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Experimental comparison of noise and resolution for 2 k and 4 k storage phosphor radiography systems
Author(s) -
Flynn Michael J.,
Samei Ehsan
Publication year - 1999
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 - 10.1118/1.598656
Subject(s) - detective quantum efficiency , optics , optical transfer function , digital radiography , computed radiography , phosphor , noise (video) , image quality , materials science , radiography , physics , nuclear medicine , optoelectronics , image (mathematics) , computer science , medicine , artificial intelligence , nuclear physics
The purpose of this study was to compare the image quality for a digital storage phosphor system using 1760×2140 ( 2 k ) and 3520×4280 ( 4 k ) image arrays. Measurements were made on a chest radiography system (Fuji FCR‐9501) with special provisions to be operated in both 2 k (standard) and 4 k (HQ) modes. Presampled modulation transfer functions (MTF) were measured using an edge method. Noise power spectra (NPS) were determined for different input exposures by two‐dimensional Fourier analysis. These measures along with exposure measurements and an x‐ray spectral model were used to determine the frequency‐dependent detective quantum efficiency DQE ( f ) of the system for the 4 k and the 2 k modes. The magnitude of the NPS for the 4 k mode was about 1/2 that of the 2 k mode. A MTF value of 0.5 was found at 1.25 cycles/mm for the 4 k system and 1.50 cycles/mm for the 2 k system. The 4 k images had an extended MTF of 0.1 at 4.5 cycles/mm in the plate‐scan direction. Overall, the DQE ( f ) of the 4 k mode was slightly better than that for the 2 k mode by about 0.02 due primarily to its better noise characteristics.