Detector-pair-based normalization and realistic wobble correction for positron POSICAM HZ/HZL PET systems

For wobbled PET systems, such as the POSICAM HZ/HZL, sinogram-based normalization is not always accurate because, occasionally, synchronization between the circular motion of the rod source and the wobble motion of the PET system can produce artifacts in the calibration sinograms. When used on subsequent scans, the artifacts in the corrupted normalization sinograms could propagate into emission sinograms and produce artifacts in reconstructed images. In addition, the wobble motion of the system is not perfectly uniform, which will produce image artifacts if not properly corrected. We demonstrate that by using both detector-pair-based normalization, normalizing each detected event before it is binned into sinograms, and realistic wobble correction, utilizing the measured wobble position-time histogram, these image artifacts are reduced.