We propose a transportable Single Photon Emission Computed Tomograph (SPECT) device dedicated to the reconstruction of a radioactive tracer distribution in a process. The experimental device Is realized with 36 collimated sodium iodide detectors mounted around a bi-dimensional cylindrical box which simulates a mixing reactor vessel. The reconstruction is based on a statistical algorithm applied to a small number of views and detectors. Dynamic acquisitions coupled to video monitoring were performed after the injection of radioactive and dye tracers in the vessel. The analysis of first results show that the experimental SPECT method, based on a limited number of detectors, is hopeful for industrial needs. (C) 1997 Published by Elsevier Science Ltd. All rights.

A tomographic technique applied to fluid flow visualization is described. For industrial purposes, a relatively high energy tracer has to be used (200 keV to 2 MeV). The procedure implies the comprehension of the detection process relative to geometric response, attenuation, and scatter. This has been achieved by Monte Carlo investigations for four typical media. The formulation of a physical model allowed a set of weighting factors that were incorporated in the reconstruction algorithm. Experimental projections were compared to simulated projections for Monte Carlo validation. Results show that reconstruction of these data from a very limited number of projections is hopeful.