Schematic of MAF showing locations of fiber-optic plates (FOP), fiber-optic taper, light image intensifier (LII), and CsI(Tl) input phosphor.
MAF in deployed position in front of a FPD with a custom-made detector changer on a C-arm gantry to facilitate switching between detectors.
Experimental setup showing location of head phantom for scatter measurements.
Measured scatter fraction as a function of lead disc size for two different air-gaps. The intercept on the y-axis represents the scatter fraction without the perturbation of the disc.
Scatter and focal spot MTFs.
Measured MTF for the MAF and the FPD.
Measured NNPS for the MAF (a) and the FPD (b) for different detector exposures.
Calculated DQE for the MAF and the FPD for exposures of 39.3 and 44.5 μR, respectively.
GMTFs for the MAF showing the effect of the choice of the focal spot size. Three different focal spots were used with a magnification factor of 1.20 and zero scatter fraction.
GDQEs for the MAF showing the effect of the choice of the focal spot size. Three different focal spots with a magnification factor of 1.20 and zero scatter fraction.
GMTF comparisons for the MAF and the FPD. Small and large focal spot with a scatter fraction of 0.33 and a magnification factor of 1.20.
GDQE comparisons for the MAF and the FPD. Small and large focal spot with a scatter fraction of 0.33 and a magnification factor of 1.20.
Images of a coronary stent with 100 μm struts were taken with the MAF using identical techniques parameters (RQA 5 spectrum with about 40 μR per frame detector entrance exposure and geometric magnification of 1.2) with three different focal spots. The arrow in each image shows the location for the line profiles shown in Fig. 14 .
Comparison of line profiles taken from the same locations in the stent images for the small and large focal spots shown in Fig. 13 . (The location of the line profiles is shown by the lines with arrows in Fig. 13 .) A total of seven different peaks indicated by the arrows in this figure were identified to calculate contrast.
Article metrics loading...
Full text loading...