π-scheme short-scan SPECT and image reconstruction

Because the effects of physical factors such as photon attenuation and spatial resolution are distance-dependent in single-photon emission computed tomography (SPECT), it is generally considered that accurate image reconstruction requires knowledge of the data function over 2π. In SPECT with only uniform attenuation, Noo and Wagner (2001) showed that an accurate image can be reconstructed from knowledge of the data function over π. In this work, we develop an heuristic perspective to demonstrate - and use simulation studies to confirm - that the data function in π-scheme SPECT with non-uniform attenuation contains complete information for an accurate image reconstruction. In its most general form, the proposed π-scheme SPECT entails data acquisition over disjoint angular intervals without conjugate views, totalling to π radians, thereby allowing flexibility in choosing projection views at which the emitted gamma-rays may undergo the least attenuation and blurring