Joint activity and attenuation reconstruction of listmode TOF-PET data

Different methods have been proposed for simultaneous reconstruction of activity and attenuation from TOF-PET sinogram data. In this work we present the listmode maximum likelihood activity and attenuation reconstruction (MLAA) and the listmode maximum likelihood attenuation correction factors (MLACF) algorithms building on their established sinogram implementation. Our listmode MLAA differs from a recently proposed listmode algorithm by incorporating the maximum likelihood transmission reconstruction (MLTR) algorithm in MLAA. The listmode MLTR algorithm has some similarity to the listmode image based reconstruction algorithm (ISRA), since it reconstructs the image from the backprojection of the acquired data. We investigate the reconstruction results on a scan of the NEMA IEC body phantom.