|
Diffuse Correlation Spectroscopy (DCS) is a non-invasive and easy to operate device for determining tissue perfusion in clinical applications. DCS detects temporal fluctuations in the diffusely reflected intensity from an incident coherent laser source and relates these fluctuations theoretically to calculate the mean-square displacement of moving light scattering particles. The objective of these studies was to experimentally investigate DCS signals from a turbid optical phantom containing a flow channel. By changing the depth of the flow channel (from the surface of the phantom) we investigated the depth sensitivity of DCS with changes in the optical properties of the phantom media containing the flow channel. Two sets of experiments were conducted: in the first task the sensitivity of the depth dependence of DCS measurements was investigated. The second task was to then determine how varying optical properties, within ranges measured in real tissue, altered the DCS measurements in regions of zero, low, and high relative flow rates. Concentrations of scattering and absorbing particles in the phantom surrounding the flowing solution were varied and the resulting changes in the autocorrelation curves were monitored. We report here that varying the concentrations of the absorbing and scattering particles in the phantom impacted the DCS autocorrelation decay measurements. Thus, it will be important to have robust estimates of the surrounding tissue optical properties to extract absolute flow-rates using DCS.
|
