Laparoscopic real-time en-face differential optical topography of   near-surface heterogeneity by using an applicator probe with the   maximum-density radially alternating illumination and detection   fiber-channels
  We demonstrate a laparoscopic applicator probe and a method thereof for real-time en-face topographic mapping of near-surface heterogeneity for potential use in intraoperative margin assessment during minimally invasive oncological procedures. The probe fits in a 12mm port and houses at its maximum 128 copper-coated 750um fibers that form radially alternating illumination (70 fibers) and detection (58 fibers) channels. By simultaneously illuminating the 70 source channels of the probe that is in contact with a scattering medium and concurrently measuring the light diffusely propagated to the 58 detector channels, the presence of near-surface optical heterogeneities can be resolved in an en-face 9.5mm field-of-view in real-time. Visualization of a subsurface margin of strong attenuation contrast at a depth up to 3mm is demonstrated at one wavelength at a frame rate of 1.25Hz. 
Daqing Piao, Kenneth E. Bartels, G. Reed Holyoak, Sanjay Patel
physics.med-ph