Impact of Timing Resolution on DIRECT TOF PET Reconstruction with Sparse Detectors

Time-Of-Flight (TOF) information gives an accurate estimation of the location of annihilation, which can provide improved contrast-versus-noise and bias-versus-variance tradeoffs, and faster convergence in iterative reconstruction. On the other hand, manufacturing cost can be greatly reduced with the use of sparse detector configuration. The improved timing resolution may compensate image quality degradation caused by sensitivity loss of sparse detectors. So, it is possible to build a high performance long axial field of view (AFOV) PET scanner by improved timing resolution and sparsified detectors, without increasing the number of detectors as for the short AFOV PET scanner. In this work, we investigate the effect of improved timing resolution on TOF-PET reconstruction for the PET systems with dense and sparse detectors. The images are reconstructed by 3-D OP-OSEM within DIRECT data framework which allows very efficient reconstruction for high timing resolution list mode data. Our experiments indicate that sparse detectors with a high timing resolution can yield image quality comparable to that obtained from dense detectors with a low timing resolution.