PET ellipse phantom, CTI Exact System
These images were reconstructed from a PET scan of an elliptical phantom containing spheres of various activity in a warm background. The top row is penalized likelihood based on the shifted Poisson model, reconstructed using the "parabaloidal surrogates coordinate ascent" algorithm to be presented at NSS/MIC 1998. The bottom row is FBP.
Here is the central horizontal profile through center images. The spatial resolution of the PL image is at least as good as that of the FBP image, yet the noise in the uniform background is reduced.
The top two images
were formed using penalized-likelihood (PL) emission reconstruction
and PL transmission reconstruction.
The bottom two images
were formed using FBP emission reconstruction,
and conventional attenuation correction.
The left images were formed from a 12 minute tranmission scan,
and the right images were formed from a 2 minute transmission scan.
The statististical reconstruction methods
degrade more gracefully
in the presence of short transmission scans.
Left is FBP, right is penalized likelihood.
