&lt;title&gt;Signal, noise, and detective quantum efficiency in CCD-based x-ray imaging systems for use in mammography&lt;/title&gt;

Roehrig, Hans; Fajardo, Laurie L.; Yu, Tong; Schempp, W. V.

doi:10.1117/12.174269

Cited by 41 publications

(14 citation statements)

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“…Moreover they cut the over all x-ray flux with about a factor 2, something that is undesirable in photon starved applications. For mammography in particular careful evaluations of the DQE have been made [14,15] but we are aware of none that takes into account the energy spectrum; instead a mono-energetic beam is generally assumed.…”

Section: X-ray Energy Weightingmentioning

confidence: 99%

Dose-efficient system for digital mammography

et al. 2000

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We are developing a dose-efficient system for digital mammography. The system incorporates a refractive x-ray lens combined with a photon counting silicon sensor system. The system matches the digital nature of x-rays and maximum information can be extracted from the transmitted x-ray beam. The photon counting sensor system opens the possibility to weight each photon according to its information content. High-energy photons with little contrast information can be weighted low while low energy photons are weighted high. At the same time, using the refractive x-ray lens, the incident x-ray spectrum can be tuned to the optimum energy for a certain breast thickness. The performance of the system is expected to be close to the theoretical limit in terms of dose efficiency and is entirely limited by quantum noise. Since the standard use of the term DQE does not take into account the incident x-ray energy spectrum, scattered x-rays or the difference in information content from low to high-energy photons an alternative measure of performance is used. We refer to this measure as dose-efficiency and in this case the system is related to an ideal x-ray imaging system.

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Section: X-ray Energy Weightingmentioning

confidence: 99%

Dose-efficient system for digital mammography

et al. 2000

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“…The output data is 14 bits. Spatial non-uniformities of the CCD (spatial pixel noise) and vignetting of the lens are corrected for by flat fielding [13]. Fig.…”

Section: Data Acquisitionmentioning

confidence: 99%

Spatial noise and threshold contrasts in LCD displays

Roehrig

Krupiński

Chawla

et al. 2003

Medical Imaging 2003: Image Perception, Observer Performance, and Technology Assessment

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This paper presents the results of initial physical and psycho-physical evaluations of the noise of high resolution LCDs. 5 LCDs were involved, having 4 different pixel structures. Spatial as well as temporal noise was physically measured with the aid of a high-performance CCD camera. Human contrast sensitivity in the presence of spatial noise was determined psycho-physically using periodic stimuli (square-wave patterns) as well as aperiodic stimuli (squares). For the measurements of the human contrast sensitivity, all LCDs were calibrated to the DICOM 14 Grayscale Standard Display Function (GSDF). The results demonstrate that spatial noise is the dominant noise in all LCDs, while temporal noise is insignificant and plays only a minor part. The magnitude of spatial noise of LCDs is in the range between that of CRTs with a P104 and that of CRTs with a P45. Of particular importance with respect to LCD noise is the contribution of the pixel structure to the Noise Power Spectrum, which shows up as sharp spikes at spatial frequencies beyond the LCDs' Nyquist frequency. The paper does not offer any clues about the importance of these spikes on the human contrast sensitivity.

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“…This result indicates a higher signal-to-noise ratio or better DQE for system two in close correlation with the measurements on DQE reported elsewhere. 3 It is clear that the use of a contrast-detail phantom such as the CDMAM-phantom in IQC can provide quantitative information on the signal-to-noise ratio of digital imaging systems. Detection of an object with a particular diameter and thickness would indicate a particular show images of a particular section of the phantom taken with system two and system one, respectively, at the exact same exposure setting (2 plates, 27 kV, 500 mR).…”

Section: Acr-accreditation Phantommentioning

confidence: 99%

Image quality control for digital mammographic systems: Initial experience and outlook

Roehrig

Krupiński

1995

J Digit Imaging

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This report presents (1) a broad topical review anda tutorial of the possibilities for image quality control (IQC) with digita| systems, and (2) results and initial experience for IQC with two commercial digital imaging systems, but with limited discussion on any particular method. Digital imaging systems used for mammographically guided digital stereotactic breast biopsy were evaluated extensively at the University of Arizona. Measurements were made of linearity, sensitivity, signal-to-noise ratio, and square-wave modulation. Images of phantoms such as the American College of Radiology Accreditation Phantom and the contrast detail mammography Phantom were evaluated as well as images of the x-ray source's focal spot. The evaluation also included the cathode ray tubes for the imaging systems. The data collected show that digital imaging systems have an important advantage over film-screen systems because they provide a digital signal as output that can be used for quantitative analysis. Asa result, IQC can become a much more quantitative discipline than presently practiced, providing more information on the imaging systems under evaluation, and providing better control over their properties during actual operation.

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<title>Signal, noise, and detective quantum efficiency in CCD-based x-ray imaging systems for use in mammography</title>

Cited by 41 publications

References 0 publications

Dose-efficient system for digital mammography

Dose-efficient system for digital mammography

Spatial noise and threshold contrasts in LCD displays

Image quality control for digital mammographic systems: Initial experience and outlook

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