The advancement of diagnostic nuclear imaging systems is one of the most fruitful research areas. Conventional SPECT systems suffer from resolution-sensitivity trade-offs. This paper aims to investigate the performance of a novel SPECT nuclear imaging system proposed for small animal and brain imaging based on introducing the concept of the Laue lens as a part of a multi-pinhole collimation system. The proposed design is based on placing a Laue lens centered at each pinhole on a conventional multi-pinhole collimator. As an application, the system is optimized for the 140.6 KeV energy of Tc99. A lens-based SPECT imaging will open the door for light field image refocusing, the potential to have a system adapted to different organ size and shape. A more efficient SPECT system would also lead to a decrease in the dose of the injected radiotracers to the patient. A tracking Monte Carlo simulation is implemented in a MATLAB environment to predict the photon distribution of diffracted high energy photons. The obtained resolution of 0.1 mm would be an outstanding performance for SPECT in oncology imaging. One hit per 42 source photons was detected, corresponding to a sensitivity of 27 cps/MBq for one Laue lens. The attenuation, transmission, and absorption effects on the lens rings are also considered in this study. The comparison between the lens-based and conventional parallel LEHR SPECT is carried out in terms of system resolution, sensitivity, and the capacity to resolve adjacent submillimeter objects.