Author :
Amendolia, S.R. ; Bisogni, M.G. ; Bottigli, U. ; Ciocci, M.A. ; Delogu, P. ; Dipasquale, G. ; Fantacci, M.E. ; Giannelli, M. ; Maestro, P. ; Marzulli, V.M. ; Pernigotti, E. ; Rosso, V. ; Stefanini, A. ; Stumbo, S.
Abstract :
A digital mammography system based on a GaAs pixel detector has been developed by the INFN (Istituto Nazionale di Fisica Nucleare) collaboration MED46. The high atomic number makes the GaAs a very efficient material for low energy X-ray detection (10-30 keV is the typical energy range used in mammography). Low contrast details can be detected with a significant dose reduction to the patient. The system presented in this paper consists of a 4096 pixel matrix built on a 200 μm thick semi-insulating GaAs substrate. The pixel size is 170×170 μm2 for a total active area of 1.18 cm2 . The detector is bump-bonded to a VLSI front-end chip which implements a single-photon counting architecture. This feature allows to enhance the radiographic contrast detection with respect to charge integrating devices. The system has been tested by using a standard mammographic tube. Images of mammographic phantoms will be presented and compared with radiographs obtained with traditional film/screen systems. Monte Carlo simulations have been also performed to evaluate the imaging capability of the system. Comparison with simulations and experimental results will be shown
Keywords :
Monte Carlo methods; mammography; semiconductor counters; GaAs; GaAs pixel detector; Monte Carlo simulation; VLSI front-end chip; digital mammography; low energy X-ray detection; mammographic phantoms; single-photon counting; Collaboration; Detectors; Gallium arsenide; Mammography; Optical imaging; Pixel; Radiography; Substrates; Very large scale integration; X-ray detection;
