"Can Integrated Photoacoustic/Ultrasonic Imaging Become the Preferred Modality for Molecular Imaging?"

Matthew O'Donnell, PhD - University of Washington

Faculty host:  Xiaoping Hu

Abstract:

Photoacoustics (PA) can be used to image the distribution of optical absorption in tissue, combining the specificity and sensitivity of optical imaging with the high resolution and penetration of ultrasound imaging. It represents one of the most promising techniques for molecular imaging because the optical absorption of bioconjugated nanoparticles can greatly exceed that of tissue over a range of wavelengths in which light can penetrate multiple centimeters into the body. We have explored several types of nanoparticles conjugated to a range of antibodies and aptamers targeted to several important biological systems. Here we discuss the general principles related to these contrast agents using a specific clinical problem: identifying inflamed endothelial cells signaling the early stages of atherosclerosis. 

In general, background signals from tissue can severely limit the specificity of all molecular imaging systems. This is especially problematic for PA detection of targeted cells circulating in the vasculature where the large PA signal from blood can completely mask the contrast agent signal. For sensitive detection of targeted cells in the vasculature, their

PA signal must be greatly enhanced compared to the blood background. In the 2nd half of this presentation we will discuss a new class of contrast agents called coupled particles that can substantially reduce artifacts due to background signals. We have developed technologies that can potentially accumulate and concentrate targeted cells such as metastatic cells while simultaneously enhancing their specific contrast compared to background signals.

The Bioengineering Seminar Series is a joint seminar series between IBB and the BME department. Seminars are held on Tuesdays or Thursdays between 11am-12pm in IBB room 1128 unless otherwise indicated.