New approach to obtain high resolution using conventional block designs in PET

High spatial resolution is essential to image small lesions in positron emission tomography (PET). Traditional methods suggest using small crystals to obtain high resolution. In this study, a novel method is introduced to achieve high spatial resolution by using scintillators with different decay times arranged in a checkerboard pattern. Pulse shape discrimination (PSD) was implemented to determine which crystal the gamma energy is deposited. In this work, 13×13 LSO and 13×13 LSO-GSO crystal arrays using 4×4×20 mm³ crystals were built and optimized using light sharing techniques. The average pixel resolution for the 13×13 LSO was measured to be 14.5%. Similarly, the average pixel resolutions for the GSO part of the 13×13 LSO-GSO crystal array and the LSO part of the same array were measured to be 13.9% and 18.5%, respectively. Due to the difference in the probability of forward scattering between GSO and LSO, the average energy resolution for LSO degraded from 14.5% to 18.5%. The average peak-to-valley ratios were measured to be 2.1 for the 13×13 LSO crystal array, 7.2 for the LSO part of the 13×13 LSO-GSO crystal array and 4.3 for the GSO part of the 13×13 LSO-GSO crystal array.