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Basic imaging properties of a computed radiographic system with photostimulable phosphors
Author(s) -
Fujita Hiroshi,
Ueda Katsuhiko,
Morishita Junji,
Fujikawa Tsuyoshi,
Ohtsuka Akiyoshi,
Sai Tokugi
Publication year - 1989
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 - 10.1118/1.596402
Subject(s) - optics , detective quantum efficiency , optical transfer function , materials science , computed radiography , aperture (computer memory) , noise (video) , digital radiography , photostimulated luminescence , phosphor , radiography , physics , image quality , luminescence , optoelectronics , artificial intelligence , computer science , acoustics , nuclear physics , image (mathematics)
We measured the characteristic curve, modulation transfer function (MTF), and the Wiener spectrum of a commercially available computed radiographic (CR) system with photostimulable phosphor plate (imaging plate, IP). The characteristic curve (system response) obtained by an inverse‐square x‐ray sensitometry showed a wide dynamic range (order of 10 3 in maximum). The slit technique was employed to determine the MTF's, such as IP MTF, presampling MTF including the unsharpness of the detector (IP) and the blurring effect of the sampling aperture, and laser‐printer MTF. It was found that the MTF of the standard type of IP was comparable to that of medium‐speed screen/film systems. The noticeable degradation of resolution in our CR system, however, occurred at the stage of image data sampling: the presampling MTF was inferior to the IP MTF due to the effect of the scattering and resultant spreading of the incident laser beam and the emitted luminescence. The noise was characterized by means of digital Wiener spectrum using uniformly exposed noise data. Exposure ranges could be separated into different sections depending upon the noise sources, such as quantum mottle at low exposure and system structure noise at high exposure.