GPU based calculation of a SPECT projection operator for content adaptive mesh model

In this paper we explore the use of a graphical processing unit (GPU) in a fast calculation of a projection operator using a ray casting algorithm for a content-adaptive mesh model (CAMM). Previously we had introduced 2D and 3D tomographic image reconstruction using a CAMM for emission tomography (EM). The proposed GPU based projection operator calculation is fast and allows incorporation of a non-uniform attenuation and distance-dependent spatial resolution of the imaging system. The GPU allows for fast computation, therefore establishing a necessary step for the future practical development of a CAMM tomographic reconstruction.