| Applications |
| |
 |
| Art Conservation |
| |
 |
| Retina Imaging |
| |
 |
| Drug Coating |
| |
 |
| Polarization Sensitive OCT |
| |
 |
| AO enhanced OCT |
| |
 |
| Cochlear Implantation |
| |
 |
| Doppler OCT |
| |
 |
| Mouse Lung |
 |
| Endoscopic Imaging |
| |
 |
| Functional Imaging |
| |
 |
| Developmental Biology |
| |
 |
| 3D Imaging |
| |
| Nature Photonics |
| Peer Reviewed Papers |
|
|
Doppler OCT
Doppler OCT, also known as Optical Doppler Tomography or ODT, provides flow velocity measurement in the sample. It uses the laser-induced Doppler frequency shift as the contrast mechanism for image construction. When combined with standard OCT imaging, the high-spatial resolution (3-10 µm) of OCT and high velocity sensitivity of Doppler OCT (50-100 µm/s) allow sample structural imaging and flow velocity measurement simultaneously, making this a powerful tool for mapping fluid flow in the sample. Typical applications of Doppler OCT include studying embryo cardiac dynamics in developmental biology, vascular pathology and treatment response, and flow velocimetry in micro-fluidic channels.
We report the development of a high-speed Doppler enhanced swept source Optical Coherence Tomography (OCT) imaging system. Real-time in-vivo imaging of an African tadpole beating heart is shown in Figure 1. The Doppler enhanced imaging capability was developed based on Thorlabs swept source OCT microscope systems (Thorlabs OCM1300SS), in collaboration with Adrian Mariampillai and Victor Yang at the University of Toronto and Ryerson University.
 |
| Figure 1: The data represents a series of 25 consecutive in vivo cross-sectional images of an African tadpole heart with superimposed Doppler data. The OCT signal reveals the structural information about the sample, while the color Doppler signal gives real time information on blood flow, as well as bulk motion. |
|
The swept source based Doppler OCT has been successfully applied for gated 2D and 3D imaging of the heart beat cycle of small animals (A. Mariampillai, et. al, Optics Express, 15 (4), 1627, 2007). Figure 2 shows the experimental setup of the imaging system.
 |
| Figure 2. Imaging setup. (a) SS: swept source, FC: fiber coupler, PC: polarization controller, CIR: circulator, C: collimator, M: mirror, BD: balanced detector, DAQ: data acquisition board, GM: galvo mirrors, L: lens, TD-OCT: time-domain OCT system, P:GRIN fiber probe.. (b) GRIN fiber probe positioned to image blood flow in one of the great vessels coming from the heart (tadpole in the ventral position). The TD-OCT system begins continuously acquiring data when it receives a trigger signal sent from the DAQ system of the SS-DOCT system. |
|
Figure 3a and 3b show the Structure and blood flow movies from the Xenopus laevis heart acquired at 12 fps in real-time, processed using optical cardiogram gated technique to produce effective frame rate of 1000 fps, and played back at 30 fps.
 |
 |
| Figure 3. (a) Cross-sectional structural movie at the level of the aortic arches. Vessel walls and blood pumped through the vessels are clearly seen. (b) Doppler movie at the same position, demonstrating flow through the vessels and the wall motion. RAo: right aortic arch, LAo: left aortic arch and V: pulmonary/gill vessels. |
|
Figure 4 shows a surface reconstruction of the tadpole heart, rotating while beating, to demonstrate the dynamic anatomical relationships. The entire 4D data set can be used to illustrate the complex cardiac motion during a heart beat cycle. For example, the truncus arteriosis (TA) oscillates over a significant distance relative to the right and left atria (RA and LA), which are situated more posterior. During each cardiac cycle, the TA not only changes position, but its shape and diameter also vary periodically to accommodate the output blood flow from the ventricle (V).
 |
| Figure 4. 4D surface reconstruction of the tadpole heart demonstrating the complex cardiac motion, and the relative position of the various components (V: ventricle, TA: truncus arteriosis, RA: right atrium, RAo: right aortic arch, LAo: left aortic arch, LA: left atrium) of the heart. |
|
Image & Movie Courtesy: 2007 Optical Society of America, Prof. Victor X. D. Yang, Department of Physics, Ryerson University, and Adrian Mariampillai, Depts. of Medical Biophysics, University of Toronto.
|
|
| Product Links |
| |
 |
| Swept Source OCT Microscope System |
| |
 |
| Spectral Radar OCT Imaging System |
| |
 |
| Rapidly Swept Tunable Laser |
| |
| |
|
( 0)