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See detailImage Quality evaluation for 124I in the microPET Focus 120 scanner using the NEMA NU4-2008 phantom
Bahri, Mohamed Ali ULg; Warnock, Geoffrey ULg; Taleb, Dounia ULg et al

Conference (2011, January 17)

Physical properties of iodine-124 such as its high positron energy, corresponding large positron range in tissue and the fraction of the single γ-photons emitted may have detrimental effects on the PET ... [more ▼]

Physical properties of iodine-124 such as its high positron energy, corresponding large positron range in tissue and the fraction of the single γ-photons emitted may have detrimental effects on the PET image quality. The purpose of this work was to evaluate the image quality for iodine-124 in the small animal microPET Focus 120 scanner using the NEMA NU4-2008 image quality phantom. Although the 2 ns timing window gives higher recovery coefficients and slightly lower spill-over ratios and combined with the 350-590 keV energy window gives the lowest spill-over ratio, the combination of the 350-650 keV and 6 ns windows seems to be the best compromise to obtain images with high contrast and low noise content. [less ▲]

Detailed reference viewed: 63 (5 ULg)
See detailImage Quality, Accuracy of Attenuation and Scatter Corrections of the microPET Focus 120 Using the NEMA NU4-2008 Phantom
Bahri, Mohamed Ali ULg; Plenevaux, Alain ULg; Seret, Alain ULg

Poster (2008, October)

This work aimed at evaluating the image quality and the accuracy of attenuation and scatter corrections methodologies provided with the microPET Focus 120 scanner. The protocol used here is described in ... [more ▼]

This work aimed at evaluating the image quality and the accuracy of attenuation and scatter corrections methodologies provided with the microPET Focus 120 scanner. The protocol used here is described in the forthcoming NEMA NU4-2008 document. This study included 1 h transmission experiments, with two sources (68Ge and 57Co, both one half-live old), in coincidence mode (Ge) with and without windowing, and singles mode (Ge and Co). Transmission data with Co were also collected for shorter acquisition times (515/1030/2060 s). Transmission with scatter correction, and emission with attenuation with or without scatter correction, slices were reconstructed using 2D-FBP (ramp filter). The uniformity, the recovery coefficients (RC) and the accuracy of corrections were evaluated as described in the NEMA document. We also determined the attenuation coefficient (AC) for water using the methodology applied to measure the mean pixel value for the emission slices of the uniform part of the phantom. The Co single mode measurements provided a mean AC for water closer to the theoretical value than the Ge measurements either in single or in coincidence mode even for the shortest acquisition time. Moreover, the lowest coefficients of variation per pixel of the uniform slices were measured for attenuation corrected data based on Co measurements. Also, spill-over ratio for non-emitting air and water compartments reflected a higher capability of this attenuation correction method for scatter correction. The RC measured on emission image corrected only for attenuation did not show any significant difference linked to the transmission measured methods. However, higher RC values were noted for Ge coincidence with windowing when emission data were corrected for both attenuation and scatter. Hence, Co singles transmission seems to be the most suitable method for attenuation correction on the microPET Focus 120 scanner. [less ▲]

Detailed reference viewed: 72 (19 ULg)
See detailImage Reconstruction from Strip Integrals in Computer-aided X-ray Tomography
Verly, Jacques ULg; Bracewell, Ronald N.

Conference (1979, August)

Detailed reference viewed: 12 (3 ULg)
See detailImage reconstruction in X-ray tomography
Toye, Dominique ULg; Fransolet, Emmanuelle; Léonard, Angélique ULg et al

Scientific conference (2004, August)

Detailed reference viewed: 13 (5 ULg)
See detailIMAGE SATELLITAIRE - Planche IX.1 du Deuxième Atlas de Belgique
Cornélis, Bernard; Binard, Marc ULg

Cartographic material (1996)

Detailed reference viewed: 37 (0 ULg)
See detailImage satellitaire de la Belgique – Commentaire de la planche IX-1 (en 4 langues)
Donnay, Jean-Paul ULg; Cornélis, Bernard

in Comité Belge de Géographie (Ed.) Atlas National de Belgique (1996)

Detailed reference viewed: 4 (0 ULg)
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See detailL'image scientifique : de la visualisation à la mathématisation et retour
Dondero, Maria Giulia ULg

in Nouveaux Actes Sémiotiques (2009)

Cet article soumet à investigation les rôles des images dans la production en laboratoire et dans la littérature scientifique de l’astrophysique et de la physique théorique. D’un côté l’image en ... [more ▼]

Cet article soumet à investigation les rôles des images dans la production en laboratoire et dans la littérature scientifique de l’astrophysique et de la physique théorique. D’un côté l’image en astrophysique fonctionne en tant qu’instrument d’enregistrement des données permettant de caractériser un phénomène (régime autographique) : dans ce cas l’image transforme les traces d’un phénomène en un objet (nébuleuse, supernova, etc.), produit d’une négociation, qui sera ensuite accepté, stabilisé et institutionnalisé à l’intérieur de la discipline. De l’autre côté, l’image peut aussi devenir un instrument d’investigation, voire un terrain de travail visant la production d’autres iconographies et ainsi d’autres objets. Ce dernier fonctionnement de l’image relève du régime allographique (voir Nelson Goodman, Les langages de l’art. Pour une théorie des symboles, 1968) : dans ce cas l’image se présente comme un texte d’instructions pour la production d’autres images : elle devient un texte générateur et permet une mathématisation des données. En prenant ensuite en considération les recherches en physique théorique sur les trous noirs, notre article étudie la relation entre équations et visualisation. On étudie plus précisément la première iconographie des trous noirs proposée par l’astrophysicien Jean-Pierre Luminet en 1979. Les travaux de Luminet qu’on analyse dans notre article montrent l’effort de construction d’une iconographie d’un objet théorique ni visible ni photographiable tel les trous noirs, et la nécessité de visualiser les résultats des équations pour faire avancer les hypothèses et la connaissance de ces phénomènes. Enfin, l’image en physique théorique, produite par des équations, montre le pouvoir que la visualisation a de mettre en scène un objet pluriel, voire un certain type de trous noirs, et de devenir ainsi une image modèle mais toujours ultérieurement manipulable (diagramme). [less ▲]

Detailed reference viewed: 52 (8 ULg)
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See detailL’image scientifique : Pratiques de production, visualisation et interpretation
Dondero, Maria Giulia ULg

in Nouveaux Actes Sémiotiques (2008)

Detailed reference viewed: 36 (2 ULg)
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See detailImage scientifique et énonciation du temps
Dondero, Maria Giulia ULg

in Visible (2009), 5

Detailed reference viewed: 32 (2 ULg)
See detailImage(s) de soi, image(s) de l’autre
Lanneau, Catherine ULg

Conference (2010, October 16)

Detailed reference viewed: 7 (2 ULg)
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See detailImage-based Finite Element Mesh Generation for Microstructures
D'Otreppe, Vinciane ULg; Mengoni, Marlène ULg; Boman, Romain ULg et al

Conference (2011, November 14)

Detailed reference viewed: 72 (33 ULg)
See detailIMAGE-FUV multispectral observation of theta auroras.
Hubert, Benoît ULg; Gérard, Jean-Claude ULg; Mende, S. B. et al

Conference (2002, May 01)

The theta aurora is an auroral structure presenting a sun-aligned transpolar arc. Five different dynamic evolution of the transpolar arcs are known, some of them being symmetrical to each other, leaving ... [more ▼]

The theta aurora is an auroral structure presenting a sun-aligned transpolar arc. Five different dynamic evolution of the transpolar arcs are known, some of them being symmetrical to each other, leaving three basically different types of transpolar auroral features. The theta aurora was previously studied with in-situ particles detectors onboard polar orbiting satellites and by ultraviolet imagers. Previous imaging works focused on the electron aurora. We use the FUV imagers onboard the IMAGE spacecraft to study separately the proton and electron contributions to the transpolar arcs at the global scale. The imagers of the IMAGE-FUV experiment remotely sense the electron aurora with the WIC and SI13 imagers observing respectively the N[SUB]2[/SUB]-LBH and OI-135.6 nm emission, while the SI12 spectrographic imager measures the Doppler-shifted Lyman-ë± emission which is solely due to the auroral proton precipitation. The three different types of transpolar aurora will be analyzed using the IMAGE-FUV imagers. In particular, the relative contribution of proton and electron to the excitation of the theta aurora will be presented. [less ▲]

Detailed reference viewed: 13 (0 ULg)
See detailImage-guided neurosurgery ...
Verly, Jacques ULg

Scientific conference (2004)

Detailed reference viewed: 3 (0 ULg)
See detailImage-guided surgery: the engineer’s view- point
Verly, Jacques ULg; Vigneron, Lara M.; Kavec, Martin et al

Scientific conference (2005)

Detailed reference viewed: 4 (0 ULg)
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See detailLas imágenes de España, de Franco y de la monarquía en las guías turísticas del Patrimonio Nacional (1959-1987)
Vanden Berghe, Kristine ULg; Maddens, Bart

in Ayer. Revista de historia Contemporánea (2008), 70(2), 241-262

In this article, a discourse analysis is presented of the tourist guides published by the ‘Patrimonio Nacional’ or National Heritage, charged with the administration and preservation of the Spanish royal ... [more ▼]

In this article, a discourse analysis is presented of the tourist guides published by the ‘Patrimonio Nacional’ or National Heritage, charged with the administration and preservation of the Spanish royal sites. The analysis focuses on the guides published during the Franco era and the transition. These guides portray Spain as a nation with a deep-seated monarchist tradition, which was however usurped by the ‘decadent’ Borbon dynasty. At the same time the figure of Franco is subtly associated with the monarchy and somehow inserted in the royal imagery, both on the iconographical and textual levels. Most radically, two sites which bear no relationship with the monarchy – the Palacio de la Isla in Burgos and the Valley of the Fallen – are discursively incorporated in the royal heritage. By creating a link between Franco and the monarchist tradition, the regime attempted to enhance its legitimacy. Franco’s semi-regal status assured that his rise to power was viewed not so much as a result of a chance occurrence of circumstances but rather as a preordained succession. In the guides published during the transition, the association between Franco and the monarchy is still present, but the ideology is hidden behind a more historic discourse, a result of which Franco appears as a half forgotten historic figure. [less ▲]

Detailed reference viewed: 78 (2 ULg)
See detailImágenes en Colón, imágenes de Colón.
Vanden Berghe, Kristine ULg

Book published by Label (2007)

Detailed reference viewed: 21 (3 ULg)
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See detailImagerie cérébrale de la réflexion sur soi
Salmon, Eric ULg; D'Argembeau, Arnaud ULg; Bastin, Christine ULg et al

in Revue Médicale de Liège (2008), 63

Precise brain regions are activated when a subject gives a judgment on himself. Those are the medial parietal cortex, essentially related to episodic memory processing, and the ventromedial prefrontal ... [more ▼]

Precise brain regions are activated when a subject gives a judgment on himself. Those are the medial parietal cortex, essentially related to episodic memory processing, and the ventromedial prefrontal cortex, recruited for evaluating the personal valence of an information. These regions are not activated in Alzheimer's disease. The decrease of awareness for own deficits in a patient with Alzheimer's disease would depend on a reduction of episodic memory capacities and a worsening of judgment for self significance. [less ▲]

Detailed reference viewed: 74 (16 ULg)
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See detailImagerie d'une infiltration artificielle d'eau salée à la côte belge par tomographie de résistivité électrique contrainte par des données géostatistiques
Hermans, Thomas ULg; Nguyen, Frédéric ULg

Scientific conference (2011, January 14)

Electrical resistivity tomography is a geophysical method widely used for salt water intrusion studies, thanks to its ability to detect salinity contrasts. In this context, boreholes are often available ... [more ▼]

Electrical resistivity tomography is a geophysical method widely used for salt water intrusion studies, thanks to its ability to detect salinity contrasts. In this context, boreholes are often available to improve the interpretation of inverted models. The main objective of this study is to incorporate a priori information contained in borehole data to constrain the geophysical inversion with a geostatistical constraint based on the variogram. A synthetic benchmark showed that the choice of the prior model played a great role in the inversion process, especially in low sensitivity zones. The use of simulations conditioned with borehole data costs a lot of time because it is necessary to run several inversions to obtain a mean solution. The methodology was applied to artificial salt water infiltrations in the Westhoek nature reserve. In this case, a homogeneous prior model deduced from borehole data seemed judicious. Inversion results enabled to determine the extension of the salt water plume laterally, in depth, but also in terms of total dissolved solid content (TDS). These observations are in agreement with the hydrogeological situation of the site. A comparison with borehole data showed that the results are much more satisfying than a traditional smoothness constraint used as a regularization tool. [less ▲]

Detailed reference viewed: 47 (11 ULg)
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See detailImagerie de la microcirculation cutanée défaillante.
QUATRESOOZ, Pascale ULg; REGINSTER, Marie-Annick ULg; FRANCHIMONT, Claudine ULg et al

in Dermatologie Actualité (2010), 123

Le réseau microvasculaire de la peau joue des rôles physiologiques majeurs en oxygénant les tissus et en permettant des échanges thermiques finement régulés. Son parcours résistif et capacitif module les ... [more ▼]

Le réseau microvasculaire de la peau joue des rôles physiologiques majeurs en oxygénant les tissus et en permettant des échanges thermiques finement régulés. Son parcours résistif et capacitif module les résistances périphériques au débit sanguin. La microvascularisation est sous l’influence de divers facteurs, mais globalement, elle semble presque immuable dans la peau saine. En revanche, certaines circonstances pathologiques engendrent des hyperplasies ou des hypoplasies vasculaires. Parfois aussi, le réseau semble garder son extension normale, mais sa structure intime est remaniée. Cette revue est un florilège d’aspects microscopiques associés à des perturbations majeures de la fonctionnalité vasculaire cutanée. [less ▲]

Detailed reference viewed: 18 (0 ULg)