Fully 3D uniform resolution transmission microPET image reconstruction

MAP (maximum a posteriori) reconstructions of transmission images produce more accurate ACFs (attenuation correction factors) than smoothed division of blank and transmission scans and analytical methods. Also, for highly specific tracers, transmission images can provide useful anatomical cues for use in localizing structures and image coregistration. The resolution of MAP images reconstructed with a spatially invariant smoothing prior is known to be nonuniform. Spatially variant smoothing parameters are used here to achieve uniform resolution throughout the transmission image. We also investigate the relationship between, resolution and the global smoothing parameter through computer simulations. The resulting calibration curve can be used to select the smoothing parameter to achieve a desired spatial resolution. The tractability and feasibility of our method is demonstrated through an application to phantom transmission data collected using a Concorde P4 microPET system.