System Response Matrix Calculation Based on Distance-Driven Model and Solid Angle Model for Dual-Head PET System

Abstract

The dual-head positron emission tomography (PET) systems have an importance role in the preclinical and clinical applications. This paper focuses on developing a simplified model based on distance-driven (DD) and solid angle method to calculate the system response matrix (SRM) for the dual-head PET system. The subsampling schemes, including the subvoxel scheme and multi-DD scheme were introduced. The full width at half maximum (FWHM), coefficient of variation (COV), and contrast were computed and compared with that of using the Monte Carlo (MC)-based and multiray methods. In this paper, the dual-head PET system is configured with a 5 cm separation and $52 \times 104$ mm3 detection area of each head. The size of each crystal is $13\times 1.89\times 1.89$ mm3. The results indicate that the rods with 1.0 mm diameter are resolved basically with the 100th iteration when the voxel is virtually divided into $2\times 2\times 2$ and $4\times 4\times 4$ subvoxels, which is comparable to that with the MC-based SRM. When the voxel is divided into four cuboid-shaped subvoxels, the rods with 1.0 mm diameter are resolved with the 80th iteration and the COV performs well in the simulation experiment. Overall, the proposed SRM model achieves a good compromise between image quality and calculation time.