We have previously developed a method, slab derived scatter estimation (SDSE), for quickly and accurately modeling the asymmetric, spatially varying scatter response function in uniformly attenuating objects with convex surfaces. This model has been implemented in a projector-backprojector that, when combined with iterative reconstruction techniques, provides accurate scatter compensation in single-photon emission computed tomography (SPECT). These iterative reconstruction based scatter compensation techniques have the advantage that they use all detected photons, avoiding the noise amplification occurring with subtraction based schemes. In addition, scatter compensation with iterative reconstruction does not involve the use of arbitrary adjustable parameters. In this paper we present a new fast algorithm for implementing SDSE that reduces computation time by a factor of 16 compared to a direct implementation. Projection data computed with the new algorithm compare well with that from Monte Carlo simulations. When combined with faster computers and iterative reconstruction algorithms that converge rapidly, this fast projector-backprojector pair makes iterative reconstruction based scatter compensation feasible.
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Nuclear Energy and Engineering
- Electrical and Electronic Engineering