&lt;title&gt;Signal-to-noise performance in cesium iodide x-ray fluorescent screens&lt;/title&gt;

Hillen, Walter; Eckenbach, W.; Quadflieg, Peter; Zaengel, T.

doi:10.1117/12.43435

Cited by 39 publications

(21 citation statements)

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“…Also at these high frequencies, noise aliasing degrades the DQE by approximately 50%. Reabsorption causes a 20-25% degradation of the DQE over most non-zero frequencies, consistent with other works (Metz and Vyborny, 24 Hillen et al 20 ). The value of f K was obtained from a numerical estimate based on the CsI thickness and solid-angle considerations; however, the theoretical DQE result is insensitive to variations in f K between 0.6 and 1.0.…”

Section: Discussionsupporting

confidence: 87%

“…The term with the square brackets in the final form of this expression describes Swank noise for a thin transparent phosphor. 18 Rowlands and Taylor, 19 Hillen et al 20 and others have described the variance of the conversion gain as a function of energy for CsI which can be used in this calculation for a specific spectrum. While this description includes the variable conversion gain, it does not describe the spatial-frequency-dependent aspects of reabsorption.…”

Section: X-ray Spectral Effects and Swank Noisementioning

confidence: 99%

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<title>Cascaded models and the DQE of flat-panel imagers: noise aliasing, secondary quantum noise, and reabsorption</title>

Cunningham¹,

Yao²,

Subotic³

2002

SPIE Proceedings

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Theoretical models of the detective quantum efficiency (DQE) provide insight into fundamental performance limitations and standards to which particular systems can be compared. Over the past several years, cascaded models have been developed to describe the DQE of several flat panel detectors. This article summarizes the governing principles of cascaded models, and conditions that must be satisfied to prevent misuse. It is shown how to incorporate: a) poly-energetic x rays; b) Swank noise; c) the Lubberts effect; d) reabsorption of K x rays from photo-electric interactions; e) secondary quantum noise; and, f) noise aliasing.Cascaded models involve cascading theoretical expressions of the noise-power spectrum (NPS) through multiple stages. Most expressions involve two or three terms, requiring the manipulation of algebraic expressions consisting of hundreds of terms. This practical limitation is alleviated using MATLAB's Simulink programming environment and symbolic math manipulations. It is shown that even for an "indirect" detector, noise aliasing reduces the DQE by up to 50% at the cut-off frequency. Secondary quantum noise is generally a small effect, but reabsorption can reduce the DQE by 20-25% over a wide range of spatial frequencies.

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Section: Discussionsupporting

confidence: 87%

Section: X-ray Spectral Effects and Swank Noisementioning

confidence: 99%

<title>Cascaded models and the DQE of flat-panel imagers: noise aliasing, secondary quantum noise, and reabsorption</title>

Cunningham¹,

Yao²,

Subotic³

2002

SPIE Proceedings

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“…Each type includes several different values of layer thickness, and fitting these data with our model allowed the understanding of the difference in image quality between these two types of CsI layers, and testing of our model in the thickness dependence of MTF. (ii) Complete MTF, NPS and DQE(f) measurements were obtained for an experimental XRII 28 at different x-ray energies, both above and below the K-edges of CsI. Experimental data for two flat panel imagers were examined: (iii) Two sources of data on a mammographic imager 29,30 were used to represent data below the K-edges of the CsI and (iv) A radiographic imager 31 represented data above the K-edges of the CsI.…”

Section: Experimental Datamentioning

confidence: 99%

“…The two approaches are in essential agreement demonstrating the validity of the analytical approach. (b) Detective quantum efficiency of the 270 µm thick CsI layer obtained using an experimental XRII 28. The experimental data obtained at 32 keV is shown as circles, 38 keV as diamonds and 59.5 keV as squares.…”

mentioning

confidence: 99%

Effect of depth-dependent modulation transfer function and K-fluorescence reabsorption on the detective quantum efficiency of indirect-conversion flat-panel x-ray imaging systems using CsI

Rowlands

Zhao

2001

Medical Imaging 2001: Physics of Medical Imaging

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A theory of the imaging behavior of structured phosphor layers is developed based on linear analysis and Monte Carlo modeling and tested by comparison with experiments. The experiments include: modulation transfer function (MTF) measured as a function of spatial frequency f on CsI phosphor layers of different thicknesses and optical properties (e.g. presence or absence of reflective backing layer). These measurements on structured screens were used to establish phosphor parameters (e.g. absorption and scattering lengths). In addition, MTF(f), Wiener noise power spectra [NPS(f)] and detective quantum efficiency [DQE(f)] measurements were obtained from the literature for x-ray image intensifiers and indirect conversion flat panel detectors constructed using CsI layers. These results were compared with the theory using the previously established phosphor parameters. The effects of K-fluorescence and depth dependence of the MTF on DQE (i.e. Lubberts' effect) were investigated.

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“…Thus a mediating x-ray sensitive scintillator is necessary to convert the radiation to visible light. However, a degree of diffusion of the luminescent photns occurs in the scintillator layer as a consequence of which the modulation transfer function (MTF) deteriorates for the detected x-ray image [3].…”

Section: Introductionmentioning

confidence: 99%

Amorphous silicon pixel layers with cesium iodide converters for medical radiography

Tao

Goodman

Drewery

et al. 1994

IEEE Trans. Nucl. Sci.

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<title>Signal-to-noise performance in cesium iodide x-ray fluorescent screens</title>

Cited by 39 publications

References 0 publications

<title>Cascaded models and the DQE of flat-panel imagers: noise aliasing, secondary quantum noise, and reabsorption</title>

<title>Cascaded models and the DQE of flat-panel imagers: noise aliasing, secondary quantum noise, and reabsorption</title>

Effect of depth-dependent modulation transfer function and K-fluorescence reabsorption on the detective quantum efficiency of indirect-conversion flat-panel x-ray imaging systems using CsI

Amorphous silicon pixel layers with cesium iodide converters for medical radiography

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