Vision 20/20: Single photon counting x‐ray detectors in medical imaging

Taguchi, Katsuyuki; Iwanczyk, Jan S.

doi:10.1118/1.4820371

Cited by 813 publications

(754 citation statements)

References 142 publications

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“…This phenomenon is known as "pulse pileup" and negatively affects image quality, Hounsfield unit accuracy, and material decomposition. 8 However, recent advances in PCD technology with high-speed application-specific integrated circuits and small pixel sizes have led to the development of PCDs resistant to pulse pileup at clinically routine CT tube currents. 15 Another PCD artifact is charge sharing, which occurs when the energy of an x-ray photon is distributed across multiple adjacent detector pixels, reducing the accuracy of the detected photon energy.…”

Section: Discussionmentioning

confidence: 99%

“…PCDs measure the number of detected x-ray photons (ie, photon count) and their photon energy. [6][7][8][9][10][11] These characteristics allow equal weighting of low-and high-energy photons and may therefore be useful for improving soft-tissue contrast in the brain. 8 In addition, the direct conversion and counting of individual photons provide a better estimate of the underlying photon statistics, which, in turn, may improve image quality by reducing image noise.…”

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confidence: 99%

“…8 In addition, the direct conversion and counting of individual photons provide a better estimate of the underlying photon statistics, which, in turn, may improve image quality by reducing image noise. 8,[12][13][14] We hypothesized that the combined effects of better contrast and reduced noise may lead to better overall GM-WM differentiation in brain PCD CT.…”

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confidence: 99%

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Photon-Counting CT of the Brain: In Vivo Human Results and Image-Quality Assessment

Pourmorteza

Symons

Reich

et al. 2017

AJNR Am J Neuroradiol

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Photon-Counting CT of the Brain: In Vivo Human Results and Image-Quality Assessment

Pourmorteza

Symons

Reich

et al. 2017

AJNR Am J Neuroradiol

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“…1 Due to the combination of direct x-ray detection in the high-Z semiconductor sensor and single photon counting electronics in each pixel of the ASIC, such detectors offer high detection efficiency (above 70% up to energies of 60 keV), high spatial resolution (below 100 lm), high maximum count rate capability (up to 10 9 counts/mm 2 /s), and good energy resolution (2-5 keV in an energy range from 5 to 140 keV). In the field of x-ray diffraction, HPC detectors proved to be a disruptive technology 2 both for scientific and industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Assessment of the spectral performance of hybrid photon counting x‐ray detectors

Trueb¹,

Zambon²,

Broennimann³

2017

Medical Physics

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Purpose: Hybrid Photon Counting (HPC) detectors profoundly improved x-ray diffraction experiments at third generation synchrotron facilities. Enabling the simultaneous measurement of x-ray intensities in multiple energy bins, they also have many potential applications in the field of medical imaging. A prerequisite for this is a clean spectral response. To quantify how efficiently HPC detectors are able to assign photons to the correct energy bin, a quantity called Spectral Efficiency (SE) is introduced. This figure of merit measures the number of x-rays with correctly assigned energy normalized to the number of incoming photons. Methods: A prototype HPC detector has been used to perform precision measurements of x-ray spectra at the BESSY synchrotron. The detector consists of a novel ASIC with pixels of 75 9 75 lm 2 size and a 750 lm thick CdTe sensor. The experimental data are complemented by the results of a Monte-Carlo (MC) simulation, which not only includes the physical detection process but also pulse pile-up at high photon fluxes. The spectra and the measured photon flux are used to infer the Spectral Efficiency. Results: In the energy range from 10 to 60 keV, both the Quantum Efficiency and the Spectral Efficiency were precisely measured and simulated. Good agreement between simulation and experiment has been achieved. For the small pixels of the prototype detector, a SE between 15% and 77% has been determined. The MC simulation is used to predict the SE for various pixel sizes at different photon fluxes. For a typical flux of 5•10 7 photons/mm 2 /s used in human Computed Tomography (CT), the highest SE is achieved for pixel sizes in the range between 150 9 150 lm 2 and 300 9 300 lm 2 . Conclusions: The Spectral Efficiency turns out to be a useful figure of merit to quantify the spectral performance of HPC detectors. It allows a quantitative comparison of detectors with different sensor and ASIC configurations over a broad range of x-ray energies and fluxes. The maximization of the SE is a prerequisite for a successful usage of HPC detectors in the field of medical imaging.

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“…Energy sensitive pixel detectors are finding applications in X-ray imaging [1,2]. These devices not only provide a high spatial resolution, but they are also capable of energy estimation at single photon level.…”

Section: Introductionmentioning

confidence: 99%

Prospects for spectral CT with Medipix detectors

Schioppa¹,

Visser²,

Koffeman³

2015

Proceedings of Technology and Instrumentation in Particle Physics 2014 — PoS(TIPP2014)

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In the development of X-ray Computed Tomography (CT) in medical imaging, one is working to implement spectral information. While keeping the dose level the same, or even lower, than in conventional systems, spectral CT offers the possibility to measure energy dependent features of different tissues that will allow the extraction of additional information about the patient, eventually leading to real color CT. Spectral CT can be achieved through the application of energy sensitive pixel detectors, such as Medipix-based semiconductor devices and by the implementation of reconstruction algorithms where the energy information is taken into account. In this paper, we present the latest results of our work on spectral CT with Medipix detectors and specifically on detector characterization and the development of algorithms that include energy information. Technology and Instrumentation in PoS(TIPP2014)246Prospects for spectral CT with Medipix detectors Enrico Jr. Schioppa (a) Bare readout pixel matrix.(b) ASIC bump-bonded to a silicon sensor.

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Vision 20/20: Single photon counting x‐ray detectors in medical imaging

Cited by 813 publications

References 142 publications

Photon-Counting CT of the Brain: In Vivo Human Results and Image-Quality Assessment

Photon-Counting CT of the Brain: In Vivo Human Results and Image-Quality Assessment

Assessment of the spectral performance of hybrid photon counting x‐ray detectors

Prospects for spectral CT with Medipix detectors

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