Abstract:
Imaging of the human body using microwaves had been a goal for many decades. The reasons are obvious. In comparison to X-rays, microwaves are non-ionizing and use relatively inexpensive components. The challenges, however, can be summarized in two fold: Microwaves do not travel in straight lines (or ray-like) as X-rays and therefore cannot be used in computed tomography modalities, and secondly, it had been commonly accepted in the published literature that material resolution is constrained by the Abe diffraction limit, which implies that higher imaging resolution requires higher frequency. These perceived key challenges led the imaging community to focus on inverse scattering algorithms. These imaging algorithms, which attempt to reconstruct the material properties of the object, lack mathematical robustness and rigor (i.e., they are ill-posed) and require complex setup and realization. In this seminar, we present a new modality for body imaging with specific focus on breast cancer detection. This modality is analogous to how X-ray imaging works, however, using low frequency instead of X-rays. At first, this seems highly counterintuitive as the prevalent understanding dictates that low frequencies would significantly compromise material resolution. The physics-based finding that will be discussed in this seminar shows the contrary. To complement this critical finding in achieving an imaging modality fully analogous to X-ray imaging, an electronic film, or a metasurface is used to capture an impression of the object (or the breast in the case of mammography) when illuminated by a low-power non-ionizing low frequency electromagnetic source. The metasurface absorbs the transmitted electromagnetic energy through the object or breast. An impression correlated to the composition of the breast is reconstructed by recording the microwave’s power absorbed by the metasurface. The advantages of this new imaging modality are that it provides benign non-invasive breast screening at a cost significantly lower than traditional screening modalities such as CT scan, MRI and X-ray mammography.
Speaker:
Dr. Omar Ramahi, Department of Electrical and Computer Engineering, University of Waterloo
Omar M. Ramahi (Fellow, IEEE) was born in Jerusalem, Palestine. He received the B.S. degrees (Highest Hons.) in mathematics and electrical and computer engineering from Oregon State University, Corvallis, Oregon, USA, in 1984, and the MS and Ph.D. degrees in electrical and computer engineering from the University of Illinois at Urbana–Champaign, Illinois, USA, in 1986 and 1990. He was with Digital Equipment Corporation (presently HP), MA, USA, where he was a member of the Alpha Server Product Development Group. In 2000, he joined the Faculty of the James Clark School of Engineering, the University of Maryland at College Park, MD, USA, as an Assistant Professor and later as a tenured Associate Professor, where he was also a Faculty Member of the CALCE Electronic Products and Systems Center. He is currently a Professor with the Department of Electrical and Computer Engineering, University of Waterloo, ON, Canada. He has authored and coauthored over 600 journal and conference technical articles on topics related to electromagnetic phenomena and computational techniques. He has coauthored the book EMI/EMC Computational Modeling Handbook (first edition: Kluwer, 1998, Second Ed: Springer-Verlag, 2001. Japanese edition published in 2005). Prof. Ramahi received the 2004 University of Maryland Pi Tau Sigma Purple Cam Shaft Award. He received the Excellent Paper Award from the 2004 International Symposium on Electromagnetic Compatibility, Sendai, Japan, and the 2010 University of Waterloo Award for Excellence in Graduate Supervision. In 2012, he was a recipient of the IEEE EMC Society Technical Achievement Award. In 2022, Professor Ramahi was the recipient of the 2022 University of Waterloo Engineering Research Excellence Award.