Characterization of a mammographic system based on single photon counting pixel arrays coupled to GaAs x-ray detectors

Journal Article · Wed Apr 15 00:00:00 EDT 2009 · Medical Physics

DOI:https://doi.org/10.1118/1.3097284· OSTI ID:22095329

Amendolia, S. R.; Bisogni, M. G.; Delogu, P.; Fantacci, M. E.; Paternoster, G.; Rosso, V.; Stefanini, A. ^[1]

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1. Str. Dip. di Matematica e Fisica dell'Universita di Sassari, Via Vienna 2, I-07100, Sassari (Italy) and Istituto Nazionale di Fisica Nucleare INFN Sezione di Pisa, Largo B. Pontecorvo 3, I-56127, Pisa (Italy)

The authors report on the imaging capabilities of a mammographic system demonstrator based on GaAs pixel detectors operating in single photon counting (SPC) mode. The system imaging performances have been assessed by means of the transfer functions: The modulation transfer function (MTF), the normalized noise power spectrum, and the detective quantum efficiency (DQE) have been measured following the guidelines of the IEC 62220-1-2 protocol. The transfer function analysis has shown the high spatial resolution capabilities of the GaAs detectors. The MTF calculated at the Nyquist frequency (2.94 cycles/mm) is indeed 60%. The DQE, measured with a standard mammographic beam setup (Mo/Mo, 28 kVp, with 4 mm Al added filter) and calculated at zero frequency, is 46%. Aiming to further improve the system's image quality, the authors investigate the DQE limiting factors and show that they are mainly related to system engineering. For example, the authors show that optimization of the image equalization procedure increases the DQE(0) up to 74%, which is better than the DQE(0) of most clinical mammographic systems. The authors show how the high detection efficiency of GaAs detectors and the noise discrimination associated with the SPC technology allow optimizing the image quality in mammography. In conclusion, the authors propose technological solutions to exploit to the utmost the potentiality of GaAs detectors coupled to SPC electronics.

• OSTI ID: 22095329
• Journal Information: Medical Physics, Vol. 36, Issue 4; Other Information: (c) 2009 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
62 RADIOLOGY AND NUCLEAR MEDICINE
BIOMEDICAL RADIOGRAPHY
EQUIPMENT
GALLIUM ARSENIDES
IMAGES
MAMMARY GLANDS
OPTIMIZATION
PERFORMANCE
PHOTONS
POSITION SENSITIVE DETECTORS
QUANTUM EFFICIENCY
SEMICONDUCTOR DETECTORS
SPATIAL RESOLUTION
TRANSFER FUNCTIONS
X RADIATION
X-RAY DETECTION