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  1. 75 FR 11169 - Reedsport OPT Wave Park Project; Reedsport OPT Wave Park; LLC Notice of Scoping Meetings and...

    Science.gov (United States)

    2010-03-10

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 12713-002] Reedsport OPT Wave Park Project; Reedsport OPT Wave Park; LLC Notice of Scoping Meetings and Environmental Site...: Reedsport OPT Wave Park, LLC. e. Name of Project: Reedsport OPT Wave Park Project. [[Page 11170

  2. Projection radiography and tomography

    International Nuclear Information System (INIS)

    Tobias, C.A.; Fabrikant, J.I.; Benton, E.V.; Holley, W.R.

    1980-01-01

    Our program on heavy-ion radiography began soon after heavy ions were accelerated to high energies. Heavy ions are capable of very high electron density discrimination combined with good radial image resolution and low dose. Since heavy-ion beams produce many secondries, plastic nuclear detectors have an advantage for recording heavy-ion images. Projection imaging is now a practical technique that can resolve density differences between normal tissue and tumor tissue in some cases in which X rays could not make a distinction. Initial attempts at heavy-ion tomography also indicate potential for high resolution in this field. The physical basis for heavy-ion radiography and tomographic reconstruction studies are discussed in detail

  3. 3D visualization of the initial Yersinia ruckeri infection route in rainbow trout (Oncorhynchus mykiss) by optical projection tomography

    DEFF Research Database (Denmark)

    Otani, Maki; Villumsen, Kasper Rømer; Kragelund Strøm, Helene

    2014-01-01

    , optical projection tomography (OPT), a novel three-dimensional (3D) bio-imaging technique, was applied. OPT not only enables the visualization of Y. ruckeri on mucosal surfaces but also the 3D spatial distribution in whole organs, without sectioning. Rainbow trout were infected by bath challenge exposure...

  4. OPTiM: Optical projection tomography integrated microscope using open-source hardware and software.

    Science.gov (United States)

    Watson, Thomas; Andrews, Natalie; Davis, Samuel; Bugeon, Laurence; Dallman, Margaret D; McGinty, James

    2017-01-01

    We describe the implementation of an OPT plate to perform optical projection tomography (OPT) on a commercial wide-field inverted microscope, using our open-source hardware and software. The OPT plate includes a tilt adjustment for alignment and a stepper motor for sample rotation as required by standard projection tomography. Depending on magnification requirements, three methods of performing OPT are detailed using this adaptor plate: a conventional direct OPT method requiring only the addition of a limiting aperture behind the objective lens; an external optical-relay method allowing conventional OPT to be performed at magnifications >4x; a remote focal scanning and region-of-interest method for improved spatial resolution OPT (up to ~1.6 μm). All three methods use the microscope's existing incoherent light source (i.e. arc-lamp) and all of its inherent functionality is maintained for day-to-day use. OPT acquisitions are performed on in vivo zebrafish embryos to demonstrate the implementations' viability.

  5. Macro optical projection tomography for large scale 3D imaging of plant structures and gene activity.

    Science.gov (United States)

    Lee, Karen J I; Calder, Grant M; Hindle, Christopher R; Newman, Jacob L; Robinson, Simon N; Avondo, Jerome J H Y; Coen, Enrico S

    2017-01-01

    Optical projection tomography (OPT) is a well-established method for visualising gene activity in plants and animals. However, a limitation of conventional OPT is that the specimen upper size limit precludes its application to larger structures. To address this problem we constructed a macro version called Macro OPT (M-OPT). We apply M-OPT to 3D live imaging of gene activity in growing whole plants and to visualise structural morphology in large optically cleared plant and insect specimens up to 60 mm tall and 45 mm deep. We also show how M-OPT can be used to image gene expression domains in 3D within fixed tissue and to visualise gene activity in 3D in clones of growing young whole Arabidopsis plants. A further application of M-OPT is to visualise plant-insect interactions. Thus M-OPT provides an effective 3D imaging platform that allows the study of gene activity, internal plant structures and plant-insect interactions at a macroscopic scale. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  6. An evaluation of meniscal collagenous structure using optical projection tomography

    International Nuclear Information System (INIS)

    Andrews, Stephen HJ; Ronsky, Janet L; Rattner, Jerome B; Shrive, Nigel G; Jamniczky, Heather A

    2013-01-01

    The collagenous structure of menisci is a complex network of circumferentially oriented fascicles and interwoven radially oriented tie-fibres. To date, examination of this micro- architecture has been limited to two-dimensional imaging techniques. The purpose of this study was to evaluate the ability of the three-dimensional imaging technique; optical projection tomography (OPT), to visualize the collagenous structure of the meniscus. If successful, this technique would be the first to visualize the macroscopic orientation of collagen fascicles in 3-D in the meniscus and could further refine load bearing mechanisms in the tissue. OPT is an imaging technique capable of imaging samples on the meso-scale (1-10 mm) at a micro-scale resolution. The technique, similar to computed tomography, takes two-dimensional images of objects from incremental angles around the object and reconstructs them using a back projection algorithm to determine three-dimensional structure. Bovine meniscal samples were imaged from four locations (outer main body, femoral surface, tibial surface and inner main body) to determine the variation in collagen orientation throughout the tissue. Bovine stifles (n = 2) were obtained from a local abattoir and the menisci carefully dissected. Menisci were fixed in methanol and subsequently cut using a custom cutting jig (n = 4 samples per meniscus). Samples were then mounted in agarose, dehydrated in methanol and subsequently cleared using benzyl alcohol benzyl benzoate (BABB) and imaged using OPT. Results indicate circumferential, radial and oblique collagenous orientations at the contact surfaces and in the inner third of the main body of the meniscus. Imaging identified fascicles ranging from 80-420 μm in diameter. Transition zones where fascicles were found to have a woven or braided appearance were also identified. The outer-third of the main body was composed of fascicles oriented predominantly in the circumferential direction. Blood vessels were

  7. Accelerated Optical Projection Tomography Applied to In Vivo Imaging of Zebrafish.

    Directory of Open Access Journals (Sweden)

    Teresa Correia

    Full Text Available Optical projection tomography (OPT provides a non-invasive 3-D imaging modality that can be applied to longitudinal studies of live disease models, including in zebrafish. Current limitations include the requirement of a minimum number of angular projections for reconstruction of reasonable OPT images using filtered back projection (FBP, which is typically several hundred, leading to acquisition times of several minutes. It is highly desirable to decrease the number of required angular projections to decrease both the total acquisition time and the light dose to the sample. This is particularly important to enable longitudinal studies, which involve measurements of the same fish at different time points. In this work, we demonstrate that the use of an iterative algorithm to reconstruct sparsely sampled OPT data sets can provide useful 3-D images with 50 or fewer projections, thereby significantly decreasing the minimum acquisition time and light dose while maintaining image quality. A transgenic zebrafish embryo with fluorescent labelling of the vasculature was imaged to acquire densely sampled (800 projections and under-sampled data sets of transmitted and fluorescence projection images. The under-sampled OPT data sets were reconstructed using an iterative total variation-based image reconstruction algorithm and compared against FBP reconstructions of the densely sampled data sets. To illustrate the potential for quantitative analysis following rapid OPT data acquisition, a Hessian-based method was applied to automatically segment the reconstructed images to select the vasculature network. Results showed that 3-D images of the zebrafish embryo and its vasculature of sufficient visual quality for quantitative analysis can be reconstructed using the iterative algorithm from only 32 projections-achieving up to 28 times improvement in imaging speed and leading to total acquisition times of a few seconds.

  8. Spherical projections and liftings in geometric tomography

    DEFF Research Database (Denmark)

    Goodey, Paul; Kiderlen, Markus; Weil, Wolfgang

    2011-01-01

    We consider a variety of integral transforms arising in Geometric Tomography. It will be shown that these can be put into a common framework using spherical projection and lifting operators. These operators will be applied to support functions and surface area measures of convex bodies and to rad......We consider a variety of integral transforms arising in Geometric Tomography. It will be shown that these can be put into a common framework using spherical projection and lifting operators. These operators will be applied to support functions and surface area measures of convex bodies...... and to radial functions of star bodies. We then investigate averages of lifted projections and show that they correspond to self-adjoint intertwining operators. We obtain formulas for the eigenvalues of these operators and use them to ascertain circumstances under which tomographic measurements determine...... the original bodies. This approach via mean lifted projections leads us to some unexpected relationships between seemingly disparate geometric constructions....

  9. Special section: OptIPlanet - The OptIPuter global collaboratory

    NARCIS (Netherlands)

    Smarr, L.; Brown, M.; de Laat, C.

    The technological developments made by OptIPuter research project as an OptIPlanet Collaboratory of virtual organizations, in various scientific and technology domains, enhancing and contributing to this evolving cyberinfrastructure to solve complex global problems, are summarized. OptIPuter project

  10. Who opts out of a project for health promotion with incentives?: Empirical research on the effect of rewards to motivate persistence.

    Science.gov (United States)

    Okamoto, Shohei; Komamura, Kohei; Tanabe, Kai; Yokoyama, Noriko; Tsukao, Akiko; Chijiki, Shoko; Kuno, Shinya

    2017-01-01

    Objectives Although providing incentives for a better lifestyle has been of increasing concern, there is insufficient evidence about its effect. Therefore, this research aims to discover new insights by verifying the effect of rewards to motivate persistence in a project for health promotion.Methods A total of 7,622 participants of an incentivized project for health promotion (Wellness Point Project) were recruited from 6 municipalities in Japan, namely Tohoku, Chubu, Kanto, Kinki, and Chugoku, of which the 4,291 individuals who had the necessary information for estimation were analyzed. Persistence in the project was judged by whether there was information about daily steps and/or participation in some fitness classes every month for one year at most. In addition, we used the reason participants chose certain rewards in order to categorize the characteristic of rewards, and estimated opt-out hazard ratios from the project using survival time analysis. Furthermore, the estimation in the model included individual features such as age, education, status of physical activity before joining the project, lifestyles such as smoking, drinking, and so on.Results A multivariate analysis reveals that those who had chosen a reward for regional contribution were more likely to opt out than those who had chosen a certain reward because it is close to cash. The opt-out hazard ratio was 1.63 (95% CI: 1.18-2.25) among men and 1.40 (95% CI: 1.08-1.81) among women. In addition, insufficient physical activity, smoking, working for men, and physical condition for women were associated with opt-out.Conclusions This research verified that a reward that participants felt was close to cash, compared to the internal motivation of regional contribution, could enhance the persistence rate of the project. Moreover, it was found that not only giving incentives but also considering participants' conditions is necessary to enhance persistence.

  11. Block matching 3D random noise filtering for absorption optical projection tomography

    International Nuclear Information System (INIS)

    Fumene Feruglio, P; Vinegoni, C; Weissleder, R; Gros, J; Sbarbati, A

    2010-01-01

    Absorption and emission optical projection tomography (OPT), alternatively referred to as optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT), are recently developed three-dimensional imaging techniques with value for developmental biology and ex vivo gene expression studies. The techniques' principles are similar to the ones used for x-ray computed tomography and are based on the approximation of negligible light scattering in optically cleared samples. The optical clearing is achieved by a chemical procedure which aims at substituting the cellular fluids within the sample with a cell membranes' index matching solution. Once cleared the sample presents very low scattering and is then illuminated with a light collimated beam whose intensity is captured in transillumination mode by a CCD camera. Different projection images of the sample are subsequently obtained over a 360 0 full rotation, and a standard backprojection algorithm can be used in a similar fashion as for x-ray tomography in order to obtain absorption maps. Because not all biological samples present significant absorption contrast, it is not always possible to obtain projections with a good signal-to-noise ratio, a condition necessary to achieve high-quality tomographic reconstructions. Such is the case for example, for early stage's embryos. In this work we demonstrate how, through the use of a random noise removal algorithm, the image quality of the reconstructions can be considerably improved even when the noise is strongly present in the acquired projections. Specifically, we implemented a block matching 3D (BM3D) filter applying it separately on each acquired transillumination projection before performing a complete three-dimensional tomographical reconstruction. To test the efficiency of the adopted filtering scheme, a phantom and a real biological sample were processed. In both cases, the BM3D filter led to a signal-to-noise ratio increment of over 30 d

  12. 3 dimensional modelling of early human brain development using optical projection tomography

    Directory of Open Access Journals (Sweden)

    Strachan Tom

    2004-08-01

    Full Text Available Abstract Background As development proceeds the human embryo attains an ever more complex three dimensional (3D structure. Analyzing the gene expression patterns that underlie these changes and interpreting their significance depends on identifying the anatomical structures to which they map and following these patterns in developing 3D structures over time. The difficulty of this task greatly increases as more gene expression patterns are added, particularly in organs with complex 3D structures such as the brain. Optical Projection Tomography (OPT is a new technology which has been developed for rapidly generating digital 3D models of intact specimens. We have assessed the resolution of unstained neuronal structures within a Carnegie Stage (CS17 OPT model and tested its use as a framework onto which anatomical structures can be defined and gene expression data mapped. Results Resolution of the OPT models was assessed by comparison of digital sections with physical sections stained, either with haematoxylin and eosin (H&E or by immunocytochemistry for GAP43 or PAX6, to identify specific anatomical features. Despite the 3D models being of unstained tissue, peripheral nervous system structures from the trigeminal ganglion (~300 μm by ~150 μm to the rootlets of cranial nerve XII (~20 μm in diameter were clearly identifiable, as were structures in the developing neural tube such as the zona limitans intrathalamica (core is ~30 μm thick. Fourteen anatomical domains have been identified and visualised within the CS17 model. Two 3D gene expression domains, known to be defined by Pax6 expression in the mouse, were clearly visible when PAX6 data from 2D sections were mapped to the CS17 model. The feasibility of applying the OPT technology to all stages from CS12 to CS23, which encompasses the major period of organogenesis for the human developing central nervous system, was successfully demonstrated. Conclusion In the CS17 model considerable detail

  13. The MOZART Project - MOZAmbique Rift Tomography

    Science.gov (United States)

    Fonseca, J. F.; Chamussa, J. R.; Domingues, A.; Helffrich, G. R.; Fishwick, S.; Ferreira, A. M.; Custodio, S.; Brisbourne, A. M.; Grobbelaar, M.

    2012-12-01

    Project MOZART (MOZAmbique Rift Tomography) is an ongoing joint effort of Portuguese, Mozambican and British research groups to investigate the geological structure and current tectonic activity of the southernmost tip of the East African Rift System (EARS) through the deployment of a network of 30 broad band seismic stations in Central and Southern Mozambique. In contrast with other stretches of the EARS to the North and with the Kapvaal craton to the West and South, the lithosphere of Mozambique was not previously studied with a dense seismographic deployment on account of past political instability, and many questions remain unanswered with respect to the location and characteristics of the EARS to the south of Tanzania. In recent years, space geodesy revealed the existence of three microplates in and off Mozambique - Victoria, Rovuma, Lwandle - whose borders provide a connection of the EARS to the South West Indian Ridge as required by plate tectonics. However, the picture is still coarse concerning the location of the rift structures. The 2006 M7 Machaze earthquake in Central Mozambique highlighted the current tectonic activity of the region and added a further clue to the location of the continental rift, prompting the MOZART deployment. Besides helping unravel the current tectonics, the project is expected to shed light on the poorly known Mesoproterozoic structure described by Arthur Holmes in 1951 as the Mozambique Belt, and on the mechanisms of transition from stable craton to rifted continental crust, through the development of a tomographic model for the lithosphere. The MOZART network is distributed South of the Zambezi river at average inter-station spaces of the order of 100 km and includes four stations across the border in South Africa. Data exchange was agreed with AfricaArray. The deployment proceeded in two phases in March 2011, and November and December 2011. Decommissioning is foreseen for August 2013. We report preliminary results for this

  14. SDART: An algorithm for discrete tomography from noisy projections

    NARCIS (Netherlands)

    F. Bleichrodt (Folkert); F. Tabak (Frank); K.J. Batenburg (Joost)

    2014-01-01

    htmlabstractComputed tomography is a noninvasive technique for reconstructing an object from projection data. If the object consists of only a few materials, discrete tomography allows us to use prior knowledge of the gray values corresponding to these materials to improve the accuracy of the

  15. Three-dimensional imaging analysis of Yersinia ruckeri infected rainbow trout (Oncorhynchus mykiss) gills by optical projection tomography

    DEFF Research Database (Denmark)

    Otani, Maki; Raida, Martin Kristian

    Optical projection tomography (OPT) is a new tool for three-dimensional (3D) imaging of small tissues or embryos, based on multi-angle recording of internal fluorescent signals using intact whole mount tissue or fish. To understand the route of infection, gills of Y. ruckeri infected rainbow trout...... were labeled with fluorescent antibody and visualized in 3D by the OPT scanner. Rainbow trout were infected with Y. ruckeri O1 biotype 1 (1 x 109 cells/ml) for 1 hour at 18 °C, and then transferred to clean water. Three fish were sampled at 12 different time points and fixed in 4% PFA. The gills were...... incubated whole with rabbit anti-Y. ruckeri polyclonal antibody and Alexa Fluor®594 conjugated goat anti-rabbit IgG. After embedding in 1% low melting point agarose, specimens were dehydrated in 100% methanol and cleared in BABB (benzyl alcohol: benzyl benzoate) for OPT scanning. 3D imaging results showed...

  16. Multiple projection optical diffusion tomography with plane wave illumination

    International Nuclear Information System (INIS)

    Markel, Vadim A; Schotland, John C

    2005-01-01

    We describe a new data collection scheme for optical diffusion tomography in which plane wave illumination is combined with multiple projections in the slab imaging geometry. Multiple projection measurements are performed by rotating the slab around the sample. The advantage of the proposed method is that the measured data are more compatible with the dynamic range of most commonly used detectors. At the same time, multiple projections improve image quality by mutually interchanging the depth and transverse directions, and the scanned (detection) and integrated (illumination) surfaces. Inversion methods are derived for image reconstructions with extremely large data sets. Numerical simulations are performed for fixed and rotated slabs

  17. Image reconstruction technique using projection data from neutron tomography system

    Directory of Open Access Journals (Sweden)

    Waleed Abd el Bar

    2015-12-01

    Full Text Available Neutron tomography is a very powerful technique for nondestructive evaluation of heavy industrial components as well as for soft hydrogenous materials enclosed in heavy metals which are usually difficult to image using X-rays. Due to the properties of the image acquisition system, the projection images are distorted by several artifacts, and these reduce the quality of the reconstruction. In order to eliminate these harmful effects the projection images should be corrected before reconstruction. This paper gives a description of a filter back projection (FBP technique, which is used for reconstruction of projected data obtained from transmission measurements by neutron tomography system We demonstrated the use of spatial Discrete Fourier Transform (DFT and the 2D Inverse DFT in the formulation of the method, and outlined the theory of reconstruction of a 2D neutron image from a sequence of 1D projections taken at different angles between 0 and π in MATLAB environment. Projections are generated by applying the Radon transform to the original image at different angles.

  18. Tomography

    International Nuclear Information System (INIS)

    Barrett, H.H.; Gordon, S.; Swindell, W.

    1980-01-01

    Apparatus is described for generating a two-dimensional back-projected image of a slice of an object in tomography. The apparatus uses optical techniques to perform the functions of filtering and back projection. Central to the technique is a cylindrical drum which rotates at a fast rate and whose rotational axis tilts at a slower rate. The novel method overcomes the problem of image blurring due to motion which occurs in many tomographic techniques. It also has the advantages of being less expensive and simpler compared to tomography using digital processing techniques which require fast computers. (UK)

  19. Projection neuron circuits resolved using correlative array tomography

    Directory of Open Access Journals (Sweden)

    Daniele eOberti

    2011-04-01

    Full Text Available Assessment of three-dimensional morphological structure and synaptic connectivity is essential for a comprehensive understanding of neural processes controlling behavior. Different microscopy approaches have been proposed based on light microcopy (LM, electron microscopy (EM, or a combination of both. Correlative array tomography (CAT is a technique in which arrays of ultrathin serial sections are repeatedly stained with fluorescent antibodies against synaptic molecules and neurotransmitters and imaged with LM and EM (Micheva and Smith, 2007. The utility of this correlative approach is limited by the ability to preserve fluorescence and antigenicity on the one hand, and EM tissue ultrastructure on the other. We demonstrate tissue staining and fixation protocols and a workflow that yield an excellent compromise between these multimodal imaging constraints. We adapt CAT for the study of projection neurons between different vocal brain regions in the songbird. We inject fluorescent tracers of different colors into afferent and efferent areas of HVC in zebra finches. Fluorescence of some tracers is lost during tissue preparation but recovered using anti-dye antibodies. Synapses are identified in EM imagery based on their morphology and ultrastructure and classified into projection neuron type based on fluorescence signal. Our adaptation of array tomography, involving the use of fluorescent tracers and heavy-metal rich staining and embedding protocols for high membrane contrast in EM will be useful for research aimed at statistically describing connectivity between different projection neuron types and for elucidating how sensory signals are routed in the brain and transformed into a meaningful motor output.

  20. Reconstruction for limited-projection fluorescence molecular tomography based on projected restarted conjugate gradient normal residual.

    Science.gov (United States)

    Cao, Xu; Zhang, Bin; Liu, Fei; Wang, Xin; Bai, Jing

    2011-12-01

    Limited-projection fluorescence molecular tomography (FMT) can greatly reduce the acquisition time, which is suitable for resolving fast biology processes in vivo but suffers from severe ill-posedness because of the reconstruction using only limited projections. To overcome the severe ill-posedness, we report a reconstruction method based on the projected restarted conjugate gradient normal residual. The reconstruction results of two phantom experiments demonstrate that the proposed method is feasible for limited-projection FMT. © 2011 Optical Society of America

  1. Projection model for flame chemiluminescence tomography based on lens imaging

    Science.gov (United States)

    Wan, Minggang; Zhuang, Jihui

    2018-04-01

    For flame chemiluminescence tomography (FCT) based on lens imaging, the projection model is essential because it formulates the mathematical relation between the flame projections captured by cameras and the chemiluminescence field, and, through this relation, the field is reconstructed. This work proposed the blurry-spot (BS) model, which takes more universal assumptions and has higher accuracy than the widely applied line-of-sight model. By combining the geometrical camera model and the thin-lens equation, the BS model takes into account perspective effect of the camera lens; by combining ray-tracing technique and Monte Carlo simulation, it also considers inhomogeneous distribution of captured radiance on the image plane. Performance of these two models in FCT was numerically compared, and results showed that using the BS model could lead to better reconstruction quality in wider application ranges.

  2. Analytical simulation platform describing projections in computed tomography systems

    International Nuclear Information System (INIS)

    Youn, Hanbean; Kim, Ho Kyung

    2013-01-01

    To reduce the patient dose, several approaches such as spectral imaging using photon counting detectors and statistical image reconstruction, are being considered. Although image-reconstruction algorithms may significantly enhance image quality in reconstructed images with low dose, true signal-to-noise properties are mainly determined by image quality in projections. We are developing an analytical simulation platform describing projections to investigate how quantum-interaction physics in each component configuring CT systems affect image quality in projections. This simulator will be very useful for an improved design or optimization of CT systems in economy as well as the development of novel image-reconstruction algorithms. In this study, we present the progress of development of the simulation platform with an emphasis on the theoretical framework describing the generation of projection data. We have prepared the analytical simulation platform describing projections in computed tomography systems. The remained further study before the meeting includes the following: Each stage in the cascaded signal-transfer model for obtaining projections will be validated by the Monte Carlo simulations. We will build up energy-dependent scatter and pixel-crosstalk kernels, and show their effects on image quality in projections and reconstructed images. We will investigate the effects of projections obtained from various imaging conditions and system (or detector) operation parameters on reconstructed images. It is challenging to include the interaction physics due to photon-counting detectors into the simulation platform. Detailed descriptions of the simulator will be presented with discussions on its performance and limitation as well as Monte Carlo validations. Computational cost will also be addressed in detail. The proposed method in this study is simple and can be used conveniently in lab environment

  3. Default options and social welfare : Opt in versus opt out

    NARCIS (Netherlands)

    Bouckaert, J.M.C.; Degryse, H.A.

    2013-01-01

    We offer a social-welfare comparison of the two most prominent default options – opt in and opt out – using a two-period model of localized competition. We demonstrate that when consumers stick to the default option, the prevailing default policy shapes firms' ability to collect and use customer

  4. Ultrasonic computerized tomography (CT) for temperature measurements with limited projection data based on extrapolated filtered back projection (FBP) method

    International Nuclear Information System (INIS)

    Zhu Ning; Jiang Yong; Kato, Seizo

    2005-01-01

    This study uses ultrasound in combination with tomography to obtain three-dimensional temperature measurements using projection data obtained from limited projection angle. The main feature of the new computerized tomography (CT) reconstruction algorithm is to employ extrapolation scheme to make up for the incomplete projection data, it is based on the conventional filtered back projection (FBP) method while on top of that taking into account the correlation between the projection data and Fourier transform-based extrapolation. Computer simulation is conducted to verify the above algorithm. An experimental 3D temperature distribution measurement is also carried out to validate the proposed algorithm. The simulation and experimental results demonstrate that the extrapolated FBP CT algorithm is highly effective in dealing with projection data from limited projection angle

  5. Neutron tomography using projection data obtained by Monte Carlo simulation for nondestructive evaluation

    International Nuclear Information System (INIS)

    Silva, A.X. da; Crispim, V.R.

    2002-01-01

    This work present the application of a computer package for generating of projection data for neutron computerized tomography, and in second part, discusses an application of neutron tomography, using the projection data obtained by Monte Carlo technique, for the detection and localization of light materials such as those containing hydrogen, concealed by heavy materials such as iron and lead. For tomographic reconstructions of the samples simulated use was made of only six equal projection angles distributed between 0 deg C and 180 deg C, with reconstruction making use of an algorithm (ARIEM), based on the principle of maximum entropy. With the neutron tomography it was possible to detect and locate polyethylene and water hidden by lead and iron (with 1 cm-thick). Thus, it is demonstrated that thermal neutrons tomography is a viable test method which can provide important interior information about test components, so, extremely useful in routine industrial applications.(author)

  6. Improving limited-projection-angle fluorescence molecular tomography using a co-registered x-ray computed tomography scan.

    Science.gov (United States)

    Radrich, Karin; Ale, Angelique; Ermolayev, Vladimir; Ntziachristos, Vasilis

    2012-12-01

    We examine the improvement in imaging performance, such as axial resolution and signal localization, when employing limited-projection-angle fluorescence molecular tomography (FMT) together with x-ray computed tomography (XCT) measurements versus stand-alone FMT. For this purpose, we employed living mice, bearing a spontaneous lung tumor model, and imaged them with FMT and XCT under identical geometrical conditions using fluorescent probes for cancer targeting. The XCT data was employed, herein, as structural prior information to guide the FMT reconstruction. Gold standard images were provided by fluorescence images of mouse cryoslices, providing the ground truth in fluorescence bio-distribution. Upon comparison of FMT images versus images reconstructed using hybrid FMT and XCT data, we demonstrate marked improvements in image accuracy. This work relates to currently disseminated FMT systems, using limited projection scans, and can be employed to enhance their performance.

  7. The utility of three-dimensional optical projection tomography in nerve injection injury imaging

    Czech Academy of Sciences Publication Activity Database

    Cvetko, E.; Čapek, Martin; Damjanovska, M.; Reina, M. A.; Eržen, I.; Stopar-Pintarič, T.

    2015-01-01

    Roč. 70, č. 8 (2015), s. 939-947 ISSN 0003-2409 R&D Projects: GA ČR(CZ) GA13-12412S; GA MŠk(CZ) LH13028 Institutional support: RVO:67985823 Keywords : optical projection tomography * 3D nerve visualization * nerve disruption Subject RIV: EA - Cell Biology Impact factor: 3.794, year: 2015

  8. Image reconstruction from projections and its application in emission computer tomography

    International Nuclear Information System (INIS)

    Kuba, Attila; Csernay, Laszlo

    1989-01-01

    Computer tomography is an imaging technique for producing cross sectional images by reconstruction from projections. Its two main branches are called transmission and emission computer tomography, TCT and ECT, resp. After an overview of the theory and practice of TCT and ECT, the first Hungarian ECT type MB 9300 SPECT consisting of a gamma camera and Ketronic Medax N computer is described, and its applications to radiological patient observations are discussed briefly. (R.P.) 28 refs.; 4 figs

  9. No opt-out is forever. Sweden opts back in

    International Nuclear Information System (INIS)

    Schneider, Horst

    2010-01-01

    The draft legislation by the conservative-liberal Swedish government of early 2010, which was adopted by the Swedish parliament on June 17, 2010, not only repeals the shutdown of all Swedish nuclear power plants, which had earlier been foreseen by this year, but permits the construction and operation of new plants. In Sweden, a referendum in 1980 started the opt-out process. Shutdown within 30 years was foreseen in the regulation. As early as in late 1995, an Energy Committee appointed by the government reported that a complete opt-out by 2010 was impossible to achieve on economic and environmental grounds. Under the 1997 Opt-out Act, the government may shut down nuclear power plants at any time against an indemnification - unlike Germany. Another prerequisite is the realistic availability of new energy sources. As a consequence, only 2 nuclear power plants have been shut down so far, mainly because of protests from neighboring Denmark. Thirty years after the referendum, the acceptance of nuclear power in Sweden is high and stable. In line with growing public acceptance in the course of the debate about climate change, the Christian-Democratic Party changed its policy in March 2007, opting out of the opt-out. Finally, the conservative-liberal Swedish government submitted draft legislation to parliament which also permitted building new nuclear power plants. The Social Democratic Workers' Party, which is in the opposition, stuck to its rejection of the use of nuclear power and announced its intention to reverse the repeal of the opt-out in September 2010, after parliamentary elections and a possible new red-green government. The public and political developments in Sweden show that social attitudes towards nuclear power, opt-out policies and legal regulations can change. Adopting a rational attitude when discussing nuclear power and realities is possible, and political views sooner or later will adapt to the new situation. This could happen also in Germany

  10. The Diplomacy of Opting Out

    DEFF Research Database (Denmark)

    Adler-Nissen, Rebecca

    and Home Affairs. Theoretically, the study offers a political sociology of European integration, which is seen as driven by politico-administrative struggling for capital in quasi-autonomous fields. This approach can be used more generally by EU and IR scholars to understand social dynamics of inclusion...... to upholding a doxa of ‘ever closer union among the peoples of Europe'. Empirically, the thesis provides the first extensive study of the diplomatic practices of the two champions of opting out - the UK and Denmark - when they handle their most important opt-outs from the Economic Monetary Union and Justice...... the everyday social setting of international and regional governance....

  11. The muon tomography Diaphane project : recent upgrades and measurements

    Science.gov (United States)

    Jourde, Kevin; Gibert, Dominique; Marteau, Jacques; de Bremond d'Ars, Jean; Gardien, Serge; Girerd, Claude; Ianigro, Jean-Christophe; Carbone, Daniele

    2014-05-01

    Muon tomography measures the flux of cosmic muons crossing geological bodies to determine their density. Large density heterogeneities were detected on la Soufrière de Guadeloupe revealing its very active phreatic system. These measurements were made possible thanks to electronic and signal processing developments. Indeed the telescopes used to perform these measurements are exposed to noise fluxes with high intensities relative to the tiny flux of interest. A high precision clock permitted to measure upward-going particles coming from the rear of the telescope that used to mix with the volcano signal. Also the particles energy deposit inside the telescope shows that other particles than muons take part to the noise. We present data acquired on la Soufrière, mount Etna in Italy, and in the Mont Terri tunnel in Switzerland. Biases produced on density muon radiographies are quantified and correction procedures are applied.

  12. Tomography

    International Nuclear Information System (INIS)

    1985-01-01

    Already widely accepted in medicine, tomography can also be useful in industry. The theory behind tomography and a demonstration of the technique to inspect a motorcycle carburetor is presented. To demonstrate the potential of computer assisted tomography (CAT) to accurately locate defects in three dimensions, a sectioned 5 cm gate valve with a shrink cavity made visible by the sectioning was tomographically imaged using a Co-60 source. The tomographic images revealed a larger cavity below the sectioned surface. The position of this cavity was located with an in-plane and axial precision of approximately +-1 mm. The volume of the cavity was estimated to be approximately 40 mm 3

  13. Analytically derived weighting factors for transmission tomography cone beam projections

    International Nuclear Information System (INIS)

    Yao Weiguang; Leszczynski, Konrad

    2009-01-01

    Weighting factors, which define the contributions of individual voxels of a 3D object to individual projection elements (pixels) on the detector, are the basic elements required in iterative tomographic reconstructions from transmission projections. Exact or as accurate as possible values for weighting factors are required in high-resolution reconstructions. Geometric complexity of the problem, however, makes it difficult to obtain exact weighting factor values. In this work, we derive an analytical expression for the weighting factors in cone beam projection geometry. The resulting formula is validated and applied to reconstruction from mega and kilovoltage x-ray cone beam projections. The reconstruction speed and accuracy are significantly improved by using the weighting factor values.

  14. Effect of quantization and interpolation of projections on the sensitivity of computerized tomography

    International Nuclear Information System (INIS)

    Vajnberg, Eh.I.; Fajngojz, M.L.

    1984-01-01

    The sources and forms of manifestation of errors in quantization and interpolation of projections in case of X-ray computerized tomography are considered and quantitative criteria of their evaluation are formulated. The dominating role of the interaction of two successive quantizations of projections - one-dimensional and two-dimensional ones is revealed. The necessity of joint optimization of the two-dimensional quantization range, expansion and form of interpolation function, quantized convolution nucleus is substantiated. The experimental results at aspect ratio of tomograms 256x256 and 480 projections are presented

  15. Tomography

    International Nuclear Information System (INIS)

    Allan, C.J.; Keller, N.A.; Lupton, L.R.; Taylor, T.; Tonner, P.D.

    1984-10-01

    Tomography is a non-intrusive imaging technique being developed at CRNL as an industrial tool for generating quantitative cross-sectional density maps of objects. Of most interest is tomography's ability to: distinguish features within complex geometries where other NDT techniques fail because of the complexity of the geometry; detect/locate small density changes/defects within objects, e.g. void fraction measurements within thick-walled vessels, shrink cavities in castings, etc.; provide quantitative data that can be used in analyses, e.g. of complex processes, or fracture mechanics; and provide objective quantitative data that can be used for (computer-based) quality assurance decisions, thereby reducing and in some cases eliminating the present subjectivity often encountered in NDT. The CRNL program is reviewed and examples are presented to illustrate the potential and the limitations of the technology

  16. Generalized algorithm for X-ray projections generation in cone-beam tomography

    International Nuclear Information System (INIS)

    Qin Zhongyuan; Mu Xuanqin; Wang Ping; Cai Yuanlong; Hou Chuanjian

    2002-01-01

    In order to get rid of random factors in the measurement so as to support proceeding 3D reconstruction, a general approach is presented to obtain the X-ray projections in cone-beam tomography. The phantom is firstly discretized into cubic volume through inverse transformation then a generalized projection procedure is proposed to the digitized result without concerning what the phantom exactly is. In the second step, line integrals are calculated to obtain the projection of each X-ray through accumulation of tri-linear interpolation. Considering projection angles, a rotation matrix is proposed to the X-ray source and the detector plane so projections in arbitrary angles can be got. In this approach the algorithm is easy to be extended and irregular objects can also be processed. The algorithm is implemented in Visual C++ and experiments are done using different models. Satisfactory results are obtained. It makes good preparation for the proceeding reconstruction

  17. A reconstruction algorithm for coherent scatter computed tomography based on filtered back-projection

    International Nuclear Information System (INIS)

    Stevendaal, U. van; Schlomka, J.-P.; Harding, A.; Grass, M.

    2003-01-01

    Coherent scatter computed tomography (CSCT) is a reconstructive x-ray imaging technique that yields the spatially resolved coherent-scatter form factor of the investigated object. Reconstruction from coherently scattered x-rays is commonly done using algebraic reconstruction techniques (ART). In this paper, we propose an alternative approach based on filtered back-projection. For the first time, a three-dimensional (3D) filtered back-projection technique using curved 3D back-projection lines is applied to two-dimensional coherent scatter projection data. The proposed algorithm is tested with simulated projection data as well as with projection data acquired with a demonstrator setup similar to a multi-line CT scanner geometry. While yielding comparable image quality as ART reconstruction, the modified 3D filtered back-projection algorithm is about two orders of magnitude faster. In contrast to iterative reconstruction schemes, it has the advantage that subfield-of-view reconstruction becomes feasible. This allows a selective reconstruction of the coherent-scatter form factor for a region of interest. The proposed modified 3D filtered back-projection algorithm is a powerful reconstruction technique to be implemented in a CSCT scanning system. This method gives coherent scatter CT the potential of becoming a competitive modality for medical imaging or nondestructive testing

  18. 16 CFR 313.7 - Form of opt out notice to consumers; opt out methods.

    Science.gov (United States)

    2010-01-01

    ... your consumers that accurately explains the right to opt out under that section. The notice must state... consumer to a nonaffiliated third party; (ii) That the consumer has the right to opt out of that disclosure; and (iii) A reasonable means by which the consumer may exercise the opt out right. (2) Examples—(i...

  19. 12 CFR 332.7 - Form of opt out notice to consumers; opt out methods.

    Science.gov (United States)

    2010-01-01

    ... each of your consumers that accurately explains the right to opt out under that section. The notice... your consumer to a nonaffiliated third party; (ii) That the consumer has the right to opt out of that disclosure; and (iii) A reasonable means by which the consumer may exercise the opt out right. (2) Examples...

  20. 12 CFR 216.7 - Form of opt out notice to consumers; opt out methods.

    Science.gov (United States)

    2010-01-01

    ... each of your consumers that accurately explains the right to opt out under that section. The notice... your consumer to a nonaffiliated third party; (ii) That the consumer has the right to opt out of that disclosure; and (iii) A reasonable means by which the consumer may exercise the opt out right. (2) Examples...

  1. 12 CFR 573.7 - Form of opt out notice to consumers; opt out methods.

    Science.gov (United States)

    2010-01-01

    ... reserve the right to disclose nonpublic personal information about your consumer to a nonaffiliated third party; (ii) That the consumer has the right to opt out of that disclosure; and (iii) A reasonable means by which the consumer may exercise the opt out right. (2) Examples—(i) Adequate opt out notice. You...

  2. 12 CFR 40.7 - Form of opt out notice to consumers; opt out methods.

    Science.gov (United States)

    2010-01-01

    ... discloses or reserves the right to disclose nonpublic personal information about its consumer to a nonaffiliated third party; (ii) That the consumer has the right to opt out of that disclosure; and (iii) A reasonable means by which the consumer may exercise the opt out right. (2) Examples. (i) Adequate opt out...

  3. 12 CFR 716.7 - Form of opt out notice to consumers and opt out methods.

    Science.gov (United States)

    2010-01-01

    ... your consumers that accurately explains the right to opt out under that section. The notice must state... consumer to a nonaffiliated third party; (ii) That the consumer has the right to opt out of that disclosure; and (iii) A reasonable means by which the consumer may exercise the opt out right. (2) Examples. (i...

  4. 17 CFR 248.7 - Form of opt out notice to consumers; opt out methods.

    Science.gov (United States)

    2010-04-01

    ... the right to disclose nonpublic personal information about your consumer to a nonaffiliated third party; (ii) That the consumer has the right to opt out of that disclosure; and (iii) A reasonable means by which the consumer may exercise the opt out right. (2) Examples—(i) Adequate opt out notice. You...

  5. The rise and fall of an opt-out system.

    Science.gov (United States)

    Nordfalk, Francisca; Hoeyer, Klaus

    2018-04-01

    In Denmark, citizens participate in register-based research without the possibility of opting out. However, in 1995 it was made possible for Danish citizens to register an opt-out called 'researcher protection' [ forskerbeskyttelse], which implied that researchers could not contact people to invite them to participate in research projects, such as clinical trials or questionnaries, based on their registrations in national registers. Data already registered could still be used for research. In 2014, this possibility of opt-out was revoked by law. The aims of this paper are to understand how the Danish researcher protection system came about, why it was terminated and what we can we learn from this example. We conducted a descriptive analysis of a copy of the former researcher protection register along with policies and media debate surrounding the rise and revocation of the researcher protection system. Our results show how both the inception and the abolishment of researcher protection appear to be ad hoc and without specified criteria of success. An examination of the recorded entries in the researcher protection registry could have led to changes in its administration as an alternative to its total abolition. In future opt-out systems, there should be focus on monitoring register practices and the purpose and criteria for evaluation must be defined prior to implementation.

  6. Tomography

    International Nuclear Information System (INIS)

    Brown, B.H.; Barber, D.C.; Freeston, I.L.

    1983-01-01

    Tomography images of a body are constructed by placing a plurality of surface electrodes at spaced intervals on the body, causing currents to flow in the body (e.g. by applying a potential between each pair of electrodes in turn, or by induction), and measuring the potential between pairs of electrodes, calculating the potential expected in each case on the assumption that the body consists of a medium of uniform impedance, plotting the isopotentials corresponding to the calculated results to create a uniform image of the body, obtaining the ratio between the measured potential and the calculated potential in each case, and modifying the image in accordance with the respective ratios by increasing the assumed impedance along an isopotential in proportion to a ratio greater than unity or decreasing the assumed impedance in proportion to a ratio less than unity. The modified impedances along the isopotentials for each pair of electrodes are superimposed. The calculations are carried out using a computer and the plotting is carried out by a visual display unit and/or a print-out unit. (author)

  7. X-ray phase radiography and tomography with grating interferometry and the reverse projection technique

    International Nuclear Information System (INIS)

    Wang, Zhili; Gao, Kun; Ge, Xin; Wu, Zhao; Chen, Heng; Wang, Shenghao; Wu, Ziyu; Zhu, Peiping; Yuan, Qingxi; Huang, Wanxia; Zhang, Kai

    2013-01-01

    X-ray grating interferometry provides substantially increased contrast over conventional absorption-based imaging methods, and therefore new and complementary information. Compared with other phase-contrast imaging techniques, x-ray grating interferometry can overcome some of the problems that have impaired the applications of x-ray phase-contrast radiography and phase tomography. Recently, special attention has been paid to the development of quantitative phase retrieval methods, which is mandatory to perform x-ray phase tomography, to achieve material identification, to differentiate distinct tissues, etc. Typically, the phase-stepping approach has been utilized for phase retrieval in grating interferometry. This method requires a grating scanning and acquisition of multiple radiographic projections, and therefore is disadvantageous in terms of imaging speed and radiation damage. Here we present an innovative, highly sensitive approach, dubbed ‘reverse projection’ (RP), for quantitative phase retrieval. Compared with the phase-stepping approach, the present RP method abandons grating scanning completely, and thus is advantageous due to its much higher efficiency and the reduced radiation dose, without the degradation of reconstruction quality. This review presents a detailed explanation of the principle of the RP method. Both radiography and phase tomography experiments are performed to validate the RP method. We believe that this new technique will find widespread applications in biomedical imaging and in vivo studies. (paper)

  8. Opting Out of the European Union

    DEFF Research Database (Denmark)

    Adler-Nissen, Rebecca

    controversial cases of differentiated integration: the British and Danish opt-outs from Economic and Monetary Union and European policies on borders, asylum, migration, internal security and justice. Drawing on over one hundred interviews with national representatives and EU officials, the author demonstrates......European integration continues to deepen despite major crises and attempts to take back sovereignty. A growing number of member states are reacting to a more constraining EU by negotiating opt-outs. This book provides the first in-depth account of how opt-outs work in practice. It examines the most...... how representatives manage the stigma of opting out, allowing them to influence even politically sensitive areas covered by their opt-outs. Developing a practice approach to European integration, the book shows how everyday negotiations transform national interests into European ideals. It is usually...

  9. Calient Networks chosen as core platform for OptIPuter

    CERN Multimedia

    2003-01-01

    Calient Networks, a provider of intelligent all-optical switching systems and software, will team with the California Institute for Telecommunications and Information Technology (Cal-(IT)2) and the University of Illinois at Chicago (UIC) on development of the "OptIPuter,". This is a powerful distributed cyber-infrastructure project designed to support data-intensive scientific research and collaboration (1/2 page).

  10. Total Variation-Based Reduction of Streak Artifacts, Ring Artifacts and Noise in 3D Reconstruction from Optical Projection Tomography

    Czech Academy of Sciences Publication Activity Database

    Michálek, Jan

    2015-01-01

    Roč. 21, č. 6 (2015), s. 1602-1615 ISSN 1431-9276 R&D Projects: GA MŠk(CZ) LH13028; GA ČR(CZ) GA13-12412S Institutional support: RVO:67985823 Keywords : optical projection tomography * microscopy * artifacts * total variation * data mismatch Subject RIV: EA - Cell Biology Impact factor: 1.730, year: 2015

  11. Projection matrix acquisition for cone-beam computed tomography iterative reconstruction

    Science.gov (United States)

    Yang, Fuqiang; Zhang, Dinghua; Huang, Kuidong; Shi, Wenlong; Zhang, Caixin; Gao, Zongzhao

    2017-02-01

    Projection matrix is an essential and time-consuming part in computed tomography (CT) iterative reconstruction. In this article a novel calculation algorithm of three-dimensional (3D) projection matrix is proposed to quickly acquire the matrix for cone-beam CT (CBCT). The CT data needed to be reconstructed is considered as consisting of the three orthogonal sets of equally spaced and parallel planes, rather than the individual voxels. After getting the intersections the rays with the surfaces of the voxels, the coordinate points and vertex is compared to obtain the index value that the ray traversed. Without considering ray-slope to voxel, it just need comparing the position of two points. Finally, the computer simulation is used to verify the effectiveness of the algorithm.

  12. submitter The Muon Portal Project: Design and construction of a scanning portal based on muon tomography

    CERN Document Server

    Antonuccio, V; Becciani, U; Bonanno, D L; Bonanno, G; Bongiovanni, D; Fallica, P G; Garozzo, S; Grillo, A; La Rocca, P; Leonora, E; Longhitano, F; Lo Presti, D; Marano, D; Parasole, O; Pugliatti, C; Randazzo, N; Riggi, F; Riggi, S; Romeo, G; Romeo, M; Russo, G V; Santagati, G; Timpanaro, M C; Valvo, G

    2017-01-01

    Cosmic ray tomography is a technique which exploits the multiple Coulomb scattering of highly penetrating cosmic ray-produced muons to perform non-destructive inspection of high-Z materials without the use of artificial radiation. A muon tomography detection system can be used as a portal monitor at border crossing points for detecting illegal targeted objects. The Muon Portal Project is a joint initiative between Italian research and industrial partners, aimed at the construction of a real size detector prototype $(6×3×7 m^3)$ for the inspection of cargo containers by the muon scattering technique. The detector consists of four XY tracking planes, two placed above and two below the container to be inspected. After a research and development phase, which led to the choice and test of the individual components, the construction and installation of the detection modules is almost completed. In this paper the present status of the Project is reported, focusing on the design and construction phase, as well as o...

  13. The Muon Portal Project: Design and construction of a scanning portal based on muon tomography

    Energy Technology Data Exchange (ETDEWEB)

    Antonuccio, V. [INAF - Osservatorio Astrofisico di Catania (Italy); Bandieramonte, M. [CERN, Geneva (Switzerland); Becciani, U. [INAF - Osservatorio Astrofisico di Catania (Italy); Bonanno, D.L., E-mail: danilo.bonanno@ct.infn.it [INFN Sezione di Catania, Catania (Italy); Bonanno, G. [INAF - Osservatorio Astrofisico di Catania (Italy); Bongiovanni, D. [INFN Sezione di Catania, Catania (Italy); Fallica, P.G. [STMicroelectronics, Catania (Italy); Garozzo, S.; Grillo, A. [INAF - Osservatorio Astrofisico di Catania (Italy); La Rocca, P. [INFN Sezione di Catania, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Leonora, E.; Longhitano, F. [INFN Sezione di Catania, Catania (Italy); Lo Presti, D. [INFN Sezione di Catania, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Marano, D. [INAF - Osservatorio Astrofisico di Catania (Italy); Parasole, O. [INFN Sezione di Catania, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Pugliatti, C. [Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Randazzo, N. [INFN Sezione di Catania, Catania (Italy); Riggi, F. [INFN Sezione di Catania, Catania (Italy); Dipartimento di Fisica e Astronomia, Università di Catania, Catania (Italy); Riggi, S. [INAF - Osservatorio Astrofisico di Catania (Italy); INFN Sezione di Catania, Catania (Italy); Romeo, G. [INAF - Osservatorio Astrofisico di Catania (Italy); and others

    2017-02-11

    Cosmic ray tomography is a technique which exploits the multiple Coulomb scattering of highly penetrating cosmic ray-produced muons to perform non-destructive inspection of high-Z materials without the use of artificial radiation. A muon tomography detection system can be used as a portal monitor at border crossing points for detecting illegal targeted objects. The Muon Portal Project is a joint initiative between Italian research and industrial partners, aimed at the construction of a real size detector prototype (6×3×7 m{sup 3}) for the inspection of cargo containers by the muon scattering technique. The detector consists of four XY tracking planes, two placed above and two below the container to be inspected. After a research and development phase, which led to the choice and test of the individual components, the construction and installation of the detection modules is almost completed. In this paper the present status of the Project is reported, focusing on the design and construction phase, as well as on the preliminary results obtained with the first detection planes.

  14. The Muon Portal Project: Design and construction of a scanning portal based on muon tomography

    Science.gov (United States)

    Antonuccio, V.; Bandieramonte, M.; Becciani, U.; Bonanno, D. L.; Bonanno, G.; Bongiovanni, D.; Fallica, P. G.; Garozzo, S.; Grillo, A.; La Rocca, P.; Leonora, E.; Longhitano, F.; Lo Presti, D.; Marano, D.; Parasole, O.; Pugliatti, C.; Randazzo, N.; Riggi, F.; Riggi, S.; Romeo, G.; Romeo, M.; Russo, G. V.; Santagati, G.; Timpanaro, M. C.; Valvo, G.

    2017-02-01

    Cosmic ray tomography is a technique which exploits the multiple Coulomb scattering of highly penetrating cosmic ray-produced muons to perform non-destructive inspection of high-Z materials without the use of artificial radiation. A muon tomography detection system can be used as a portal monitor at border crossing points for detecting illegal targeted objects. The Muon Portal Project is a joint initiative between Italian research and industrial partners, aimed at the construction of a real size detector prototype (6×3×7 m3) for the inspection of cargo containers by the muon scattering technique. The detector consists of four XY tracking planes, two placed above and two below the container to be inspected. After a research and development phase, which led to the choice and test of the individual components, the construction and installation of the detection modules is almost completed. In this paper the present status of the Project is reported, focusing on the design and construction phase, as well as on the preliminary results obtained with the first detection planes.

  15. Incomplete projection reconstruction of computed tomography based on the modified discrete algebraic reconstruction technique

    Science.gov (United States)

    Yang, Fuqiang; Zhang, Dinghua; Huang, Kuidong; Gao, Zongzhao; Yang, YaFei

    2018-02-01

    Based on the discrete algebraic reconstruction technique (DART), this study aims to address and test a new improved algorithm applied to incomplete projection data to generate a high quality reconstruction image by reducing the artifacts and noise in computed tomography. For the incomplete projections, an augmented Lagrangian based on compressed sensing is first used in the initial reconstruction for segmentation of the DART to get higher contrast graphics for boundary and non-boundary pixels. Then, the block matching 3D filtering operator was used to suppress the noise and to improve the gray distribution of the reconstructed image. Finally, simulation studies on the polychromatic spectrum were performed to test the performance of the new algorithm. Study results show a significant improvement in the signal-to-noise ratios (SNRs) and average gradients (AGs) of the images reconstructed from incomplete data. The SNRs and AGs of the new images reconstructed by DART-ALBM were on average 30%-40% and 10% higher than the images reconstructed by DART algorithms. Since the improved DART-ALBM algorithm has a better robustness to limited-view reconstruction, which not only makes the edge of the image clear but also makes the gray distribution of non-boundary pixels better, it has the potential to improve image quality from incomplete projections or sparse projections.

  16. Industrial process gamma tomography. Final report of a coordinated research project 2003-2007

    International Nuclear Information System (INIS)

    2008-05-01

    Gamma computed tomography (CT) is complementary to radiotracer and gamma sealed source techniques largely used for analyzing industrial process units. Relevant target areas for gamma CT applications are generally known. Although the methodology is generic and applicable across broad industrial specimen and facilities, a number of specific items have been identified as the most appropriate target beneficiaries of these applications: distillation columns; packed beds; risers; fluidized beds and other multiphase processing units. These industrial process units present significant technical challenges to CT investigations in terms of the complexity of the multiphase flows that occur in them. In order to address these needs, the IAEA implemented a Coordinated Research Project (CRP) on Industrial Process Gamma Tomography with the overall objective of testing and validating CT techniques for diagnosing industrial multiphase processes. CT laboratories from Argentina, Brazil, Czech Republic, France, Republic of Korea, Malaysia, Norway, Poland, United Kingdom and the United States of America have participated. The specific objectives of the CRP were assessment of the tomographic methods, evaluation of them for investigation of multiphase engineering processes, and design of prototypes of simple CT systems for industrial processing, which can be transferred to other developing countries. The CRP has generated an active network, which also included other groups engaged in the CT field. The round robin test has played an important role in validation of techniques and software. This TECDOC is prepared based on the findings and achievements of the CRP. It is a comprehensive technical report containing valuable information, not readily available in any single publication elsewhere. The participants' reports and software developed by them are compiled in a CD-ROM and attached to the back cover. The guidelines and software packages described in this report can be used as an

  17. Inclusion of residual tissue in biobanks: opt-in or opt-out?

    Directory of Open Access Journals (Sweden)

    Noor A A Giesbertz

    Full Text Available Residual samples are an important source of tissue for biobanks. They refer to leftover tissue that is obtained in the course of clinical care. Residual samples can be included through an opt-in method--that is, a person explicitly expresses consent to include residual tissue--or an opt-out method--that is, the tissue is stored unless a person explicitly refuses. At the moment there is a renewed interest in the appropriate method for the inclusion of residual samples in biobanks. The expansion of biobanks and rapid developments in biomedical research underscore the need to evaluate the proper procedure. In this article we revisit the arguments in favor and against opt-in and opt-out methods for residual tissue research. We conclude firstly that an opt-out method is only justifiable when certain conditions are met: (1 awareness has to be raised, (2 sufficient information has to be provided, and (3 a genuine possibility to object has to be offered. An opt-out procedure that fulfills these conditions can be called a "thick" opt-out method. As a consequence, the dichotomy between opt-in and opt-out is less stark than usually suggested, as both methods require a certain amount of effort. Secondly, we conclude that because of the diversity of tissue and research, not every situation can be treated alike. There are at least four situations that require opt-in procedures: (1 research with higher risks or increased burdens, (2 the use of controversial or high-impact techniques, (3 research on sensitive tissue types, and (4 research involving vulnerable patients. We suggest that further interdisciplinary debate should answer the question when to opt-in or when to opt-out.

  18. Opting for co-operation

    International Nuclear Information System (INIS)

    1987-12-01

    This report proposes a process for choosing a low-level radioactive waste management site based on the following principles: the community should volunteer and have the right to opt out of the siting process; the community should be a partner in problem-solving and decision-making throughout the process; the community should receive compensation to offset impacts and enhance local benefits; the community should have the right to select from given technical options and impact management measures; the siting task force responsible for implementation of the process must ensure that environmental safety and human health are not compromised. The Task Force recommends that: voluntary acceptance be adopted as the basic principle for the process of siting a low-level waste management facility; the emphasis given to technical assessments of options and their impacts be counterbalanced by legitimization of an active joint decision-making role for potentially affected residents; the community accepting the facility be compensated in a way that offsets all costs and leaves the community better off than it was previously; the concepts of improved management and long-term storage, with the ability to monitor and retrieve wastes, become the immediate objectives for the handling of low-level radioactive waste accumulations. The Task Force suggests a classification system for wastes based on the fundamental properties of the wastes and their management requirements rather than on their origins and administrative affiliations. The Atomic Energy Control Board should assume a more proactive role in defining and establishing acceptable approaches to low-level radioactive waste management. The Task Force did not discover any evidence that there is a health threat from existing low-level waste accumulations in Ontario. Carbon 14 may pose a particular problem, and there should be further research into the requirements of carbon 14

  19. Detailed Vascular Anatomy of the Human Retina by Projection-Resolved Optical Coherence Tomography Angiography

    Science.gov (United States)

    Campbell, J. P.; Zhang, M.; Hwang, T. S.; Bailey, S. T.; Wilson, D. J.; Jia, Y.; Huang, D.

    2017-02-01

    Optical coherence tomography angiography (OCTA) is a noninvasive method of 3D imaging of the retinal and choroidal circulations. However, vascular depth discrimination is limited by superficial vessels projecting flow signal artifact onto deeper layers. The projection-resolved (PR) OCTA algorithm improves depth resolution by removing projection artifact while retaining in-situ flow signal from real blood vessels in deeper layers. This novel technology allowed us to study the normal retinal vasculature in vivo with better depth resolution than previously possible. Our investigation in normal human volunteers revealed the presence of 2 to 4 distinct vascular plexuses in the retina, depending on location relative to the optic disc and fovea. The vascular pattern in these retinal plexuses and interconnecting layers are consistent with previous histologic studies. Based on these data, we propose an improved system of nomenclature and segmentation boundaries for detailed 3-dimensional retinal vascular anatomy by OCTA. This could serve as a basis for future investigation of both normal retinal anatomy, as well as vascular malformations, nonperfusion, and neovascularization.

  20. An electron tomography algorithm for reconstructing 3D morphology using surface tangents of projected scattering interfaces

    Science.gov (United States)

    Petersen, T. C.; Ringer, S. P.

    2010-03-01

    Upon discerning the mere shape of an imaged object, as portrayed by projected perimeters, the full three-dimensional scattering density may not be of particular interest. In this situation considerable simplifications to the reconstruction problem are possible, allowing calculations based upon geometric principles. Here we describe and provide an algorithm which reconstructs the three-dimensional morphology of specimens from tilt series of images for application to electron tomography. Our algorithm uses a differential approach to infer the intersection of projected tangent lines with surfaces which define boundaries between regions of different scattering densities within and around the perimeters of specimens. Details of the algorithm implementation are given and explained using reconstruction calculations from simulations, which are built into the code. An experimental application of the algorithm to a nano-sized Aluminium tip is also presented to demonstrate practical analysis for a real specimen. Program summaryProgram title: STOMO version 1.0 Catalogue identifier: AEFS_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFS_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 2988 No. of bytes in distributed program, including test data, etc.: 191 605 Distribution format: tar.gz Programming language: C/C++ Computer: PC Operating system: Windows XP RAM: Depends upon the size of experimental data as input, ranging from 200 Mb to 1.5 Gb Supplementary material: Sample output files, for the test run provided, are available. Classification: 7.4, 14 External routines: Dev-C++ ( http://www.bloodshed.net/devcpp.html) Nature of problem: Electron tomography of specimens for which conventional back projection may fail and/or data for which there is a limited angular

  1. Use of a high density lead glass tubing projection chamber in positron emission tomography and in high energy physics

    International Nuclear Information System (INIS)

    Conti, M.; Guerra, A.D.; Habel, R.; Mulera, T.; Perez-Mendez, V.; Schwartz, G.

    1985-10-01

    We describe the principle of operation of a high density Projection Chamber, in which the converter/radiator and drift field shaping structures are combined in the form of high density (5 to 6 g/cm 3 ) lead glass tubing. The main applications of this type of detector to Medical Physics (Positron Emission Tomography) and High Energy Physics (Electromagnetic Calorimetry) are discussed

  2. Correction of computed tomography motion artifacts using pixel-specific back-projection

    International Nuclear Information System (INIS)

    Ritchie, C.J.; Crawford, C.R.; Godwin, J.D.; Kim, Y. King, K.F.

    1996-01-01

    Cardiac and respiratory motion can cause artifacts in computed tomography scans of the chest. The authors describe a new method for reducing these artifacts called pixel-specific back-projection (PSBP). PSBP reduces artifacts caused by in-plane motion by reconstructing each pixel in a frame of reference that moves with the in-plane motion in the volume being scanned. The motion of the frame of reference is specified by constructing maps that describe the motion of each pixel in the image at the time each projection was measured; these maps are based on measurements of the in-plane motion. PSBP has been tested in computer simulations and with volunteer data. In computer simulations, PSBP removed the structured artifacts caused by motion. In scans of two volunteers, PSBP reduced doubling and streaking in chest scans to a level that made the images clinically useful. PSBP corrections of liver scans were less satisfactory because the motion of the liver is predominantly superior-inferior (S-I). PSBP uses a unique set of motion parameters to describe the motion at each point in the chest as opposed to requiring that the motion be described by a single set of parameters. Therefore, PSBP may be more useful in correcting clinical scans than are other correction techniques previously described

  3. Projection decomposition algorithm for dual-energy computed tomography via deep neural network.

    Science.gov (United States)

    Xu, Yifu; Yan, Bin; Chen, Jian; Zeng, Lei; Li, Lei

    2018-03-15

    Dual-energy computed tomography (DECT) has been widely used to improve identification of substances from different spectral information. Decomposition of the mixed test samples into two materials relies on a well-calibrated material decomposition function. This work aims to establish and validate a data-driven algorithm for estimation of the decomposition function. A deep neural network (DNN) consisting of two sub-nets is proposed to solve the projection decomposition problem. The compressing sub-net, substantially a stack auto-encoder (SAE), learns a compact representation of energy spectrum. The decomposing sub-net with a two-layer structure fits the nonlinear transform between energy projection and basic material thickness. The proposed DNN not only delivers image with lower standard deviation and higher quality in both simulated and real data, and also yields the best performance in cases mixed with photon noise. Moreover, DNN costs only 0.4 s to generate a decomposition solution of 360 × 512 size scale, which is about 200 times faster than the competing algorithms. The DNN model is applicable to the decomposition tasks with different dual energies. Experimental results demonstrated the strong function fitting ability of DNN. Thus, the Deep learning paradigm provides a promising approach to solve the nonlinear problem in DECT.

  4. Effect of number of of projections on inverse radon transform based image reconstruction by using filtered back-projection for parallel beam transmission tomography

    International Nuclear Information System (INIS)

    Qureshi, S.A.; Mirza, S.M.; Arif, M.

    2007-01-01

    This paper present the effect of number of projections on inverse Radon transform (IRT) estimation using filtered back-projection (FBP) technique for parallel beam transmission tomography. The head phantom and the lung phantom have been used in this work. Various filters used in this study include Ram-Lak, Shepp-Logan, Cosin, Hamming and Hanning filters. The slices have been reconstructed by increasing the number of projections through parallel beam transmission tomography keeping the projections uniformly distributed. The Euclidean and Mean Squared errors and peak signal-to-noise ratio (PSNR) have been analyzed for their sensitiveness as functions of number of projections. It has found that image quality improves with the number of projections but at the cost of the computer time. The error has been minimized to get the best approximation of inverse Radon transform (IRT) as the number of projections is enhanced. The value of PSNR has been found to increase from 8.20 to 24.53 dB as the number of projections is raised from 5 to 180 for head phantom. (author)

  5. The Muon Portal Project: Development of an Innovative Scanning Portal Based on Muon Tomography

    International Nuclear Information System (INIS)

    Bonanno, D.-L.; Indelicato, V.; Rocca, P.-La; Leonora, E.; Longhitano, F.; Presti, D.Lo; Petta, C.; Pugliatti, C.; Randazzo, N.; Riggi, F.; Russo, G.V.; Zappala, G.; Santagati, G.; Bonanno, G.; Antonuccio, V.; Bandieramonte, M.; Becciani, U.; Belluso, M.; Billotta, S.; Costa, A.; Massimino, P.; Pistagna, C.; Riggi, S.; Carbone, B.; Fallica, G.; Mazzillo, M.; Piana, A.; Sanfilippo, D.; Valvo, G.; Zaia, A.; Belluomo, F.; Puglisi, M.

    2013-06-01

    The Muon Portal is a recent Project [1] which aims at the construction of a 18 m 2 tracking detector for cosmic muons. This apparatus has been designed as a real-size prototype to inspect containers using the muon tomography technique, i.e. by measuring the deflection of muons when traversing high-Z materials. The detection setup is based on eight position-sensitive X-Y planes, four placed below and four above the volume to be inspected, with good tracking capabilities for charged particles. The detection planes are segmented into strips of extruded plastic scintillators with WLS fibres to transport the light produced in the scintillator material to the photo-sensors (SiPMs) at one of the fibre ends. Detailed GEANT4 simulations have been carried out under different scenarios to investigate the response of the apparatus. The tomographic images are reconstructed by tracking algorithms and suitable imaging software tools. Simulations have demonstrated the possibility to reconstruct a 3D image of the volume to be inspected in a reasonable amount of time, compatible with the requirement of a fast inspection technique. The first two of the 48 detection modules are presently under construction. (authors)

  6. Block matching sparsity regularization-based image reconstruction for incomplete projection data in computed tomography

    Science.gov (United States)

    Cai, Ailong; Li, Lei; Zheng, Zhizhong; Zhang, Hanming; Wang, Linyuan; Hu, Guoen; Yan, Bin

    2018-02-01

    In medical imaging many conventional regularization methods, such as total variation or total generalized variation, impose strong prior assumptions which can only account for very limited classes of images. A more reasonable sparse representation frame for images is still badly needed. Visually understandable images contain meaningful patterns, and combinations or collections of these patterns can be utilized to form some sparse and redundant representations which promise to facilitate image reconstructions. In this work, we propose and study block matching sparsity regularization (BMSR) and devise an optimization program using BMSR for computed tomography (CT) image reconstruction for an incomplete projection set. The program is built as a constrained optimization, minimizing the L1-norm of the coefficients of the image in the transformed domain subject to data observation and positivity of the image itself. To solve the program efficiently, a practical method based on the proximal point algorithm is developed and analyzed. In order to accelerate the convergence rate, a practical strategy for tuning the BMSR parameter is proposed and applied. The experimental results for various settings, including real CT scanning, have verified the proposed reconstruction method showing promising capabilities over conventional regularization.

  7. A new linear back projection algorithm to electrical tomography based on measuring data decomposition

    Science.gov (United States)

    Sun, Benyuan; Yue, Shihong; Cui, Ziqiang; Wang, Huaxiang

    2015-12-01

    As an advanced measurement technique of non-radiant, non-intrusive, rapid response, and low cost, the electrical tomography (ET) technique has developed rapidly in recent decades. The ET imaging algorithm plays an important role in the ET imaging process. Linear back projection (LBP) is the most used ET algorithm due to its advantages of dynamic imaging process, real-time response, and easy realization. But the LBP algorithm is of low spatial resolution due to the natural ‘soft field’ effect and ‘ill-posed solution’ problems; thus its applicable ranges are greatly limited. In this paper, an original data decomposition method is proposed, and every ET measuring data are decomposed into two independent new data based on the positive and negative sensing areas of the measuring data. Consequently, the number of total measuring data is extended to twice as many as the number of the original data, thus effectively reducing the ‘ill-posed solution’. On the other hand, an index to measure the ‘soft field’ effect is proposed. The index shows that the decomposed data can distinguish between different contributions of various units (pixels) for any ET measuring data, and can efficiently reduce the ‘soft field’ effect of the ET imaging process. In light of the data decomposition method, a new linear back projection algorithm is proposed to improve the spatial resolution of the ET image. A series of simulations and experiments are applied to validate the proposed algorithm by the real-time performances and the progress of spatial resolutions.

  8. A new linear back projection algorithm to electrical tomography based on measuring data decomposition

    International Nuclear Information System (INIS)

    Sun, Benyuan; Yue, Shihong; Cui, Ziqiang; Wang, Huaxiang

    2015-01-01

    As an advanced measurement technique of non-radiant, non-intrusive, rapid response, and low cost, the electrical tomography (ET) technique has developed rapidly in recent decades. The ET imaging algorithm plays an important role in the ET imaging process. Linear back projection (LBP) is the most used ET algorithm due to its advantages of dynamic imaging process, real-time response, and easy realization. But the LBP algorithm is of low spatial resolution due to the natural ‘soft field’ effect and ‘ill-posed solution’ problems; thus its applicable ranges are greatly limited. In this paper, an original data decomposition method is proposed, and every ET measuring data are decomposed into two independent new data based on the positive and negative sensing areas of the measuring data. Consequently, the number of total measuring data is extended to twice as many as the number of the original data, thus effectively reducing the ‘ill-posed solution’. On the other hand, an index to measure the ‘soft field’ effect is proposed. The index shows that the decomposed data can distinguish between different contributions of various units (pixels) for any ET measuring data, and can efficiently reduce the ‘soft field’ effect of the ET imaging process. In light of the data decomposition method, a new linear back projection algorithm is proposed to improve the spatial resolution of the ET image. A series of simulations and experiments are applied to validate the proposed algorithm by the real-time performances and the progress of spatial resolutions. (paper)

  9. MIT Project Apophis: Surface Evaulation & Tomography (SET) Mission Study for the April 2029 Earth Encounter

    Science.gov (United States)

    Binzel, R. P.; Earle, A. M.; Vanatta, M.; Miller, D. W.

    2017-12-01

    Nature is providing a once-per-thousand year opportunity to study the geophysical outcome induced on an unprecedentedly large (350 meter) asteroid making an extremely close passage by the Earth (inside the distance of geosynchronous satellites) on Friday April 13, 2029. The aircraft carrier-sized (estimated 20 million metric ton) asteroid is named Apophis. While many previous spacecraft missions have studied asteroids, none has ever had the opportunity to study "live" the outcome of planetary tidal forces on their shapes, spin states, surface geology, and internal structure. Beyond the science interest directly observing this planetary process, the Apophis encounter provides an invaluable opportunity to gain knowledge for any eventuality of a known asteroid found to be on a certain impact trajectory. MIT's Project Apophis [1] is our response to nature's generous opportunity by developing a detailed mission concept for sending a spacecraft to orbit Apophis with the objectives of surveying its surface and interior structure before, during, and after its 2029 near-Earth encounter. The Surface Evaluation & Tomography (SET) mission concept we present is designed toward accomplishing three key science objectives: (1) bulk physical characterization, (2) internal structure, and (3) long-term orbit tracking. For its first mission objective, SET will study Apophis' bulk properties, including: shape, size, mass, volume, bulk density, surface geology, and composition, rotation rate, and spin state. The second mission objective is to characterize Apophis' internal structure before and after the encounter to determine its strength and cohesion - including tidally induced changes. Finally, the third objective studies the process of thermal re-radiation and consequential Yarkovsky drift, whose results will improve orbit predictions for Apophis as well as other potentially hazardous asteroids. [1] https://eapsweb.mit.edu/mit-project-apophis

  10. Standards, Assessments & Opting Out, Spring 2015

    Science.gov (United States)

    Advance Illinois, 2015

    2015-01-01

    In the spring, Illinois students will take new state assessments that reflect the rigor and relevance of the new Illinois Learning Standards. But some classmates will sit out and join the pushback against standardized testing. Opt-out advocates raise concerns about over-testing, and the resulting toll on students as well as the impact on classroom…

  11. A novel forward projection-based metal artifact reduction method for flat-detector computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Prell, Daniel; Kyriakou, Yiannis; Beister, Marcel; Kalender, Willi A [Institute of Medical Physics, University of Erlangen-Nuernberg, Henkestrasse 91, 91052 Erlangen (Germany)], E-mail: daniel.prell@imp.uni-erlangen.de

    2009-11-07

    Metallic implants generate streak-like artifacts in flat-detector computed tomography (FD-CT) reconstructed volumetric images. This study presents a novel method for reducing these disturbing artifacts by inserting discarded information into the original rawdata using a three-step correction procedure and working directly with each detector element. Computation times are minimized by completely implementing the correction process on graphics processing units (GPUs). First, the original volume is corrected using a three-dimensional interpolation scheme in the rawdata domain, followed by a second reconstruction. This metal artifact-reduced volume is then segmented into three materials, i.e. air, soft-tissue and bone, using a threshold-based algorithm. Subsequently, a forward projection of the obtained tissue-class model substitutes the missing or corrupted attenuation values directly for each flat detector element that contains attenuation values corresponding to metal parts, followed by a final reconstruction. Experiments using tissue-equivalent phantoms showed a significant reduction of metal artifacts (deviations of CT values after correction compared to measurements without metallic inserts reduced typically to below 20 HU, differences in image noise to below 5 HU) caused by the implants and no significant resolution losses even in areas close to the inserts. To cover a variety of different cases, cadaver measurements and clinical images in the knee, head and spine region were used to investigate the effectiveness and applicability of our method. A comparison to a three-dimensional interpolation correction showed that the new approach outperformed interpolation schemes. Correction times are minimized, and initial and corrected images are made available at almost the same time (12.7 s for the initial reconstruction, 46.2 s for the final corrected image compared to 114.1 s and 355.1 s on central processing units (CPUs))

  12. A novel forward projection-based metal artifact reduction method for flat-detector computed tomography

    International Nuclear Information System (INIS)

    Prell, Daniel; Kyriakou, Yiannis; Beister, Marcel; Kalender, Willi A

    2009-01-01

    Metallic implants generate streak-like artifacts in flat-detector computed tomography (FD-CT) reconstructed volumetric images. This study presents a novel method for reducing these disturbing artifacts by inserting discarded information into the original rawdata using a three-step correction procedure and working directly with each detector element. Computation times are minimized by completely implementing the correction process on graphics processing units (GPUs). First, the original volume is corrected using a three-dimensional interpolation scheme in the rawdata domain, followed by a second reconstruction. This metal artifact-reduced volume is then segmented into three materials, i.e. air, soft-tissue and bone, using a threshold-based algorithm. Subsequently, a forward projection of the obtained tissue-class model substitutes the missing or corrupted attenuation values directly for each flat detector element that contains attenuation values corresponding to metal parts, followed by a final reconstruction. Experiments using tissue-equivalent phantoms showed a significant reduction of metal artifacts (deviations of CT values after correction compared to measurements without metallic inserts reduced typically to below 20 HU, differences in image noise to below 5 HU) caused by the implants and no significant resolution losses even in areas close to the inserts. To cover a variety of different cases, cadaver measurements and clinical images in the knee, head and spine region were used to investigate the effectiveness and applicability of our method. A comparison to a three-dimensional interpolation correction showed that the new approach outperformed interpolation schemes. Correction times are minimized, and initial and corrected images are made available at almost the same time (12.7 s for the initial reconstruction, 46.2 s for the final corrected image compared to 114.1 s and 355.1 s on central processing units (CPUs)).

  13. 12 CFR 334.27 - Renewal of opt-out.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Renewal of opt-out. 334.27 Section 334.27 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION REGULATIONS AND STATEMENTS OF GENERAL POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.27 Renewal of opt-out. (a) Renewal notice and opt-out...

  14. 17 CFR 248.124 - Reasonable opportunity to opt out.

    Science.gov (United States)

    2010-04-01

    ...” to indicate their opt out preference or that requires the consumer to check one of two blank check... affiliate to make marketing solicitations to a consumer about your products or services unless the consumer... a reasonable opportunity to opt out. The consumer is given a reasonable opportunity to opt out if...

  15. 75 FR 51266 - Reedsport OPT Wave Park, LLC; Notice of Settlement Agreement and Soliciting Comments

    Science.gov (United States)

    2010-08-19

    ... of Practice and Procedure, 18 CFR 385.602, Federal Power Act 16 U.S.C. 791 (a)-825(r). h. Applicant... behalf of itself; National Marine Fisheries Service; U.S. Fish and Wildlife Service; U.S. Forest Service... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 12713-002] Reedsport OPT...

  16. Basic methodology of tomographic imaging by filtered inverse projection at a turbo-pump. Project report; Methodische Grundlagen fuer die Tomographie durch gefilterte Rueckprojektion an einer Axialpumpe. Projektbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, D.

    2000-11-01

    A two-phase medium consisting of a fluid containing gas is transported in a turbo-pump via an impeller. The interaction between the gaseous phase and the impeller is to be examined by tomography with gamma rays. Reconstruction of the image of the object is to be made by way of filtered inverse projection. The methodology of using this principle in the given system (geometry and measuring conditions) is explained. (orig./CB) [German] Ein zweiphasiges, aus einer gashaltigen Fluessigkeit bestehendes Medium wird in einer Axialpumpe von einem propellerartigen Laufrad senkrecht zur Drehachse dieses Laufrades transportiert. Die Wechselwirkung zwischen der Gasphase und dem Laufrad soll unter Verwendung von Gamma-Strahlung mittels Tomographie untersucht werden. Dabei ist fuer die Rekonstruktion des Objektbildes das Prinzip der sogenannten gefilterten Rueckprojektion vorgesehen. Die methodischen Grundlagen fuer die Nutzung dieses Prinzips unter von vorgesehenen geometrischen und messtechnischen Bedingungen sind Gegenstand dieser Arbeit. (orig.)

  17. Opting in and opting out: a grounded theory of nursing's contribution to inpatient rehabilitation.

    Science.gov (United States)

    Pryor, Julie; Walker, Annette; O'Connell, Beverly; Worrall-Carter, Linda

    2009-12-01

    To develop a grounded theory of nursing's contribution to patient rehabilitation from the perspective of nurses working in inpatient rehabilitation. Grounded theory method, informed by the theoretical perspective of symbolic interactionism, was used to guide data collection and analysis, and the development of a grounded theory. Five inpatient rehabilitation units in Australia. Thirty-five registered and 18 enrolled nurses participated in audio-taped interviews and/or were observed during periods of their everyday practice. The analysis revealed a situation whereby nurses made decisions about when to 'opt in' and when to 'opt out' of inpatient rehabilitation. This occurred on two levels: with their interaction with patients and allied health professionals, and when faced with negative system issues that impacted on their ability to contribute to patient rehabilitation. The primary contribution nurses made to inpatient rehabilitation was working directly with patients, enabling them to self-care. Nurses coached patients when their decisions about 'opting in' and 'opting out' were based on assessment of the person in their particular context. In contrast, the nurses mostly distanced themselves from system-based problems, 'opting out' of addressing them. They did this not to make their working lives easier, but more manageable. System-based problems impacted negatively on the nurses' ability to deliver comprehensive rehabilitation care. As a consequence, some nurses felt unable to influence the care and they withdrew professionally to make their work lives more manageable.

  18. TH-E-17A-05: Optimizing Four Dimensional Cone Beam Computed Tomography Projection Allocation to Respiratory Bins

    International Nuclear Information System (INIS)

    OBrien, R; Shieh, C; Kipritidis, J; Keall, P

    2014-01-01

    Purpose: Four dimensional cone beam computed tomography (4DCBCT) is an emerging image guidance strategy but it can suffer from poor image quality. To avoid repeating scans it is beneficial to make the best use of the imaging data obtained. For conventional 4DCBCT the location and size of respiratory bins is fixed and projections are allocated to the respiratory bin within which it falls. Strictly adhering to this rule is unnecessary and can compromise image quality. In this study we optimize the size and location of respiratory bins and allow projections to be sourced from adjacent phases of the respiratory cycle. Methods: A mathematical optimization framework using mixed integer quadratic programming has been developed that determines when to source projections from adjacent respiratory bins and optimizes the size and location of the bins. The method, which we will call projection sharing, runs in under 2 seconds of CPU time. Five 4DCBCT datasets of stage III-IV lung cancer patients were used to test the algorithm. The standard deviation of the angular separation between projections (SD-A) and the standard deviation in the volume of the reconstructed fiducial gold coil (SD-V) were used as proxies to measure streaking artefacts and motion blur respectively. Results: The SD-A using displacement binning and projection sharing was 30%–50% smaller than conventional phase based binning and 59%–76% smaller than conventional displacement binning indicating more uniformly spaced projections and fewer streaking artefacts. The SD-V was 20–90% smaller when using projection sharing than using conventional phase based binning suggesting more uniform marker segmentation and less motion blur. Conclusion: Image quality was visibly and significantly improved with projection sharing. Projection sharing does not require any modifications to existing hardware and offers a more robust replacement to phase based binning, or, an option if phase based reconstruction is not of a

  19. Improving image quality in Electrical Impedance Tomography (EIT using Projection Error Propagation-based Regularization (PEPR technique: A simulation study

    Directory of Open Access Journals (Sweden)

    Tushar Kanti Bera

    2011-03-01

    Full Text Available A Projection Error Propagation-based Regularization (PEPR method is proposed and the reconstructed image quality is improved in Electrical Impedance Tomography (EIT. A projection error is produced due to the misfit of the calculated and measured data in the reconstruction process. The variation of the projection error is integrated with response matrix in each iterations and the reconstruction is carried out in EIDORS. The PEPR method is studied with the simulated boundary data for different inhomogeneity geometries. Simulated results demonstrate that the PEPR technique improves image reconstruction precision in EIDORS and hence it can be successfully implemented to increase the reconstruction accuracy in EIT.>doi:10.5617/jeb.158 J Electr Bioimp, vol. 2, pp. 2-12, 2011

  20. Automated patient setup and gating using cone beam computed tomography projections

    DEFF Research Database (Denmark)

    Wan, Hanlin; Bertholet, Jenny; Ge, Jiajia

    2016-01-01

    In radiation therapy, fiducial markers are often implanted near tumors and used for patient positioning and respiratory gating purposes. These markers are then used to manually align the patients by matching the markers in the cone beam computed tomography (CBCT) reconstruction to those...

  1. CTmod—A toolkit for Monte Carlo simulation of projections including scatter in computed tomography

    Czech Academy of Sciences Publication Activity Database

    Malušek, Alexandr; Sandborg, M.; Alm Carlsson, G.

    2008-01-01

    Roč. 90, č. 2 (2008), s. 167-178 ISSN 0169-2607 Institutional research plan: CEZ:AV0Z10480505 Keywords : Monte Carlo * computed tomography * cone beam * scatter Subject RIV: JC - Computer Hardware ; Software Impact factor: 1.220, year: 2008 http://dx.doi.org/10.1016/j.cmpb.2007.12.005

  2. TVR-DART: A More Robust Algorithm for Discrete Tomography From Limited Projection Data With Automated Gray Value Estimation.

    Science.gov (United States)

    Xiaodong Zhuge; Palenstijn, Willem Jan; Batenburg, Kees Joost

    2016-01-01

    In this paper, we present a novel iterative reconstruction algorithm for discrete tomography (DT) named total variation regularized discrete algebraic reconstruction technique (TVR-DART) with automated gray value estimation. This algorithm is more robust and automated than the original DART algorithm, and is aimed at imaging of objects consisting of only a few different material compositions, each corresponding to a different gray value in the reconstruction. By exploiting two types of prior knowledge of the scanned object simultaneously, TVR-DART solves the discrete reconstruction problem within an optimization framework inspired by compressive sensing to steer the current reconstruction toward a solution with the specified number of discrete gray values. The gray values and the thresholds are estimated as the reconstruction improves through iterations. Extensive experiments from simulated data, experimental μCT, and electron tomography data sets show that TVR-DART is capable of providing more accurate reconstruction than existing algorithms under noisy conditions from a small number of projection images and/or from a small angular range. Furthermore, the new algorithm requires less effort on parameter tuning compared with the original DART algorithm. With TVR-DART, we aim to provide the tomography society with an easy-to-use and robust algorithm for DT.

  3. optBINS: Optimal Binning for histograms

    Science.gov (United States)

    Knuth, Kevin H.

    2018-03-01

    optBINS (optimal binning) determines the optimal number of bins in a uniform bin-width histogram by deriving the posterior probability for the number of bins in a piecewise-constant density model after assigning a multinomial likelihood and a non-informative prior. The maximum of the posterior probability occurs at a point where the prior probability and the the joint likelihood are balanced. The interplay between these opposing factors effectively implements Occam's razor by selecting the most simple model that best describes the data.

  4. Images of gravitational and magnetic phenomena derived from two-dimensional back-projection Doppler tomography of interacting binary stars

    International Nuclear Information System (INIS)

    Richards, Mercedes T.; Cocking, Alexander S.; Fisher, John G.; Conover, Marshall J.

    2014-01-01

    We have used two-dimensional back-projection Doppler tomography as a tool to examine the influence of gravitational and magnetic phenomena in interacting binaries that undergo mass transfer from a magnetically active star onto a non-magnetic main-sequence star. This multitiered study of over 1300 time-resolved spectra of 13 Algol binaries involved calculations of the predicted dynamical behavior of the gravitational flow and the dynamics at the impact site, analysis of the velocity images constructed from tomography, and the influence on the tomograms of orbital inclination, systemic velocity, orbital coverage, and shadowing. The Hα tomograms revealed eight sources: chromospheric emission, a gas stream along the gravitational trajectory, a star-stream impact region, a bulge of absorption or emission around the mass-gaining star, a Keplerian accretion disk, an absorption zone associated with hotter gas, a disk-stream impact region, and a hot spot where the stream strikes the edge of a disk. We described several methods used to extract the physical properties of the emission sources directly from the velocity images, including S-wave analysis, the creation of simulated velocity tomograms from hydrodynamic simulations, and the use of synthetic spectra with tomography to sequentially extract the separate sources of emission from the velocity image. In summary, the tomography images have revealed results that cannot be explained solely by gravitational effects: chromospheric emission moving with the mass-losing star, a gas stream deflected from the gravitational trajectory, and alternating behavior between stream state and disk state. Our results demonstrate that magnetic effects cannot be ignored in these interacting binaries.

  5. Lower Extremity Revascularization Using Optical Coherence Tomography-Guided Directional Atherectomy: Final Results of the EValuatIon of the PantheriS OptIcal COherence Tomography ImagiNg Atherectomy System for Use in the Peripheral Vasculature (VISION) Study.

    Science.gov (United States)

    Schwindt, Arne G; Bennett, J Gray; Crowder, William H; Dohad, Suhail; Janzer, Sean F; George, Jon C; Tedder, Barry; Davis, Thomas P; Cawich, Ian M; Gammon, Roger S; Muck, Patrick E; Pigott, John P; Dishmon, Dwight A; Lopez, Lou A; Golzar, Jaafer A; Chamberlin, Jack R; Moulton, Michael J; Zakir, Ramzan M; Kaki, Amir K; Fishbein, Gary J; McDaniel, Huey B; Hezi-Yamit, Ayala; Simpson, John B; Desai, Arjun

    2017-06-01

    To evaluate the safety and efficacy of a novel optical coherence tomography (OCT)-guided atherectomy catheter in treating patients with symptomatic femoropopliteal disease. The VISION trial ( ClinicalTrials.gov identifier NCT01937351) was a single-arm, multicenter, global investigational device exemption study enrolling 158 subjects (mean age 67.2±10.5 years; 87 men) across 20 participating sites. In this cohort, 198 lesions were treated with an average length of 53±40 mm using the Pantheris catheter alone or Pantheris + adjunctive therapy. The primary safety endpoint was the composite of major adverse events (MAEs) through 6 months (objective performance goal 43.2%). Technical success (primary efficacy outcome) was defined as the percent of target lesions with a residual diameter stenosis ≤50% after treatment with the Pantheris device alone (objective performance goal 87.0%). Procedural success was defined as reduction in stenosis to ≤30% after Pantheris ± adjunctive therapy. Tissue specimens retrieved from each treated lesion were histologically analyzed to evaluate the accuracy and precision of OCT image guidance. The primary efficacy outcome was achieved in 192 (97.0%) of the 198 lesions treated with the Pantheris catheter. Across all lesions, mean diameter stenosis was reduced from 78.7%±15.1% at baseline to 30.3%±11.8% after Pantheris alone (patherectomy specimens confirmed atherectomy for femoropopliteal disease is safe and effective. Additionally, the precision afforded by OCT guidance leads to greater removal of plaque during atherectomy while sparing the adventitia.

  6. 17 CFR 160.7 - Form of opt out notice to consumers; opt out methods.

    Science.gov (United States)

    2010-04-01

    ... consumer agrees, electronically. (2) When a customer relationship terminates, the customer's opt out... that relationship. If the individual subsequently establishes a new customer relationship with you, the... relationships. (1) If two or more consumers jointly obtain a financial product or service from you, you may...

  7. MULTILEVEL ISCHEMIA IN DISORGANIZATION OF THE RETINAL INNER LAYERS ON PROJECTION-RESOLVED OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

    Science.gov (United States)

    Onishi, Alex C; Ashraf, Mohammed; Soetikno, Brian T; Fawzi, Amani A

    2018-04-10

    To examine the relationship between ischemia and disorganization of the retinal inner layers (DRIL). Cross-sectional retrospective study of 20 patients (22 eyes) with diabetic retinopathy presenting to a tertiary academic referral center, who had DRIL on structural optical coherence tomography (OCT) using Spectralis HRA + OCT (Heidelberg Engineering, Heidelberg, Germany) and OCT angiography with XR Avanti (Optovue Inc, Fremont, CA) on the same day. Optical coherence tomography angiography images were further processed to remove flow signal projection artifacts using a software algorithm adapted from recent studies. Retinal capillary perfusion in the superficial capillary plexuses, middle capillary plexuses, and deep capillary plexuses, as well as integrity of the photoreceptor lines on OCT was compared in areas with DRIL to control areas without DRIL in the same eye. Qualitative assessment of projection-resolved OCT angiography of eyes with DRIL on structural OCT demonstrated significant perfusion deficits compared with adjacent control areas (P < 0.001). Most lesions (85.7%) showed superimposed superficial capillary plexus and/or middle capillary plexus nonperfusion in addition to deep capillary plexus nonflow. Areas of DRIL were significantly associated with photoreceptor disruption (P = 0.035) compared with adjacent DRIL-free areas. We found that DRIL is associated with multilevel retinal capillary nonperfusion, suggesting an important role for ischemia in this OCT phenotype.

  8. Tomography of images with poisson miose: pre-processing of projections

    International Nuclear Information System (INIS)

    Furuie, S.S.

    1989-01-01

    This work present an alternative approach in order to reconstruct images with low signal to noise ratio. Basically it consist of smoothing projections taking into account that the noise is Poisson. These filtered projections are used to reconstruct the original image, applying direct Fourier method. This approach is compared with convolution back projection and EM (Expectation-Maximization). (author) [pt

  9. Geometrical differences in target volumes based on 18F-fluorodeoxyglucose positron emission tomography/computed tomography and four-dimensional computed tomography maximum intensity projection images of primary thoracic esophageal cancer.

    Science.gov (United States)

    Guo, Y; Li, J; Wang, W; Zhang, Y; Wang, J; Duan, Y; Shang, D; Fu, Z

    2014-01-01

    The objective of the study was to compare geometrical differences of target volumes based on four-dimensional computed tomography (4DCT) maximum intensity projection (MIP) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) images of primary thoracic esophageal cancer for radiation treatment. Twenty-one patients with thoracic esophageal cancer sequentially underwent contrast-enhanced three-dimensional computed tomography (3DCT), 4DCT, and 18F-FDG PET/CT thoracic simulation scans during normal free breathing. The internal gross target volume defined as IGTVMIP was obtained by contouring on MIP images. The gross target volumes based on PET/CT images (GTVPET ) were determined with nine different standardized uptake value (SUV) thresholds and manual contouring: SUV≥2.0, 2.5, 3.0, 3.5 (SUVn); ≥20%, 25%, 30%, 35%, 40% of the maximum (percentages of SUVmax, SUVn%). The differences in volume ratio (VR), conformity index (CI), and degree of inclusion (DI) between IGTVMIP and GTVPET were investigated. The mean centroid distance between GTVPET and IGTVMIP ranged from 4.98 mm to 6.53 mm. The VR ranged from 0.37 to 1.34, being significantly (P<0.05) closest to 1 at SUV2.5 (0.94), SUV20% (1.07), or manual contouring (1.10). The mean CI ranged from 0.34 to 0.58, being significantly closest to 1 (P<0.05) at SUV2.0 (0.55), SUV2.5 (0.56), SUV20% (0.56), SUV25% (0.53), or manual contouring (0.58). The mean DI of GTVPET in IGTVMIP ranged from 0.61 to 0.91, and the mean DI of IGTVMIP in GTVPET ranged from 0.34 to 0.86. The SUV threshold setting of SUV2.5, SUV20% or manual contouring yields the best tumor VR and CI with internal-gross target volume contoured on MIP of 4DCT dataset, but 3DPET/CT and 4DCT MIP could not replace each other for motion encompassing target volume delineation for radiation treatment. © 2014 International Society for Diseases of the Esophagus.

  10. Opting out of an ever closer union

    DEFF Research Database (Denmark)

    Adler-Nissen, Rebecca

    2011-01-01

    How is sovereignty managed in the EU? This paper investigates the relationship between sovereignty and European integration through the prism of national opt-outs from EU treaties, addressing an apparent contradiction in contemporary European governance: the contrasting processes of integration...... and differentiation. On the one hand, European integration is increasing as states transfer sovereign competencies to the EU. On the other hand, we see a multitude of differentiation processes through which member states choose to disengage from the EU polity by negotiating exemptions or derogations. Drawing...... on Pierre Bourdieu’s political sociology, the paper argues that to understand how sovereignty is exercised and interpreted in the EU, it is necessary to focus not only on the constitutive and regulative dimensions of sovereignty, but equally on the practice dimension. This entails an exploration of how...

  11. Optimizing 4D cone beam computed tomography acquisition by varying the gantry velocity and projection time interval

    International Nuclear Information System (INIS)

    O’Brien, Ricky T; Cooper, Benjamin J; Keall, Paul J

    2013-01-01

    Four dimensional cone beam computed tomography (4DCBCT) is an emerging clinical image guidance strategy for tumour sites affected by respiratory motion. In current generation 4DCBCT techniques, both the gantry rotation speed and imaging frequency are constant and independent of the patient’s breathing which can lead to projection clustering. We present a mixed integer quadratic programming (MIQP) model for respiratory motion guided-4DCBCT (RMG-4DCBCT) which regulates the gantry velocity and projection time interval, in response to the patient’s respiratory signal, so that a full set of evenly spaced projections can be taken in a number of phase, or displacement, bins during the respiratory cycle. In each respiratory bin, an image can be reconstructed from the projections to give a 4D view of the patient’s anatomy so that the motion of the lungs, and tumour, can be observed during the breathing cycle. A solution to the full MIQP model in a practical amount of time, 10 s, is not possible with the leading commercial MIQP solvers, so a heuristic method is presented. Using parameter settings typically used on current generation 4DCBCT systems (4 min image acquisition, 1200 projections, 10 respiratory bins) and a sinusoidal breathing trace with a 4 s period, we show that the root mean square (RMS) of the angular separation between projections with displacement binning is 2.7° using existing constant gantry speed systems and 0.6° using RMG-4DCBCT. For phase based binning the RMS is 2.7° using constant gantry speed systems and 2.5° using RMG-4DCBCT. The optimization algorithm presented is a critical step on the path to developing a system for RMG-4DCBCT. (paper)

  12. Comparison of tomography reconstruction by maximum entropy and filtered retro projection

    International Nuclear Information System (INIS)

    Abdala, F.J.P.; Simpson, D.M.; Roberty, N.C.

    1992-01-01

    The tomographic reconstruction with few projections is studied, comparing the maximum entropy method with filtered retro projection. Simulations with and without the presence of noise and also with the presence of an object of high density inside of the skull are showed. (C.G.C.)

  13. 12 CFR 222.27 - Renewal of opt-out.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Renewal of opt-out. 222.27 Section 222.27 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.27 Renewal of opt-out. (a) Renewal notice and...

  14. 12 CFR 717.27 - Renewal of opt-out.

    Science.gov (United States)

    2010-01-01

    ... applies. (2) Renewal period. Each opt-out renewal must be effective for a period of at least five years as... companies, or their successors, that jointly provided the previous opt-out notice. (b) Contents of renewal... provided by multiple companies with the ABC name or multiple companies in the ABC group or family of...

  15. 12 CFR 222.24 - Reasonable opportunity to opt out.

    Science.gov (United States)

    2010-01-01

    ... consumers to write a “yes” or “no” to indicate their opt-out preference or that requires the consumer to... opt out. (a) In general. You must not use eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the...

  16. 12 CFR 571.24 - Reasonable opportunity to opt out.

    Science.gov (United States)

    2010-01-01

    ... completing a form that requires consumers to write a “yes” or “no” to indicate their opt-out preference or... eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the consumer is provided a reasonable opportunity to opt...

  17. Private International Law Issues in Opt-out and Opt-in Instruments of Harmonization

    DEFF Research Database (Denmark)

    Fogt, Morten Midtgaard

    2013-01-01

    of Goods from 1980 (CISG) and the European Commission Proposal for a common European Sales Law from 2011 (CESL). Although the two instruments of substantial harmonization regulate the same area of civil law, they differ with respect to the type of formal instrument of harmonization, the material, personal......This article deals with opt-in and opt-out instruments of harmonization, how they apply and compete. It analyses the Private International Law (PIL) issues which arise and bases the analysis on the two instruments of harmonization – the Vienna Convention on Contract for the International Sale...... into these questions and argues, inter alia, that the CISG as a global international convention should have priority over the regional CESL, that the choice of the CESL should be based on a PIL choice of binding European ‘Community rules of law’, that both instruments cannot possible overrule the established PIL...

  18. Comparison of two chemically-induced colitis-models in adult zebrafish, using optical projection tomography and novel transcriptional markers

    DEFF Research Database (Denmark)

    Haarder, Simon; Kania, Per Walter; Holm, Thomas

    2016-01-01

    , induced by the haptenizing agents oxazolone and TNBS. In addition, goblet cell dynamics in the scales and intestine and 5-HT (serotonin) in intestinal tissues were investigated through optical projection tomography. Gene expression studies revealed a distinct and significant upregulation...... of proinflammatory cytokines, acute-phase reactants and metalloprotease 9 in both chemical models, primarily after 72 hours. In comparison, transcription factors and cytokines associated with Th1 and Th17 (Crohn’s) and Th2 (ulcerative colitis) were mainly not affected in this acute setting. However, elevated...... transcript levels were detected in Foxp3, IL-10 and T-bet, which are linked with tolerance and Tregs in mammals. Goblet cells in scales were depleted in both chemical models and in the intestine of oxazolone-treated fish. A marked 5-HT signal was noted in intestinal tissue of some chemically treated...

  19. Deflection tomography of a complex flow field based on the visualization of projection array

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Bin; Miao Zhanli, E-mail: zb-sh@163.com [College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266061 (China)

    2011-02-01

    Tomographic techniques are used for the investigation of complex flow fields by means of deflectometric methods. A new deflection tomographic setup for obtaining an array of multidirectional deflectograms is presented. Deflection projections in different angles of view can be captured synchronously in same optical path condition and arranged on the camera in two rows with three views in each row. Tikhonov regularization method is used to reconstruct temperature distribution from deflectometric projection data. The conjugate gradient method is used to compute the regularized solution for the least-square equations. The asymmetric flame temperature distribution in the horizontal section was reconstructed from limited view angle projections. The experimental results of reconstruction from real projection data were satisfactory when compared with the direct thermocouple measurements.

  20. Optimizing experimental parameters for the projection requirement in HAADF-STEM tomography

    Energy Technology Data Exchange (ETDEWEB)

    Aveyard, R., E-mail: r.a.aveyard@tudelft.nl [Department of Imaging Physics, Delft University of Technology, 2628CJ Delft (Netherlands); Zhong, Z.; Batenburg, K.J. [Centrum Wiskunde and Informatica, Science Park 123, NL-1098 XG Amsterdam (Netherlands); Rieger, B., E-mail: b.rieger@tudelft.nl [Department of Imaging Physics, Delft University of Technology, 2628CJ Delft (Netherlands)

    2017-06-15

    Highlights: • The extent to which HAADF-STEM meets the projection requirement has been studied. • Multislice simulations used to model beam propagation and study signal linearity. • Propagation in crystalline and amorphous materials considered. • Optimal experimental set-up for the projection requirement is discussed. - Abstract: Tomographic reconstruction algorithms offer a means by which a tilt-series of transmission images can be combined to yield a three dimensional model of the specimen. Conventional reconstruction algorithms assume that the measured signal is a linear projection of some property, typically the density, of the material. Here we report the use of multislice simulations to investigate the extent to which this assumption is met in HAADF-STEM imaging. The use of simulations allows for a systematic survey of a range of materials and microscope parameters to inform optimal experimental design. Using this approach it is demonstrated that the imaging of amorphous materials is in good agreement with the projection assumption in most cases. Images of crystalline specimens taken along zone-axes are found to be poorly suited for conventional linear reconstruction algorithms due to channelling effects which produce enhanced intensities compared with off-axis images, and poor compliance with the projection requirement. Off-axis images are found to be suitable for reconstruction, though they do not strictly meet the linearity requirement in most cases. It is demonstrated that microscope parameters can be selected to yield improved compliance with the projection requirement.

  1. Optimizing experimental parameters for the projection requirement in HAADF-STEM tomography

    International Nuclear Information System (INIS)

    Aveyard, R.; Zhong, Z.; Batenburg, K.J.; Rieger, B.

    2017-01-01

    Highlights: • The extent to which HAADF-STEM meets the projection requirement has been studied. • Multislice simulations used to model beam propagation and study signal linearity. • Propagation in crystalline and amorphous materials considered. • Optimal experimental set-up for the projection requirement is discussed. - Abstract: Tomographic reconstruction algorithms offer a means by which a tilt-series of transmission images can be combined to yield a three dimensional model of the specimen. Conventional reconstruction algorithms assume that the measured signal is a linear projection of some property, typically the density, of the material. Here we report the use of multislice simulations to investigate the extent to which this assumption is met in HAADF-STEM imaging. The use of simulations allows for a systematic survey of a range of materials and microscope parameters to inform optimal experimental design. Using this approach it is demonstrated that the imaging of amorphous materials is in good agreement with the projection assumption in most cases. Images of crystalline specimens taken along zone-axes are found to be poorly suited for conventional linear reconstruction algorithms due to channelling effects which produce enhanced intensities compared with off-axis images, and poor compliance with the projection requirement. Off-axis images are found to be suitable for reconstruction, though they do not strictly meet the linearity requirement in most cases. It is demonstrated that microscope parameters can be selected to yield improved compliance with the projection requirement.

  2. Direct image reconstruction with limited angle projection data for computerized tomography

    International Nuclear Information System (INIS)

    Inouye, T.

    1980-01-01

    Discussions are made on the minimum angle range for projection data necessary to reconstruct the complete CT image. As is easily shown from the image reconstruction theorem, the lack of projection angle provides no data for the Fourier transformed function of the object on the corresponding angular directions, where the projections are missing. In a normal situation, the Fourier transformed function of an object image holds an analytic characteristic with respect to two-dimensional orthogonal parameters. This characteristic enables uniquely prolonging the function outside the obtained region employing a sort of analytic continuation with respect to both parameters. In the method reported here, an object pattern, which is confined within a finite range, is shifted to a specified region to have complete orthogonal function expansions without changing the projection angle directions. These orthogonal functions are analytically extended to the missing projection angle range and the whole function is determined. This method does not include any estimation process, whose effectiveness is often seriously jeopardized by the presence of a slight fluctuation component. Computer simulations were carried out to demonstrate the effectiveness of the method

  3. Prediction of optimal deployment projection for transcatheter aortic valve replacement: angiographic 3-dimensional reconstruction of the aortic root versus multidetector computed tomography.

    OpenAIRE

    Binder Ronald K; Leipsic Jonathon; Wood David; Moore Teri; Toggweiler Stefan; Willson Alex; Gurvitch Ronen; Freeman Melanie; Webb John G

    2012-01-01

    BACKGROUND Identifying the optimal fluoroscopic projection of the aortic valve is important for successful transcatheter aortic valve replacement (TAVR). Various imaging modalities including multidetector computed tomography (MDCT) have been proposed for prediction of the optimal deployment projection. We evaluated a method that provides 3 dimensional angiographic reconstructions (3DA) of the aortic root for prediction of the optimal deployment angle and compared it with MDCT. METHODS AND RES...

  4. Nuclear energy: the cost of opting-out

    International Nuclear Information System (INIS)

    Mueller, U.

    2003-01-01

    This article discusses the results of a study made on the financial and ecological costs that would be incurred if Switzerland opted out of the use of nuclear energy. Figures are quoted for the costs if two Swiss popular initiatives on the subject of opting out of nuclear energy were accepted in voting. The disadvantages offered by the alternatives such as combined gas and steam-turbine power plant, photovoltaics and wind power are quoted. Possible negative effects of opting out on the Swiss economy are looked at and the political aspects of renewing operational permits for nuclear power stations are discussed

  5. Traveltime and waveform tomography analysis of synthetic borehole seismic data based on the CO2SINK project site, Germany

    Science.gov (United States)

    Yang, Can; Fan, Wenfang; Juhlin, Christopher

    2010-05-01

    Time lapse analysis of seismic data is very important for CO2 storage projects. Therefore, we have tested traveltime and waveform tomography methods to detect velocity changes in a CO2 injection reservoir using synthetic time lapse data. The structural model tested is based on the CO2SINK injection site at Ketzin, Germany where CO2 is being injected at about 630-650 m into a saline aquifer. First, we created synthetic time lapse moving source profiling (MSP) data, also known as walkaway profiling. The velocity model used for modeling was based on well logging and lithological information in the injection borehole. Gassmann fluid substitution was used to calculate the reservoir velocity after injection. In this substitution, we assumed a saturation of CO2 of 30%. The model velocity of the reservoir changed from 2750 m/s (before injection) to 2150 m/s (after injection). A 2D finite difference code available in Seismic Unix (www.cwp.mines.edu) was used. 60 source points were distributed along a surface line. The distance from the injection well was between 150m and 858m, with an interval of 12m. We recorded 21 channels at receiver depths from 470m to 670m, with an interval of 10m. The injection layer was assumed to be between 629m and 650m depth. The wavelet used for the synthetic data was a Gaussian derivative with an average frequency of 60Hz. Then first arrivals were picked on both data sets and used as input data for traveltime tomography. For traveltime tomography, the PS_tomo program was used. Since no data were recorded above 470m, the initial velocity model used above this depth was the true velocity model. Below 470m, the initial velocity model increases linearly from 3000m/s to 3250m/s. After inversion, the reservoir velocity and an anhydrite layer (high velocity layer) can be seen clearly in the final inverted velocity models. Using these velocity models as starting models, we performed waveform tomography in the frequency domain using a program supplied by

  6. [Restoration filtering based on projection power spectrum for single-photon emission computed tomography].

    Science.gov (United States)

    Kubo, N

    1995-04-01

    To improve the quality of single-photon emission computed tomographic (SPECT) images, a restoration filter has been developed. This filter was designed according to practical "least squares filter" theory. It is necessary to know the object power spectrum and the noise power spectrum. The power spectrum is estimated from the power spectrum of a projection, when the high-frequency power spectrum of a projection is adequately approximated as a polynomial exponential expression. A study of the restoration with the filter based on a projection power spectrum was conducted, and compared with that of the "Butterworth" filtering method (cut-off frequency of 0.15 cycles/pixel), and "Wiener" filtering (signal-to-noise power spectrum ratio was a constant). Normalized mean-squared errors (NMSE) of the phantom, two line sources located in a 99mTc filled cylinder, were used. NMSE of the "Butterworth" filter, "Wiener" filter, and filtering based on a power spectrum were 0.77, 0.83, and 0.76 respectively. Clinically, brain SPECT images utilizing this new restoration filter improved the contrast. Thus, this filter may be useful in diagnosis of SPECT images.

  7. Restoration filtering based on projection power spectrum for single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Kubo, Naoki

    1995-01-01

    To improve the quality of single-photon emission computed tomographic (SPECT) images, a restoration filter has been developed. This filter was designed according to practical 'least squares filter' theory. It is necessary to know the object power spectrum and the noise power spectrum. The power spectrum is estimated from the power spectrum of a projection, when the high-frequency power spectrum of a projection is adequately approximated as a polynomial exponential expression. A study of the restoration with the filter based on a projection power spectrum was conducted, and compared with that of the 'Butterworth' filtering method (cut-off frequency of 0.15 cycles/pixel), and 'Wiener' filtering (signal-to-noise power spectrum ratio was a constant). Normalized mean-squared errors (NMSE) of the phantom, two line sources located in a 99m Tc filled cylinder, were used. NMSE of the 'Butterworth' filter, 'Wiener' filter, and filtering based on a power spectrum were 0.77, 0.83, and 0.76 respectively. Clinically, brain SPECT images utilizing this new restoration filter improved the contrast. Thus, this filter may be useful in diagnosis of SPECT images. (author)

  8. The Muon Portal Project: A large-area tracking detector for muon tomography

    Science.gov (United States)

    Riggi, F.

    2016-05-01

    The Muon Portal Project [1] is a joint initiative between research and industrial partners, aimed at the construction of a real size detector protoype to search for hidden high-Z fissile materials inside containers by the muon scattering technique. The detector is based on a set of 48 detection modules (1 m × 3 m), so as to provide four X-Y detection planes, two placed above and two below the container to be inspected. After a research and development phase, which led to the choice and test of the individual components, the construction of the full size detector has already started and will be completed in a few months.

  9. Dose comparison of different scan projections of Implagraphy cone beam computed tomography for dental maxillofacial use

    International Nuclear Information System (INIS)

    Fang Dong; Yuan Xianshun; Zhang Dongsheng

    2012-01-01

    Objective: To evaluate the subject's absorbed dose,equivalent dose and effective dose. Methods: The CBCT unit was Implagraphy and three scan projections were selected such as mandible, maxilla and temporomandibular joint (TMJ). Thermoluminescent dosimeter tubes were used to record the absorbed dose at special positions in the head and neck region of an adult skull and tissue-equivalent phantom. 16 interested organs included pituitary, lens, parotid glands, submandibular glands, sublingual glands, diploe, spongy bone of the chin and cervical vertebra, skins of cheeks and nuchal region, thyroid and esophagus. The absorbed dose was measured in these organs, and then the effective dose (E 1990 , E 2007 ) were calculated according to different ICRP tissue weighting factors. Results: The absorbed dose of mandible,maxilla and TMJ scan varied from (0.99 ±0.09) to (12.85 ±0.09)mGy, (0.93 ±0.01) to (13.07 ±0.02) mGy and (0.68 ±0.01) to (10.18 ± 0.04)mGy. There was significant difference among the three scan projections (F=19.61-30992.27, P<0.05). The equivalent doses of lens and skin were (1.11± 0.07)-(5.76 ± 0.06) mSv and (6.96 ± 0.06)-(10.64 ± 0.07) mSv. There was significant difference among the three scan projections (F=4473.02, 9385.50, P<0.05). The effective dose (E 1990 , E 2007 ) was [(191.35±1.53), (325.17 ±2.58) μSv] for mandible scan, [(106.62 ±2.17), (226.28 ±2.81) μSv] for maxilla scan, [(104.21 ± 1.02), (142.36 ± 1.90) μSv]for TMJ scan, respectively. Conclusions: The valid measurement should be taken to reduce the subject's dose such as a careful history and clinical examination before the performance of CBCT, the latest risk/benefit assessment,precise scan position, the shielding of thyroid as well as brain and the smaller volume size as well. (authors)

  10. Clustering analysis for muon tomography data elaboration in the Muon Portal project

    Science.gov (United States)

    Bandieramonte, M.; Antonuccio-Delogu, V.; Becciani, U.; Costa, A.; La Rocca, P.; Massimino, P.; Petta, C.; Pistagna, C.; Riggi, F.; Riggi, S.; Sciacca, E.; Vitello, F.

    2015-05-01

    Clustering analysis is one of multivariate data analysis techniques which allows to gather statistical data units into groups, in order to minimize the logical distance within each group and to maximize the one between different groups. In these proceedings, the authors present a novel approach to the muontomography data analysis based on clustering algorithms. As a case study we present the Muon Portal project that aims to build and operate a dedicated particle detector for the inspection of harbor containers to hinder the smuggling of nuclear materials. Clustering techniques, working directly on scattering points, help to detect the presence of suspicious items inside the container, acting, as it will be shown, as a filter for a preliminary analysis of the data.

  11. The Muon Portal Project: A large-area tracking detector for muon tomography

    Directory of Open Access Journals (Sweden)

    Riggi F.

    2016-01-01

    Full Text Available The Muon Portal Project [1] is a joint initiative between research and industrial partners, aimed at the construction of a real size detector protoype to search for hidden high-Z fissile materials inside containers by the muon scattering technique. The detector is based on a set of 48 detection modules (1 m × 3 m, so as to provide four X-Y detection planes, two placed above and two below the container to be inspected. After a research and development phase, which led to the choice and test of the individual components, the construction of the full size detector has already started and will be completed in a few months.

  12. Comparison of primary tumour volumes delineated on four-dimensional computed tomography maximum intensity projection and 18F-fluorodeoxyglucose positron emission tomography computed tomography images of non-small cell lung cancer

    International Nuclear Information System (INIS)

    Duan, Yili; Li, Jianbin; Zhang, Yingjie; Wang, Wei; Fan, Tingyong; Shao, Qian; Xu, Min; Guo, Yanluan; Sun, Xiaorong; Shang, Dongping

    2015-01-01

    The study aims to compare the positional and volumetric differences of tumour volumes based on the maximum intensity projection (MIP) of four-dimensional CT (4DCT) and 18 F-fluorodexyglucose ( 18 F-FDG) positron emission tomography CT (PET/CT) images for the primary tumour of non-small cell lung cancer (NSCLC). Ten patients with NSCLC underwent 4DCT and 18 F-FDG PET/CT scans of the thorax on the same day. Internal gross target volumes (IGTVs) of the primary tumours were contoured on the MIP images of 4DCT to generate IGTV MIP . Gross target volumes (GTVs) based on PET (GTV PET ) were determined with nine different threshold methods using the auto-contouring function. The differences in the volume, position, matching index (MI) and degree of inclusion (DI) of the GTV PET and IGTV MIP were investigated. In volume terms, GTV PET2.0 and GTV PET20% approximated closely to IGTV MIP with mean volume ratio of 0.93 ± 0.45 and 1.06 ± 0.43, respectively. The best MI was between IGTV MIP and GTV PET20% (0.45 ± 0.23). The best DI of IGTV MIP in GTV PET was IGTV MIP in GTV PET20% (0.61 ± 0.26). In 3D PET images, the GTVPET contoured by standardised uptake value (SUV) 2.0 or 20% of maximal SUV (SUV max ) approximate closely to the IGTV MIP in target size, while the spatial mismatch is apparent between them. Therefore, neither of them could replace IGTV MIP in spatial position and form. The advent of 4D PET/CT may improve the accuracy of contouring the perimeter for moving targets.

  13. 12 CFR 334.23 - Contents of opt-out notice; consolidated and equivalent notices.

    Science.gov (United States)

    2010-01-01

    ... of the joint consumers may exercise the right to opt out. (ii) The opt-out notice must explain how an...) Alternative contents. If the consumer is afforded a broader right to opt out of receiving marketing than is... a clear, conspicuous, and concise notice that accurately discloses the consumer's opt-out rights. (4...

  14. 12 CFR 222.23 - Contents of opt-out notice; consolidated and equivalent notices.

    Science.gov (United States)

    2010-01-01

    ... consumers. Any of the joint consumers may exercise the right to opt out. (ii) The opt-out notice must...) Alternative contents. If the consumer is afforded a broader right to opt out of receiving marketing than is... a clear, conspicuous, and concise notice that accurately discloses the consumer's opt-out rights. (4...

  15. 40 CFR 96.85 - NOX Budget opt-in permit contents.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget opt-in permit contents. 96... (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.85 NOX Budget opt-in permit contents. (a) Each NOX Budget opt-in permit...

  16. 40 CFR 97.85 - NOX Budget opt-in permit contents.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false NOX Budget opt-in permit contents. 97... (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.85 NOX Budget opt-in permit contents. (a) Each NOX Budget opt-in permit will contain all elements...

  17. 40 CFR 97.83 - Applying for NOX Budget opt-in permit.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Applying for NOX Budget opt-in permit... PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS Individual Unit Opt-ins. § 97.83 Applying for NOX Budget opt-in permit. (a) Applying for initial NO X Budget opt...

  18. Long-Term Safety and Effectiveness of the “OptEase” Vena Cava Filter

    International Nuclear Information System (INIS)

    Kalva, Sanjeeva P.; Marentis, Theodore C.; Yeddula, Kalpana; Somarouthu, Bhanusupriya; Wicky, Stephan; Stecker, Michael S.

    2011-01-01

    Purpose: To assess the long-term safety and effectiveness of the OptEase inferior vena cava (IVC) filter. Materials and Methods: In this Institutional Review Board-approved, retrospective study, we reviewed data of 71 patients who received an OptEase filter at our institution from 2002 to 2007. Thirty-nine (55%) patients had symptoms of venous thromboembolism before filter placement. The indications for filter included contraindication to anticoagulation in 31 (44%) patients, prophylaxis against pulmonary embolism (PE) in 29 (41%) patients, and failure of anticoagulation in 11 (15%) patients. Procedure-related complications, such as symptomatic post-filter PE, deep venous thrombosis (DVT), IVC occlusion, and incidental imaging-evident filter-related complications, were recorded. Safety was assessed by the occurrence of filter-related complications during placement and follow-up. Effectiveness was assessed by the occurrence of post-filter PE. Results: Sixty-five (92%) filters were placed under fluoroscopy, and 6 (8%) were placed using intravascular ultrasound guidance. Seventy (99%) filters were placed successfully. Seven (10%) filters were placed in the suprarenal cava. Retrieval was attempted in 14 (20%) patients, and 12 filters were successfully retrieved. Clinical follow-up was available for 20 ± 21 months. Symptoms of postfilter PE and DVT occurred in 15% (n = 11) and 10% (n = 7) patients, respectively. None of these patients had computed tomography (CT)-proven PE, and only one had ultrasound-proven new DVT. One patient had symptomatic IVC occlusion. Follow-up abdominal CT in 20 patients showed thrombus in the filter in two of them. There were no instances of filter migration, filter tilt, or caval wall penetration. Conclusion: The OptEase filter appears to have an acceptable long-term safety profile. The filter was effective against PE.

  19. Difficult OptEase Filter Retrievals After Prolonged Indwelling Times

    Energy Technology Data Exchange (ETDEWEB)

    Van Ha, Thuong G., E-mail: tgvanha@radiology.bsd.uchicago.edu; Kang, Lisa; Lorenz, Jonathan; Zangan, Steven; Navuluri, Rakesh; Straus, Christopher; Funaki, Brian [University of Chicago, Section of Interventional Radiology, Department of Radiology (United States)

    2013-08-01

    PurposeThe OptEase vena cave filter (Cordis, Piscataway, NJ) is commercially available as a retrievable or permanent filter with short recommended indwelling time, presumably due to extensive contact of the filter side struts with the inferior vena cava wall and subsequent neointimal hyperplasia leading to incorporation. Our purpose was to evaluate OptEase filter retrievals with a long indwelling time period that required unconventional retrieval techniques.Materials and MethodsWe retrospectively reviewed patients who underwent OptEase filter retrieval with long undwelling times requiring additional maneuvers for retrieval. Techniques used included rigid endobronchial forceps dissection and wire-through-loop snare. Each patient underwent postretrieval venogram to evaluate for possible complications. In addition, patients had clinical follow-up 2 weeks after the retrieval procedure.ResultsThere were three patients (2 women, 1 man; average age 64 years) who underwent OptEase filter retrieval. The mean indwelling time was 6.4 months. The indwelling filters were successfully retrieved. There were no complications. Postprocedural follow-up showed no clinical pathology.ConclusionUnconventional techniques aided in the retrieval of OptEase filters with long indwelling times.

  20. Difficult OptEase Filter Retrievals After Prolonged Indwelling Times

    International Nuclear Information System (INIS)

    Van Ha, Thuong G.; Kang, Lisa; Lorenz, Jonathan; Zangan, Steven; Navuluri, Rakesh; Straus, Christopher; Funaki, Brian

    2013-01-01

    PurposeThe OptEase vena cave filter (Cordis, Piscataway, NJ) is commercially available as a retrievable or permanent filter with short recommended indwelling time, presumably due to extensive contact of the filter side struts with the inferior vena cava wall and subsequent neointimal hyperplasia leading to incorporation. Our purpose was to evaluate OptEase filter retrievals with a long indwelling time period that required unconventional retrieval techniques.Materials and MethodsWe retrospectively reviewed patients who underwent OptEase filter retrieval with long undwelling times requiring additional maneuvers for retrieval. Techniques used included rigid endobronchial forceps dissection and wire-through-loop snare. Each patient underwent postretrieval venogram to evaluate for possible complications. In addition, patients had clinical follow-up 2 weeks after the retrieval procedure.ResultsThere were three patients (2 women, 1 man; average age 64 years) who underwent OptEase filter retrieval. The mean indwelling time was 6.4 months. The indwelling filters were successfully retrieved. There were no complications. Postprocedural follow-up showed no clinical pathology.ConclusionUnconventional techniques aided in the retrieval of OptEase filters with long indwelling times

  1. Optimizing Opt-Out Consent for Record Linkage

    Directory of Open Access Journals (Sweden)

    Das Marcel

    2014-09-01

    Full Text Available This article reports on a study testing the effects of different ways of administering an opt-out consent for record linkage in a probability-based Internet panel. First, we conducted cognitive interviews to explore reactions to a draft version of the opt-out consent text. Second, we conducted a two-factor experiment to test the effects of content manipulations and mode. The results indicate that the way in which respondents were informed did not have much effect on opting out. Results from a follow-up survey on attitudes regarding privacy, confidentiality, and trust, along with knowledge questions about the process of linking, showed no evidence that presenting the opt-out consent statement makes respondents more concerned about privacy. Knowledge about the aspects of record linkage is generally not high. When looking at long-term effects of sending an opt-out consent statement, we found no evidence that this leads to higher attrition or lower participation rates.

  2. Contemporary hygienic and engineering requirements to the projecting and exploitation of the positron-emission tomography in medicine

    International Nuclear Information System (INIS)

    Chekmarev, O.; Paltseva, A.

    2004-01-01

    The positron-emission tomography (PET) centres, attached to a large medical establishment as a rule include except PET a compact cyclotron for producing positron-radiant ultra-temporary product radionuclides (carbon-11, Nitrogen-14, oxygen-15, fluorine-18 and etc.) based on water and gaseous targets. At present there are no information about regulating and setting up such medical centres, moreover, requirements which must be presented to the Sanitary Inspection Agency at the documents examination are incompletely represented. During 2001-2003 years specialists of the Moscow Medical Centre (MMC) have been reviewing the hygienic expert examination of the 5 versions of the PET's cabinets installation in therapeutic and prophylactic offices. One of the projects for operating ultra-temporary products is submitted in this report. It foresees the usage of proton beam of the self-protected cyclotron RDS/111 (CTJ PET System (USA)). Its energy of irradiation (proton beam) is 11 MeV. The cyclotron is placed in the additional building of the radiological trunk on the territory of the Moscow Clinical hospital. The technological process of producing the ultra-temporary radionuclides is presented. The block of the radiodiagnostic research include: a treatment room for PET; an operating room; an area for information handling; a treatment room for intake of the radio-pharm-preparations; a filling room; a laboratory for express-analysis of blood before and after research; a WC for patients (with radio-pharm-preparations); and at last - an area for transient (30 - 40 min.) staying for the patients in the lay position before the research. All probable accidents, which can happen in the case of any technology violation, are discussed. There were worked out special requirements to the clarification tanks equipment for liquid radioactive waste and to the time of being a patient in the department after diagnostic researches using fluorine-18

  3. Polynomial reconstruction of radial catalyst concentration distribution in an experimental type FCC riser for a low number of transversal projections in gamma ray tomography

    International Nuclear Information System (INIS)

    Melo, Silvio B.; Simoes, Francisco P.M.; Oliveira, Eric F. de; Santos, Maria das Gracas dos; Dantas, Carlos C.

    2007-01-01

    In the FCC - Fluid Catalytic Cracking process the Riser is an opaque cylinder, so that, in order to investigate the catalyst concentration inside, a gamma- ray based tomography is employed. Each section is submitted to a parallel beam and by means of the Beer-Lambert transmission is calculated. This tomography session is repeated from different angles, in manual tomographic experiments where the source/detector pair is rotated, producing in each direction what we called a transversal projection. In order to reconstruct the concentration of the present catalyst in a given moment some methods use successfully the inverse Radon transform through the filtered back-projection algorithm. The results are fully satisfactory for a large number of projections, widely seen as better than those produced by the algebraic methods. For a low number of projections, however, the algebraic methods become more competitive. In practice, simple experimental set-ups work with less than 10 projections, due to the time taken by the whole process. In this work, we present an investigation of polynomial reconstructions by using Bezier surfaces of arbitrary degree, adjusted to the experimental data through a least squares method. A computational algorithm was developed to implement the mathematical reconstruction for the 3D graphics presentation. (author)

  4. Poster — Thur Eve — 01: The effect of the number of projections on MTF and CNR in Compton scatter tomography

    International Nuclear Information System (INIS)

    Chighvinadze, T; Pistorius, S

    2014-01-01

    Purpose: To investigate the dependence of the reconstructed image quality on the number of projections in multi-projection Compton scatter tomography (MPCST). The conventional relationship between the projection number used for reconstruction and reconstructed image quality pertained to CT does not necessarily apply to MPCST, which can produce images from a single projection if the detectors have sufficiently high energy and spatial resolution. Methods: The electron density image was obtained using filtered-backprojection of the scatter signal over circular arcs formed using Compton equation. The behavior of the reconstructed image quality as a function of the projection number was evaluated through analytical simulations and characterized by CNR and MTF. Results: The increase of the projection number improves the contrast with this dependence being a function of fluence. The number of projections required to approach the asymptotic maximum contrast decreases as the fluence increases. Increasing projection number increases the CNR but not spatial resolution. Conclusions: For MPCST using a 500eV energy resolution and a 2×2mm 2 size detector, an adequate image quality can be obtained with a small number of projections provided the incident fluence is high enough. This is conceptually different from conventional CT where a minimum number of projections is required to obtain an adequate image quality. While increasing projection number, even for the lowest dose value, the CNR increases even though the number of photons per projection decreases. The spatial resolution of the image is improved by increasing the sampling within a projection rather than by increasing the number of projections

  5. Meaning of Interior Tomography

    Science.gov (United States)

    Wang, Ge; Yu, Hengyong

    2013-01-01

    The classic imaging geometry for computed tomography is for collection of un-truncated projections and reconstruction of a global image, with the Fourier transform as the theoretical foundation that is intrinsically non-local. Recently, interior tomography research has led to theoretically exact relationships between localities in the projection and image spaces and practically promising reconstruction algorithms. Initially, interior tomography was developed for x-ray computed tomography. Then, it has been elevated as a general imaging principle. Finally, a novel framework known as “omni-tomography” is being developed for grand fusion of multiple imaging modalities, allowing tomographic synchrony of diversified features. PMID:23912256

  6. Sacrificio cortoplacista adaptativo 2opt (SCA_2opt: Una heurística inspirada en el pensamiento sistémico Sacrifice short-term adaptive 2-opt (SCA_2opt: A heuristic inspired by systems thinking

    Directory of Open Access Journals (Sweden)

    Jorge Pérez Rave

    2013-01-01

    Full Text Available Se detalla el origen de dos noveles heurísticas para el TSP simétrico, inspiradas en el pensamiento sistémico: Sacrificio Cortoplacista Adaptativo 2-opt (SCA_2opt y SCA_2_opt_r. Estas surgen del análisis sistémico de la regla de decisión Vecino más cercano, identificándosele el arquetipo "Soluciones contraproducentes". El SCA se basa en que el agente viajero renuncie en un momento dado a una ciudad inmediatamente cercana, y se traslade hacia la segunda ciudad más cercana disponible. A partir de ello, se continúa con la regla del vecino más cercano. Cada que se realiza el SCA (búsqueda global se efectúa una búsqueda local 2_opt. Considerando el binomio eficacia y eficiencia, las dos heurísticas se muestran prometedoras en comparación multicriterio contra 19 metaheurísticas. Se evidencia que el pensamiento sistémico es un campo de inspiración viable para el desarrollo de métodos de optimización combinatoria; se plasman preguntas emergentes para desarrollos futuros, que permitan continuar integrando elementos de la optimización clásica con el pensamiento sistémico; áreas tradicionalmente vistas como antagónicas, pero cuyo diálogo se muestra favorable en este artículo.Outlining two novice heuristics for the symmetric TSP, inspired systemic thinking: Sacrifice short-term adaptive 2-opt (SCA2opt and SCA_2opt_r. These arise from the systemic analysis of the rule of decision, nearest neighbour, identifying the archetype "Counterproductive solutions". SCA relies on that agent traveler, renounces at any given time immediately to a nearby city, and moves towards the second nearest available city. From there, it continues with the nearest neighbour rule. Each is the SCA (global search operates a local search 2opt. Where as the binomial effectiveness and efficiency, the two new heuristics are shown promising in comparison multicriteria against 19 metaheuristics. It is evident that systemic thinking is a field of inspiration viable

  7. No opt-out is forever. Sweden opts back in; Ausstieg ist nie endgueltig. Schweden kehrt um

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Horst

    2010-06-15

    The draft legislation by the conservative-liberal Swedish government of early 2010, which was adopted by the Swedish parliament on June 17, 2010, not only repeals the shutdown of all Swedish nuclear power plants, which had earlier been foreseen by this year, but permits the construction and operation of new plants. In Sweden, a referendum in 1980 started the opt-out process. Shutdown within 30 years was foreseen in the regulation. As early as in late 1995, an Energy Committee appointed by the government reported that a complete opt-out by 2010 was impossible to achieve on economic and environmental grounds. Under the 1997 Opt-out Act, the government may shut down nuclear power plants at any time against an indemnification - unlike Germany. Another prerequisite is the realistic availability of new energy sources. As a consequence, only 2 nuclear power plants have been shut down so far, mainly because of protests from neighboring Denmark. Thirty years after the referendum, the acceptance of nuclear power in Sweden is high and stable. In line with growing public acceptance in the course of the debate about climate change, the Christian-Democratic Party changed its policy in March 2007, opting out of the opt-out. Finally, the conservative-liberal Swedish government submitted draft legislation to parliament which also permitted building new nuclear power plants. The Social Democratic Workers' Party, which is in the opposition, stuck to its rejection of the use of nuclear power and announced its intention to reverse the repeal of the opt-out in September 2010, after parliamentary elections and a possible new red-green government. The public and political developments in Sweden show that social attitudes towards nuclear power, opt-out policies and legal regulations can change. Adopting a rational attitude when discussing nuclear power and realities is possible, and political views sooner or later will adapt to the new situation. This could happen also in Germany

  8. Doppler Tomography

    Science.gov (United States)

    Marsh, T. R.

    I review the method of Doppler tomography which translates binary-star line profiles taken at a series of orbital phases into a distribution of emission over the binary. I begin with a discussion of the basic principles behind Doppler tomography, including a comparison of the relative merits of maximum entropy regularisation versus filtered back-projection for implementing the inversion. Following this I discuss the issue of noise in Doppler images and possible methods for coping with it. Then I move on to look at the results of Doppler Tomography applied to cataclysmic variable stars. Outstanding successes to date are the discovery of two-arm spiral shocks in cataclysmic variable accretion discs and the probing of the stream/magnetospheric interaction in magnetic cataclysmic variable stars. Doppler tomography has also told us much about the stream/disc interaction in non-magnetic systems and the irradiation of the secondary star in all systems. The latter indirectly reveals such effects as shadowing by the accretion disc or stream. I discuss all of these and finish with some musings on possible future directions for the method. At the end I include a tabulation of Doppler maps published in refereed journals.

  9. 17 CFR 248.127 - Renewal of opt out elections.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) REGULATIONS S-P AND S-AM Regulation S-AM: Limitations on Affiliate Marketing § 248.127 Renewal of... expires, you may not make marketing solicitations to a consumer who previously opted out, unless: (i) The....122(b). (3) Affiliates who may provide the notice. The notice required by this paragraph must be...

  10. 16 CFR 680.24 - Reasonable opportunity to opt out.

    Science.gov (United States)

    2010-01-01

    ..., such as by posting the notice at an Internet Web site at which the consumer has obtained a product or... conducted on an Internet Web site. The consumer is required to decide, as a necessary part of proceeding... including in a privacy notice. The opt-out notice is included in a Gramm-Leach-Bliley Act privacy notice...

  11. A parallel 2-opt algorithm for the traveling salesman problem

    NARCIS (Netherlands)

    Verhoeven, M.G.A.; Aarts, E.H.L.; Swinkels, P.C.J.

    1995-01-01

    We present a scalable parallel local search algorithm based on data parallelism. The concept of distributed neighborhood structures is introduced, and applied to the Traveling Salesman Problem (TSP). Our parallel local search algorithm finds the same quality solutions as the classical 2-opt

  12. 12 CFR 571.27 - Renewal of opt-out.

    Science.gov (United States)

    2010-01-01

    ... period. Each opt-out renewal must be effective for a period of at least five years as provided in § 571... (ii) As part of a joint renewal notice from two or more members of an affiliated group of companies... provided by multiple companies with the ABC name or multiple companies in the ABC group or family of...

  13. 12 CFR 717.24 - Reasonable opportunity to opt out.

    Science.gov (United States)

    2010-01-01

    ... completing a form that requires consumers to write a “yes” or “no” to indicate their opt-out preference or.... You must not use eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the consumer is provided a reasonable...

  14. 12 CFR 41.24 - Reasonable opportunity to opt out.

    Science.gov (United States)

    2010-01-01

    ... completing a form that requires consumers to write a “yes” or “no” to indicate their opt-out preference or... eligibility information about a consumer that it receives from an affiliate to make a solicitation to the consumer about the bank's products or services, unless the consumer is provided a reasonable opportunity to...

  15. 12 CFR 334.24 - Reasonable opportunity to opt out.

    Science.gov (United States)

    2010-01-01

    ...” to indicate their opt-out preference or that requires the consumer to check one of two blank check...) In general. You must not use eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the consumer is...

  16. The OptIPuter microscopy demonstrator: enabling science through a transatlantic lightpath

    Science.gov (United States)

    Ellisman, M.; Hutton, T.; Kirkland, A.; Lin, A.; Lin, C.; Molina, T.; Peltier, S.; Singh, R.; Tang, K.; Trefethen, A.E.; Wallom, D.C.H.; Xiong, X.

    2009-01-01

    The OptIPuter microscopy demonstrator project has been designed to enable concurrent and remote usage of world-class electron microscopes located in Oxford and San Diego. The project has constructed a network consisting of microscopes and computational and data resources that are all connected by a dedicated network infrastructure using the UK Lightpath and US Starlight systems. Key science drivers include examples from both materials and biological science. The resulting system is now a permanent link between the Oxford and San Diego microscopy centres. This will form the basis of further projects between the sites and expansion of the types of systems that can be remotely controlled, including optical, as well as electron, microscopy. Other improvements will include the updating of the Microsoft cluster software to the high performance computing (HPC) server 2008, which includes the HPC basic profile implementation that will enable the development of interoperable clients. PMID:19487201

  17. The OptIPuter microscopy demonstrator: enabling science through a transatlantic lightpath.

    Science.gov (United States)

    Ellisman, M; Hutton, T; Kirkland, A; Lin, A; Lin, C; Molina, T; Peltier, S; Singh, R; Tang, K; Trefethen, A E; Wallom, D C H; Xiong, X

    2009-07-13

    The OptIPuter microscopy demonstrator project has been designed to enable concurrent and remote usage of world-class electron microscopes located in Oxford and San Diego. The project has constructed a network consisting of microscopes and computational and data resources that are all connected by a dedicated network infrastructure using the UK Lightpath and US Starlight systems. Key science drivers include examples from both materials and biological science. The resulting system is now a permanent link between the Oxford and San Diego microscopy centres. This will form the basis of further projects between the sites and expansion of the types of systems that can be remotely controlled, including optical, as well as electron, microscopy. Other improvements will include the updating of the Microsoft cluster software to the high performance computing (HPC) server 2008, which includes the HPC basic profile implementation that will enable the development of interoperable clients.

  18. Compatibility with European law of opt-out legislation

    International Nuclear Information System (INIS)

    Feldmann, U.

    2000-01-01

    Should consensus with the utilities not be reached, Federal Minister for the Environment, Mr. Trittin, repeatedly announced to introduce opt-out legislation 'by dissent'. Both the constitutionality of such legislation and its compatibility with European law are topics of controversial debate in the literature. The decision taken by the Bavarian cabinet on February 8 in this year, to use all political and legal means against shutting down German nuclear power plants and, for this purpose, even to approach the European Commission on grounds of potential violation of European law, are reason enough to deal in more detail with the compatibility of an opt-out law with the Euratom Treaty and the EC Treaty. As the opt-out law does not yet exist, these considerations can only be of a theoretical nature. However, this is the working hypothesis assumed: Reprocessing is banned as of the entry into force of the opt-out law. This ban includes moving nuclear waste abroad for reprocessing. The peaceful use of nuclear power for electricity generation in power reactors operated for thirty years is forbidden. Older reactors may be run only for a transition period of another three years. (This includes abandoning the promotion purpose in the German Atomic Energy Act and a ban on building new power reactors). However, the operating life may be distributed in a flexible way. This contribution indicates that there are sound reasons and interesting approaches, respectively, in the literature for assuming that opting out by means of legislation, coupled with a ban on reprocessing, at least constitutes a violation of the freedom for goods and/or services. However, this cannot be derived unequivocally from either the Euratom Treaty or the EC Treaty or from rulings by the European Court of Justice. Ultimately, compatibility with European law of the ban on reprocessing can be decided only by the European Court of Justice. (orig.) [de

  19. Opt-out donation and tacit consent: a reply to Wilkinson and De Wispelaere.

    Science.gov (United States)

    Saunders, Ben

    2012-02-01

    In this reply to Wilkinson and De Wispelaere, I argue that an opt-out donation system can be regarded as tacit consent. I first separate the opt-in/opt-out issue from that of the role that the family ought to play. I then argue that what De Wispelaere calls minimal approval-tracking is not obviously necessary and that, even if it were, opt-out schemes can satisfy this requirement.

  20. Assessment Opt-Out Policies: State Responses to Parent Pushback. ECS Education Trends

    Science.gov (United States)

    Aragon, Stephanie; Rowland, Julie; Wixom, Micah Ann

    2015-01-01

    With new state assessments kicking into full swing across the country, schools are seeing more and more parents wanting to opt out their children. Determining whether states allow assessment opt-outs can be complex and is constantly evolving. In some states the answer is clear: State policies either allow or prohibit state assessment opt-outs, or…

  1. Improving the ensemble optimization method through covariance matrix adaptation (CMA-EnOpt)

    NARCIS (Netherlands)

    Fonseca, R.M.; Leeuwenburgh, O.; Hof, P.M.J. van den; Jansen, J.D.

    2013-01-01

    Ensemble Optimization (EnOpt) is a rapidly emerging method for reservoir model based production optimization. EnOpt uses an ensemble of controls to approximate the gradient of the objective function with respect to the controls. Current implementations of EnOpt use a Gaussian ensemble with a

  2. Augmenting short cheap talk scripts with a repeated opt-out reminder in choice experiment surveys

    DEFF Research Database (Denmark)

    Ladenburg, Jacob; Olsen, Søren Bøye

    to choose the opt-out alternative if they find the experimentally designed alternatives too expensive. In an empirical Choice Experiment survey we find the Opt-Out Reminder to significantly reduce total WTP and to some extent also marginal WTP beyond the capability of the Cheap Talk applied without the Opt...

  3. 40 CFR 96.83 - Applying for NOX Budget opt-in permit.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Applying for NOX Budget opt-in permit... PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS Individual Unit Opt-ins § 96.83 Applying for NOX Budget opt-in permit. (a) Applying for...

  4. 12 CFR 717.22 - Scope and duration of opt-out.

    Science.gov (United States)

    2010-01-01

    ... CREDIT REPORTING Affiliate Marketing § 717.22 Scope and duration of opt-out. (a) Scope of opt-out. (1) In... as described in the notice to make solicitations to the consumer. (2) Continuing relationship. (i) In general. If the consumer establishes a continuing relationship with you or your affiliate, an opt-out...

  5. 16 CFR 680.21 - Affiliate marketing opt-out and exceptions.

    Science.gov (United States)

    2010-01-01

    ... marketing purposes to a consumer with whom you have a pre-existing business relationship; (2) To facilitate... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions... AFFILIATE MARKETING § 680.21 Affiliate marketing opt-out and exceptions. (a) Initial notice and opt-out...

  6. 12 CFR 571.22 - Scope and duration of opt-out.

    Science.gov (United States)

    2010-01-01

    ... REPORTING Affiliate Marketing § 571.22 Scope and duration of opt-out. (a) Scope of opt-out—(1) In general... described in the notice to make solicitations to the consumer. (2) Continuing relationship—(i) In general. If the consumer establishes a continuing relationship with you or your affiliate, an opt-out notice...

  7. 16 CFR 680.22 - Scope and duration of opt-out.

    Science.gov (United States)

    2010-01-01

    ... MARKETING § 680.22 Scope and duration of opt-out. (a) Scope of opt-out—(1) In general. Except as otherwise... make solicitations to the consumer. (2) Continuing relationship—(i) In general. If the consumer establishes a continuing relationship with you or your affiliate, an opt-out notice may apply to eligibility...

  8. 12 CFR 41.22 - Scope and duration of opt-out.

    Science.gov (United States)

    2010-01-01

    ... Affiliate Marketing § 41.22 Scope and duration of opt-out. (a) Scope of opt-out. (1) In general. Except as... the notice to make solicitations to the consumer. (2) Continuing relationship. (i) In general. If the consumer establishes a continuing relationship with a bank or its affiliate, an opt-out notice may apply to...

  9. 12 CFR 571.25 - Reasonable and simple methods of opting out.

    Science.gov (United States)

    2010-01-01

    ... CREDIT REPORTING Affiliate Marketing § 571.25 Reasonable and simple methods of opting out. (a) In general... out, such as a form that can be electronically mailed or processed at an Internet Web site, if the... (15 U.S.C. 6801 et seq.), the affiliate sharing opt-out under the Act, and the affiliate marketing opt...

  10. 16 CFR 680.25 - Reasonable and simple methods of opting out.

    Science.gov (United States)

    2010-01-01

    ... AFFILIATE MARKETING § 680.25 Reasonable and simple methods of opting out. (a) In general. You must not use... a form that can be electronically mailed or processed at an Internet Web site, if the consumer..., 15 U.S.C. 6801 et seq., the affiliate sharing opt-out under the Act, and the affiliate marketing opt...

  11. Electrical Impedance Tomography Technology

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal for the Electrical Impedance Tomography Technology (EITT) project is to develop a reliable portable, lightweight device providing two-dimensional...

  12. A randomised controlled trial to compare opt-in and opt-out parental consent for childhood vaccine safety surveillance using data linkage: study protocol

    OpenAIRE

    Berry, Jesia G; Ryan, Philip; Braunack-Mayer, Annette J; Duszynski, Katherine M; Xafis, Vicki; Gold, Michael S

    2011-01-01

    Abstract Background The Vaccine Assessment using Linked Data (VALiD) trial compared opt-in and opt-out parental consent for a population-based childhood vaccine safety surveillance program using data linkage. A subsequent telephone interview of all households enrolled in the trial elicited parental intent regarding the return or non-return of reply forms for opt-in and opt-out consent. This paper describes the rationale for the trial and provides an overview of the design and methods. Methods...

  13. Using 2-Opt based evolution strategy for travelling salesman problem

    Directory of Open Access Journals (Sweden)

    Kenan Karagul

    2016-03-01

    Full Text Available Harmony search algorithm that matches the (µ+1 evolution strategy, is a heuristic method simulated by the process of music improvisation. In this paper, a harmony search algorithm is directly used for the travelling salesman problem. Instead of conventional selection operators such as roulette wheel, the transformation of real number values of harmony search algorithm to order index of vertex representation and improvement of solutions are obtained by using the 2-Opt local search algorithm. Then, the obtained algorithm is tested on two different parameter groups of TSPLIB. The proposed method is compared with classical 2-Opt which randomly started at each step and best known solutions of test instances from TSPLIB. It is seen that the proposed algorithm offers valuable solutions.

  14. Joint project of the international network of agencies for health technology assessment--Part 1: Survey results on diffusion, assessment, and clinical use of positron emission tomography.

    Science.gov (United States)

    Hastings, John; Adams, Elizabeth J

    2006-01-01

    The International Network of Agencies for Health Technology Assessment (INAHTA) has been tracking activities associated with the clinical use of positron emission tomography (PET) in its members' healthcare systems since 1997 and published its first Joint Project report on PET in 1999. Part 1 of this Joint Project report presents survey results on diffusion, assessment activities, and policy for clinical use related to PET among INAHTA members since 1999. INAHTA members were surveyed in 2003-2004. Twenty-seven INAHTA agencies (69 percent response rate) from nineteen countries responded to the survey. Dedicated PET systems are the most universally installed systems to date. Mobile scanners and modified gamma cameras are used occasionally as lower cost alternatives, and interest in PET-computed tomography hybrid models is rising despite limited assessment of impact on service planning. PET was used and assessed most commonly for managing patients with cancer. All respondents reported having some form of public funding for clinical PET frequently linked to data collection for the purpose of gathering evidence to refine clinical use and guide resource allocation toward indications that maximize clinical and cost-effectiveness. The use of HTA within a continuous quality improvement framework can help optimize scarce resources for evaluation and use of high cost diagnostic technologies such as PET, particularly where potential clinical or cost-effectiveness is considerable but conclusive evidence is lacking.

  15. Optimization of Simulated Inventory Systems : OptQuest and Alternatives

    OpenAIRE

    Kleijnen, J.P.C.; Wan, J.

    2006-01-01

    This article illustrates simulation optimization through an (s, S) inventory manage- ment system. In this system, the goal function to be minimized is the expected value of speci…c inventory costs. Moreover, speci…c constraints must be satis…ed for some random simulation responses, namely the service or …ll rate, and for some determin- istic simulation inputs, namely the constraint s OptQuest method. The optimal...

  16. Prediction of optimal deployment projection for transcatheter aortic valve replacement: angiographic 3-dimensional reconstruction of the aortic root versus multidetector computed tomography.

    Science.gov (United States)

    Binder, Ronald K; Leipsic, Jonathon; Wood, David; Moore, Teri; Toggweiler, Stefan; Willson, Alex; Gurvitch, Ronen; Freeman, Melanie; Webb, John G

    2012-04-01

    Identifying the optimal fluoroscopic projection of the aortic valve is important for successful transcatheter aortic valve replacement (TAVR). Various imaging modalities, including multidetector computed tomography (MDCT), have been proposed for prediction of the optimal deployment projection. We evaluated a method that provides 3-dimensional angiographic reconstructions (3DA) of the aortic root for prediction of the optimal deployment angle and compared it with MDCT. Forty patients undergoing transfemoral TAVR at St Paul's Hospital, Vancouver, Canada, were evaluated. All underwent preimplant 3DA and 68% underwent preimplant MDCT. Three-dimensional angiographic reconstructions were generated from images of a C-arm rotational aortic root angiogram during breath-hold, rapid ventricular pacing, and injection of 32 mL contrast medium at 8 mL/s. Two independent operators prospectively predicted perpendicular valve projections. The implant angle was chosen at the discretion of the physician performing TAVR. The angles from 3DA, from MDCT, the implant angle, and the postdeployment perpendicular prosthesis view were compared. The shortest distance from the postdeployment perpendicular prosthesis projection to the regression line of predicted perpendicular projections was calculated. All but 1 patient had adequate image quality for reproducible angle predictions. There was a significant correlation between 3DA and MDCT for prediction of perpendicular valve projections (r=0.682, Pregression line of predicted angles to the postdeployment prosthesis view was 5.1±4.6° for 3DA and 7.9±4.9° for MDCT (P=0.01). Three-dimensional angiographic reconstructions and MDCT are safe, practical, and accurate imaging modalities for identifying the optimal perpendicular valve deployment projection during TAVR.

  17. Binary moving-blocker-based scatter correction in cone-beam computed tomography with width-truncated projections: proof of concept

    Science.gov (United States)

    Lee, Ho; Fahimian, Benjamin P.; Xing, Lei

    2017-03-01

    This paper proposes a binary moving-blocker (BMB)-based technique for scatter correction in cone-beam computed tomography (CBCT). In concept, a beam blocker consisting of lead strips, mounted in front of the x-ray tube, moves rapidly in and out of the beam during a single gantry rotation. The projections are acquired in alternating phases of blocked and unblocked cone beams, where the blocked phase results in a stripe pattern in the width direction. To derive the scatter map from the blocked projections, 1D B-Spline interpolation/extrapolation is applied by using the detected information in the shaded regions. The scatter map of the unblocked projections is corrected by averaging two scatter maps that correspond to their adjacent blocked projections. The scatter-corrected projections are obtained by subtracting the corresponding scatter maps from the projection data and are utilized to generate the CBCT image by a compressed-sensing (CS)-based iterative reconstruction algorithm. Catphan504 and pelvis phantoms were used to evaluate the method’s performance. The proposed BMB-based technique provided an effective method to enhance the image quality by suppressing scatter-induced artifacts, such as ring artifacts around the bowtie area. Compared to CBCT without a blocker, the spatial nonuniformity was reduced from 9.1% to 3.1%. The root-mean-square error of the CT numbers in the regions of interest (ROIs) was reduced from 30.2 HU to 3.8 HU. In addition to high resolution, comparable to that of the benchmark image, the CS-based reconstruction also led to a better contrast-to-noise ratio in seven ROIs. The proposed technique enables complete scatter-corrected CBCT imaging with width-truncated projections and allows reducing the acquisition time to approximately half. This work may have significant implications for image-guided or adaptive radiation therapy, where CBCT is often used.

  18. 3D computed tomography using a microfocus X-ray source: Analysis of artifact formation in the reconstructed images using simulated as well as experimental projection data

    International Nuclear Information System (INIS)

    Krimmel, S.; Stephan, J.; Baumann, J.

    2005-01-01

    The scope of this contribution is to identify and to quantify the influence of different parameters on the formation of image artifacts in X-ray computed tomography (CT) resulting for example, from beam hardening or from partial lack of information using 3D cone beam CT. In general, the reconstructed image quality depends on a number of acquisition parameters concerning the X-ray source (e.g. X-ray spectrum), the geometrical setup (e.g. cone beam angle), the sample properties (e.g. absorption characteristics) and the detector properties. While it is difficult to distinguish the influence of different effects clearly in experimental projection data, they can be selected individually with the help of simulated projection data by varying the parameter set. The reconstruction of the 3D data set is performed with the filtered back projection algorithm according to Feldkamp, Davis and Kress for experimental as well as for simulated projection data. The experimental data are recorded with an industrial microfocus CT system which features a focal spot size of a few micrometers and uses a digital flat panel detector for data acquisition

  19. Computed tomography of surface related radionuclide distributions ('BONN'-tomography)

    International Nuclear Information System (INIS)

    Bockisch, A.; Koenig, R.

    1989-01-01

    A method called the 'BONN' tomography is described to produce planar projections of circular activity distributions using standard single photon emission computed tomography. The clinical value of the method is demonstrated for bone scans of the jaw, thorax, and pelvis. Numerical or projection-related problems are discussed. (orig.) [de

  20. A randomised controlled trial to compare opt-in and opt-out parental consent for childhood vaccine safety surveillance using data linkage: study protocol

    Directory of Open Access Journals (Sweden)

    Duszynski Katherine M

    2011-01-01

    Full Text Available Abstract Background The Vaccine Assessment using Linked Data (VALiD trial compared opt-in and opt-out parental consent for a population-based childhood vaccine safety surveillance program using data linkage. A subsequent telephone interview of all households enrolled in the trial elicited parental intent regarding the return or non-return of reply forms for opt-in and opt-out consent. This paper describes the rationale for the trial and provides an overview of the design and methods. Methods/Design Single-centre, single-blind, randomised controlled trial (RCT stratified by firstborn status. Mothers who gave birth at one tertiary South Australian hospital were randomised at six weeks post-partum to receive an opt-in or opt-out reply form, along with information explaining data linkage. The primary outcome at 10 weeks post-partum was parental participation in each arm, as indicated by the respective return or non-return of a reply form (or via telephone or email response. A subsequent telephone interview at 10 weeks post-partum elicited parental intent regarding the return or non-return of the reply form, and attitudes and knowledge about data linkage, vaccine safety, consent preferences and vaccination practices. Enrolment began in July 2009 and 1,129 households were recruited in a three-month period. Analysis has not yet been undertaken. The participation rate and selection bias for each method of consent will be compared when the data are analysed. Discussion The VALiD RCT represents the first trial of opt-in versus opt-out consent for a data linkage study that assesses consent preferences and intent compared with actual opting in or opting out behaviour, and socioeconomic factors. The limitations to generalisability are discussed. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12610000332022

  1. A randomised controlled trial to compare opt-in and opt-out parental consent for childhood vaccine safety surveillance using data linkage: study protocol.

    Science.gov (United States)

    Berry, Jesia G; Ryan, Philip; Braunack-Mayer, Annette J; Duszynski, Katherine M; Xafis, Vicki; Gold, Michael S

    2011-01-04

    The Vaccine Assessment using Linked Data (VALiD) trial compared opt-in and opt-out parental consent for a population-based childhood vaccine safety surveillance program using data linkage. A subsequent telephone interview of all households enrolled in the trial elicited parental intent regarding the return or non-return of reply forms for opt-in and opt-out consent. This paper describes the rationale for the trial and provides an overview of the design and methods. Single-centre, single-blind, randomised controlled trial (RCT) stratified by firstborn status. Mothers who gave birth at one tertiary South Australian hospital were randomised at six weeks post-partum to receive an opt-in or opt-out reply form, along with information explaining data linkage. The primary outcome at 10 weeks post-partum was parental participation in each arm, as indicated by the respective return or non-return of a reply form (or via telephone or email response). A subsequent telephone interview at 10 weeks post-partum elicited parental intent regarding the return or non-return of the reply form, and attitudes and knowledge about data linkage, vaccine safety, consent preferences and vaccination practices. Enrolment began in July 2009 and 1,129 households were recruited in a three-month period. Analysis has not yet been undertaken. The participation rate and selection bias for each method of consent will be compared when the data are analysed. The VALiD RCT represents the first trial of opt-in versus opt-out consent for a data linkage study that assesses consent preferences and intent compared with actual opting in or opting out behaviour, and socioeconomic factors. The limitations to generalisability are discussed. Australian New Zealand Clinical Trials Registry ACTRN12610000332022.

  2. Presentations from the Aeroelastic Workshop - latest results from AeroOpt

    Energy Technology Data Exchange (ETDEWEB)

    Hartvig Hansen, M. (ed.)

    2011-10-15

    This report contains the slides of the presentations at the Aeroelastic Workshop held at Risoe-DTU for the wind energy industry in Denmark on October 27, 2011. The scientific part of the agenda at this workshop was 1) Detailed and reduced models of dynamic mooring system (Anders M. Hansen). 2) Bend-twist coupling investigation in HAWC2 (Taeseong Kim). 3) Q3UIC - A new aerodynamic airfoil tool including rotational effects (Nestor R. Garcia). 4) Influence of up-scaling on loads, control and aerodynamic modeling (Helge Aa. Madsen). 5) Aerodynamic damping of lateral tower vibrations (Bjarne S. Kallesoee). 6) Open- and closed-loop aeroservoelastic analysis with HAWCStab2 (Morten H. Hansen). 7) Design and test of a thick, flatback, high-lift multielement airfoil (Frederik Zahle). The presented results are mainly obtained in the EUDP project ''Aeroelastic Optimization of MW Wind Turbines (AeroOpt)''. (Author)

  3. Computed tomography device

    International Nuclear Information System (INIS)

    Ohhashi, A.

    1985-01-01

    A computed tomography device comprising a subtraction unit which obtains differential data strings representing the difference between each time-serial projection data string of a group of projection data strings corresponding to a prospective reconstruction image generated by projection data strings acquired by a data acquisition system, a convolution unit which convolves each time-serial projection data string of the group of projection data strings corresponding to the prospective reconstruction image, and a back-projection unit which back-projects the convolved data strings

  4. Effect of ranibizumab on high-speed indocyanine green angiography and minimum intensity projection optical coherence tomography findings in neovascular age-related macular degeneration.

    Science.gov (United States)

    Nicholson, Benjamin P; Nigam, Divya; Toy, Brian; Stetson, Paul F; Agrón, Elvira; Jacobs-El, Naima; Cunningham, Denise; Cukras, Catherine; Wong, Wai; Wiley, Henry; Chew, Emily; Ferris, Frederick; Meyerle, Catherine B

    2015-01-01

    The purpose of this 1-year prospective study was to investigate how induction/pro re nata ranibizumab intravitreal treatment of eyes with neovascular age-related macular degeneration affects the anatomy of choroidal neovascularization (CNV) and the overlying outer retinal tissue. High-speed indocyanine green (HS-ICG) angiography measurements provided quantification of the CNV size in 60 patients followed for 1 year. Minimum intensity projection optical coherence tomography (MinIP OCT), a novel algorithm assessing minimum optical intensity between the internal limiting membrane and retinal pigment epithelium, measured the area of outer retinal disruption overlying the CNV. Fluorescein angiography was also assessed to evaluate late retinal leakage. After 1 year, the mean area of CNV measured with indocyanine green angiography decreased by 5.8%. The mean area of MinIP OCT of outer retinal disruption overlying the CNV decreased by 4.2%. Mean area of fluorescein angiography leakage decreased by 6.3%. Both the area of outer retinal disruption measured with MinIP OCT and the area of leakage on fluorescein angiography typically exceeded the area of CNV on indocyanine green angiography at baseline and 1 year. Choroidal neovascularization treated with induction/pro re nata intravitreal ranibizumab for 1 year essentially remained static. Minimum intensity projection optical coherence tomography suggests that the area of outer retinal disruption overlying the CNV may be greater than the CNV itself and often correlates with the leakage area on fluorescein angiography. Additionally, there was minimal change in the area of outer retinal disruption on MinIP OCT even when fluid resolved. Measurements of the extent of CNV lesions based on indocyanine green angiography and MinIP OCT may provide useful outcome variables to help assess the CNV complex longitudinally and warrant further validation.

  5. WE-G-BRF-05: Feasibility of Markerless Motion Tracking Using Dual Energy Cone Beam Computed Tomography (DE-CBCT) Projections

    International Nuclear Information System (INIS)

    Panfil, J; Patel, R; Surucu, M; Roeske, J

    2014-01-01

    Purpose: To compare markerless template-based tracking of lung tumors using dual energy (DE) cone-beam computed tomography (CBCT) projections versus single energy (SE) CBCT projections. Methods: A RANDO chest phantom with a simulated tumor in the upper right lung was used to investigate the effectiveness of tumor tracking using DE and SE CBCT projections. Planar kV projections from CBCT acquisitions were captured at 60 kVp (4 mAs) and 120 kVp (1 mAs) using the Varian TrueBeam and non-commercial iTools Capture software. Projections were taken at approximately every 0.53° while the gantry rotated. Due to limitations of the phantom, angles for which the shoulders blocked the tumor were excluded from tracking analysis. DE images were constructed using a weighted logarithmic subtraction that removed bony anatomy while preserving soft tissue structures. The tumors were tracked separately on DE and SE (120 kVp) images using a template-based tracking algorithm. The tracking results were compared to ground truth coordinates designated by a physician. Matches with a distance of greater than 3 mm from ground truth were designated as failing to track. Results: 363 frames were analyzed. The algorithm successfully tracked the tumor on 89.8% (326/363) of DE frames compared to 54.3% (197/363) of SE frames (p<0.0001). Average distance between tracking and ground truth coordinates was 1.27 +/− 0.67 mm for DE versus 1.83+/−0.74 mm for SE (p<0.0001). Conclusion: This study demonstrates the effectiveness of markerless template-based tracking using DE CBCT. DE imaging resulted in better detectability with more accurate localization on average versus SE. Supported by a grant from Varian Medical Systems

  6. Analysis on the Effect of Sensor Views in Image Reconstruction Produced by Optical Tomography System Using Charge-Coupled Device.

    Science.gov (United States)

    Jamaludin, Juliza; Rahim, Ruzairi Abdul; Fazul Rahiman, Mohd Hafiz; Mohd Rohani, Jemmy

    2018-04-01

    Optical tomography (OPT) is a method to capture a cross-sectional image based on the data obtained by sensors, distributed around the periphery of the analyzed system. This system is based on the measurement of the final light attenuation or absorption of radiation after crossing the measured objects. The number of sensor views will affect the results of image reconstruction, where the high number of sensor views per projection will give a high image quality. This research presents an application of charge-coupled device linear sensor and laser diode in an OPT system. Experiments in detecting solid and transparent objects in crystal clear water were conducted. Two numbers of sensors views, 160 and 320 views are evaluated in this research in reconstructing the images. The image reconstruction algorithms used were filtered images of linear back projection algorithms. Analysis on comparing the simulation and experiments image results shows that, with 320 image views giving less area error than 160 views. This suggests that high image view resulted in the high resolution of image reconstruction.

  7. CiOpt: a program for optimization of the frequency response of linear circuits

    OpenAIRE

    Miró Sans, Joan Maria; Palà Schönwälder, Pere

    1991-01-01

    An interactive personal-computer program for optimizing the frequency response of linear lumped circuits (CiOpt) is presented. CiOpt has proved to be an efficient tool in improving designs where the inclusion of more accurate device models distorts the desired frequency response, as well as in device modeling. The outputs of CiOpt are the element values which best match the obtained and the desired frequency response. The optimization algorithms used (the Fletcher-Powell and Newton's methods,...

  8. Tomographic image via background subtraction using an x-ray projection image and a priori computed tomography

    International Nuclear Information System (INIS)

    Zhang Jin; Yi Byongyong; Lasio, Giovanni; Suntharalingam, Mohan; Yu, Cedric

    2009-01-01

    Kilovoltage x-ray projection images (kV images for brevity) are increasingly available in image guided radiotherapy (IGRT) for patient positioning. These images are two-dimensional (2D) projections of a three-dimensional (3D) object along the x-ray beam direction. Projecting a 3D object onto a plane may lead to ambiguities in the identification of anatomical structures and to poor contrast in kV images. Therefore, the use of kV images in IGRT is mainly limited to bony landmark alignments. This work proposes a novel subtraction technique that isolates a slice of interest (SOI) from a kV image with the assistance of a priori information from a previous CT scan. The method separates structural information within a preselected SOI by suppressing contributions to the unprocessed projection from out-of-SOI-plane structures. Up to a five-fold increase in the contrast-to-noise ratios (CNRs) was observed in selected regions of the isolated SOI, when compared to the original unprocessed kV image. The tomographic image via background subtraction (TIBS) technique aims to provide a quick snapshot of the slice of interest with greatly enhanced image contrast over conventional kV x-ray projections for fast and accurate image guidance of radiation therapy. With further refinements, TIBS could, in principle, provide real-time tumor localization using gantry-mounted x-ray imaging systems without the need for implanted markers.

  9. Iron deficiency regulated OsOPT7 is essential for iron homeostasis in rice.

    Science.gov (United States)

    Bashir, Khurram; Ishimaru, Yasuhiro; Itai, Reiko Nakanishi; Senoura, Takeshi; Takahashi, Michiko; An, Gynheung; Oikawa, Takaya; Ueda, Minoru; Sato, Aiko; Uozumi, Nobuyuki; Nakanishi, Hiromi; Nishizawa, Naoko K

    2015-05-01

    The molecular mechanism of iron (Fe) uptake and transport in plants are well-characterized; however, many components of Fe homeostasis remain unclear. We cloned iron-deficiency-regulated oligopeptide transporter 7 (OsOPT7) from rice. OsOPT7 localized to the plasma membrane and did not transport Fe(III)-DMA or Fe(II)-NA and GSH in Xenopus laevis oocytes. Furthermore OsOPT7 did not complement the growth of yeast fet3fet4 mutant. OsOPT7 was specifically upregulated in response to Fe-deficiency. Promoter GUS analysis revealed that OsOPT7 expresses in root tips, root vascular tissue and shoots as well as during seed development. Microarray analysis of OsOPT7 knockout 1 (opt7-1) revealed the upregulation of Fe-deficiency-responsive genes in plants grown under Fe-sufficient conditions, despite the high Fe and ferritin concentrations in shoot tissue indicating that Fe may not be available for physiological functions. Plants overexpressing OsOPT7 do not exhibit any phenotype and do not accumulate more Fe compared to wild type plants. These results indicate that OsOPT7 may be involved in Fe transport in rice.

  10. Assessment of jawbone trabecular bone structure amongst osteoporotic women by cone-beam computed tomography: the OSTEOSYR project.

    Science.gov (United States)

    Barngkgei, Imad; Al Haffar, Iyad; Shaarani, Eyad; Khattab, Razan; Mashlah, Ammar

    2016-11-01

    To assess the trabecular bone structure of jawbones and the dens (the odontoid process of the second cervical vertebra) amongst osteoporotic and nonosteoporotic women using cone-beam computed tomography (CBCT). Analysis of the dens trabecular bone structure aimed to test the validity of CBCT in such analysis. Thirty-eight women who went under dual-energy X-ray absorptiometry (DXA) examination were scanned by CBCT. Cuboids from different areas of jawbones and the dens were extracted from each scan. Trabecular thickness (Tb.Th), trabecular separation (Tb.S), bone volume fraction (BV/TV), specific bone surface (BS/TV) and connectivity density were calculated. Student's t-test, Pearson correlation, and logistic regression analysis were used to explore differences in these measures between groups. Jawbone-derived measures showed insignificant differences (P > 0.05) between osteoporotic and non-osteoporotic groups, and weak correlations with femoral neck and lumbar vertebrae T-scores (r ≤ 0.4). Dens-derived measures, however, resulted in the opposite (r = 0.34-0.38 [P value = 0.02-0.036] and r = 0.48-0.61 [P value ≤ 0.003]) and the highest accuracy of osteoporosis prediction: 84.2% and 78.9% respectively. Trabecular bone structure of the mandible and maxilla is not affected in osteoporosis as assessed by CBCT. Dens trabecular bone analysis revealed the opposite, so some trabecular bone measures may be assessed by CBCT, which may aid in predicting osteoporosis. © 2015 Wiley Publishing Asia Pty Ltd.

  11. Opt-out as an acceptable method of obtaining consent in medical research: a short report.

    LENUS (Irish Health Repository)

    Vellinga, Akke

    2011-04-06

    Abstract Background A prospective cohort study was set up to investigate a possible association between antibiotic prescribing and antibiotic resistance of E. coli urinary tract infection in the community. Participation of patients with urinary tract infection was obtained through an opt-out methodology. This short paper reports on the acceptability of the opt-out recruitment approach. Methods Participating practices (22) were requested to send a urine sample from all patients presenting with symptoms of urinary tract infection. Upon receipt of the sample in the laboratory, a letter explaining the study, an opt-out form and a freepost envelope were sent to all adult patients. A website with additional information and including an \\'opt-out\\' button was set up for the study. Results A total of 1362 urine samples were submitted by the 22 participating practices representing 1178 adult patients of whom 193 actively responded to the letter: 142 opted out by letter, 15 through the website, 2 by phone and 12 sent the letter back without indication, making a total of 171 patients or 14.5% opt-out; the remaining 22 patients (1.9%) explicitly opted in. The total group consisted of 80% women and the mean age was 50.9 years (sd 20.8). No significant differences were found between patients who participated and those who opted out in terms of age, gender or whether the urine sample was positive or not. Conclusions Overall the opt-out method was well received and participation in the study reached 85.5%. The low number of complaints (2) indicates that this is a generally acceptable method of patient recruitment. The 14.5% opt-out shows that it effectively empowers patients to decline participation. The similarity between patients opting out and the rest of the patients is reassuring for extrapolation of the results of the study.

  12. Uptake of voluntary counselling and testing among young people participating in an HIV prevention trial: comparison of opt-out and opt-in strategies.

    Directory of Open Access Journals (Sweden)

    Kathy Baisley

    Full Text Available HIV voluntary counselling and testing (VCT is an integral component of HIV prevention and treatment programmes. However, testing coverage in sub-Saharan Africa is still low, particularly among young people. As treatment becomes more widely available, strategies to expand VCT coverage are critically important. We compare VCT uptake using two delivery strategies (opt-in and opt-out within the MEMA kwa Vijana trial in 20 communities in northwest Tanzania.We analysed data from 12,590 young persons (median (IQR age 22 years (20-23 to assess the effect of delivery strategy on VCT uptake. Ten communities used an opt-in approach and 10 used opt-out, balanced across intervention and control. Conditional logistic regression was used to examine factors associated with uptake within each strategy.VCT uptake was significantly higher with the opt-out approach (90.9% vs 60.5%, prevalence ratio = 1.51, CI = 1.41-1.62. Among females, uptake in the opt-out approach was associated with decreased knowledge of HIV acquisition, sex with a casual partner, and being HSV-2 seronegative; among males, uptake was associated with lower education and increasing lifetime partners. In contrast, uptake using the opt-in approach varied by ethnic group, religion and marital status, and increased with increasing knowledge of STI acquisition (males or pregnancy prevention (females.VCT uptake among young people was extremely high when offered an opt-out strategy. Sociodemographic and knowledge factors affected uptake in different ways depending on delivery strategy. Increased knowledge may increase young persons' self-efficacy, which may have a different impact on testing uptake, depending on the approach used.

  13. Computerized tomography

    International Nuclear Information System (INIS)

    Rubashov, I.B.

    1985-01-01

    Operating principle is described for the devices of computerized tomography used in medicine for diagnosis of brain diseases. Computerized tomography is considered as a part of computerized diagnosis, as a part of information science. It is shown that computerized tomography is a real existed field of investigations in medicine and industrial production

  14. Opt-Out Parental Consent in Online Surveys: Ethical Considerations.

    Science.gov (United States)

    Harris, Jane; Porcellato, Lorna

    2018-07-01

    This article aims to foster discussion and debate around seeking parental consent from young people recruited online. The growth of social media, particularly for young people, has led to increased interest in young people's online activities as both a research topic and recruitment setting. In a health-related study, which sought to recruit young people aged 13 to 18 years old from YouTuber fan communities to an online survey, the question arose of how parental consent could be sought from young people below 16 when no link existed between researcher and parents/guardians. A practical strategy is proposed which combines novel communication methods for participant information, opt-out online consent and age verification to address this issue. Strengths and limitations of these approaches are discussed.

  15. General k-opt submoves for the Lin-Kernighan TSP heuristic

    DEFF Research Database (Denmark)

    Helsgaun, Keld

    2009-01-01

    Local search with k-exchange neighborhoods, k-opt, is the most widely used heuristic method for the traveling salesman problem (TSP). This paper presents an effective implementation of k-opt in LKH-2, a variant of the Lin–Kernighan TSP heuristic. The effectiveness of the implementation...

  16. An Effective Implementation of K-opt Moves for the Lin-Kernighan TSP Heuristic

    DEFF Research Database (Denmark)

    Helsgaun, Keld

    Local search with k-change neighborhoods, k-opt, is the most widely used heuristic method for the traveling salesman problem (TSP). This report presents an effective implementation of k-opt for the Lin- Kernighan TSP heuristic. The effectiveness of the implementation is demonstrated with extensive...

  17. Assessing the impact of opt-out definitions in choice experiments

    DEFF Research Database (Denmark)

    Olsen, Søren Bøye; Campbell, Danny; Mørkbak, Morten Raun

    that this heuristic has a larger impact when the opt-out is defined as respondents own typical (perceived) purchase than when defined as a none-of-these or a provided hypothetical alternative. We consequently stress the importance for researchers to be aware of these possible implications related to the definition...... of opt-out alternatives in choice experiments....

  18. 12 CFR 573.15 - Other exceptions to notice and opt out requirements.

    Science.gov (United States)

    2010-01-01

    ... consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out of future... PRIVACY OF CONSUMER FINANCIAL INFORMATION Exceptions § 573.15 Other exceptions to notice and opt out... consumer, provided that the consumer has not revoked the consent or direction; (2)(i) To protect the...

  19. 12 CFR 716.15 - Other exceptions to notice and opt out requirements.

    Science.gov (United States)

    2010-01-01

    ... insurance to the consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out... AFFECTING CREDIT UNIONS PRIVACY OF CONSUMER FINANCIAL INFORMATION Exceptions § 716.15 Other exceptions to... notice to consumers in § 716.4(a)(2), the opt out in §§ 716.7 and 716.10 and service providers and joint...

  20. 17 CFR 248.123 - Contents of opt out notice; consolidated and equivalent notices.

    Science.gov (United States)

    2010-04-01

    ... EXCHANGE COMMISSION (CONTINUED) REGULATIONS S-P AND S-AM Regulation S-AM: Limitations on Affiliate Marketing § 248.123 Contents of opt out notice; consolidated and equivalent notices. (a) Contents of opt out...) The name of the affiliate(s) providing the notice. If the notice is provided jointly by multiple...

  1. 12 CFR 717.21 - Affiliate marketing opt-out and exceptions.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions. 717.21 Section 717.21 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS FAIR CREDIT REPORTING Affiliate Marketing § 717.21 Affiliate marketing opt-out and exceptions. (a...

  2. Legal issues associated with opting out of the use of nuclear power

    International Nuclear Information System (INIS)

    Butzke, K.; Storr, S.

    2000-01-01

    The article is a summary of a conference held at Jena University at which the political issues of opting out of using nuclear power were scrutinized under aspects of (constitutional) law. The results of the conference were summed up in the Jena Theses about Opting out of the use of Nuclear Power. (orig.) [de

  3. 12 CFR 334.21 - Affiliate marketing opt-out and exceptions.

    Science.gov (United States)

    2010-01-01

    ... solicitation for marketing purposes to a consumer with whom you have a pre-existing business relationship; (2... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions. 334... OF GENERAL POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.21 Affiliate marketing opt-out and...

  4. 12 CFR 334.22 - Scope and duration of opt-out.

    Science.gov (United States)

    2010-01-01

    ... POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.22 Scope and duration of opt-out. (a) Scope of opt... relationship—(i) In general. If the consumer establishes a continuing relationship with you or your affiliate... continuing relationship or multiple continuing relationships that the consumer establishes with you or your...

  5. 12 CFR 571.21 - Affiliate marketing opt-out and exceptions.

    Science.gov (United States)

    2010-01-01

    ... solicitation for marketing purposes to a consumer with whom you have a pre-existing business relationship; (2... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions. 571... CREDIT REPORTING Affiliate Marketing § 571.21 Affiliate marketing opt-out and exceptions. (a) Initial...

  6. 12 CFR 717.26 - Delivery of opt-out notices.

    Science.gov (United States)

    2010-01-01

    ... CREDIT REPORTING Affiliate Marketing § 717.26 Delivery of opt-out notices. (a) In general. The opt-out... the notice; or (4) Posts the notice on the Internet Web site at which the consumer obtained a product... notice; or (3) Posts the notice on an Internet Web site without requiring the consumer to acknowledge...

  7. 12 CFR 41.26 - Delivery of opt-out notices.

    Science.gov (United States)

    2010-01-01

    ... Affiliate Marketing § 41.26 Delivery of opt-out notices. (a) In general. The opt-out notice must be provided... the notice on the Internet Web site at which the consumer obtained a product or service electronically... on an Internet Web site without requiring the consumer to acknowledge receipt of the notice. ...

  8. 12 CFR 334.25 - Reasonable and simple methods of opting out.

    Science.gov (United States)

    2010-01-01

    ... STATEMENTS OF GENERAL POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.25 Reasonable and simple methods... or processed at an Internet Web site, if the consumer agrees to the electronic delivery of... opt-out under the Act, and the affiliate marketing opt-out under the Act, by a single method, such as...

  9. 12 CFR 571.26 - Delivery of opt-out notices.

    Science.gov (United States)

    2010-01-01

    ... Affiliate Marketing § 571.26 Delivery of opt-out notices. (a) In general. The opt-out notice must be... the notice on the Internet Web site at which the consumer obtained a product or service electronically... on an Internet Web site without requiring the consumer to acknowledge receipt of the notice. ...

  10. 12 CFR 222.25 - Reasonable and simple methods of opting out.

    Science.gov (United States)

    2010-01-01

    ... FEDERAL RESERVE SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.25 Reasonable and... electronically mailed or processed at an Internet Web site, if the consumer agrees to the electronic delivery of... opt-out under the Act, and the affiliate marketing opt-out under the Act, by a single method, such as...

  11. Digital multilayer tomography

    International Nuclear Information System (INIS)

    Dueber, C.; Klose, K.J.; Thelen, M.

    1991-01-01

    With digital multilayer tomography a sequence of projection images is recorded by an image intensifier television system and stored as digital data during a linear run of a layer sequence. Using this data record, tomograms of the examined body region can be computed for any layer thickness by shifts and superimposition of the single projections later at a digital workstation. The qualities of digital and conventional tomograms are basically comparable. A drawback of digital tomography is its lower local resolution (512 x 512 image matrix), advantages are a lower radiation exposure, a shorter patient examination time, and the facilities of digital image processing (later processing, archive setup, transmission). (orig.) [de

  12. Opt-out screening strategy for HIV infection among patients attending emergency departments: systematic review and meta-analysis.

    Science.gov (United States)

    Henriquez-Camacho, C; Villafuerte-Gutierrez, P; Pérez-Molina, J A; Losa, J; Gotuzzo, E; Cheyne, N

    2017-07-01

    International health agencies have promoted nontargeted universal (opt-out) HIV screening tests in different settings, including emergency departments (EDs). We performed a systematic review and meta-analysis to assess the testing uptake of strategies (opt-in targeted, opt-in nontargeted and opt-out) to detect new cases of HIV infection in EDs. We searched the Pubmed and Embase databases, from 1984 to April 2015, for opt-in and opt-out HIV diagnostic strategies used in EDs. Randomized controlled or quasi experimental studies were included. We assessed the percentage of positive individuals tested for HIV infection in each programme (opt-in and opt-out strategies). The mean percentage was estimated by combining studies in a random-effect meta-analysis. The percentages of individuals tested in the programmes were compared in a random-effect meta-regression model. Data were analysed using stata version 12. Quality assessments were performed using the Newcastle-Ottawa Scale. Of the 90 papers identified, 28 were eligible for inclusion. Eight trials used opt-out, 18 trials used opt-in, and two trials used both to detect new cases of HIV infection. The test was accepted and taken by 75 155 of 172 237 patients (44%) in the opt-out strategy, and 73 581 of 382 992 patients (19%) in the opt-in strategy. The prevalence of HIV infection detected by the opt-out strategy was 0.40% (373 cases), that detected by the opt-in nontargeted strategy was 0.52% (419 cases), and that detected by the opt-in targeted strategy was 1.06% (52 cases). In this meta-analysis, the testing uptake of the opt-out strategy was not different from that of the opt-in strategy to detect new cases of HIV infection in EDs. © 2016 British HIV Association.

  13. Computer tomography of the neurocranium.

    Science.gov (United States)

    Liliequist, B; Forssell, A

    1976-07-01

    The experience with computer tomography of the neurocranium in 300 patients submitted for computer tomography of the brain is reported. The more appropriate projections which may be obtained with the second generation of scanners in combination with an elaborated reconstruction technique seem to constitute a replacement of conventional skull films.

  14. Optical projection tomography reveals dynamics of HEV growth after immunization with protein plus CFA and features shared with HEVs in acute autoinflammatory lymphadenopathy.

    Science.gov (United States)

    Kumar, Varsha; Chyou, Susan; Stein, Jens V; Lu, Theresa T

    2012-01-01

    The vascular-stromal compartment of lymph nodes is important for lymph node function, and high endothelial venules (HEVs) play a critical role in controlling the entry of recirculating lymphocytes. In autoimmune and autoinflammatory diseases, lymph node swelling is often accompanied by apparent HEV expansion and, potentially, targeting HEV expansion could be used therapeutically to limit autoimmunity. In previous studies using mostly flow cytometry analysis, we defined three differentially regulated phases of lymph node vascular-stromal growth: initiation, expansion, and the re-establishment of vascular quiescence and stabilization. In this study, we use optical projection tomography to better understand the morphologic aspects of HEV growth upon immunization with ovalbumin/CFA (OVA/CFA). We find HEV elongation as well as modest arborization during the initiation phase, increased arborization during the expansion phase, and, finally, vessel narrowing during the re-establishment of vascular quiescence and stabilization. We also examine acutely enlarged autoinflammatory lymph nodes induced by regulatory T cell depletion and show that HEVs are expanded and morphologically similar to the expanded HEVs in OVA/CFA-stimulated lymph nodes. These results reinforce the idea of differentially regulated, distinct phases of vascular-stromal growth after immunization and suggest that insights gained from studying immunization-induced lymph node vascular growth may help to understand how the lymph node vascular-stromal compartment could be therapeutically targeted in autoimmune and autoinflammatory diseases.

  15. Optical projection tomography reveals dynamics of HEV growth after immunization with protein plus CFA and features shared with HEVs in acute autoinflammatory lymphadenopathy

    Directory of Open Access Journals (Sweden)

    Varsha eKumar

    2012-09-01

    Full Text Available The vascular-stromal compartment of lymph nodes is important for lymph node function, and high endothelial venules (HEVs play a critical role in controlling the entry of recirculating lymphocytes. In autoimmune and autoinflammatory diseases, lymph node swelling is often accompanied by apparent HEV expansion and, potentially, targeting HEV expansion could be used therapeutically to limit autoimmunity. In previous studies using mostly flow cytometry analysis, we defined 3 differentially regulated phases of lymph node vascular-stromal growth: initiation, expansion, and the re-establishment of vascular quiescence and stabilization. In this study, we use optical projection tomography to better understand the morphologic aspects of HEV growth upon immunization with ovalbumin/CFA. We find HEV elongation as well as modest arborization during the initiation phase, increased arborization during the expansion phase, and, finally, vessel narrowing during the re-establishment of vascular quiescence and stabilization. We also examine acutely enlarged autoinflammatory lymph nodes induced by regulatory T cell depletion and show that HEVs are expanded and morphologically similar to the expanded HEVs in OVA/CFA-stimulated lymph nodes. These results reinforce the idea of differentially regulated, distinct phases of vascular-stromal growth after immunization and suggest that insights gained from studying immunization-induced lymph node vascular growth may help to understand how the lymph node vascular-stromal compartment could be therapeutically targeted in autoimmune and autoinflammatory diseases.

  16. Local detection of prostate cancer by positron emission tomography with 2-fluorodeoxyglucose comparison of filtered back projection and iterative reconstruction with segmented attenuation correction

    International Nuclear Information System (INIS)

    Turlakow, A.; Larson, S. M.; Coakley, F.; Akhurst, T.; Macapinlac, H. A.; Hricak, H.; Gonen, M.; Kelly, W.; Scher, H.; Leibel, S.; Humm, J.; Scardino, P.

    2001-01-01

    To compare filtered back projection (FBP) and iterative reconstruction with segmented attenuation correction (IRSAC) in the local imaging of prostate cancer by positron emission tomography with 2-fluorodeoxyglucose (FDG-PET). 13 patients with primary (n=7) or recurrent (n=6) prostate cancer who had increased uptake in the prostate on FDG-PET performed without urinary catheterization, contemporaneous biopsy confirming the presence of active tumor in the prostate, were retrospectively identified. Two independent nuclear medicine physicians separately rated FBP and IRSAC images for visualization of prostatic activity on a 4-point scale. Results were compared using biopsy and cross-sectional imaging findings as the standard of reference. IRSAC images were significantly better that FBP in terms of visualization of prostatic activity in 12 of 13 patients, and were equivalent in 1 patient (p<0.001, Wilcoxon signed ranks test). In particular, 2 foci of tumor activity in 2 different patients seen on IRSAC images were not visible on FBP images. In 11 patients who had a gross tumor mass evident on cross-sectional imaging, there was good agreement between PET and cross-sectional anatomic imaging with respect to tumor localization. In selected patients, cancer can be imaged within the prostate using FDG-PET, and IRSAC is superior to FBP in image reconstruction for local tumor visualization

  17. On-Line Use of Three-Dimensional Marker Trajectory Estimation From Cone-Beam Computed Tomography Projections for Precise Setup in Radiotherapy for Targets With Respiratory Motion

    International Nuclear Information System (INIS)

    Worm, Esben S.; Høyer, Morten; Fledelius, Walther; Nielsen, Jens E.; Larsen, Lars P.; Poulsen, Per R.

    2012-01-01

    Purpose: To develop and evaluate accurate and objective on-line patient setup based on a novel semiautomatic technique in which three-dimensional marker trajectories were estimated from two-dimensional cone-beam computed tomography (CBCT) projections. Methods and Materials: Seven treatment courses of stereotactic body radiotherapy for liver tumors were delivered in 21 fractions in total to 6 patients by a linear accelerator. Each patient had two to three gold markers implanted close to the tumors. Before treatment, a CBCT scan with approximately 675 two-dimensional projections was acquired during a full gantry rotation. The marker positions were segmented in each projection. From this, the three-dimensional marker trajectories were estimated using a probability based method. The required couch shifts for patient setup were calculated from the mean marker positions along the trajectories. A motion phantom moving with known tumor trajectories was used to examine the accuracy of the method. Trajectory-based setup was retrospectively used off-line for the first five treatment courses (15 fractions) and on-line for the last two treatment courses (6 fractions). Automatic marker segmentation was compared with manual segmentation. The trajectory-based setup was compared with setup based on conventional CBCT guidance on the markers (first 15 fractions). Results: Phantom measurements showed that trajectory-based estimation of the mean marker position was accurate within 0.3 mm. The on-line trajectory-based patient setup was performed within approximately 5 minutes. The automatic marker segmentation agreed with manual segmentation within 0.36 ± 0.50 pixels (mean ± SD; pixel size, 0.26 mm in isocenter). The accuracy of conventional volumetric CBCT guidance was compromised by motion smearing (≤21 mm) that induced an absolute three-dimensional setup error of 1.6 ± 0.9 mm (maximum, 3.2) relative to trajectory-based setup. Conclusions: The first on-line clinical use of

  18. The OptIC Data Assimilation Intercomparison: A Statistical Critique

    Science.gov (United States)

    Enting, I. G.; Clisby, N.

    2008-12-01

    The development of improved terrestrial carbon models has assumed great importance because of concerns about significant climate-to-carbon feedback processes. The complexity of the interactions leads to considerable difficulties in the process of model calibration. The OptIC intercomparison explored some aspects of model calibration, using an idealised terrestrial carbon model. Participants were invited to estimate model parameters in various cases defined by specified time series of the model state, with various forms of added noise. The study identified the crucial importance of the choice of cost function. The present analysis revisits the OptIC study, by considering it as an exercise in statistical estimation. This treats the observations as random variables. Consequently parameter estimates, â, based on observations will also be random variables whose distribution is known as the 'sampling distribution'. Key questions for any specific case are: Are departures from â/a_true =1 indication of bias or sampling error? Under what circumstance are uncertainty estimates (of Var[â]) reliable? We consider cases where the estimate is obtained by minimising a cost function, ΘX. Assuming that we know the true form of ℓ, the log likelihood, there are three different characterisations of uncertainty that should be distinguished: (i) The uncertainty from maximum-likelihood estimates, corresponding (either exactly or asymptotically) to the Cramer-Rao bound. In a realistic calibration situation, we won't be able to determine this because the 'true' form of the likelihood is unknown. (ii) The actual uncertainty associated with using a particular cost function. If the true noise distribution is known, this can be calculated in simple cases and determined from simulations in more complicated cases. (iii) The 'formal uncertainty' based on assuming (usually incorrectly) that ΘX is the true likelihood. In the first stage of the analysis, the distinctions are illustrated by

  19. Geophysical Investigation using Two Dimensional Electrical Resistivity Tomography method to delineate Subsurface Geological Structures at Dudhkoshi-II (230 MW) Hydroelectric Project, Solukhumbu District, Eastern Nepal

    Science.gov (United States)

    Ghimire, H.; Bhusal, U. C.; Khatiwada, B.; Pandey, D.

    2017-12-01

    Geophysical investigation using two dimensional electrical resistivity tomography (2D-ERT) method plays a significant role in determining the subsurface resistivity distribution by making measurement on the ground surface. This method was carried out at Dudhkoshi-II (230 MW) Hydroelectric Project, lies on Lesser Himalayan region of the Eastern Nepal to delineate the nature of the subsurface geology to assess its suitability for the construction of dam, desanding basin and powerhouse. The main objective of the proposed study consists of mapping vertical as well as horizontal variations of electrical resistivity to enable detection of the boundaries between unconsolidated materials and rocks of the different resistivity, possible geologic structures, such as possible presence of faults, fractures, and voids in intake and powerhouse area. For this purpose, the (WDJD-4 Multi-function Digital DC Resistivity/IP) equipment was used with Wenner array (60 electrodes). To fulfill these objectives of the study, the site area was mapped by Nine ERT profiles with different profile length and space between electrodes was 5 m. The depth of the investigation was 50 m. The acquired data were inverted to tomogram sections using tomographic inversion with RES2DINV commercial software. The Tomography sections show that the subsurface is classified into distinct geo-electric layers of dry unconsolidated overburden, saturated overburden, fractured rock and fresh bedrock of phyllites with quartzite and gneiss with different resistivity values. There were no voids and faults in the study area. Thickness of overburden at different region found to be different. Most of the survey area has bedrock of phyllites with quartzite; gneiss is also present in some location at intake area. Bedrock is found at the varies depth of 5-8 m at dam axis, 20-32 m at desanding basin and 3-10 m at powerhouse area. These results are confirmed and verified by using several boreholes data were drilled on the

  20. The OptD-multi method in LiDAR processing

    International Nuclear Information System (INIS)

    Błaszczak-Bąk, Wioleta; Sobieraj-Żłobińska, Anna; Kowalik, Michał

    2017-01-01

    New and constantly developing technology for acquiring spatial data, such as LiDAR (light detection and ranging), is a source for large volume of data. However, such amount of data is not always needed for developing the most popular LiDAR products: digital terrain model (DTM) or digital surface model. Therefore, in many cases, the number of contained points are reduced in the pre-processing stage. The degree of reduction is determined by the algorithm used, which should enable the user to obtain a dataset appropriate and optimal for the planned purpose. The aim of this article is to propose a new Optimum Dataset method (OptD method) in the processing of LiDAR point clouds. The OptD method can reduce the number of points in a dataset for the specified optimization criteria concerning the characteristics of generated DTM. The OptD method can be used in two variants: OptD-single (one criterion for optimization) and OptD-multi (two or more optimization criteria). The OptD-single method has been thoroughly tested and presented by Błaszczak-Bąk (2016 Acta Geodyn. Geomater . 13/4 379–86). In this paper the authors discussed the OptD-multi method. (paper)

  1. Positron emission tomography

    International Nuclear Information System (INIS)

    Pavuk, M.

    2003-12-01

    The aim of this project is to provide a simple summary of new trends in positron emission tomography and its basic physical principles. It provides thereby compendious introduction of the trends of the present development in diagnostics using PET systems. A review of available literature was performed. (author)

  2. On uniqueness in diffuse optical tomography

    International Nuclear Information System (INIS)

    Harrach, Bastian

    2009-01-01

    A prominent result of Arridge and Lionheart (1998 Opt. Lett. 23 882–4) demonstrates that it is in general not possible to simultaneously recover both the diffusion (aka scattering) and the absorption coefficient in steady-state (dc) diffusion-based optical tomography. In this work we show that it suffices to restrict ourselves to piecewise constant diffusion and piecewise analytic absorption coefficients to regain uniqueness. Under this condition both parameters can simultaneously be determined from complete measurement data on an arbitrarily small part of the boundary

  3. Deemed consent: Assessing the new opt-out approach to organ procurement in Wales

    DEFF Research Database (Denmark)

    Albertsen, Andreas

    2018-01-01

    In December 2015, Wales became the first country in the UK to move away from an opt-in system in organ procurement. The new legislation introduces the concept of deemed consent whereby a person who neither opt in nor opt out is deemed to have consented to donation. The data released by the National...... Health Service (NHS) in July 2017 provide an excellent opportunity to assess this legislation in light of concerns that it would decrease procurement rates for living and deceased donation, as well as sparking an increase in family refusals. None of these concerns have come to pass, with Wales...

  4. Objective Provision Tree (OPT) in sodium cooled fast reactors; Objective Provision Tree (OPT) en reactores rapidos refrigerados por sodio. Aplicacion a la funcion de seguridad de evacuacion de calor residual

    Energy Technology Data Exchange (ETDEWEB)

    Queral, C.; Montero-Mayorga, J.; Gonzalez-Cadelo, J.

    2013-07-01

    Application to the safety function of residual heat removal As part of the project {sup S}afety Assessment for Reactor of GEN-IV (SARGEN IV) has been implemented the methodology ISAM from the IAEA to the safety assessment of new sodium reactor designs. Within the ISAM, a new tool to facilitate this assessment is the Objective Provision Tree (OPT) which documents the provisions necessary for each of the levels of defense in depth, as well as for each critical function of security. Due to the design innovations that have sodium reactors, the evaluation of safety and licensing of these reactors requires special considerations. In this work we have analyzed the mechanisms of failure of the safety function concerning the evacuation of waste heat, and have been proposed different provisions for each of the first three levels of defense in depth. The main result of this work is reflected in the elaboration of the OPTs, one for each of the first three levels of defense in depth for the safety of evacuation of residual heat function. These trees represent in a schematic way the provisions necessary to comply with the objectives of each level which are respectively: 1) deviations from normal operation, 2) control of abnormal operation and fault detection and 3) incidental control.

  5. Optimization of the radiological protection of patients undergoing radiography, fluoroscopy and computed tomography. Final report of a coordinated research project in Africa, Asia and eastern Europe

    International Nuclear Information System (INIS)

    2004-12-01

    Although radiography has been an established imaging modality for over a century, continuous developments have led to improvements in technique resulting in improved image quality at reduced patient dose. If one compares the technique used by Roentgen with the methods used today, one finds that a radiograph can now be obtained at a dose which is smaller by a factor of 100 or more. Nonetheless, some national surveys, particularly in the United Kingdom and in the United States of America in the 1980s and 1990s, have indicated large variations in patient doses for the same diagnostic examination, in some cases by a factor of 20 or more. This arises not only owing to the various types of equipment and accessories used by the different health care providers, but also because of operational factors. The IAEA has a statutory responsibility to establish standards for the protection of people against exposure to ionising radiation and to provide for the worldwide application of those standards. A fundamental requirement of the International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS), issued by the IAEA in cooperation with the FAO, ILO, WHO, PAHO and NEA, is the optimization of radiological protection of patients undergoing medical exposure. Towards its responsibility of implementation of standards and under the subprogramme of radiation safety, in 1995, the IAEA launched a coordinated research project (CRP) on radiological protection in diagnostic radiology in some countries in the Eastern European, African and Asian region. Initially, the CRP addressed radiography only and it covered wide aspects of optimisation of radiological protection. Subsequently, the scope of the CRP was extended to fluoroscopy and computed tomography (CT), but it covered primarily situation analysis of patient doses and equipment quality control. It did not cover patient dose reduction aspects in fluoroscopy and CT. The project

  6. Optical Tomography in Combustion

    DEFF Research Database (Denmark)

    Evseev, Vadim

    spectral measurements at several line-of-sights with a view to applications for tomographic measurements on full-scale industrial combustion systems. The system was successfully applied on industrial scale for simultaneous fast exhaust gas temperature measurements in the three optical ports of the exhaust......D project, it was also important to investigate the spectral properties of major combustion species such as carbon dioxide and carbon monoxide in the infrared range at high temperatures to provide the theoretical background for the development of the optical tomography methods. The new software....... JQSRT 113 (2012) 2222, 10.1016/j.jqsrt.2012.07.015] included in the PhD thesis as an attachment. The knowledge and experience gained in the PhD project is the first important step towards introducing the advanced optical tomography methods of combustion diagnostics developed in the project to future...

  7. Projectables

    DEFF Research Database (Denmark)

    Rasmussen, Troels A.; Merritt, Timothy R.

    2017-01-01

    CNC cutting machines have become essential tools for designers and architects enabling rapid prototyping, model-building and production of high quality components. Designers often cut from new materials, discarding the irregularly shaped remains. We introduce ProjecTables, a visual augmented...... reality system for interactive packing of model parts onto sheet materials. ProjecTables enables designers to (re)use scrap materials for CNC cutting that would have been previously thrown away, at the same time supporting aesthetic choices related to wood grain, avoiding surface blemishes, and other...... relevant material properties. We conducted evaluations of ProjecTables with design students from Aarhus School of Architecture, demonstrating that participants could quickly and easily place and orient model parts reducing material waste. Contextual interviews and ideation sessions led to a deeper...

  8. 4D Electron Tomography

    Science.gov (United States)

    Kwon, Oh-Hoon; Zewail, Ahmed H.

    2010-06-01

    Electron tomography provides three-dimensional (3D) imaging of noncrystalline and crystalline equilibrium structures, as well as elemental volume composition, of materials and biological specimens, including those of viruses and cells. We report the development of 4D electron tomography by integrating the fourth dimension (time resolution) with the 3D spatial resolution obtained from a complete tilt series of 2D projections of an object. The different time frames of tomograms constitute a movie of the object in motion, thus enabling studies of nonequilibrium structures and transient processes. The method was demonstrated using carbon nanotubes of a bracelet-like ring structure for which 4D tomograms display different modes of motion, such as breathing and wiggling, with resonance frequencies up to 30 megahertz. Applications can now make use of the full space-time range with the nanometer-femtosecond resolution of ultrafast electron tomography.

  9. Multidetector computed tomography of the head in acute stroke: predictive value of different patterns of the dense artery sign revealed by maximum intensity projection reformations for location and extent of the infarcted area

    Energy Technology Data Exchange (ETDEWEB)

    Gadda, Davide; Vannucchi, Letizia; Niccolai, Franco; Neri, Anna T.; Carmignani, Luca; Pacini, Patrizio [Ospedale del Ceppo, U.O. Radiodiagnostica, Pistoia (Italy)

    2005-12-01

    Maximum intensity projections reconstructions from 2.5 mm unenhanced multidetector computed tomography axial slices were obtained from 49 patients within the first 6 h of anterior-circulation cerebral strokes to identify different patterns of the dense artery sign and their prognostic implications for location and extent of the infarcted areas. The dense artery sign was found in 67.3% of cases. Increased density of the whole M1 segment with extension to M2 of the middle cerebral artery was associated with a wider extension of cerebral infarcts in comparison to M1 segment alone or distal M1 and M2. A dense sylvian branch of the middle cerebral artery pattern was associated with a more restricted extension of infarct territory. We found 62.5% of patients without a demonstrable dense artery to have a limited peripheral cortical or capsulonuclear lesion. In patients with a 7-10 points on the Alberta Stroke Early Programme Computed Tomography Score and a dense proximal MCA in the first hours of ictus the mean decrease in the score between baseline and follow-up was 5.09{+-}1.92 points. In conclusion, maximum intensity projections from thin-slice images can be quickly obtained from standard computed tomography datasets using a multidetector scanner and are useful in identifying and correctly localizing the dense artery sign, with prognostic implications for the entity of cerebral damage. (orig.)

  10. Rethinking HIV exceptionalism: the ethics of opt-out HIV testing in sub-Saharan Africa

    Science.gov (United States)

    2010-01-01

    Abstract Opt-out testing for the human immunodeficiency virus (HIV) incorporates testing as a routine part of health care for all patients unless they refuse. The ethics of this approach to testing in sub-Saharan Africa is a source of controversy. Opt-out HIV testing is expected to improve survival by increasing case detection and thus linking more HIV-infected people to earlier treatment, provided there is effective patient follow-up and programme sustainability. At the population level, these benefits will likely outweigh the potential negative consequences of individuals experiencing HIV-related stigma. These justifications appeal to consequentialist moral theories that the acceptability of an action depends upon its outcomes. On the other hand, liberal moral theories state that the autonomy of individuals should always be protected unless restricting autonomy is necessary to protect the welfare of others. Opt-out consent may restrict autonomy and it is unclear whether it would benefit people other than those being tested. Yet, the doctrine of libertarian paternalism proposes that it is justifiable and desirable to use unobtrusive mechanisms to help individuals make choices to maximize their own welfare. Central to this idea are the premises featured by supporters of opt-out consent that individuals will not always make the best choices for their own welfare but they may be influenced to do so in ways that will not compromise their freedom of choice. Also important is the premise that all policies inevitably exert some such influence: opt-in consent encourages test refusal just as opt-out consent encourages acceptance. Based on these premises, opt-out testing may be an effective and ethically acceptable policy response to Africa’s HIV epidemic. PMID:20865076

  11. Rethinking HIV exceptionalism: the ethics of opt-out HIV testing in sub-Saharan Africa.

    Science.gov (United States)

    April, Michael D

    2010-09-01

    Opt-out testing for the human immunodeficiency virus (HIV) incorporates testing as a routine part of health care for all patients unless they refuse. The ethics of this approach to testing in sub-Saharan Africa is a source of controversy. Opt-out HIV testing is expected to improve survival by increasing case detection and thus linking more HIV-infected people to earlier treatment, provided there is effective patient follow-up and programme sustainability. At the population level, these benefits will likely outweigh the potential negative consequences of individuals experiencing HIV-related stigma. These justifications appeal to consequentialist moral theories that the acceptability of an action depends upon its outcomes. On the other hand, liberal moral theories state that the autonomy of individuals should always be protected unless restricting autonomy is necessary to protect the welfare of others. Opt-out consent may restrict autonomy and it is unclear whether it would benefit people other than those being tested. Yet, the doctrine of libertarian paternalism proposes that it is justifiable and desirable to use unobtrusive mechanisms to help individuals make choices to maximize their own welfare. Central to this idea are the premises featured by supporters of opt-out consent that individuals will not always make the best choices for their own welfare but they may be influenced to do so in ways that will not compromise their freedom of choice. Also important is the premise that all policies inevitably exert some such influence: opt-in consent encourages test refusal just as opt-out consent encourages acceptance. Based on these premises, opt-out testing may be an effective and ethically acceptable policy response to Africa's HIV epidemic.

  12. Single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Budinger, T.F.

    1986-01-01

    Single photon tomography dates from the early 1960's when the idea of emission transverse section tomography was presented by Kuhl and Edwards. They used a rectilinear scanner and analogue back-projection methods to detect emissions from a series of sequential positions transverse to the cephaldcaudad axis of the body. This chapter presents an explanation of emission tomography by describing longitudinal and transverse section tomography. In principle all modes of tomography can be considered under the general topic of coded apertures wherein the code ranges from translation of a pinhole collimator to rotation of a parallel hole or focused collimator array

  13. OPT13B and OPTIM4 - computer codes for optical model calculations

    International Nuclear Information System (INIS)

    Pal, S.; Srivastava, D.K.; Mukhopadhyay, S.; Ganguly, N.K.

    1975-01-01

    OPT13B is a computer code in FORTRAN for optical model calculations with automatic search. A summary of different formulae used for computation is given. Numerical methods are discussed. The 'search' technique followed to obtain the set of optical model parameters which produce best fit to experimental data in a least-square sense is also discussed. Different subroutines of the program are briefly described. Input-output specifications are given in detail. A modified version of OPT13B specifications are given in detail. A modified version of OPT13B is OPTIM4. It can be used for optical model calculations where the form factors of different parts of the optical potential are known point by point. A brief description of the modifications is given. (author)

  14. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses ... CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed tomography, more commonly known ...

  15. Illustrated computer tomography

    International Nuclear Information System (INIS)

    Takahashi, S.

    1983-01-01

    This book provides the following information: basic aspects of computed tomography; atlas of computed tomography of the normal adult; clinical application of computed tomography; and radiotherapy planning and computed tomography

  16. Why persons choose to opt out of an exception from informed consent cardiac arrest trial.

    Science.gov (United States)

    Nelson, Maria J; Deiorio, Nicole M; Schmidt, Terri A; Zive, Dana M; Griffiths, Denise; Newgard, Craig D

    2013-06-01

    We sought to characterize persons who requested to opt out of an exception from informed consent (EFIC) cardiac arrest trial and their reasons for opting out. At one site of a multi-site, out-of-hospital, cardiac arrest EFIC trial (September 2007 - June 2009), persons who did not want to participate in the study could request an opt-out "NO STUDY" bracelet to prevent trial enrollment. We surveyed all persons who requested a bracelet by phone interview, web or mail. Opt-out bracelets were advertised in all public communication about the study, including community consultation and public disclosure efforts. Survey questions included demographics, Likert scale items about attitudes toward the trial and research in general, plus open-ended questions. We used descriptive statistics for standardized questions and qualitative analysis to identify common themes from open-ended questions. Sixty bracelets were requested by 50 individuals. Surveys were completed by 46 persons (92% response rate). Seventy percent of respondents agreed emergency research is important, but 87% objected to any research without consent. In the qualitative analysis, 5 overlapping themes emerged: questioning the ethics of EFIC research; concerns about how the study would impact end-of-life preferences; subjective emotions including sarcasm, anger, and allusions to past unethical research; negative reference to unrelated public health controversies; and objections to the study protocol based on misinformation. A primary reason for opting out from this EFIC trial was opposition to all research without informed consent, despite stated support for emergency research. Understanding the demographics and beliefs of persons opting out may aid researchers planning EFIC studies and help provide clarity in future EFIC-related community education efforts. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  17. Health-care providers' experiences with opt-out HIV testing: a systematic review.

    Science.gov (United States)

    Leidel, Stacy; Wilson, Sally; McConigley, Ruth; Boldy, Duncan; Girdler, Sonya

    2015-01-01

    HIV is now a manageable chronic disease with a good prognosis, but early detection and referral for treatment are vital. In opt-out HIV testing, patients are informed that they will be tested unless they decline. This qualitative systematic review explored the experiences, attitudes, barriers, and facilitators of opt-out HIV testing from a health-care provider (HCP) perspective. Four articles were included in the synthesis and reported on findings from approximately 70 participants, representing diverse geographical regions and a range of human development status and HIV prevalence. Two synthesized findings emerged: HCP attitudes and systems. The first synthesized finding encompassed HCP decision-making attitudes about who and when to test for HIV. It also included the assumptions the HCPs made about patient consequences. The second synthesized finding related to systems. System-related barriers to opt-out HIV testing included lack of time, resources, and adequate training. System-related facilitators included integration into standard practice, support of the medical setting, and electronic reminders. A common attitude among HCPs was the outdated notion that HIV is a terrible disease that equates to certain death. Some HCPs stated that offering the HIV test implied that the patient had engaged in immoral behaviour, which could lead to stigma or disengagement with health services. This paternalism diminished patient autonomy, because patients who were excluded from opt-out HIV testing could have benefited from it. One study highlighted the positive aspects of opt-out HIV testing, in which participants underscored the professional satisfaction that arose from making an HIV diagnosis, particularly when marginalized patients could be connected to treatment and social services. Recommendations for opt-out HIV testing should be disseminated to HCPs in a broad range of settings. Implementation of system-related factors such as electronic reminders and care coordination

  18. Sacrificio cortoplacista adaptativo 2opt (SCA_2opt: Una heurística inspirada en el pensamiento sistémico

    Directory of Open Access Journals (Sweden)

    Jorge Pérez Rave

    2014-03-01

    Full Text Available Se detalla el origen de dos noveles heurísticas para el TSP simétrico, inspiradas en el pensamiento sistémico: Sacrificio Cortoplacista Adaptativo 2-opt (SCA_2opt y SCA_2_opt_r. Estas surgen del análisis sistémico de la regla de decisión Vecino más cercano, identificándosele el arquetipo "Soluciones contraproducentes". El SCA se basa en que el agente viajero renuncie en un momento dado a una ciudad inmediatamente cercana, y se traslade hacia la segunda ciudad más cercana disponible. A partir de ello, se continúa con la regla del vecino más cercano. Cada que se realiza el SCA (búsqueda global se efectúa una búsqueda local 2_opt. Considerando el binomio eficacia y eficiencia, las dos heurísticas se muestran prometedoras en comparación multicriterio contra 19 metaheurísticas. Se evidencia que el pensamiento sistémico es un campo de inspiración viable para el desarrollo de métodos de optimización combinatoria; se plasman preguntas emergentes para desarrollos futuros, que permitan continuar integrando elementos de la optimización clásica con el pensamiento sistémico; áreas tradicionalmente vistas como antagónicas, pero cuyo diálogo se muestra favorable en este artículo.

  19. Optical tomography of tissues

    International Nuclear Information System (INIS)

    Zimnyakov, D A; Tuchin, Valerii V

    2002-01-01

    Methods of optical tomography of biological tissues are considered, which include pulse-modulation and frequency-modulation tomography, diffusion tomography with the use of cw radiation sources, optical coherent tomography, speckle-correlation tomography of nonstationary media, and optoacoustic tomography. The method for controlling the optical properties of tissues is studied from the point of view of increasing a probing depth in optical coherent tomography. The modern state and prospects of the development of optical tomography are discussed. (review)

  20. Computed tomography

    International Nuclear Information System (INIS)

    Wells, P.; Davis, J.; Morgan, M.

    1994-01-01

    X-ray or gamma-ray transmission computed tomography (CT) is a powerful non-destructive evaluation (NDE) technique that produces two-dimensional cross-sectional images of an object without the need to physically section it. CT is also known by the acronym CAT, for computerised axial tomography. This review article presents a brief historical perspective on CT, its current status and the underlying physics. The mathematical fundamentals of computed tomography are developed for the simplest transmission CT modality. A description of CT scanner instrumentation is provided with an emphasis on radiation sources and systems. Examples of CT images are shown indicating the range of materials that can be scanned and the spatial and contrast resolutions that may be achieved. Attention is also given to the occurrence, interpretation and minimisation of various image artefacts that may arise. A final brief section is devoted to the principles and potential of a range of more recently developed tomographic modalities including diffraction CT, positron emission CT and seismic tomography. 57 refs., 2 tabs., 14 figs

  1. Data transmission optical link for LLRF TESLA project part I: hardware structure of OPT0 module

    Science.gov (United States)

    Pozniak, Krzysztof T.; Romaniuk, Ryszard S.; Jalmuzna, Wojciech; Olowski, Krzysztof; Perkuszewski, Karol; Zielinski, Jerzy; Kierzkowski, Krzysztof

    2006-03-01

    It may be predicted now, even assuming a very conservative approach, that the next generation of the Low Level RF control systems for future accelerators will use extensively such technologies like: very fast programmable circuits equipped with DSP, embedded PC and optical communication I/O functionalities, as well as multi-gigabit optical transmission of measurement data and control signals. The paper presents the idea and realization of a gigabit synchronous data distributor designed to work in the LLRF control system of TESLA technology based X-ray FEL. The design bases on a relatively simple and cheap FPGA chip Cyclone. Commercially available SERDES (serializer/deserializer) and optical transceiver chips were applied. The optoelectronic module is embedded on the main LLRF BMB (backbone mother board). The MB provides communication with the outside computer control system, programmable chip configuration, integration with other functional modules and power supply. The hardware implementation is here described and the used software for BER (bit-error-rate) testing of the multi-gigabit optical link. The measurement results are presented. The appendix contains a comparison between the available protocols of serial data transmission for FPGA technology. This paper is a partial contribution to the next version of the SIMCON system which is expected to be released this year. The SIMCON, ver 3.0 will contain 8 channels and multi-gigabit optical transmission capability. It will be a fully modular construction.

  2. Mathematics of Computed Tomography

    Science.gov (United States)

    Hawkins, William Grant

    A review of the applications of the Radon transform is presented, with emphasis on emission computed tomography and transmission computed tomography. The theory of the 2D and 3D Radon transforms, and the effects of attenuation for emission computed tomography are presented. The algebraic iterative methods, their importance and limitations are reviewed. Analytic solutions of the 2D problem the convolution and frequency filtering methods based on linear shift invariant theory, and the solution of the circular harmonic decomposition by integral transform theory--are reviewed. The relation between the invisible kernels, the inverse circular harmonic transform, and the consistency conditions are demonstrated. The discussion and review are extended to the 3D problem-convolution, frequency filtering, spherical harmonic transform solutions, and consistency conditions. The Cormack algorithm based on reconstruction with Zernike polynomials is reviewed. An analogous algorithm and set of reconstruction polynomials is developed for the spherical harmonic transform. The relations between the consistency conditions, boundary conditions and orthogonal basis functions for the 2D projection harmonics are delineated and extended to the 3D case. The equivalence of the inverse circular harmonic transform, the inverse Radon transform, and the inverse Cormack transform is presented. The use of the number of nodes of a projection harmonic as a filter is discussed. Numerical methods for the efficient implementation of angular harmonic algorithms based on orthogonal functions and stable recursion are presented. The derivation of a lower bound for the signal-to-noise ratio of the Cormack algorithm is derived.

  3. Forum: Making Sense of the Opt-Out Movement: "Education Next" Talks with Scott Levy and Jonah Edelman

    Science.gov (United States)

    Levy, Scott; Edelman, Jonah

    2016-01-01

    Over the past few years, students by the thousands have refused to take their state's standardized tests. This "opt-out" phenomenon has prompted debate in state legislatures and in Washington, putting states at risk of losing Title I funds. Advocates describe opt-out as a grassroots movement of parents concerned about overtesting,…

  4. 'We didn't have to dance around it': opt-out HIV testing among homeless and marginalised patients.

    Science.gov (United States)

    Leidel, Stacy; Leslie, Gavin; Boldy, Duncan; Davies, Andrew; Girdler, Sonya

    2017-07-01

    This study explored opt-out HIV testing in an Australian general practice. The aims were to: (1) determine the effect of the opt-out approach on the number of HIV tests performed; and (2) explore the acceptability of opt-out HIV testing from the healthcare providers' perspective. A prospective mixed-methods study of opt-out HIV testing over a 2-year period (March 2014-March 2016) was conducted. Implementation was based on a theoretical framework that was developed specifically for this study. The setting was Homeless Healthcare, a health service in Perth, Western Australia. The number of HIV tests conducted during the control year (usual practice) was compared with the intervention year (opt-out testing). After the intervention, the healthcare providers (n=8) were interviewed about their experiences with opt-out HIV testing. Directed content analysis was used to explore the qualitative data. HIV testing rates were low during both the control year and the intervention year (315 HIV tests (12% of the patient cohort) and 344 HIV tests (10%) respectively). Opt-out HIV testing was feasible and acceptable to the participating healthcare providers. Other health services could consider opt-out HIV testing for their patients to identify people with undiagnosed infections and sustain Australia's low HIV prevalence.

  5. Methods of X-ray CT image reconstruction from few projections; Methodes de reconstruction d'images a partir d'un faible nombre de projections en tomographie par rayons X

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.

    2011-10-24

    systeme de la tomographie par rayons X (CT), on cherche a reconstruire une image de haute qualite avec un faible nombre de projections. Les algorithmes classiques ne sont pas adaptes a cette situation: la reconstruction est perturbee par artefacts donc instable. Une nouvelle approche basee sur la theorie recente du 'Compressed Sensing' (CS) fait l'hypothese que l'image inconnue est 'parcimonieuse' ou 'compressible', et formule la reconstruction en un probleme d'optimisation (minimisation de la norme TV/l1) afin de promouvoir la parcimonie. Pour appliquer CS en CT avec le pixel (ou le voxel en 3D) comme la base de representation, il necessite une transformation de parcimonie, de plus il faut la combiner avec le 'projecteur du rayon X' qui applique sur une image pixelisee. Dans cette these, on a adapte une base radiale de famille Gaussienne nommee 'blob' a la reconstruction en CT par CS. Le blob a une meilleure localisation spatiofrequentielle que le pixel, et des operations comme la transformee en rayons X, peuvent etre evaluee analytiquement et elles sont facilement parallelisables (sur le plate-forme GPU). Compare au blob classique du Kaisser-Bessel, la nouvelle base a une structure multi-echelle: une image est la somme des translations et des dilatations d'un chapeau Mexicain radial. Les images medicales typiques sont compressibles sous cette base, ce qui entraine que le systeme de la representation parcimonieuse intervenu dans les algorithmes ordinaires de CS n'y est plus necessaire. Des simulations numeriques en 2D ont montre que, compare a l'approche equivalente basee sur la base de pixel ou d'ondelette, les algorithmes du TV et du l1 existantes sont plus efficaces et les reconstructions ont de meilleures qualites visuelles. Cette nouvelle approche a ete egalement validee sur des donnees experimentales bi-dimensionelles, ou on a observe que le nombre de projection peut etre reduit

  6. 16 CFR 680.23 - Contents of opt-out notice; consolidated and equivalent notices.

    Science.gov (United States)

    2010-01-01

    ... equivalent notices. 680.23 Section 680.23 Commercial Practices FEDERAL TRADE COMMISSION THE FAIR CREDIT REPORTING ACT AFFILIATE MARKETING § 680.23 Contents of opt-out notice; consolidated and equivalent notices... receiving marketing than is required by this part, the requirements of this section may be satisfied by...

  7. Wind farm design in complex terrain: the FarmOpt methodology

    DEFF Research Database (Denmark)

    Feng, Ju; Shen, Wen Zhong; Hansen, Kurt Schaldemose

    layout optimization algorithms. Various constraints are also modelled and considered in the design optimization problem for maximizing the annual energy production (AEP). A case study is presented to illustrate the effectiveness of the methodology. Further developments of the FarmOpt tool are also...

  8. The effect of including an opt-out option in discrete choice experiments

    NARCIS (Netherlands)

    J. Veldwijk (Jorien); M.S. Lambooij (Mattijs); E.W. de Bekker-Grob (Esther); H.A. Smit (Henriëtte); G.A. De Wit (G. Ardine)

    2014-01-01

    markdownabstractObjective: to determine to what extent the inclusion of an opt-out option in a DCE may have an effect on choice behaviour and therefore might influence the attribute level estimates, the relative importance of the attributes and calculated tradeoffs. Methods: 781 Dutch Type 2

  9. Economic impact of the Commission's 'opt-out' proposal on the use of approved GM crops

    NARCIS (Netherlands)

    Hoste, R.; Wagenberg, van C.P.A.; Wijnands, J.H.M.

    2015-01-01

    The European Commission proposed the opportunity for individual EU Member States to restrict or prohibit the use of GMOs in food or feed on their territory (a national ‘opt-out’). The economic impact on individual sectors of the feed and food chain (the vegetable oil and meal industry, trade, animal

  10. 12 CFR 216.15 - Other exceptions to notice and opt out requirements.

    Science.gov (United States)

    2010-01-01

    ... insurance to the consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out... RESERVE SYSTEM PRIVACY OF CONSUMER FINANCIAL INFORMATION (REGULATION P) Exceptions § 216.15 Other... consent or at the direction of the consumer, provided that the consumer has not revoked the consent or...

  11. 16 CFR 313.15 - Other exceptions to notice and opt out requirements.

    Science.gov (United States)

    2010-01-01

    ... consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out of future... ACTS OF CONGRESS PRIVACY OF CONSUMER FINANCIAL INFORMATION Exceptions § 313.15 Other exceptions to... at the direction of the consumer, provided that the consumer has not revoked the consent or direction...

  12. 12 CFR 332.15 - Other exceptions to notice and opt out requirements.

    Science.gov (United States)

    2010-01-01

    ... insurance to the consumer. (2) A consumer may revoke consent by subsequently exercising the right to opt out... STATEMENTS OF GENERAL POLICY PRIVACY OF CONSUMER FINANCIAL INFORMATION Exceptions § 332.15 Other exceptions... consent or at the direction of the consumer, provided that the consumer has not revoked the consent or...

  13. 12 CFR 41.25 - Reasonable and simple methods of opting out.

    Science.gov (United States)

    2010-01-01

    ... exercising an opt-out right do not include— (i) Requiring the consumer to write his or her own letter; (ii.... A bank must not use eligibility information about a consumer that it receives from an affiliate to make a solicitation to the consumer about its products or services, unless the consumer is provided a...

  14. 12 CFR 717.25 - Reasonable and simple methods of opting out.

    Science.gov (United States)

    2010-01-01

    ... simple methods for exercising an opt-out right do not include— (i) Requiring the consumer to write his or... out. (a) In general. You must not use eligibility information about a consumer that you receive from an affiliate to make a solicitation to the consumer about your products or services, unless the...

  15. Acceptability of routine offer of HIV testing (opt-out approach) among ...

    African Journals Online (AJOL)

    Background: With the introduction of the opt out HIV testing policy in Ghana, the HIV test is offered routinely to all pregnant women unless they decline testing. Objective: To assess acceptability of the routine offer of HIV testing antenatal clinic (ANC) clients in the Wa municipality, Ghana. Design: Cross-sectional study of 270 ...

  16. Can a Repeated Opt-Out Reminder mitigate hypothetical bias in discrete choice experiments?

    DEFF Research Database (Denmark)

    Alemu, Mohammed Hussen; Olsen, Søren Bøye

    2018-01-01

    In this paper, we test whether a Repeated Opt-Out Reminder (ROOR) can mitigate hypothetical bias in stated discrete choice experiments (DCE). The data originate from a field experiment concerning consumer preferences for a novel food product made from cricket flour. Utilising a between...

  17. 12 CFR 571.23 - Contents of opt-out notice; consolidated and equivalent notices.

    Science.gov (United States)

    2010-01-01

    ... TREASURY FAIR CREDIT REPORTING Affiliate Marketing § 571.23 Contents of opt-out notice; consolidated and... concise, and must accurately disclose: (i) The name of the affiliate(s) providing the notice. If the notice is provided jointly by multiple affiliates and each affiliate shares a common name, such as “ABC...

  18. 12 CFR 717.23 - Contents of opt-out notice; consolidated and equivalent notices.

    Science.gov (United States)

    2010-01-01

    ... AFFECTING CREDIT UNIONS FAIR CREDIT REPORTING Affiliate Marketing § 717.23 Contents of opt-out notice..., conspicuous, and concise, and must accurately disclose: (i) The name of the affiliate(s) providing the notice. If the notice is provided jointly by multiple affiliates and each affiliate shares a common name...

  19. 17 CFR 248.13 - Exception to opt out requirements for service providers and joint marketing.

    Science.gov (United States)

    2010-04-01

    ... include marketing of your own products or services or marketing of financial products or services offered... requirements for service providers and joint marketing. 248.13 Section 248.13 Commodity and Securities... Consumer Financial Information and Safeguarding Personal Information Exceptions § 248.13 Exception to opt...

  20. 12 CFR 222.21 - Affiliate marketing opt-out and exceptions.

    Science.gov (United States)

    2010-01-01

    ... solicitation for marketing purposes to a consumer with whom you have a pre-existing business relationship; (2... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Affiliate marketing opt-out and exceptions. 222... FEDERAL RESERVE SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.21 Affiliate...

  1. 17 CFR 248.121 - Affiliate marketing opt out and exceptions.

    Science.gov (United States)

    2010-04-01

    ... business relationship with the consumer. (b) Making marketing solicitations—(1) In general. For purposes of... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Affiliate marketing opt out... COMMISSION (CONTINUED) REGULATIONS S-P AND S-AM Regulation S-AM: Limitations on Affiliate Marketing § 248.121...

  2. 12 CFR 222.22 - Scope and duration of opt-out.

    Science.gov (United States)

    2010-01-01

    ... SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.22 Scope and duration of opt-out.... (2) Continuing relationship—(i) In general. If the consumer establishes a continuing relationship... connection with— (A) A single continuing relationship or multiple continuing relationships that the consumer...

  3. 12 CFR 334.26 - Delivery of opt-out notices.

    Science.gov (United States)

    2010-01-01

    ... POLICY FAIR CREDIT REPORTING Affiliate Marketing § 334.26 Delivery of opt-out notices. (a) In general... the notice; or (4) Posts the notice on the Internet Web site at which the consumer obtained a product... notice; or (3) Posts the notice on an Internet Web site without requiring the consumer to acknowledge...

  4. 12 CFR 222.26 - Delivery of opt-out notices.

    Science.gov (United States)

    2010-01-01

    ... SYSTEM FAIR CREDIT REPORTING (REGULATION V) Affiliate Marketing § 222.26 Delivery of opt-out notices. (a... the affiliate providing the notice; or (4) Posts the notice on the Internet Web site at which the... affiliate providing the notice; or (3) Posts the notice on an Internet Web site without requiring the...

  5. Computerized tomography

    International Nuclear Information System (INIS)

    Caille, J.M.; Salamon, G.

    1980-01-01

    As X-ray Ct becomes more commonplace, other techniques of investigation using roughly comparable hardware and software have appeared. Positron-Emission Tomography already provides indispensable physiological and physio-pathological information. Similarly, in the histo-chemical field, Nuclear Magnetic Resonance seems very promising. Some of these new techniques will no doubt shortly be considered as essential as CT in establishing accurate diagnoses non-invasively. (orig./VJ) [de

  6. Computed tomography

    International Nuclear Information System (INIS)

    Andre, M.; Resnick, D.

    1988-01-01

    Computed tomography (CT) has matured into a reliable and prominent tool for study of the muscoloskeletal system. When it was introduced in 1973, it was unique in many ways and posed a challenge to interpretation. It is in these unique features, however, that its advantages lie in comparison with conventional techniques. These advantages will be described in a spectrum of important applications in orthopedics and rheumatology

  7. Opt-out of voluntary HIV testing: a Singapore hospital's experience.

    Directory of Open Access Journals (Sweden)

    Arlene C Chua

    Full Text Available INTRODUCTION: Since 2008, the Singapore Ministry of Health (MOH has expanded HIV testing by increasing anonymous HIV test sites, as well as issuing a directive to hospitals to offer routine voluntary opt out inpatient HIV testing. We reviewed this program implemented at the end of 2008 at Tan Tock Seng Hospital (TTSH, the second largest acute care general hospital in Singapore. METHODS AND FINDINGS: From January 2009 to December 2010, all inpatients aged greater or equal than 21 years were screened for HIV unless they declined or were not eligible for screening. We reviewed the implementation of the Opt Out testing policy. There were a total of 93,211 admissions; 41,543 patients were included based on HIV screening program eligibility criteria. Among those included, 79% (n = 32,675 opted out of HIV screening. The overall acceptance rate was 21%. Majority of eligible patients who were tested (63% were men. The mean age of tested patients was 52 years. The opt out rate was significantly higher among females (OR: 1.5, 95%CI: 1.4-1.6, aged >60 years (OR: 2.3, 95%CI: 2.2-2.4 and Chinese ethnicity (OR: 1.7, 95%CI:1.6-1.8. The false positive rate of the HIV screening test is 0.56%. The proportion of patients with HIV infection among those who underwent HIV screening is 0.18%. All 16 confirmed HIV patients were linked to care. CONCLUSION: The default opt-in rate of inpatient HIV testing was low at Tan Tock Seng Hospital, Singapore. Efforts to address individual HIV risk perception and campaigns against HIV stigma are needed to encourage more individuals to be tested for HIV.

  8. Opt-out of voluntary HIV testing: a Singapore hospital's experience.

    Science.gov (United States)

    Chua, Arlene C; Leo, Yee Sin; Cavailler, Philippe; Chu, Christine; Ng, Aloysius; Ng, Oon Tek; Krishnan, Prabha

    2012-01-01

    Since 2008, the Singapore Ministry of Health (MOH) has expanded HIV testing by increasing anonymous HIV test sites, as well as issuing a directive to hospitals to offer routine voluntary opt out inpatient HIV testing. We reviewed this program implemented at the end of 2008 at Tan Tock Seng Hospital (TTSH), the second largest acute care general hospital in Singapore. From January 2009 to December 2010, all inpatients aged greater or equal than 21 years were screened for HIV unless they declined or were not eligible for screening. We reviewed the implementation of the Opt Out testing policy. There were a total of 93,211 admissions; 41,543 patients were included based on HIV screening program eligibility criteria. Among those included, 79% (n = 32,675) opted out of HIV screening. The overall acceptance rate was 21%. Majority of eligible patients who were tested (63%) were men. The mean age of tested patients was 52 years. The opt out rate was significantly higher among females (OR: 1.5, 95%CI: 1.4-1.6), aged >60 years (OR: 2.3, 95%CI: 2.2-2.4) and Chinese ethnicity (OR: 1.7, 95%CI:1.6-1.8). The false positive rate of the HIV screening test is 0.56%. The proportion of patients with HIV infection among those who underwent HIV screening is 0.18%. All 16 confirmed HIV patients were linked to care. The default opt-in rate of inpatient HIV testing was low at Tan Tock Seng Hospital, Singapore. Efforts to address individual HIV risk perception and campaigns against HIV stigma are needed to encourage more individuals to be tested for HIV.

  9. Industrial Computed Tomography using Proximal Algorithm

    KAUST Repository

    Zang, Guangming

    2016-01-01

    fewer projections. We compare our framework to state-of-the-art methods and existing popular software tomography reconstruction packages, on both synthetic and real datasets, and show superior reconstruction quality, especially from noisy data and a

  10. Markerless four-dimensional-cone beam computed tomography projection-phase sorting using prior knowledge and patient motion modeling: A feasibility study

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2017-01-01

    Conclusion: The study demonstrated the feasibility of using PCA coefficients for 4D-CBCT projection-phase sorting. High sorting accuracy in both digital phantoms and patient cases was achieved. This method provides an accurate and robust tool for automatic 4D-CBCT projection sorting using 3D motion modeling without the need of external surrogate or internal markers.

  11. X-ray Computed Tomography.

    Science.gov (United States)

    Michael, Greg

    2001-01-01

    Describes computed tomography (CT), a medical imaging technique that produces images of transaxial planes through the human body. A CT image is reconstructed mathematically from a large number of one-dimensional projections of a plane. The technique is used in radiological examinations and radiotherapy treatment planning. (Author/MM)

  12. Computed Tomography Image Quality Evaluation of a New Iterative Reconstruction Algorithm in the Abdomen (Adaptive Statistical Iterative Reconstruction-V) a Comparison With Model-Based Iterative Reconstruction, Adaptive Statistical Iterative Reconstruction, and Filtered Back Projection Reconstructions.

    Science.gov (United States)

    Goodenberger, Martin H; Wagner-Bartak, Nicolaus A; Gupta, Shiva; Liu, Xinming; Yap, Ramon Q; Sun, Jia; Tamm, Eric P; Jensen, Corey T

    The purpose of this study was to compare abdominopelvic computed tomography images reconstructed with adaptive statistical iterative reconstruction-V (ASIR-V) with model-based iterative reconstruction (Veo 3.0), ASIR, and filtered back projection (FBP). Abdominopelvic computed tomography scans for 36 patients (26 males and 10 females) were reconstructed using FBP, ASIR (80%), Veo 3.0, and ASIR-V (30%, 60%, 90%). Mean ± SD patient age was 32 ± 10 years with mean ± SD body mass index of 26.9 ± 4.4 kg/m. Images were reviewed by 2 independent readers in a blinded, randomized fashion. Hounsfield unit, noise, and contrast-to-noise ratio (CNR) values were calculated for each reconstruction algorithm for further comparison. Phantom evaluation of low-contrast detectability (LCD) and high-contrast resolution was performed. Adaptive statistical iterative reconstruction-V 30%, ASIR-V 60%, and ASIR 80% were generally superior qualitatively compared with ASIR-V 90%, Veo 3.0, and FBP (P ASIR-V 60% with respective CNR values of 5.54 ± 2.39, 8.78 ± 3.15, and 3.49 ± 1.77 (P ASIR 80% had the best and worst spatial resolution, respectively. Adaptive statistical iterative reconstruction-V 30% and ASIR-V 60% provided the best combination of qualitative and quantitative performance. Adaptive statistical iterative reconstruction 80% was equivalent qualitatively, but demonstrated inferior spatial resolution and LCD.

  13. 40 CFR Appendix A to Subpart III... - States With Approved State Implementation Plan Revisions Concerning CAIR SO2 Opt-In Units

    Science.gov (United States)

    2010-07-01

    ... Implementation Plan Revisions Concerning CAIR SO2 Opt-In Units A Appendix A to Subpart III of Part 97 Protection... BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS CAIR SO2 Opt-in Units Pt. 97, Subpt. III... Concerning CAIR SO2 Opt-In Units 1. The following States have State Implementation Plan revisions under § 51...

  14. Is opting out of the peaceful uses of nuclear power a responsible approach to take?

    International Nuclear Information System (INIS)

    Becker, K.

    1999-01-01

    This was the topic of an Expert Meeting arranged by the VDI-Gesellschaft fuer Energietechnik at the Berlin Palace Hotel on September 28-29, 1999 and attended by roughly one hundred experts, almost exclusively from Germany. The meeting was organized to examine the economic impact of Germany's sole opting out of a high technology in the face of a growing worldwide energy requirement, and whether this approach will allow the objectives of carbon dioxide reduction to be achieved in the interest of climate protection. The detailed points discussed at the meeting included the economic consequences for Germany arising from the country's opting out of the use of nuclear power; the preservation of competence in nuclear technology; the future role of nuclear power in the EU; the energy options existing for climate protection. In addition, political discussions were held with representatives of the political parties. (orig.) [de

  15. eCodonOpt: a systematic computational framework for optimizing codon usage in directed evolution experiments

    OpenAIRE

    Moore, Gregory L.; Maranas, Costas D.

    2002-01-01

    We present a systematic computational framework, eCodonOpt, for designing parental DNA sequences for directed evolution experiments through codon usage optimization. Given a set of homologous parental proteins to be recombined at the DNA level, the optimal DNA sequences encoding these proteins are sought for a given diversity objective. We find that the free energy of annealing between the recombining DNA sequences is a much better descriptor of the extent of crossover formation than sequence...

  16. Which Factors Drive the Decision to Boycott and Opt Out of Research Rankings?

    OpenAIRE

    Michael Berlemann; Justus Haucap

    2012-01-01

    This note contains an empirical analysis of the decision of German-speaking business scholars to boycott and opt out of the best known research ranking of business scholars, initiated and published by Germany’s largest business daily, Handelsblatt. Our analysis indicates that scientists who are more senior (already have a longer academic career) and scientists who have been either less successful or less eager to publish their research in internationally well renown journals with high impac...

  17. Opt-out of Voluntary HIV Testing: A Singapore Hospital's Experience

    OpenAIRE

    Chua, Arlene C.; Leo, Yee Sin; Cavailler, Philippe; Chu, Christine; Ng, Aloysius; Ng, Oon Tek; Krishnan, Prabha

    2012-01-01

    INTRODUCTION: Since 2008, the Singapore Ministry of Health (MOH) has expanded HIV testing by increasing anonymous HIV test sites, as well as issuing a directive to hospitals to offer routine voluntary opt out inpatient HIV testing. We reviewed this program implemented at the end of 2008 at Tan Tock Seng Hospital (TTSH), the second largest acute care general hospital in Singapore. METHODS AND FINDINGS: From January 2009 to December 2010, all inpatients aged greater or equal than 21 years were ...

  18. Deemed consent: assessing the new opt-out approach to organ procurement in Wales.

    Science.gov (United States)

    Albertsen, Andreas

    2018-05-01

    In December 2015, Wales became the first country in the UK to move away from an opt-in system in organ procurement. The new legislation introduces the concept of deemed consent whereby a person who neither opt in nor opt out is deemed to have consented to donation. The data released by the National Health Service (NHS) in July 2017 provide an excellent opportunity to assess this legislation in light of concerns that it would decrease procurement rates for living and deceased donation, as well as sparking an increase in family refusals. None of these concerns have come to pass, with Wales experiencing more registered donors, fewer family refusals and more living donations. However, as the number of actual donors has dropped slightly from a high level, the situation must be monitored closely in the years to come. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. The Opt-Out Continuation: Education, Work, and Motherhood from 1984 to 2012

    Directory of Open Access Journals (Sweden)

    Tanya Byker

    2016-08-01

    Full Text Available Debate about an increasing trend in highly educated women dropping out of the labor force to care for children—an opt-out revolution—has been considerable. I use unique features of the of Survey of Income and Program Participation—a large nationally representative sample, longitudinal structure, monthly labor-force outcomes, and repeated panels—to study trends in women's birth-related career interruptions over time and across the education spectrum. Methodologically, I use event studies to compare women's monthly labor-force outcomes on the extensive and intensive margins from twenty-four months before to twenty-four months after births in the 1980s, 1990s, and 2000s. Rather than an abrupt change in opting out, I find that the pattern of birth-related interruptions has changed surprisingly little over the past thirty years—substantial and sustained interruptions remain common for mothers in all education categories. Rather than a revolution, I find an opt-out continuation.

  20. OptFlux: an open-source software platform for in silico metabolic engineering.

    Science.gov (United States)

    Rocha, Isabel; Maia, Paulo; Evangelista, Pedro; Vilaça, Paulo; Soares, Simão; Pinto, José P; Nielsen, Jens; Patil, Kiran R; Ferreira, Eugénio C; Rocha, Miguel

    2010-04-19

    Over the last few years a number of methods have been proposed for the phenotype simulation of microorganisms under different environmental and genetic conditions. These have been used as the basis to support the discovery of successful genetic modifications of the microbial metabolism to address industrial goals. However, the use of these methods has been restricted to bioinformaticians or other expert researchers. The main aim of this work is, therefore, to provide a user-friendly computational tool for Metabolic Engineering applications. OptFlux is an open-source and modular software aimed at being the reference computational application in the field. It is the first tool to incorporate strain optimization tasks, i.e., the identification of Metabolic Engineering targets, using Evolutionary Algorithms/Simulated Annealing metaheuristics or the previously proposed OptKnock algorithm. It also allows the use of stoichiometric metabolic models for (i) phenotype simulation of both wild-type and mutant organisms, using the methods of Flux Balance Analysis, Minimization of Metabolic Adjustment or Regulatory on/off Minimization of Metabolic flux changes, (ii) Metabolic Flux Analysis, computing the admissible flux space given a set of measured fluxes, and (iii) pathway analysis through the calculation of Elementary Flux Modes. OptFlux also contemplates several methods for model simplification and other pre-processing operations aimed at reducing the search space for optimization algorithms. The software supports importing/exporting to several flat file formats and it is compatible with the SBML standard. OptFlux has a visualization module that allows the analysis of the model structure that is compatible with the layout information of Cell Designer, allowing the superimposition of simulation results with the model graph. The OptFlux software is freely available, together with documentation and other resources, thus bridging the gap from research in strain optimization

  1. Activity of OPT-80, a novel macrocycle, compared with those of eight other agents against selected anaerobic species.

    Science.gov (United States)

    Credito, Kim L; Appelbaum, Peter C

    2004-11-01

    Agar dilution MIC was used to compare activities of OPT-80, linezolid, vancomycin, teicoplanin, quinupristin/dalfopristin, amoxicillin/clavulanate, imipenem, clindamycin, and metronidazole against 350 gram-positive and -negative anaerobes. OPT-80 was active against gram-positive strains only, especially Clostridium spp. (85 strains tested, including 21 strains of C. difficile), with MICs ranging between

  2. X-ray computerized tomography based on the method of reciprocal projection with filtration by double differentiation. Procedure and information peculiarities

    International Nuclear Information System (INIS)

    Vajnberg, Eh.I.; Kazak, I.A.; Fajngojz, M.L.

    1985-01-01

    The results of experimental evaluation of procedure and information peculiarities of the method of reciprocal projection with filtration of projections by double differentiation (RPFDD) for the monitoring of industrial products are generalized. Succession of stages n the RPFDD method permits to separately optimize reconstruction of high-frequeny and low-frequency tomogram structure which sharply reduces the acuteness of contradictions of conventional scheme between the required increase of accuracy and intolerable growth of computerized charges. High accuracy of evaluation of the linear attenuation factor of low-frequency structures in a wide range of densities at the last stage of RPFDD scheme is attained despite the non-conventionally small range of values at earlier stages of computerized processing

  3. X-ray Compton line scan tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kupsch, Andreas; Lange, Axel; Jaenisch, Gerd-Ruediger [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany). Fachgruppe 8.5 - Mikro-ZfP; Hentschel, Manfred P. [Technische Univ. Berlin (Germany); Kardjilov, Nikolay; Markoetter, Henning; Hilger, Andre; Manke, Ingo [Helmholtz-Zentrum Berlin (HZB) (Germany); Toetzke, Christian [Potsdam Univ. (Germany)

    2015-07-01

    The potentials of incoherent X-ray scattering (Compton) computed tomography (CT) are investigated. The imaging of materials of very different atomic number or density at once is generally a perpetual challenge for X-ray tomography or radiography. In a basic laboratory set-up for simultaneous perpendicular Compton scattering and direct beam attenuation tomography are conducted by single channel photon counting line scans. This results in asymmetric distortions of the projection profiles of the scattering CT data set. In a first approach, corrections of Compton scattering data by taking advantage of rotational symmetry yield tomograms without major geometric artefacts. A cylindrical sample composed of PE, PA, PVC, glass and wood demonstrates similar Compton contrast for all the substances, while the conventional absorption tomogram only reveals the two high order materials. Comparison to neutron tomography reveals astonishing similarities except for the glass component (without hydrogen). Therefore, Compton CT offers the potential to replace neutron tomography, which requires much more efforts.

  4. Photoacoustic Tomography

    Science.gov (United States)

    Wang, Lihong V.

    Photoacoustic tomography (PAT) refers to imaging that is based on the photoacoustic effect. Although the photoacoustic effect as a physical phenomenon was first reported on by Alexander Graham Bell in 1880 [1], PAT as an imaging technology was developed only after the advent of ultrasonic transducers, computers, and lasers [2-31]. A review on biomedical photoacoustics is available [32]. The motivation for PAT is to combine optical-absorption contrast with ultrasonic spatial resolution for deep imaging in the optical quasi-diffusive or diffusive regime. In PAT, the tissue is irradiated by usually a short-pulsed laser beam to achieve a thermal and acoustic impulse response (Fig. 19.1). Locally absorbed light is converted into heat, which is further converted to a pressure rise via thermo-elastic expansion. The initial pressure rise - determined by the local optical absorption coefficient (μ â ), fluence (ψ) and other thermal and mechanical properties - propagates as an ultrasonic wave, which is referred to as a photoacoustic wave.

  5. Axial tomography

    International Nuclear Information System (INIS)

    Brueckner, K.A.; Lewis, J.H.

    1979-01-01

    The invention relates to axial tomography, sometimes referred to as cross-sectional x-ray. The apparatus described may utilize the conventional x-ray or ultrasonic source and detector and scanning mechanism for producing the plurality of sets of radiation detector output signals. It has the means for storing the detector output signals in analog form with the signals of one set overlying the signals of another set so that signals resulting from radiation through a zone of the object being examined are summed at a corresponding zone in the storage device, typically an electronic storage tube. The summed signals are read from the storage device with a radially inversely proportional reader producing a second signal for storage, again typically in an electronic storage tube. These signals stored in the second storage device are read with Laplacian relation, with the resultant sigal being a video signal that may be connected to a TV monitor for display of the sectional image. In alternative embodiments, optical film systems and electrostatic systems are utilized. (JTA)

  6. Compressed sensing electron tomography

    International Nuclear Information System (INIS)

    Leary, Rowan; Saghi, Zineb; Midgley, Paul A.; Holland, Daniel J.

    2013-01-01

    The recent mathematical concept of compressed sensing (CS) asserts that a small number of well-chosen measurements can suffice to reconstruct signals that are amenable to sparse or compressible representation. In addition to powerful theoretical results, the principles of CS are being exploited increasingly across a range of experiments to yield substantial performance gains relative to conventional approaches. In this work we describe the application of CS to electron tomography (ET) reconstruction and demonstrate the efficacy of CS–ET with several example studies. Artefacts present in conventional ET reconstructions such as streaking, blurring of object boundaries and elongation are markedly reduced, and robust reconstruction is shown to be possible from far fewer projections than are normally used. The CS–ET approach enables more reliable quantitative analysis of the reconstructions as well as novel 3D studies from extremely limited data. - Highlights: • Compressed sensing (CS) theory and its application to electron tomography (ET) is described. • The practical implementation of CS–ET is outlined and its efficacy demonstrated with examples. • High fidelity tomographic reconstruction is possible from a small number of images. • The CS–ET reconstructions can be more reliably segmented and analysed quantitatively. • CS–ET is applicable to different image content by choice of an appropriate sparsifying transform

  7. k-OptForce: integrating kinetics with flux balance analysis for strain design.

    Directory of Open Access Journals (Sweden)

    Anupam Chowdhury

    2014-02-01

    Full Text Available Computational strain design protocols aim at the system-wide identification of intervention strategies for the enhanced production of biochemicals in microorganisms. Existing approaches relying solely on stoichiometry and rudimentary constraint-based regulation overlook the effects of metabolite concentrations and substrate-level enzyme regulation while identifying metabolic interventions. In this paper, we introduce k-OptForce, which integrates the available kinetic descriptions of metabolic steps with stoichiometric models to sharpen the prediction of intervention strategies for improving the bio-production of a chemical of interest. It enables identification of a minimal set of interventions comprised of both enzymatic parameter changes (for reactions with available kinetics and reaction flux changes (for reactions with only stoichiometric information. Application of k-OptForce to the overproduction of L-serine in E. coli and triacetic acid lactone (TAL in S. cerevisiae revealed that the identified interventions tend to cause less dramatic rearrangements of the flux distribution so as not to violate concentration bounds. In some cases the incorporation of kinetic information leads to the need for additional interventions as kinetic expressions render stoichiometry-only derived interventions infeasible by violating concentration bounds, whereas in other cases the kinetic expressions impart flux changes that favor the overproduction of the target product thereby requiring fewer direct interventions. A sensitivity analysis on metabolite concentrations shows that the required number of interventions can be significantly affected by changing the imposed bounds on metabolite concentrations. Furthermore, k-OptForce was capable of finding non-intuitive interventions aiming at alleviating the substrate-level inhibition of key enzymes in order to enhance the flux towards the product of interest, which cannot be captured by stoichiometry-alone analysis

  8. An update in proton probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sakellariou, A; Cholewa, M; Saint, A; Legge, G L.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Howard, J [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences

    1997-12-31

    The analysis of scanning transmission ion microscopy (STIM) tomography data is improved. The volumetric density information is obtained directly from an iterative convolution and back-projection (BFP) reconstruction method. The iterative method allows the effects of stopping-power to be incorporated easily. One draw back is that a priori constituency information is required for the iterative method to work However, this is of no concern because the iterative method was designed with PIXE tomography in mind. In this light, the a priori information will be obtained as the zeroth iteration of a PIXE tomography iterative reconstruction method. 4 refs., 1 tab., 4 figs.

  9. An update in proton probe tomography

    Energy Technology Data Exchange (ETDEWEB)

    Sakellariou, A.; Cholewa, M.; Saint, A.; Legge, G.L.F. [Melbourne Univ., Parkville, VIC (Australia). School of Physics; Howard, J. [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences

    1996-12-31

    The analysis of scanning transmission ion microscopy (STIM) tomography data is improved. The volumetric density information is obtained directly from an iterative convolution and back-projection (BFP) reconstruction method. The iterative method allows the effects of stopping-power to be incorporated easily. One draw back is that a priori constituency information is required for the iterative method to work However, this is of no concern because the iterative method was designed with PIXE tomography in mind. In this light, the a priori information will be obtained as the zeroth iteration of a PIXE tomography iterative reconstruction method. 4 refs., 1 tab., 4 figs.

  10. Development of emission computed tomography in Japan

    International Nuclear Information System (INIS)

    Tanaka, E.

    1984-01-01

    Two positron emission computed tomography (PCT) devices developed in Japan are described. One is for head and the other for wholebody. The devices show fairly quantitative images with slight modifications of the existing algorithms because they were developed based on filtered back-projection. The PCT device seems to be better than the single photon emission computed tomography (SPECT) since it provides adequade compensation for photon attenuation in patients. (M.A.C.) [pt

  11. Quantitative inspection by computerized tomography

    International Nuclear Information System (INIS)

    Lopes, R.T.; Assis, J.T. de; Jesus, E.F.O. de

    1989-01-01

    The computerized Tomography (CT) is a method of nondestructive testing, that furnish quantitative information, that permit the detection and accurate localization of defects, internal dimension measurement, and, measurement and chart of the density distribution. The CT technology is much versatile, not presenting restriction in relation to form, size or composition of the object. A tomographic system, projected and constructed in our laboratory is presented. The applications and limitation of this system, illustrated by tomographyc images, are shown. (V.R.B.)

  12. Optimizing Cofactor Specificity of Oxidoreductase Enzymes for the Generation of Microbial Production Strains—OptSwap

    DEFF Research Database (Denmark)

    King, Zachary A.; Feist, Adam

    2013-01-01

    Central oxidoreductase enzymes (eg, dehydrogenases, reductases) in microbial metabolism often have preferential binding specificity for one of the two major currency metabolites NAD(H) and NADP(H). These enzyme specificities result in a division of the metabolic functionality of the currency...... specificities of oxidoreductase enzyme and complementary reaction knockouts. Using the Escherichia coli genome-scale metabolic model iJO1366, OptSwap predicted eight growth-coupled production designs with significantly greater product yields or substrate-specific productivities than designs predicted with gene...

  13. OptFlux: an open-source software platform for in silico metabolic engineering

    DEFF Research Database (Denmark)

    Rocha, I.; Maia, P.; Evangelista, P.

    2010-01-01

    to address industrial goals. However, the use of these methods has been restricted to bioinformaticians or other expert researchers. The main aim of this work is, therefore, to provide a user-friendly computational tool for Metabolic Engineering applications. Results: OptFlux is an open-source and modular...... available a number of useful tools. Its open-source nature invites contributions by all those interested in making their methods available for the community. Given its plug-in based architecture it can be extended with new functionalities. Currently, several plug-ins are being developed, including network...

  14. The kids at Hamilton Elementary School: Purposes and practices for co-opting science

    Science.gov (United States)

    Ortiz, Loaiza

    The purpose of this study was to explore youth's purposes and motivations for engaging in science through the lens of science practices. The construct of science practices allowed me to see science in youths' lives in a holistic way, shaped by social, political, historical, economic and cultural forces. The framework for understanding urban youths' science practices is grounded in the intersections of critical and feminist theory, sociocultural learning theories, especially as applied in research in urban science education, and recent work in critical literacy studies. As I explored the answers to my research questions---(1) When 5th grade youth, living in predominantly Latino communities struggling with urban poverty, engage in science how and why do they co-opt science in ways that result in changes in participation in science? (2) What are the science practices that facilitate youths' coopting of science? And how are those practices framed by context (school, out-of-school), content (LiFE curriculum), and funds of knowledge? (3) In what ways are science practices expressions of youths' scientific literacy? And (4) In what ways do youth use science practices as tools for expressing identities and agency?---I engaged in feminist ethnography with embedded case studies. Data were collected in 2004 in school and in out of school settings. I recorded numerous informal conversations, interviews, and observations both during after-school and students' regular science and non-science classes. Findings describe how and why students co-opted science for purposes that make sense for their lives. These purposes included gaining and activating resources, building and maintaining social relationships, bridging home and school knowledge, positioning themselves with authority, and constructing science identities. Findings also explored what practices facilitated youth's co-opting of science. I highlighted three practices: making ideas public, storytelling and prioritizing and

  15. Vanishing vaccinations: why are so many Americans opting out of vaccinating their children?

    Science.gov (United States)

    Calandrillo, Steve P

    2004-01-01

    Vaccinations against life-threatening diseases are one of the greatest public health achievements in history. Literally millions of premature deaths have been prevented, and countless more children have been saved from disfiguring illness. While vaccinations carry unavoidable risks, the medical, social and economic benefits they confer have led all fifty states to enact compulsory childhood vaccination laws to stop the spread of preventable diseases. Today, however, vaccines are becoming a victim of their success--many individuals have never witnessed the debilitating diseases that vaccines protect against, allowing complacency toward immunization requirements to build. Antivaccination sentiment is growing fast in the United States, in large part due to the controversial and hotly disputed link between immunizations and autism. The internet worsens fears regarding vaccination safety, as at least a dozen websites publish alarming information about the risks of vaccines. Increasing numbers of parents are refusing immunizations for their children and seeking legally sanctioned exemptions instead, apparently fearing vaccines more than the underlying diseases that they protect against. A variety of factors are at play: religious and philosophical beliefs, freedom and individualism, misinformation about risk, and overperception of risk. State legislatures and health departments now face a difficult challenge: respecting individual rights and freedoms while also safeguarding the public welfare. Nearly all states allow vaccination exemptions for religious reasons and a growing number provide "philosophical" opt-outs as well. However, in all but a handful of jurisdictions, neither objection is seriously documented or verified. Often, the law requires a parent to do no more than simply check a box indicating she does not wish her child to receive immunizations. The problem is exacerbated by financial incentives schools have to encourage students to opt out of vaccinations

  16. The neutron computer tomography

    International Nuclear Information System (INIS)

    Matsumoto, G.; Krata, S.

    1983-01-01

    The method of computer tomography (CT) was applied for neutrons instead of X-rays. The neutron radiography image of samples was scanned by microphotometer to get the transmission data. This process was so time-consuming that the number of incident angles to samples could not be increased. The transmission data was processed by FACOM computer and CT image was gained. In the experiment at the Japan Research Reactor No. 4 at Tokai-mura with 18 projection angles, the resolution of paraffin in the aluminum block was less than 0.8 mm. In the experiment at Van de Graaf accelerator of Nagoya University, this same resolution was 1.2 mm because of the angle distribution of neutron beam. This experiment is the preliminary one, the facility which utilizes neutron television and video-recorder will be necessary for the next stage. (Auth.)

  17. Matlab enhanced multi-threaded tomography optimization sequence (MEMTOS)

    International Nuclear Information System (INIS)

    Lum, Edward S.; Pope, Chad L.

    2016-01-01

    Highlights: • Monte Carlo simulation of spent nuclear fuel assembly neutron computed tomography. • Optimized parallel calculations conducted from within the MATLAB environment. • Projection difference technique used to identify anomalies in spent nuclear fuel assemblies. - Abstract: One challenge associated with spent nuclear fuel assemblies is the lack of non-destructive analysis techniques to determine if fuel pins have been removed or replaced or if there are significant defects associated with fuel pins deep within a fuel assembly. Neutron computed tomography is a promising technique for addressing these qualitative issues. Monte Carlo simulation of spent nuclear fuel neutron computed tomography allows inexpensive process investigation and optimization. The main purpose of this work is to provide a fully automated advanced simulation framework for the analysis of spent nuclear fuel inspection using neutron computed tomography. The simulation framework, called Matlab Enhanced Multi-Threaded Tomography Optimization Sequence (MEMTOS) not only automates the simulation process, but also generates superior tomography image results. MEMTOS is written in the MATLAB scripting language and addresses file management, parallel Monte Carlo execution, results extraction, and tomography image generation. This paper describes the mathematical basis for neutron computed tomography, the Monte Carlo technique used to simulate neutron computed tomography, and the overall tomography simulation optimization algorithm. Sequence results presented include overall simulation speed enhancement, tomography and image results obtained for Experimental Breeder Reactor II spent fuel assemblies and light water reactor fuel assemblies. Optimization using a projection difference technique are also described.

  18. Algorithmic fundamentals of computerized tomography and of transverse analogue tomography

    International Nuclear Information System (INIS)

    Heckmann, K.

    1981-01-01

    Computerized tomography and transverse analogue tomography are two different approaches to the same goal, namely, transverse tomography. The algorithm is discussed and compared. Transverse tomography appears capable of further development, judging by this comparison. (orig.) [de

  19. OPT-TWO: Calculation code for two-dimensional MOX fuel models in the optimum concentration distribution

    International Nuclear Information System (INIS)

    Sato, Shohei; Okuno, Hiroshi; Sakai, Tomohiro

    2007-08-01

    OPT-TWO is a calculation code which calculates the optimum concentration distribution, i.e., the most conservative concentration distribution in the aspect of nuclear criticality safety, of MOX (mixed uranium and plutonium oxide) fuels in the two-dimensional system. To achieve the optimum concentration distribution, we apply the principle of flattened fuel importance distribution with which the fuel system has the highest reactivity. Based on this principle, OPT-TWO takes the following 3 calculation steps iteratively to achieve the optimum concentration distribution with flattened fuel importance: (1) the forward and adjoint neutron fluxes, and the neutron multiplication factor, with TWOTRAN code which is a two-dimensional neutron transport code based on the SN method, (2) the fuel importance, and (3) the quantity of the transferring fuel. In OPT-TWO, the components of MOX fuel are MOX powder, uranium dioxide powder and additive. This report describes the content of the calculation, the computational method, and the installation method of the OPT-TWO, and also describes the application method of the criticality calculation of OPT-TWO. (author)

  20. The modification of hybrid method of ant colony optimization, particle swarm optimization and 3-OPT algorithm in traveling salesman problem

    Science.gov (United States)

    Hertono, G. F.; Ubadah; Handari, B. D.

    2018-03-01

    The traveling salesman problem (TSP) is a famous problem in finding the shortest tour to visit every vertex exactly once, except the first vertex, given a set of vertices. This paper discusses three modification methods to solve TSP by combining Ant Colony Optimization (ACO), Particle Swarm Optimization (PSO) and 3-Opt Algorithm. The ACO is used to find the solution of TSP, in which the PSO is implemented to find the best value of parameters α and β that are used in ACO.In order to reduce the total of tour length from the feasible solution obtained by ACO, then the 3-Opt will be used. In the first modification, the 3-Opt is used to reduce the total tour length from the feasible solutions obtained at each iteration, meanwhile, as the second modification, 3-Opt is used to reduce the total tour length from the entire solution obtained at every iteration. In the third modification, 3-Opt is used to reduce the total tour length from different solutions obtained at each iteration. Results are tested using 6 benchmark problems taken from TSPLIB by calculating the relative error to the best known solution as well as the running time. Among those modifications, only the second and third modification give satisfactory results except the second one needs more execution time compare to the third modifications.

  1. Differential Bees Flux Balance Analysis with OptKnock for in silico microbial strains optimization.

    Directory of Open Access Journals (Sweden)

    Yee Wen Choon

    Full Text Available Microbial strains optimization for the overproduction of desired phenotype has been a popular topic in recent years. The strains can be optimized through several techniques in the field of genetic engineering. Gene knockout is a genetic engineering technique that can engineer the metabolism of microbial cells with the objective to obtain desirable phenotypes. However, the complexities of the metabolic networks have made the process to identify the effects of genetic modification on the desirable phenotypes challenging. Furthermore, a vast number of reactions in cellular metabolism often lead to the combinatorial problem in obtaining optimal gene deletion strategy. Basically, the size of a genome-scale metabolic model is usually large. As the size of the problem increases, the computation time increases exponentially. In this paper, we propose Differential Bees Flux Balance Analysis (DBFBA with OptKnock to identify optimal gene knockout strategies for maximizing the production yield of desired phenotypes while sustaining the growth rate. This proposed method functions by improving the performance of a hybrid of Bees Algorithm and Flux Balance Analysis (BAFBA by hybridizing Differential Evolution (DE algorithm into neighborhood searching strategy of BAFBA. In addition, DBFBA is integrated with OptKnock to validate the results for improving the reliability the work. Through several experiments conducted on Escherichia coli, Bacillus subtilis, and Clostridium thermocellum as the model organisms, DBFBA has shown a better performance in terms of computational time, stability, growth rate, and production yield of desired phenotypes compared to the methods used in previous works.

  2. Users manual for Opt-MS : local methods for simplicial mesh smoothing and untangling.

    Energy Technology Data Exchange (ETDEWEB)

    Freitag, L.

    1999-07-20

    Creating meshes containing good-quality elements is a challenging, yet critical, problem facing computational scientists today. Several researchers have shown that the size of the mesh, the shape of the elements within that mesh, and their relationship to the physical application of interest can profoundly affect the efficiency and accuracy of many numerical approximation techniques. If the application contains anisotropic physics, the mesh can be improved by considering both local characteristics of the approximate application solution and the geometry of the computational domain. If the application is isotropic, regularly shaped elements in the mesh reduce the discretization error, and the mesh can be improved a priori by considering geometric criteria only. The Opt-MS package provides several local node point smoothing techniques that improve elements in the mesh by adjusting grid point location using geometric, criteria. The package is easy to use; only three subroutine calls are required for the user to begin using the software. The package is also flexible; the user may change the technique, function, or dimension of the problem at any time during the mesh smoothing process. Opt-MS is designed to interface with C and C++ codes, ad examples for both two-and three-dimensional meshes are provided.

  3. The gastropod shell has been co-opted to kill parasitic nematodes.

    Science.gov (United States)

    Rae, R

    2017-07-06

    Exoskeletons have evolved 18 times independently over 550 MYA and are essential for the success of the Gastropoda. The gastropod shell shows a vast array of different sizes, shapes and structures, and is made of conchiolin and calcium carbonate, which provides protection from predators and extreme environmental conditions. Here, I report that the gastropod shell has another function and has been co-opted as a defense system to encase and kill parasitic nematodes. Upon infection, cells on the inner layer of the shell adhere to the nematode cuticle, swarm over its body and fuse it to the inside of the shell. Shells of wild Cepaea nemoralis, C. hortensis and Cornu aspersum from around the U.K. are heavily infected with several nematode species including Caenorhabditis elegans. By examining conchology collections I show that nematodes are permanently fixed in shells for hundreds of years and that nematode encapsulation is a pleisomorphic trait, prevalent in both the achatinoid and non-achatinoid clades of the Stylommatophora (and slugs and shelled slugs), which diverged 90-130 MYA. Taken together, these results show that the shell also evolved to kill parasitic nematodes and this is the only example of an exoskeleton that has been co-opted as an immune system.

  4. Correlates of HIV testing refusal among emergency department patients in the opt-out testing era.

    Science.gov (United States)

    Setse, Rosanna W; Maxwell, Celia J

    2014-05-01

    Opt-out HIV screening is recommended by the CDC for patients in all healthcare settings. We examined correlates of HIV testing refusal among urban emergency department (ED) patients. Confidential free HIV screening was offered to 32,633 ED patients in an urban tertiary care facility in Washington, DC, during May 2007-December 2011. Demographic differences in testing refusals were examined using χ(2) tests and generalized linear models. HIV testing refusal rates were 47.7 % 95 % CI (46.7-48.7), 11.7 % (11.0-12.4), 10.7 % (10.0-11.4), 16.9 % (15.9-17.9) and 26.9 % (25.6-28.2) in 2007, 2008, 2009, 2010 and 2011 respectively. Persons 33-54 years of age [adjusted prevalence ratio (APR) 1.42, (1.36-1.48)] and those ≥ 55 years [APR 1.39 (1.31-1.47)], versus 33-54 years; and females versus males [APR 1.07 (1.02-1.11)] were more likely to refuse testing. Opt-out HIV testing is feasible and sustainable in urban ED settings. Efforts are needed to encourage testing among older patients and women.

  5. Opt-Out Patient Navigation to Improve Breast and Cervical Cancer Screening Among Homeless Women.

    Science.gov (United States)

    Asgary, Ramin; Naderi, Ramesh; Wisnivesky, Juan

    2017-09-01

    A patient navigation model was implemented to improve breast and cervical cancer screening among women who were homeless in five shelters and shelter clinics in New York City in 2014. Navigation consisted of opt-out screening to eligible women; cancer health and screening education; scheduling and following up for screening completion, obtaining, and communicating results to patients and providers; and care coordination with social services organizations. Women (n = 162, aged 21-74, 58% black) completed mammogram (88%) and Pap testing (83%) from baselines of 59% and 50%, respectively. There was no association between mental health or substance abuse and screening completion. Adjusted analysis showed a significant association between refusing/missing Pap testing and older age (odds ratio [OR] 1.12, 95% confidence interval [CI] 1.04-1.20); independent predictors of mammogram included more pregnancies (OR 0.57, 95% CI 0.37-0.88) and older age (OR 0.84, 95% CI 0.79-0.90). Opt-out patient navigation is feasible and effective and may mitigate multilevel barriers to cancer screening among women with unstable housing.

  6. Audio-Visual Biofeedback Does Not Improve the Reliability of Target Delineation Using Maximum Intensity Projection in 4-Dimensional Computed Tomography Radiation Therapy Planning

    International Nuclear Information System (INIS)

    Lu, Wei; Neuner, Geoffrey A.; George, Rohini; Wang, Zhendong; Sasor, Sarah; Huang, Xuan; Regine, William F.; Feigenberg, Steven J.; D'Souza, Warren D.

    2014-01-01

    Purpose: To investigate whether coaching patients' breathing would improve the match between ITV MIP (internal target volume generated by contouring in the maximum intensity projection scan) and ITV 10 (generated by combining the gross tumor volumes contoured in 10 phases of a 4-dimensional CT [4DCT] scan). Methods and Materials: Eight patients with a thoracic tumor and 5 patients with an abdominal tumor were included in an institutional review board-approved prospective study. Patients underwent 3 4DCT scans with: (1) free breathing (FB); (2) coaching using audio-visual (AV) biofeedback via the Real-Time Position Management system; and (3) coaching via a spirometer system (Active Breathing Coordinator or ABC). One physician contoured all scans to generate the ITV 10 and ITV MIP . The match between ITV MIP and ITV 10 was quantitatively assessed with volume ratio, centroid distance, root mean squared distance, and overlap/Dice coefficient. We investigated whether coaching (AV or ABC) or uniform expansions (1, 2, 3, or 5 mm) of ITV MIP improved the match. Results: Although both AV and ABC coaching techniques improved frequency reproducibility and ABC improved displacement regularity, neither improved the match between ITV MIP and ITV 10 over FB. On average, ITV MIP underestimated ITV 10 by 19%, 19%, and 21%, with centroid distance of 1.9, 2.3, and 1.7 mm and Dice coefficient of 0.87, 0.86, and 0.88 for FB, AV, and ABC, respectively. Separate analyses indicated a better match for lung cancers or tumors not adjacent to high-intensity tissues. Uniform expansions of ITV MIP did not correct for the mismatch between ITV MIP and ITV 10 . Conclusions: In this pilot study, audio-visual biofeedback did not improve the match between ITV MIP and ITV 10 . In general, ITV MIP should be limited to lung cancers, and modification of ITV MIP in each phase of the 4DCT data set is recommended

  7. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... When the image slices are reassembled by computer software, the result is a very detailed multidimensional view ... Safety Images related to Computed Tomography (CT) - Head Videos related to Computed Tomography (CT) - Head Sponsored by ...

  8. What is Computed Tomography?

    Science.gov (United States)

    ... Imaging Medical X-ray Imaging What is Computed Tomography? Share Tweet Linkedin Pin it More sharing options ... Chest X ray Image back to top Computed Tomography (CT) Although also based on the variable absorption ...

  9. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Stroke Brain Tumors Computer Tomography (CT) Safety During Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - ...

  10. Audio-Visual Biofeedback Does Not Improve the Reliability of Target Delineation Using Maximum Intensity Projection in 4-Dimensional Computed Tomography Radiation Therapy Planning

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei, E-mail: wlu@umm.edu [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland (United States); Neuner, Geoffrey A.; George, Rohini; Wang, Zhendong; Sasor, Sarah [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland (United States); Huang, Xuan [Research and Development, Care Management Department, Johns Hopkins HealthCare LLC, Glen Burnie, Maryland (United States); Regine, William F.; Feigenberg, Steven J.; D' Souza, Warren D. [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland (United States)

    2014-01-01

    Purpose: To investigate whether coaching patients' breathing would improve the match between ITV{sub MIP} (internal target volume generated by contouring in the maximum intensity projection scan) and ITV{sub 10} (generated by combining the gross tumor volumes contoured in 10 phases of a 4-dimensional CT [4DCT] scan). Methods and Materials: Eight patients with a thoracic tumor and 5 patients with an abdominal tumor were included in an institutional review board-approved prospective study. Patients underwent 3 4DCT scans with: (1) free breathing (FB); (2) coaching using audio-visual (AV) biofeedback via the Real-Time Position Management system; and (3) coaching via a spirometer system (Active Breathing Coordinator or ABC). One physician contoured all scans to generate the ITV{sub 10} and ITV{sub MIP}. The match between ITV{sub MIP} and ITV{sub 10} was quantitatively assessed with volume ratio, centroid distance, root mean squared distance, and overlap/Dice coefficient. We investigated whether coaching (AV or ABC) or uniform expansions (1, 2, 3, or 5 mm) of ITV{sub MIP} improved the match. Results: Although both AV and ABC coaching techniques improved frequency reproducibility and ABC improved displacement regularity, neither improved the match between ITV{sub MIP} and ITV{sub 10} over FB. On average, ITV{sub MIP} underestimated ITV{sub 10} by 19%, 19%, and 21%, with centroid distance of 1.9, 2.3, and 1.7 mm and Dice coefficient of 0.87, 0.86, and 0.88 for FB, AV, and ABC, respectively. Separate analyses indicated a better match for lung cancers or tumors not adjacent to high-intensity tissues. Uniform expansions of ITV{sub MIP} did not correct for the mismatch between ITV{sub MIP} and ITV{sub 10}. Conclusions: In this pilot study, audio-visual biofeedback did not improve the match between ITV{sub MIP} and ITV{sub 10}. In general, ITV{sub MIP} should be limited to lung cancers, and modification of ITV{sub MIP} in each phase of the 4DCT data set is recommended.

  11. Review of muon tomography

    International Nuclear Information System (INIS)

    Feng Hanliang; Jiao Xiaojing

    2010-01-01

    As a new detection technology, Muon tomography has some potential benefits, such as being able to form a three- dimensional image, without radiation, low cost, fast detecting etc. Especially, muon tomography will play an important role in detecting nuclear materials. It introduces the theory of Muon tomography, its advantages and the Muon tomography system developed by decision sciences corporation and Los Alamos national laboratory. (authors)

  12. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special x-ray ... What is CT Scanning of the Head? Computed tomography, more commonly known as a CT or CAT ...

  13. Emission computed tomography

    International Nuclear Information System (INIS)

    Ott, R.J.

    1986-01-01

    Emission Computed Tomography is a technique used for producing single or multiple cross-sectional images of the distribution of radionuclide labelled agents in vivo. The techniques of Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) are described with particular regard to the function of the detectors used to produce images and the computer techniques used to build up images. (UK)

  14. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses Computed tomography (CT) of the sinuses uses special x-ray equipment ... story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content ...

  15. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special x-ray equipment ... story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content ...

  16. Positron emission tomography

    International Nuclear Information System (INIS)

    Reivich, M.; Alavi, A.

    1985-01-01

    This book contains 24 selections. Some of the titles are: Positron Emission Tomography Instrumentation, Generator Systems for Positron Emitters, Reconstruction Algorithms, Cerebral Glucose Consumption: Methodology and Validation, Cerebral Blood Flow Tomography Using Xenon-133 Inhalation: Methods and Clinical Applications, PET Studies of Stroke, Cardiac Positron Emission Tomography, and Use of PET in Oncology

  17. OptMAVEn--a new framework for the de novo design of antibody variable region models targeting specific antigen epitopes.

    Directory of Open Access Journals (Sweden)

    Tong Li

    Full Text Available Antibody-based therapeutics provides novel and efficacious treatments for a number of diseases. Traditional experimental approaches for designing therapeutic antibodies rely on raising antibodies against a target antigen in an immunized animal or directed evolution of antibodies with low affinity for the desired antigen. However, these methods remain time consuming, cannot target a specific epitope and do not lead to broad design principles informing other studies. Computational design methods can overcome some of these limitations by using biophysics models to rationally select antibody parts that maximize affinity for a target antigen epitope. This has been addressed to some extend by OptCDR for the design of complementary determining regions. Here, we extend this earlier contribution by addressing the de novo design of a model of the entire antibody variable region against a given antigen epitope while safeguarding for immunogenicity (Optimal Method for Antibody Variable region Engineering, OptMAVEn. OptMAVEn simulates in silico the in vivo steps of antibody generation and evolution, and is capable of capturing the critical structural features responsible for affinity maturation of antibodies. In addition, a humanization procedure was developed and incorporated into OptMAVEn to minimize the potential immunogenicity of the designed antibody models. As case studies, OptMAVEn was applied to design models of neutralizing antibodies targeting influenza hemagglutinin and HIV gp120. For both HA and gp120, novel computational antibody models with numerous interactions with their target epitopes were generated. The observed rates of mutations and types of amino acid changes during in silico affinity maturation are consistent with what has been observed during in vivo affinity maturation. The results demonstrate that OptMAVEn can efficiently generate diverse computational antibody models with both optimized binding affinity to antigens and reduced

  18. Effectiveness of a group opt-in session on uptake and graduation rates for pulmonary rehabilitation.

    Science.gov (United States)

    Graves, J; Sandrey, V; Graves, T; Smith, D L

    2010-08-01

    Pulmonary rehabilitation (PR) is an effective intervention in the treatment of patients with chronic obstructive pulmonary disease (COPD). Unfortunately some patients offered this treatment either fail to take up the offer or fail to complete the course. Studies have indicated a number of factors influencing uptake and completion rates. We describe the introduction of an intervention, the group opt-in session (GOIS), prior to individualised baseline assessment and entry to the PR course, with the intention being to improve uptake and completion rates. A 1.5-hour-long GOIS was offered as the first face-to-face contact to all patients referred for PR. Drop-out rates at all stages of the pathway from referral to graduation were collected on 200 patients prior to the introduction of the GOIS (non-GOIS group) and compared to the first 400 patients following introduction (the GOIS group). Possible independent predictors of course uptake and completion were examined in the GOIS group. The proportion of referred patients taking up the offer of individualised baseline assessment or a GOIS was similar (75% vs. 72.2%, p value not significant [ns]). However, since in the GOIS group the opt-in session preceded the individualised baseline assessment and some patients opted-out, a smaller proportion of referred patients underwent this assessment than in the non-GOIS group (58.7% vs. 75%, p graduated in the GOIS group (87.9% vs. 76.4%, p rates due to illness were similar in both groups (8.5% pre vs. 6.8% post, ns). However, drop-out rates not due to illness were much higher in the non-GOIS group (15.1% vs. 5.3%, p graduation rates at The North Bristol Lung Centre PR Course and reduced wasted assessments. There was no effect on initial uptake. Analysis of the behaviour of patients invited to a GOIS suggested that age, lung function and travel distance were important factors influencing patient choice.

  19. Coupling two iteratives algorithms for density measurements by computerized tomography

    International Nuclear Information System (INIS)

    Silva, L.E.M.C.; Santos, C.A.C.; Borges, J.C.; Frenkel, A.D.B.; Rocha, G.M.

    1986-01-01

    This work develops a study for coupling two iteratives algotithms for density measurements by computerized tomography. Tomographies have been obtained with an automatized prototype, controled by a microcomputer, projected and assembled in the Nuclear Instrumentation Laboratory, at COPPE/UFRJ. Results show a good performance of the tomographic system, and demonstrate the validity of the method of calculus adopted. (Author) [pt

  20. [Application of an OPT model in a paediatric nursing clinical case in primary health care].

    Science.gov (United States)

    Rifà Ros, Rosa; Pérez Pérez, Isabel

    2011-01-01

    This article describes the assessment and nursing diagnostic hypothesis generation on a 10 years old child with a parietal contusion who attended the health care centre with his mother. The health centre is located in a rural area in Catalonia, and a paediatric nurse was placed in charge of the child. In the assessment and the subsequent information analysis, the nurse identified an unhealthy situation for the correct development of the child. The situation required the mother's intervention and a change in her habits and behaviours. For the approach of the case study, the OPT model (Outcome Present-state Testing) by Pesut and Herdman was used. The assessment was made by using Marjory Gordon's Functional Health Patterns assessment, and the NANDA-I nursing diagnoses taxonomy, NOC Outcomes taxonomy and NIC Interventions taxonomy was used for the diagnoses and planning. Copyright © 2010 Elsevier España, S.L. All rights reserved.

  1. Well-being and associated factors among adults in the occupied Palestinian territory (oPt).

    Science.gov (United States)

    Harsha, Nouh; Ziq, Luay; Ghandour, Rula; Giacaman, Rita

    2016-08-30

    The World Health Organization (WHO) incorporated well-being into its definition of health in 1948. The significance given to this concept is due to its role in the assessment of people's quality of life and health. Using the WHO Well-being Index, we estimated well-being among adults and identified selected associated factors in the occupied Palestinian territory (oPt) using data obtained from the National Time Use Survey conducted by the Palestinian Central Bureau of Statistics (PCBS) 2012-2013 on a representative sample of persons living in the West Bank and Gaza Strip. Univariate and bivariate analyses were conducted among participants 18 years old and above. Multivariate analysis (Regression) was performed with factors found significant in cross-tabulations, using SPSS® version 20. Overall, 33.8 % (2395) of respondents reported low levels of well-being (ill-being). Neither age, nor sex, nor region were found significant in regression analysis. People who were married, working 15 h or more, with a higher standard of living, who reported participating in community, cultural, and social events, or in religious activities reported high levels of well-being. Those who reported regularly following the mass media, or living in Palestinian refugee camps reported low levels of wellbeing. Overall, about one-third of adult Palestinians reported low levels of well-being (ill-being), a finding which in itself requires attention. Marriage, employment, high living standards, community participation, and religious activities were found to be protective against ill-being. Further investigations are required to determine additional causes of ill-being in the oPt, taking into consideration the possible effects of chronic exposure to political violence on subjective well-being.

  2. Turbocharging Quantum Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Blume-Kohout, Robin J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Gamble, John King [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Nielsen, Erik [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Maunz, Peter Lukas Wilhelm [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Scholten, Travis L. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Rudinger, Kenneth Michael [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    Quantum tomography is used to characterize quantum operations implemented in quantum information processing (QIP) hardware. Traditionally, state tomography has been used to characterize the quantum state prepared in an initialization procedure, while quantum process tomography is used to characterize dynamical operations on a QIP system. As such, tomography is critical to the development of QIP hardware (since it is necessary both for debugging and validating as-built devices, and its results are used to influence the next generation of devices). But tomography suffers from several critical drawbacks. In this report, we present new research that resolves several of these flaws. We describe a new form of tomography called gate set tomography (GST), which unifies state and process tomography, avoids prior methods critical reliance on precalibrated operations that are not generally available, and can achieve unprecedented accuracies. We report on theory and experimental development of adaptive tomography protocols that achieve far higher fidelity in state reconstruction than non-adaptive methods. Finally, we present a new theoretical and experimental analysis of process tomography on multispin systems, and demonstrate how to more effectively detect and characterize quantum noise using carefully tailored ensembles of input states.

  3. 40 CFR 97.288 - CAIR SO2 allowance allocations to CAIR SO2 opt-in units.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR SO2 allowance allocations to CAIR SO2 opt-in units. 97.288 Section 97.288 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) FEDERAL NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS...

  4. 40 CFR 96.288 - CAIR SO2 allowance allocations to CAIR SO2 opt-in units.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false CAIR SO2 allowance allocations to CAIR SO2 opt-in units. 96.288 Section 96.288 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR...

  5. A voluntary deductible in health insurance: the more years you opt for it, the lower your premium?

    NARCIS (Netherlands)

    K.P.M. Winssen van (Kayleigh); R.C. van Kleef (Richard); W.P.M.M. van de Ven (Wynand)

    2017-01-01

    textabstractAdverse selection regarding a voluntary deductible (VD) in health insurance implies that insured only opt for a VD if they expect no (or few) healthcare expenses. This paper investigates two potential strategies to reduce adverse selection: (1) differentiating the premium to the duration

  6. How to opt into the Common European Sales Law? Brief comments on the Commission's proposal for a regulation

    NARCIS (Netherlands)

    Hesselink, M.

    2012-01-01

    Unlike the actual text for the proposed Common European Sales Law (CESL), which is based on extensive preparatory work by academics, the regime for opting into the instrument, which is set out in the main text of the proposed regulation, is entirely of the European Commission's own making. The

  7. How to opt into the Common European Sales Law? Brief comments on the Commission's proposal for a regulation

    NARCIS (Netherlands)

    Hesselink, M.W.; Claeys, I.; Feltkamp, R.

    2013-01-01

    Unlike the actual text for the proposed Common European Sales Law (CESL), which is based on extensive preparatory work by academics, the regime for opting into the instrument, which is set out in the main text of the proposed regulation, is entirely of the European Commission's own making. The

  8. Opt-Out Panel Testing for HIV, Hepatitis B and Hepatitis C in an Urban Emergency Department: A Pilot Study.

    LENUS (Irish Health Repository)

    O'Connell, Sarah

    2016-01-01

    Studies suggest 2 per 1000 people in Dublin are living with HIV, the level above which universal screening is advised. We aimed to assess the feasibility and acceptability of a universal opt-out HIV, Hepatitis B and Hepatitis C testing programme for Emergency Department patients and to describe the incidence and prevalence of blood-borne viruses in this population.

  9. Opting For Families: Recent Trends in the Fertility of Highly Educated Women. NBER Working Paper No. 15074

    Science.gov (United States)

    Shang, Qingyan; Weinberg, Bruce A.

    2009-01-01

    Observers have argued about whether highly-educated women are opting out of their careers and for families. If so, it is natural to expect fertility to increase and, insofar as children are associated with lower employment, further declines in employment. This paper provides a comprehensive study of recent trends in the fertility of…

  10. Electrical Impedance Tomography Technology (EITT) Project

    Science.gov (United States)

    Oliva-Buisson, Yvette J.

    2014-01-01

    Development of a portable, lightweight device providing two-dimensional tomographic imaging of the human body using impedance mapping. This technology can be developed to evaluate health risks and provide appropriate medical care on the ISS, during space travel and on the ground.

  11. Opting out of the peaceful use of nuclear power in Germany. A promising special approach in the European context?

    International Nuclear Information System (INIS)

    Buedenbender, Martin

    2009-01-01

    Nuclear power is in the focus of politics and public attention in Germany not only because of the federal elections. Again and again, voices are heard which doubt the decision taken in 2000 to opt out of the use of nuclear power. The change in parliamentary majority in favor of the alliance of CDU/CSU and FDP as a result of the elections on September 27 is leading to another review of the opt-out decision, as the three parties in their platforms expressed themselves in favor of extending nuclear power plant life. This makes a stocktaking exercise of all salient arguments imperative at the present juncture. The perspective in that case should not be restricted to national aspects but include especially the influence of the European dimension of the subject. Present political positions in the 27 EU countries indicate a renaissance of nuclear power. Numerous countries, such as Italy, Sweden, Poland or the United Kingdom, revoked their historic opt-out decisions, are using nuclear power for the first time, or want to expand greatly the nuclear share in their electricity generation mix. All 3 European agencies with clear majorities advocate the extensive use of nuclear power as a long-term component of the mix of energy resources. Germany, with its decision to opt out of the use of nuclear power, is part of a minority. Being part of a European electricity market which will grow together more and more closely up to complete integration, Germany will always be supplied electricity from nuclear sources in the long run. This will be true irrespective of nuclear power plants being operated in the country. So, shutting down German nuclear power plants will not achieve the goals of nuclear opponents but merely give rise to additional challenges in power technology in an effort to ensure Germany's electricity supply. For this reason, the new German federal government should revoke the decision to opt out of the peaceful use of nuclear power. (orig.)

  12. Recent progress in plasma tomography at JET

    Czech Academy of Sciences Publication Activity Database

    Mlynář, Jan; Bielecki, J.; Craciunescu, T.; Ficker, Ondřej; Imríšek, Martin; Löffelmann, Viktor; Tomeš, Matěj; Alper, B.; Giacomelli, L.; Milocco, A.; Popovichev, S.; Schlummer, T.

    2016-01-01

    Roč. 3, č. 3 (2016), s. 26 ISSN 2336-2626. [SPPT 2016 - 27th Symposium on Plasma Physics and Technology/27./. Prague, 20.06.2016-23.06.2016] R&D Projects: GA MŠk LG14002 Institutional support: RVO:61389021 Keywords : tomography * JET * SXR * neutron * RE Subject RIV: BL - Plasma and Gas Discharge Physics

  13. Inter laboratory comparison on Industrial Computed Tomography

    DEFF Research Database (Denmark)

    Angel, Jais Andreas Breusch; De Chiffre, Leonardo

    An interlaboratory comparison on industrial X-ray Computed Tomography (CT) was organized by the Centre for Geometrical Metrology (CGM), Department of Mechanical Engineering, Technical University of Denmark (DTU) and carried out within the project “Centre for Industrial Application of CT scanning...

  14. Computed tomography for radiographers

    International Nuclear Information System (INIS)

    Brooker, M.

    1986-01-01

    Computed tomography is regarded by many as a complicated union of sophisticated x-ray equipment and computer technology. This book overcomes these complexities. The rigid technicalities of the machinery and the clinical aspects of computed tomography are discussed including the preparation of patients, both physically and mentally, for scanning. Furthermore, the author also explains how to set up and run a computed tomography department, including advice on how the room should be designed

  15. Single photon emission tomography

    International Nuclear Information System (INIS)

    Buvat, Irene

    2011-09-01

    The objective of this lecture is to present the single photon emission computed tomography (SPECT) imaging technique. Content: 1 - Introduction: anatomic, functional and molecular imaging; Principle and role of functional or molecular imaging; 2 - Radiotracers: chemical and physical constraints, main emitters, radioisotopes production, emitters type and imaging techniques; 3 - Single photon emission computed tomography: gamma cameras and their components, gamma camera specifications, planar single photon imaging characteristics, gamma camera and tomography; 4 - Quantification in single photon emission tomography: attenuation, scattering, un-stationary spatial resolution, partial volume effect, movements, others; 5 - Synthesis and conclusion

  16. Multiphoton tomography of astronauts

    Science.gov (United States)

    König, Karsten; Weinigel, Martin; Pietruszka, Anna; Bückle, Rainer; Gerlach, Nicole; Heinrich, Ulrike

    2015-03-01

    Weightlessness may impair the astronaut's health conditions. Skin impairments belong to the most frequent health problems during space missions. Within the Skin B project, skin physiological changes during long duration space flights are currently investigated on three European astronauts that work for nearly half a year at the ISS. Measurements on the hydration, the transepidermal water loss, the surface structure, elasticity and the tissue density by ultrasound are conducted. Furthermore, high-resolution in vivo histology is performed by multiphoton tomography with 300 nm spatial and 200 ps temporal resolution. The mobile certified medical tomograph with a flexible 360° scan head attached to a mechano-optical arm is employed to measure two-photon autofluorescence and SHG in the volar forearm of the astronauts. Modification of the tissue architecture and of the fluorescent biomolecules NAD(P)H, keratin, melanin and elastin are detected as well as of SHG-active collagen. Thinning of the vital epidermis, a decrease of the autofluoresence intensity, an increase in the long fluorescence lifetime, and a reduced skin ageing index SAAID based on an increased collagen level in the upper dermis have been found. Current studies focus on recovery effects.

  17. Feasibility study for mega-electron-volt electron beam tomography.

    Science.gov (United States)

    Hampel, U; Bärtling, Y; Hoppe, D; Kuksanov, N; Fadeev, S; Salimov, R

    2012-09-01

    Electron beam tomography is a promising imaging modality for the study of fast technical processes. But for many technical objects of interest x rays of several hundreds of keV energy are required to achieve sufficient material penetration. In this article we report on a feasibility study for fast electron beam computed tomography with a 1 MeV electron beam. The experimental setup comprises an electrostatic accelerator with beam optics, transmission target, and a single x-ray detector. We employed an inverse fan-beam tomography approach with radiographic projections being generated from the linearly moving x-ray source. Angular projections were obtained by rotating the object.

  18. Feasible Dose Reduction in Routine Chest Computed Tomography Maintaining Constant Image Quality Using the Last Three Scanner Generations: From Filtered Back Projection to Sinogram-affirmed Iterative Reconstruction and Impact of the Novel Fully Integrated Detector Design Minimizing Electronic Noise

    Directory of Open Access Journals (Sweden)

    Lukas Ebner

    2014-01-01

    Full Text Available Objective:The aim of the present study was to evaluate a dose reduction in contrast-enhanced chest computed tomography (CT by comparing the three latest generations of Siemens CT scanners used in clinical practice. We analyzed the amount of radiation used with filtered back projection (FBP and an iterative reconstruction (IR algorithm to yield the same image quality. Furthermore, the influence on the radiation dose of the most recent integrated circuit detector (ICD; Stellar detector, Siemens Healthcare, Erlangen, Germany was investigated. Materials and Methods: 136 Patients were included. Scan parameters were set to a thorax routine: SOMATOM Sensation 64 (FBP, SOMATOM Definition Flash (IR, and SOMATOM Definition Edge (ICD and IR. Tube current was set constantly to the reference level of 100 mA automated tube current modulation using reference milliamperes. Care kV was used on the Flash and Edge scanner, while tube potential was individually selected between 100 and 140 kVp by the medical technologists at the SOMATOM Sensation. Quality assessment was performed on soft-tissue kernel reconstruction. Dose was represented by the dose length product. Results: Dose-length product (DLP with FBP for the average chest CT was 308 mGycm ± 99.6. In contrast, the DLP for the chest CT with IR algorithm was 196.8 mGycm ± 68.8 (P = 0.0001. Further decline in dose can be noted with IR and the ICD: DLP: 166.4 mGycm ± 54.5 (P = 0.033. The dose reduction compared to FBP was 36.1% with IR and 45.6% with IR/ICD. Signal-to-noise ratio (SNR was favorable in the aorta, bone, and soft tissue for IR/ICD in combination compared to FBP (the P values ranged from 0.003 to 0.048. Overall contrast-to-noise ratio (CNR improved with declining DLP. Conclusion: The most recent technical developments, namely IR in combination with integrated circuit detectors, can significantly lower radiation dose in chest CT examinations.

  19. Borehole radar diffraction tomography

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seong Jun; Kim, Jung Ho; Yi, Myeong Jong; Chung, Seung Hwan; Lee, Hee Il [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

    1997-12-01

    Tomography is widely used as imaging method for determining subsurface structure. Among the reconstruction algorithms for tomographic imaging, travel time tomography is almost applied to imaging subsurface. But isolated small body comparable with the wavelength could not be well recognized by travel time tomography. Other tomographic method are need to improve the imaging process. In the study of this year, diffraction tomography was investigated. The theory for diffraction tomography is based on the 1st-order Born approximation. Multisource holography, which is similar to Kirchihoff migration, is compared with diffraction tomography. To improve 1st-order Born diffraction tomography, two kinds of filter designed from multisource holography and 2-D green function, respectively, applied on the reconstructed image. The algorithm was tested for the numerical modeling data of which algorithm consists of the analytic computation of radar signal in transmitter and receiver regions and 2-D FDM scheme for the propagation of electromagnetic waves in media. The air-filled cavity model to show a typical diffraction pattern was applied to diffraction tomography imaging, and the result shows accurate location and area of cavity. But the calculated object function is not well matched the real object function, because the air-filled cavity model is not satisfied week scattered inhomogeneity for 1st born approximation, and the error term is included in estimating source wavelet from received signals. In spite of the object function error, the diffraction tomography assist for interpretation of subsurface as if conducted with travel time tomography. And the fracture model was tested, 1st born diffraction tomographic image is poor because of limited view angle coverage and violation of week scatter assumption, but the filtered image resolve the fracture somewhat better. The tested diffraction tomography image confirms effectiveness of filter for enhancing resolution. (author). 14

  20. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is a fast, painless exam that uses special ... the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT ...

  1. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) ... are the limitations of Children's CT? What is Children's CT? Computed tomography, more commonly known as a ...

  2. Gamma tomography apparatus

    International Nuclear Information System (INIS)

    Span, F.J.

    1988-01-01

    The patent concerns a gamma tomography apparatus for medical diagnosis. The apparatus comprises a gamma scintillation camera head and a suspension system for supporting and positioning the camera head with respect for the patient. Both total body scanning and single photon emission tomography can be carried out with the apparatus. (U.K.)

  3. Emission computed tomography

    International Nuclear Information System (INIS)

    Budinger, T.F.; Gullberg, G.T.; Huesman, R.H.

    1979-01-01

    This chapter is devoted to the methods of computer assisted tomography for determination of the three-dimensional distribution of gamma-emitting radionuclides in the human body. The major applications of emission computed tomography are in biological research and medical diagnostic procedures. The objectives of these procedures are to make quantitative measurements of in vivo biochemical and hemodynamic functions

  4. Tomography of nonclassical states

    NARCIS (Netherlands)

    Bazrafkan, MR; Man'ko, [No Value

    2003-01-01

    A review of the symplectic tomography method is presented. Superpositions of different types of photon states are considered within the framework of the tomography approach. Such nonclassical photon states as even and odd coherent states, crystallized Schrodinger cat states, and other superposition

  5. Efficacy and safety of fidaxomicin compared with oral vancomycin for the treatment of adults with Clostridium difficile-associated diarrhea: data from the OPT-80-003 and OPT-80-004 studies.

    Science.gov (United States)

    Chen, Luke F; Anderson, Deverick J

    2012-06-01

    Clostridium difficile is emerging as one of the most important and devastating pathogens affecting hospitalized populations around the world. The incidence of C. difficile infection is increasing and disease severity is worsening. Thus, an effective alternative to metronidazole and oral vancomycin is urgently needed. Two Phase III trials, OPT-80-003 and OPT-80-004, showed that oral fidaxomicin for 10 days was noninferior compared with treatment with oral vancomycin among adult patients with toxin-positive C. difficile-associated diarrhea (CDAD). Furthermore, fidaxomicin was associated with a lower rate of recurrence of CDAD within 4 weeks of completion of therapy. The safety and tolerability of fidaxomicin was consistent with earlier studies and established that fidaxomicin is an efficacious and well-tolerated treatment option for CDAD. Despite these potential advantages, the cost-effectiveness of this expensive agent remains poorly understood.

  6. Measuring techniques in emission computed tomography

    International Nuclear Information System (INIS)

    Jordan, K.; Knoop, B.

    1988-01-01

    The chapter reviews the historical development of the emission computed tomography and its basic principles, proceeds to SPECT and PET, special techniques of emission tomography, and concludes with a comprehensive discussion of the mathematical fundamentals of the reconstruction and the quantitative activity determination in vivo, dealing with radon transformation and the projection slice theorem, methods of image reconstruction such as analytical and algebraic methods, limiting conditions in real systems such as limited number of measured data, noise enhancement, absorption, stray radiation, and random coincidence. (orig./HP) With 111 figs., 6 tabs [de

  7. Development of Hardware Dual Modality Tomography System

    Directory of Open Access Journals (Sweden)

    R. M. Zain

    2009-06-01

    Full Text Available The paper describes the hardware development and performance of the Dual Modality Tomography (DMT system. DMT consists of optical and capacitance sensors. The optical sensors consist of 16 LEDs and 16 photodiodes. The Electrical Capacitance Tomography (ECT electrode design use eight electrode plates as the detecting sensor. The digital timing and the control unit have been developing in order to control the light projection of optical emitters, switching the capacitance electrodes and to synchronize the operation of data acquisition. As a result, the developed system is able to provide a maximum 529 set data per second received from the signal conditioning circuit to the computer.

  8. Project DEGRUPE: Goals and Historiographical Contextualization

    Directory of Open Access Journals (Sweden)

    COELHO, Maria Helena da Cruz

    2015-07-01

    Full Text Available This paper aims to present the main axes of the project DEGRUPE whose principal objective is to study the role of the clergy in the construction of the Iberian monarchies and mobility circuits designed by these protagonists. To fulfill this objective, the interuniversity project team of DEGRUPE opted for a comparative perspective between different kingdoms of the Iberian Peninsula. The second part of this paper consists of a brief analysis of the underlying historiographical framework of the project including mainly research on relationship between clergy and royalty in the middle ages.

  9. Cardiac blood pool emission tomography

    International Nuclear Information System (INIS)

    Itti, R.; Philippe, L.; Lorgeron, J.M.; Charbonnier, B.; Raynaud, P.; Brochier, M.

    1983-01-01

    After blood pool labeling using technetium-99m, a series of cardiac pictures is acquired during the rotation of a gamma-camera about the patient. Computer processing leads to reconstruction of various tomographic slices from the original planar projection. Electrocardiographic gating selects the different phases of the cardiac cycle. Individual slices through the left ventricular region are added in order to provide ''thick'' slices on which global and regional parameters of the left ventricular function can be determined. Due to the proportionality existing between count rates and labeled blood volumes, any geometrical model can be avoided. The delineation of regions of interest for count integration is made easier due to the absence of superimposition of structures; no correction for background is necessary. Tomography thus appears to be more consistent and more accurate than the classical methods using planar projections. In addition, right ventricular morphological and kinetic studies can be performed in the same conditions as for the left ventricle [fr

  10. Domestic uptake of green energy promoted by opt-out tariffs

    Science.gov (United States)

    Ebeling, Felix; Lotz, Sebastian

    2015-09-01

    Motivating individuals to choose energy from sustainable sources over conventionally produced power constitutes one of the biggest policy challenges for societies. Here we present the results of a randomized controlled trial in Germany that tested the impact of default rules (that is, a type of `nudging’) on voluntary purchases of `green’ energy contracts that entirely stem from renewable resources. Setting the default choice to more expensive `green’ energy (that is, where consumers have to actively opt out if they do not want it) increased purchases of such nearly tenfold. Furthermore, county-level political preference for the green party uniquely predicted behaviour in the absence of the nudge, suggesting that default setting potentially overrules motivational aspects of green energy purchases. In follow-up experiments, we provide further evidence that the effect does not seem to be driven by unawareness. Summarizing, the present research provides an example of using behavioural science for climate change mitigation and shows alternatives to the use of subsidies or other economic incentives.

  11. Adaptations of energy metabolism during cerebellar neurogenesis are co-opted in medulloblastoma.

    Science.gov (United States)

    Tech, Katherine; Deshmukh, Mohanish; Gershon, Timothy R

    2015-01-28

    Recent studies show that metabolic patterns typical of cancer cells, including aerobic glycolysis and increased lipogenesis, are not unique to malignancy, but rather originate in physiologic development. In the postnatal brain, where sufficient oxygen for energy metabolism is scrupulously maintained, neural progenitors nevertheless metabolize glucose to lactate and prioritize lipid synthesis over fatty acid oxidation. Medulloblastoma, a cancer of neural progenitors that is the most common malignant brain tumor in children, recapitulates the metabolic phenotype of brain progenitor cells. During the physiologic proliferation of neural progenitors, metabolic enzymes generally associated with malignancy, including Hexokinase 2 (Hk2) and Pyruvate kinase M2 (PkM2) configure energy metabolism to support growth. In these non-malignant cells, expression of Hk2 and PkM2 is driven by transcriptional regulators that are typically identified as oncogenes, including N-myc. Importantly, N-myc continues to drive Hk2 and PkM2 in medulloblastoma. Similarly E2F transcription factors and PPARγ function in both progenitors and medulloblastoma to optimize energy metabolism to support proliferation. These findings show that the "metabolic transformation" that is a hallmark of cancer is not specifically limited to cancer. Rather, metabolic transformation represents a co-opting of developmental programs integral to physiologic growth. Despite their physiologic origins, the molecular mechanisms that mediate metabolic transformation may nevertheless present ideal targets for novel anti-tumor therapy. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Limited angle STIM and PIXE tomography of single cells

    International Nuclear Information System (INIS)

    Andrea, T.; Rothermel, M.; Werner, R.; Butz, T.; Reinert, T.

    2010-01-01

    STIM (scanning transmission ion microscopy) tomography has been shown to be a valuable method for the three-dimensional characterization of microsamples. It has, however, rarely been employed for the study of single cells, since a free-standing sample is needed for an ordinary tomography experiment. This requirement places high demands on sample preparation techniques. In this study cells fixated on a substrate rather than free-standing were used for tomography. Since the substrate prevented a full rotation of the sample an algorithm for limited-angle tomography was devised. STIM projections covering only a limited angular range of ca. 120 o were supplemented with simulated projections generated from a back and forth iteration between real space and Radon space. The energy loss caused by the substrate was subtracted from each projection. The cells were reconstructed using filtered backprojection. The surface of the cells as well as some interior structures could be reconstructed. Following the STIM projections a lesser number of PIXE (particle induced X-ray emission) projections were taken in order to obtain information about the elemental distribution of the sample. From the PIXE projections the three-dimensional phosphorus distribution within the cell was reconstructed using limited-angle tomography. Superimposition of the STIM and PIXE tomograms revealed the location of intracellular structures. Whereas STIM tomography is sensitive to density contrast, which are greatest at the surface, PIXE tomography is sensitive to changes in elemental concentration. Hence, the combination of the two methods can be very fruitful, while the limited angle approach can compensate some of the difficulties associated with tomography of single cells, namely preparation difficulties and excessive sample damage.

  13. Victims, vectors and villains: are those who opt out of vaccination morally responsible for the deaths of others?

    Science.gov (United States)

    Jamrozik, Euzebiusz; Handfield, Toby; Selgelid, Michael J

    2016-12-01

    Mass vaccination has been a successful public health strategy for many contagious diseases. The immunity of the vaccinated also protects others who cannot be safely or effectively vaccinated-including infants and the immunosuppressed. When vaccination rates fall, diseases like measles can rapidly resurge in a population. Those who cannot be vaccinated for medical reasons are at the highest risk of severe disease and death. They thus may bear the burden of others' freedom to opt out of vaccination. It is often asked whether it is legitimate for states to adopt and enforce mandatory universal vaccination. Yet this neglects a related question: are those who opt out, where it is permitted, morally responsible when others are harmed or die as a result of their decision? In this article, we argue that individuals who opt out of vaccination are morally responsible for resultant harms to others. Using measles as our main example, we demonstrate the ways in which opting out of vaccination can result in a significant risk of harm and death to others, especially infants and the immunosuppressed. We argue that imposing these risks without good justification is blameworthy and examine ways of reaching a coherent understanding of individual moral responsibility for harms in the context of the collective action required for disease transmission. Finally, we consider several objections to this view, provide counterarguments and suggest morally permissible alternatives to mandatory universal vaccination including controlled infection, self-imposed social isolation and financial penalties for refusal to vaccinate. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  14. Factors influencing patients with stage 5 chronic kidney disease to opt for conservative management: a practitioner research study

    OpenAIRE

    Johnston, Sheila; Noble, Helen

    2012-01-01

    Aims and objectives. This study explored decision-making experiences of patients with stage 5 chronic kidney disease when opting for conservative management of their renal failure.Background. Dialysis is an invasive treatment, and for some older patients, there is an associated treatment burden of dialysis-related symptoms. An alternative choice is conservative management, but little is known about those who make this decision and how they are supported through the process.Design. Qualitative...

  15. Modeling Atom Probe Tomography: A review

    Energy Technology Data Exchange (ETDEWEB)

    Vurpillot, F., E-mail: francois.vurpillot@univ-rouen.fr [Groupe de Physique des Matériaux, UMR CNRS 6634, Université de Rouen, Saint Etienne du Rouvray 76801 (France); Oberdorfer, C. [Institut für Materialwissenschaft, Lehrstuhl für Materialphysik, Universität Stuttgart, Heisenbergstr. 3, 70569 Stuttgart (Germany)

    2015-12-15

    Improving both the precision and the accuracy of Atom Probe Tomography reconstruction requires a correct understanding of the imaging process. In this aim, numerical modeling approaches have been developed for 15 years. The injected ingredients of these modeling tools are related to the basic physic of the field evaporation mechanism. The interplay between the sample nature and structure of the analyzed sample and the reconstructed image artefacts have pushed to gradually improve and make the model more and more sophisticated. This paper reviews the evolution of the modeling approach in Atom Probe Tomography and presents some future potential directions in order to improve the method. - Highlights: • The basics of field evaporation. • The main aspects of Atom Probe Tomography modeling. • The intrinsic limitations of the current method and future potential directions to improve the understanding of tip to image ion projection.

  16. Computerised Axial Tomography (CAT)

    Science.gov (United States)

    1990-06-01

    Ministry of’ Defence, Defence Research Information Centre, UK. Computerised Axial Tomography ( CAT ) Report Secufty C"uMiauion tide Onadtiicadon (U. R, Cor S...DRIC T 8485 COMPUTERISED AXIAL TOMOGRAPHY ( CAT ) F.P. GENTILE, F. SABETTA, V. TRO1* ISS R 78/4.Rome, 1.5 Mlarch 1978 (from Italian) B Distribution(f...dello Radiazioni ISSN 0390--6477 F.P. GENTILE, F. SABETTA. V. TROI Computerised Axial Tomography ( CAT ) March 15, 1978). This paper is a review of

  17. Quantification in emission tomography

    International Nuclear Information System (INIS)

    Buvat, Irene

    2011-11-01

    The objective of this lecture is to understand the possibilities and limitations of the quantitative analysis of single photon emission computed tomography (SPECT) and positron emission tomography (PET) images. It is also to identify the conditions to be fulfilled to obtain reliable quantitative measurements from images. Content: 1 - Introduction: Quantification in emission tomography - definition and challenges; quantification biasing phenomena 2 - Main problems impacting quantification in PET and SPECT: problems, consequences, correction methods, results (Attenuation, scattering, partial volume effect, movement, un-stationary spatial resolution in SPECT, fortuitous coincidences in PET, standardisation in PET); 3 - Synthesis: accessible efficiency, know-how, Precautions, beyond the activity measurement

  18. Positron emission tomography

    International Nuclear Information System (INIS)

    Wienhard, K.; Heiss, W.D.

    1984-01-01

    The principles and selected clinical applications of positron emission tomography are described. In this technique a chemical compound is labeled with a positron emitting isotope and its biochemical pathway is traced by coincidence detection of the two annihilation photons. The application of the techniques of computed tomography allows to reconstruct the spatial distribution of the radioactivity within a subject. The 18 F-deoxyglucose method for quantitative measurement of local glucose metabolism is discussed in order to illustrate the possibilities of positron emission tomography to record physiological processes in vivo. (orig.) [de

  19. Single photon emission computerized tomography (SPECT)

    International Nuclear Information System (INIS)

    Ganatra, R.D.

    1992-01-01

    Tomography in nuclear medicine did not originate after the introduction of X-ray computerized tomography (CT). Even in the days of rectilinear scanner, tomography was attempted with multiple detector heads rotating around the patient, but the counts at each plane were never very high to obtain a satisfactory image. A high resolution focusing collimator can look at different depths but taking several slices in one projection was a time consuming process. Rectilinear scanners lose lot of counts in the collimator to look at one point, at on time, in one plane. It is true that attempts to do tomography with gamma camera really got a boost after the success of CT. By that time, algorithms for doing reconstruction of images also were highly refined and for advanced. Clinical application of SPECT has become widespread now, because of the development of suitable radiopharmaceuticals and improvement in instrumentation. The SPECT provides a direct measure of regional organ function and is performed with nuclides such as 123 I and 99 Tc m that emit a mono-image photon during their decay. SPECT is far less expensive than positron emission tomography

  20. Single photon emission computerized tomography (SPECT)

    Energy Technology Data Exchange (ETDEWEB)

    Ganatra, R D

    1993-12-31

    Tomography in nuclear medicine did not originate after the introduction of X-ray computerized tomography (CT). Even in the days of rectilinear scanner, tomography was attempted with multiple detector heads rotating around the patient, but the counts at each plane were never very high to obtain a satisfactory image. A high resolution focusing collimator can look at different depths but taking several slices in one projection was a time consuming process. Rectilinear scanners lose lot of counts in the collimator to look at one point, at on time, in one plane. It is true that attempts to do tomography with gamma camera really got a boost after the success of CT. By that time, algorithms for doing reconstruction of images also were highly refined and for advanced. Clinical application of SPECT has become widespread now, because of the development of suitable radiopharmaceuticals and improvement in instrumentation. The SPECT provides a direct measure of regional organ function and is performed with nuclides such as {sup 123}I and {sup 99}Tc{sup m} that emit a mono-image photon during their decay. SPECT is far less expensive than positron emission tomography

  1. Four generations in a family with neurofibromatosis 1: precocious puberty and optic nerve tumor (OPT).

    Science.gov (United States)

    Gucev, Z; Krstevska-Konstantinova, M; Tasic, V; Jancevska, A; Kirovski, I; Pop-Jordanova, N

    2010-01-01

    Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with varied clinical manifestations. The proband is a 6-year-old boy with signs of precocious puberty. His penis was 10 cm, testicles 8 ml, pubic hair P2-3, and the genital skin was hyperpigmented. Multiple cafe au lait spots well above 5 mm were noticeable on his skin, as well as hard subcutaneous nodules, mostly on his trunk. His intelligence and hearing are normal. He has no history of seizures. Laboratory analysis showed: LH LH 1.4 mIU/ml, FSH 6.2 mIU/ml, testosterone 183 ng/ml. Bone age was 9 years. LHRH stimulation was characteristic of true precocious puberty (LH 9.8 mIU/ml and FSH 8.9 mIU/ml after 30 minutes). The MRI of the brain showed a tumor of the suprasellar region with compression of the pituitary stalk. At present the boy is 6 years old and has been treated with triptoreline acetate for 3 months. The volume of the testicles has decreased to 7 ml and a slight loss of pubic hair was noted. In addition, his mother and his grandfather exhibited dermal masses, and focal cutaneous and subcutaneous growths. The great-grand father had had the same cutaneous changes and died at the age of 75 from unrelated causes. It has already been well documented that NF is associated with an increased risk of malignancy and precocious puberty. Hence, we emphasize the need for a close and regular clinical follow-up of the OPT, puberty and patterns of growth.

  2. Prevalence and factors associated with sexually transmitted infections among HIV positive women opting for intrauterine contraception.

    Directory of Open Access Journals (Sweden)

    Othman Kakaire

    Full Text Available Women living with HIV/AIDS (WLHA are a high risk group for sexually transmitted infections (STIs. However, the majority of women with STIs are asymptomatic. Data on prevalence of STIs among WLHA in Uganda are limited. The objective of the study was to determine prevalence and factors associated with STIs among WLHA opting for intrauterine contraceptive device (IUD.Three hundred fifty one WLHA deemed free of STIs using a syndromic logarithm were enrolled into the study. Endo-cervical swabs were taken before IUD insertion and PCR test for Nisseria gonorrhea (NG, Trichomonas vaginalis (TV and Chlamydia trachomatis (CT infections conducted.Participants' mean age was 29.4 ± 6.2 years, 83% were under 35years, 50% had secondary education and 73% were married. The majority (69% had disclosed their HIV sero status to their spouses, 82% used Cotrimoxazole prophylaxis, 70% were on antiretroviral therapy, 90% had CD4 count greater than 350, about 60% reported condoms use and 70% were of parity 2-4. Over 50% of the participants' spouses were older than 35 years and 72% had attained secondary education. STIs prevalence was 11.1%, (95% CI 7.8-14.4 and individual prevalence for TV, NG, and CT was 5.9%, 5.4% and 0.9% respectively. Factors independently associated with STI were having primary or less education (OR= 2.3, 95% CI: 1.09 - 4.85 having a spouse of primary or less education (OR= 3.3, 95% CI: 1.6 - 6.78 and muslim faith (OR= 0.2, 95% CI: 0.04 - 0.78.STI prevalence was 11.1%. TV and NG were the commonest STIs in this population. Having primary or less education for both participant and spouse was associated with increased risk while being of muslim faith was associated with reduced risk of STI.

  3. A 10-year population based study of 'opt-out' HIV testing of tuberculosis patients in Alberta, Canada: national implications.

    Directory of Open Access Journals (Sweden)

    Richard Long

    Full Text Available Compliance with the recommendation that all tuberculosis (TB patients be tested for human immunodeficiency virus (HIV has not yet been achieved in Canada or globally.The experience of "opt-out" HIV testing of TB patients in the Province of Alberta, Canada is described over a 10-year period, 2003-2012. Testing rates are reported before and after the introduction of the "opt-out" approach. Risk factors for HIV seropositivity are described and demographic, clinical and laboratory characteristics of TB patients who were newly diagnosed versus previously diagnosed with HIV are compared. Genotypic clusters, defined as groups of two or more cases whose isolates of Mycobacterium tuberculosis had identical DNA fingerprints over the 10-year period or within 2 years of one another, were analyzed for their ability to predict HIV co-infection.HIV testing rates were 26% before and 90% after the introduction of "opt-out" testing. During the "opt-out" testing years those 64 years of age at diagnosis were less likely to have been tested. In those tested the prevalence of HIV was 5.6%. In the age group 15-64 years, risk factors for HIV were: age (35-64 years, Canadian-born Aboriginal or foreign-born sub-Saharan African origin, and combined respiratory and non-respiratory disease. Compared to TB patients previously known to be HIV positive, TB patients newly discovered to be HIV positive had more advanced HIV disease (lower CD4 counts; higher viral loads at diagnosis. Large cluster size was associated with Aboriginal ancestry. Cluster size predicted HIV co-infection in Aboriginal peoples when clusters included all cases reported over 10 years but not when clusters included cases reported within 2 years of one another."Opt-out" HIV testing of TB patients is effective and well received. Universal HIV testing of TB patients (>80% of patients tested has immediate (patients and longer-term (TB/HIV program planning benefits.

  4. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... tomography (CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. ...

  5. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... tomography (CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. ...

  6. Cardiac positron emission tomography

    International Nuclear Information System (INIS)

    Eftekhari, M.; Ejmalian, G.

    2003-01-01

    Positron emission tomography is an intrinsically tool that provide a unique and unparalleled approach for clinicians and researchers to interrogate the heart noninvasively. The ability to label substances of physiological interest with positron-emitting radioisotopes has permitted insight into normal blood flow and metabolism and the alterations that occur with disease states. Positron emission tomography of the heart has evolved as a unique, noninvasive approach for the assessment of myocardial perfusion, metabolism, and function. Because of the intrinsic quantitative nature of positron emission tomography measurements as well as the diverse compounds that can be labeled with positron- emitting radioisotopes, studies with positron emission tomography have provided rich insight into the physiology of the heart under diverse conditions

  7. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... for Brain Tumors Radiation Therapy for Head and Neck Cancer Others American Stroke Association National Stroke Association ... Computer Tomography (CT) Safety During Pregnancy Head and Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine ...

  8. Positron emission tomography

    International Nuclear Information System (INIS)

    Iio, Masahiro

    1982-01-01

    Utilization of positron emission tomography was reviewed in relation to construction and planned construction of small-size medical cyclotrons, planned construction of positron cameras and utilization of short-lived radionuclides. (Chiba, N.)

  9. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - ...

  10. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ... Neck Cancer X-ray, Interventional Radiology and Nuclear Medicine Radiation Safety Images related to Computed Tomography (CT) - ...

  11. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Brain Tumors Radiation Therapy for ... Tomography (CT) - Head Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  12. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top ... Tomography (CT) - Sinuses Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  13. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... are the limitations of CT of the Sinuses? What is CT (Computed Tomography) of the Sinuses? Computed ... nasal cavity by small openings. top of page What are some common uses of the procedure? CT ...

  14. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... the limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, ... than regular radiographs (x-rays). top of page What are some common uses of the procedure? CT ...

  15. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... of the Head? Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic ... white on the x-ray; soft tissue, such as organs like the heart or liver, shows up ...

  16. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... of the Sinuses? Computed tomography, more commonly known as a CT or CAT scan, is a diagnostic ... white on the x-ray; soft tissue, such as organs like the heart or liver, shows up ...

  17. Intracoronary optical coherence tomography

    DEFF Research Database (Denmark)

    Tenekecioglu, Erhan; Albuquerque, Felipe N; Sotomi, Yohei

    2017-01-01

    By providing valuable information about the coronary artery wall and lumen, intravascular imaging may aid in optimizing interventional procedure results and thereby could improve clinical outcomes following percutaneous coronary intervention (PCI). Intravascular optical coherence tomography (OCT...

  18. Computer tomography in otolaryngology

    International Nuclear Information System (INIS)

    Gradzki, J.

    1981-01-01

    The principles of design and the action of computer tomography which was applied also for the diagnosis of nose, ear and throat diseases are discussed. Computer tomography makes possible visualization of the structures of the nose, nasal sinuses and facial skeleton in transverse and eoronal planes. The method enables an accurate evaluation of the position and size of neoplasms in these regions and differentiation of inflammatory exudates against malignant masses. In otology computer tomography is used particularly in the diagnosis of pontocerebellar angle tumours and otogenic brain abscesses. Computer tomography of the larynx and pharynx provides new diagnostic data owing to the possibility of obtaining transverse sections and visualization of cartilage. Computer tomograms of some cases are presented. (author)

  19. Tomography in nuclear medicine

    International Nuclear Information System (INIS)

    Levi de Cabrejas, Mariana

    1999-01-01

    This book is a contribution to the training and diffusion of the tomography method image diagnosis in nuclear medicine, which principal purpose is the information to professionals and technical personnel, specially for the spanish speaking staff

  20. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info About Us News Physician Resources Professions Site Index A-Z Computed Tomography ( ...

  1. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info About Us News Physician Resources Professions Site Index A-Z Computed Tomography ( ...

  2. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities – hollow, air-filled spaces within the bones of the face surrounding the ...

  3. Introduction to Seismic Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Charlotte Anne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-21

    Tomography is a method of obtaining an image of a 3d object by observing the behavior of energy transmissions through the object. The image is obtained by Interrogating the object with Energy sources at a variety of Locations and observing the Object’s effects on the energy at a Variety of sensors. Tomography was first Used to build 3-dimensional Scans through Human bodies. These Are called computed Tomographic (ct) scans.

  4. Positron emission tomography

    International Nuclear Information System (INIS)

    Dvorak, O.

    1989-01-01

    The principle is briefly described of positron emission tomography, and its benefits and constraints are listed. It is emphasized that positron emission tomography (PET) provides valuable information on metabolic changes in the organism that are otherwise only very difficult to obtain, such as brain diagnosis including relationships between mental disorders and the physiology and pathophysiology of the brain. A PET machine is to be installed in Czechoslovakia in the near future. (L.O.)

  5. The new cold neutron tomography set-up at SINQ

    CERN Document Server

    Baechler, S; Cauwels, P; Dierick, M; Jolie, J; Materna, T; Mondelaers, W

    2002-01-01

    A new cold neutron tomography set-up is operational at the neutron spallation source SINQ of the Paul Scherrer Institute (PSI) in Villigen, Switzerland. The detection system is based on a sup 6 LiF/ZnS:Ag conversion screen and a CCD camera. Several tests have been carried out to characterize the quality of the tomography system, such as homogeneity, reproducibility, L/D-ratio and spatial resolution. The high flux and the good efficiency of the detector lead to very short exposure times. Thus, a typical set of tomography scans can be performed in only 20 min. Then, 3D computed tomography objects were calculated using the filtered back-projection reconstruction method. Initial results of various samples show that cold neutron tomography can be a useful tool for industry, geology and dentistry. Furthermore, suitable applications can be found in the field of archaeology.

  6. Fundamentals for routined utilization of tomography in beam diagnostic

    International Nuclear Information System (INIS)

    Reichau, Hermine

    2012-01-01

    A general and systematic approach to implement tomography for beam diagnostics has been invented and exemplarily shown for the invention of beam tomography for the Frankfurt Neutron Source. Following the diagnostic pipeline the first step was to prepare the data basis for the tomography reconstruction. For the monitoring, standard parameters have to be obtained with sufficient accuracy. In the context of this work, tomography has been kept as flexible as possible. Firstly, it will be used for the analysis of beam dynamics but also for the further development of beam tomography for routined utilization. Later on it will have to serve as a monitoring system at the end of the LEBT of FRANZ. The data preparation for tomography was demonstrated step by step. The iterated backprojection (FBP) algorithm was derived to show the basic idea of tomography which is contained in all forms of tomography algorithms. In connection with data exhibiting a high signal to noise ratio the FBP obtains the result with the highest accuracy, beyond that the accuracy can be controlled by the number of projections. The algebraic reconstruction and maximum entropy approach were outlined in a nutshell. By the introduction of the diagnostic pipeline in combination with the decision systematics the basis for a routined utilization of tomography in ion beam diagnostics have been established and exemplarily demonstrated on the introduction of beam tomography for FRANZ. A rotatable vacuum chamber has been developed to close a gap between the availability of projections to use the FBP and the small physical space on which they have to be determined. (orig.)

  7. Mathematics in computed tomography and related techniques

    International Nuclear Information System (INIS)

    Sawicka, B.

    1992-01-01

    The mathematical basis of computed tomography (CT) was formulated in 1917 by Radon. His theorem states that the 2-D function f(x,y) can be determined at all points from a complete set of its line integrals. Modern methods of image reconstruction include three approaches: algebraic reconstruction techniques with simultaneous iterative reconstruction or simultaneous algebraic reconstruction; convolution back projection; and the Fourier transform method. There is no one best approach. Because the experimental data do not strictly satisfy theoretical models, a number of effects have to be taken into account; in particular, the problems of beam geometry, finite beam dimensions and distribution, beam scattering, and the radiation source spectrum. Tomography with truncated data is of interest, employing mathematical approximations to compensate for the unmeasured projection data. Mathematical techniques in image processing and data analysis are also extensively used. 13 refs

  8. Principles of medical imaging with emphasis on tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kouris, K [Institute of Nuclear Medicine, University College, London Medical School, Mortimer Street, London W1N 8AA (United Kingdom)

    1994-12-31

    Medical imaging with ionizing and non-ionizing radiations belongs to the class of problems known as indirect sensing. This article is concerned with imaging methods known as image reconstruction from projections or computerized tomography. A brief comparative study of the theory is presented. Depending on the nature and modes of propagation of the employed radiation, methods are discussed either under transmission tomography (with gamma rays and X rays) or emission tomography (with gamma rays and positrons). Magnetic resonance Imaging (MRI) is described as resonant absorption and re-emission of radiofrequency energy. (author). 6 refs, 1 fig.

  9. Image processing tensor transform and discrete tomography with Matlab

    CERN Document Server

    Grigoryan, Artyom M

    2012-01-01

    Focusing on mathematical methods in computer tomography, Image Processing: Tensor Transform and Discrete Tomography with MATLAB(R) introduces novel approaches to help in solving the problem of image reconstruction on the Cartesian lattice. Specifically, it discusses methods of image processing along parallel rays to more quickly and accurately reconstruct images from a finite number of projections, thereby avoiding overradiation of the body during a computed tomography (CT) scan. The book presents several new ideas, concepts, and methods, many of which have not been published elsewhere. New co

  10. X-ray microtome by fluorescence tomography

    CERN Document Server

    Simionovici, A S; Guenzler, F; Schrör, C; Snigirev, A; Snigireva, I; Tümmler, J; Weitkamp, T

    2001-01-01

    The X-ray fluorescence microtomography method is presented, which is capable of virtually slicing samples to obtain cross-sections of their inner structure. High precision experimental results of fluo-tomography in 'pencil-beam' geometry with up to 1.2 mu m resolution are described. Image reconstructions are based on either a simplified algebraic reconstruction method (ART) or the filtered back-projection method (FBP). Phantoms of inhomogeneous test objects as well as biological samples are successfully analyzed.

  11. Development of electrical capacitance sensor for tomography

    International Nuclear Information System (INIS)

    Rasif Mohd Zain; Jaafar Abdullah; Ismail Mustapha; Sazrol Azizee Ariff; Susan Maria Sipaun; Lojius Lombigit

    2004-01-01

    Electrical capacitance tomography (ECT) is one of the successful methods for imaging 2-phase liquid/gas mixture in oil pipelines and solids/gas mixture in fluidized bed and pneumatic conveying system for improvement of process plants. This paper presents the design development of an electrical capacitance sensor for use with an ECT system. This project is aimed at developing a demonstration ECT unit to be used in the oil pipe line. (Author)

  12. Extraction of optical scattering parameters and attenuation compensation in optical coherence tomography images of multi-layered tissue structures

    DEFF Research Database (Denmark)

    Thrane, Lars; Frosz, Michael Henoch; Tycho, Andreas

    2004-01-01

    A recently developed analytical optical coherence tomography (OCT) model [Thrane et al., J. Opt. Soc. Am. A 17, 484 (2000)] allows the extraction of optical scattering parameters from OCT images, thereby permitting attenuation compensation in those images. By expanding this theoretical model, we...... have developed a new method for extracting optical scattering parameters from multilayered tissue structures in vivo. To verify this, we used a Monte Carlo (MC) OCT model as a numerical phantom to simulate the OCT signal for het-erogeneous multilayered tissue. Excellent agreement between the extracted......, and the results hold promise for expanding the functional imaging capabilities of OCT....

  13. Physics and instrumentation of emission computed tomography

    International Nuclear Information System (INIS)

    Links, J.M.

    1986-01-01

    Transverse emission computed tomography can be divided into two distinct classes: single photon emission computed tomography (SPECT) and positron emission tomography (PET). SPECT is usually accomplished with specially-adapted scintillation cameras, although dedicated SPECT scanners are available. The special SPECT cameras are standard cameras which are mounted on gantries that allow 360 degree rotation around the long axis of the head or body. The camera stops at a number of angles around the body (usually 64-128), acquiring a ''projection'' image at each stop. The data from these projections are used to reconstruct transverse images with a standard ''filtered back-projection'' algorithm, identical to that used in transmission CT. Because the scintillation camera acquires two-dimensional images, a simple 360 degree rotation around the patient results in the acquisition of data for a number of contiguous transverse slices. These slices, once reconstructed, can be ''stacked'' in computer memory, and orthogonal coronal and sagittal slices produced. Additionally, reorienting algorithms allow the generation of slices that are oblique to the long axis of the body

  14. Discrete tomography in neutron radiography

    International Nuclear Information System (INIS)

    Kuba, Attila; Rodek, Lajos; Kiss, Zoltan; Rusko, Laszlo; Nagy, Antal; Balasko, Marton

    2005-01-01

    Discrete tomography (DT) is an imaging technique for reconstructing discrete images from their projections using the knowledge that the object to be reconstructed contains only a few homogeneous materials characterized by known discrete absorption values. One of the main reasons for applying DT is that we will hopefully require relatively few projections. Using discreteness and some a priori information (such as an approximate shape of the object) we can apply two DT methods in neutron imaging by reducing the problem to an optimization task. The first method is a special one because it is only suitable if the object is composed of cylinders and sphere shapes. The second method is a general one in the sense that it can be used for reconstructing objects of any shape. Software was developed and physical experiments performed in order to investigate the effects of several reconstruction parameters: the number of projections, noise levels, and complexity of the object to be reconstructed. We give a summary of the experimental results and make a comparison of the results obtained using a classical reconstruction technique (FBP). The programs we developed are available in our DT reconstruction program package DIRECT

  15. Opt-Out Panel Testing for HIV, Hepatitis B and Hepatitis C in an Urban Emergency Department: A Pilot Study.

    Directory of Open Access Journals (Sweden)

    Sarah O'Connell

    Full Text Available Studies suggest 2 per 1000 people in Dublin are living with HIV, the level above which universal screening is advised. We aimed to assess the feasibility and acceptability of a universal opt-out HIV, Hepatitis B and Hepatitis C testing programme for Emergency Department patients and to describe the incidence and prevalence of blood-borne viruses in this population.An opt-out ED blood borne virus screening programme was piloted from March 2014 to January 2015. Patients undergoing blood sampling during routine clinical care were offered HIV 1&2 antibody/antigen assay, HBV surface antigen and HCV antibody tests. Linkage to care where necessary was co-ordinated by the study team. New diagnosis and prevalence rates were defined as the new cases per 1000 tested and number of positive tests per 1000 tested respectively.Over 45 weeks of testing, of 10,000 patient visits, 8,839 individual patient samples were available for analysis following removal of duplicates. A sustained target uptake of >50% was obtained after week 3. 97(1.09%, 44(0.49% and 447(5.05% HIV, Hepatitis B and Hepatitis C tests were positive respectively. Of these, 7(0.08%, 20(0.22% and 58(0.66% were new diagnoses of HIV, Hepatitis B and Hepatitis C respectively. The new diagnosis rate for HIV, Hepatitis B and Hepatitis C was 0.8, 2.26 and 6.5 per 1000 and study prevalence for HIV, Hepatitis B and Hepatitis C was 11.0, 5.0 and 50.5 per 1000 respectively.Opt-out blood borne viral screening was feasible and acceptable in an inner-city ED. Blood borne viral infections were prevalent in this population and newly diagnosed cases were diagnosed and linked to care. These results suggest widespread blood borne viral testing in differing clinical locations with differing population demographic risks may be warranted.

  16. Inverse scattering theory foundations of tomography with diffracting wavefields

    International Nuclear Information System (INIS)

    Devaney, A.J.

    1987-01-01

    The underlying mathematical models employed in reflection and transmission computed tomography using diffracting wavefields (called diffraction tomography) are reviewed and shown to have a rigorous basis in inverse scattering theory. In transmission diffraction tomography the underlying wave model is shown to be the Rytov approximation to the complex phase of the wavefield transmitted by the object being probed while in reflection diffraction tomography the underlying wave model is shown to be the Born approximation to the backscattered wavefield from the object. In both cases the goal of the reconstruction process is the determination of the objects's complex index of refraction as a function of position r/sup →/ and, possibly, the frequency ω of the probing wavefield. By use of these approximations the reconstruction problem for both transmission and reflection diffraction tomography can be cast into the simple and elegant form of linearized inverse scattering theory. Linearized inverse scattering theory is shown to lead directly to generalized projection-slice theorems for both reflection and transmission diffraction tomography that provide a simple mathematical relationship between the object's complex index of refraction (the unknown) and the data (the complex phase of the transmitted wave or the complex amplitude of the reflected wave). The conventional projection-slice theorem of X-ray CT is shown to result from the generalized projection-slice theorem for transmission diffraction tomography in the limit of vanishing wavelength (in the absence of wave effects). Fourier based and back-projection type reconstruction algorithms are shown to be directly derivable from the generalized projection-slice theorems

  17. Inter laboratory comparison on Industrial Computed Tomography

    DEFF Research Database (Denmark)

    Angel, Jais Andreas Breusch; De Chiffre, Leonardo; Larsen, Erik

    The ‘CIA-CT comparison - Inter laboratory comparison on industrial Computed Tomography” is organized by DTU Department of Mechanical Engineering within the Danish project “Centre for Industrial Application of CT scanning - CIA-CT”. The project is co-financed by the Danish Ministry of Science......, Technology and Innovation. The comparison aims to collect information about measurement performance in state-of the-art industrial CT (Computed Tomography) scanning. Since CT scanning has entered the field of manufacturing and coordinate metrology, evaluation of uncertainty of measurement with assessment...

  18. Quantitative cardiac computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Thelen, M.; Dueber, C.; Wolff, P.; Erbel, R.; Hoffmann, T.

    1985-06-01

    The scope and limitations of quantitative cardiac CT have been evaluated in a series of experimental and clinical studies. The left ventricular muscle mass was estimated by computed tomography in 19 dogs (using volumetric methods, measurements in two axes and planes and reference volume). There was good correlation with anatomical findings. The enddiastolic volume of the left ventricle was estimated in 22 patients with cardiomyopathies; using angiography as a reference, CT led to systematic under-estimation. It is also shown that ECG-triggered magnetic resonance tomography results in improved visualisation and may be expected to improve measurements of cardiac morphology.

  19. Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Mogensen, Mette; Themstrup, Lotte; Banzhaf, Christina

    2014-01-01

    Optical coherence tomography (OCT) has developed rapidly since its first realisation in medicine and is currently an emerging technology in the diagnosis of skin disease. OCT is an interferometric technique that detects reflected and backscattered light from tissue and is often described as the o......Optical coherence tomography (OCT) has developed rapidly since its first realisation in medicine and is currently an emerging technology in the diagnosis of skin disease. OCT is an interferometric technique that detects reflected and backscattered light from tissue and is often described...

  20. Client’s flexibility in renovation projects with long-term DBFMO contracts

    NARCIS (Netherlands)

    Kuhlmann, M.; Blokhuis, E.G.J.; Han, Q.; Schaefer, W.F.; Yildiz, H.T.

    2009-01-01

    Construction project clients are faced with long-term commitments when opting for a DBFMO contract, the Dutch version of PFI. This way of contracting is characterized by the delivery of a full housing service to the client over a period of decades, offered by a construction consortium including

  1. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is ... a CT scan. View full size with caption Pediatric Content Some imaging tests and treatments have special ...

  2. Children's (Pediatric) CT (Computed Tomography)

    Medline Plus

    Full Text Available ... Site Index A-Z Children's (Pediatric) CT (Computed Tomography) Pediatric computed tomography (CT) is a fast, painless exam that uses ... of Children's CT? What is Children's CT? Computed tomography, more commonly known as a CT or CAT ...

  3. Computed tomography in facial trauma

    International Nuclear Information System (INIS)

    Zilkha, A.

    1982-01-01

    Computed tomography (CT), plain radiography, and conventional tomography were performed on 30 patients with facial trauma. CT demonstrated bone and soft-tissue involvement. In all cases, CT was superior to tomography in the assessment of facial injury. It is suggested that CT follow plain radiography in the evaluation of facial trauma

  4. Multislice computed tomography coronary angiography

    NARCIS (Netherlands)

    F. Cademartiri (Filippo)

    2005-01-01

    markdownabstract__Abstract__ Computed Tomography (CT) imaging is also known as "CAT scanning" (Computed Axial Tomography). Tomography is from the Greek word "tomos" meaning "slice" or "section" and "graphia" meaning "describing". CT was invented in 1972 by British engineer Godfrey Hounsfield

  5. Qualitative and quantitative assessment of the short- and long-term consequences of opting out of nuclear energy

    International Nuclear Information System (INIS)

    Briem, G.; Halstrick, M.; Heilemann, U.; Hillebrand, B.; Kiy, M.; Neuhaus, R.; Knieper, O.; Schmidt, H.W.; Weiss, T.

    1986-08-01

    A reference scenario establishes the prospective development of the energy and overall economy under status-quo conditions, i.e. assuming especially the continued use of nuclear energy, while two scenarios (alternative I: 'immediate opting out' and alternative II: 'opting out in the long term') try to assess the consequences of a shutdown of nuclear energy for the economic development of the Federal Republic of Germany. Especially, the study deals with the effects on the power industry, the ecological consequences, and the overall economic effects both in the short and long run. In all three scenarios, the development of the home consumption of electric power is first of all determined by a structure model of the entire economy. The capacity required to meet that demand and its use are calculated with the aid of a power plant model; short- and long-term cost-minimization programmes making allowance especially for fuel and capital costs from the elements from which these quantities are derived. Fuel and capital costs operate as variables in the structure model to determine the sectoral and overall economic development. The report in addition investigates separately, in partial models, the effects on the chemical industry and the branches of industry processing iron, steel, and non-ferrous metals, all of which are greatly in demand of electric power. (orig./UA) [de

  6. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Head ...

  7. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Sinuses ...

  8. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Share your patient story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related ...

  9. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Share your patient story here Images × Image Gallery Patient undergoing computed tomography (CT) scan. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related ...

  10. Computed tomography in traumatology

    International Nuclear Information System (INIS)

    Heller, M.; Jend, H.H.

    1986-01-01

    This volume offers a critical review and assessment of new avenues opened up by computed tomography in traumatology. Over 200 illustrations, including numerous CT scans, aid the physician engaged emergency care and postoperative treatment of accident victims. Technical prerequisites, special techniques of investigation, pathomorphology of organ changes conditioned by trauma, diagnostic leading symptoms and signs, and diagnostics of iatrogenic injuries and lesions are presented

  11. Computed tomography system

    International Nuclear Information System (INIS)

    Lambert, T.W.; Blake, J.E.

    1981-01-01

    This invention relates to computed tomography and is particularly concerned with determining the CT numbers of zones of interest in an image displayed on a cathode ray tube which zones lie in the so-called level or center of the gray scale window. (author)

  12. Holography and tomography

    Energy Technology Data Exchange (ETDEWEB)

    Howells, M. [Lawrence Berkeley National Lab., CA (United States)

    1997-02-01

    This session includes a collection of outlines of pertinent information, diagrams, graphs, electron micrographs, and color photographs pertaining to historical aspects and recent advances in the development of X-ray Gabor Holography. Many of the photographs feature or pertain to instrumentation used in holography, tomography, and cryo-holography.

  13. Celebral computerized tomography

    International Nuclear Information System (INIS)

    Lofteroed, B.; Sortland, O.

    1985-01-01

    Indications for cerebral computerized tomography (CT) and the diagnostic results from this examination are evaluated in 127 children. Pathological changes were found in 31 children, mostly based on such indications as increasing head size, suspicion of brain tumor, cerebral paresis, delayed psychomotor development and epileptic seizures. A list of indications for CT in children is given

  14. Chest computed tomography

    DEFF Research Database (Denmark)

    Loeve, Martine; Krestin, Gabriel P.; Rosenfeld, Margaret

    2013-01-01

    are not suitable to study CF lung disease in young children. Chest computed tomography (CT) holds great promise for use as a sensitive surrogate endpoint in CF. A large body of evidence has been produced to validate the use of chest CT as primary endpoint to study CF lung disease. However, before chest CT can...

  15. Positron emission tomography

    NARCIS (Netherlands)

    Paans, AMJ

    Positron Emission Tomography (PET) is a method for determining biochemical and physiological processes in vivo in a quantitative way by using radiopharmaceuticals labelled with positron emitting radionuclides as C-11, N-13, O-15 and F-18 and by measuring the annihilation radiation using a

  16. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Computed tomography (CT) of the head uses special x-ray equipment to help assess head injuries, severe headaches, ... is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside ...

  17. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... Computed tomography (CT) of the sinuses uses special x-ray equipment to evaluate the paranasal sinus cavities – hollow, ... is a diagnostic medical test that, like traditional x-rays, produces multiple images or pictures of the inside ...

  18. Computed tomography for radiographers

    International Nuclear Information System (INIS)

    Brooker, M.J.

    1986-01-01

    This book is directed towards giving radiographers an introduction to and basic knowledge of computerized tomography. The technical section discusses gantries and x-ray production, computer and disc drive image display, storage, artefacts quality assurance and design of departments. The clinical section includes patient preparation, radiotherapy planning, and interpretation of images from various areas of the anatomy. (U.K.)

  19. Holography and tomography

    International Nuclear Information System (INIS)

    Howells, M.

    1997-01-01

    This session includes a collection of outlines of pertinent information, diagrams, graphs, electron micrographs, and color photographs pertaining to historical aspects and recent advances in the development of X-ray Gabor Holography. Many of the photographs feature or pertain to instrumentation used in holography, tomography, and cryo-holography

  20. Geometric reconstruction methods for electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Alpers, Andreas, E-mail: alpers@ma.tum.de [Zentrum Mathematik, Technische Universität München, D-85747 Garching bei München (Germany); Gardner, Richard J., E-mail: Richard.Gardner@wwu.edu [Department of Mathematics, Western Washington University, Bellingham, WA 98225-9063 (United States); König, Stefan, E-mail: koenig@ma.tum.de [Zentrum Mathematik, Technische Universität München, D-85747 Garching bei München (Germany); Pennington, Robert S., E-mail: robert.pennington@uni-ulm.de [Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark); Boothroyd, Chris B., E-mail: ChrisBoothroyd@cantab.net [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Houben, Lothar, E-mail: l.houben@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Dunin-Borkowski, Rafal E., E-mail: rdb@fz-juelich.de [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich (Germany); Joost Batenburg, Kees, E-mail: Joost.Batenburg@cwi.nl [Centrum Wiskunde and Informatica, NL-1098XG, Amsterdam, The Netherlands and Vision Lab, Department of Physics, University of Antwerp, B-2610 Wilrijk (Belgium)

    2013-05-15

    Electron tomography is becoming an increasingly important tool in materials science for studying the three-dimensional morphologies and chemical compositions of nanostructures. The image quality obtained by many current algorithms is seriously affected by the problems of missing wedge artefacts and non-linear projection intensities due to diffraction effects. The former refers to the fact that data cannot be acquired over the full 180° tilt range; the latter implies that for some orientations, crystalline structures can show strong contrast changes. To overcome these problems we introduce and discuss several algorithms from the mathematical fields of geometric and discrete tomography. The algorithms incorporate geometric prior knowledge (mainly convexity and homogeneity), which also in principle considerably reduces the number of tilt angles required. Results are discussed for the reconstruction of an InAs nanowire. - Highlights: ► Four algorithms for electron tomography are introduced that utilize prior knowledge. ► Objects are assumed to be homogeneous; convexity and regularity is also discussed. ► We are able to reconstruct slices of a nanowire from as few as four projections. ► Algorithms should be selected based on the specific reconstruction task at hand.

  1. Geometric reconstruction methods for electron tomography

    International Nuclear Information System (INIS)

    Alpers, Andreas; Gardner, Richard J.; König, Stefan; Pennington, Robert S.; Boothroyd, Chris B.; Houben, Lothar; Dunin-Borkowski, Rafal E.; Joost Batenburg, Kees

    2013-01-01

    Electron tomography is becoming an increasingly important tool in materials science for studying the three-dimensional morphologies and chemical compositions of nanostructures. The image quality obtained by many current algorithms is seriously affected by the problems of missing wedge artefacts and non-linear projection intensities due to diffraction effects. The former refers to the fact that data cannot be acquired over the full 180° tilt range; the latter implies that for some orientations, crystalline structures can show strong contrast changes. To overcome these problems we introduce and discuss several algorithms from the mathematical fields of geometric and discrete tomography. The algorithms incorporate geometric prior knowledge (mainly convexity and homogeneity), which also in principle considerably reduces the number of tilt angles required. Results are discussed for the reconstruction of an InAs nanowire. - Highlights: ► Four algorithms for electron tomography are introduced that utilize prior knowledge. ► Objects are assumed to be homogeneous; convexity and regularity is also discussed. ► We are able to reconstruct slices of a nanowire from as few as four projections. ► Algorithms should be selected based on the specific reconstruction task at hand

  2. Computed tomography of cryogenic cells

    International Nuclear Information System (INIS)

    Schneider, Gerd; Anderson, E.; Vogt, S.; Knochel, C.; Weiss, D.; LeGros, M.; Larabell, C.

    2001-01-01

    Due to the short wavelengths of X-rays and low numerical aperture of the Fresnel zone plates used as X-ray objectives, the depth of field is several microns. Within the focal depth, imaging a thick specimen is to a good approximation equivalent to projecting the specimen absorption. Therefore, computed tomography based on a tilt series of X-ray microscopic images can be used to reconstruct the local linear absorption coefficient and image the three-dimensional specimen structure. To preserve the structural integrity of biological objects during image acquisition, microscopy is performed at cryogenic temperatures. Tomography based on X-ray microscopic images was applied to study the distribution of male specific lethal 1 (MSL-1), a nuclear protein involved in dosage compensation in Drosophila melanogaster, which ensures that males with single X chromosome have the same amount of most X-linked gene products as females with two X chromosomes. Tomographic reconstructions of X-ray microscopic images were used to compute the local three-dimensional linear absorption coefficient revealing the arrangement of internal structures of Drosophila melanogaster cells. Combined with labelling techniques, nanotomography is a new technique to study the 3D distribution of selected proteins inside whole cells. We want to improve this technique with respect to resolution and specimen preparation. The resolution in the reconstruction can be significantly improved by reducing the angular step size to collect more viewing angles, which requires an automated data acquisition. In addition, fast-freezing with liquid ethane instead of cryogenic He gas will be applied to improve the vitrification of the hydrated samples. We also plan to apply cryo X-ray nanotomography in order to study different types of cells and their nuclear protein distributions

  3. Ethical issues surrounding the provider initiated opt--Out prenatal HIV screening practice in Sub-Saharan Africa: a literature review.

    Science.gov (United States)

    Bain, Luchuo Engelbert; Dierickx, Kris; Hens, Kristien

    2015-10-24

    Prevention of mother to child transmission of HIV remains a key public health priority in most developing countries. The provider Initiated Opt - Out Prenatal HIV Screening Approach, recommended by the World Health Organization (WHO) lately has been adopted and translated into policy in most Sub - Saharan African countries. To better ascertain the ethical reasons for or against the use of this approach, we carried out a literature review of the ethics literature. Papers published in English and French Languages between 1990 and 2015 from the following data bases were searched: Pubmed, Cochrane literature, Embase, Cinhal, Web of Science and Google Scholar. After screening from 302 identified relevant articles, 21 articles were retained for the critical review. Most authors considered this approach ethically justifiable due to its potential benefits to the mother, foetus and society (Beneficence). The breaching of respect for autonomy was considered acceptable on the grounds of libertarian paternalism. Most authors considered the Opt - Out approach to be less stigmatizing than the Opt - In. The main arguments against the Opt - Out approach were: non respect of patient autonomy, informed consent becoming a meaningless concept and the HIV test becoming compulsory, risk of losing trust in health care providers, neglect of social and psychological implications of doing an HIV test, risk of aggravation of stigma if all tested patients are not properly cared for and neglect of sociocultural peculiarities. The Opt - Out approach could be counterproductive in case gender sensitive issues within the various sociocultural representations are neglected, and actions to offer holistic care to all women who shall potentially test positive for HIV were not effectively ascertained. The Provider Initiated Opt - Out Prenatal HIV Screening option remains ethically acceptable, but deserves caution, active monitoring and evaluation within the translation of this approach into to practice.

  4. Is 'Opt-Out HIV Testing' a real option among pregnant women in rural districts in Kenya?

    Directory of Open Access Journals (Sweden)

    Wamalwa David

    2011-03-01

    Full Text Available Abstract Background An 'opt-out' policy of routine HIV counseling and testing (HCT is being implemented across sub-Saharan Africa to expand prevention of mother-to-child transmission (PMTCT. Although the underlying assumption is that pregnant women in rural Africa are able to voluntarily consent to HIV testing, little is known about the reality and whether 'opt-out' HCT leads to higher completion rates of PMTCT. Factors associated with consent to HIV testing under the 'opt-out' approach were investigated through a large cross-sectional study in Kenya. Methods Observations during HIV pre-test information sessions were followed by a cross-sectional survey of 900 pregnant women in three public district hospitals carrying out PMTCT in the Busia district. Women on their first antenatal care (ANC visit during the current pregnancy were interviewed after giving blood for HIV testing but before learning their test results. Descriptive statistics and multivariate regression analysis were performed. Results Of the 900 women participating, 97% tested for HIV. Lack of testing kits was the only reason for women not being tested, i.e. nobody declined HIV testing. Despite the fact that 96% had more than four earlier pregnancies and 37% had been tested for HIV at ANC previously, only 17% of the women surveyed knew that testing was optional. Only 20% of those surveyed felt they could make an informed decision to decline HIV testing. Making an informed decision to decline HIV testing was associated with knowing that testing was optional (OR = 5.44, 95%CI 3.44-8.59, not having a stable relationship with the child's father (OR = 1.76, 95%CI 1.02-3.03, and not having discussed HIV testing with a partner before the ANC visit (OR = 2.64 95%CI 1.79-3.86. Conclusion High coverage of HIV testing appears to be achieved at the cost of pregnant women not understanding that testing is optional. Good quality HIV pre-test information is central to ensure that pregnant women

  5. Wave Power Demonstration Project at Reedsport, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Mekhiche, Mike [Principal Investigator; Downie, Bruce [Project Manager

    2013-10-21

    Ocean wave power can be a significant source of large‐scale, renewable energy for the US electrical grid. The Electrical Power Research Institute (EPRI) conservatively estimated that 20% of all US electricity could be generated by wave energy. Ocean Power Technologies, Inc. (OPT), with funding from private sources and the US Navy, developed the PowerBuoy to generate renewable energy from the readily available power in ocean waves. OPT's PowerBuoy converts the energy in ocean waves to electricity using the rise and fall of waves to move the buoy up and down (mechanical stroking) which drives an electric generator. This electricity is then conditioned and transmitted ashore as high‐voltage power via underwater cable. OPT's wave power generation system includes sophisticated techniques to automatically tune the system for efficient conversion of random wave energy into low cost green electricity, for disconnecting the system in large waves for hardware safety and protection, and for automatically restoring operation when wave conditions normalize. As the first utility scale wave power project in the US, the Wave Power Demonstration Project at Reedsport, OR, will consist of 10 PowerBuoys located 2.5 miles off the coast. This U.S. Department of Energy Grant funding along with funding from PNGC Power, an Oregon‐based electric power cooperative, was utilized for the design completion, fabrication, assembly and factory testing of the first PowerBuoy for the Reedsport project. At this time, the design and fabrication of this first PowerBuoy and factory testing of the power take‐off subsystem are complete; additionally the power take‐off subsystem has been successfully integrated into the spar.

  6. Highly resolving computerized tomography

    International Nuclear Information System (INIS)

    Kurtz, B.; Petersen, D.; Walter, E.

    1984-01-01

    With the development of highly-resolving devices for computerized tomography, CT diagnosis of the lumbar vertebral column has gained increasing importance. As an ambulatory, non-invasive method it has proved in comparative studies to be at least equivalent to myelography in the detection of dislocations of inter-vertebral disks (4,6,7,15). Because with modern devices not alone the bones, but especially the spinal soft part structures are clearly and precisely presented with a resolution of distinctly below 1 mm, a further improvement of the results is expected as experience will increase. The authors report on the diagnosis of the lumbar vertebral column with the aid of a modern device for computerized tomography and wish to draw particular attention to the possibility of doing this investigation as a routine, and to the diagnostic value of secondary reconstructions. (BWU) [de

  7. Highly resolving computerized tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, B.; Petersen, D.; Walter, E.

    1984-01-01

    With the development of highly-resolving devices for computerized tomography, CT diagnosis of the lumbar vertebral column has gained increasing importance. As an ambulatory, non-invasive method it has proved in comparative studies to be at least equivalent to myelography in the detection of dislocations of inter-vertebral disks (4,6,7,15). Because with modern devices not alone the bones, but especially the spinal soft part structures are clearly and precisely presented with a resolution of distinctly below 1 mm, a further improvement of the results is expected as experience will increase. The authors report on the diagnosis of the lumbar vertebral column with the aid of a modern device for computerized tomography and wish to draw particular attention to the possibility of doing this investigation as a routine, and to the diagnostic value of secondary reconstructions.

  8. Mathematical Methods in Tomography

    CERN Document Server

    Louis, Alfred; Natterer, Frank

    1991-01-01

    The conference was devoted to the discussion of present and future techniques in medical imaging, including 3D x-ray CT, ultrasound and diffraction tomography, and biomagnetic ima- ging. The mathematical models, their theoretical aspects and the development of algorithms were treated. The proceedings contains surveys on reconstruction in inverse obstacle scat- tering, inversion in 3D, and constrained least squares pro- blems.Research papers include besides the mentioned imaging techniques presentations on image reconstruction in Hilbert spaces, singular value decompositions, 3D cone beam recon- struction, diffuse tomography, regularization of ill-posed problems, evaluation reconstruction algorithms and applica- tions in non-medical fields. Contents: Theoretical Aspects: J.Boman: Helgason' s support theorem for Radon transforms-a newproof and a generalization -P.Maass: Singular value de- compositions for Radon transforms- W.R.Madych: Image recon- struction in Hilbert space -R.G.Mukhometov: A problem of in- teg...

  9. Neutron beam tomography software

    International Nuclear Information System (INIS)

    Newbery, A.C.R.

    1988-05-01

    When a sample is traversed by a neutron beam, inhomogeneities in the sample will cause deflections, and the deflections will permit conclusions to be drawn concerning the location and size of the inhomogeneities. The associated computation is similar to problems in tomography, analogous to X-ray tomography though significantly different in detail. We do not have any point-sample information, but only mean values over short line segments. Since each mean value is derived from a separate neutron counter, the quantity of available data has to be modest; also, since each datum is an integral, its geometric precision is inferior to that of X-ray data. Our software is designed to cope with these difficulties. (orig.) [de

  10. Positron emission tomography

    International Nuclear Information System (INIS)

    Yamamoto, Y.L.; Thompson, C.J.; Diksic, M.; Meyer, E.; Feindel, W.H.

    1984-01-01

    One of the most exciting new technologies introduced in the last 10 yr is positron emission tomography (PET). PET provides quantitative, three-dimensional images for the study of specific biochemical and physiological processes in the human body. This approach is analogous to quantitative in-vivo autoradiography but has the added advantage of permitting non-invasive in vivo studies. PET scanning requires a small cyclotron to produce short-lived positron emitting isotopes such as oxygen-15, carbon-11, nitrogen-13 and fluorine-18. Proper radiochemical facilities and advanced computer equipment are also needed. Most important, PET requires a multidisciplinary scientific team of physicists, radiochemists, mathematicians, biochemists and physicians. The most recent trends are reviewed in the imaging technology, radiochemistry, methodology and clinical applications of positron emission tomography. (author)

  11. Reinforced concrete tomography

    International Nuclear Information System (INIS)

    Mariscotti, M.A.J.; Morixe, M.; Tarela, P.A.; Thieberger, P.

    1997-01-01

    In this paper we describe the technique of reinforced concrete tomography, its historical background, recent technological developments and main applications. Gamma radiation sensitive plates are imprinted with radiation going through the concrete sample under study, and then processed to reveal the presence of reinforcement and defects in the material density. The three dimensional reconstruction, or tomography, of the reinforcement out of a single gammagraphy is an original development alternative to conventional methods. Re-bar diameters and positions may be determined with an accuracy of ± 1 mm 0.5-1 cm, respectively. The non-destructive character of this technique makes it particularly attractive in cases of inhabited buildings and diagnoses of balconies. (author) [es

  12. Computed Tomography. Chapter 11

    Energy Technology Data Exchange (ETDEWEB)

    Geleijns, J. [Leiden University Medical Centre, Leiden (Netherlands)

    2014-09-15

    After its clinical introduction in 1971, computed tomography (CT) developed from an X ray modality that was limited to axial imaging of the brain in neuroradiology into a versatile 3-D whole body imaging modality for a wide range of applications, including oncology, vascular radiology, cardiology, traumatology and interventional radiology. CT is applied for diagnosis and follow-up studies of patients, for planning of radiotherapy, and even for screening of healthy subpopulations with specific risk factors.

  13. Positron emission tomography

    International Nuclear Information System (INIS)

    Chandrasekhar, Preethi; Himabindu, Pucha

    2000-01-01

    Positron Emission Tomography (PET) is a non-invasive nuclear imaging technique used to study different molecular pathways and anatomical structures. PET has found extensive applications in various fields of medicine viz. cardiology, oncology, psychiatry/psychology, neuro science and pulmonology. This study paper basically deals with the physics, chemistry and biology behind the PET technique. It discusses the methodology for generation of the radiotracers responsible for emission of positrons and the annihilation and detection techniques. (author)

  14. Compton tomography system

    Science.gov (United States)

    Grubsky, Victor; Romanoov, Volodymyr; Shoemaker, Keith; Patton, Edward Matthew; Jannson, Tomasz

    2016-02-02

    A Compton tomography system comprises an x-ray source configured to produce a planar x-ray beam. The beam irradiates a slice of an object to be imaged, producing Compton-scattered x-rays. The Compton-scattered x-rays are imaged by an x-ray camera. Translation of the object with respect to the source and camera or vice versa allows three-dimensional object imaging.

  15. High resolution positron tomography

    International Nuclear Information System (INIS)

    Brownell, G.L.; Burnham, C.A.

    1982-01-01

    The limits of spatial resolution in practical positron tomography are examined. The four factors that limit spatial resolution are: positron range; small angle deviation; detector dimensions and properties; statistics. Of these factors, positron range may be considered the fundamental physical limitation since it is independent of instrument properties. The other factors are to a greater or lesser extent dependent on the design of the tomograph

  16. Positron emission tomography

    International Nuclear Information System (INIS)

    Marchenkov, N.S.

    2000-01-01

    The foundations of the positron emission tomography (PET), widely used for the medical diagnostics, are considered. The brief description of the cyclotron for production of radionuclides, applied in the PET, the target devices for manufacturing the position emitters, the moduli for the radiopharmaceuticals synthesis (RPS) for the PET is presented. The necessity and concept of complete automation of the RPS for the PET are discussed [ru

  17. Computed Tomography Status

    Science.gov (United States)

    Hansche, B. D.

    1983-01-01

    Computed tomography (CT) is a relatively new radiographic technique which has become widely used in the medical field, where it is better known as computerized axial tomographic (CAT) scanning. This technique is also being adopted by the industrial radiographic community, although the greater range of densities, variation in samples sizes, plus possible requirement for finer resolution make it difficult to duplicate the excellent results that the medical scanners have achieved.

  18. EDITORIAL: Optical tomography and digital holography

    Science.gov (United States)

    Coupland, Jeremy; Lobera, Julia

    2008-07-01

    this for the case of mono-disperse particles in air. Here the number density of the particles is such that multiple scattering is prevalent; however, a priori knowledge of particle size and refractive index allows individual particles to be located accurately. In general, reconstruction can be thought of as a nonlinear optimization process that is used to discover the object which best explains the measured field and is consistent with a priori information. As Gire et al point out in their article, a priori knowledge can also be used to overcome the Nyquist sampling criteria. Although some caution should be exercised (for example, it is not usually possible to decide whether a given solution is unique), it is interesting to note that despite the disparity in resolution, digital holography and computer technology might yet create 3D images of greater clarity than the best optical holograms. References [1] Schnars U and Jueptner W 2005 Digital Holography (Berlin: Springer) ISBN: 978 3 540 21934 7 [2] Gabor D 1948 A new microscopic principle Nature 161 777-8 [3] Bjelkhagen H I 1993 Silver-Halide Recording Materials (Berlin: Springer) ISBN 3 540 58619 9 [4] Leendertz J A 1970 Interferometric displacement measurement on scattering surfaces utilizing speckle effect J. Phys. E: Sci. Instrum. 3 214-8 [5] Marquet P, Rappaz B, Magistretti P J, Cuche E, Emery Y, Colomb T and Depeursinge C 2005 Digital holographic microscopy: a noninvasive contrast imaging technique allowing quantitative visualization of living cells with subwavelength axial accuracy Opt. Lett. 30 468-70 [6] Wolf E 1969 Three-dimensional structure determination of semi-transparent objects from holographic data Opt. Commun. 1 153-6 [7] Dandliker R and Weiss K 1970 Reconstruction of the three-dimensional refractive index from scattered waves Opt. Commun. 1 323-8 [8] Coupland J and Lobera J 2007 International Workshop on Digital Holographic Reconstruction and Optical Tomography for Engineering Applications ISBN 978 0

  19. Coded aperture tomography revisited

    International Nuclear Information System (INIS)

    Bizais, Y.; Rowe, R.W.; Zubal, I.G.; Bennett, G.W.; Brill, A.B.

    1983-01-01

    Coded aperture (CA) Tomography never achieved wide spread use in Nuclear Medicine, except for the degenerate case of Seven Pinhole tomagraphy (7PHT). However it enjoys several attractive features (high sensitivity and tomographic ability with a statis detector). On the other hand, resolution is usually poor especially along the depth axis and the reconstructed volume is rather limited. Arguments are presented justifying the position that CA tomography can be useful for imaging time-varying 3D structures, if its major drawbacks (poor longitudinal resolution and difficulty in quantification) are overcome. Poor results obtained with 7PHT can be explained by both a very limited angular range sampled and a crude modelling of the image formation process. Therefore improvements can be expected by the use of a dual-detector system, along with a better understanding of its sampling properties and the use of more powerful reconstruction algorithms. Non overlapping multipinhole plates, because they do not involve a decoding procedure, should be considered first for practical applications. Use of real CA should be considered for cases in which non overlapping multipinhole plates do not lead to satisfactory solutions. We have been and currently are carrying out theoretical and experimental works, in order to define the factors which limit CA imaging and to propose satisfactory solutions for Dynamic Emission Tomography

  20. Cardiac positron tomography

    International Nuclear Information System (INIS)

    Geltmann, E.M.; Roberts, R.; Sobel, B.E.

    1980-01-01

    Positron emission tomography (PET) performed after the administration of the positron-emitting radionuclides carbon-11 ( 11 C), nitrogen-13 ( 13 N), oxygen-15 ( 15 O) and fluorine-18 ( 18 F) has permitted the improved noninvasive assessment of the regional myocardial metabolism of normal physiologic substrates and intermediates and their cogeners. In experimental animals, the rate of oxidation of 11 C-palmitate correlates closely with other indexes of oxygen consumption, and the extraction of 11 C-palmitate (like that of 18 F-fatty acids and 18 F-fluoredoxyglucose) ist markedly diminished in regions of myocardial ischemia. In both experimental animals and in patients, myocardial infarct site and size, determined by positron emission tomography after the intravenous injection of 11 C-palmitate, correlate closely with the electrocardiographic infarct locus and enzymatically estimated infarct size as well as with the location and extent of regional left ventricular wall motion abnormalities. PET offers promise for assessment of flow as well despite the complexities involved. PET with 13 NH 3 appears to provide one useful qualitative index, although this tracer ist actively metabolized. Because of the quantitative capabilities of positron emission tomography and the rapid progress which is being made in the development of fast scan, multi-slice, and gated instrumentation, this technique is likely to facilitate improved understanding and characterization of regional myocardial metabolism and blood flow in man under physiological and pathophysiological conditions. (orig.) [de

  1. Neutron stimulated emission computed tomography: Background corrections

    International Nuclear Information System (INIS)

    Floyd, Carey E.; Sharma, Amy C.; Bender, Janelle E.; Kapadia, Anuj J.; Xia, Jessie Q.; Harrawood, Brian P.; Tourassi, Georgia D.; Lo, Joseph Y.; Kiser, Matthew R.; Crowell, Alexander S.; Pedroni, Ronald S.; Macri, Robert A.; Tajima, Shigeyuki; Howell, Calvin R.

    2007-01-01

    Neutron stimulated emission computed tomography (NSECT) is an imaging technique that provides an in-vivo tomographic spectroscopic image of the distribution of elements in a body. To achieve this, a neutron beam illuminates the body. Nuclei in the body along the path of the beam are stimulated by inelastic scattering of the neutrons in the beam and emit characteristic gamma photons whose unique energy identifies the element. The emitted gammas are collected in a spectrometer and form a projection intensity for each spectral line at the projection orientation of the neutron beam. Rotating and translating either the body or the beam will allow a tomographic projection set to be acquired. Images are reconstructed to represent the spatial distribution of elements in the body. Critical to this process is the appropriate removal of background gamma events from the spectrum. Here we demonstrate the equivalence of two background correction techniques and discuss the appropriate application of each

  2. System Matrix Analysis for Computed Tomography Imaging

    Science.gov (United States)

    Flores, Liubov; Vidal, Vicent; Verdú, Gumersindo

    2015-01-01

    In practical applications of computed tomography imaging (CT), it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data. PMID:26575482

  3. Do PhDs Voluntarily Opt for Private Sector Employment? Evidence of Push and Pull Effects on Mobility Choices

    DEFF Research Database (Denmark)

    Pedersen, Heidi Skovgaard

    2014-01-01

    In Denmark, policy makers have increased admissions to PhD programs to ensure the flow of researchers into the private sector, thereby increasing knowledge transfer. However, we know little about the factors influencing the sector mobility of PhD graduates. While opting for employment...... in the private sector might be driven by personal preferences, there might also be external factors pushing PhDs to choose the private sector. This article examines the push and pull effects on mobility choices using duration models to estimate the transition rates to private sector employment. The analyses show...... that the preference for and ability to do academic science reduces transition rates to the private sector, whereas being in a research position and earnings potential are attractors to the private sector. Hence, both push and pull effects determine sector mobility. Once the initial sector choice has been made...

  4. Perineal injuries and birth positions among 2992 women with a low risk pregnancy who opted for a homebirth

    DEFF Research Database (Denmark)

    Edqvist, Malin; Blix, Ellen; Hegaard, Hanne K

    2016-01-01

    at home and to compare the prevalence of perineal injuries, SPT and episiotomy in different birth positions in four Nordic countries. METHODS: A population-based prospective cohort study of planned home births in four Nordic countries. To assess medical outcomes a questionnaire completed after birth...... by the attending midwife was used. Descriptive statistics, bivariate analysis and logistic regression were used to analyze the data. RESULTS: Two thousand nine hundred ninety-two women with planned home births, who birthed spontaneously at home or after transfer to hospital, between 2008 and 2013 were included.......26-1.79). Flexible sacrum positions were associated with fewer episiotomies (OR 0.20; CI 95 % 0.10-0.54). CONCLUSION: A low prevalence of SPT and episiotomy was found among women opting for a home birth in four Nordic countries. Women used a variety of birth positions and a majority gave birth in flexible sacrum...

  5. Nuclear power and the opting-out policy of the German Government. A matter of responsibility and controversy

    International Nuclear Information System (INIS)

    Grawe, J.; Voss, A.

    2000-01-01

    The article critically reviews the energy policy of the German Government and the plans for winding down nuclear power generation and instead pursue a policy for a ''green reshufflement'' of generation technologies, providing for incentives to switch to options for decentralized power generation with enhanced use of renewable energy sources. The article explains arguments against the Government's opting-out policy which were laid down in a memorandum presented to the Government by a group of five university professors, among them the authors of this article who, as experts in this domain, are aware of their responsibility as scientists and members of society and therefore explain their view of the policy issues, also referring to a recent expert opinion of the German Wissenschaftsrat (science council), which recommended to continue nuclear energy research programmes and nuclear power generation. (orig./CB) [de

  6. Is Green better than Blue? The Danish JHA opt-out and the Unilateral attempt to attrack highly skilled labour

    DEFF Research Database (Denmark)

    Wind, Marlene; Adamo, Silvia

    2015-01-01

    In 20–30 years Denmark will, just like the rest of the EU, be in need of an increasing number of highly skilled workers from outside the EU to sustain its welfare society. While the EU has adopted a common Blue Card aiming at making it possible for foreign workers to live and work in most of the EU......, Denmark has, due to its opt-out in Justice and Home Affairs, chosen its own Green Card Scheme. This article looks into this choice and compares the recent Danish attempt to attract high skilled workers with the Blue Card directive. It analyses the differences and similarities between the two schemes...... and investigates why initiatives to attract highly skilled workers have not been successful at either the Danish nor the European level....

  7. In Vivo Diffuse Optical Tomography and Fluorescence Molecular Tomography

    Directory of Open Access Journals (Sweden)

    Mingze Li

    2010-01-01

    Full Text Available Diffuse optical tomography (DOT and fluorescence molecular tomography (FMT are two attractive imaging techniques for in vivo physiological and psychological research. They have distinct advantages such as non-invasiveness, non-ionizing radiation, high sensitivity and longitudinal monitoring. This paper reviews the key components of DOT and FMT. Light propagation model, mathematical reconstruction algorithm, imaging instrumentation and medical applications are included. Future challenges and perspective on optical tomography are discussed.

  8. The new opt-out Dutch National Breast Implant Registry - Lessons learnt from the road to implementation.

    Science.gov (United States)

    Rakhorst, Hinne A; Mureau, Marc A M; Cooter, Rodney D; McNeil, John; van Hooff, Miranda; van der Hulst, René; Hommes, Juliette; Hoornweg, Marije; Moojen-Zaal, Laura; Liem, Patricia; Mathijssen, Irene M J

    2017-10-01

    An estimated 1-3% of all women in the Netherlands carry breast implants. Since the introduction five decades ago, problems with a variety of breast implants have emerged with direct consequences for the patients' health. Plastic surgeons worldwide reacted through campaigning for auditing on long-term implant quality, surgeon performance, and institutional outcomes in implant registries. Especially, the PIP implant scandal of 2010 demonstrated the paucity of epidemiological data and uncovered a weakness in our ability to even 'track and trace' patients. In addition, a recent report of the Dutch Institute of National Health showed a lack of compliance of 100% of breast implant producers to CE requirements. These arguments stress the need for an independent implant registry. Insufficient capture rates or dependence from the implant producers made the variety of national and international patient registries unreliable. The Dutch Breast Implant Registry (DBIR) is unique because it is an opt-out registry without the need for informed consent and thus a high capture rate. Furthermore, an estimated 95% of breast implants are implanted by board-certified plastic surgeons. Funding was received from a non-governmental organisation to increase the quality of health care in the Netherlands, and maintenance is gathered by 25 euros per implant inserted. This article describes the way the Dutch have set up their system, with special attention to the well-known hurdles of starting a patient registry. Examples include: funding, medical ethical issues, opt out system, benchmarking, quality assurance as well as governance and collaboration. The Dutch consider their experience and data shareware for others to be used globally to the benefit of patient safety and quality improvement. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  9. ExRET-Opt: An automated exergy/exergoeconomic simulation framework for building energy retrofit analysis and design optimisation

    International Nuclear Information System (INIS)

    García Kerdan, Iván; Raslan, Rokia; Ruyssevelt, Paul; Morillón Gálvez, David

    2017-01-01

    Highlights: • Development of a building retrofit-oriented exergoeconomic-based optimisation tool. • A new exergoeconomic cost-benefit indicator is developed for design comparison. • Thermodynamic and thermal comfort variables used as constraints and/or objectives. • Irreversibilities and exergetic cost for end-use processes are substantially reduced. • Robust methodology that should be pursued in everyday building retrofit practice. - Abstract: Energy simulation tools have a major role in the assessment of building energy retrofit (BER) measures. Exergoeconomic analysis and optimisation is a common practice in sectors such as the power generation and chemical processes, aiding engineers to obtain more energy-efficient and cost-effective energy systems designs. ExRET-Opt, a retrofit-oriented modular-based dynamic simulation framework has been developed by embedding a comprehensive exergy/exergoeconomic calculation method into a typical open-source building energy simulation tool (EnergyPlus). The aim of this paper is to show the decomposition of ExRET-Opt by presenting modules, submodules and subroutines used for the framework’s development as well as verify the outputs with existing research data. In addition, the possibility to perform multi-objective optimisation analysis based on genetic-algorithms combined with multi-criteria decision making methods was included within the simulation framework. This addition could potentiate BER design teams to perform quick exergy/exergoeconomic optimisation, in order to find opportunities for thermodynamic improvements along the building’s active and passive energy systems. The enhanced simulation framework is tested using a primary school building as a case study. Results demonstrate that the proposed simulation framework provide users with thermodynamic efficient and cost-effective designs, even under tight thermodynamic and economic constraints, suggesting its use in everyday BER practice.

  10. OptEase and TrapEase Vena Cava Filters: A Single-Center Experience in 258 Patients

    International Nuclear Information System (INIS)

    Onat, Levent; Ganiyusufoglu, Ali Kursat; Mutlu, Ayhan; Sirvanci, Mustafa; Duran, Cihan; Ulusoy, Onur Levent; Hamzaoglu, Azmi

    2009-01-01

    We aimed to evaluate the efficacy and safety of the OptEase and TrapEase (both from Cordis, Roden, Netherlands) vena cava filters in the prevention of pulmonary embolism (PE). Between May 2004 and December 2008, OptEase (permanent/retrievable; n = 228) or TrapEase (permanent; n = 30) vena cava filters were placed in 258 patients (160 female and 98 male; mean age 62 years [range 22 to 97]). Indications were as follows: prophylaxis for PE (n = 239), contraindication for anticoagulation in the presence of PE or DVT (n = 10), and development of PE or DVT despite anticoagulation (n = 9). Medical records were retrospectively reviewed for indications, clinical results, and procedure-related complications during placement and retrieval. Clinical PE did not develop in any of the patients. However, radiologic signs of segmental PE were seen in 6 of 66 patients with follow-up imaging data. Migration or fracture of the filter or cava perforation was not seen in any of the patients. Except for a single case of asymptomatic total cava thrombosis, no thrombotic occlusion was observed. One hundred forty-one patients were scheduled to undergo filter removal; however, 17 of them were not suitable for such based on venography evaluation. Removal was attempted in 124 patients and was successful in 115 of these (mean duration of retention 11 days [range 4 to 23]). Nine filters could not be removed. Permanent/retrievable vena cava filters are safe and effective devices for PE prophylaxis and for the management of venous thromboembolism by providing the option to be left in place.

  11. Time Domain Terahertz Axial Computed Tomography Non Destructive Evaluation, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase 2 project, we propose to develop, construct, and deliver to NASA a computed axial tomography time-domain terahertz (CT TD-THz) non destructive...

  12. Vinayaka : A Semi-Supervised Projected Clustering Method Using Differential Evolution

    OpenAIRE

    Satish Gajawada; Durga Toshniwal

    2012-01-01

    Differential Evolution (DE) is an algorithm for evolutionary optimization. Clustering problems have beensolved by using DE based clustering methods but these methods may fail to find clusters hidden insubspaces of high dimensional datasets. Subspace and projected clustering methods have been proposed inliterature to find subspace clusters that are present in subspaces of dataset. In this paper we proposeVINAYAKA, a semi-supervised projected clustering method based on DE. In this method DE opt...

  13. Mesenteric panniculitis: computed tomography aspects

    International Nuclear Information System (INIS)

    Moreira, Luiza Beatriz Melo; Alves, Jose Ricardo Duarte; Marchiori, Edson; Pinheiro, Ricardo Andrade; Melo, Alessandro Severo Alves de; Noro, Fabio

    2001-01-01

    Mesenteric panniculitis is an inflammatory process that represents the second stage of a rare progressive disease involving the adipose tissue of the mesentery. Imaging methods used in the diagnosis of mesenteric panniculitis include barium studies, ultrasonography, computed tomography and magnetic resonance imaging. Computed tomography is important for both, diagnosis and evaluation of the extension of the disease and treatment monitoring. Computed tomography findings may vary according to the stage of the disease and the amount of inflammatory material or fibrosis. There is also good correlation between the computed tomography and anatomical pathology findings. The authors studied 10 patients with mesenteric panniculitis submitted to computed tomography. Magnetic resonance imaging was also performed in one patient. In all patients, computed tomography revealed a heterogeneous mass in the mesentery with density of fat, interspersed with areas of soft tissue density and dilated vessels. (author)

  14. Minimum Fisher Tikhonov Regularization Adapted to Real-Time Tomography

    Czech Academy of Sciences Publication Activity Database

    Löffelmann, Viktor; Mlynář, Jan; Imríšek, Martin; Mazon, D.; Jardin, A.; Weinzettl, Vladimír; Hron, Martin

    2016-01-01

    Roč. 69, č. 2 (2016), s. 505-513 ISSN 1536-1055 R&D Projects: GA MŠk LG14002; GA MŠk(CZ) LM2011021 Institutional support: RVO:61389021 Keywords : tokamak * tomography * real - time Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.578, year: 2016

  15. Tile-Packing Tomography Is NP-hard

    DEFF Research Database (Denmark)

    Chrobak, Marek; Dürr, Christoph; Guíñez, Flavio

    2010-01-01

    Discrete tomography deals with reconstructing finite spatial objects from their projections. The objects we study in this paper are called tilings or tile-packings, and they consist of a number of disjoint copies of a fixed tile, where a tile is defined as a connected set of grid points. A row...

  16. Improving Public Schools through the Dissent of Parents: Opting out of Tests, Demanding Alternative Curricula, Invoking Parent Trigger Laws, and Withdrawing Entirely

    Science.gov (United States)

    Stitzlein, Sarah M.

    2015-01-01

    Some parents and caregivers, frustrated by low academic performance of their local school, emphasis on testing, or the content of the curriculum, have worked independently or formed parent groups to speak out and demand improvements. Parents and families enact solutions such as opting out of tests, developing alternative curricula, invoking parent…

  17. 16 CFR 316.5 - Prohibition on charging a fee or imposing other requirements on recipients who wish to opt out.

    Science.gov (United States)

    2010-01-01

    ... other than the recipient's electronic mail address and opt-out preferences, or take any other steps except sending a reply electronic mail message or visiting a single Internet Web page, in order to: (a) Use a return electronic mail address or other Internet-based mechanism, required by 15 U.S.C. 7704(a...

  18. Method of multiplanar emission tomography and apparatus therefor

    International Nuclear Information System (INIS)

    Gottschalk, S.C.; Smith, K.A.; Wake, R.H.

    1981-01-01

    A method of emission tomography using a gamma camera and a rotating collimator having an array of a large number of slanted, small diameter holes. A planar projection corresponding to each angular orientation assumed by the collimator is recorded. From these series of planar projections, a three-dimensional simulation model is reconstructed by an iterative algorithm which approximates the emitting object. The simulated model comprises multiple separable planes

  19. Scanning Microwave Induced Acoustic Tomography

    National Research Council Canada - National Science Library

    Wang, Lihong V

    2002-01-01

    .... Specifically, our accomplishments include (1) an exact and an approximate time-domain reconstruction algorithm for thermoacoustic tomography in a spherical geometry was derived and published, (2...

  20. Evolution/Creationism Controversy: Analysis of Past and Current Policies in Public Schools and the Practice of Allowing Students to Opt Out of Learning Evolution Concepts

    Science.gov (United States)

    Speake, Jacquelyn Hoffmann

    2011-07-01

    Recent anti-evolution legislation, in the form of Academic Freedom bills, has been introduced in many state legislatures over the last three years. The language in the proposed Academic Freedom bills may allow different interpretations of what can be taught in the science classrooms, and possibly spur parents to take advantage of their perceived parental rights to request their child be opted-out of class when the scientific theory of evolution is taught. Five research questions guided the analysis of participant responses to questions and perception statements focusing on secondary school administrators' actions, perceptions, and awareness as they relate to their decision to allow or not allow a student to opt out of academics, specifically evolution, through the collection of data using a web-based survey. Opt out policies are typically invoked to excuse students from activities to which they or their parents may have religious objections (Scott & Branch, 2008). Florida statutes allow parents to opt out their child from human sexuality and animal dissection. The population consisted of 281 Florida public secondary school administrators, who were divided into two subgroups based on whether they have allowed or would allow a student to opt out of evolution, or have not allowed or would not allow a student to opt out of class when the scientific theory of evolution is taught. Results found that over 70% of the administrators who completed the survey have allowed or would allow parents to opt out their child from learning about the scientific theory of evolution. There was a significant relationship between the decision to allow opt out and the following variables: (a) Free and Reduced Lunch population, (b) grade level served, (c) support for teaching evolution and alternative theories, and (d) the perception that parent rights supersede state statute requiring students to learn evolution. In Florida, any scientific concept that is based on empirical evidence is

  1. Projection radiography. Chapter 6

    Energy Technology Data Exchange (ETDEWEB)

    Poletti, J. L. [UNITEC Institute of Technology, Auckland (New Zealand)

    2014-09-15

    In its simplest form, X ray imaging is the collection of attenuation shadows that are projected from an ideal X ray point source on to an image receptor. This simple form is true for all X ray imaging modalities, including complex ones that involve source and receptor movement, such as computed tomography (CT). This simplified view, however, is made vastly more complex by the non-ideal point source, by the consequences of projecting a 3-D object on to a 2-D detector and by the presence of scattered radiation, generated within the patient, which will degrade any image that is captured.

  2. Positron Emission Tomography (PET)

    International Nuclear Information System (INIS)

    Welch, M.J.

    1990-01-01

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET. 22 figs

  3. Compressive Phase Contrast Tomography

    International Nuclear Information System (INIS)

    Maia, Filipe; MacDowell, Alastair; Marchesini, Stefano; Padmore, Howard A.; Parkinson, Dula Y.; Pien, Jack; Schirotzek, Andre; Yang, Chao

    2010-01-01

    When x-rays penetrate soft matter, their phase changes more rapidly than their amplitude. Interference effects visible with high brightness sources creates higher contrast, edge enhanced images. When the object is piecewise smooth (made of big blocks of a few components), such higher contrast datasets have a sparse solution. We apply basis pursuit solvers to improve SNR, remove ring artifacts, reduce the number of views and radiation dose from phase contrast datasets collected at the Hard X-Ray Micro Tomography Beamline at the Advanced Light Source. We report a GPU code for the most computationally intensive task, the gridding and inverse gridding algorithm (non uniform sampled Fourier transform).

  4. Positron Emission Tomography (PET)

    Energy Technology Data Exchange (ETDEWEB)

    Welch, M.J.

    1990-01-01

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET. 22 figs.

  5. Recent RI tomography

    International Nuclear Information System (INIS)

    Katsuyama, Naofumi; Kawakami, Kenshi

    1979-01-01

    In this paper, new equipments for radionuclide tomography and recent radiopharmaceuticals with positron emission are described. Positron CT is very usefull for functional imaging. Those nucleides 11 C, 13 N and 15 O have been studied for their sake, but used as a usefull tool as tracer elements for the basic research in the fields of chemistry, bio-chemistry, biology and medicine. Also they have been utilized in the diagnosis of diseases, particularly in the non-invasive and dynamic assessment of metabolic and functional disorders in the patients. We will also describe the clinical usefullness of a commercial scanner such as the Anger multiplane tomographic scanner (PHO/CON). (author)

  6. Gantry for computed tomography

    International Nuclear Information System (INIS)

    Kelman, A.L.; Peterson, T.E.

    1981-01-01

    A novel design of gantry for use in computed tomography is described in detail. In the new gantry, curved tracks are mounted to the laterally spaced apart sides of the frame which rotates and carries the detector and X-ray source. This permits the frame to be tilted either side of vertical enabling angular slices of body layers to be viewed and allows simplification of the algorithm which the computer uses for image reconstruction. The tracks are supported on rollers which carry the substantial weight. Explicit engineering details are presented especially of the ball bearing races used in the rotation. (U.K.)

  7. Gantry for computed tomography

    International Nuclear Information System (INIS)

    Brandt, R.T.; Hein, P.W.

    1981-01-01

    A novel design of gantry for use in computed tomography is described in detail. In the new gantry, curved tracks are mounted to the laterally spaced apart sides of the frame which rotates and carries the detector and X-ray source. This permits the frame to be tilted either side of vertical enabling angular slices of body layers to be viewed and allows simplification of the algorithm which the computer uses for image reconstruction. The tracks are supported on rollers which carry the substantial weight. Explicit engineering details are presented. (U.K.)

  8. Method for computed tomography

    International Nuclear Information System (INIS)

    Wagner, W.

    1980-01-01

    In transversal computer tomography apparatus, in which the positioning zone in which the patient can be positioned is larger than the scanning zone in which a body slice can be scanned, reconstruction errors are liable to occur. These errors are caused by incomplete irradiation of the body during examination. They become manifest not only as an incorrect image of the area not irradiated, but also have an adverse effect on the image of the other, completely irradiated areas. The invention enables reduction of these errors

  9. Positron Emission Tomography (PET)

    Science.gov (United States)

    Welch, M. J.

    1990-01-01

    Positron emission tomography (PET) assesses biochemical processes in the living subject, producing images of function rather than form. Using PET, physicians are able to obtain not the anatomical information provided by other medical imaging techniques, but pictures of physiological activity. In metaphoric terms, traditional imaging methods supply a map of the body's roadways, its, anatomy; PET shows the traffic along those paths, its biochemistry. This document discusses the principles of PET, the radiopharmaceuticals in PET, PET research, clinical applications of PET, the cost of PET, training of individuals for PET, the role of the United States Department of Energy in PET, and the futures of PET.

  10. Solar Stereoscopy and Tomography

    Directory of Open Access Journals (Sweden)

    Markus J. Aschwanden

    2011-10-01

    Full Text Available We review stereoscopic and tomographic methods used in the solar corona, including ground-based and space-based measurements, using solar rotation or multiple spacecraft vantage points, in particular from the STEREO mission during 2007--2010. Stereoscopic and tomographic observations in the solar corona include large-scale structures, streamers, active regions, coronal loops, loop oscillations, acoustic waves in loops, erupting filaments and prominences, bright points, jets, plumes, flares, CME source regions, and CME-triggered global coronal waves. Applications in the solar interior (helioseismic tomography and reconstruction and tracking of CMEs from the outer corona and into the heliosphere (interplanetary CMEs are not included.

  11. Radial reflection diffraction tomography

    Science.gov (United States)

    Lehman, Sean K.

    2012-12-18

    A wave-based tomographic imaging method and apparatus based upon one or more rotating radially outward oriented transmitting and receiving elements have been developed for non-destructive evaluation. At successive angular locations at a fixed radius, a predetermined transmitting element can launch a primary field and one or more predetermined receiving elements can collect the backscattered field in a "pitch/catch" operation. A Hilbert space inverse wave (HSIW) algorithm can construct images of the received scattered energy waves using operating modes chosen for a particular application. Applications include, improved intravascular imaging, bore hole tomography, and non-destructive evaluation (NDE) of parts having existing access holes.

  12. Positron emission tomography

    CERN Document Server

    Paans, A M J

    2006-01-01

    Positron Emission Tomography (PET) is a method for measuring biochemical and physiological processes in vivo in a quantitative way by using radiopharmaceuticals labelled with positron emitting radionuclides such as 11C, 13N, 15O and 18F and by measuring the annihilation radiation using a coincidence technique. This includes also the measurement of the pharmacokinetics of labelled drugs and the measurement of the effects of drugs on metabolism. Also deviations of normal metabolism can be measured and insight into biological processes responsible for diseases can be obtained. At present the combined PET/CT scanner is the most frequently used scanner for whole-body scanning in the field of oncology.

  13. Positron emission tomography

    International Nuclear Information System (INIS)

    Paans, A.M.J.

    1981-01-01

    Positron emitting radiopharmaceuticals have special applications in in-vivo studies of biochemical processes. The combination of a cyclotron for the production of radionuclides and a positron emission tomograph for the registration of the distribution of radioactivity in the body enables the measurement of local radioactivity concentration in tissues, and opens up new possibilities in the diagnosis and examination of abnormalities in the metabolism. The principles and procedures of positron emission tomography are described and the necessary apparatus considered, with emphasis on the positron camera. The first clinical applications using 55 Co bloemycine for tumor detection are presented. (C.F.)

  14. Dynamic tomography in dentistry

    International Nuclear Information System (INIS)

    Richards, A.G.

    1976-01-01

    Dynamic tomography is a procedure in which a sandwich of eight underexposed radiographs is utilized to display sharp images of details lying in a thin layer at any chosen depth within a subject. When the sandwich of films is viewed by transmitted light, the location of this chosen layer can be moved up or down within the subject by simply mechanically moving the radiographs in a precise manner relative to each other. The amount of radiation used in exposing the eight radiographs is the same as would be used to fully expose two normal radiographs

  15. Dosimetry in computed tomography

    International Nuclear Information System (INIS)

    Andisco, D.; Blanco, S.; Buzzia, A.E.

    2014-01-01

    Objective: The amount of computed tomography (CT) studies that are performed each year in the world is growing exponentially mainly due to the incorporation of multislice CT that allows studies in a few seconds. But, despite the benefit received by patients with the diagnosis, radiation dose is a concern in the professional community and it has be reduced as much as reasonably possible. This article describes the main dosimetric CT units used in order to work with this practice easily, using the values that provide modern equipment and internationally known reference levels. (authors) [es

  16. Practical adaptive quantum tomography

    Science.gov (United States)

    Granade, Christopher; Ferrie, Christopher; Flammia, Steven T.

    2017-11-01

    We introduce a fast and accurate heuristic for adaptive tomography that addresses many of the limitations of prior methods. Previous approaches were either too computationally intensive or tailored to handle special cases such as single qubits or pure states. By contrast, our approach combines the efficiency of online optimization with generally applicable and well-motivated data-processing techniques. We numerically demonstrate these advantages in several scenarios including mixed states, higher-dimensional systems, and restricted measurements. http://cgranade.com complete data and source code for this work are available online [1], and can be previewed at https://goo.gl/koiWxR.

  17. Cone beam tomography of the heart using single-photon emission-computed tomography

    International Nuclear Information System (INIS)

    Gullberg, G.T.; Christian, P.E.; Zeng, G.L.; Datz, F.L.; Morgan, H.T.

    1991-01-01

    The authors evaluated cone beam single-photon emission-computed tomography (SPECT) of the heart. A new cone beam reconstruction algorithm was used to reconstruct data collected from short scan acquisitions (of slightly more than 180 degrees) of a detector anteriorally traversing a noncircular orbit. The less than 360 degrees acquisition was used to minimize the attenuation artifacts that result from reconstructing posterior projections of 201T1 emissions from the heart. The algorithm includes a new method for reconstructing truncated projections of background tissue activity that eliminates reconstruction ring artifacts. Phantom and patient results are presented which compare a high-resolution cone beam collimator (50-cm focal length; 6.0-mm full width at half maximum [FWHM] at 10 cm) to a low-energy general purpose (LEGP) parallel hole collimator (8.2-mm FWHM at 10 cm) which is 1.33 times more sensitive. The cone beam tomographic results are free of reconstruction artifacts and show improved spatial and contrast resolution over that obtained with the LEGP parallel hole collimator. The limited angular sampling restrictions and truncation problems associated with cone beam tomography do not deter from obtaining diagnostic information. However, even though these preliminary results are encouraging, a thorough clinical study is still needed to investigate the specificity and sensitivity of cone beam tomography

  18. Atlanta Gas Light opts for an in-house AM/FM

    International Nuclear Information System (INIS)

    Hull, S.R.

    1993-01-01

    Atlanta Gas Light Co. has completed facilities conversion for the first of nine planned implementations of its automated mapping/facilities management mapping/facilities management system, the Facilities and Land Base Automated Mapping Environment or FLAME. Facilities conversion is generally the most costly and time-consuming phase of an AM/FM project. Many companies decide to rely totally on outside expertise for this phase because of the complexity of the process an the resources required to complete it. Atlanta Gas Light decided to take an alternate approach by performing the facilities conversion process in-house for the first implementation, than having an outside vendor carrying out a future implementation and compare the two

  19. Auroral Tomography Workshop, Proceedings

    International Nuclear Information System (INIS)

    Steen, Aa.

    1993-08-01

    In ionospheric and atmospheric physics the importance of multi-station imaging has grown as a consequence of the availability of scientific grade CCD cameras with digital output and affordable massive computing power. Tomographic inversion techniques are used in many different areas, e.g. medicine, plasma research and space physics. The tomography workshop was announced to gather a limited group of people interested in auroral tomography or tomographic inversion methods in general. ALIS (Auroral Large Imaging System) is a multi-station ground-based system developed primarily for three-dimensional auroral imaging, however other non-auroral objects can be studied with ALIS, e.g. stratospheric clouds. Several of the contributions in the workshop dealt with problems related to geometries similar to the ALIS-configuration. The Proceedings contain written contributions received either in abstract form or as full papers. The Proceedings also contain contributions intended for the Workshop but not presented due to the absence of the speaker. Separate abstracts have been prepared for 15 of the 17 papers

  20. Positron emission tomography. Positronemisionstomografi

    Energy Technology Data Exchange (ETDEWEB)

    Bolwig, T G; Haunsoe, S; Dahlgaard Hove, J; Hesse, B; Hoejgard, L; Jensen, M; Paulson, O B; Hastrup Svendsen, J; Soelvsten Soerensen, S

    1994-10-01

    Positron emission tomography (PET) is a method for quantitative imaging of regional physiological and biochemical parameters. Positron emitting radioactive isotopes can be produced by a cyclotron, eg. the biologically important carbon ([sup 11]C), oxygen ([sup 15]O), and nitrogen ([sup 13]N) elements. With the tomographic principles of the PET scanner the quantitative distribution of the administered isotopes can be determined and images can be provided as well as dynamic information on blood flow, metabolism and receptor function. In neurology PET has been used for investigations on numerous physiological processes in the brain: circulation, metabolism and receptor studies. In Parkinson's disease PET studies have been able to localize the pathology specifically, and in early stroke PET technique can outline focal areas with living but non-functioning cells, and this could make it possible to intervene in this early state. With positron emission tomography a quantitative evaluation of myocardial blood flow, glucose and fatty acid metabolism can be made as well as combined assessments of blood flow and metabolism. Combined studies of blood flow and metabolism can determine whether myocardial segments with abnormal motility consist of necrotic or viable tissue, thereby delineating effects of revascularisation. In the future it will probably be possible to characterize the myocardial receptor status in different cardiac diseases. The PET technique is used in oncology for clinical as well as more basic research on tumor perfusion and metabolism. Further, tumor uptake of positron labelled cytotoxic drugs might predict the clinical benefit of treatment. (au) (19 refs.).

  1. Waste inspection tomography (WIT)

    Energy Technology Data Exchange (ETDEWEB)

    Bernardi, R.T. [Bio-Imaging Research, Inc., Lincolnshire, IL (United States)

    1995-10-01

    Waste Inspection Tomography (WIT) provides mobile semi-trailer mounted nondestructive examination (NDE) and assay (NDA) for nuclear waste drum characterization. WIT uses various computed tomography (CT) methods for both NDE and NDA of nuclear waste drums. Low level waste (LLW), transuranic (TRU), and mixed radioactive waste can be inspected and characterized without opening the drums. With externally transmitted x-ray NDE techniques, WIT has the ability to identify high density waste materials like heavy metals, define drum contents in two- and three-dimensional space, quantify free liquid volumes through density and x-ray attenuation coefficient discrimination, and measure drum wall thickness. With waste emitting gamma-ray NDA techniques, WIT can locate gamma emitting radioactive sources in two- and three-dimensional space, identify gamma emitting, isotopic species, identify the external activity levels of emitting gamma-ray sources, correct for waste matrix attenuation, provide internal activity approximations, and provide the data needed for waste classification as LLW or TRU.

  2. Transverse tomography and radiotherapy

    International Nuclear Information System (INIS)

    Leer, J.W.H.

    1982-01-01

    This study was intended to delineate the indications for radiotherapy treatment-planning with the help of computerized axial tomography (C.T.) and transverse analog tomography (T.A.T.). Radiotherapy localisation procedures with the conventional method (simulator), with the CT-scanner and with the transverse analog tomograph (T.A.T., Simtomix, Oldelft) were compared. As criterium for evaluation differences in reconstruction drawing based on these methods were used. A certain method was judged ''superior'' to another if the delineation of the target volume was more accurate, if a better impression was gained of the site of (for irradiation) organs at risk, or if the localisation could only be performed with that method. The selected group of patients consisted of 120 patients for whom a reconstruction drawing in the transverse plane was made according to the treatment philosophy. In this group CT-assisted localisation was judged on 68 occasions superior to the conventional method. In a number of cases it was found that a ''standard'' change in a standard target volume, on the base of augmented anatomical knowledge, made the conventional method sufficient. The use of CT-scanner for treatment planning was estimated. For ca. 270/1000 new patients a CT-scan is helpful (diagnostic scan), for 140 of them the scan is necessary (planning scan). The quality of the anatomical information obtained with the T.A.T. does not yet fall within acceptable limits, but progress has been made. (Auth.)

  3. Positron emission tomography

    International Nuclear Information System (INIS)

    Bolwig, T.G.; Haunsoe, S.; Dahlgaard Hove, J.; Hesse, B.; Hoejgard, L.; Jensen, M.; Paulson, O.B.; Hastrup Svendsen, J.; Soelvsten Soerensen, S.

    1994-01-01

    Positron emission tomography (PET) is a method for quantitative imaging of regional physiological and biochemical parameters. Positron emitting radioactive isotopes can be produced by a cyclotron, eg. the biologically important carbon ( 11 C), oxygen ( 15 O), and nitrogen ( 13 N) elements. With the tomographic principles of the PET scanner the quantitative distribution of the administered isotopes can be determined and images can be provided as well as dynamic information on blood flow, metabolism and receptor function. In neurology PET has been used for investigations on numerous physiological processes in the brain: circulation, metabolism and receptor studies. In Parkinson's disease PET studies have been able to localize the pathology specifically, and in early stroke PET technique can outline focal areas with living but non-functioning cells, and this could make it possible to intervene in this early state. With positron emission tomography a quantitative evaluation of myocardial blood flow, glucose and fatty acid metabolism can be made as well as combined assessments of blood flow and metabolism. Combined studies of blood flow and metabolism can determine whether myocardial segments with abnormal motility consist of necrotic or viable tissue, thereby delineating effects of revascularisation. In the future it will probably be possible to characterize the myocardial receptor status in different cardiac diseases. The PET technique is used in oncology for clinical as well as more basic research on tumor perfusion and metabolism. Further, tumor uptake of positron labelled cytotoxic drugs might predict the clinical benefit of treatment. (au) (19 refs.)

  4. Waste inspection tomography (WIT)

    International Nuclear Information System (INIS)

    Bernardi, R.T.

    1995-01-01

    Waste Inspection Tomography (WIT) provides mobile semi-trailer mounted nondestructive examination (NDE) and assay (NDA) for nuclear waste drum characterization. WIT uses various computed tomography (CT) methods for both NDE and NDA of nuclear waste drums. Low level waste (LLW), transuranic (TRU), and mixed radioactive waste can be inspected and characterized without opening the drums. With externally transmitted x-ray NDE techniques, WIT has the ability to identify high density waste materials like heavy metals, define drum contents in two- and three-dimensional space, quantify free liquid volumes through density and x-ray attenuation coefficient discrimination, and measure drum wall thickness. With waste emitting gamma-ray NDA techniques, WIT can locate gamma emitting radioactive sources in two- and three-dimensional space, identify gamma emitting, isotopic species, identify the external activity levels of emitting gamma-ray sources, correct for waste matrix attenuation, provide internal activity approximations, and provide the data needed for waste classification as LLW or TRU

  5. Eurasia: The Rivalry of Global Integration Projects

    Directory of Open Access Journals (Sweden)

    Olesia Kobenko

    2016-05-01

    Full Text Available The article reveals the Eurasian integration projects as major drivers of world globalization. Eurasian regionalism seems to be gaining attention in the scientific literature. Under the current political circumstance many regions are accelerating integration and many countries are opting for regional associations as a mechanism to help them overcome the global recession. Moreover, the global political leaders , some developed countries - the U.S., China, and the European Union (EU are interested to set up regional economic blocs such as Eurasian Economic Union (The EEU, the China's project 'One Belt One Road', the U.S's projects - The Trans-Pacific Partnership (TPP and The Transatlantic Trade and Investment Partnership (TTIP. The goal of this paper is to introduce a number of integration initiatives and to analyze the current strategies of Eurasian regionalism.

  6. [Computed tomography of the heart

    DEFF Research Database (Denmark)

    Kristensen, T.S.; Kofoed, K.F.; der, Recke P. von

    2009-01-01

    Noninvasive evaluation of the coronary arteries by multi-detector row computed tomography is a promising new alternative to conventional invasive coronary angiography. This article describes the technical background, methods, limitations and clinical applications and reviews current literature...... that compares the diagnostic accuracy of multi-detector row computed tomography with that of coronary angiography Udgivelsesdato: 2009/4/6...

  7. Absorbed and effective dose from spiral and computed tomography for the dental implant planning

    International Nuclear Information System (INIS)

    Hong, Beong Hee; Han, Won Jeong; Kim, Eun Kyung

    2001-01-01

    To evaluate the absorbed and effective doses of spiral and computed tomography for the dental implant planning. For radiographic projection. TLD chips were placed in 22 sites of humanoid phantom to record the exposure to skin and the mean absorbed dose to bone marrow, thyroid, pituitary, parotid and submandibular glands and nesophages. Effective dose was calculated, using the method suggested by Frederiksen at al.. Patient situations of a single tooth gap in upper and lower midline region, edentulous maxilla and mandible were simulated for spiral tomography. 35 axial slices (maxilla) and 40 axial slices (mandible) with low and standard dose setting were used for computed tomography. All the radiographic procedures were repeated three times. The mean effective dose in case of maxilla was 0.865 mSv, 0.452 mSv, 0.136 mSv and 0.025 mSv, in spiral tomography of complete edentulous maxilla, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). That in case of mandible was 0.614 mSv, 0.448 mSv, 0.137 mSv and 0.036 mSv, in spiral tomography of complete edentulous mandible, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). Based on these results, it can be concluded that low mAs computed tomography is recommended instead of spiral tomography for the complete edentulous maxilla and mandible dental implant treatment planning

  8. Computerized tomography of the mandibular joints and masticatory muscles

    International Nuclear Information System (INIS)

    Huels, A.B.

    1981-01-01

    A methodology for computerized tomography of the mandibular joints was developed and applied in 80 test persons. Imaging of the mandibular joints is possible with a tomographic technique with 5 mm-overlap, full utilisation of the enlargement capacity of the imaging device, and combined use of transversal and coronary tomography. The method yields full latero-medial, cranio-caudal and anterior-posterior views of the condyle and fossa contours, free of interferences and of distortions caused by the projection. Positional diagnoses are thus possible as well as diagnoses of pathological structural changes. (orig./MG) [de

  9. Chlamydia trachomatis co-opts GBF1 and CERT to acquire host sphingomyelin for distinct roles during intracellular development.

    Directory of Open Access Journals (Sweden)

    Cherilyn A Elwell

    2011-09-01

    Full Text Available The strain designated Chlamydia trachomatis serovar that was used for experiments in this paper is Chlamydia muridarum, a species closely related to C. trachomatis (and formerly termed the Mouse Pneumonitis strain of C. trachomatis. [corrected]. The obligate intracellular pathogen Chlamydia trachomatis replicates within a membrane-bound inclusion that acquires host sphingomyelin (SM, a process that is essential for replication as well as inclusion biogenesis. Previous studies demonstrate that SM is acquired by a Brefeldin A (BFA-sensitive vesicular trafficking pathway, although paradoxically, this pathway is dispensable for bacterial replication. This finding suggests that other lipid transport mechanisms are involved in the acquisition of host SM. In this work, we interrogated the role of specific components of BFA-sensitive and BFA-insensitive lipid trafficking pathways to define their contribution in SM acquisition during infection. We found that C. trachomatis hijacks components of both vesicular and non-vesicular lipid trafficking pathways for SM acquisition but that the SM obtained from these separate pathways is being utilized by the pathogen in different ways. We show that C. trachomatis selectively co-opts only one of the three known BFA targets, GBF1, a regulator of Arf1-dependent vesicular trafficking within the early secretory pathway for vesicle-mediated SM acquisition. The Arf1/GBF1-dependent pathway of SM acquisition is essential for inclusion membrane growth and stability but is not required for bacterial replication. In contrast, we show that C. trachomatis co-opts CERT, a lipid transfer protein that is a key component in non-vesicular ER to trans-Golgi trafficking of ceramide (the precursor for SM, for C. trachomatis replication. We demonstrate that C. trachomatis recruits CERT, its ER binding partner, VAP-A, and SM synthases, SMS1 and SMS2, to the inclusion and propose that these proteins establish an on-site SM biosynthetic

  10. Industrial Computed Tomography using Proximal Algorithm

    KAUST Repository

    Zang, Guangming

    2016-04-14

    In this thesis, we present ProxiSART, a flexible proximal framework for robust 3D cone beam tomographic reconstruction based on the Simultaneous Algebraic Reconstruction Technique (SART). We derive the proximal operator for the SART algorithm and use it for minimizing the data term in a proximal algorithm. We show the flexibility of the framework by plugging in different powerful regularizers, and show its robustness in achieving better reconstruction results in the presence of noise and using fewer projections. We compare our framework to state-of-the-art methods and existing popular software tomography reconstruction packages, on both synthetic and real datasets, and show superior reconstruction quality, especially from noisy data and a small number of projections.

  11. Magnified Weak Lensing Cross Correlation Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, Melville P., Clowe, Douglas I.

    2010-11-30

    This project carried out a weak lensing tomography (WLT) measurement around rich clusters of galaxies. This project used ground based photometric redshift data combined with HST archived cluster images that provide the WLT and cluster mass modeling. The technique has already produced interesting results (Guennou et al, 2010,Astronomy & Astrophysics Vol 523, page 21, and Clowe et al, 2011 to be submitted). Guennou et al have validated that the necessary accuracy can be achieved with photometric redshifts for our purposes. Clowe et al titled "The DAFT/FADA survey. II. Tomographic weak lensing signal from 10 high redshift clusters," have shown that for the **first time** via this purely geometrical technique, which does not assume a standard rod or candle, that a cosmological constant is **required** for flat cosmologies. The intent of this project is not to produce the best constraint on the value of the dark energy equation of state, w. Rather, this project is to carry out a sustained effort of weak lensing tomography that will naturally feed into the near term Dark Energy Survey (DES) and to provide invaluable mass calibration for that project. These results will greatly advance a key cosmological method which will be applied to the top-rated ground-based project in the Astro2020 decadal survey, LSST. Weak lensing tomography is one of the key science drivers behind LSST. CO-I Clowe is on the weak lensing LSST committee, and senior scientist on this project, at FNAL James Annis, plays a leading role in the DES. This project has built on successful proposals to obtain ground-based imaging for the cluster sample. By 1 Jan, it is anticipated the project will have accumulated complete 5-color photometry on 30 (or about 1/3) of the targeted cluster sample (public webpage for the survey is available at http://cencos.oamp.fr/DAFT/ and has a current summary of the observational status of various clusters). In all, the project has now been awarded the equivalent of over 60

  12. EDITORIAL: Industrial Process Tomography

    Science.gov (United States)

    Anton Johansen, Geir; Wang, Mi

    2008-09-01

    There has been tremendous development within measurement science and technology over the past couple of decades. New sensor technologies and compact versatile signal recovery electronics are continuously expanding the limits of what can be measured and the accuracy with which this can be done. Miniaturization of sensors and the use of nanotechnology push these limits further. Also, thanks to powerful and cost-effective computer systems, sophisticated measurement and reconstruction algorithms previously only accessible in advanced laboratories are now available for in situ online measurement systems. The process industries increasingly require more process-related information, motivated by key issues such as improved process control, process utilization and process yields, ultimately driven by cost-effectiveness, quality assurance, environmental and safety demands. Industrial process tomography methods have taken advantage of the general progress in measurement science, and aim at providing more information, both quantitatively and qualitatively, on multiphase systems and their dynamics. The typical approach for such systems has been to carry out one local or bulk measurement and assume that this is representative of the whole system. In some cases, this is sufficient. However, there are many complex systems where the component distribution varies continuously and often unpredictably in space and time. The foundation of industrial tomography is to conduct several measurements around the periphery of a multiphase process, and use these measurements to unravel the cross-sectional distribution of the process components in time and space. This information is used in the design and optimization of industrial processes and process equipment, and also to improve the accuracy of multiphase system measurements in general. In this issue we are proud to present a selection of the 145 papers presented at the 5th World Congress on Industrial Process Tomography in Bergen

  13. Quantitative tomography simulations and reconstruction algorithms

    International Nuclear Information System (INIS)

    Martz, H.E.; Aufderheide, M.B.; Goodman, D.; Schach von Wittenau, A.; Logan, C.; Hall, J.; Jackson, J.; Slone, D.

    2000-01-01

    X-ray, neutron and proton transmission radiography and computed tomography (CT) are important diagnostic tools that are at the heart of LLNL's effort to meet the goals of the DOE's Advanced Radiography Campaign. This campaign seeks to improve radiographic simulation and analysis so that radiography can be a useful quantitative diagnostic tool for stockpile stewardship. Current radiographic accuracy does not allow satisfactory separation of experimental effects from the true features of an object's tomographically reconstructed image. This can lead to difficult and sometimes incorrect interpretation of the results. By improving our ability to simulate the whole radiographic and CT system, it will be possible to examine the contribution of system components to various experimental effects, with the goal of removing or reducing them. In this project, we are merging this simulation capability with a maximum-likelihood (constrained-conjugate-gradient-CCG) reconstruction technique yielding a physics-based, forward-model image-reconstruction code. In addition, we seek to improve the accuracy of computed tomography from transmission radiographs by studying what physics is needed in the forward model. During FY 2000, an improved version of the LLNL ray-tracing code called HADES has been coupled with a recently developed LLNL CT algorithm known as CCG. The problem of image reconstruction is expressed as a large matrix equation relating a model for the object being reconstructed to its projections (radiographs). Using a constrained-conjugate-gradient search algorithm, a maximum likelihood solution is sought. This search continues until the difference between the input measured radiographs or projections and the simulated or calculated projections is satisfactorily small

  14. A randomised controlled trial of Outpatient versus inpatient Polyp Treatment (OPT) for abnormal uterine bleeding.

    Science.gov (United States)

    Clark, T Justin; Middleton, Lee J; Cooper, Natalie Am; Diwakar, Lavanya; Denny, Elaine; Smith, Paul; Gennard, Laura; Stobert, Lynda; Roberts, Tracy E; Cheed, Versha; Bingham, Tracey; Jowett, Sue; Brettell, Elizabeth; Connor, Mary; Jones, Sian E; Daniels, Jane P

    2015-07-01

    that outpatient polypectomy was at most 18% worse, in relative terms, than inpatient treatment, within the 25% margin of non-inferiority set at the outset of the study. By 1 and 2 years the corresponding proportions were similar producing RRs close to unity. There was no evidence that the treatment effect differed according to any of the predefined subgroups when treatments by variable interaction parameters were examined. Failure to completely remove polyps was higher (19% vs. 7%; RR 2.5, 95% CI 1.5 to 4.1) with outpatient polypectomy. Procedure acceptability was reduced with outpatient compared with inpatient polyp treatment (83% vs. 92%; RR 0.90, 95% CI 0.84 to 0.97). There were no significant differences in quality of life. The incremental cost-effectiveness ratios at 6 and 12 months for inpatient treatment were £1,099,167 and £668,800 per additional QALY, respectively. When treating women with AUB associated with uterine polyps, outpatient polypectomy was non-inferior to inpatient polypectomy at 6 and 12 months, and relatively cost-effective. However, patients need to be aware that failure to remove a polyp is more likely with outpatient polypectomy and procedure acceptability lower. Current Controlled Trials ISRCTN 65868569. This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 61. See the NIHR Journals Library website for further project information.

  15. Hemifield columns co-opt ocular dominance column structure in human achiasma.

    Science.gov (United States)

    Olman, Cheryl A; Bao, Pinglei; Engel, Stephen A; Grant, Andrea N; Purington, Chris; Qiu, Cheng; Schallmo, Michael-Paul; Tjan, Bosco S

    2018-01-01

    In the absence of an optic chiasm, visual input to the right eye is represented in primary visual cortex (V1) in the right hemisphere, while visual input to the left eye activates V1 in the left hemisphere. Retinotopic mapping In V1 reveals that in each hemisphere left and right visual hemifield representations are overlaid (Hoffmann et al., 2012). To explain how overlapping hemifield representations in V1 do not impair vision, we tested the hypothesis that visual projections from nasal and temporal retina create interdigitated left and right visual hemifield representations in V1, similar to the ocular dominance columns observed in neurotypical subjects (Victor et al., 2000). We used high-resolution fMRI at 7T to measure the spatial distribution of responses to left- and right-hemifield stimulation in one achiasmic subject. T 2 -weighted 2D Spin Echo images were acquired at 0.8mm isotropic resolution. The left eye was occluded. To the right eye, a presentation of flickering checkerboards alternated between the left and right visual fields in a blocked stimulus design. The participant performed a demanding orientation-discrimination task at fixation. A general linear model was used to estimate the preference of voxels in V1 to left- and right-hemifield stimulation. The spatial distribution of voxels with significant preference for each hemifield showed interdigitated clusters which densely packed V1 in the right hemisphere. The spatial distribution of hemifield-preference voxels in the achiasmic subject was stable between two days of testing and comparable in scale to that of human ocular dominance columns. These results are the first in vivo evidence showing that visual hemifield representations interdigitate in achiasmic V1 following a similar developmental course to that of ocular dominance columns in V1 with intact optic chiasm. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Proton computed tomography

    International Nuclear Information System (INIS)

    Hanson, K.M.

    1978-01-01

    The use of protons or other heavy charged particles instead of x rays in computed tomography (CT) is explored. The results of an experimental implementation of proton CT are presented. High quality CT reconstructions are obtained at an average dose reduction factor compared with an EMI 5005 x-ray scanner of 10:1 for a 30-cm-diameter phantom and 3.5:1 for a 20-cm diameter. The spatial resolution is limited by multiple Coulomb scattering to about 3.7 mm FWHM. Further studies are planned in which proton and x-ray images of fresh human specimens will be compared. Design considerations indicate that a clinically useful proton CT scanner is eminently feasible

  17. Emission computed tomography

    International Nuclear Information System (INIS)

    Phelps, M.E.

    1977-01-01

    Although there are many common aspects to x-ray transmission and radionuclide emission (ECT) computerized tomography, there are added difficulties and a number of particular factors which form the basis of ECT. The relationship between the physical factors, system design, methodologic approach and assumptions of ECT is discussed. The instrumentation design and application strategies in ECT at this time are diverse and in a rapid stage of development. The approaches are divided into two major categories of Single Photon Counting (SPC) employing scanner and camera concepts with radionuclides of 99 /sup m/Tc, 201 Tl, 123 I etc., and Annihilation Coincidence Detection (ACD) of positron-emitting radionuclides. Six systems in the former and ten systems in the latter category, with examples of typical studies, illustrate the different approaches

  18. Tomography by positrons emission

    International Nuclear Information System (INIS)

    Mosconi, Sergio L.

    1999-01-01

    The tomography by positrons emission is a technology that allows to measure the concentration of positrons emission in a tri dimensional body through external measurements. Among the isotope emissions have carbon isotopes are ( 11 C), of the oxygen ( 15 O), of the nitrogen ( 13 N) that are three the element that constitute the base of the organic chemistry. Theses have on of the PET's most important advantages, since many biological interesting organic molecules can be tracer with these isotopes for the metabolism studies 'in vivo' through PET, without using organic tracers that modify the metabolism. The mentioned isotopes, also possess the characteristic of having short lifetime, that constitute on of PET's advantages from the dosimetric point of view. Among 11 C, 15 O, and 13 N, other isotopes that can be obtained of a generator as the 68 Ga and 82 Rb

  19. Positron emission computed tomography

    International Nuclear Information System (INIS)

    Grover, M.; Schelbert, H.R.

    1985-01-01

    Regional mycardial blood flow and substrate metabolism can be non-invasively evaluated and quantified with positron emission computed tomography (Positron-CT). Tracers of exogenous glucose utilization and fatty acid metabolism are available and have been extensively tested. Specific tracer kinetic models have been developed or are being tested so that glucose and fatty acid metabolism can be measured quantitatively by Positron-CT. Tracers of amino acid and oxygen metabolism are utilized in Positron-CT studies of the brain and development of such tracers for cardiac studies are in progress. Methods to quantify regional myocardial blood flow are also being developed. Previous studies have demonstrated the ability of Positron-/CT to document myocardial infarction. Experimental and clinical studies have begun to identify metabolic markers of reversibly ischemic myocardium. The potential of Positron-CT to reliably detect potentially salvageable myocardium and, hence, to identify appropriate therapeutic interventions is one of the most exciting applications of the technique

  20. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    A positron emission tomography camera having a plurality of detector planes positioned side-by-side around a patient area to detect radiation. Each plane includes a plurality of photomultiplier tubes and at least two rows of scintillation crystals on each photomultiplier tube extend across to adjacent photomultiplier tubes for detecting radiation from the patient area. Each row of crystals on each photomultiplier tube is offset from the other rows of crystals, and the area of each crystal on each tube in each row is different than the area of the crystals on the tube in other rows for detecting which crystal is actuated and allowing the detector to detect more inter-plane slides. The crystals are offset by an amount equal to the length of the crystal divided by the number of rows. The rows of crystals on opposite sides of the patient may be rotated 90 degrees relative to each other

  1. Gantry for computed tomography

    International Nuclear Information System (INIS)

    Kelman, A.L.; O'Dell, W.R.; Brook, R.F.; Hein, P.W.; Brandt, R.T.

    1981-01-01

    A novel design of gantry for use in computed tomography is described in detail. In the new gantry, curved tracks are mounted to the laterally spaced apart sides of the frame which rotates and carries the detector and X-ray source. This permits the frame to be tilted either side of vertical enabling angular slices of body layers to be viewed and allows simplification of the algorithm which the computer uses for image reconstruction. A failsafe, solenoid brake is described which can lock the shaft against rotation. The gantry also contains a hoist mechanism which aids maintenance of the heavy X-ray tube and/or detector arrays. Explicit engineering details are presented. (U.K.)

  2. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    A positron emission tomography camera having a plurality of detector rings positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom. Each ring contains a plurality of scintillation detectors which are positioned around an inner circumference with a septum ring extending inwardly from the inner circumference along each outer edge of each ring. An additional septum ring is positioned in the middle of each ring of detectors and parallel to the other septa rings, whereby the inward extent of all the septa rings may be reduced by one-half and the number of detectors required in each ring is reduced. The additional septa reduces the costs of the positron camera and improves its performance

  3. Positron emission tomography camera

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    A positron emission tomography camera having a plurality of detector rings positioned side-by-side or offset by one-half of the detector cross section around a patient area to detect radiation therefrom. Each detector ring or offset ring includes a plurality of photomultiplier tubes and a plurality of scintillation crystals are positioned relative to the photomultiplier tubes whereby each tube is responsive to more than one crystal. Each alternate crystal in the ring is offset by one-half or less of the thickness of the crystal such that the staggered crystals are seen by more than one photomultiplier tube. This sharing of crystals and photomultiplier tubes allows identification of the staggered crystal and the use of smaller detectors shared by larger photomultiplier tubes thereby requiring less photomultiplier tubes, creating more scanning slices, providing better data sampling, and reducing the cost of the camera. The offset detector ring geometry reduces the costs of the positron camera and improves its performance

  4. Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Fercher, A.F.; Andersen, Peter E.

    2017-01-01

    Optical coherence tomography (OCT) is a technique that is used to peer inside a body noninvasively. Tissue structure defined by tissue absorption and scattering coefficients, and the speed of blood flow, are derived from the characteristics of light remitted by the body. Singly backscattered light...... detected by partial coherence interferometry (PCI) is used to synthesize the tomographic image coded in false colors. A prerequisite of this technique is a low time-coherent but high space-coherent light source, for example, a superluminescent diode or a supercontinuum source. Alternatively, the imaging...... technique can be realized by using ultrafast wavelength scanning light sources. For tissue imaging, the light source wavelengths are restricted to the red and near-infrared (NIR) region from about 600 to 1300 nm, the so-called therapeutic window, where absorption (μa ≈ 0.01 mm−1) is small enough. Transverse...

  5. Waste Inspection Tomography (WIT)

    International Nuclear Information System (INIS)

    Bernardi, R.T.

    1995-01-01

    Waste Inspection Tomography (WIT) provides mobile semi-trailer mounted nondestructive examination (NDE) and assay (NDA) for nuclear waste drum characterization. WIT uses various computed tomography (CT) methods for both NDE and NDA of nuclear waste drums. Low level waste (LLW), transuranic (TRU), and mixed radioactive waste can be inspected and characterized without opening the drums. With externally transmitted x-ray NDE techniques, WIT has the ability to identify high density waste materials like heavy metals, define drum contents in two- and three-dimensional space, quantify free liquid volumes through density and x-ray attenuation coefficient discrimination, and measure drum wall thickness. With waste emitting gamma-ray NDA techniques, WIT can locate gamma emitting radioactive sources in two- and three-dimensional space, identify gamma emitting isotopic species, identify the external activity levels of emitting gamma-ray sources, correct for waste matrix attenuation, provide internal activity approximations, and provide the data needed for waste classification as LLW or TRU. The mobile feature of WIT allows inspection technologies to be brought to the nuclear waste drum storage site without the need to relocate drums for safe, rapid, and cost-effective characterization of regulated nuclear waste. The combination of these WIT characterization modalities provides the inspector with an unprecedented ability to non-invasively characterize the regulated contents of waste drums as large as 110 gallons, weighing up to 1,600 pounds. Any objects that fit within these size and weight restrictions can also be inspected on WIT, such as smaller waste bags and drums that are five and thirty-five gallons

  6. Ocean acoustic tomography

    International Nuclear Information System (INIS)

    Cornuelle, Bruce D; Worcester, Peter F; Dzieciuch, Matthew A

    2008-01-01

    Ocean acoustic tomography (OAT) was proposed in 1979 by Walter Munk and Carl Wunsch as an analogue to x-ray computed axial tomography for the oceans. The oceans are opaque to most electromagnetic radiation, but there is a strong acoustic waveguide, and sound can propagate for 10 Mm and more with distinct multiply-refracted ray paths. Transmitting broadband pulses in the ocean leads to a set of impulsive arrivals at the receiver which characterize the impulse response of the sound channel. The peaks observed at the receiver are assumed to represent the arrival of energy traveling along geometric ray paths. These paths can be distinguished by arrival time, and by arrival angle when a vertical array of receivers is available. Changes in ray arrival time can be used to infer changes in ocean structure. Ray travel time measurements have been a mainstay of long-range acoustic measurements, but the strong sensitivity of ray paths to range-dependent sound speed perturbations makes the ray sampling functions uncertain in real cases. In the ray approximation travel times are sensitive to medium changes only along the corresponding eigenrays. Ray theory is an infinite-frequency approximation, and its eikonal equation has nonlinearities not found in the acoustic wave equation. We build on recent seismology results (kernels for body wave arrivals in the earth) to characterize the kernel for converting sound speed change in the ocean to travel time changes using more complete propagation physics. Wave-theoretic finite frequency kernels may show less sensitivity to small-scale sound speed structure.

  7. Localization of higher grade tumor foci in potential candidates for active surveillance who opt for radical prostatectomy

    Science.gov (United States)

    Hong, Sung Kyu; Eastham, James A.; Fine, Samson W.

    2013-01-01

    Purpose: To investigate actual intraprostatic location of higher graded tumor foci undetected via standard transrectal ultrasound-guided prostate biopsy amongst patients who would be clinically considered appropriate candidates for active surveillance (AS) but underwent radical prostatectomy (RP). Methods: We reviewed entirely-submitted and whole-mounted RP specimens from 169 men who were deemed appropriate for AS clinically, but opted for RP and were found to have higher grade tumors. For each case, tumor nodules were circled and color-coded in a grade-specific manner and digitally scanned to created tumor maps. The locations of tumor foci with Gleason grade ≥4 were stratified by specific sites: anterior, anterolateral, lateral only (not clearly anterior or posterior), posterior, and posterolateral area. Results: Of 169 patients, 86% had clinical stage T1c and 14% T2a. RP Gleason score 7 in all but two men. Higher-grade tumor foci were localized to: anterior (n=66, 39%), anterolateral (n=4, 2%), lateral only (not clearly anterior or posterior) (n=5, 3%), posterior (n=52, 31%), and posterolateral (n=42, 25%) prostate, respectively. Conclusions: Among patients deemed clinically appropriate for AS, higher-grade tumor foci missed by standard prostate biopsies were localized to both the anterior and posterior prostate, without predominance of a particular area. These findings lend additional support to performing repeat standard prostate biopsy in potential candidates for AS and should be considered in efforts to optimize current biopsy strategies for the selection of AS patients. PMID:24392439

  8. Opting out of the commercial use of nuclear power in Germany and challenges arising to nuclear supervision

    International Nuclear Information System (INIS)

    Renneberg, W.

    2001-01-01

    The governing majority in Germany has decided to opt out of the commercial use of nuclear power and to terminate this use in a safe and managed way. In the opinion of the federal government, the reasons for this decision include the potential for severe accidents, which is considered intolerable in the long run even though the probability of occurrence is low. In addition, there are the problems of final storage of radioactive waste, issues associated with the risk of proliferation, and the need to end a deep-seated societal conflict in Germany. In its function as the Top Regulator, the department responsible for nuclear matters of the Federal Ministry for the Environment, Nature Conservation, and Nuclear Safety (BMU) has two important functions: It acts as the federal supervisor of the federal states which execute the Atomic Energy Act on behalf of the federal government, and it exercises the duty of preparing the nuclear policy outlined in the norms established by the federal government. After lengthy discussions with the operators of nuclear power plants an agreement was elaborated in preparation of a solution acceptable to all participants, which essentially defines an electricity quota for nuclear power plant operation and deals with spent fuel and nuclear waste management problems. This implies a number of challenges arising to the BMU as a consequence of the need to further ensure a high safety standard. It also means international efforts as well as the need to counteract the impending loss of competence in the nuclear field. (orig.) [de

  9. Pilot for the Australian Breast Device Registry (ABDR): a national opt-out clinical quality registry for breast device surgery.

    Science.gov (United States)

    Hopper, Ingrid; Best, Renee L; McNeil, John J; Mulvany, Catherine M; Moore, Colin C M; Elder, Elisabeth; Pase, Marie; Cooter, Rodney D; Evans, Sue M

    2017-12-28

    To establish a pilot clinical quality registry (CQR) to monitor the quality of care and device performance for breast device surgery in Australia. All patients having breast device surgery from contributing hospitals in Australia. A literature review was performed which identified quality indicators for breast device surgery. A pilot CQR was established in 2011 to capture prospective data on breast device surgery. An interim Steering Committee and Management Committee were established to provide clinical governance, and guide quality indicator selection. The registry's minimum dataset was formulated in consultation with stakeholder groups; potential quality indicators were assessed in terms of (1) importance and relevance, (2) usability, (3) feasibility to collect and (4) scientific validity. Data collection was by a two-sided paper-based form with manual data entry. Seven sites were recruited, including one public hospital, four private hospitals and two day surgeries. Patients were recruited and opt-out consent used. The pilot breast device registry provides high-quality population-based data. It provides a model for developing a national CQR for breast devices; its minimum dataset and quality indicators reflect the opinions of the broad range of stakeholders. It is easily scalable, and has formed the basis for other international surgical groups establishing similar registries. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. Computed Tomography (CT) -- Sinuses

    Medline Plus

    Full Text Available ... quickly. When you enter the CT scanner, special light lines may be seen projected onto your body, ... its ability to image bone, soft tissue and blood vessels all at the same time. Unlike conventional ...

  11. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... quickly. When you enter the CT scanner, special light lines may be seen projected onto your body, ... its ability to image bone, soft tissue and blood vessels all at the same time. Unlike conventional ...

  12. Multi-Detector Computed Tomography Imaging Techniques in Arterial Injuries

    Directory of Open Access Journals (Sweden)

    Cameron Adler

    2018-04-01

    Full Text Available Cross-sectional imaging has become a critical aspect in the evaluation of arterial injuries. In particular, angiography using computed tomography (CT is the imaging of choice. A variety of techniques and options are available when evaluating for arterial injuries. Techniques involve contrast bolus, various phases of contrast enhancement, multiplanar reconstruction, volume rendering, and maximum intensity projection. After the images are rendered, a variety of features may be seen that diagnose the injury. This article provides a general overview of the techniques, important findings, and pitfalls in cross sectional imaging of arterial imaging, particularly in relation to computed tomography. In addition, the future directions of computed tomography, including a few techniques in the process of development, is also discussed.

  13. ODTbrain: a Python library for full-view, dense diffraction tomography.

    Science.gov (United States)

    Müller, Paul; Schürmann, Mirjam; Guck, Jochen

    2015-11-04

    Analyzing the three-dimensional (3D) refractive index distribution of a single cell makes it possible to describe and characterize its inner structure in a marker-free manner. A dense, full-view tomographic data set is a set of images of a cell acquired for multiple rotational positions, densely distributed from 0 to 360 degrees. The reconstruction is commonly realized by projection tomography, which is based on the inversion of the Radon transform. The reconstruction quality of projection tomography is greatly improved when first order scattering, which becomes relevant when the imaging wavelength is comparable to the characteristic object size, is taken into account. This advanced reconstruction technique is called diffraction tomography. While many implementations of projection tomography are available today, there is no publicly available implementation of diffraction tomography so far. We present a Python library that implements the backpropagation algorithm for diffraction tomography in 3D. By establishing benchmarks based on finite-difference time-domain (FDTD) simulations, we showcase the superiority of the backpropagation algorithm over the backprojection algorithm. Furthermore, we discuss how measurment parameters influence the reconstructed refractive index distribution and we also give insights into the applicability of diffraction tomography to biological cells. The present software library contains a robust implementation of the backpropagation algorithm. The algorithm is ideally suited for the application to biological cells. Furthermore, the implementation is a drop-in replacement for the classical backprojection algorithm and is made available to the large user community of the Python programming language.

  14. Schedule evolution during the life-time of the LHC project

    CERN Document Server

    Foraz, K; Gaillard, H; Hauviller, Claude; Weisz, S

    2007-01-01

    The Large Hadron Collider Project was approved by the CERN Council in December 1994. The CERN management opted from the beginning of the project for a very aggressive installation planning based on a just-in-time sequencing of all activities. This paper aims to draw how different factors (technical development, procurement, logistics and organization) have impacted on the schedule evolution through the lifetime of the project. It describes the cause effect analysis of the major rescheduling that occurred during the installation of the LHC and presents some general conclusions potentially applicable in other projects.

  15. Magnetic resonance tomography in syringomyelia

    International Nuclear Information System (INIS)

    Koehler, D.; Treisch, J.; Hertel, G.; Schoerner, W.; Fiegler, W.; Staedtisches Rudolf-Virchow Krankenhaus, Berlin

    1985-01-01

    Thirteen patients with a clinical diagnosis of syringomyelia were examined by nuclear tomography (0.35 T magnet) in the spin-echo mode. In all thirteen patients, the T1 images (Se 400/35) showed a longitudinal cavity with a signal intensity of CSF. The shape and extent of the syrinx could be adequately demonstrated in 12 of the 13 examinations. Downward displacement of the cerebellar tonsils was seen in eight cases. The examination took between half and one hour. Advantages of magnetic resonance tomography (nuclear tomography) include the absence of artifacts, images in the line of the lesion and its non-invasiveness. (orig.) [de

  16. Computed tomography of the pancreas

    International Nuclear Information System (INIS)

    Kolmannskog, F.; Kolbenstvedt, A.; Aakhus, T.; Bergan, A.; Fausa, O.; Elgjo, K.

    1980-01-01

    The findings by computed tomography in 203 cases of suspected pancreatic tumours, pancreatitis or peripancreatic abnormalities were evaluated. The appearances of the normal and the diseased pancreas are described. Computed tomography is highly accurate in detecting pancreatic masses, but can not differentiate neoplastic from inflammatory disease. The only reliable signs of pancreatic carcinoma are a focal mass in the pancreas, together with liver metastasis. When a pancreatic mass is revealed by computed tomography, CT-guided fine-needle aspiration biopsy of the pancreas is recommended. Thus the need for more invasive diagnostic procedures and explorative laparotomy may be avoided in some patients. (Auth.)

  17. How Strong Is Europeanisation, Really? The Danish Defence Administration and the Opt-Out from the European Security and Defence Policy

    DEFF Research Database (Denmark)

    Olsen, Gorm Rye

    2011-01-01

    The article questions how strong Europeanisation is as an explanation of administrative changes in EU member states. Denmark has an opt-out from the European cooperation on defence, and, therefore, its defence administration represents a critical or a less likely case to test the Europeanisation...... thesis. The article shows that in spite of the opt-out, the administrative structures and the policy processes in the Ministry of Foreign Affairs (MFA) have adapted to the common foreign and security policy (CFSP) and the European security and defence policy (ESDP). Surprisingly, the administrative...... structures and the decision-making processes in the Ministry of Defence (MoD) have also adapted to the ESDP. The latter example emphasises the strength of top-down Europeanisation as a possible explanation of domestic administrative changes in member states. It is argued that Europeanisation per se...

  18. Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in Disseminated Cryptococcosis.

    Science.gov (United States)

    Tripathy, Sarthak; Parida, Girish Kumar; Roy, Shambo Guha; Singhal, Abhinav; Mallick, Saumya Ranjan; Tripathi, Madhavi; Shamim, Shamim Ahmed

    2017-01-01

    Disseminated cryptococcosis without pulmonary involvement is a very rare phenomenon. Patterns of organ involvement in cryptococcosis resemble various other infective conditions as well as malignant conditions on fluorodeoxyglucose positron emission tomography-computed tomography. We present a case of a 43-year-old male patient who had disseminated cryptococcosis. The rarity of the case being noninvolvement of lungs and meninges and resembling more like lymphoma due to the diffuse involvement of the lymph nodes on both sides of the diaphragm.

  19. Computed tomography of the cervical spine: comparison of image quality between a standard-dose and a low-dose protocol using filtered back-projection and iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Becce, Fabio [University of Lausanne, Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Universite Catholique Louvain, Department of Radiology, Cliniques Universitaires Saint-Luc, Brussels (Belgium); Ben Salah, Yosr; Berg, Bruno C. vande; Lecouvet, Frederic E.; Omoumi, Patrick [Universite Catholique Louvain, Department of Radiology, Cliniques Universitaires Saint-Luc, Brussels (Belgium); Verdun, Francis R. [University of Lausanne, Institute of Radiation Physics, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Meuli, Reto [University of Lausanne, Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland)

    2013-07-15

    To compare image quality of a standard-dose (SD) and a low-dose (LD) cervical spine CT protocol using filtered back-projection (FBP) and iterative reconstruction (IR). Forty patients investigated by cervical spine CT were prospectively randomised into two groups: SD (120 kVp, 275 mAs) and LD (120 kVp, 150 mAs), both applying automatic tube current modulation. Data were reconstructed using both FBP and sinogram-affirmed IR. Image noise, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were measured. Two radiologists independently and blindly assessed the following anatomical structures at C3-C4 and C6-C7 levels, using a four-point scale: intervertebral disc, content of neural foramina and dural sac, ligaments, soft tissues and vertebrae. They subsequently rated overall image quality using a ten-point scale. For both protocols and at each disc level, IR significantly decreased image noise and increased SNR and CNR, compared with FBP. SNR and CNR were statistically equivalent in LD-IR and SD-FBP protocols. Regardless of the dose and disc level, the qualitative scores with IR compared with FBP, and with LD-IR compared with SD-FBP, were significantly higher or not statistically different for intervertebral discs, neural foramina and ligaments, while significantly lower or not statistically different for soft tissues and vertebrae. The overall image quality scores were significantly higher with IR compared with FBP, and with LD-IR compared with SD-FBP. LD-IR cervical spine CT provides better image quality for intervertebral discs, neural foramina and ligaments, and worse image quality for soft tissues and vertebrae, compared with SD-FBP, while reducing radiation dose by approximately 40 %. (orig.)

  20. Computed tomography of the cervical spine: comparison of image quality between a standard-dose and a low-dose protocol using filtered back-projection and iterative reconstruction

    International Nuclear Information System (INIS)

    Becce, Fabio; Ben Salah, Yosr; Berg, Bruno C. vande; Lecouvet, Frederic E.; Omoumi, Patrick; Verdun, Francis R.; Meuli, Reto

    2013-01-01

    To compare image quality of a standard-dose (SD) and a low-dose (LD) cervical spine CT protocol using filtered back-projection (FBP) and iterative reconstruction (IR). Forty patients investigated by cervical spine CT were prospectively randomised into two groups: SD (120 kVp, 275 mAs) and LD (120 kVp, 150 mAs), both applying automatic tube current modulation. Data were reconstructed using both FBP and sinogram-affirmed IR. Image noise, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were measured. Two radiologists independently and blindly assessed the following anatomical structures at C3-C4 and C6-C7 levels, using a four-point scale: intervertebral disc, content of neural foramina and dural sac, ligaments, soft tissues and vertebrae. They subsequently rated overall image quality using a ten-point scale. For both protocols and at each disc level, IR significantly decreased image noise and increased SNR and CNR, compared with FBP. SNR and CNR were statistically equivalent in LD-IR and SD-FBP protocols. Regardless of the dose and disc level, the qualitative scores with IR compared with FBP, and with LD-IR compared with SD-FBP, were significantly higher or not statistically different for intervertebral discs, neural foramina and ligaments, while significantly lower or not statistically different for soft tissues and vertebrae. The overall image quality scores were significantly higher with IR compared with FBP, and with LD-IR compared with SD-FBP. LD-IR cervical spine CT provides better image quality for intervertebral discs, neural foramina and ligaments, and worse image quality for soft tissues and vertebrae, compared with SD-FBP, while reducing radiation dose by approximately 40 %. (orig.)