Recently a lab-scale single photon emission computed tomography (SPECT) system was constructed to study the details of the image formation process in an industrial SPECT system. The industrial SPECT system differs from a medical SPECT system in that it uses relatively large detectors and collimators in order to effectively detect high-energy gammas with enough collimation power, resulting always, however, in low-quality images. In this paper, a simple but very effective “double-layer” method is proposed as a means of improving the image quality of the industrial SPECT system. The rationale of the double-layer method is to simultaneously employ two layers of identical SPECT systems to increase the number of measurements points and, thereby, increase the image quality. The performance results of the double-layer method, as evaluated by Geant4 Monte Carlo simulations, showed dramatic improvement in image quality over those offered by the single-layer SPECT system. The improvement, additionally, was more marked for more complicated and higher-energy gamma sources.