Tomography, an inverse problem to recover inside an object by probing light and observing its output, is an important issue in physics, medical imaging, and related research fields. In this talk, we will present an approach to optical scattering tomography that uses discretized path integral to model the light transport. We make assumptions on a specific scattering model to facilitate the computation, then formulate an inverse problem to be solved by an interior point method. We will show some simulation results, comparisons with diffusion optical tomography, and conclude with future directions.