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Caitlin Regan, Roche/ARCS Scholar, UCI School of Engineering

Posted on Wednesday, July 6, 2016

Caitlin graduated with Honors from the California Institute of Technology in 2012 with a B.S. in Bioengineering specializing in Mechanics.  She went on to receive her M.S. degree in Biomedical Engineering from the University of California, Irvine. She is continuing to pursue her PhD in Biomedical Engineering as a Biophotonics IGERT fellow working in the Microvascular Imaging Laboratory at Beckman Laser Institute under the guidance of Dr. Bernard Choi.

Caitlin’s research is focused around a technology called laser speckle imaging. This technique uses laser light to measure information about blood flow in tissues. When you shine a low-power laser (like a laser pointer) onto the skin, it forms a pattern of bright and dark spots we call “speckles” that look similar to TV static. These speckles fluctuate over time at a rate proportional to the speed of flowing red blood cells. Therefore, when we take a picture of this pattern it will appear blurry in areas where there is high blood flow; similar to taking a snapshot of a car speeding down the street. We perform some image processing in order to get images that map the perfusion in our tissue.

The main focus of Caitlin’s research is trying to improve the ability of this technique to image blood flow below structures that aren’t moving, such as the skin, the skull, and the teeth. Traditionally, the signal from these non-moving structures obscures the information about flow that researchers are interested in, and makes it difficult to get a clear image of blood vessels buried below them. Caitlin works on a mixture of experimental and computational techniques in order to try and improve this technology, as well as applying it to patients in the clinic to help monitor oral health.

One way she has been able to get clearer images of blood vessels under the skin is by shining a quick pulse of yellow laser light onto the sample. The blood absorbs the energy from this light, which causes it to get warmer and expand. This change in motion creates a stronger signal in the blood vessels as compared to the surrounding tissue, making it easier to resolve them in an image. She was able to travel to Sweden last summer to present this research and get feedback from colleagues around the world thanks to the generous contribution from the Roche/ARCS Foundation.

 Another project Caitlin has been working on for the last year is to use computer simulations to understand how light travels through different tissues. Using this model, she can predict the speckle contrast values for many different samples with different geometries and optical properties. She is using this model to help understand how deep within the skin we are measuring blood flow, and how different wavelengths of light may provide different information about the localization of the blood flow.

The last project Caitlin works on is a clinical study to apply laser speckle imaging towards measuring blood flow in the mouth. In particular, the study is to test a device to measure blood flow in the teeth in order to help inform a clinician whether or not a damaged tooth is viable, and if the patient needs a root canal.

When Caitlin is not in the lab, she spends her time playing water polo with the UCI club team and the Riptide Women’s Masters team, and enjoys other outdoor activities including running, hiking, biking and playing tennis.