3D reconstruction for a multi-ring PET scanner

A three-dimensional image reconstruction method, originally developed for a rotating PET scanner, has been implemented for a multi-ring PET scanner with retractable septa. The method is based on single slice rebinning and axial deconvolution of an activity distribution dependent spread function. The final 3D image is obtained by 2D reconstruction of transaxial planes. The axial deconvolution is made using an iterative Landweber-type algorithm. In this work the authors have investigated two alternative approaches for the deconvolution step; (1) using all the data in the calculation; and (2) deconvolving only the cross-plane events. The resolution and noise-level has been studied for different number of iterations using the two approaches. The authors conclude that the second approach results in a noise-level that is more stable with increasing number of iterations. However, one single iteration seems to be sufficient to obtain an axial resolution comparable to the one in 2D acquisition mode