@misc{oai:repo.qst.go.jp:00083625,
 author = {Kang, Hangyu and Kang, Hangyu},
 month = {Oct},
 note = {For mouse brain dedicated positron emission tomography (PET), depth-of-interaction (DOI) information is necessary to provide high resolution without compromising the sensitivity. In this study, we designed mouse brain PET with a staggered 4-layer DOI detector using 1 mm crystal pitch for high-resolution molecular imaging research. The proposed PET had a 50 mm ring diameter and 11 mm axial FOV. The proof-of-concept experimental results obtained with a single DOI detector showed good crystal map quality, resolving 95% of the crystals. Based on those results, we conducted GATE simulations to optimize the crystal layer configuration which can provide the best spatial resolution throughout the field-of-view. Three different crystal layer configurations were used: (1) uniform crystal layer (5+5+5+5 mm), (2) heterogenous crystal layer (3+3+4+10 mm), and (3) heterogenous crystal layer with a total thickness of 17 mm (3+3+4+7 mm). To evaluate the spatial resolution, five cylindrical sources (D=0.1 mm, L=10 mm) with spacing of 5 mm in the radial direction were used. In addition, an ultra-micro hot phantom was used to evaluate the imaging performance. The PET images were reconstructed by using an OSEM algorithm with 8 subsets and 10 iterations. An energy window of 400-600 keV was used for the image reconstruction and sensitivity calculation. The heterogenous crystal layer configuration (3+3+4+7 mm) showed the best spatial resolution (0.45 mm at center and 0.74 mm at 10 mm radial offset) among the three. The 0.75 mm rods of the ultra-micro hot phantom could be resolved with the peak-to-valley ratio of 1.57. In conclusion, the mouse brain PET with a staggered 4-layer DOI detector using the heterogenous crystal layer configuration (3+3+4+7 mm) can provide submillimeter resolution and 1.35% sensitivity. In the future, we plan to develop a prototype mouse brain PET scanner to validate the simulation results., 2021 Virtual IEEE Nuclear Science Symposium and Medical Imaging Conference},
 title = {Mouse Brain PET with a Staggered 4-Layer DOI Detector – Optimized Crystal Layer with GATE},
 year = {2021}
}