Researchers led by Jeroen Kalkman, University of Amsterdam, The Netherlands, have developed a Fourier-domain optical coherence tomography (OCT) method to measure the movement of particles in complex geometries, such as biological tissue, with high accuracy and speed.

OCT employs a broadband light source to light up the target tissue. Transmitted light is captured and recorded with a spectrometer and high-speed camera. The recorded images are analyzed with Fourier techniques to increase the particle diffusion imaging speed by a factor of 200.

By analyzing the time dependent behavior as well as the static OCT images, the researchers could measure viscosity, particle dynamics, flow of fluids and diffusion rates. Potential applications of this technique are to quantify blood flow in tissue, among others.

• Path-Length-Resolved Diffusive Particle Dynamics in Spectral-Domain Optical Coherence Tomography
  J. Kalkman, R. Sprik, T. G. van Leeuwen,
  Phys. Rev. Lett. 2010, 105, 198302.
  DOI: 10.1103/PhysRevLett.105.198302