Investigation of radiation absorption and X-ray fluorescence properties of medical imaging scintillators by Monte Carlo methods

Nikolopoulos, Dimitrios; Kandarakis, I.; Cavouras, D.; Valais, I.; Linardatos, Dionysios; Michail, C.; Stoppa, David; Gaitanis, Anastasios; Nomicos, C.; Louizï, A.

doi:10.1016/j.nima.2006.05.170

Cited by 5 publications

(10 citation statements)

References 27 publications

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“…Furthermore, the fact that the photon detection sensitivity increases with the thickness of the 64 LSO crystals block (Figure 7, Table 3) points in another way that blocks of thicker crystals detect and count more photons. This is in agreement with the higher detection efficiency of the thicker crystals [5,17,18].…”

Section: Resultssupporting

confidence: 89%

See 1 more Smart Citation

A GATE Simulation Study of the Siemens Biograph DUO PET/CT System

Nikolopoulos¹,

Kottou²,

Chatzisavvas³

et al. 2013

OJRad

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This is a GATE-simulation study of the Siemens Biograph DUO PET/CT system. It reports effects of changes in the thickness of the employed Lutetium Oxyorthosilicate (LSO) detectors. The PET/CT, a human body phantom and a cylindrical F-18 FDG source were simulated. Validation measurements were conducted. The results indicate that LSO thickness increase degrades spatial resolution, improves relative energy resolution from 9.0% to 11.3% and increases signal-to-noise-ratio from 0.81 to 1.17. Thicker LSO crystals present greater axial sensitivity so as the detection efficiency of PET would be significantly enhanced.

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Section: Resultssupporting

confidence: 89%

“…The peak of the 3.0 cm thick crystals is sharper than the one of the 2.0 cm thickness. This can be attributed to the higher detection efficiency of the thicker LSO detectors at 0.511 MeV [5,17,18]. Counts corresponding to energies higher than 0.511 MeV are obtained.…”

Section: Resultsmentioning

confidence: 97%

A GATE Simulation Study of the Siemens Biograph DUO PET/CT System

Nikolopoulos¹,

Kottou²,

Chatzisavvas³

et al. 2013

OJRad

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“…Additionally, when X-rays interact with a phosphor (by most pronounced photo-electric effect), X-ray fluorescence photons are produced which may be reabsorbed by the detector areas adjacent to the primary x-ray interaction site. This may cause a loss of spatial resolution and an increase in image noise [5] [6]. Moreover, the fluorescence optical photon may also scatter within the scintillator layer which causes blurring, also known as veiling glare [7] [8].…”

Section: Introductionmentioning

confidence: 99%

Separable scatter model of the detector and object contributions using continuously thickness-adapted kernels in CBCT

Bhatia

Tisseur

Valton³

et al. 2016

XST

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Due to the increased cone beam coverage and the introduction of flat panel detector, the size of X-ray illumination fields has grown dramatically in Cone Beam Computed Tomography (CBCT), causing an increase in scatter radiation. Existing reconstruction algorithms do not model the scatter radiation, so scatter artifacts appear in the reconstruction images. The contribution of scattering of photons inside the detector itself becomes prominent and challenging in case of X-ray source of high energy (over a few 100 keV) which is used in typical industrial Non Destructive Testing (NDT). In this paper, comprehensive evaluation of contribution of detector scatter is performed using continuously thickness-adapted kernels. A separation of scatter due to object and the detector is presented using a four-Gaussian model. The results obtained prove that the scatter correction only due to the object is not sufficient to obtain reconstruction image free from artifacts as the detector also scatters considerably. The obtained results are also validated experimentally using a collimator to remove the contribution of object scatter.

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“…Other scintillators, such as Gd 2 SiO 5 (GSO), LuAlO 3 (LuAP), YAlO 3 (YAP) and Y 3 Al 5 O 12 (YAG) have been employed as well [1,3,4]. Noticeable is the recent tendency in introducing new detector types and designs [2,3,[6][7][8][9][10]. Modern PET imaging technology involves, nowadays, algorithms for statistical effects, scatter and random coincidences, fast detector electronics and accurate reconstruction algorithms [1,3,11,12].…”

Section: Introductionmentioning

confidence: 99%

“…This intensifies the interest for investigations on already employed PET systems [5,7,11,[14][15][16][17][18][19][20][21][22] and in seeking applicability of new detector concepts. In designing and evaluating new PET systems, it is of significance to determine accurately various physical phenomena associated with radiation detection [3,4,6,7]. For example, incorrectly detected scatter and characteristic X-ray fluorescence radiation, bremsstrahlung, Auger and Koster-Kronig electrons, could result in significant degradation of spatial resolution and image contrast [18,19].…”

Section: Introductionmentioning

confidence: 99%

GATE Simulation of the Biograph 2 PET/CT Scanner

C¹

2014

J Nucl Med Radiat Ther

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GATE is advanced open source software dedicated to numerical simulations in medical imaging and radiotherapy. It currently supports simulations of Emission Tomography (Positron Emission Tomography -PET and Single Photon Emission Computed Tomography -SPECT), Computed Tomography (CT) and Radiotherapy experiments. This work focused on the commercial Biograph 6 PET/CT scanner. The study targeted to (a) port previously developed and validated GATE codes to the currently available stable version GATE v.6.1, (b) evaluate model's validity detecting sources of bias (c) investigate differentiations imposed if different sources were employed, namely F-18 (Fluorine-18), O-15 (Oxygen-15) and . The geometry of the system components was described in GATE, including detector ring, crystal blocks, PMTs etc. Energy and spatial resolution were taken into account. The GATE results were compared to experimental data obtained according to the NEMA NU-2-2001 protocol, Analysis was limited to scatter fraction, count looses and randoms. Good agreement was achieved between experimental and GATE results. Significant sources of bias were the (a) dead time value, (b) dead-time mode (paralysable-nonparalysable), (c) modelled activity (d) modelled source, (e) additional dead time values adopted in GATE modules.

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Investigation of radiation absorption and X-ray fluorescence properties of medical imaging scintillators by Monte Carlo methods

Cited by 5 publications

References 27 publications

A GATE Simulation Study of the Siemens Biograph DUO PET/CT System

A GATE Simulation Study of the Siemens Biograph DUO PET/CT System

Separable scatter model of the detector and object contributions using continuously thickness-adapted kernels in CBCT

GATE Simulation of the Biograph 2 PET/CT Scanner

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