high performance computing on graphics processing units: hgpu.org

In this manuscript, we present a preliminary evaluation of a fully 3D projection operator calculation aimed at emission tomography on a non-circular orbit. The proposed methodology uses the content-adaptive mesh model (CAMM) for volumetric data representation. The CAMM is an efficient data representation based on adaptive non-uniform sampling and linear interpolation. The presented projection operator model incorporates the major data degradation models, namely object attenuation and detector-collimator spatial response, referred to as distance dependent blur. The projection operator is calculated using a ray-casting algorithm and can be adjusted to any scanning geometry and collimator design (e.g. parallel, focusing and pinhole). Open CL implementation allows shortening of computation time in comparison to standard single CPU implementation. In this work we successfully tested implementation of the CAMM projection operator by reconstructing images obtained from a realistic data simulation with SIMIND on a non-circular camera orbit. In the future, we will add other collimator designs.