A new gamma camera based on hydrogenated amorphous silicon (a-Si:H) pixel arrays to be used in nuclear medicine is introduced. Various performance characteristics of a-Si:H imagers are reviewed and compared with those of currently used equipment. An important component in the a-Si:H imager is the scintillator screen. A new approach for fabrication of high resolution CsI(Tl) scintillator layers, appropriate for coupling with a-Si:H arrays, are presented. Using Monte Carlo Simulation, the performance of the new a-Si:H based gamma camera is evaluated.