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Aim Metallic components from circular external fixators, including the Ilizarov frame, cause artefacts on X-rays and obstruct clear visualisation of bone detail. We evaluated the ability of tomosynthesis to reduce interference on radiographs caused by metal artefacts and developed an optimal image acquisition method for such cases. Materials and methods An Ilizarov frame phantom was constructed using rods placed on the bone for the purpose to evaluate the benefits of tomosynthesis. Distances between the rod and bone and the angle between the rod and X-ray tube orbit were set at three different levels. Filtered backprojection images were reconstructed using two different features of the reconstruction function: THICKNESS−− (CONTRAST4) and THICKNESS++ (METAL4); the first is suitable for improving contrast and the second is suitable for metal artefacts. The peak signal-to-noise ratio (PSNR) was used during image evaluation to determine the influence of the metallic rod on bone structure visibility. Results The PSNR increased as the angle between the metal rod and the X-ray tube orbit and the distance between the metallic rod and bone increased. The PSNR was larger when using THICKNESS−− (CONTRAST4) than when using THICKNESS++ (METAL4). Conclusion The optimal reconstruction function and image acquisition determined using the metallic rod in this study suggest that quality equal to that without the metallic rod can be obtained. Clinical significance We describe an optimised method for image acquisition without unnecessary acquisition repetition and unreasonable posture changes when the bone cannot be adequately visualised. How to cite this article Abe Y, Shimada M, Takeda Y, et al. Evaluation of Patient Positioning during Digital Tomosynthesis and Reconstruction Algorithms for Ilizarov Frames: A Phantom Study. Strategies Trauma Limb Reconstr 2020;15(1):1–6.

Ziel: Das Ziel dieser Arbeit ist, zu erforschen, wie die Rekonstruktionsparameter, im Speziellen das iterative Rekonstruktionsverfahren SAFIRE, die durch das Metall des Left Ventricular Assist Device verursachten Metallartefakte bei einem Herz-CTA beeinflussen können. Methode & Material: Um die Forschungsfrage beantworten zu können, wird ein Experiment auf Basis des Forschungsstandes durchgeführt. Dafür werden Computertomographie-Aufnahmen von einem linken Herzventrikel-Phantom an der Fachhochschule Campus Wien durchgeführt. Der verwendete Computertomograph von der Firma Siemens Healthineers trägt den Namen Somatom go.all. Während den Aufnahmen befindet sich ein Kupfermetallstück eines Left Ventricular Assist Device im Apex des Phantoms, um die dabei entstehenden Metallartefakte zu simulieren. Die CTA-Aufnahme wird mit fünf verschiedenen SAFIRE-Werten rekonstruiert. Anschließend können mittels der Software Mimics von Materialise die Datensätze segmentiert, 3D-Masken erstellt und diese ausgewertet werden. Für die Auswertung werden die Volumina und Oberflächen der unterschiedlichen SAFIRE-Rekonstruktionen verglichen. Eine weitere Erkenntnisgewinnung bietet der Oberflächenvergleich, welcher mittels der Software 3-matic erstellt wird. Ergebnisse: Bei der Analyse der Oberflächen und dem Volumen der 3D-Masken der fünf Rekonstruktionen waren die Ergebnisse direkt proportional zu dem verwendeten Iterationsschritten. Mit zunehmender Steigung der Iterationen reduzierte sich die Oberfläche und das Volumen. Dieses Ergebnis bestätigte die Oberflächendifferenzmessung, welche alle fünf Iterationsschritte mit der Standarditeration verglichen hat. Hierbei hatten jene Masken mit vier und fünf Iterationen eine kleinere Artefakt-Maske als jene mit drei Iterationen. Diskussion: Die empirische Arbeit zeigt, dass das iterative Verfahren einen signifikanten Unterschied in der Artefaktausprägung verursacht und dadurch die Bildqualität verbessert. Da eine adäquate Bildqualität eine bessere Diagnose und Therapieplanung zur Folge hat, soll das Experiment dazu anregen in diesem Gebiet weiterzuforschen und das Iterative verfahren zu verbessern. Aim: To explore how the reconstruction parameters, such as the iterative reconstruction procedure SAFIRE, can influence the artifacts caused by the Left Ventricular Assist Device metal in a cardiac CTA. Methods & Materials: In order to answer the research question, an experiment was performed based on the state-of-the-art research. For this purpose, computed tomography scans of a left ventricular phantom were performed at the University of Applied Sciences Campus Vienna. The computer tomograph used from the Siemens Healthineers company is called Somatom go.all. For the images a copper metal piece of a Left Ventricular Assist Device was implanted in the Apex of the Phantom to simulate the resulting metal artifacts. The CT image was reconstructed using five different SAFIRE values. The Mimics software was then used to segment the data sets, to create 3D masks, and to evaluate them. For the evaluation, the volumes and surfaces of the different SAFIRE reconstructions were compared. The surface comparison, which was created using the 3-matic software, provides further insights. Results: When analyzing the surface areas and volumes of the 3D masks of the five reconstructions, the results were directly proportional to the iteration steps used. As the slope of the iterations increased, the surface area and volume decreased. This result was confirmed in the surface difference measurement, which compared all five iteration steps to the standard iteration. Here, those masks with four and five iterations had a smaller artifact mask than those with three iterations. Discussion: The empirical work shows that iterative procedures cause a significant difference in artifact expression and thus improve image quality. Since adequate image quality results in better diagnosis and therapy planning, the experiment should encourage further research in this area and improve the iterative procedure.

Les nombreux dépôts métalliques (objets isolés, dépôts multiples et sites en milieu humide) de l’âge du Bronze et du premier âge du Fer, recensés pour la Normandie, ont été replacés au sein d’un SIG. L’étude met en valeur plusieurs facteurs ayant pu influer sur leur implantation et se construit autour de cartes de répartition des sites, de densité de mobilier, ainsi que de cartes de répartition des sites au sein du relief. La Normandie n’est pas touchée de la même manière par les enfouissements au cours du temps : du chalcolithique au début du Bronze final atlantique, les dépôts sont présents en grand nombre principalement dans l’est de la zone d’étude, la vallée de la Seine ressortant plus particulièrement. Puis au cours du Bronze final, les aires denses en dépôt changent et se déplace vers l’ouest pour finir, à l’âge du Fer, avec les nombreux dépôts de haches à douilles de type armoricain. Les cartes de densité de mobilier donnent une vision parfois un peu différente : le meilleur exemple est la zone de la plaine de Caen qui présente au Bronze moyen un nombre de dépôt assez modeste, comparé à la Seine, mais qui représente une quantité d’objets déposés presque équivalente. Les dépôts en milieu humide sont également connus du début de l’âge du Bronze au premier âge du Fer. La plupart des dépôts fluviaux sont des découvertes de la Seine mais un certain nombre de dépôts en eaux stagnantes sont aussi connus : dans des mares, marais et tourbières. La vallée de la Seine a bénéficié d’une attention particulière et permis d’effectuer une étude plus locale. Dans ce but, les sites funéraires et d’habitat connus pour cette zone ont été ajouté à l’étude afin de comparer leur répartition et leur implantation dans le relief avec celles des dépôts. Si les dépôts terrestres sont présents tout le long du fleuve, entre Vernon et Honfleur, les sites en milieu humide sont surtout connus dans les méandres entre Poses et Le Trait. C’est principalement dans cet espace que, tout au long de l’âge du Bronze, les plus grandes concentrations d’objets déposés sont observées. À l’échelle de la Normandie, les dépôts sont présents dans l’ensemble des types de relief : vallées, plateaux, pentes et crètes, mais une attraction des pentes et un rejet des plateaux semblent visible. Dans la vallée de la Seine, on constate que les vallées et plateaux sont réservés à l’habitat et aux sites funéraires, et les dépôts sont présents dans les autres reliefs. Bronze Age and Iron Age metal hoards (single artefact, dry-land and wet deposits) observed for Normandy, have been inputted in a GIS. This study shows some factors which could influence establishment of hoards and is based on different maps: distribution of sites, density of artefacts and localization of si te in landforms.Over time, Normandy hasn’t been impacted by burying in the same way: from Chalcolithic to Late Bronze Age, hoards are mainly concentrated in East Normandy, in Seine valley particularly. Then, during the Late Bronze Age, concentrations of hoards moved to West Normandy until the First Iron Age, with hoards of Armorican-type socketed axes. Sometimes, density of artefacts give another vision than distribution of site: the best instance is Caen lowland where, during the Middle Bronze Age, the number of hoards is smaller than the Seine valley, whereas the number of artefacts is quite similar. Wet deposits are also observed for all Bronze Age and First Iron Age. Most of fluvial deposits have been discovered in Seine but some artefacts were buried in stagnant waters: ponds, swamps and bogs.Seine valley has been chosen for a local study. Domestic and funeral sites, discovered in this area, have been added to the corpus in order to compare their distribution and establishment in the relief with hoards. Even if dry-land deposits are settled all along the river, between Vernon and Honfleur, wet deposits are mainly found between Poses and Le Trait. During all Bronze Age, the biggest concentration of artefacts is observed mostly in this area.In Normandy, hoards are settled in all kind of landforms: valley, plateau, slopes and peaks but slopes seem preferred and plateau rejected. In the Seine valley, valley and plateau are reserved for domestic and funeral sites, and hoards are present in other landforms. Los numerosos depósitos metálicos (objetos aislados, depósitos múltiples y acuáticos) de la Edad del Bronce y la Primera Edad del Hierro inventariados en Normandía se han colocado en un SIG. El estudio destaca varios factores que pueden haber influido en su ubicación y se basa en los mapas de distribución de yacimientos, la concentración de objetos y los mapas de distribución de los yacimientos en función de la topografía. Normandía no se ve afectada de la misma manera por los depósitos a lo largo del tiempo: del Calcolítico al comienzo del Bronce Final Atlántico, están presentes en grandes cantidades principalmente en la parte oriental del área de estudio, destacando el valle del Sena. A continuación, durante el Bronce Final, las áreas de concentración de depósitos cambiaron y se desplazaron hacia el oeste, terminando en la Edad del Hierro con los numerosos depósitos de hachas de cubo de tipo armoricano. Los mapas de distribución de los objetos dan una visión en ocasiones ligeramente distinta: el mejor ejemplo es la llanura en torno a Caen que presenta durante el Bronce Medio un número de depósitos bastante modesto, en comparación con el Sena, pero que representa una cantidad de objetos depositados casi equivalente. Los depósitos acuáticos también se conocen desde el Bronce Antiguo hasta la Edad de Hierro. La mayoría de los depósitos fluviales proceden del Sena, pero también se conocen varios depósitos en aguas estancadas: en charcas, pantanos y turberas. El valle del Sena ha recibido una atención especial y ha permitido realizar un estudio más localizado. Con este propósito, los yacimientos funerarios y los poblados conocidos en este área se han añadido al estudio para comparar su distribución y su ubicación topográfica con las de los depósitos. Si los depósitos terrestres aparecen a lo largo de todo el cauce del río, entre Vernon y Honfleur, los acuáticos lo hacen sobre todo en los meandros entre Poses y Le Trait. Es principalmente en este espacio donde, a lo largo de la Edad de Bronce, se observan las mayores concentraciones de objetos depositados. Al nivel de toda Normandía, los depósitos aparecen en todo tipo de contextos topográficos: valles, mesetas, pendientes y crestas, pero se aprecia una atracción por las pendientes en detrimento de las zonas altas. En el valle del Sena, encontramos que los valles y las mesetas se reservan para el poblamiento y el mundo funerario, y los depósitos aparecen en el resto de ubicaciones.

Passados mais de dez anos após a primeira campanha de escavações realizada em Monte Molião, e apesar de o sítio ter sido já alvo de inúmeras publicações, o conjunto de artefactos metálicos da Idade do Ferro aguardava ainda a sua divulgação. Neste trabalho, apresenta-se e estuda-se a totalidade dos elementos metálicos recolhidos nos contextos sidéricos, que se analisam de acordo com as várias categorias em que se podem incluir, concretamente: arquitectura e mobiliário, uso pessoal, e utilitários. Cada um dos artefactos foi analisado individualmente, tendo em atenção o seu contexto de recolha, bem como os dados cronológicos que os seus paralelos permitiram obter. A discussão sobre a funcionalidade de muitos deles permitiu uma aproximação à realidade social e económica da comunidade que habitou o sítio e das suas relações inter-regionais, lidas em função do mobiliário utilizado, do vestuário usado e das actividades económicas praticadas., Ten years after the first excavation in Monte Molião the set of metal artefacts from the Iron Age was still awaiting its publication, although the site has been subject of numerous publications. We present all the metallic elements collected in Iron Age contexts, included in several of the established fields: architecture, furniture, personal domains and instruments. Each of the artefacts was analysed taking into account the context where they were discovered, as well as the chronological data of similar findings. The discussion about their functionality allowed an approximation to the social and economic reality of the community that inhabited the site and their interregional connections regarding furniture, clothing and economic activities., Más de diez años después de la primera campaña de excavación en Monte Molião, y a pesar de que el yacimiento ya había sido objeto de numerosas publicaciones, el conjunto de objetos metálicos de la Edad de Hierro aún estaba esperando su divulgación. En este trabajo se presentan y estudian todos los elementos metálicos recogidos en los contextos de dicho periodo, los cuales se analizan en función de las distintas categorías en las que se pueden incluir, en concreto: arquitectura y mobiliario, uso personal y utilitario. Cada uno de los artefactos fue analizado individualmente, teniendo en cuenta su contexto de aparición, así como los datos cronológicos que su paralelismo permitía obtener. La discusión sobre la funcionalidad de muchos de ellos permitió una aproximación a la realidad social y económica de la comunidad que habitaba el sitio y sus relaciones interregionales, leídas en función del mobiliario utilizado, la ropa usada y las actividades económicas realizadas.

The aim was to compare the effects of metal artifacts from a pacemaker on pulmonary nodule detection among computed tomography (CT) images reconstructed using filtered back projection (FBP), single-energy metal artifact reduction (SEMAR), and forward-projected model-based iterative reconstruction solution (FIRST). Nine simulated nodules were placed inside a chest phantom with a pacemaker. CT images reconstructed using FBP, SEMAR, and FIRST were acquired at low and standard dose, and were evaluated by 2 independent radiologists. FIRST demonstrated the most significantly improved metal artifact and nodule detection on low dose CT (P

External fixation is a common tool in the treatment of complex fractures, correction of limb deformity, and salvage arthrodesis. These devices typically incorporate radio-opaque metal rods/struts connected at varying distances and orientations between rings. Whilst the predominant imaging modality is plain film radiology, computed tomography (CT) may be performed in order for the surgeon to make a more confident clinical decision (e.g. timing of frame removal, assessment of degree of arthrodesis). We used a fractured sheep leg to systematically assess CT imaging performance with a Discovery CT750 HD CT scanner (GE Healthcare) to show how rod coupling in both traditional Ilizarov and hexapod frames distorts images. We also investigated the role of dual-energy CT (DECT) and metal artefact reduction software (MARS) on the visualisation of the fractured leg. Whilst mechanical reasons predominantly dictate the rod/strut configurations when building a circular frame, rod coupling in CT can be minimised. Firstly, ideally, all or all but one rod can be removed during imaging resulting in no rod coupling. If this is not possible, strategies for configuring the rods to minimise the effect of the rod coupling on the region of interest are demonstrated, e.g., in the case of a four-rod construct, switching the two anterior rods to a more central single one will achieve this goal without particularly jeopardising mechanical strength for a short period. It is also shown that the addition of DECT and MARS results in a reduction of artefacts, but also affects tissue and bone differentiation.

Cet article présente les résultats d’une recherche menée sur deux années de master à l’Université de Nantes. Engagée en 2013 sous la direction de Yves Henigfeld et de Vincent Legros, elle porte sur le mobilier métallique médiéval des habitats ruraux des Pays de la Loire occupés entre le ve et le xve siècle (Raffin, 2013-2014 ; Raffin, 2014-2015). Les corpus concernés sont issus des différentes opérations préventives, programmées ou de sauvetage, réalisées dans la région entre 1985 et 2011. Ce travail synthétique présente des données pour la plupart inédites et propose un état des lieux régional de la recherche sur le mobilier métallique médiéval en contexte d’habitat rural. L’étude d’un peu moins de 500 éléments métalliques a permis de mettre en évidence des artefacts issus de la vie quotidienne témoignant des différentes activités pratiquées au sein des habitats et des équipements dont ils bénéficiaient. This paper aims to present the results of research carried out for my Master’s degree under the direction of Yves Henigfeld and Vincent Legros at Nantes University. The research focuses on medieval metal artefacts from rural settlements dating from the 5th to the 15th century in the Pays de Loire, the corpus being from preventive, rescue or programmed excavations that were carried out between 1985 and 2011. This work presents mostly unpublished data and proposes a regional overview of research on metal objects from settlement contexts. The study of up to 500 household objects has underlined the diverse activities that went on in settlements and the different tools and equipment that were used. Dieser Beitrag präsentiert die Ergebnisse von Untersuchungen der Metallfunde aus mittelalterlichen ländlichen Siedlungen des 5. bis 15. Jahrhunderts in der Region Pays-de-Loire (Raffin, 2013-2014 ; Raffin, 2014-2015). Die Arbeiten wurden im Rahmen eines zweijährigen Masterstudiums an der Universität von Nantes unter der Leitung von Yves Henigfeld und Vincent Legros vorgenommen. Das untersuchte Fundmaterial stammt aus verschiedenen Rettungs- und Forschungsgrabungen, die in der Region in den Jahren zwischen 1985 und 2011 durchgeführt wurden. Diese zusammenfassende Übersicht präsentiert überwiegend bisher unveröffentlichtes Fundmaterial und stellt den aktuellen regionalen Forschungsstand zu den mittelalterlichen Metallobjekten aus ländlichen Siedlungen dar. Die Untersuchung von etwas mehr als 500 Metallobjekten hat es gestattet, die Werkzeuge und Geräte des täglichen Lebens zu analysieren, die die verschiedenen Tätigkeiten in den Siedlungen widerspiegeln.

X-ray Computed Tomography (XCT) has become an important tool for industrial measurement and quality control through its ability to measure internal structures and volumetric defects. Segmentation of constituent materials in the volume acquired through XCT is one of the most critical factors that influence its robustness and repeatability. Highly attenuating materials such as steel can introduce artefacts in CT images that adversely affect the segmentation process, and results in large errors during quantification. This paper presents a Markov Random Field (MRF) segmentation method as a suitable approach for industrial samples with metal artefacts. The advantages of employing the MRF segmentation method are shown in comparison with Otsu thresholding on CT data from two industrial objects.

Příspěvek seznamuje s rozborem železných a kovových artefaktů získaných během detektorového průzkumu v roce 2011 a souboru předaného amatérským hledačem kovů ze dvou zaniklých středověkých vsí Prochod a Žďár ve Velechvínském polesí. Předměty byly zhodnoceny s ohledem na jejich typologické a funkční zařazení do příslušných skupin. Ve srovnání se soubory železných a kovových artefaktů ze systematicky zkoumaných zaniklých středověkých vsí v Čechách a na Moravě a dalších lokalit z jižních Čech je řešena otázka chronologie a způsob využití předmětů v soudobé živé kultuře. Sledována je i otázka distribuce a nálezový kontext předmětů, vzhledem ke zjištěným reliéfním tvarům dokumentovaným prostřednictvím geodeticko-topografického průzkumu. The paper deals with analysis of iron and metal artefacts recovered under the supervision of the author during a metal detector survey in 2011 and assemblages handed over by an amateur ‘treasure hunter’ originating from two deserted medieval villages, Prochod and Žďár, in the Velechvín forest district. The objects were evaluated with regard to their typological and functional classification into relevant groups. Compared to assemblages of iron and metal artefacts from systematically investigated DMVs in Bohemia and Moravia and other sites in South Bohemia, the issue of chronology and the way of using objects in contemporary living culture are addressed. The question of distribution and the context of the objects are also dealt with, in context of relief formations documented through geodetic-topographic survey.

BackgroundThe rate of retear after rotator cuff surgery is 17%. Magnetic resonance imaging (MRI) scans are used for confirmative diagnosis of retear. However, because of the presence of titanium suture anchors, metal artefacts on the MRI are common. The present study evaluated the diagnostic value of MRI after rotator cuff tendon surgery with respect to assessing the integrity as well as the degeneration and atrophy of the rotator cuff tendons when titanium anchors are in place.MethodsTwenty patients who underwent revision surgery of the rotator cuff as a result of a clinically suspected retear between 2013 and 2015 were included. The MRI scans of these patients were retrospectively analyzed by four specialized shoulder surgeons and compared with intra-operative findings (gold standard). Sensitivity and interobserver agreement among the surgeons in assessing retears as well as the Goutallier and Warner classification were examined.ResultsIn 36% (range 15% to 50%) of the pre-operative MRI scans, the observers could not review the rotator cuff tendons. When the rotator cuff tendons were assessable, a diagnostic accuracy with a mean sensitivity of 0.84 (0.70 to 1.0) across the surgeons was found, with poor interobserver agreement (kappa = 0.12).ConclusionsMetal artefacts prevented accurate diagnosis from MRI scans of rotator cuff retear in 36% of the patients studied.

Purpose To quantify the impact of prosthesis material and design on the reduction of metal artefacts in total hip arthroplasties using virtual monochromatic dual-layer detector Spectral CT imaging. Methods The water-filled total hip arthroplasty phantom was scanned on a novel 128-slice Philips IQon dual-layer detector Spectral CT scanner at 120-kVp and 140-kVp at a standard computed tomography dose index of 20.0 mGy. Several unilateral and bilateral hip prostheses consisting of different metal alloys were inserted and combined which were surrounded by 18 hydroxyapatite calcium carbonate pellets representing bone. Images were reconstructed with iterative reconstruction and analysed at monochromatic energies ranging from 40 to 200 keV. CT numbers in Hounsfield Units (HU), noise measured as the standard deviation in HU, signal-to-noise-ratios (SNRs) and contrast-to-noise-ratios (CNRs) were analysed within fixed regions-of-interests placed in and around the pellets. Results In 70 and 74 keV virtual monochromatic images the CT numbers of the pellets were similar to 120-kVp and 140-kVp polychromatic results, therefore serving as reference. A separation into three categories of metal artefacts was made (no, mild/moderate and severe) where pellets were categorized based on HU deviations. At high keV values overall image contrast was reduced. For mild/moderate artefacts, the highest average CNRs were attained with virtual monochromatic 130 keV images, acquired at 140-kVp. Severe metal artefacts were not reduced. In 130 keV images, only mild/moderate metal artefacts were significantly reduced compared to 70 and 74 keV images. Deviations in CT numbers, noise, SNRs and CNRs due to metal artefacts were decreased with respectively 64%, 57%, 62% and 63% (p

Background: To determine if metal artefact reduction (MAR) combined with a priori knowledge of prosthesis material composition can be applied to obtain CT-based attenuation maps with sufficient accuracy for quantitative assessment of 18F-fluorodeoxyglucose uptake in lesions near metallic prostheses. Methods: A custom hip prosthesis phantom with a lesion-sized cavity filled with 0.2 ml 18F-FDG solution having an activity of 3.367 MBq adjacent to a prosthesis bore was imaged twice with a chrome-cobalt steel hip prosthesis and a plastic replica, respectively. Scanning was performed on a clinical hybrid PET/CT system equipped with an additional external 137Cs transmission source. PET emission images were reconstructed from both phantom configurations with CT-based attenuation correction (CTAC) and with CT-based attenuation correction using MAR (MARCTAC). To compare results with the attenuation- correction method extant prior to the advent of PET/CT, we also carried out attenuation correction with 137Cs transmission-based attenuation correction (TXAC). CTAC and MARCTAC images were scaled to attenuation coefficients at 511 keV using a trilinear function that mapped the highest CT values to the prosthesis alloy attenuation coefficient. Accuracy and spatial distribution of the lesion activity was compared between the three reconstruction schemes. Results: Compared to the reference activity of 3.37 MBq, the estimated activity quantified from the PET image corrected by TXAC was 3.41 MBq. The activity estimated from PET images corrected by MARCTAC was similar in accuracy at 3.32 MBq. CTAC corrected PET images resulted in nearly 40 % overestimation of lesion activity at 4.70 MBq. Comparison of PET images obtained with the plastic and metal prostheses in place showed that CTAC resulted in a marked distortion of the 18F-FDG distribution within the lesion, whereas application of MARCTAC and TXAC resulted in lesion distributions similar to those observed with the plastic replica. Conclusions: MAR combined with a trilinear CT number mapping for PET attenuation correction resulted in estimates of lesion activity comparable in accuracy to that obtained with 137Cs transmission-based attenuation correction, and far superior to estimates made without attenuation correction or with a standard CT attenuation map. The ability to use CT images for attenuation correction is a potentially important development because it obviates the need for a 137Cs transmission source, which entails extra scan time, logistical complexity and expense. © 2014 The Japanese Society of Nuclear Medicine.

Purpose: Quantification of the effect of O-MAR on decreasing metal artefacts caused by large head metal on metal total hip arthroplasty (MoM THA) in a dedicated phantom setup of the hip. Background: Pathological reactions of the hip capsule on Computed tomography (CT) can be difficult to diagnose due to different metal artefacts. The O-MAR algorithm deploys an iterative loop where the metal sinogram is identified, extracted, and subsequently serves as a mask to correct the measured sinogram. Main goal of this study is to quantify the ability of the O-MAR technique to correct deviation in medullary bone attenuation caused by streak artefacts from the large-head MoM THA embedded in a phantom. Secondary goal is to evaluate the influence of O-MAR on CNR. Methods: The phantom was designed as a Perspex box (PMMA) containing water and a supplementary MOM THA surrounded by Perspex columns comprising calibrated calcium pellets. Each column contains 200 mg of hydroxyapatite/calcium carbonate to simulate healthy bone tissue. Scans were obtained with and without a MoM THA at different dose levels. Different reconstructions were made with filter A, iDose(4) level 5 and with and without O-MAR. The scans without the prosthesis were used as the baseline. Information about the attenuation in Hounsfield units, image noise in standard deviation within the ROI's were extracted and the CNR was calculated. Results: Pellet L0 and R0 (proximal of the MoM THA) were defined as reference, lacking any disturbance by metal artefacts; L5, L6 and L8 were respectively visually categorized as 'light' 'medium' and 'heavy disturbance'. Significant improvements in attenuation deviation caused by metal artefact were 43, 68 and 32 %, for respectively pellet L5, L6 and L8 (p

Purpose Metallic prosthetic replacements, such as hip or knee implants, are known to cause strong streaking artefacts in CT images. These artefacts likely induce over-or underestimation of the activity concentration near the metallic implants when applying CT-based attenuation correction of positron emission tomography (PET) images. Since this degrades the diagnostic quality of the images, metal artefact reduction (MAR) prior to attenuation correction is required.Methods The proposed MAR method, referred to as virtual sinogram-based technique, replaces the projection bins of the sinogram that are influenced by metallic implants by a 2-D Clough-Tocher cubic interpolation scheme performed in an irregular grid, called Delaunay triangulated grid. To assess the performance of the proposed method, a physical phantom and 30 clinical PET/CT studies including hip prostheses were used. The results were compared to the method implemented on the Siemens Biograph mCT PET/CT scanner.Results Both phantom and clinical studies revealed that the proposed method performs equally well as the Siemens MAR method in the regions corresponding to bright streaking artefacts and the artefact-free regions. However, in regions corresponding to dark streaking artefacts, the Siemens method does not seem to appropriately correct the tracer uptake while the proposed method consistently increased the uptake in the underestimated regions, thus bringing it to the expected level. This observation is corroborated by the experimental phantom study which demonstrates that the proposed method approaches the true activity concentration more closely.Conclusion The proposed MAR method allows more accurate CT-based attenuation correction of PET images and prevents misinterpretation of tracer uptake, which might be biased owing to the propagation of bright and dark streaking artefacts from CT images to the PET data following the attenuation correction procedure.

Diese Arbeit ist ein vollständiges Studium der Metallfunde aus den zwei Handwerkervierteln von Bliesbruck (Moselle, Frankreich). Diese Funde stammen aus vierzigjahrelangen Ausgrabungen. Das Korpus besteht aus 450 Kg Metall (Eisen, Kupferlegierungen, weisse Metalle, Gold) wovon 4 200 Objekte und 22 000 Nägel. Eine Objekt- und Funktionsidentifizierung und eine typologische Nägelzahl haben es ermöglicht, die Objektverbindungen wieder zusammenzusetzen und die Daten nach verschiedenen Kriterien einander gegenüberzustellen : Metall, Lage (Viertel und Grundstück), Chronologie und Befundnummertyp. Diese Datenüberfülle und -verschiedenheit ermöglichen das Korpus nach vielartigen geographischen Maβstäben und Themen zu studieren. Es kann also zuerst vorgestellt werden, dass jedes Grundstück seine eigene Geschichte hat und auch dabei seine eigene Metallfundeverbindung. Wenn diese spezielle Verbindung berücksichtigt wird und die Objektanwesenheit oder -abwesenheit klargestellt wird, ist es möglich die Räume oder Gebäude zu karakterisieren (Handwerk, Strasse, usw.). Diese Phase wurde durch die Benutzung eines geographischen Informationssystem (GIS) erleichtert. Die thematische Studie des Betätingungsfelds (Ökonomie, Schmuck, Transports, usw.) kann dann einerseits die gemeinsamen Punkte der zwei Vierteln und andererseits die Besonderheiten des Ortes Bliesbruck bestimmen. Durch diese Methode, die die archäologische Stätten vergleicht, möchte diese Arbeit ein Glied in der Kette der Wissenschaft über die gallo-römischen Metallfunde aus Ostfrankreich sein., This work is an exhaustive study of the metal artefacts of the two craft-quarters of the roman vicus Bliesbruck (Moselle). These artefacts come from the diggings which take place in Bliesbruck since forty years. The corpus contains 450 kg of metals (iron, copper, white metals and gold). The artefacts are separated into 4 200 objects and 22 000 nails. Thanks to the object's identification, the knowledge of their function and the count of nails, it is possible on the one hand to reconstitute the object's assembling and on the other hand to confront the data with various points of view : kind of metal, found-place (quarter and plot of land), chronology, kind of stratigraphic unit. With the abundance and diversity of data the corpus can be studied with different geographical scales and themes. It appears first that each plot of land has his own history and a specific assembling of metal artefacts. If this specification is taken into consideration and the presence or absence of artefacts too, it's possible to characterize each place (craft, street, etc.). This kind of reflection is easier thanks to the utilisation of a Geographical Information-system (GIS). Than, the thematic approach depending on domains (economy, personal effects, transportation, etc.) can show on the one hand the general tendencies of the both quarters and on the other hand the specificities of Bliesbruck as opposed to other sites. To confront archaeological sites, this work would like to be a piece of the knowledge of metal artefacts coming from East France., Le présent travail consiste en une étude exhaustive du mobilier métallique des deux quartiers artisanaux du vicus gallo-romain de Bliesbruck (Moselle). Ce mobilier a été mis au jour lors des différentes campagnes de fouilles qui se sont déroulées sur le site durant les quarante dernières années. Le corpus obtenu englobe 450 kg de métaux (fer, alliage cuivreux, métaux blancs, or) qui se répartissent entre 4 200 objets et 22 000 clous. Grâce à un travail d'identification de chaque objet et de détermination de sa fonction, associé à un comptage typologique des clous, il a été à la fois possible de reconstituer les assemblages de mobilier et de confronter les données en fonction de différents critères comme la nature du métal, la provenance (quartier et parcelle), la chronologie ou encore la nature des unités stratigraphiques. L'abondance des données et leur diversité permet d'appréhender ce corpus à diverses échelles géographiques et de façon thématique. Il apparaît dans un premier temps que chacune des vingt-six parcelles étudiées possède sa propre histoire de même qu'un faciès de mobilier métallique spécifique. En le prenant en compte et en raisonnant en terme de présence/absence, la caractérisation des espaces est alors rendue possible (artisanats, zone de circulation, etc). Cette démarche est facilitée par la visualisation des données à l'aide d'un Système d'Information Géographique (SIG). Dans un second temps, l'approche thématique du corpus en fonction de domaines usuels (économie, effets personnels, transports, etc.) permet d'une part de dégager les tendances générales communes aux deux quartiers et d'autre part de mettre en exergue d'éventuelles spécificités de la zone étudiée face à d'autres sites. Dans cette démarche de mise en perspective de sites, la présente étude se propose donc d'être un maillon dans la connaissance du mobilier métallique gallo-romain de l'Est de la France.

U članku su predstavljeni rezultati početne faze konzervatorsko-restauratorskih radova na avarodobnim metalnim, arheološkim nalazima s lokaliteta Nuštar, dvorac Khuen-Belassy koji se datiraju u drugu polovinu 8. stoljeća. Brojem prevladavaju predmeti od bakrene slitine, željeznih je manje, a olovni, srebrni i zlatni su rijetki. Tijekom restauratorskih radova ustanovljeno je i dokumentirano bojenje, pozlaćivanje i namjerno izazivanje patine. Predmeti su vrlo kvalitetne zanatske izrade i visoke estetske vrijednosti. Radovi se provode od 2011. godine u suradnji Hrvatskoga restauratorskog zavoda i Gradskog muzeja Vinkovci, čijem fundusa pripadaju navedeni predmeti, a financira ih Ministarstvo kulture RH. Premda će tek nakon njihova završetka biti mo-guće cjelovito sagledati i prikazati rezultate istraživanja već i ovi prvi radovi doprinose boljem poznavanju tehnologije izrade avarskih metalnih predmeta., The paper presents the results of the initial phase of con-servation work on the Avarian-age metal archaeological finds from the site of Nuštar, Khuen-Belassy Mansion, dated to the second half of the 8th century. The finds are mostly artefacts made from copper-alloy and to a lesser extent iron, whereas those made from lead, silver and gold are rare. In the course of conservation it was established and documented that they had been painted, gilded and intentionally patinated. The artefacts demonstrate a supreme level of workmanship and a high aesthetic value. Conservation has been ongoing since 2011, in the collaboration of the Croatian Conservation Institute and the Vinkovci Town Museum, and financed by the Ministry of Culture of the Republic of Croatia. Although it is only after the conservation that a comprehensive overview and presentation will be possible, these initial works already contribute to a better understanding of the Avarian technology of metal artefacts production.

In the literature, the ability to transform metal compounds into metal oxalates has been reported for different species of fungi. This could be an innovative conservation method for archaeological and artistic metal artefacts. In fact, with a high degree of insolubility and chemical stability even in acid atmospheres (pH 3), metal oxalates provide the surface with good protection. Within the framework of the EU-ARTECH project, different fungal strains have been used to transform existing corrosion patinas on outdoor bronze monuments into copper oxalates, while preserving the physical appearance of these artefacts. Given the promising results obtained with this first attempt, the same approach is now applied within the BAHAMAS (Marie Curie Intra European Fellowship action) project, but extended to other metal substrates, for example iron and silver, which are frequently found in cultural heritage artworks and also encounter several problems of active corrosion. The research is investigating the formation mechanisms and adhesion properties of the newly formed metal oxalates by means of complementary analytical techniques (X-ray diffraction (XRD), FTIR microscopy, Raman microscopy, scanning electron microscopy (SEM-EDS), electrochemical impedance spectroscopy (EIS), colorimetry). For each metal substrate, the most appropriate fungal strain is going to be identified and applied to corroded sheets and the novel fungal treatment compared with those used so far. Treated metal sheets will be monitored during 1-year exposure to different cycles of artificial ageing, to evaluate the corrosion resistance of the fungal patinas obtained. The objective of this contribution is to present the first results achieved so far on naturally corroded bronze sheets during the EU-ARTECH project and the analytical procedure used for the testing of the proposed treatment performances during the BAHAMAS project.

Este trabajo examina el papel de la metalurgia y las producciones metálicas en la ideología de las sociedades ibéricas de la fase inicial de la Edad del Bronce (c. 2200-1500 cal ANE), utilizando como caso de estudio el Suroeste de la península Ibérica. Con este fin se realiza una revisión del registro empírico disponible para las prácticas funerarias prestando especial atención a la presencia de producciones metálicas y a la asociación de las mismas a individuos de especial estatus social. Como conclusión se propone una lectura de los datos disponibles en clave sociológica, discutiendo cuestiones relativas a la relevancia de las producciones metálicas en las dinámicas de desigualdad y jerarquización social. This paper examines the role of metallurgy and metal productions in the ideology of Early Bronze Age societies (c. 2200-1500 cal ANE) in the Iberian South-West. To this end, a review of the empirical record available for the study of funerary practices is made. Particular attention is paid to the presence of metal objects in funerary contexts, as well as their association to people of higher social status. As a conclusion, the relevant evidence is examined in sociological terms. A number of issues concerning the relevance of metal productions in the dynamics of social inequality and social hierarchisation are discussed.

Non-destructive characterization of bronze artefacts from archaeological finds of the 'Terramare'dwellings near Modena, Italy, was carried out by time-of-flight neutron scattering at the ISIS spallation neutron source of the Rutherford Appleton Laboratory, UK. This provides information on ancient metal technology and its development through the Bronze Age in that region. Six pieces from three different classes as to use and manufacture, from the Middle to Late Bronze Age, were investigated on the ROTAX and GEM beam lines at ISIS, providing a comparison between results from the two instruments. A comparison is also made with three axes of the same area of provenance (Emilia, Terramare culture) from the Early, Middle and Late Bronze Age respectively, analysed previously. Data collected provide stable refinements of the phase fractions and lattice parameters by the Rietveld method, allowing determination of Sn contents from the unit cell expansion due to the incorporation of Sn into the Cu-type alpha-phase. Notably, two of the objects exhibit a range of Sn contents in the bulk as is evident from broad diffraction peaks (4-8 and 10-14 wt% Sn), while the other four artefacts have more defined Sn contents of 8, 9, 10 and 14.5 wt% respectively. The higher Sn weight fractions are associated with the presence of pure unalloyed Cu, interestingly coexisting in one case with two bronze phases (alpha and the eutectoid delta). One sample shows the presence of 2-3 wt% Pb. Varying amounts of oxidation products such as cuprite were identified. Texture information extracted from the diffraction data provided some indications of different working treatments of the analysed objects.

In the framework of the PROMET project (European Commission contract No. 509126) aimed to develop new analytical techniques and materials for monitoring and protecting metal artefacts and monuments from the Mediterranean region, the corrosion products grown on silver Roman coins during archaeological burial is studied by means of scanning electron microscopy combined with energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD) and optical microscopy (OM) techniques.

The Sainte-Propice hilltop settlement at Velaux (B.-du-Rh.). The Late Antiquity occupation. In the lower Arc valley, the Sainte-Propice plateau revealed a pre-Roman settlement, where later structures were built during the Late Antiquity period, and mainly in the northwestern extremity of the site. A limited excavation in this last zone enabled to unearth the stone foundations of a single dwelling. The article is mainly concerned with the analysis of the different types of pottery brought to light in the strata related to this habitation : clear Terra Sigillata D ceramic, sigillata -derived Early Christian ware, common pottery made of dark clay (local or imported). The explored house seem to have lasted a relatively short period, between the middle of the 5th to, at the latest, the middle of the 6th century A. D., Dans la basse vallée de l'Arc, le plateau de Sainte-Propice montre les traces d'un habitat préromain et d'une réimplantation au cours de l'Antiquité tardive, principalement vers son extrémité nord-ouest. Dans ce dernier secteur, une fouille limitée en superficie a permis d'exhumer les soubassements en pierre sèche d'une unité d'habitation. L'essentiel de l'article porte sur l'analyse des différentes catégories de céramiques contenues dans la couche d'occupation contemporaine de l'habitation reconnue : Sigillée claire D, Dérivées-des-Sigillées Paléochrétiennes, communes à pâte sombre (régionales ou importées). L'occupation du bâtiment exploré paraît devoir se situer dans une période relativement brève, entre le milieu du Verne et au plus tard le milieu du VIème s. de n. è., Boixadera Michel, Bonifay Michel, Pelletier Jean-Pierre, Rigoir Jacqueline, Rigoir Yves, Rivet Lucien. L'habitat de hauteur de Sainte-Propice (Velaux, B.-du-Rh.). L'occupation de l'Antiquité tardive. In: Documents d'Archéologie Méridionale, vol. 10, 1987. pp. 91-113.