A detailed investigation of non-iterative methods for 3D SPECT image reconstruction

The authors present an alternative approach for derivation of relationships between the ideal and modified sinograms in 3D SPECT with uniform attenuation and distance-dependent spatial resolution, and they investigate systematically the implication of the spatial resolution function on these relationships as well as on the ideal-sinogram estimation methods that are developed from these relationships. In the authors´ theory, the optical transfer function (OTF) of the resolution function is required to have a specific form. In this work, they develop a formula for converting a general OTF into this form so that their theory can be applied