Patent ID: 7391027

Claim:
A 3D image reconstructing method for a positron CT apparatus, comprising: a 3D data acquiring step for acquiring sinograms for each combination of ring pairs by collecting coincidence counting data of the ring pairs in each moving position, while moving a multi-ring detector having ring type detectors arranged in an axial direction and a bed having an object under examination placed thereon, relative to each other axially of the multi-ring detector; and a 3D image reconstructing step for performing 3D image reconstruction for RI distribution image reconstruction based on said sinograms acquired in said 3D data acquiring step; wherein said 3D data acquiring step is executed to acquire the sinograms while collating sinograms obtained in each position in time of moving the multi-ring detector to sinograms obtained in an immediately preceding position, and adding together sinograms of each ring pair acquired from the same site of the object; and wherein said 3D image reconstructing step is executed to read successively subsets of sinograms having been added, in parallel with said 3D data acquiring step, and to perform 3D iterative reconstruction, each time a subset is read, based on the subset read.