1. A theoretically exact local reconstruction method comprising reconstructing a region of interest (ROI) of an object into an image from local single photon emission computed tomography (SPECT) projection data of the ROI by modeling the projection data as an attenuated Radon transform comprising formula: P o ( θ , s ) = ∫ - ∞ ∞ f ( s θ + ? θ ⊥ )  ?  t ? indicates text missing or illegible when filed where P o represents the original projection data, f(x) is the image to be reconstructed, θ=(cos θ,sin(θ)), θ ⊥ =(−sin θ,cos(θ)), and μ(x) is the attenuation coefficient map.