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Performance assessment of laser sources for time-domain diffuse correlation spectroscopy
Saeed Samaei1,2, Lorenzo Colombo3, Dawid Borycki2,4
1Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks. Trojdena 4, 02-109, Warsaw, Poland.
Biomedical Optics Express
|October 25, 2021
Summary
This study evaluated three lasers for time-domain diffuse correlation spectroscopy (TD-DCS) to measure blood flow. Laser performance was assessed using phantom and in vivo models, finding instrument response function (IRF) effects more critical than temporal coherence.
Area of Science:
- Biomedical Optics
- Medical Imaging
- Photonics
Background:
- Time-domain diffuse correlation spectroscopy (TD-DCS) noninvasively measures microvascular blood flow.
- TD-DCS requires specific laser characteristics, including a narrow instrument response function (IRF) and long coherence length, which are challenging to achieve simultaneously.
Purpose of the Study:
- To characterize and compare the performance of three different picosecond pulsed laser sources for TD-DCS applications.
- To evaluate the impact of laser properties, particularly the IRF, on TD-DCS measurements.
Main Methods:
- Characterization of laser emission spectrum and IRF.
- Phantom measurements to assess signal-to-noise ratio and sensitivity to velocity changes.
- In vivo measurements using an arterial occlusion protocol on human subjects.
Main Results:
- All three lasers demonstrated potential for laboratory and clinical TD-DCS use.
- The instrument response function (IRF) significantly impacted TD-DCS measurements.
- The impact of IRF was found to be more substantial than that of limited temporal coherence.
Conclusions:
- The choice of laser source, particularly its IRF, is crucial for optimal TD-DCS performance.
- Careful laser selection and characterization are necessary for reliable noninvasive blood flow measurements.
- The study provides valuable insights for selecting appropriate laser sources for TD-DCS instrumentation.
