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Rapid near-infrared diffuse tomography for hemodynamic imaging using a low-coherence wideband light source
1Oklahoma State University, School of Electrical and Computer Engineering, Stillwater, Oklahoma 74078-5032, USA. daqing.piao@okstate.edu
Journal of Biomedical Optics
|March 9, 2007
Summary
This study introduces a novel low-coherence source for rapid near-infrared diffuse optical tomography, enabling shift-free spectral encoding and improved imaging accuracy. This technique facilitates endoscopic imaging and captures hemoglobin changes during breath-holding.
Area of Science:
- Biomedical Optics
- Medical Imaging
- Optical Engineering
Background:
- Near-infrared (NIR) diffuse optical tomography (DOT) is a valuable non-invasive imaging technique.
- Previous spectral-encoding methods using multiple laser diodes faced limitations like shift-free encoding and channel fluctuations.
- Developing faster and more accurate NIR DOT systems is crucial for real-time physiological monitoring.
Purpose of the Study:
- To implement rapid NIR diffuse optical tomography using a low-coherence source with spread-spectral encoding.
- To compare the performance of this new method against previous spectral-encoding techniques.
- To demonstrate the feasibility of endoscopic NIR DOT and its application in physiological measurements.
Main Methods:
- Utilized a low-coherence superluminescent diode (840 nm, 40 nm bandwidth) as the light source.
- Employed spread-spectral encoding by dispersing the source bandwidth and coupling it to bundled fibers for parallel illumination.
- Implemented an 8x8 source-detector array (27 mm) achieving a sampling speed of 5 Hz.
Main Results:
- Achieved shift-free spectral encoding, reducing reconstruction uncertainty compared to multi-laser diode methods.
- Minimized spontaneous channel-to-channel intensity fluctuations, enhancing signal stability.
- Successfully demonstrated preliminary imaging of hemoglobin absorption variations during a 10-second voluntary breath-hold.
Conclusions:
- A low-coherence source enables efficient and accurate spread-spectral encoding for NIR DOT.
- The developed system offers advantages in speed, accuracy, and potential for endoscopic applications.
- This technique shows promise for non-invasive monitoring of physiological changes, such as blood oxygenation.
