5
Optical Coherence Tomography: Technical Aspect
Hrebesh M. Subhash
Division of Biomedical Engineering, School of Medicine, Oregon Health and Science University,
3303 SW Bond Ave, Portland, OR
Ruikang K. Wang
Biophotonics and Imaging Laboratory, Department of Bioengineering, University of Washington,
Seattle, WA
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
5.2 Low Coherence Interferometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
5.3 OCT Principle of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
5.4 Practical Aspect of OCT System Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
5.5 Different OCT Detection Schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
5.6 Functional OCT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
5.7 Applications and New Trends in OCT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
5.8 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
This chapter describes the s tate of the art of optical coherence tomography (OCT), a low coherence
interferometric imaging technique that provides cross-sectional depth resolved information from the
subsurface microstructure of biological tissue. Following a discussion of the basic theory of OCT,
an overview of the design aspect and different configuration of OCT in both time and frequency do-
main is presented. The chapter also includes various functional extensions of OCT and its potential
clinical and non-clinical application.
Key words: imaging, interferometry, optical coherence tomography, biomedical imaging, func-
tional imaging
5.1 Introduction
Optical coherence tomography (OCT) is a novel, non-invasive, optical imaging modality based
on low coherence interferometry. It was first conceived in 1990 by Dr. Naohiro Tanno, a professor at
Yamagata University [1, 2], and then perfected in 1991 by a Massachusetts Institute of Technology
team headed by Prof. James Fujimoto [3]. OCT enables the non-invasive, non-contact imaging
of cross-sectional structures in biological tissues and materials with high resolution. In principle,
OCT is an optical analogue to clinical ultrasound. In OCT, the temporally gated optical pulse
remitted from scattering sites within the sample is localized by low-coherence interferometry (LCI)
167

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