The industrial Single Photon Emission Computerized Tomography (SPECT) system comprised of 30 sets of lead collimated 2in. NaI(Tl) detectors was built and utilized for measuring the spatial distribution of radiotracers as a function of time at a predefined cross-sectional level of a tank with a diameter of 300mm and a height of 780mm. In a stable flow condition, a radiotracer was injected into the upstream of a tank and then the measurement data were processed for the two dimensional concentration mapping of the radiotracers with a time step of 1s. The images were compared with numerical simulation results obtained from the Computational Fluid Dynamics modeling that has been incorporated with several different kinds of turbulence models. The comparison shows one model gives a better result than any others in terms of the similarity of the radiotracer distribution pattern. This study demonstrates the significant possibility of industrial SPECT technology for visualizing flow characteristics in a multi-dimensional way and for validating the CFD modeling.