Data estimation for the ECAT HRRT sinograms by utilizing the DCT domain

The ECAT High Resolution Research Tomograph (HRRT) (CTI PET Systems, Knoxville, TN, USA) is a milestone positron emission tomography scanner in nuclear medicine imaging field. The gantry port of the HRRT is constructed by eight detector panels each of which is separated by 17 mm gaps from its neighboring detector panels. The existence of the gaps results in the missing parts in the acquired projection data. Consequently, the quantification of the reconstructed images is degraded if a method which requires complete dataset, such as Fourier rebinning or filtered backprojection (FBP), is applied without estimation of the missing data.