Spectral and spatial resolution of semiconductor detectors in medical X- and gamma ray imaging

Heismann, Björn J.; Henseler, Debora; Niederloehner, D.; Hackenschmied, P.; Straßburg, M.; Janssen, Stijn; Wirth, Stéfan

doi:10.1109/nssmic.2008.4775129

Cited by 7 publications

(5 citation statements)

References 20 publications

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“…Other applications, e.g. medical imaging (Computed Tomography), need the capability to detect a photon flux of more than 1e9 photons/secmm 2 [14][15][16]. Such a detector has not been realised so far, because of the "polarization" effect, a reduction of the electric field strength inside the detector [8,17].…”

Section: Introductionmentioning

confidence: 99%

CdTe/CZT under high flux irradiation

Straßburg¹,

Schroeter²,

Hackenschmied³

2011

J. Inst.

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Direct converting quantum counting detectors based on cadmium telluride and cadmium zinc telluride have been investigated with respect to their properties under intense X-ray irradiation. To derive a detailed picture of the performance of such detectors, the influence of the electric field, the detector thickness, the temperature and the intensity of the X-ray irradiation was studied. The results are discussed in terms of the "polarization" phenomenon, a reduction of the electric field strength inside the detector due to immobile charge carriers accumulating during irradiation. Furthermore, the impact of Te-inclusions and -precipitates is presented.

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Section: Introductionmentioning

confidence: 99%

CdTe/CZT under high flux irradiation

Straßburg¹,

Schroeter²,

Hackenschmied³

2011

J. Inst.

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“…We perform a Monte-Carlo (MC) simulation of the noise transfer with the following steps, see also [5]:…”

Section: Simulationmentioning

confidence: 99%

“…For typical CT projections of bone and water attenuating cross-sections (Fig. 2), the SNR of the reconstructed coefficients is calculated by a Monte Carlo (MC) method established in [5]. …”

Section: Introductionmentioning

confidence: 99%

SNR performance comparison of dual-layer detector and dual-kVp spectral CT

Heismann

Wirth

2007

2007 IEEE Nuclear Science Symposium Conference Record

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-Tube-based dual-kVp and detector-based duallayer sandwich detector CT systems can be used to generate spectral CT data. We investigate the influence of their energy weighting functions on the performance of reconstructed base material coefficient images and projections. A Monte-Carlo (MC) simulation of the noise propagation for typical water and bone CT projections is used. We find a large difference in the SNR of the reconstructed coefficient projections. Dual-kVp scanning methods yield a factor of 2 better SNR in the coefficient projections than dual-layer detector based CT. This can be explained by the degree of overlap of the weighting functions, especially for low-energy X-ray quanta.

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“…Photon-counting detectors (PCDs), which can distinguish the energy of incident photons, can be used to obtain spectral information with threshold scanning (Katsuyuki and Iwanczyk 2013). However, the obtained spectra display severe distortions because of the complex effects in the detection process, including charge sharing (Kalemci and Matteson 2002, Tlustos et al 2004, Iwanczyk et al 2009, photon escaping (Shikhaliev et al 2009, Koenig et al 2011, pulse pileup (Heismann et al 2008, Taguchi et al 2011, Ballabriga et al 2016, and detector polarization (Siffert et al 1976), among others. These distortions can impose negative effects on the image quality and the accuracy of subsequent processing (Cammin et al 2012, Ding andMolloi 2012).…”

Section: Introductionmentioning

confidence: 99%

Spectrum reconstruction method based on the detector response model calibrated by x-ray fluorescence

Chen

2017

Phys. Med. Biol.

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Accurate estimation of distortion-free spectra is important but difficult in various applications, especially for spectral computed tomography. Two key problems must be solved to reconstruct the incident spectrum. One is the acquisition of the detector energy response. It can be calculated by Monte Carlo simulation, which requires detailed modeling of the detector system and a high computational power. It can also be acquired by establishing a parametric response model and be calibrated using monochromatic x-ray sources, such as synchrotron sources or radioactive isotopes. However, these monochromatic sources are difficult to obtain. Inspired by x-ray fluorescence (XRF) spectrum modeling, we propose a feasible method to obtain the detector energy response based on an optimized parametric model for CdZnTe or CdTe detectors. The other key problem is the reconstruction of the incident spectrum with the detector response. Directly obtaining an accurate solution from noisy data is difficult because the reconstruction problem is severely ill-posed. Different from the existing spectrum stripping method, a maximum likelihood-expectation maximization iterative algorithm is developed based on the Poisson noise model of the system. Simulation and experiment results show that our method is effective for spectrum reconstruction and markedly increases the accuracy of XRF spectra compared with the spectrum stripping method. The applicability of the proposed method is discussed, and promising results are presented.

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Spectral and spatial resolution of semiconductor detectors in medical X- and gamma ray imaging

Cited by 7 publications

References 20 publications

CdTe/CZT under high flux irradiation

CdTe/CZT under high flux irradiation

SNR performance comparison of dual-layer detector and dual-kVp spectral CT

Spectrum reconstruction method based on the detector response model calibrated by x-ray fluorescence

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