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Prof. Michael KoliosRyerson U.
Date of Live Presentation: tba
Photoacoustic imaging is an emerging imaging modality that offers high sensitivity imaging (driven by optical contrast) with ultrasonic resolution (driven by ultrasound detection). In photoacoustic imaging, the absorbed energy from a short electromagnetic pulse (typically laser light) causes localized heating. The resulting thermal expansion creates a pressure wave that can be then detected using conventional ultrasound technologies. The transient thermoelastic expansion of optically absorbing structures creates wideband acoustic emissions (including the ultrasonic range: from MHz to GHz) that can then be detected using existing ultrasound detection technologies. Using this methodology, spatial maps of optical absorption can be formed, and different reconstruction approaches can be used. Due to the changes in optical absorption of oxygenated and deoxygenated blood, photoacoustic imaging can be used to generate tissue oxygenation maps. An overview of the field will be presented, and our recent work on the analysis of the wideband photoacoustic signals from single red blood cells, single blood vessels, and vascular trees will be shown. We will show how analysis of the photoacoustic signals can be used to image and characterize vascular tissue from the mm scale (using MHz ultrasound detectors) to the micron scale (using GHz ultrasound detectors). Our recent efforts in combining conventional ultrasound tissue characterization techniques (using pulse-echo ultrasound), with photoacoustic tissue characterization techniques (applying similar signal analysis methodology on the co-registered photoacoustic signals) will be presented, with applications ranging from the characterization of blood and the imaging of cancer treatment response.
Dr. Kolios is a Professor in the Department of Physics at Ryerson University and Associate Dean of Research and Graduate Studies in the Faculty of Science. His work focuses on the use of ultrasound and optics in the biomedical sciences. His laboratory houses state-of-the-art ultrasound and photoacoustic tools using frequencies ranging from 1 to 1000 MHz to study the interaction of ultrasound and light with biological materials for imaging and therapy. Dr. Kolios leads a large group of projects that focus on optical and ultrasound methods used to characterize tissues and disease, as well as to develop theranostic agents that will assist in both therapeutic and diagnostic applications. To date, he has published over 100 peer-reviewed journal publications, 5 book chapters and 132 papers in conference proceedings. He has been invited to speak at many different organizations/conferences and has been the keynote and plenary speaker for conferences in Canada, India, and China. Dr. Kolios has received numerous teaching and research awards, including the Canada Research Chair in Biomedical Applications of Ultrasound, the Ontario Premiers Research Excellence Award, and the Ryerson Faculty Teaching Award. In 2016 received the American Institute of Ultrasound in Medicine (AIUM) Joseph H. Holmes Basic Science Pioneer