Correction for external LOR effects in listmode reconstruction for PET

In PET imaging listmode is an alternative for projections to store the acquisition data with more accuracy. The reconstruction starting from the listmode format requires different approaches than projection based algorithms. The ML-EM algorithm was modified to start from the listmode format. For listmode data mage degrading effects can be classified into two groups. Internal LOR effects (like attenuation, detection efficiency) do not lead to another LOR than the correct one, but only lead to a lower detection efficiency along the correct LOR. The correction for these effects can be done by using a sensitivity factor in the iterative algorithm. On the other hand there are also external LOR effects (scatter, randoms, resolution) which do lead to detection of wrong LORs. The correction for these effects can in principle be done by modifying the system matrix used in iterative reconstruction. For listmode reconstruction this system matrix can not be precalculated because of the very high ...

• Type: Conference
• Year: 2002
• Where: ISBI
• Authors: Stefaan Vandenberghe, Yves D'Asseler, Rik Van de Walle, Ignace Lemahieu
• Keywords: External Lor Effects, Internal LOR Effects, ISBI 2002, Medical Imaging, Range External Lor