We have developed a conformal positron emission tomography (PET) scanner prototype with a decagon geometry for human brain imaging based on our single-ended readout prism-PET depth-encoding detector modules. The scanner consists of 40 prism-PET detector modules arranged in a short diameter of 29.1 cm and a long diameter of 38.5 cm decagonshaped ring with the axial field of view (FOV) of 25.5 mm. The Prism-PET detector module consists of a 16 × 16 array of 1.5 × 1.5 × 20 mm3 lutetiumyttrium oxyorthosillicate (LYSO) scintillator crystals with 1.6 mm crystal pitch coupled 4-to-1 on one end to an 8 x 8 multipixel photon counters (MPPC) readout arrays with 3.2 × 3.2 mm2 silicon photomultipliers (SiPM) pixels and to a prismatoid light guide on the opposite end.