Study of CdTe and CdZnTe detectors for X-ray computed tomography

Ricq, Stéphane; Glasser, F.; Garcin, Michel

doi:10.1016/s0168-9002(00)00922-0

Cited by 22 publications

(9 citation statements)

References 13 publications

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“…While the afterglow curve for the GOS based detector fulfills this specification, the photocurrent decay of all CZT pixels is slower than required. The latter observation complies with previous findings on afterglow of Cd(Zn)Te [33], [34] . Thus, temporal lag of CZT sensors will have to be reduced in the future if integrating-mode CT detectors are equipped with this kind of direct conversion material.…”

Section: A Afterglow Characteristicssupporting

confidence: 93%

Status of Direct Conversion Detectors for Medical Imaging With X-Rays

Overdick

Bäumer

Engel

et al. 2009

IEEE Trans. Nucl. Sci.

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Imaging detectors for medical X-ray and computed tomography (CT) applications have undergone many improvements and technology changes over time. But most (dynamic) detectors sold in this field still rely on indirect conversion, using scintillators and photodiodes to convert the X-ray quanta ultimately into electrical signals. Direct conversion detectors promise very high spatial resolution and high signal-to-noise ratios. Some direct conversion materials may allow for counting or even energy resolving detection of the X-ray quanta. Based on this, for example spectrally resolving CT systems are becoming an interesting option for the next decade. This contribution highlights the requirements of advanced medical X-ray and CT imaging and reviews examples of status and progress in the field. The emphasis is on the direct conversion sensors for pixelated detectors, but considerations on read-out concepts and on associated challenges such as interconnects will also be presented. Finally, the most burning issues, such as count rate limitations and polarization effects, will be discussed from an application point of view.

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Section: A Afterglow Characteristicssupporting

confidence: 93%

Status of Direct Conversion Detectors for Medical Imaging With X-Rays

Overdick

Bäumer

Engel

et al. 2009

IEEE Trans. Nucl. Sci.

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“…It has previously been reported that an increase in the concentration of cadmium vacancies occurs during electroless deposition [13] while other authors have proposed that the presence of chlorine is correlated with an increase in the concentration of cadmium interstitials (E C −0.56 eV) [37]. It is also well known that chlorine compensates cadmium vacancies in CdZnTe forming an A-centre (E V +0.12 eV) with the shallow chlorine donor, Cl Te (E C − 0.14 eV) [38][39][40].…”

Section: Fib and Tem Analysismentioning

confidence: 99%

A multi-technique characterization of electroless gold contacts on single crystal CdZnTe radiation detectors

Bell

Baker

Chen

et al. 2013

J. Phys. D: Appl. Phys.

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“…For example, only 5% of photon energy will be lost after a 100-keV photon is scattered by the Compton effect at 45 [34]. Then the actual received scatter that occurred in the interpolated voxel along the projection line and reaching detector can be obtained by (1)-(6), as shown below (7) The scatter to primary ratio of the detector at the energy can be obtained as follows: (8) where is the Compton scatter to primary ratio of detector at the energy , is number of detector elements, is the X-ray energy spectrum of a CT system in the projection line , and is the X-ray energy spectrum of a CT system in the projection line . By assuming the X-ray energy spectrum of different projection line is composed by the same basic spectrum with various total intensity which implies that , (8) becomes where is the blank scan (intensity without the presence of an object) in the projection line , and is the blank scan in the projection line .…”

Section: B Single Scatter Modelmentioning

confidence: 99%

A Single Scatter Model for X-ray CT Energy Spectrum Estimation and Polychromatic Reconstruction

Lee

Chen²

2015

IEEE Trans. Med. Imaging

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To improve the quantitative accuracy of linear attenuation coefficients measured by computed tomography (CT), we used a single scatter model to estimate the Compton scatter distribution and then a polychromatic image reconstruction algorithm, namely the iterative maximum-likelihood polychromatic algorithm for CT (IMPACT), was implemented to include scatter correction (SC). To perform the IMPACT, the X-ray spectra of a tube were estimated via an expectation-maximization (EM) algorithm with SC. To test the accuracy of the estimated spectra, the projection images of cubic phantoms containing different depths of polymethylmethacrylate (PMMA) were acquired. The percentage of root mean square errors (%RMSE) of the measured transmission data and calculated transmission values were used to evaluate the accuracy of the estimated spectra. In addition, a hydroxylapatite (HA) phantom was used to study streak artifacts and evaluate the accuracy of the linear attenuation coefficients estimated using the IMPACT with SC. The %RMSE of the EM-with-SC estimated spectra were all lower than 1% and were also smaller than that without SC. The error in the quantification of the HA linear attenuation was only about 3% after SC. Our results showed that the quantitative accuracy of the linear attenuation coefficients measured with a cone beam CT was improved when the IMPACT with SC was used.

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Study of CdTe and CdZnTe detectors for X-ray computed tomography

Cited by 22 publications

References 13 publications

Status of Direct Conversion Detectors for Medical Imaging With X-Rays

Status of Direct Conversion Detectors for Medical Imaging With X-Rays

A multi-technique characterization of electroless gold contacts on single crystal CdZnTe radiation detectors

A Single Scatter Model for X-ray CT Energy Spectrum Estimation and Polychromatic Reconstruction

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