Effects of the instrument response function and the gate width in time-domain diffuse correlation spectroscopy: model...

Area of Science:

• Biomedical Optics
• Noninvasive Physiological Monitoring
• Optical Spectroscopy

Background:

• Time-domain diffuse correlation spectroscopy (TD-DCS) is a promising noninvasive optical technique.
• TD-DCS aims to measure blood flow (BF) and optical properties in biological tissues.
• Challenges exist in TD-DCS due to finite temporal resolution and gate width.

Purpose of the Study:

• To investigate the impact of finite temporal resolution and gate width on TD-DCS experiments.
• To develop a model for accurate BF retrieval from gated intensity autocorrelations.
• To enhance signal-to-noise ratio for in vivo TD-DCS applications.

Main Methods:

• Developed a model incorporating the instrument response function for BF retrieval from gated autocorrelations.
• Utilized numerical simulations with varying optical properties and source-detector separations.
• Conducted experiments using a homogeneous phantom to validate the model.

Main Results:

• The proposed model significantly reduced BF estimation errors in simulations (34% to 3%) and phantom experiments (37% to 2%).
• Broad time gates can be effectively used, improving signal-to-noise ratio.
• The model demonstrated accuracy across diverse optical properties and experimental configurations.

Conclusions:

• The developed model provides a robust tool for analyzing TD-DCS data, particularly for in vivo measurements.
• Accounting for the instrument response function is crucial for accurate BF quantification in TD-DCS.
• This work offers physical insights for optimizing TD-DCS system performance and data analysis.