Spectroscopic and imaging capabilities of a pixellated photon counting system

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2001-06, Vol.466 (1), p.74-78
• Main Authors: Amendolia, S.R., Bisogni, M.G., Bottigli, U., Delogu, P., Dipasquale, G., Fantacci, M.E., Marchi, A., Marzulli, V.M., Oliva, P., Palmiero, R., Rosso, V., Stefanini, A., Stumbo, S., Zucca, S.
• Format: Article
• Language: English
• Subjects: Computer simulation; GaAs pixel detector; Image analysis; Image quality; Medical imaging; Microprocessor chips; Photon counting chip; Photons; Semiconducting gallium arsenide; Spectroscopy
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/S0168-9002(01)00827-0

We are studying the performance of various thickness GaAs pixel detectors bump-bonded to a dedicated photon counting chip (PCC) for medical imaging applications in different energy ranges. In this work we present the experimental results obtained with a 600 μm thick pixel matrix (64×64 square pixels, 170 μm side) in the 60–140 keV energy range to evaluate the possible use of such a system in the nuclear medicine field. In particular, we have measured the spectroscopic properties of the detector (charge collection efficiency, energy resolution and detection efficiency) and evaluated the discrimination capability of the electronics. Then we have measured the imaging properties of the whole system in terms of Point Spread Function and using a home made thyroid phantom. We present also a comparison with a traditional gamma camera and an evaluation, made by both experimental measurements and software simulations, of the imaging characteristics related to the use of a collimation system.