Point spread functions of photons in time-resolved transillumination experiments using simple scaling arguments

Simple scaling arguments are used to determine spatial resolution achievable in time-resolved transillumination experiments involving highly diffuse media. These arguments allow us to obtain relationships linking target resolution at different planes inside an optically turbid slab to the gating times of the imaging system. We show that this approach yields the same results as those obtained previously from an approximate and rather complicated analytical derivation. In addition, we are now able to assess the effects of scattering anisotropy on spatial resolution attainable when gating times are so short that a constant scaling of photon transport scattering length is not appropriate. These results should enable one to devise more accurate and simpler image reconstruction algorithms.