Non-contact in vivo diffuse optical imaging using a time-gated scanning system.

Area of Science:

• Biomedical Optics
• Medical Imaging
• Spectroscopy

Background:

• Near-infrared spectroscopy (NIRS) is a valuable tool for non-invasive monitoring of tissue hemodynamics.
• Traditional NIRS systems often require direct contact with the tissue, limiting applications.
• Developing non-contact imaging methods is crucial for expanding NIRS capabilities.

Purpose of the Study:

• To design and evaluate a novel non-contact scanning imaging system for time-domain near-infrared spectroscopy (TD-NIRS).
• To assess the system's ability to detect hemodynamic changes in deeper tissues in vivo.
• To demonstrate the feasibility of non-contact absorption imaging for functional brain and motor tasks.

Main Methods:

• The system employs a null source-detector separation approach.
• It utilizes polarization-selective detection and a fast-gated single-photon avalanche diode.
• The system records late photons exclusively to enhance depth sensitivity.

Main Results:

• In vivo tests successfully recorded hemodynamics during arm occlusion.
• The system detected localized hemodynamic changes during a motor task.
• Non-localized hemodynamic changes were observed during a cognitive task.

Conclusions:

• The developed non-contact TD-NIRS system is feasible for in vivo imaging.
• The system can detect absorption changes in deeper tissues.
• This technology holds promise for advanced non-invasive functional imaging.