3D RECONSTRUCTION FOR A MULTIRING PET SCANNER BY SINGLE-SLICE REBINNING AND AXIAL DECONVOLUTION

A three-dimensional (3D) image reconstruction method, which was origin ally developed for a positron emission tomography (PET) system consist ing of two rotating scintillation cameras, has now been implemented fo r a multi-ring PET scanner with retractable septa. The method is calle d 'single-slice rebinning with axial deconvolution' (SSAD), and can be described as follows. The projection data are sorted into transaxial 2D sinograms. Correction for the axial blurring is made by deconvoluti on in the sinograms. To obtain the axial spread functions, which depen d on the activity distribution, 2D reconstruction is first made using a limited axial acceptance angle. The final 3D image is obtained by 2D , reconstruction of transaxial planes. The method is simple but not ap proximate, has a modest memory requirement, and can be combined with d ifferent 2D techniques. Evaluations by Monte Carlo simulations and pha ntom studies have been made.