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内容記述 |
Objectives: Spatial resolution is the most important factor for mouse brain imaging. However, the spatial resolution of PET has been limited to over 0.5 mm due not only to the positron range and the angular deviation but also to unoptimized detector designs. Here we present a sub-0.5 mm resolution PET scanner for rodent neuroimaging.Methods: The proposed mouse brain PET scanner had a 48 mm ring diameter and 23.4 mm axial field-of-view. The PET scanner consisted of 2 rings, each of which had 32 depth-of-interaction (DOI) detectors. Each DOI detector had a 3-layer LYSO crystal array with a crystal pitch of 0.8 mm and a 5×5 SiPM array with a pixel pitch of 2.4 mm. The SiPM anode signals were multiplexed using a resistive network and then digitized by a custom-made DAQ system. The physical performance was evaluated by the NEMA NU4 standard. A resolution phantom was scanned for imaging performance evaluation. In vivo mouse brain imaging was performed with 18F-FITM ([4-18Ffluoro-N-[4-[6-(isopropylamino)pyrimidin-4-yl]-1,3-thiazol-2-yl]-Nmethylbenzamide]) tracer. Results: The measured spatial resolutions at the center and 5 mm radial offset were 0.68 mm and 0.71 mm for FBP, respectively. The 0.45 mm rod structures of the resolution phantom were resolved clearly using the OSEM algorithm. The moue brain structures, such as the amygdala and cerebellar nucleus, were clearly resolved.Conclusions: We successfully developed a sub-0.5 mm resolution PET scanner, which can pave the way for neuroscience research using rodent models, especially those with neurodegenerative diseases. |
