A simulation study for SPECT multi-pinhole detector optimization

The aim of this study is to derive optimized parameters for a detector module employing scintillation crystal and multi-pinhole collimator which could be utilized in a variety of SPECT systems. A detector module was simulated to have 100 mm × 100 mm active area with 7 mm thick CsI(Tl) crystal. Monte Carlo simulation studies were performed to determine the optimal number of pinholes using Geant4 application for tomographic emission (GATE). The number of pinholes was varied from 1 to 225, with a 2 mm pinhole diameter and 50 mm focal length. Perpendicular lead septa were employed, between pinholes, to prevent projections from overlapping. Hot and cold rod phantoms were used to evaluate the performance of the proposed system. SPECT images were reconstructed using the OSEM algorithm. Activity distribution was well visualized, and 12 to 6 mm diameter rods could be resolved in the reconstructed images. In this study we have designed a multi-pinhole imaging system providing good resolution and system sensitivity over a large FOV. The detector module, applicable to various SPECT systems, could provide improved performance.