Thermo-elastic optical coherence microscopy

Aaron Doug Deen, Tom Pfeiffer, Heleen Van Beusekom, Jeroen Essers, Robert Huber, Antonius F.W. Van Der Steen, Gijs Van Soest, Tianshi Wang*

*Corresponding author for this work

Abstract

The absorption of laser pulses by tissue leads not only to the generation of acoustic waves, but also to nanometer to sub-micrometer scale displacement. After the initial expansion, a quasi-steady state is achieved in a few microseconds. Previously we introduced the concept of thermo-elastic optical coherence tomography (TE-OCT) to "visualise" the rapid thermo-elastic expansion by measuring the Doppler phase shift rather than istening" to the acoustic wave as in photoacoustic imaging. In this study, we built a microscopic setup for high-speed 3D TE-OCT imaging, by means of thermo-elastic optical coherence microscopy (TE-OCM). The repetition rate of pulsed laser was set to 100 Hz and the line rate of the OCT system is 1.5 MHz. The OCT beam and the laser pulse were focused upon the same location on the sample FWHM spot sizes of 300 μm for the pulsed laser and 40 μm FWHM for the OCT beam. For each laser pulse, an M-mode OCT image consisting of 90 A-lines was acquired. The Doppler phase shift was extracted by comparing the phase signal before and after the pulse arrival. Within 6 minutes, a 3D TE-OCM image (10 × 10 × 4 mm3) can be acquired and processed. Imaging experiments were carried out in swine meat using 1210 nm excitation wavelength to highlight lipid in tissue. The results show that no significant displacement was detected in swine muscle while strong displacement was observed in lipid, owing to the optical absorption features. Furthermore, fatty tissue is easily identified in the 3D TE-OCM image while the conventional OCT images provides the structural information.

Original languageEnglish
Title of host publicationAdvanced Chemical Microscopy for Life Science and Translational Medicine
EditorsJi-Xin Cheng, Wei Min, Garth J. Simpson
Number of pages6
PublisherSPIE
Publication date21.02.2020
Article number112520H
ISBN (Print)978-151063267-7
DOIs
Publication statusPublished - 21.02.2020
EventAdvanced Chemical Microscopy for Life Science and Translational Medicine 2020 - San Francisco, United States
Duration: 01.02.202003.02.2020
Conference number: 158693

Research Areas and Centers

  • Academic Focus: Biomedical Engineering

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