A new generation of flat panel photomultiplier tube (PMT) based on micro-channel plates (MCP) offers characteristics suitable for PET imaging. We are developing a preclinical PET system composed of four detection modules arranged around the animal. Each module consists in 768 LYSO:Ce crystals read at both ends by MCP-PMT. The particular geometry combined with an inner diameter of 61.2 mm lead to a high detection efficiency with a volumetric spatial resolution of 1 μL. The purpose of this work is to characterize the 1024 anodes of the MCP-PMT (Planacon XP85023/A1, Photonis Corp.) used in our preclinical PET system. The Planacon has very compact size (58 × 58 × 13.7 mm3) with an active area of 53 × 53 mm2. The anode array consists in a 32 × 32 matrix in which each individual anode is 1.4 × 1.4 mm2 with a pitch of 1.6 mm. Due to the lack of backside connectors and in order to individually readout the anode current, a dedicated connection board has been developed. The dark current, the gain and the timing resolution of one anode are measured as well as the charge sharing, the gain uniformity and the intrinsic spatial resolution on the entire active field of view. With a timing resolution below 100 ps, an intrinsic spatial resolution of 400 μm, a low dark current and a high gain, the Planacon XP85023/A1 offers a promising photodetector for PET imaging.