In a typical scintillation camera system, intrinsic resolution is dependent upon the accuracy of the identification of an interaction position. This paper intends to set up a evaluation tool based on Monte Carlo simulation for the purpose of estimating the intrinsic resolution of scintillation cameras. Monte Carlo N-Particles (MCNP) Code was applied to simulate the components of the model platform referred to Toshiba GCA-7100A with a monolithic Sodium Iodide (NaI) scintillator (40 x 40 x 0.9525 cm 3 ). The simulation result was 3.7 mm full width at half maximum (FWHM) for intrinsic resolution which came out to be in a good agreement with the experimental result.This suggests that our proposed evaluation tool may help to optimize the parameters of the detector without physical experiments.[7] M. Alnafea, K. Wells, N. M. Spyrou, M. . Saripan, M. Guy, and P.Hinton, "Preliminary results from a Monte Carlo study of breast tumour imaging with low-energy high-resolution collimator and a modified uniformly-redundant array-coded aperture," Nuclear Instruments