Premium
X‐ray imaging with amorphous selenium: Detective quantum efficiency of photoconductive receptors for digital mammography
Author(s) -
Fahrig Rebecca,
Rowlands J. A.,
Yaffe Martin J.
Publication year - 1995
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597599
Subject(s) - detective quantum efficiency , x ray detector , optics , physics , quantum efficiency , photoconductivity , digital radiography , optoelectronics , image sensor , photoelectric effect , detector , photon , absorption (acoustics) , materials science , image quality , radiography , computer science , nuclear physics , image (mathematics) , artificial intelligence
Factors affecting the zero spatial frequency detective quantum efficiency of photoconductor‐based x‐ray detectors operating in the mammographic energy range are modeled for monoenergetic incident x rays. The problem is separated into two sections: the calculation of the x‐ray absorption and the Swank factor. X‐ray absorption in this energy range, for most practical photoconductors, is dominated by the photoelectric effect. The Swank factor has four components: fluorescence escape, stochastic variations in gain, variations of gain due to incomplete coupling of charge from the photoconductive layer to the detector electrode, and the nonlinear discharge arising from the field‐dependent x‐ray gain, an effect that is unique to photoconductors. Calculations are performed for selenium, which is currently the most technologically advanced photoconductor available for digital x‐ray imaging. For thicknesses of selenium exceeding 50 μm and for energies between 12 and 50 keV, the detective quantum efficiency of this photoconductor is found to exceed that of a conventional Gd 2 O 2 S‐based mammographic phosphor screen.