April 2015 BRIC Seminar Series Presentation

When Apr 08, 2015
from 12:00 PM to 01:00 PM
Where Marsico Hall, Room 4004
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A Contemporary Ceraunoscope: Using Photoacoustics to Probe Tissue Structure at Multiple Length Scales by Listening to 1 to 1000 MHz Ultrasound Waves 

Photoacoustic imaging is an emerging imaging modality that offers high sensitivity imaging (due to predominantly optical contrast) with ultrasonic resolution (due to 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 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 (including commercial ultrasound scanners). Using this methodology, spatial maps of optical absorption can be formed based on the reconstruction approach used. Due to the changes in optical absorption of oxygenated and deoxygenated blood, photoacoustic imaging can be used to generate oxygenation maps within tissue. Our recent work on analysis of the wideband photoacoustic signals from single red blood cells, single blood vessels and vascular trees will be presented. In particular 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.

This presentation will be held in 4004 Marsico Hall on Wednesday, March 11, 2015 from 12-1PM.