Detector development for a novel Positron Emission Mammography scanner based on YAP:Ce crystals

A prototype for positron emission mammography is under development within a collaboration of the Departments of Physics of Pisa and Ferrara. The device will be composed of two opposing detectors (parallel plane geometry). The active part of the detector head is constituted by a matrix of scintillators with a small pixel size (2 x 2 mm 2). We have evaluated the possibility to use an array of Position Sensitive PhotoMultiplier Tube (PSPMT mod R8520-C12 from Hamamatsu) for the readout of the scintillation matrix. Two different crystal-PMT coupling techniques have been explored: the results for each method are reported in this work. The overall performance, in terms of efficiency and pixel identification of the final prototype of the detector head are also presented. For future applications the new H8500 (also called the 'flat panel' PMT) has been studied and compared to the R8520 in terms of the imaging performance and other considerations such as cost and geometry. The imaging performance of these tubes is characterized in terms of the pixel image resolution and the peak-to-valley ratio. (C) 2004 Elsevier B.V. All rights reserved.