A novel method for contrast-to-noise ratio (CNR) evaluation of digital mammography detectors

Baldelli, Paola; Phelan, Niamh; Egan, Gillian

doi:10.1007/s00330-009-1409-3

Cited by 24 publications

(20 citation statements)

References 11 publications

(20 reference statements)

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“…In order to assess the uniformity of the CNR across the detector area, a figure of merit (CN R uni ) was evaluate following (Baldelli et al 2009):…”

Section: Contrast-to-noise Ratiomentioning

confidence: 99%

Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging

Esposito

Anaxagoras²,

Konstantinidis

et al. 2014

Phys. Med. Biol.

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Abstract:Recently CMOS Active Pixels Sensors (APSs) have become a valuable alternative to amorphous Silicon and Selenium Flat Panel Imagers (FPIs) in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Nonuniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uniformity and regional variations of a wafer scale stitched CMOS APS. For the first time a per-pixel analysis of the electro-optical performance of a wafer CMOS APS is presented, to address inhomogeneity issues arising from the stitching techniques used to manufacture wafer scale sensors. A complete model of the signal generation in the pixel array has been provided and proved capable of accounting for noise and gain variations across the pixel array. This novel analysis leads to readout noise and conversion gain being evaluated at pixel level, stitching block level and in regions of interest, resulting in a coefficient of variation ≤ 1.9%. The uniformity of the image quality performance has been further investigated in a typical X-ray application, i.e. mammography, showing a uniformity in terms of CNR among the highest when compared with mammography detectors commonly used in clinical practise. Finally, in order to compare the CONFIDENTIAL -FOR REVIEW ONLY PMB-100279.R1detection capability of this novel APS with the currently used technology (i.e. FPIs), theoretical evaluation of the Detection Quantum Efficiency (DQE) at zero-frequency has been performed, resulting in a higher DQE for this detector compared to FPIs. Optical characterization, X-ray contrast measurements and theoretical DQE evaluation suggest that a trade off can be found between the need of a large imaging area and the requirement of a uniform imaging performance, making the DynAMITe large area CMOS APS suitable for a range of bio-medical applications. in bio-medical imaging applications. CMOS APSs can now be scaled up to the standard 20 cm diameter wafer size by means of a reticle stitching block process. However despite wafer scale CMOS APS being monolithic, sources of non-uniformity of response and regional variations can persist representing a significant challenge for wafer scale sensor response. Non-uniformity of stitched sensors can arise from a number of factors related to the manufacturing process, including variation of amplification, variation between readout components, wafer defects and process variations across the wafer due to manufacturing processes. This paper reports on an investigation into the spatial non-uni...

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“…In order to assess the uniformity of the CNR across the detector area, a figure of merit (CN R uni ) was evaluate following (Baldelli et al 2009):…”

Section: Contrast-to-noise Ratiomentioning

confidence: 99%

Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging

Esposito

Anaxagoras²,

Konstantinidis

et al. 2014

Phys. Med. Biol.

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show abstract

“…Measurements were performed on axial and coronal reformatted images for all 50 patients. The baseline image quality was obtained as the mean CNR value, with CNR computed using the following equation 7 :…”

Section: Routine Temporal Bone Ct Clinical Image Quality Referencementioning

confidence: 99%

Radiation Dose Reduction in Temporal Bone CT with Iterative Reconstruction Technique

Niu

Mehta²,

Zhang³

et al. 2012

AJNR Am J Neuroradiol

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“…A qualidade de imagem em mamografia, como mostrado anteriormente, é afetada pela forma, tamanho e propriedades de absorção de raios X do tecido mamário, além da qualidade do feixe de raios X, da penumbra geométrica e das propriedades de contraste, resolução espacial e ruído do sistema de detecção (Toroi et al, 2007;Baldelli et al, 2009). …”

Section: Qualidade De Imagemunclassified

“…Para alguns detectores digitais, há uma relação linear entre a dose e o quadrado da CNR, por isso a CNR é um parâmetro amplamente usado para avaliar qualidade de imagem em mamografia (Baldelli et al, 2009). …”

Section: Qualidade De Imagemunclassified

“…Essa definição foi adotada como uma medida de controle de qualidade nas diretrizes européias para garantia de qualidade em triagem e diagnóstico de câncer de mama (Perry et al, 2006). A CNR é útil para testes de controle de qualidade pois pode ser monitorada no tempo (Baldelli et al, 2009). Samei et al (2005) afirmam que uma imagem digital de maior CNR oferece maior qualidade de imagem.…”

Section: Ruídounclassified

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Estudo experimental da otimização em sistemas de mamografia digital CR e DR

Perez

Poletti²,

Tomal³

et al.

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A novel method for contrast-to-noise ratio (CNR) evaluation of digital mammography detectors

Cited by 24 publications

References 11 publications

Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging

Performance of a novel wafer scale CMOS active pixel sensor for bio-medical imaging

Radiation Dose Reduction in Temporal Bone CT with Iterative Reconstruction Technique

Estudo experimental da otimização em sistemas de mamografia digital CR e DR

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