Abstract
Purpose: :
Introducing a novel optical coherence tomography (OCT) technique capable of imaging multiple retinal volumes per second without physical scanning.
Methods: :
An electronically tunable light source is interfaced to a modified commercial microscope via a highly multimode fiber. Full–field acquisition is performed with a standard medium–speed camera, capable of acquiring up to 150 full frames per second with up to 640x480 pixel resolution, thus eliminating the need for any mechanical scanning device. The image sequence, obtained under illumination in the infrared between 760 and 860 nm at equidistant optical frequency points is numerically reconstructed to complete three dimensional volumes of ex vivo retinal samples.
Results: :
Three dimensional optical imaging based on time–encoded frequency–domain optical coherence tomography has been performed on ex vivo retinal samples of different animal models. A scanning range of ∼5 x 4 x 0.5 mm (width x length x depth) at an axial resolution of ∼ 4 µm and transversal resolution of ∼ 5 µm in the focal region could be accomplished. Three–dimensional reconstructions of biological tissue acquired within less then a second consisting of more then 11 Megavoxel could be accomplished with the first generation prototype.
Conclusions: :
This novel OCT technique increases acquisition speed significantly without the need of any scanning device. Preliminary results on ex vivo retinal samples demonstrate the potential of this technique to be transferred to three–dimensional in vivo imaging of the anterior and posterior segment, acquiring multiple volumes per second. It is only limited by high speed electronics rather then slow mechanics, typically used in OCT. This technology promises to allow for real–time volume acquisition when combined with commercially available high speed cameras, enabling capture of multiple Gigavoxel per second. Parallel acquisition reduces the complexity and allows passing the speed limit of raster scanning OCT methods while keeping the exposure well within admissible tolerances.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • anterior segment