RESUMO
A prototype for positron emission mammography is under development at the Department of Physics of Pisa University. The device will be composed of two opposing detectors (parallel plane geometry). The active part of each detector head consists of a matrix of 900 YAP: Ce pixel scintillators, with a 2x2 mm(2) pitch and a 30 mm thickness. The read out is performed by an array of nine metal channel dynode PSPMTS (mod. R8520-00-C12) from Hamamatsu. In the previous version of the head, the PSPMTS were independently read out. For the clinical implementation of the prototype we have designed a simplified circuitry for the readout of the nine tubes based on a multiplexed resistive divider, reducing the number of channels from 36 to 4. A simulation study for an optimised amplifier has been carried out. The housing for each of the two yap-pem detectors has been fully engineered and is in the assembly stage.