Time-resolved diffuse reflectance using small source-detector separation and fast single-photon gating

Phys Rev Lett. 2008 Apr 4;100(13):138101. doi: 10.1103/PhysRevLett.100.138101. Epub 2008 Mar 31.

Abstract

We demonstrate the feasibility of time-resolved diffuse reflectance measurements at small source-detector separations using a single-photon avalanche diode operated in time-gated mode. Photon time distributions at an interfiber distance of 2 mm were obtained on a homogeneous tissue phantom with a dynamic range of 10(6) and collecting photons at arrival times up to 4 ns. Moreover, we were able to detect a local inhomogeneity deeply buried within a diffusive medium with better spatial resolution, higher signal intensity, and same contrast of a larger (20 mm) interfiber distance. Finally, the proposed approach proved valuable to detect in vivo a task-related brain activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain / physiology*
  • Humans
  • Lasers, Semiconductor*
  • Motor Cortex / physiology
  • Photons*
  • Signal Processing, Computer-Assisted*