A dual plane orbit approach for improved pinhole tomography

We investigate the effect of dual parallel plane orbits on pinhole reconstruction quality. Projections taken of a micro-Defrise phantom for two parallel, circular orbits are reconstructed using an OSEM algorithm. We hypothesize that a dual parallel orbit scan will provide greater coverage for pixels that do not lie in the orbit plane, thus reducing the axial blurring effect seen with single orbit pinhole scans while also increasing axial field-of-view as compared to a single orbit. Experiments were performed with simulated computer phantoms, and a physical micro-Defrise phantom imaged with a prototype small animal SPECT scanner fitted with a 0.75 mm pinhole collimator. We found that for the simulation and experimental data, dual plane reconstruction showed better resolution away from the orbit plane, improved uniformity, and reduced distortion as compared to a single orbit.