The use of microwaves for biomedical diagnostics and treatment has been a growing area of research within both the electromagnetics and healthcare communities. For example, microwave medical imaging, which in essence is a multistatic radar system, has been investigated for noninvasive and non-ionizing diagnostics. Radio frequency (RF) ablation has been used for treatment of malignant lesions. Microwave hyperthermia has been used for enhancing drug absorption and promoting healing processes. For delivering thermal therapies, a persistent challenge is monitoring the temporal and spatial progression of heat deposition to prevent under- or over-treatment. Given the strong dependence of the permittivity of both healthy and malignant biological tissue on temperature, in the past several years our team has been investigating the efficacy of microwave imaging for monitoring of thermal treatments, especially in near-real-time for intra-operative purposes. As such, by using progressively accelerated inverse scattering methods for estimating tissue dielectric constant, we are able to map the temperature of the 3D treatment domain in near-real time. This talk will provide an overview of our recent work on microwave inverse scattering systems for the purpose of providing rapid thermal monitoring. We will describe a number of developments that have resulted in more accurate, higher-resolution, and rapid image generation, including the simultaneous use of multiple frequencies, optimization of transmit-receive measurement pairs, and the use of a convolutional neural network trained with MRI images. A sampling of results will be presented to show successful retrieval of dielectric constant and temperature fields with a precision of 1° C and spatial resolution of sub-cm at a refresh rate of about 1 frame per second, which has the promise of making this technology realistically useful in a clinical setting.
Mahta Moghaddam is Distinguished Professor and Ming Hsieh Endowed Chair in Electrical and Computer Engineering at the Viterbi School of Engineering, University of Southern California (USC), Los Angeles, CA, USA. She currently serves as the Viterbi School Vice Dean for Research and Co-Chair of the USC President’s Working Group on Sustainability. She is also the Co-Director of the USC Center for Sustainability Solutions. Prior to USC she was at the University of Michigan (2003-2011) and NASA Jet Propulsion Laboratory (JPL, 1991-2003). She received the B.S. degree in 1986 from the University of Kansas, Lawrence, Kansas with highest distinction, and the M.S. and Ph.D. degrees in 1989 and 1991, respectively, from the University of Illinois at Urbana-Champaign, all in Electrical and Computer Engineering. Mahta’s expertise is in microwave sensing for environmental and biomedical applications. She was Systems Engineer for the Cassini Radar and served as Science Chair of the JPL Team X (Advanced Mission Studies Team). Her most recent research interests include the development of multistatic radar instrument and measurement technologies, including software-defined radar, for subsurface and subcanopy characterization, development of forward and inverse scattering techniques for layered random media especially for root-zone soil moisture, ground water, and permafrost applications, geophysical retrievals using signal-of-opportunity reflectometry, and transforming concepts of radar remote sensing to medical imaging and therapy systems. Mahta is a member of the Science Team of the Cyclones Global Navigation Satellite System (CYGNSS) mission, and the Arctic Boreal Vulnerability Experiment (ABoVE). She was the principal investigator of the AirMOSS NASA Earth Ventures 1 mission. She is a Fellow of IEEE and a member of the National Academy of Engineering.
Distinguished Professor and Ming Hsieh Endowed Chair in Electrical and Computer Engineering
Viterbi School of Engineering, University of Southern California (USC), Los Angeles, CA, USA