A digital full-filed mammography system using phase-contrast technique has been developed. The system consists of a dedicated mammography unit, a computed radiography unit with a sampling rate of ...43.75 microns, and a photothermographic printer with a printing rate of 25 microns for photothermographic film with the maximum optical density of 4.0. The sharpness of the output image is improved with an edge effect due to phase contrast and magnification. The image noise is reduced by an air-gap method with no bucky. In this paper, the image qualities of the phase-contrast mammography are described for full-filed mammography and spot-compression at 1.5x magnification.
Recent advances in the design of photostimulable phosphor (PSP) plates for computed radiography (CR) systems have made it possible to manufacture plates made of BaFI:Eu phosphor material in the ...cassette form. The image quality of this plate, six BaF(Br,I):Eu plates, and one BaFBr:Eu plate were evaluated in terms of presampling modulation transfer function (MTF), normalized Wiener spectra
(
WS
N
),
and detective quantum efficiency (DQE). Compared with the best-performing BaF(Br,I):Eu plate, the BaFI:Eu plate provided DQE that was higher, at spatial frequencies of 0.5, 1.0, and 2.0 cycles/mm, by 12% (21.8 versus 19.4), 13% (18.8 versus 16.7), and 11% (12.0 versus 10.8), respectively. Since presampling MTF values of the two plates were comparable, the BaFI:Eu plate’s higher DQE is attributable to total
WS
N
conversely being lower by 17%
8.65×10
−5
(
mm
2
)
versus
10.38×10
−5
(
mm
2
),
17%
5.85×10
−5
(
mm
2
)
versus
7.03×10
−5
(
mm
2
),
and 12%
2.82×10
−5
(
mm
2
)
versus
3.19×10
−5
(
mm
2
)
at the specified frequencies, respectively, primarily due to the contribution of x-ray quantum
WS
N
.
This jibes with the high x-ray absorption provided by the 27%-higher x-ray attenuation coefficients (7.54 versus 6.07, at 60 KeV) that BaFI offers over
BaF
(
Br
0.85
,
I
0.15
),
a result of the high atomic number of BaFI’s exclusively iodine halide content. The results were consistent with earlier studies of several of these same plates and indicate that BaFI:Eu is a promising avenue to lower image noise and higher overall CR system image quality.
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Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
We have developed a digital full-field phase contrast mammography (PCM) system. PCM system has several advantages comparing with current digital imaging system without PCM configuration, such as 1) ...improvement of structural depiction by phase contrast, 2) the highest image solution with 25 micron meters pixels, and 3) improvement of image quality performance due to the air gap effect and to its reduction of the magnified image to the object's actual size. We compared images from the PCM system with images from digital imaging system without PCM configuration in terms of physical characteristics, subjective evaluation of images of a custom-made phantom, and performance in clinical application. The PCM system proved superior to current digital imaging system without PCM configuration by all measures of evaluation.
Recent advances in the design of photostimulable phosphor (PSP) plates for computed radiography (CR) systems have made it possible to manufacture plates made of BaFI:Eu phosphor material in the ...cassette form. The image quality of this plate, six BaF(Br,I):Eu plates, and one BaFBr:Eu plate were evaluated in terms of presampling modulation transfer function (MTF), normalized Wiener spectra (WSN), and detective quantum efficiency (DQE). Compared with the best-performing BaF(Br,I):Eu plate, the BaFI:Eu plate provided DQE that was higher, at spatial frequencies of 0.5, 1.0, and 2.0 cycles/mm, by 12% (21.8 versus 19.4), 13% (18.8 versus 16.7), and 11% (12.0 versus 10.8), respectively. Since presampling MTF values of the two plates were comparable, the BaFI:Eu plate's higher DQE is attributable to total WSN conversely being lower by 17% 8.65 x 10(-5) (mm2) versus 10.38 x 10(-5) (mm2), 17% 5.85 x 10(-5) (mm2) versus 7.03 x 10(-5) (mm2), and 12% 2.82 x 10(-5) (mm2) versus 3.19 x 10(-5) (mm2) at the specified frequencies, respectively, primarily due to the contribution of x-ray quantum WSN. This jibes with the high x-ray absorption provided by the 27%-higher x-ray attenuation coefficients (7.54 versus 6.07, at 60 KeV) that BaFI offers over BaF(Br(0.85),I(0.15)), a result of the high atomic number of BaFI's exclusively iodine halide content. The results were consistent with earlier studies of several of these same plates and indicate that BaFI:Eu is a promising avenue to lower image noise and higher overall CR system image quality.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Abstract
The morphologies of sulfonated polystyrene-block-fluorinated polyisoprene (s-PS-b-f-PI) were studied as functions of different kinds of solvents and thermal annealing, using transmission ...electron microscope microscopy (TEM), small angle X-ray scattering (SAXS) and intermediate angle X-ray diffraction (IMAXD). The film of the block copolymer ionomer with an acid form sulfonated PS-b-fluorinated PI (sH-PS-b-f-PI), which was cast from anhydrous tetrahydrofuran (THF), developed a well-ordered cylindrical morphology of the f-PI domains in the sH-PS matrix. The morphology was explained by the solubility parameter and the Bjerrum length. The morphology changed to that of a no long-range ordered structure, through thermal annealing. The result was different from the usual behavior of uncharged diblock copolymers and could have been due to the ionic cluster formation. The solution casting films of the block copolymer ionomer with a cesium neutralized form (sCs-PS-b-f-PI) were obtained from the mixed solvent of THF/water (98/2, wt/wt) and DMSO. The ionic cluster formation in the film cast from the mixed solvent was hardly changed by annealing. The promotion of the ionic cluster formation by annealing was clearly observed in the film cast from DMSO. However, hindrance of microphase separation by the promotion of the ionic cluster formation was not confirmed in this study.
