Strategies of statistical windows in PET image reconstruction to improve the user s real time experience

[EN] Nowadays, with the increase of the computational power of modern computers together with the state-of-the-art reconstruction algorithms, it is possible to obtain Positron Emission Tomography (PET) images in practically real time. These facts open the door to new applications such as radio-pharmaceuticals tracking inside the body or the use of PET for image-guided procedures, such as biopsy interventions, among others. This work is a proof of concept that aims to improve the user experience with real time PET images. Fixed, incremental, overlapping, sliding and hybrid windows are the different statistical combinations of data blocks used to generate intermediate images in order to follow the path of the activity in the Field Of View (FOV). To evaluate these different combinations, a point source is placed in a dedicated breast PET device and moved along the FOV. These acquisitions are reconstructed according to the different statistical windows, resulting in a smoother transition of positions for the image reconstructions that use the sliding and hybrid window.This study has been realized in the context of the European Union's Seventh Framework Programme for research. L. Moliner was financed with VALi+d program grant.Moliner Martínez, L.; Correcher Salvador, C.; Giménez-Alventosa, V.; Ilisie, V.; Álvarez-Gómez, JM.; Sánchez Góez, S.; Rodríguez-Álvarez, M. (2017). Strategies of statistical windows in PET image reconstruction to improve the user s real time experience. Journal of Physics: Conference Series (Online). 931:1-4. https://doi.org/10.1088/1742-6596/931/1/012025S1493

The Challenge of Detection and Diagnosis of Fugacious Hardware Faults in VLSI Designs

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-38789-0_7Current integration scales are increasing the number and types of faults that embedded systems must face. Traditional approaches focus on dealing with those transient and permanent faults that impact the state or output of systems, whereas little research has targeted those faults being logically, electrically or temporally masked -which we have named fugacious. A fast detection and precise diagnosis of faults occurrence, even if the provided service is unaffected, could be of invaluable help to determine, for instance, that systems are currently under the influence of environmental disturbances like radiation, suffering from wear-out, or being affected by an intermittent fault. Upon detection, systems may react to adapt the deployed fault tolerance mechanisms to the diagnosed problem. This paper explores these ideas evaluating challenges and requirements involved, and provides an outline of potential techniques to be applied.This work has been funded by Spanish Ministry of Economy ARENES project (TIN2012-38308-C02-01)Espinosa García, J.; Andrés Martínez, DD.; Ruiz, JC.; Gil, P. (2013). The Challenge of Detection and Diagnosis of Fugacious Hardware Faults in VLSI Designs. En Dependable Computing. Springer. 76-87. https://doi.org/10.1007/978-3-642-38789-0_7S7687Narayanan, V., Xie, Y.: Reliability concerns in embedded systems design. IEEE Computer 1(39), 118–120 (2006)Hannius, O., Karlsson, J.: Impact of soft errors in a jet engine controller. In: Ortmeier, F., Daniel, P. (eds.) SAFECOMP 2012. LNCS, vol. 7612, pp. 223–234. Springer, Heidelberg (2012)Borkar, S.: Designing reliable systems from unreliable components: the challenges of transistor variability and degradation. IEEE Micro 25(6), 10–16 (2005)JEDEC: Measurement and reporting of alpha particle and terrestrial cosmic ray-induced soft errors in semiconductor devices. JEDEC Standard JESD89A. JEDEC (2006)Gracia-Moran, J., Gil-Tomas, D., Saiz-Adalid, L.J., Baraza, J.C., Gil-Vicente, P.J.: Experimental validation of a fault tolerant microcomputer system against intermittent faults. In: DSN, pp. 413–418 (2010)Constantinescu, C.: Intermittent faults and effects on reliability of integrated circuits. In: Proceedings of the 2008 Annual Reliability and Maintainability Symposium, pp. 370–374. IEEE Computer Society, Washington, DC (2008)Avizienis, A., Laprie, J.C., Randell, B., Landwehr, C.: Basic concepts and taxonomy of dependable and secure computing. IEEE Trans. Dependable Secur. Comput. 1, 11–33 (2004)Johnson, C., Holloway, C.: The dangers of failure masking in fault-tolerant software: Aspects of a recent in-flight upset event. In: 2007 2nd Institution of Engineering and Technology International Conference on System Safety, pp. 60–65 (October 2007)Bolchini, C., Salice, F., Sciuto, D.: Fault analysis for networks with concurrent error detection. IEEE Des. Test 15(4), 66–74 (1998)Goessel, M., Ocheretny, V., Sogomonyan, E., Marienfeld, D.: New Methods of Concurrent Checking (Frontiers in Electronic Testing), 1st edn. Springer Publishing Company, Incorporated (2008)Iyer, R.K., Rossetti, D.J.: A statistical load dependency model for cpu errors at slac. In: Twenty-Fifth International Symposium on Fault-Tolerant Computing, ‘Highlights from Twenty-Five Years’, p. 373 (June 1995)Dodd, P.E., Shaneyfelt, M.R., Felix, J.A., Schwank, J.R.: Production and propagation of single-event transients in high-speed digital logic ics. IEEE Transactions on Nuclear Science 51, 3278–3284 (2004)Nightingale, E.B., Douceur, J.R., Orgovan, V.: Cycles, cells and platters: an empirical analysisof hardware failures on a million consumer pcs. In: Proceedings of the Sixth Conference on Computer Systems, EuroSys 2011, pp. 343–356. ACM, New York (2011)Kimseng, K., Hoit, M., Tiwari, N., Pecht, M.: Physics-of-failure assessment of a cruise control module. Microelectronics Reliability 39(10), 1423–1444 (1999)Savir, J.: Detection of single intermittent faults in sequential circuits. IEEE Trans. Comput. 29(7), 673–678 (1980)Correcher, A., Garcia, E., Morant, F., Quiles, E., Rodriguez, L.: Intermittent failure dynamics characterization. IEEE Transactions on Reliability 61(3), 649–658 (2012)Sorensen, B., Kelly, G., Sajecki, A., Sorensen, P.: An analyzer for detecting intermittent faults in electronic devices. In: AUTOTESTCON 1994. 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Uncertainty on radiation doses estimated by biological and retrospective physical methods

Biological and physical retrospective dosimetry are recognised as key techniques to provide individual estimates of dose following unplanned exposures to ionising radiation. Whilst there has been a relatively large amount of recent development in the biological and physical procedures, development of statistical analysis techniques has failed to keep pace. The aim of this paper is to review the current state of the art in uncertainty analysis techniques across the ‘EURADOS Working Group 10— Retrospective dosimetry’ members, to give concrete examples of implementation of the techniques recommended in the international standards, and to further promote the use of Monte Carlo techniques to support characterisation of uncertainties. It is concluded that sufficient techniques are available and in use by most laboratories for acute, whole body exposures to highly penetrating radiation, but further work will be required to ensure that statistical analysis is always wholly sufficient for the more complex exposure scenarios

Review of retrospective dosimetry techniques for external ionising radiation exposures

The current focus on networking and mutual assistance in the management of radiation accidents or incidents has demonstrated the importance of a joined-up approach in physical and biological dosimetry. To this end, the European Radiation Dosimetry Working Group 10 on 'Retrospective Dosimetry' has been set up by individuals from a wide range of disciplines across Europe. Here, established and emerging dosimetry methods are reviewed, which can be used immediately and retrospectively following external ionising radiation exposure. Endpoints and assays include dicentrics, translocations, premature chromosome condensation, micronuclei, somatic mutations, gene expression, electron paramagnetic resonance, thermoluminescence, optically stimulated luminescence, neutron activation, haematology, protein biomarkers and analytical dose reconstruction. Individual characteristics of these techniques, their limitations and potential for further development are reviewed, and their usefulness in specific exposure scenarios is discussed. Whilst no single technique fulfils the criteria of an ideal dosemeter, an integrated approach using multiple techniques tailored to the exposure scenario can cover most requirements. © The Author 2010. Published by Oxford University Press. All rights reserved

Herbivory on the pedunculate oak along an urbanization gradient in Europe : Effects of impervious surface, local tree cover, and insect feeding guild

Urbanization is an important driver of the diversity and abundance of tree-associated insect herbivores, but its consequences for insect herbivory are poorly understood. A likely source of variability among studies is the insufficient consideration of intraurban variability in forest cover. With the help of citizen scientists, we investigated the independent and interactive effects of local canopy cover and percentage of impervious surface on insect herbivory in the pedunculate oak (Quercus robur L.) throughout most of its geographic range in Europe. We found that the damage caused by chewing insect herbivores as well as the incidence of leaf-mining and gall-inducing herbivores consistently decreased with increasing impervious surface around focal oaks. Herbivory by chewing herbivores increased with increasing forest cover, regardless of impervious surface. In contrast, an increase in local canopy cover buffered the negative effect of impervious surface on leaf miners and strengthened its effect on gall inducers. These results show that – just like in non-urban areas – plant-herbivore interactions in cities are structured by a complex set of interacting factors. This highlights that local habitat characteristics within cities have the potential to attenuate or modify the effect of impervious surfaces on biotic interactions.Agence Nationale de la Recherche, Grant/Award Number: ANR-10--LABX-45; Fondation BNP Paribas.info:eu-repo/semantics/publishedVersio

Diseño y primeros resultados de una cámara PET para animales pequeños basada en cristales LYSO continuos y fotomulplicadores sensibles a la posición

[ES] En este artículo presentamos el diseño de un nuevo escáner PET para animales pequeños basado en una tecnología completamente innovadora. Los resultados preliminares son muy prometedores, permitiendo obtener imágenes funcionales de alta resolución con una instrumentación compacta y de bajo coste. Los prototipos desarrollados se encuentran actualmente en pruebas en diversos centros de investigación médica, obteniéndose imá- genes de alta calidad en los campos de oncología, neurología y cardiología. Este diseño puede ser fácilmente extendido a cámaras PET dedicadas a la exploración del cerebro o de la mama. La innovación más notable de la presente tecnología consiste en el uso de un único cristal continuo por módulo, a diferencia de otras cámaras PET comerciales donde se utilizan cientos de cristales pixelados. El uso de un único cristal continuo permite abaratar el coste de fabricación, al tiempo que mejora las características de funcionamiento: resolución intrínseca en posición de 1,2 mm, resolución en energía media del 14%, resolución en la profundidad de interacción de 3 mm, sensibilidad > 4% y campo de visión transaxial de 80 mm de diámetro. En el presente artículo se describen en detalle el diseño de esta nueva cámara PET, los principios de funcionamiento, el método utilizado para su calibración y se anticipan algunas imágenes "in vivo" del miocardio y el cerebro de un ratón, permitiendo apreciar de forma preliminar la resolución y calidad alcanzadas.[EN] In this paper we present the design of a new small animal PET scanner based on a completely innovative technology. The achieved results are very promising, showing the possibility to obtain high resolution functional images with a compact and low cost scanner. Several prototypes have been developed and are currently being used at different research medical institutions. High resolution images are being obtained in application fields like oncology, neurology and cardiology. This technology can be easily applied in PET cameras for brain or breast exploration. The most significant innovation of the design is the fact of using a single crystal per module instead of hundreds of pixellated crystals as in other commercial PETs. It has the advantage of decreasing the manufacturing costs and simultaneously improves its performance: 1.2 mm position intrinsic resolution, mean energy resolution as good as 14%, 3 mm depth of interaction resolution, sensitivity above 4%, and 80 mm diameter of transaxial field of view. In this paper we describe in detail the design of this new PET camera, its principle, the calibration methodology and also some preliminary "in vivo" images of a mouse myocardium and brain, showing the achieved image resolution and qualityBenlloch Baviera, JM.; González Martínez, AJ.; Carrilero, V.; Catret, JV.; Correcher, C.; Lerche, CW.; Morera, C.... (2007). Diseño y primeros resultados de una cámara PET para animales pequeños basada en cristales LYSO continuos y fotomulplicadores sensibles a la posición. Revista de física médica. 8(2):315-321. http://hdl.handle.net/10251/79285S3153218

Herbivory on the pedunculate oak along an urbanization gradient in Europe: Effects of impervious surface, local tree cover, and insect feeding guild

Urbanization is an important driver of the diversity and abundance of tree-associated insect herbivores, but its consequences for insect herbivory are poorly understood. A likely source of variability among studies is the insufficient consideration of intra-urban variability in forest cover. With the help of citizen scientists, we investigated the independent and interactive effects of local canopy cover and percentage of impervious surface on insect herbivory in the pedunculate oak (Quercus robur L.) throughout most of its geographic range in Europe. We found that the damage caused by chewing insect herbivores as well as the incidence of leaf-mining and gall-inducing herbivores consistently decreased with increasing impervious surface around focal oaks. Herbivory by chewing herbivores increased with increasing forest cover, regardless of impervious surface. In contrast, an increase in local canopy cover buffered the negative effect of impervious surface on leaf miners and strengthened its effect on gall inducers. These results show that-just like in non-urban areas-plant-herbivore interactions in cities are structured by a complex set of interacting factors. This highlights that local habitat characteristics within cities have the potential to attenuate or modify the effect of impervious surfaces on biotic interactions

Search for top-down and bottom-up drivers of latitudinal trends in insect herbivory in oak trees in Europe

AimThe strength of species interactions is traditionally expected to increase toward the Equator. However, recent studies have reported opposite or inconsistent latitudinal trends in the bottom‐up (plant quality) and top‐down (natural enemies) forces driving herbivory. In addition, these forces have rarely been studied together thus limiting previous attempts to understand the effect of large‐scale climatic gradients on herbivory.LocationEurope.Time period2018–2019.Major taxa studiedQuercus robur.MethodsWe simultaneously tested for latitudinal variation in plant–herbivore–natural enemy interactions. We further investigated the underlying climatic factors associated with variation in herbivory, leaf chemistry and attack rates in Quercus robur across its complete latitudinal range in Europe. We quantified insect leaf damage and the incidence of specialist herbivores as well as leaf chemistry and bird attack rates on dummy caterpillars on 261 oak trees.ResultsClimatic factors rather than latitude per se were the best predictors of the large‐scale (geographical) variation in the incidence of gall‐inducers and leaf‐miners as well as in leaf nutritional content. However, leaf damage, plant chemical defences (leaf phenolics) and bird attack rates were not influenced by climatic factors or latitude. The incidence of leaf‐miners increased with increasing concentrations of hydrolysable tannins, whereas the incidence of gall‐inducers increased with increasing leaf soluble sugar concentration and decreased with increasing leaf C : N ratios and lignins. However, leaf traits and bird attack rates did not vary with leaf damage.Main conclusionsThese findings help to refine our understanding of the bottom‐up and top‐down mechanisms driving geographical variation in plant–herbivore interactions, and indicate the need for further examination of the drivers of herbivory on trees.</p