Lossless Compression of List-Mode 3D PET Data

We describe lossless methods for compression of 3D PET data. Static list-mode data is re-sorted into sinograms and compressed using a combination of run-length and entropic coding. Dynamic list-mode data is compressed using 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 for static and dynamic data. In the dynamic case, we compare compression of multiple frame sinogram data with 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.