Experimental and Theoretical Evaluation of a High Resolution CMOS Based Detector Under X-Ray Imaging Conditions

Michail, C.; Spyropoulou, V; Fountos, G.; Kalyvas, N.; Valais, I.; Kandarakis, I.; Panayiotakis, G.

doi:10.1109/tns.2010.2094206

Cited by 67 publications

(68 citation statements)

References 47 publications

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“…The filter thicknesses varied from 100-1000 m  for both energies. The surface dose, after filtration of the X-ray beams, was calculated according to equation (3) [12]. The total exposure is the sum of the low-and high-energy exposures.…”

Section: Methodsmentioning

confidence: 99%

Optimization of breast cancer detection in Dual Energy X-ray Mammography using a CMOS imaging detector

Koukou

Fountos

Martini

et al. 2015

J. Phys.: Conf. Ser.

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View the article online for updates and enhancements. Abstract. Dual energy mammography has the ability to improve the detection of microcalcifications leading to early diagnosis of breast cancer. In this simulation study, a prototype dual energy mammography system, using a CMOS based imaging detector with different X-ray spectra, was modeled. The device consists of a 33.91 mg/cm 2 Gd 2 O 2 S:Tb scintillator screen, placed in direct contact with the sensor, with a pixel size of 22.5 m  .Various filter materials and tube voltages of a Tungsten (W) anode for both the low and high energy were examined. The selection of the filters applied to W spectra was based on their Kedges (K-edge filtering). Hydroxyapatite (HAp) was used to simulate microcalcifications. Calcification signal-to-noise ratio (SNR tc ) was calculated for entrance surface dose within the acceptable levels of conventional mammography. Optimization was based on the maximization of SNR tc while minimizing the entrance dose. The best compromise between SNR tc value and dose was provided by a 35kVp X-ray spectrum with added beam filtration of 100μm Pd and a 70kVp Yb filtered spectrum of 800 m  for the low and high energy, respectively. Computer simulation results show that a SNR tc value of 3.6 can be achieved for a calcification size of 200 m  . Compared with previous studies, this method can improve detectability of microcalcifications.

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Section: Methodsmentioning

confidence: 99%

Optimization of breast cancer detection in Dual Energy X-ray Mammography using a CMOS imaging detector

Koukou

Fountos

Martini

et al. 2015

J. Phys.: Conf. Ser.

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show abstract

“…The Gd 2 O 2 S:Pr,Ce,F scintillating screens were manually coupled to an optical readout device including a CMOS Remote RadEye HR photodiode pixel array [9,12]. The CMOS photodiode array consists of 1200 × 1600 pixels with 22.5 m pixel spacing.…”

Section: Cmos Sensormentioning

confidence: 99%

“…However, in the present study, a value of 21627 photons × Gy −1 × mm −2 was calculated from direct X-ray spectra measurements with a portable Amptek XR-100T spectrometer and the extracted ESAK values were validated against direct measurements with a Victoreen 4000M+ dosimeter [12]. Accordingly, (3) was used for calculations; however, an alternative term was employed, namely, Image Quality Figure of Merit (IQFOM), due to the difference in the values proposed by the IEC protocol [13].…”

Section: Detective Quantum Efficiency (Dqe) and Image Quality Figure mentioning

confidence: 99%

Image Quality Assessment of a CMOS/Gd₂O₂S:Pr,Ce,F X-Ray Sensor

Michail

2015

Journal of Sensors

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The aim of the present study was to examine the image quality performance of a CMOS digital imaging optical sensor coupled to custom made gadolinium oxysulfide powder scintillators, doped with praseodymium, cerium, and fluorine (Gd 2 O 2 S:Pr,Ce,F). The screens, with coating thicknesses 35.7 and 71.2 mg/cm 2 , were prepared in our laboratory from Gd 2 O 2 S:Pr,Ce,F powder (Phosphor Technology, Ltd.) by sedimentation on silica substrates and were placed in direct contact with the optical sensor. Image quality was determined through single index (information capacity, IC) and spatial frequency dependent parameters, by assessing the Modulation Transfer Function (MTF) and the Normalized Noise Power Spectrum (NNPS). The MTF was measured using the slanted-edge method. The CMOS sensor/Gd 2 O 2 S:Pr,Ce,F screens combinations were irradiated under the RQA-5 (IEC 62220-1) beam quality. The detector response function was linear for the exposure range under investigation. Under the general radiography conditions, both Gd 2 O 2 S:Pr,Ce,F screen/CMOS combinations exhibited moderate imaging properties, in terms of IC, with previously published scintillators, such as CsI:Tl, Gd 2 O 2 S:Tb, and Gd 2 O 2 S:Eu.

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“…For the high-energy images, a copper (Cu) filter of 1000μm thickness was placed in the beam at 70kVp. The detection system consisted of a terbium-activated gadolinium oxisulfide (Gd 2 O 2 S:Tb) phosphor screen (Min-R 2190 with a mass thickness of 33.91mg/cm 2 ) coupled to a CMOS photodiode pixel array (Remote RadEye HR) [9,10]. The CMOS photodiode array has a format of 1200x1600 pixels with a pitch of 22.5μm.…”

Section: Ln De Ln He Wln Le  mentioning

confidence: 99%

PVAL breast phantom for dual energy calcification detection

Koukou

Martini

Velissarakos

et al. 2015

J. Phys.: Conf. Ser.

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Experimental and Theoretical Evaluation of a High Resolution CMOS Based Detector Under X-Ray Imaging Conditions

Cited by 67 publications

References 47 publications

Optimization of breast cancer detection in Dual Energy X-ray Mammography using a CMOS imaging detector

Optimization of breast cancer detection in Dual Energy X-ray Mammography using a CMOS imaging detector

Image Quality Assessment of a CMOS/Gd₂O₂S:Pr,Ce,F X-Ray Sensor

PVAL breast phantom for dual energy calcification detection

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Experimental and Theoretical Evaluation of a High Resolution CMOS Based Detector Under X-Ray Imaging Conditions

Cited by 67 publications

References 47 publications

Optimization of breast cancer detection in Dual Energy X-ray Mammography using a CMOS imaging detector

Optimization of breast cancer detection in Dual Energy X-ray Mammography using a CMOS imaging detector

Image Quality Assessment of a CMOS/Gd2O2S:Pr,Ce,F X-Ray Sensor

PVAL breast phantom for dual energy calcification detection

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Product

Resources

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Image Quality Assessment of a CMOS/Gd₂O₂S:Pr,Ce,F X-Ray Sensor