Superresolution and Corrections to the Diffusion Approximation in   Optical Tomography
  We demonstrate that the spatial resolution of images in optical tomography is not limited to the fundamental length scale of one transport mean free path. This result is facilitated by the introduction of novel corrections to the standard integral equations of scattering theory within the diffusion approximation to the radiative transport equation. 
George Y. Panasyuk, Vadim A. Markel and John C. Schotland