High-speed optical coherence tomography: basics and applications
Published in Applied Optics, Vol. 49 Issue 16, pp.D30-D61 (2010)
Spotlight summary: The introduction of Fourier-domain (Fd) detection to optical coherence tomography (OCT), just over a decade ago, revolutionized the field of imaging by drastically increasing acquisition speeds without reduction in sensitivity. This opened new frontiers for OCT applications by giving access to in vivo three-dimensional volumetric imaging within reasonable time constraints not previously available with time-domain detection OCT.
In this review of principles and applications of high-speed OCT, Maciej Wojtkowski, one of its early developers, presents a comprehensive picture of the field starting with comparison of physical fundamentals of OCT in both the time- and the Fourier domains. This picture includes the most commonly used variations of FdOCT: spectral OCT and swept-source OCT. Direct comparison of signal and noise components, sensitivity, and dynamic range of different OCT detection schemes as well as some specific constraints connected with each approach are described precisely. As expected for a review paper, Wojtkowski provides an historical overview of rapid-scanning OCT instrument developments both in time- and in Fourier domains for a full picture of OCT evolution over the past decade.
Well-selected examples illustrate high-speed OCT imaging applications with a special focus on ophthalmology, where OCT has revolutionized patient screening. At the cutting edge of OCT are physiological and functional imaging. Here, the author provides examples of high-speed Doppler OCT applications followed by optical measurements of neurophysiology and spectroscopic OCT. In the closing, Wojtkowski deliberates over imminent directions for high-speed OCT systems, predicting a high probability of OCT instruments achieving a speed of more than 1,000,000 A scans/s in the near future. This would require fast data processing and new algorithms for image processing, which can deliver more reliable and clinically significant information. He also points out that the combination of high-speed OCT with other imaging or functional techniques should enable creation of new multimodal platforms that can provide more valuable information about measured tissue.
To paraphrase the author’s words: The most crucial advance for many novel OCT applications was significant improvement of speed, enabling rapid acquisition rates that were necessary to reduce artifacts introduced by patient motion. As a result of high speed, in vivo 3D volumetric imaging on a large scale within reasonable time limits is now possible.
I recommend this review to both experts and novices who want to become familiar with state of the art OCT instrumentation and applications, as it draws a complete picture of this very exciting and fast-developing field.
-- Robert J. Zawadzki
|OCIS Codes:||(170.3880) Medical optics and biotechnology : Medical and biological imaging|
|(170.4500) Medical optics and biotechnology : Optical coherence tomography|
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