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dc.contributor.authorΜιχαήλ, Χρήστος Μ.ell
dc.contributor.authorΣπυροπούλου, Βασιλική Α.ell
dc.contributor.authorΦούντος, Γεώργιος Π.ell
dc.contributor.authorΚαλύβας, Νεκτάριος Ι.ell
dc.contributor.authorΒαλαής, Ιωάννης Γ.ell
dc.identifier.citationMichail, C., Spyropoulou, V., Fountos, G., Kalyvas, N., Valais, I., et al. (February 2011). Experimental and theoretical evaluation of a high resolution CMOS based detector under X-ray imaging conditions. Transactions on Nuclear Science. 58(1). pp. 314 - 322. IEEE.eng
dc.description.abstractFundamental imaging performance in terms of Modulation Transfer Function (MTF), Noise Power Spectrum (NPS) and Detective Quantum Efficiency (DQE) was investigated for a high resolution CMOS based imaging sensor. The device consists of a 33.91 mg/cm2 Gd2O2S:Tb scintillator screen, placed in direct contact with a CMOS photodiode array. The CMOS photodiode array, featuring 1200×1600 pixels with a pixel pitch of 22.5 μm, was used as an optical photon detector. In addition to the conventional frequency dependent parameters characterizing image quality, image information content was assessed through the application of information capacity (IC). The MTF was measured using the slanted-edge method to avoid aliasing while the Normalized NPS (NNPS) was determined by two-dimensional (2D) Fourier transforming of uniformly exposed images. Both measurements were performed under the representative radiation quality (RQA) settings, RQA-5 (70 kVp digital-radiography) and RQA-M2 (28 kVp digital-mammography) recommended by the International Electrotechnical Commission Reports 62220-1 and 62220-1-2 respectively. The DQE was assessed from the measured MTF, NPS and the direct entrance surface air-Kerma (ESAK) obtained from X-ray spectra measurement with a portable cadmium telluride (CdTe) detector. The ESAK values ranged between 11-87 μGy for RQA-5 and 6-40 μGy for RQA-M2. Additionally the output electrons per X-ray photon of the detector and its signal transfer characteristics were assessed via an analytical model, within the framework of the linear cascaded systems (LCS) theory. It was found that the detector response function was linear for the exposure ranges under investigation. Additionally our results showed that for the same RQA quality the output electrons per X-ray photon, as well as the measured and analytically predicted MTF, were not significantly affected by ESAK. MTF and DQE where found better compared to prev- - iously published data for other CCD and CMOS sensors, while the NNPS appeared to be comparable in the frequency range under investigation (0-10 cycles/mm).eng
dc.rightsΑναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ηνωμένες Πολιτείες*
dc.subjectX-ray imaging-
dc.subjectOptical transfer function-
dc.subjectΑπεικόνισης με ακτίνες Χ-
dc.subjectΟπτική συνάρτηση μεταφοράς-
dc.titleExperimental and theoretical evaluation of a high resolution CMOS based detector under X-ray imaging conditionseng
dc.typeΔημοσίευση σε περιοδικό-
heal.contributorNameΚανδαράκης, Ιωάννης Σ.ell
heal.contributorNameΠαναγιωτάκης, Γεώργιος Σ.ell
heal.contributorNameStudent Membereng
heal.identifier.secondaryDOI: 10.1109/TNS.2010.2094206-
heal.recordProviderΤ.Ε.Ι. Αθήνας. Σχολή Τεχνολογικών Εφαρμογών. Τμήμα Μηχανικών Βιοϊατρικής Τεχνολογίας Τ.Ε.ell
heal.journalNameTransactions on Nuclear Scienceeng
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