112 research outputs found
A Simple Quantitative Inversion Approach for Microwave Imaging in Embedded Systems
No full textIn many applications of microwave imaging, there is the need of confining the device in order to shield it from environmental noise as well as to host the targets and the medium used for impedance matching purposes. For instance, in MWI for biomedical diagnostics a coupling medium is typically adopted to improve the penetration of the probing wave into the tissues. From the point of view of quantitative imaging procedures, that is aimed at retrieving the values of the complex permittivity in the domain under test, the presence of a confining structure entails an increase of complexity of the underlying modelling. This entails a further difficulty in achieving real-time imaging results, which are obviously of interest in practice. To address this challenge, we propose the application of a recently proposed inversion method that, making use of a suitable preprocessing of the data and a scenario-oriented field approximation, allows obtaining quantitative imaging results by means of quasi-real-time linear inversion, in a range of cases which is much broader than usual linearized approximations. The assessment of the method is carried out in the scalar 2D configuration and taking into account enclosures of different shapes and, to show the method's flexibility different shapes, embedding nonweak targets
Women Radio Science Contributions: A Special Greeting to Pat Doherty [Women in Engineering]
No full textTowards a low-complexity microwave imaging strategy for liver ablation monitoring
No full textThermal ablation represents an innovative treatment strategy for liver cancer therapy, having tangible advantages with respect to surgery. However, the main shortcoming, particularly crucial for microwave thermal ablation, is the necessity of monitoring in real time the treated region, so to provide information on the effectiveness of the treatment. Microwave imaging has been recently proposed as an effective tool for this goal, as it is capable of imaging the dielectric properties variations of liver tissues undergoing the ablation therapy. First investigations on simulated and experimental data corroborated the expected potentials. In this communication, a novel imaging approach able to work with a simplified measurement set-up is presented. The system simplification consists in a reduction of the number of antennas and in a measurement protocol which does not require any movement of the antenna array nor of the target under test. Preliminary results on experimental data are reported
An experimental assessment of thermal ablation monitoring via microwave tomography
No full textThis communication reports a first experimental assessment of the use of microwave tomography for monitoring thermal ablation for cancer treatments. In particular, the monitoring of a controlled microwave thermal ablation experiment on ex-vivo bovine liver sample is presented. The results confirm the capability of microwave tomography of providing information on the performed treatmen
Monitoring thermal ablation via microwave tomography. An ex vivo experimental assessment
No full textThermal ablation treatments are gaining a lot of attention in the clinics thanks to their reduced invasiveness and their capability of treating non-surgical patients. The effectiveness of these treatments and their impact in the hospital's routine would significantly increase if paired with a monitoring technique able to control the evolution of the treated area in real-time. This is particularly relevant in microwave thermal ablation, wherein the capability of treating larger tumors in a shorter time needs proper monitoring. Current diagnostic imaging techniques do not provide effective solutions to this issue for a number of reasons, including economical sustainability and safety. Hence, the development of alternative modalities is of interest. Microwave tomography, which aims at imaging the electromagnetic properties of a target under test, has been recently proposed for this scope, given the significant temperature-dependent changes of the dielectric properties of human tissues induced by thermal ablation. In this paper, the outcomes of the first ex vivo experimental study, performed to assess the expected potentialities of microwave tomography, are presented. The paper describes the validation study dealing with the imaging of the changes occurring in thermal ablation treatments. The experimental test was carried out on two ex vivo bovine liver samples and the reported results show the capability of microwave tomography of imaging the transition between ablated and untreated tissue. Moreover, the discussion section provides some guidelines to follow in order to improve the achievable performances
Women's Contributions in Electromagnetic Inverse Problems [Women in Engineering]
No full textScience is often considered a male-dominated field. Today, women are still discouraged from entering the fields of technology, engineering, and math and, in the last two years, the COVID-19 pandemic has worsened this situation. Nevertheless, despite challenges of gender discrimination and lack of recognition in the scientific community, countless inspiring women in these fields have made historic contributions to science and helped develop a better understanding of the world around us. Many women were not recognized in their own lifetimes, but their achievements have helped generations of female scientists to come
Monitoring Thermal Ablation Treatments Using Microwave Tomography
No full textReal-time monitoring of thermal ablation treatments by means of safe and low-cost imaging tools is a still unmet clinical need. Since ablation significantly changes the electromagnetic properties of tissue, microwave tomography is a potential candidate to fill this gap. In this communication, initial results from feasibility studies that corroborate such an expectation are reviewed and discusse
Design and Numerical Characterization of a Low-Complexity Microwave Device for Brain Stroke Monitoring
No full textThis paper presents the design of a novel low-complexity microwave imaging system for monitoring brain stroke. In particular, the design is concerned with the determination of the optimal layout of the antennas array, namely, minimum number, positions, and polarization of the radiating elements, enabling the acquisition of an amount of data such to assure a reliable imaging. This goal is achieved by adopting a rigorous design procedure based on the inspection of the singular value decomposition of the relevant discretized scattering operator and taking into account the actual dynamics and signal-to-noise ratio of the measurement system. The design is first carried out in the case of ideal dipoles and then extended and assessed for actual printed monopole antennas, developed for the imaging system. The resulting system is a helmet equipped with 24 antennas, whose performances have been numerically validated in terms of both spatial resolution and reconstruction capabilities, by employing full-wave numerical simulations, realistic 3-D phantoms of the human head, and an accurate modeling of the actual antennas employed in the system
Microwave imaging for liver thermal ablation monitoring. Developing an experimental set-up
No full textThermal ablation has been recognized as an effective method for liver malignancy treatment. The clinical difficulties lie in monitoring the treatment process in realtime. In recent years, microwave imaging has been proposed as a modality with out-standing features such as non-ionizing nature, cost-effective, and capable of realtime monitoring. In this respect, in this contribution, a low-complexity experimental set-up for the experimental assessment of microwave imaging system for liver ablation monitoring is proposed and numerically assessed. The reconstruction of images inside the liver shows that it is possible to localize the ablation zone in the abdomen phantom during the thermal ablation treatment. The results of this study lay the foundations for the experimental assessment of microwave imaging systems for thermal ablation monitoring
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