A fast SPAD-based small animal imager for early-photon diffuse optical tomography.

Area of Science:

• Biomedical optics
• Medical imaging
• Photonics

Background:

• Photon scattering in biological tissue degrades near-infrared diffuse optical tomography (DOT) imaging.
• Utilizing early-arriving photons, which undergo fewer scattering events, can mitigate this degradation.
• Single photon avalanche photodiodes (SPADs) offer superior temporal resolution compared to photomultiplier tubes (PMTs) for detecting these early photons.

Purpose of the Study:

• To develop and validate a fast SPAD-based time-resolved diffuse optical tomography system.
• To demonstrate the effectiveness of using early-arriving photons for improved DOT imaging.
• To establish a foundation for in vivo applications and time-resolved fluorescence measurements.

Main Methods:

• Developed a novel, fast SPAD-based system for time-resolved diffuse optical tomography.
• Acquired full time-resolved photon data from an optical phantom with absorbing inclusions.
• Performed image reconstruction using exclusively early-arriving photon data.

Main Results:

• The SPAD-based system successfully acquired time-resolved data from an optical phantom.
• Image reconstruction using early-arriving photons demonstrated significant improvements over time-integrated data.
• The system's performance validates the approach of selecting early photons to enhance DOT imaging.

Conclusions:

• A fast SPAD-based time-resolved DOT system has been successfully developed and validated.
• Analyzing early-arriving photons is a highly effective strategy for improving DOT image quality by reducing scattering artifacts.
• This technology holds promise for future in vivo studies and advanced optical imaging techniques.