  Imaging depth of optical microscopy has been fundamentally limited to
millimeter or sub-millimeter due to light scattering. X-ray microscopy can
resolve spatial details of few microns deeply inside a sample but the contrast
resolution is still inadequate to depict heterogeneous features at cellular or
sub-cellular levels. To enhance and enrich biological contrast at large imaging
depth, various nanoparticles are introduced and become essential to basic
research and molecular medicine. Nanoparticles can be functionalized as imaging
probes, similar to fluorescent and bioluminescent proteins. LiGa5O8:Cr3+
nanoparticles were recently synthesized to facilitate luminescence energy
storage with x-ray pre-excitation and the subsequently stimulated luminescence
emission by visible/near-infrared (NIR) light. In this paper, we suggest a
micro-modulated luminescence tomography (MLT) approach to quantify a
nanophosphor distribution in a thick biological sample with high resolution.
Our numerical simulation studies demonstrate the feasibility of the proposed
approach.
