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MS Defense Seminar

Robert B. Goergen Hall, Room 101

“Development of Crawling Wave Optical Coherence Elastography”

Presented by: Ying-Ju Chu

Co-advised by: Prof. Jannick Rolland and Prof. Kevin Parker

Over the past decades, the elastic property of biological tissues have been measured and mapped as a contrast mechanism in a variety of imaging techniques in order to provide quantitative means of tumor detection and other elasticity related diseases. The technique, assessing tissue composition and pathology on top of imaging, is known as elastography. Following up with the ultrasound imaging technique, optical coherence tomography started thriving as a key to explore a new elastographic scale in terms of resolution and the mechanical properties of tissue constituent level.

In this work, the development and implementation of shear wave excitation and data acquisition schemes as well as signal processing techniques for detection of slowly moving shear wave interference patterns, known as “crawling waves”, using Doppler optical coherence tomography, is reported.

To develop this technique, an optical coherence elastography (OCE) setup was conceived and implemented. Gelatin phantom were made with associated mechanical measurement of frequency dependent elasticity to serve as a comparison to the OCE measurements. Several different schemes, along with the simulation and measurement result are presented and discussed. In one implementation, the crawling wave was captured using OCE and results show good discrimination between 16% and 10% phantoms, motivating the advancement of the technique.