Development of a prototype detector for use in scintimammography imaging

In this paper we report the development of a prototype for a new kind of detector intended for scintimammography imaging. Traditional photon counting information is available; moreover digital words representing the amplitude of each event and suitable image elaboration methods significantly enhance detector capabilities. The prototype detector is composed of a collimator and 4 imaging modules. Each module is composed of an 8x8 sensing array of 2mm x 2mm low noise silicon p-i-n photodiode pixels, coupled to a CsI(Tl) scintillator and custom readout electronics. The sensor is fixed to an Al2O3 printed circuit board. Eight readout mixed analog-digital ICs, wire bonded to single sensor pixels and to the PCB, provide analog signal conditioning, A/D conversion, self-triggered acquisition and bidirectional serial data transfer. Digital signals are routed out so that each module can be attached to a main board with an FPGA for overall detector management. PC-based supervision of the detector is accomplished using a LabVIEW simplified graphical user interface. The purpose of the prototype is to test the approach and the chosen architecture; all its elements have been designed in order to permit the construction of the final detector with a significantly larger sensing area.