Multi-distance diffuse optical spectroscopy with a single optode via hypotrochoidal scanning.

Area of Science:

• Biomedical Optics
• Spectroscopy
• Medical Imaging

Background:

• Frequency-domain diffuse optical spectroscopy (FD-DOS) is crucial for non-invasively assessing tissue optical properties and chromophore concentrations.
• Current FD-DOS systems often rely on manual probes or complex fiber arrays, limiting speed and flexibility in data acquisition.
• Generating 2D or 3D tissue maps typically requires extensive data from multiple locations.

Purpose of the Study:

• To introduce a new method for rapidly acquiring diverse source-detector (SD) separations using a single scanning SD pair.
• To enable high-speed, depth-resolved imaging of biological tissues with enhanced efficiency.
• To demonstrate the capability for generating B-scan images for localization of tissue inhomogeneities.

Main Methods:

• A mechanical scan head traces a hypotrochoidal pattern with a single SD pair over the sample.
• Integration with a high-speed FD-DOS system allows rapid collection of data across numerous SD separations.
• Linear translation of the device enables B-scan image generation for inhomogeneity mapping.

Main Results:

• The system achieved an average error of 4±2.6% for absorption and 2±1.8% for scattering across all SD separations.
• Demonstrated accurate determination of the size and location of absorbing inhomogeneities.
• Achieved near real-time rates for depth-resolved visualization of heterogeneous tissues.

Conclusions:

• Single optode diffuse optical scanning offers a promising approach for rapid, depth-resolved tissue visualization.
• The developed method significantly enhances the speed and efficiency of FD-DOS imaging.
• This technique holds potential for real-time assessment of biological tissue heterogeneity.