Lossless compression of dynamic PET data

We describe two approaches to lossless compression of dynamic PET data. In the first, a sequence of sinogram frames are compressed using differential, encoding. followed by lossless entropy-based compression. The second approach applies lossless compression to data stored in a sinogram/timogram format in which the arrival times of each photon,pair are stored in spatial order, indexed by the sinogram. Compression of the timogram is performed using entropic coding of the differential arrival times in each sinogram bin. We describe these compression methods and present results from simulated and real data comparing multiframe and sinogram/timogram formats. Both formats produce substantial reductions in data size compared to the raw data, with higher compression factors achieved using the sinogram/timogram format when high temporal resolution is required.