Modeling indirect detectors for performance optimization of a digital mammographic detector for dual energy applications

3rd International Conference on Mathematical Modeling in Physical Sciences

物理学;数学

Martini, N.^1 ; Koukou, V.^1 ; Kalyvas, N.^2 ; Sotiropoulou, P.^1 ; Michail, C.^2 ; Valais, I.^2 ; Bakas, A.^3 ; Kandarakis, I.^2 ; Nikiforidis, G.^1 ; Fountos, G.^2

Department of Medical Physics, Medical School, University of Patras, Patras

265 00, Greece^1

Department of Biomedical Engineering, Technological Educational Institute of Athens, Egaleo, Athens

122 10, Greece^2

Department of Medical Radiologic Technology, Technological Educational Institute of Athens, Egaleo, Athens

122 10, Greece^3

关键词: CMOS photodetectors;    Contrast to noise ratio;    Digital mammography;    Dual-energy imaging;    Indirect detection;    Microcalcifications;    Performance optimizations;    Phosphor materials;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/574/1/012075/pdf
DOI  :  10.1088/1742-6596/574/1/012075

来源: IOP

【 摘 要 】

Dual Energy imaging is a promising method for visualizing masses and microcalcifications in digital mammography. The advent of two X-ray energies (low and high) requires a suitable detector. The scope of this work is to determine optimum detector parameters for dual energy applications. The detector was modeled through the linear cascaded (LCS) theory. It was assumed that a phosphor material was coupled to a CMOS photodetector (indirect detection). The pixel size was 22.5 μm. The phosphor thickness was allowed to vary between 20mg/cm2and 160mg/cm2The phosphor materials examined where Gd2O2S:Tb and Gd2O2S:Eu. Two Tungsten (W) anode X-ray spectra at 35 kV (filtered with 100 μm Palladium (Pd)) and 70 kV (filtered with 800 pm Ytterbium (Yb)), corresponding to low and high energy respectively, were considered to be incident on the detector. For each combination the contrast- to-noise ratio (CNR) and the detector optical gain (DOG), showing the sensitivity of the detector, were calculated. The 40 mg/cm2and 70 mg/cm2Gd2O2S:Tb exhibited the higher DOG values for the low and high energy correspondingly. Higher CNR between microcalcification and mammary gland exhibited the 70mg/cm2and the 100mg/cm2Gd2O2S:Tb for the low and the high energy correspondingly.