Dual-band optical coherence tomography using a single supercontinuum laser source

Abstract

, "Dual-band optical coherence tomography using a single supercontinuum laser source," J. Biomed. Opt. 21(6), 066013 (2016) Abstract. We developed a simultaneous visible-light (Vis) and near-infrared (NIR) dual-band optical coherence tomography (OCT) system using a single supercontinuum laser source. The goal was to benchmark our newly developed Vis-OCT against the well-developed NIR-OCT. The Vis-OCT subsystem operated at 91 nm full-widthat-half-maximum (FWHM) bandwidth centered at 566 nm; the NIR-OCT subsystem operated at 93 nm FWHM bandwidth centered at 841 nm. The axial resolutions were 1.8 and 4.4 μm in air for the Vis-and NIR-OCT subsystems, respectively. We compared the respective performances, including anatomical imaging, angiography, absolute retinal blood flow measurements, and spectroscopic analysis for retinal blood oxygen saturation (sO 2 ), between the two subsystems in rodents in vivo. While demonstrating minor discrepancies related to operation wavelengths, both subsystems showed comparable performances in the first three tests. However, we were only able to retrieve sO 2 using the Vis-OCT subsystem.

Colposcopic imaging using visible-light optical coherence tomography

“…Though conventional OCT uses near infrared (NIR) light source, recent technological advancement in supercontinuum lasers has facilitated the development of visible-light OCT (vis-OCT) for biomedical applications, [17][18][19] which can achieve much higher resolution than NIR OCT with comparable spectral bandwidth. 20 In addition to higher resolution, vis-OCT may provide better contrast. In biological tissue, the scattering coefficient often decreases with wavelength.…”

Angiographic and structural imaging using high axial resolution fiber-based visible-light OCT

“…1(C)). Considering that light passes the neutral density (ND) filter (Thorlabs, OD = 3.0) twice, the maximum sensitivity found was 89 dB, comparable to the sensitivity of systems built in free-space [33,40]. The 6 dB roll-off depth is 1.1 mm, which is enough to cover the whole retina.…”

“…Although visible light introduces discomfort in ocular imaging and is limited by a lower permissible exposure, it has been demonstrated by a Monte Carlo simulation that oxygen saturation (sO 2 ) quantification using infrared sources suffers from high inaccuracies [32]. A comparison between visible light and infrared OCT systems was performed previously [33], however the advantage of operating in the visible spectrum on axial resolution has not been exploited. As Eq.…”

Spectroscopic Doppler analysis for visible-light optical coherence tomography

“…[9][10][11] As a single imaging modality for rMRO 2 measurement, vis-OCT detects sO 2 by retrieving the absorption spectrum of blood from spectroscopic analysis and measures the flow rate using the established Doppler OCT method. [12][13][14] Compared with conventional OCT using nearinfrared (NIR) light, vis-OCT provides reliable sO 2 measurement and higher resolution, but has reduced measurement range of flow velocity. 13 This drawback of vis-OCT in flow measurement originates from the underlying mechanism of Doppler OCT, which relates phase shift between sequentially acquired OCT A-lines to the axial displacement of scatterers.…”

“…[12][13][14] Compared with conventional OCT using nearinfrared (NIR) light, vis-OCT provides reliable sO 2 measurement and higher resolution, but has reduced measurement range of flow velocity. 13 This drawback of vis-OCT in flow measurement originates from the underlying mechanism of Doppler OCT, which relates phase shift between sequentially acquired OCT A-lines to the axial displacement of scatterers. The axial displacement is converted to flow velocity based on the A-line rate of system and Doppler angle, which is the angle between the flow direction and light probing axis.…”