List mode 3D PET reconstruction using an exact system matrix and polar voxels

This paper describes a computational experiment to examine the feasibility of full 3D PET reconstruction using MLEM and OSEM using unbinned list mode date and an exact system matrix. A key feature of the approach is the use of polar pixels in the transverse plane to allow a full exploitation of the axial symmetry of the detector elements and hence permit the storage of an exact precomputed system matrix.