Development of a Monte Carlo-wave model to simulate time domain diffuse correlation spectroscopy measurements from
Xiaojun Cheng1, Hui Chen2, Edbert J Sie2
1Boston University, Neurophotonics Center, Department of Biomedical Engineering, Boston, Massachusett, United States.
Journal of Biomedical Optics
|February 24, 2022
Summary
A new model simulates time-domain diffuse correlation spectroscopy (TD-DCS) for non-invasive blood flow measurement. While TD-DCS did not outperform continuous-wave DCS in simulations, the model aids future development and identifies potential use cases.
Area of Science:
- Biomedical Optics
- Non-invasive Physiological Monitoring
- Optical Spectroscopy
Background:
- Diffuse Correlation Spectroscopy (DCS) is a non-invasive optical technique for continuous blood flow measurement.
- Time-domain DCS (TD-DCS) offers potential for improved brain depth sensitivity and distinguishing superficial from deep blood flow.
- A predictive model for TD-DCS performance compared to continuous-wave DCS (CW-DCS) is currently lacking, hindering system development.
Purpose of the Study:
- To establish a first-principles simulation model for TD-DCS measurements.
- To enable analysis of measurement noise and quantify TD-DCS system performance for various geometries.
- To provide a tool for comparing TD-DCS with CW-DCS.
Main Methods:
- Integrated Monte Carlo simulations of photon scattering with wave models of speckle intensity fluctuations.
- Simulated photon counts as a function of time for both CW-DCS and TD-DCS.
- Incorporated factors including laser coherence, instrument response, detector gating, speckle statistics, and shot noise.
Main Results:
- Developed a Monte Carlo-Wave model capable of simulating CW-DCS and TD-DCS measurements from first principles.
- Simulations did not identify realistic conditions where TD-DCS outperformed CW-DCS.
- The model's code was made publicly available to facilitate further research and identification of favorable TD-DCS use cases.
Conclusions:
- The developed model provides a quantitative tool for predicting TD-DCS performance.
- While TD-DCS did not outperform CW-DCS under tested conditions, further exploration of the complex parameter space may reveal advantages.
- TD-DCS shows promise for measuring deep brain tissue dynamics, benefiting advanced DCS systems and image reconstruction.
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