Abstract: Brain positron emission tomography (PET) plays an important role in the study of human brain function for biomedical. In order to significantly improve the quality of brain PET imaging, increase detection efficiency, and display images in real time, a specialized large-area panel detection system for brain PET imaging is designed, and preliminary experimental tests are carried out for this design. The PET detection system consists of two large-area probes, each containing a 3×3 array of position-sensitive photomultiplier tubes and multiple tightly arranged array-type Cerium and Yttrium Doped Lutetium Oxyorthosilicate (Ce:LYSO) scintillation crystals. A ²²Na point source with 1 μCi was used to test the crystal properties of LYSO crystal arrays with pixels sized from 0.7 mm×0.7 mm to 2.0 mm×2.0 mm. And two LYSO crystal arrays with pixels of 1.5 mm×1.5 mm were selected for preliminary tomography of one-to-one coincidence detection. The experimental results show that the average FWHMs of position discriminating profiles of LYSO crystal arrays with various pixels are between 0.38 mm and 0.49 mm, and the average values of energy resolution (FWHM) are between 20% and 30%. In the initial image tomography test of ²²Na point source, the resolution of reconstructed image is obtained as 1.5 mm by filtering back projection algorithm, which verifies the feasibility of large-area panel detection system.