|
内容記述 |
[Purpose]For small animal positron emission tomography (PET), spatial resolution is the most important parameter to visualize neurological function. However, spatial resolution of conventional PET has been limited to over 0.5 mm because of unoptimized detector designs. The aim of this study is to develop a sub-0.5 mm resolution PET scanner for neuroimaging of mouse brain. [Methods]The developed PET scanner has a ring diameter of 48 mm and axial coverage of 23.4 mm. The PET scanner consists of 32 depth-of-interaction (DOI) detectors, each of which consists of staggered 3-layer LYSO crystal array (0.8 mm pitch) and SiPM 5×5 array (2.4 mm pitch). The 1st, 2nd, and 3rd crystal layers have 3-, 3-, and 5-mm thicknesses resulting in a total thickness of 11 mm. The SiPM signals were multiplexed and digitized by custom-made front-end electronics and data acquisition system. To evaluate imaging performance, a resolution phantom filled with 18F was scanned and reconstructed with iterative algorithm. We carried out in vivo mouse brain imaging with 18F-FDG tracer.[Results]The developed PET scanner resolved the 0.45 mm diameter rods of the resolution phantom clearly, which were barely identified with a conventional PET scanner. With the developed PET scanner, the small mouse brain structures, such as the hypothalamus, and cerebellar nuclei were identified for the first time.[Conclusion]In conclusion, we successfully developed the PET scanner that can provide sub-0.5 mm resolution. The developed PET will give a new insight into neuroscience research using rodent models. |
