Signal transport in Computed Tomography detectors

Heismann, Björn J.; Bätz, Lothar; Pham-Gia, K.; Metzger, W.; Niederlöhner, D.; Wirth, Stéfan

doi:10.1016/j.nima.2008.03.018

Cited by 12 publications

(11 citation statements)

References 3 publications

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“…[13], [16]. Verfication measurements show that the simulation model results fit very well to spatially resolved light sensitivity and MTF measurements of CT detectors.…”

Section: Methodsmentioning

confidence: 74%

“…Its slight inclination is again due to the increase of the interaction depth with input energy. The overall absorption probability of the quanta is reduced with increasing input energy E. The low energy output events including Compton and Rayleigh scatter depositions are not shown, see [16] for a more detailed discussion of these.…”

Section: Resultsmentioning

confidence: 99%

“…For integrating indirect conversion detectors it has been shown [16], that the output signal variance increase leads to a Poisson excess noise. Following the work by Rabbani et al [23], a formula for the noise amplification has been established:…”

Section: Resultsmentioning

confidence: 99%

“…The X-ray energxy is converted into light photons. The energy conversion rate is around 13% [16]. Secondary light photon transport takes place.…”

Section: Methodsmentioning

confidence: 99%

“…1. For X-ray applications, a generalization to arbitrary input energies E is helpful, [16]. The Detector Response Function (DRF) D (i,k) (E, E ) yields a probability density to measure an incoming quantum of energy E as the output energy E .…”

Section: Theorymentioning

confidence: 99%

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

Heismann

Henseler

Niederloehner

et al. 2008

2008 IEEE Nuclear Science Symposium Conference Record

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Abstract-In X-and gamma ray based medical systems, detector performance is a key driver for diagnostic quality. Over the last years and decades, indirect conversion scintillator detectors have become the standard for many medical applications including X-ray Radiography, Computed Tomography and SPECT. Recently, direct conversion semiconductor detectors based on CdTe and CdZnTe (CZT) have come into focus, as they might offer improved or additional performance for specific applications. In this paper we use generic physical models to compare the spatial and spectral resolution of both detector types. The spatial resolution is quantified by the Modulation Transfer Function (MTF). We find that the direct conversion of quanta leads to an approximately sinc-like MTF. In comparison, the MTF of a pixelized scintillator detector shows a mid-frequency drop due to optical signal cross-talk.The spectral resolution of both detector types is described by the Detector Response Function (DRF). It yields the probability density D(E, E ) to measure an incoming quantum of energy E as the output energy E . As a general result we find that fluorescence X-ray cross-talk on one hand and charge sharing and optical cross-talk on the other hand significantly influence the DRF in both detector types. We compare the two detector types in a Computed Tomography application. For an integrating scintillator detector, a Poisson excess noise is observed and quantified. For a counting semiconductor detector, we describe the signficant low-energy shift in D(E, E ). The weighting functions of a two bin counting detctor are analyzed and compared to tube-based approaches. The results are summarized to show the trade-off between spectral and spatial resolution in medical imaging with direct conversion detectors.

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“…[13], [16]. Verfication measurements show that the simulation model results fit very well to spatially resolved light sensitivity and MTF measurements of CT detectors.…”

Section: Methodsmentioning

confidence: 74%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…The X-ray energxy is converted into light photons. The energy conversion rate is around 13% [16]. Secondary light photon transport takes place.…”

Section: Methodsmentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

See 3 more Smart Citations

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

Heismann

Henseler

Niederloehner

et al. 2008

2008 IEEE Nuclear Science Symposium Conference Record

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Application of Dual-target Computed Tomography for Material Decomposition of Low-Z Materials

Mikuláček,

Zemek,

Štarha

et al. 2024

J Nondestruct Eval

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The extension of conventional computed tomography known as spectral computed tomography involves utilizing the variations in X-ray attenuation, driven by spectral and material dependencies. This technique enables the virtual decomposition of scanned objects, revealing their elemental constituents. The resultant images provide quantitative information, such as material concentration within the scanned volume. Enhancements in results are achievable through methods that capitalize on the strong correlation among decomposed images, effectively minimizing noise and artifacts. The Rigaku nano3DX submicron tomograph uses a dual-target source, which allows the generation of two distinct X-ray spectra through different target materials. This configuration holds promise for high-resolution applications in spectral tomography, particularly for low-Z materials, where it offers high contrast in the acquired images. The potential of this setup in the context of spectral computed tomography is explored in this contribution, delving into its applications for materials characterized by low atomic numbers.

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Photon counting CT: Effects of dynamic beam attenuator on image quality

Atak

Shikhaliev

2017

Nuclear Instruments and Methods in Physics Research Section A:

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Signal transport in Computed Tomography detectors

Cited by 12 publications

References 3 publications

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

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

Application of Dual-target Computed Tomography for Material Decomposition of Low-Z Materials

Photon counting CT: Effects of dynamic beam attenuator on image quality

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