Dual-mode line-field confocal optical coherence tomography for ultrahigh-resolution vertical and horizontal section imaging of human skin in vivo.

Olivier Levecq,Arnaud Dubois,Jonas Ogien,Hicham Azimani

doi:10.1364/boe.385303

Abstract

Line-field confocal optical coherence tomography (LC-OCT) is a recently introduced technique for ultrahigh-resolution vertical section (B-scan) imaging of human skin in vivo. This work presents a new implementation of the LC-OCT technique to obtain horizontal section images (C-scans) in addition to B-scans. C-scan imaging is achieved with this dual-mode LC-OCT system using a mirror galvanometer for lateral scanning along with a piezoelectric chip for modulation of the interferometric signal. A quasi-identical spatial resolution of ∼ 1 µm is measured for both B-scans and C-scans. The images are acquired in both modes at a rate of 10 frames per second. The horizontal field of view of the C-scans is 1.2 × 0.5 mm2, identical to the vertical field of view of the B-scans. The user can switch between the two modes by clicking a button. In vivo cellular-resolution imaging of human skin is demonstrated in both B-scan and C-scan modes, with the possibility to navigate within the skin tissues in real time.

Highlights

Line-field confocal optical coherence tomography (LC-OCT) is a recent imaging technique [1] based on the principle of time-domain OCT (TD-OCT) [2,3] with line illumination and line detection, that has been developed for acquiring vertical section images (B-scans) of skin tissues, in vivo, at ultrahigh resolution [4]
A single vertical scan is needed for the acquisition of a B-scan, during which focus tracking is performed, allowing the use of a high numerical aperture (NA) microscope objective to image with high lateral resolution
The lateral resolution in line-field frequency-domain OCT (FD-OCT) is limited to a few micrometers [14], while a lateral resolution of ⇠ 1 μm was demonstrated in LC-OCT [1]

Summary

Introduction

Line-field confocal optical coherence tomography (LC-OCT) is a recent imaging technique [1] based on the principle of time-domain OCT (TD-OCT) [2,3] with line illumination and line detection, that has been developed for acquiring vertical section images (B-scans) of skin tissues, in vivo, at ultrahigh resolution [4]. Line illumination of the sample to avoid lateral scanning of a light beam has been implemented in frequency-domain OCT (FD-OCT) [8,9,10,11,12,13]. Line-field FD-OCT su ers from a limitation in lateral resolution since the focus cannot be adjusted during the acquisition of the information in depth, as it is acquired in parallel. The lateral resolution in line-field FD-OCT is limited to a few micrometers [14], while a lateral resolution of ⇠ 1 μm was demonstrated in LC-OCT [1]

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Conclusion