Energy dependence of SNR and DQE for effective monoenergetic imaging in spectral CT

2018 ◽  
Author(s):  
Paurakh L. Rajbhandary ◽  
Norbert J. Pelc
Keyword(s):  
Energy Dependence ◽  
Spectral Ct ◽  
Monoenergetic Imaging

ENERGY DEPENDENCE OF THE POLARISATION IN ZERO-FIELD QUANTUM BEATS IN Hβ EMISSION

1979 ◽  
Vol 40 (C1) ◽  
pp. C1-335-C1-337 ◽  
Author(s):  
J. Carmeliet ◽  
J. C. Dehaes ◽  
W. Singer
Keyword(s):  
Energy Dependence ◽  
Quantum Beats ◽  
Zero Field

DEEP LEVELS' ACTIVATION ENERGY DEPENDENCE ON MEASUREMENT MODES

2019 ◽  
Author(s):  
Aleksey Bogachev ◽  
Vladimir Krylov
Keyword(s):  
Activation Energy ◽  
Gallium Arsenide ◽  
Energy Dependence ◽  
Deep Level ◽  
Deep Levels ◽  
Blocking Voltage

The results of an experiment to determine the activation energy of a deep level in a gallium arsenide mesastructure by capacitive relaxation spectroscopy of deep levels at various values of the blocking voltage are considered.

Fluctuations

2018 ◽  
Author(s):  
Richard Wigmans
Keyword(s):  
Energy Dependence ◽  
Energy Resolution ◽  
Practical Importance ◽  
Shower Particle ◽  
Formation Processes ◽  
Instrumental Effects ◽  
Important Type ◽  
High Energies ◽  
Different Types ◽  
Electromagnetic Component

The energy resolution, i.e. the precision with which the energy of a showering particle can be measured, is one of the most important characteristics of a calorimeter. This resolution is determined by fluctuations in the absorption and signal formation processes. In this chapter, the different types of fluctuations that may play a role are examined, and their relative practical importance is addressed. Sources of fluctuations include fluctuations in the number of signal quanta, sampling fluctuations, fluctuations in shower leakage, as well as a variety of instrumental effects. Since the energy dependence of the different types of fluctuations is not the same, different types of fluctuations may dominate the energy resolution at low and and at high energies. An important type of fluctuations is part of the non-compensation phenomena. It concerns fluctuations in the strength of the electromagnetic component of hadronic showers. The effects of these fluctuations, which typically dominate the energy resolution for hadron and jet detection, are examined in detail. In sampling calorimeters, one particular shower particle may sometimes have catastrophic effects on the calorimeter performance. Several examples of such cases are discussed.

scholarly journals A note on the relations between elastic and inelastic interactions and increasing ratio σel(s)/σtot(s) at the LHC

2019 ◽  
Vol 34 (32) ◽  
pp. 1950259 ◽  
Author(s):  
S. M. Troshin ◽  
N. E. Tyurin
Keyword(s):  
Elastic Scattering ◽  
Energy Dependence ◽  
Impact Parameter ◽  
Cross Sections ◽  
Parameter Dependence ◽  
Slope Parameter ◽  
Short Notice ◽  
Inelastic Interactions ◽  
The Impact ◽  
Mode A

We comment briefly on relations between the elastic and inelastic cross-sections valid for the shadow and reflective modes of the elastic scattering. Those are based on the unitarity arguments. It is shown that the redistribution of the probabilities of the elastic and inelastic interactions (the form of the inelastic overlap function becomes peripheral) under the reflective scattering mode can lead to increasing ratio of [Formula: see text] at the LHC energies. In the shadow scattering mode, the mechanism of this increase is a different one, since the impact parameter dependence of the inelastic interactions probability is central in this mode. A short notice is also given on the slope parameter and the leading contributions to its energy dependence in both modes.

scholarly journals Detection of Bone Marrow Edema in Patients with Osteoid Osteoma Using Three-Material Decomposition with Dual-Layer Spectral CT

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 953
Author(s):  
Florian T. Gassert ◽  
Johannes Hammel ◽  
Felix C. Hofmann ◽  
Jan Neumann ◽  
Claudio E. von Schacky ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Osteoid Osteoma ◽  
Bone Marrow Edema ◽  
Volume Fraction ◽  
Imaging Findings ◽  
Spectral Ct ◽  
Material Decomposition ◽  
Negative Imaging ◽  
Interreader Agreement ◽  
Marrow Edema

The aim of this study is to assess whether perifocal bone marrow edema (BME) in patients with osteoid osteoma (OO) can be accurately detected on dual-layer spectral CT (DLCT) with three-material decomposition. To that end, 18 patients with OO (25.33 ± 12.44 years; 7 females) were pairwise-matched with 18 patients (26.72 ± 9.65 years; 9 females) admitted for suspected pathologies other than OO in the same anatomic location but negative imaging findings. All patients were examined with DLCT and MRI. DLCT data was decomposed into hydroxyapatite and water- and fat-equivalent volume fraction maps. Two radiologists assessed DLCT-based volume fraction maps for the presence of perifocal BME, using a Likert scale (1 = no edema; 2 = likely no edema; 3 = likely edema; 4 = edema). Accuracy, sensitivity, and specificity for the detection of BME on DLCT were analyzed using MR findings as standard of reference. For the detection of BME in patients with OO, DLCT showed a sensitivity of 0.92, a specificity of 0.94, and an accuracy of 0.92 for both radiologists. Interreader agreement for the assessment of BME with DLCT was substantial (weighted κ = 0.78; 95% CI, 0.59, 0.94). DLCT with material-specific volume fraction maps allowed accurate detection of BME in patients with OO. This may spare patients additional examinations and facilitate the diagnosis of OO.

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