In this work, we report multifrequency operation of a water-cooled monopole antenna with a sliding broadband ferrite choke for delivering intracavitary HT to the cervix with variable spatial coverage. Spatially varying treatment coverage is achieved by varying the choke position with respect to the monopole using a mechanical sliding arrangement and exciting the antenna at the modified resonant frequency.
View Article and Find Full Text PDFIn this reported work a single feed, miniaturized, dual layer, and low profile antenna is presented for 1.575GHz frequency band. The proposed antenna offers high gain, lower noise bandwidth, with better sensitivity and range.
View Article and Find Full Text PDFSci Rep
December 2023
Escuela de Ingeniería Eléctrica, Pontificia Universidad Católica de Valparaíso, 2340000, Valparaiso, Chile.
In this work, a fully 3D-printed choke corrugated Gaussian profile horn antenna (GPHA) using high-conductive filaments and a low-cost modular 3D-printing technique is implemented. The choke corrugated GPHA operates in the Ka-band, with a central frequency of 28 GHz. Although the antenna can be printed in one piece as its dimensions are within the printing limits, four pieces compose the three sections of the final 3D-printed antenna.
View Article and Find Full Text PDFSensors (Basel)
December 2023
Communications Research Group, Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Steet, Sheffield S1 3JD, UK.
A singly fed reconfigurable circular loop antenna is proposed for millimeter-wave (mmWave) communication systems. This antenna's distinctive feature lies in its capacity to adjust both polarization and bandwidth characteristics, a capability made possible by the strategic integration of two PIN diodes. These diodes are engineered to function in various modes, allowing for three distinct polarization states and accommodating two distinct bandwidths.
View Article and Find Full Text PDFCardiovasc Intervent Radiol
August 2023
Department of Interventional Radiology, Gustave Roussy, 114 Rue Edouard Vaillant, 94805, Villejuif, France.
Introduction: The safety and efficacy of a microwave ablation (MWA) system for the liver with novel technologies in field control, antenna cooling through the inner part of the choke ring, and dual temperature monitoring were evaluated in this multicenter retrospective study.
Material And Methods: Ablation characteristics and efficacy were assessed on follow-up imaging (computed tomography or magnetic resonance imaging). Safety was evaluated according to CTCAE classification.
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