&lt;title&gt;Characterization of a full-field digital mammography detector based on direct x-ray conversion in selenium&lt;/title&gt;

Yorker, Jeffrey G.; Jeromin, Lothar S.; Lee, Denny L. Y.; Palecki, Eugene F.; Golden, Kelly P.; Jing, Zhenxue

doi:10.1117/12.465568

Cited by 45 publications

(35 citation statements)

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“…The key factor has been the strong development of detector technology that enables to maintain high enough spatial and contrast resolution as well as adequate quantum efficiency with low noise level. Current digital detector technologies in screening mammography include charge-coupled device (CCD) and indirect and direct flat panel detectors [1]- [4]. Among others, CMOS technology and photon counting technology are under development [5].…”

Section: Introductionmentioning

confidence: 99%

Physical characteristics of a clinical prototype for full-field digital mamography with an a-Se flat-panel detector

et al. 2003

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The purpose of this study was to evaluate physical characteristics of a clinical prototype for full-field digital mammography (FFDM) with an amorphous selenium (a-Se) flat-panel detector (FPD) and to compare these results with the currently available systems for FFDM. The effective FPD area consists of 2816 x 2016 pixel matrix having a pixel pitch of 85µm. This yields to theoretical maximum spatial frequency of ~5.9lp/mm. The basic performance of Instrumentarium clinical prototype direct mammography system has been assessed on the basis of measured response curve, the modulation transfer function (MTF), the noise power spectrum (NPS), the noise equivalent quanta (NEQ) and the detective quantum efficiency (DQE) in the clinical setting. The system shows a linear response curve over a dynamic range from 0.4 mR to 57 mR. The presampling MTF was found to be approximately 0.91, 0.72 and 0.50 at 2, 4 and 5.9 (Nyquist frequency) lp/mm. The NEQ is linearly related to the exposure starting from about 8 mR above which value the system can be considered noise quantum limited. The DQE, evaluated in clinical conditions (28kVp Mo-Mo spectrum hardened by 4cm of PMMA) is at close to zero spatial frequency approximately 69% at 46.4 mR and 61% at 8.3 mR. Below 8 mR the DQE(0) falls to 54.4%, 46% and 32.5% at 5.2, 3.0 and 1.4 mR respectively due to structured and electronic noise. The results of quantitative analysis demonstrate a high MTF as we expected due to direct conversion technology and a high DQE over the exposure range from 8 mR to 50 mR. The NEQ shows that the system can be considered noise quantum limited above 8 mR suggesting the exposure level that should be set in the clinical practice to ensure an adequate image quality.

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Section: Introductionmentioning

confidence: 99%

Physical characteristics of a clinical prototype for full-field digital mamography with an a-Se flat-panel detector

et al. 2003

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“…This statement is reflected by measurement results for two flat detectors, currently available with these two competing X-ray conversion materials. A detector based on a-Se/a-Si [35]featuring a pixel size of 70 μm which corresponds to a Nyquist frequency of 7.2 lp/mm-exhibits significantly higher DQE values over the whole spatial frequency range than a detector based on CsI/a-Si [36] which has a pixel size of 100 μm, corresponding to a Nyquist frequency of 5 lp/mm.…”

Section: Modulation Transfer Functionmentioning

confidence: 98%

Flat detectors and their clinical applications

Spahn

2005

Eur Radiol

111

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Diagnostic and interventional flat detector X-ray systems are penetrating the market in all application segments. First introduced in radiography and mammography, they have conquered cardiac and general angiography and are getting increasing attention in fluoroscopy. Two flat detector technologies prevail. The dominating method is based on an indirect X-ray conversion process, using cesium iodide scintillators. It offers considerable advantages in radiography, angiography and fluoroscopy. The other method employs a direct converter such as selenium which is particularly suitable for mammography. Both flat detector technologies are based on amorphous silicon active pixel matrices. Flat detectors facilitate the clinical workflow in radiographic rooms, foster improved image quality and provide the potential to reduce dose. This added value is based on their large dynamic range, their high sensitivity to X-rays and the instant availability of the image. Advanced image processing is instrumental in these improvements and expand the range of conventional diagnostic methods. In angiography and fluoroscopy the transition from image intensifiers to flat detectors is facilitated by ample advantages they offer, such as distortion-free images, excellent coarse contrast, large dynamic range and high X-ray sensitivity. These characteristics and their compatibility with strong magnetic fields are the basis for improved diagnostic methods and innovative interventional applications.

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“…The upper limit for the MTF is defined by assuming that the pixel aperture constitutes the only blur mechanism. It is quantitatively determined as a 0018-9499/$20.00 © 2006 IEEE function of spatial frequency and pixel aperture by the sinc function being defined as (1) which would describe the MTF of an ideal detector in one dimension related to an orientation in the spatial frequency plane parallel to one of the pixel lattice directions (2) The idealized MTF in diagonal direction [12] for a square pixel can be derived from the two-dimensional MTF (3) and is given by (4) The curves in this work are calculated up to the frequency where the sinc function equals zero. The values above the Nyquist frequency (i.e.…”

Section: Simulationsmentioning

confidence: 99%

“…D IGITAL mammography systems with detectors based on amorphous selenium are currently being introduced [1], [2]. Mammography systems with a detector combining a scintillator and a photodiode matrix are already in the market, e.g., the systems of G. E. Medical Systems [3] and Fischer [4].…”

Section: Introductionmentioning

confidence: 99%

Modulation transfer function of a selenium-based digital mammography system

Hoheisel

Bätz

Mertelmeier

et al. 2006

IEEE Trans. Nucl. Sci.

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Digital mammography systems with detectors based on amorphous selenium exhibit outstanding spatial resolution characterized by the modulation transfer function (MTF). We measured the detector behavior of the Siemens Mammomat Novation DR with 70 m pixel pitch and compared the results to analytical evaluations based on Monte Carlo simulations. Experimentally, the MTF of the mammography system is obtained from the images of a lead bar pattern or an edge phantom using different X-ray spectra. The simulations take into account all relevant X-ray interactions in the selenium layer. The resulting line-spread function is transformed to the MTF. Even at the Nyquist frequency (i.e., 7.14 mm 1 ), the measured MTF is well above 45% and thus fairly close to its theoretical limit (64%). The MTF shows a few percentage points of low-frequency drop, which can be explained in part by the presence of scattered radiation. The simulations allow the features observed to be explained. The detector investigated provides excellent spatial resolution and appears well suited for high-end mammography.

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<title>Characterization of a full-field digital mammography detector based on direct x-ray conversion in selenium</title>

Cited by 45 publications

References 0 publications

Physical characteristics of a clinical prototype for full-field digital mamography with an a-Se flat-panel detector

Physical characteristics of a clinical prototype for full-field digital mamography with an a-Se flat-panel detector

Flat detectors and their clinical applications

Modulation transfer function of a selenium-based digital mammography system

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