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Sample records for efficiency electronic portal

  1. Electronic patient portals: evidence on health outcomes, satisfaction, efficiency, and attitudes: a systematic review.

    Science.gov (United States)

    Goldzweig, Caroline Lubick; Orshansky, Greg; Paige, Neil M; Towfigh, Ali Alexander; Haggstrom, David A; Miake-Lye, Isomi; Beroes, Jessica M; Shekelle, Paul G

    2013-11-19

    Patient portals tied to provider electronic health record (EHR) systems are increasingly popular. To systematically review the literature reporting the effect of patient portals on clinical care. PubMed and Web of Science searches from 1 January 1990 to 24 January 2013. Hypothesis-testing or quantitative studies of patient portals tethered to a provider EHR that addressed patient outcomes, satisfaction, adherence, efficiency, utilization, attitudes, and patient characteristics, as well as qualitative studies of barriers or facilitators, were included. Two reviewers independently extracted data and addressed discrepancies through consensus discussion. From 6508 titles, 14 randomized, controlled trials; 21 observational, hypothesis-testing studies; 5 quantitative, descriptive studies; and 6 qualitative studies were included. Evidence is mixed about the effect of portals on patient outcomes and satisfaction, although they may be more effective when used with case management. The effect of portals on utilization and efficiency is unclear, although patient race and ethnicity, education level or literacy, and degree of comorbid conditions may influence use. Limited data for most outcomes and an absence of reporting on organizational and provider context and implementation processes. Evidence that patient portals improve health outcomes, cost, or utilization is insufficient. Patient attitudes are generally positive, but more widespread use may require efforts to overcome racial, ethnic, and literacy barriers. Portals represent a new technology with benefits that are still unclear. Better understanding requires studies that include details about context, implementation factors, and cost.

  2. ELECTRONIC COMMERCE PORTAL

    OpenAIRE

    Georgeta Soava

    2011-01-01

    Today companies are faced with the need to exploit technology changing computer environments, in order to improve customer satisfaction and reduce costs. A successful approach to electronic portals is an effective demonstration of the new ways of relating to the client. The objectives that we have considered for the realization of e-commerce portal can be summarized as follows: structured communication, effective collaboration, complet and closed circuit of orders and deliveries, inventory op...

  3. A View on Electronic Learning Portals

    OpenAIRE

    Zavaraqi, Rasoul

    2009-01-01

    Portals are less than a decade old. They have come to cover are areas of electronic services, including electronic learning. With their efficient communication and information capabilities, these portals are capable of realizing novel learning concepts such as structuralism, active and cooperative learning. The present paper endeavors to discuss the latest understanding, theories and concepts regarding E-learning portals and to review the issues and steps that should be considered in designin...

  4. Electronic portal imaging devices

    International Nuclear Information System (INIS)

    Lief, Eugene

    2008-01-01

    The topics discussed include, among others, the following: Role of portal imaging; Port films vs. EPID; Image guidance: Elekta volume view; Delivery verification; Automation tasks of portal imaging; Types of portal imaging (Fluorescent screen, mirror, and CCD camera-based imaging; Liquid ion chamber imaging; Amorpho-silicon portal imagers; Fluoroscopic portal imaging; Kodak CR reader; and Other types of portal imaging devices); QA of EPID; and Portal dosimetry (P.A.)

  5. Quality assurance for electronic portal imaging devices

    International Nuclear Information System (INIS)

    Shalev, S.; Rajapakshe, R.; Gluhchev, G.; Luchka, K.

    1997-01-01

    Electronic portal imaging devices (EPIDS) are assuming an ever-increasing role in the verification of radiation treatment accuracy. They are used both in a passive capacity, for the determination of field displacement distributions (''setup errors''), and also in an active role whereby the patient setup is corrected on the basis of electronic portal images. In spite of their potential impact on the precision of patient treatment, there are few quality assurance procedures available, and most of the EPIDS in clinical use are subject, at best, to only perfunctory quality assurance. The goals of this work are (a) to develop an objective and reproducible test for EPID image quality on the factory floor and during installation of the EPID on site; (b) to provide the user with a simple and accurate tool for acceptance, commissioning, and routine quality control; and (c) to initiate regional, national and international collaboration in the implementation of standardized, objective, and automated quality assurance procedures. To this end we have developed an automated test in which a simple test object is imaged daily, and the spatial and contrast resolution of the EPID are automatically evaluated in terms of ''acceptable'', ''warning'' and ''stop'' criteria. Our experience over two years shows the test to be highly sensitive, reproducible, and inexpensive in time and effort. Inter-institutional trials are under way in Canada, US and Europe which indicate large variations in EPID image quality from one EPID to another, and from one center to another. We expect the new standardized quality assurance procedure to lead to improved, and consistent image quality, increased operator acceptance of the technology, and agreement on uniform standards by equipment suppliers and health care agencies. (author)

  6. Patient activation and use of an electronic patient portal.

    Science.gov (United States)

    Ancker, Jessica S; Osorio, Snezana N; Cheriff, Adam; Cole, Curtis L; Silver, Michael; Kaushal, Rainu

    2015-01-01

    Electronic patient portals give patients access to personal medical data, potentially creating opportunities to improve knowledge, self-efficacy, and engagement in healthcare. The combination of knowledge, self-efficacy, and engagement has been termed activation. Our objective was to assess the relationship between patient activation and outpatient use of a patient portal. Survey. A telephone survey was conducted with 180 patients who had been given access to a portal, 113 of whom used it and 67 of whom did not. The validated patient activation measure (PAM) was administered along with questions about demographics and behaviors. Portal users were no different from nonusers in patient activation. Portal users did have higher education level and more frequent Internet use, and were more likely to have precisely 2 prescription medications than to have more or fewer. Patients who chose to use an electronic patient portal were not more highly activated than nonusers, although they were more educated and more likely to be Internet users.

  7. MO-FG-202-04: Gantry-Resolved Linac QA for VMAT: A Comprehensive and Efficient System Using An Electronic Portal Imaging Device

    Energy Technology Data Exchange (ETDEWEB)

    Zwan, B J [Central Coast Cancer Centre, Gosford, NSW (Australia); University of Newcastle, Newcastle, NSW (Australia); Barnes, M; Greer, P B [University of Newcastle, Newcastle, NSW (Australia); Calvary Mater Hospital, Newcastle, NSW (Australia); Hindmarsh, J; Seymour, E [Central Coast Cancer Centre, Gosford, NSW (Australia); O’Connor, D J [University of Newcastle, Newcastle, NSW (Australia); Keall, P J [University of Sydney, Camperdown, NSW (Australia)

    2016-06-15

    Purpose: To automate gantry-resolved linear accelerator (linac) quality assurance (QA) for volumetric modulated arc therapy (VMAT) using an electronic portal imaging device (EPID). Methods: A QA system for VMAT was developed that uses an EPID, frame-grabber assembly and in-house developed image processing software. The system relies solely on the analysis of EPID image frames acquired without the presence of a phantom. Images were acquired at 8.41 frames per second using a frame grabber and ancillary acquisition computer. Each image frame was tagged with a gantry angle from the linac’s on-board gantry angle encoder. Arc-dynamic QA plans were designed to assess the performance of each individual linac component during VMAT. By analysing each image frame acquired during the QA deliveries the following eight machine performance characteristics were measured as a function of gantry angle: MLC positional accuracy, MLC speed constancy, MLC acceleration constancy, MLC-gantry synchronisation, beam profile constancy, dose rate constancy, gantry speed constancy, dose-gantry angle synchronisation and mechanical sag. All tests were performed on a Varian iX linear accelerator equipped with a 120 leaf Millennium MLC and an aS1000 EPID (Varian Medical Systems, Palo Alto, CA, USA). Results: Machine performance parameters were measured as a function of gantry angle using EPID imaging and compared to machine log files and the treatment plan. Data acquisition is currently underway at 3 centres, incorporating 7 treatment units, at 2 weekly measurement intervals. Conclusion: The proposed system can be applied for streamlined linac QA and commissioning for VMAT. The set of test plans developed can be used to assess the performance of each individual components of the treatment machine during VMAT deliveries as a function of gantry angle. The methodology does not require the setup of any additional phantom or measurement equipment and the analysis is fully automated to allow for

  8. MO-FG-202-04: Gantry-Resolved Linac QA for VMAT: A Comprehensive and Efficient System Using An Electronic Portal Imaging Device

    International Nuclear Information System (INIS)

    Zwan, B J; Barnes, M; Greer, P B; Hindmarsh, J; Seymour, E; O’Connor, D J; Keall, P J

    2016-01-01

    Purpose: To automate gantry-resolved linear accelerator (linac) quality assurance (QA) for volumetric modulated arc therapy (VMAT) using an electronic portal imaging device (EPID). Methods: A QA system for VMAT was developed that uses an EPID, frame-grabber assembly and in-house developed image processing software. The system relies solely on the analysis of EPID image frames acquired without the presence of a phantom. Images were acquired at 8.41 frames per second using a frame grabber and ancillary acquisition computer. Each image frame was tagged with a gantry angle from the linac’s on-board gantry angle encoder. Arc-dynamic QA plans were designed to assess the performance of each individual linac component during VMAT. By analysing each image frame acquired during the QA deliveries the following eight machine performance characteristics were measured as a function of gantry angle: MLC positional accuracy, MLC speed constancy, MLC acceleration constancy, MLC-gantry synchronisation, beam profile constancy, dose rate constancy, gantry speed constancy, dose-gantry angle synchronisation and mechanical sag. All tests were performed on a Varian iX linear accelerator equipped with a 120 leaf Millennium MLC and an aS1000 EPID (Varian Medical Systems, Palo Alto, CA, USA). Results: Machine performance parameters were measured as a function of gantry angle using EPID imaging and compared to machine log files and the treatment plan. Data acquisition is currently underway at 3 centres, incorporating 7 treatment units, at 2 weekly measurement intervals. Conclusion: The proposed system can be applied for streamlined linac QA and commissioning for VMAT. The set of test plans developed can be used to assess the performance of each individual components of the treatment machine during VMAT deliveries as a function of gantry angle. The methodology does not require the setup of any additional phantom or measurement equipment and the analysis is fully automated to allow for

  9. A Standardization Framework for Electronic Government Service Portals

    Science.gov (United States)

    Sarantis, Demetrios; Tsiakaliaris, Christos; Lampathaki, Fenareti; Charalabidis, Yannis

    Although most eGovernment interoperability frameworks (eGIFs) cover adequately the technical aspects of developing and supporting the provision of electronic services to citizens and businesses, they do not exclusively address several important areas regarding the organization, presentation, accessibility and security of the content and the electronic services offered through government portals. This chapter extends the scope of existing eGIFs presenting the overall architecture and the basic concepts of the Greek standardization framework for electronic government service portals which, for the first time in Europe, is part of a country's eGovernment framework. The proposed standardization framework includes standards, guidelines and recommendations regarding the design, development and operation of government portals that support the provision of administrative information and services to citizens and businesses. By applying the guidelines of the framework, the design, development and operation of portals in central, regional and municipal government can be systematically addressed resulting in an applicable, sustainable and ever-expanding framework.

  10. On the Efficiency of Spam Mailing and Portal Advertising

    OpenAIRE

    Martin Bandulet

    2005-01-01

    The objective of this paper is to provide a simple approach endogenizing the welfare reducing or welfare enhancing effect of informative advertising. Using this approach, it is possible to analyse the welfare consequences of a technology shock that reduces unit information costs, and to explain whether electronic junk mails or portal advertising will cause welfare gains or losses in a competitive environment.

  11. Algorithms for contrast enhancement of electronic portal images

    International Nuclear Information System (INIS)

    Díez, S.; Sánchez, S.

    2015-01-01

    An implementation of two new automatized image processing algorithms for contrast enhancement of portal images is presented as suitable tools which facilitate the setup verification and visualization of patients during radiotherapy treatments. In the first algorithm, called Automatic Segmentation and Histogram Stretching (ASHS), the portal image is automatically segmented in two sub-images delimited by the conformed treatment beam: one image consisting of the imaged patient obtained directly from the radiation treatment field, and the second one is composed of the imaged patient outside it. By segmenting the original image, a histogram stretching can be independently performed and improved in both regions. The second algorithm involves a two-step process. In the first step, a Normalization to Local Mean (NLM), an inverse restoration filter is applied by dividing pixel by pixel a portal image by its blurred version. In the second step, named Lineally Combined Local Histogram Equalization (LCLHE), the contrast of the original image is strongly improved by a Local Contrast Enhancement (LCE) algorithm, revealing the anatomical structures of patients. The output image is lineally combined with a portal image of the patient. Finally the output images of the previous algorithms (NLM and LCLHE) are lineally combined, once again, in order to obtain a contrast enhanced image. These two algorithms have been tested on several portal images with great results. - Highlights: • Two Algorithms are implemented to improve the contrast of Electronic Portal Images. • The multi-leaf and conformed beam are automatically segmented into Portal Images. • Hidden anatomical and bony structures in portal images are revealed. • The task related to the patient setup verification is facilitated by the contrast enhancement then achieved.

  12. A literature review of electronic portal imaging for radiotherapy dosimetry

    NARCIS (Netherlands)

    van Elmpt, Wouter; McDermott, Leah; Nijsten, Sebastiaan; Wendling, Markus; Lambin, Philippe; Mijnheer, Ben

    2008-01-01

    Electronic portal imaging devices (EPIDs) have been the preferred tools for verification of patient positioning for radiotherapy in recent decades. Since EPID images contain dose information, many groups have investigated their use for radiotherapy dose measurement. With the introduction of the

  13. INTEGRATION AND SYSTEM FAILURES OF ELECTRONIC GOVERNMENTAL PROCUREMENT SYSTEMS IN TURKEY AND PROPOSALS FOR MORE EFFICIENT SYSTEMS IN THE LIGHT OF B2B PORTAL MOVEMENTS

    OpenAIRE

    Yildirim, Fazli; Telli Yamamoto, Gonca

    2011-01-01

    Today’s business dynamics are rapidly changing, especially for the private sector in the world and new paradigm which is called as the electronic environment is starting to dominate the business life. Most of the companies trying to adapt these changes with their company structure and most of them were re-engineered their business models with this new wave. In Turkey, government is trying to transform their services in to digital world for gaining more speed, decreasing the costs and satisfyi...

  14. Prospective clinical evaluation of an electronic portal imaging device

    International Nuclear Information System (INIS)

    Michalski, Jeff M.; Graham, Mary V.; Bosch, Walter R.; Wong, John; Gerber, Russell L.; Cheng, Abel; Tinger, Alfred; Valicenti, Richard K.

    1996-01-01

    Purpose: To determine whether the clinical implementation of an electronic portal imaging device can improve the precision of daily external beam radiotherapy. Methods and Materials: In 1991, an electronic portal imaging device was installed on a dual energy linear accelerator in our clinic. After training the radiotherapy technologists in the acquisition and evaluation of portal images, we performed a randomized study to determine whether online observation, interruption, and intervention would result in more precise daily setup. The patients were randomized to one of two groups: those whose treatments were actively monitored by the radiotherapy technologists and those that were imaged but not monitored. The treating technologists were instructed to correct the following treatment errors: (a) field placement error (FPE) > 1 cm; (b) incorrect block; (c) incorrect collimator setting; (d) absent customized block. Time of treatment delivery was recorded by our patient tracking and billing computers and compared to a matched set of patients not participating in the study. After the patients radiation therapy course was completed, an offline analysis of the patient setup error was planned. Results: Thirty-two patients were treated to 34 anatomical sites in this study. In 893 treatment sessions, 1,873 fields were treated (1,089 fields monitored and 794 fields unmonitored). Ninety percent of the treated fields had at least one image stored for offline analysis. Eighty-seven percent of these images were analyzed offline. Of the 1,011 fields imaged in the monitored arm, only 14 (1.4%) had an intervention recorded by the technologist. Despite infrequent online intervention, offline analysis demonstrated that the incidence of FPE > 10 mm in the monitored and unmonitored groups was 56 out of 881 (6.1%) and 95 out of 595 (11.2%), respectively; p 10 mm was confined to the pelvic fields. The time to treat patients in this study was 10.78 min (monitored) and 10.10 min (unmonitored

  15. A radiation-tolerant electronic readout system for portal imaging

    Science.gov (United States)

    Östling, J.; Brahme, A.; Danielsson, M.; Iacobaeus, C.; Peskov, V.

    2004-06-01

    A new electronic portal imaging device, EPID, is under development at the Karolinska Institutet and the Royal Institute of Technology. Due to considerable demands on radiation tolerance in the radiotherapy environment, a dedicated electronic readout system has been designed. The most interesting aspect of the readout system is that it allows to read out ˜1000 pixels in parallel, with all electronics placed outside the radiation beam—making the detector more radiation resistant. In this work we are presenting the function of a small prototype (6×100 pixels) of the electronic readout board that has been tested. Tests were made with continuous X-rays (10-60 keV) and with α particles. The results show that, without using an optimised gas mixture and with an early prototype only, the electronic readout system still works very well.

  16. Characterization of a high-elbow, fluoroscopic electronic portal imaging device for portal dosimetry

    International Nuclear Information System (INIS)

    Boer, J.C.J. de; Visser, A.G.

    2000-01-01

    The application of a newly developed fluoroscopic (CCD-camera based) electronic portal imaging device (EPID) in portal dosimetry is investigated. A description of the EPID response to dose is presented in terms of stability, linearity and optical cross-talk inside the mechanical structure. The EPID has a relatively large distance (41 cm on-axis) between the fluorescent screen and the mirror (high-elbow), which results in cross-talk with properties quite different from that of the low-elbow fluoroscopic EPIDs that have been studied in the literature. In contrast with low-elbow systems, the maximum cross-talk is observed for points of the fluorescent screen that have the largest distance to the mirror, which is explained from the geometry of the system. An algorithm to convert the images of the EPID into portal dose images (PDIs) is presented. The correction applied for cross-talk is a position-dependent additive operation on the EPID image pixel values, with a magnitude that depends on a calculated effective field width. Deconvolution with a point spread function, as applied for low-elbow systems, is not required. For a 25 MV beam, EPID PDIs and ionization chamber measurements in the EPID detector plane were obtained behind an anthropomorphic phantom and a homogeneous absorber for various field shapes. The difference in absolute dose between the EPID and ionization chamber measurements, averaged over the four test fields presented in this paper, was 0.1±0.5% (1 SD) over the entire irradiation field, with no deviation larger than 2%. (author)

  17. Front-end electronics for the Muon Portal project

    Energy Technology Data Exchange (ETDEWEB)

    Garozzo, S.; Marano, D.; Bonanno, G.; Grillo, A.; Romeo, G.; Timpanaro, M.C. [INAF, Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Lo Presti, D.; Riggi, F.; Russo, V.; Bonanno, D.; La Rocca, P.; Longhitano, F.; Bongiovanni, D.G. [Università di Catania, Dipartimento di Fisica e Astronomia, and INFN, Sezione di Catania, Via S. Sofia 64, I-95123 Catania (Italy); Fallica, G.; Valvo, G. [ST-Microelectronics, Stradale V Primosole 50, Catania (Italy)

    2016-10-11

    The Muon Portal Project was born as a joint initiative between Italian research and industrial partners, aimed at the construction of a real-size working detector prototype to inspect the content of traveling containers by means of secondary cosmic-ray muon radiation and recognize potentially dangerous hidden materials. The tomographic image is obtained by reconstructing the incoming and outgoing muon trajectories when crossing the inspected volume, employing two tracker planes located above and below the container under inspection. In this paper, the design and development of the front-end electronics of the Muon Portal detector is presented, with particular emphasis being devoted to the photo-sensor devices detecting the scintillation light and to the read-out circuitry which is in charge of processing and digitizing the analog pulse signals. In addition, the remote control system, mechanical housing, and thermal cooling system of all structural blocks of the Muon Portal tracker are also discussed, demonstrating the effectiveness and functionality of the adopted design.

  18. Electronic Health Record Portal Adoption: a cross country analysis.

    Science.gov (United States)

    Tavares, Jorge; Oliveira, Tiago

    2017-07-05

    This study's goal is to understand the factors that drive individuals to adopt Electronic Health Record (EHR) portals and to estimate if there are differences between countries with different healthcare models. We applied a new adoption model using as a starting point the extended Unified Theory of Acceptance and Use of Technology (UTAUT2) by incorporating the Concern for Information Privacy (CFIP) framework. To evaluate the research model we used the partial least squares (PLS) - structural equation modelling (SEM) approach. An online questionnaire was administrated in the United States (US) and Europe (Portugal). We collected 597 valid responses. The statistically significant factors of behavioural intention are performance expectancy ([Formula: see text] total  = 0.285; P expectancy ([Formula: see text] total  = 0.160; P value ([Formula: see text] total  = 0.152; P value are only predictors in the US group. The model explained 53% of the variance in behavioural intention and 36% of the variance in use behaviour. Our study identified critical factors for the adoption of EHR portals and significant differences between the countries. Confidentiality issues do not seem to influence acceptance. The EHR portals usage patterns are significantly higher in US compared to Portugal.

  19. Importance of daily electronic portal imaging in radiotherapy

    International Nuclear Information System (INIS)

    Bell, L. J.; Shakespeare, T. P.; Willis, A.

    2008-01-01

    Full text: An audit was conducted on 20 randomly selected patients who had daily electronic portal imaging during the course of their radiotherapy treatment. The daily images were reviewed to determine whether they were within tolerance according to departmental protocol. If they were not, the actions that were taken were documented. Four treatment areas (spine, chest, breast and prostate) were compared among five patients belonging to each of these categories. The patients were also categorized according to their treatment intent (radical or palliative). A total of 889 electronic portal images of 475 fractions were audited and 33.5% of all fractions were outside tolerance. It was found that 95% of patients needed an action during their treatment and 80% of the patients needed a treatment centre move during the course of their treatment. We found that errors occurred throughout the treatment and it was not possible to predict patients who could have daily imaging omitted. Concordance between radiation therapists and radiation oncologists for identification of error was also investigated. Despite the use of familiar electronic portal imaging protocols, image reviewers (radiation therapists and radiation oncologists) disagreed in interpretation 10% of the time. Our results support the hypothesis that daily imaging may be a useful tool for patients undergoing radiotherapy and that imaging may be ideally carried out before each fraction. Image assessments would be ideally carried out by a team approach, with all images reviewed by both radiation therapists and radiation oncologists. This approach has significant resource implications and may require review of current Medicare and Health Program Grant reimbursements.

  20. Development of Geometrical Quality Control Real-time Analysis Program using an Electronic Portal Imaging

    International Nuclear Information System (INIS)

    Lee, Sang Rok; Jung, Kyung Yong; Jang, Min Sun; Lee, Byung Gu; Kwon, Young Ho

    2012-01-01

    To develop a geometrical quality control real-time analysis program using an electronic portal imaging to replace film evaluation method. A geometrical quality control item was established with the Eclipse treatment planning system (Version 8.1, Varian, USA) after the Electronic Portal Imaging Device (EPID) took care of the problems occurring from the fixed substructure of the linear accelerator (CL-iX, Varian, USA). Electronic portal image (single exposure before plan) was created at the treatment room's 4DTC (Version 10.2, Varian, USA) and a beam was irradiated in accordance with each item. The gaining the entire electronic portal imaging at the Off-line review and was evaluated by a self-developed geometrical quality control real-time analysis program. As for evaluation methods, the intra-fraction error was analyzed by executing 5 times in a row under identical conditions and procedures on the same day, and in order to confirm the infer-fraction error, it was executed for 10 days under identical conditions of all procedures and was compared with the film evaluation method using an Iso-align quality control device. Measurement and analysis time was measured by sorting the time into from the device setup to data achievement and the time amount after the time until the completion of analysis and the convenience of the users and execution processes were compared. The intra-fraction error values for each average 0.1, 0.2, 0.3, 0.2 mm at light-radiation field coincidence, collimator rotation axis, couch rotation axis and gantry rotation axis. By checking the infer-fraction error through 10 days of continuous quality control, the error values obtained were average 1.7, 1.4, 0.7, 1.1 mm for each item. Also, the measurement times were average 36 minutes, 15 minutes for the film evaluation method and electronic portal imaging system, and the analysis times were average 30 minutes, 22 minutes. When conducting a geometrical quality control using an electronic portal imaging

  1. Analysis and modeling of electronic portal imaging exit dose measurements

    International Nuclear Information System (INIS)

    Pistorius, S.; Yeboah, C.

    1995-01-01

    In spite of the technical advances in treatment planning and delivery in recent years, it is still unclear whether the recommended accuracy in dose delivery is being achieved. Electronic portal imaging devices, now in routine use in many centres, have the potential for quantitative dosimetry. As part of a project which aims to develop an expert-system based On-line Dosimetric Verification (ODV) system we have investigated and modelled the dose deposited in the detector of a video based portal imaging system. Monte Carlo techniques were used to simulate gamma and x-ray beams in homogeneous slab phantom geometries. Exit doses and energy spectra were scored as a function of (i) slab thickness, (ii) field size and (iii) the air gap between the exit surface and the detector. The results confirm that in order to accurately calculate the dose in the high atomic number Gd 2 O 2 S detector for a range of air gaps, field sizes and slab thicknesses both the magnitude of the primary and scattered components and their effective energy need to be considered. An analytic, convolution based model which attempts to do this is proposed. The results of the simulation and the ability of the model to represent these data will be presented and discussed. This model is used to show that, after training, a back-propagation feed-forward cascade correlation neural network has the ability to identify and recognise the cause of, significant dosimetric errors

  2. Analysis of patient setup accuracy using electronic portal imaging device

    International Nuclear Information System (INIS)

    Onogi, Yuzo; Aoki, Yukimasa; Nakagawa, Keiichi

    1996-01-01

    Radiation therapy is performed in many fractions, and accurate patient setup is very important. This is more significant nowadays because treatment planning and radiation therapy are more precisely performed. Electronic portal imaging devices and automatic image comparison algorithms let us analyze setup deviations quantitatively. With such in mind we developed a simple image comparison algorithm. Using 2459 electronic verification images (335 ports, 123 treatment sites) generated during the past three years at our institute, we evaluated the results of the algorithm, and analyzed setup deviations according to the area irradiated, use of a fixing device (shell), and arm position. Calculated setup deviation was verified visually and their fitness was classified into good, fair, bad, and incomplete. The result was 40%, 14%, 22%, 24% respectively. Using calculated deviations classified as good (994 images), we analyzed setup deviations. Overall setup deviations described in 1 SD along axes x, y, z, was 1.9 mm, 2.5 mm, 1.7 mm respectively. We classified these deviations into systematic and random components, and found that random error was predominant in our institute. The setup deviations along axis y (cranio-caudal direction) showed larger distribution when treatment was performed with the shell. Deviations along y (cranio-caudal) and z (anterior-posterior) had larger distribution when treatment occurred with the patient's arm elevated. There was a significant time-trend error, whose deviations become greater with time. Within all evaluated ports, 30% showed a time-trend error. Using an electronic portal imaging device and automatic image comparison algorithm, we are able to analyze setup deviations more precisely and improve setup method based on objective criteria. (author)

  3. Development and application of efficient portal imaging solutions

    International Nuclear Information System (INIS)

    Boer, J.C.J. de

    2003-01-01

    This thesis describes the theoretical derivation and clinical application of methods to measure and improve patient setup in radiotherapy by means of electronic portal imaging devices (EPIDs). The focus is on methods that (1) are simple to implement and (2) add minimal workload. First, the relation between setup errors and treatment planning margins is quantified in a population-statistics approach. A major result is that systematic errors (recurring each treatment fraction) require about three times larger margins than random errors (fluctuating from fraction to fraction). Therefore, the emphasis is on reduction of systematic setup errors using off-line correction protocols. The new no action level (NAL) protocol, aimed at significant reduction of systematic errors using a small number of imaged fractions, is proposed and investigated in detail. It is demonstrated that the NAL protocol provides final distributions of residue systematic errors at least as good as the most widely applied comparable protocol, the shrinking action level (SAL) protocol, but uses only 3 imaged fractions per patient instead of the 8-10 required by SAL. The efficacy of NAL is demonstrated retrospectively on a database of measured setup errors involving 600 patients with weekly set-up measurements and prospectively in a group of 30 patients. The general properties of NAL are investigated using both analytical and Monte Carlo calculations. As an add-on to NAL, a correction verification (COVER) protocol has been developed using computer simulations combined with a risk analysis. With COVER, a single additional imaged fraction per patient is sufficient to reduce the detrimental effect of possible systematic mistakes in the execution of setup corrections to negligible levels. The high accuracy achieved with off-line setup corrections (yielding SDs of systematic errors ∼1 mm) is demonstrated in clinical studies involving 60 lung cancer patients and 31 head-and-neck patients. Furthermore

  4. Theoretical analysis and experimental evaluation of a CsI(Tl) based electronic portal imaging system

    International Nuclear Information System (INIS)

    Sawant, Amit; Zeman, Herbert; Samant, Sanjiv; Lovhoiden, Gunnar; Weinberg, Brent; DiBianca, Frank

    2002-01-01

    This article discusses the design and analysis of a portal imaging system based on a thick transparent scintillator. A theoretical analysis using Monte Carlo simulation was performed to calculate the x-ray quantum detection efficiency (QDE), signal to noise ratio (SNR) and the zero frequency detective quantum efficiency [DQE(0)] of the system. A prototype electronic portal imaging device (EPID) was built, using a 12.7 mm thick, 20.32 cm diameter, CsI(Tl) scintillator, coupled to a liquid nitrogen cooled CCD TV camera. The system geometry of the prototype EPID was optimized to achieve high spatial resolution. The experimental evaluation of the prototype EPID involved the determination of contrast resolution, depth of focus, light scatter and mirror glare. Images of humanoid and contrast detail phantoms were acquired using the prototype EPID and were compared with those obtained using conventional and high contrast portal film and a commercial EPID. A theoretical analysis was also carried out for a proposed full field of view system using a large area, thinned CCD camera and a 12.7 mm thick CsI(Tl) crystal. Results indicate that this proposed design could achieve DQE(0) levels up to 11%, due to its order of magnitude higher QDE compared to phosphor screen-metal plate based EPID designs, as well as significantly higher light collection compared to conventional TV camera based systems

  5. Increase in Efficiency of Use of Pedestrian Radiation Portal Monitors

    Science.gov (United States)

    Solovev, D. B.; Merkusheva, A. E.

    2017-11-01

    Most international airports in the world use radiation portal monitors (RPM) for primary radiation control organization. During the exploitation pedestrian radiation portal monitors operators (in the Russian Federation it is a special subdivision of customs officials) have certain problems related to the search of an ionizing radiation source causing the alarm signal of a radiation monitor. Radiation portal monitors at standard (factory) settings have to find out the illegal moving of the radioisotopes moved by physical persons passing through a controlled zone and having a steady radiation by the gamma or neutron channel. The problem is that recently the number of the ownerships who underwent treatment or medical diagnostics with the use of radio pharmaceuticals considerably increased, i.e,. ownerships represent such an ionizing radiation source. The operator of the radiation portal monitor has to define very quickly whether the ownership is a violator (takes unsolved radioisotopes illegally) or is just a patient of the clinic who underwent treatment/diagnostics with the use of radio pharmaceuticals. The research showing the radioisotopes which are most often used in the medical purposes are given in article, it is offered to use the new software developed by the authors allowing the operator of the radiation portal monitor to define the location of the ownership which has such ionizing radiation source by the activity of radiation similar to the radiation from radio pharmaceuticals.

  6. Verification of setup errors in external beam radiation therapy using electronic portal imaging

    International Nuclear Information System (INIS)

    Krishna Murthy, K.; Al-Rahbi, Zakiya; Sivakumar, S.S.; Davis, C.A.; Ravichandran, R.

    2008-01-01

    The objective of this study was to conduct an audit on QA aspects of treatment delivery by the verification of the treatment fields position on different days to document the efficiency of immobilization methods and reproducibility of treatment. A retrospective study was carried out on 60 patients, each 20 treated for head and neck, breast, and pelvic sites; and a total of 506 images obtained by electronic portal imaging device (EPID) were analyzed. The portal images acquired using the EPID systems attached to the Varian linear accelerators were superimposed on the reference images. The anatomy matching software (Varian portal Vision. 6.0) was used, and the displacements in two dimensions and rotation were noted for each treated field to study the patient setup errors. The percentages of mean deviations more than 3 mm in lateral (X) and longitudinal (Y) directions were 17.5%, 11.25%, and 7.5% for breast, pelvis, and head and neck cases respectively. In all cases, the percentage of mean deviation with more than 5 mm error was 0.83%. The maximum average mean deviation in all the cases was 1.87. The average mean SD along X and Y directions in all the cases was less than 2.65. The results revealed that the ranges of setup errors are site specific and immobilization methods improve reproducibility. The observed variations were well within the limits. The study confirmed the accuracy and quality of treatments delivered to the patients. (author)

  7. Personal health records as portal to the electronic medical record.

    Science.gov (United States)

    Cahill, Jennifer E; Gilbert, Mark R; Armstrong, Terri S

    2014-03-01

    This topic review discusses the evolving clinical challenges associated with the implementation of electronic personal health records (PHR) that are fully integrated with electronic medical records (EMR). The benefits of facilitating patient access to the EMR through web-based, PHR-portals may be substantial; foremost is the potential to enhance the flow of information between patient and healthcare practitioner. The benefits of improved communication and transparency of care are presumed to be a reduction in clinical errors, increased quality of care, better patient-management of disease, and better disease and symptom comprehension. Yet PHR databases allow patients open access to newly-acquired clinical data without the benefit of concurrent expert clinical interpretation, and therefore may create the potential for greater patient distress and uncertainty. With specific attention to neuro-oncology patients, this review focuses on the developing conflicts and consequences associated with the use of a PHR that parallels data acquisition of the EMR in real-time. We conclude with a discussion of recommendations for implementing fully-integrated PHR for neuro-oncology patients.

  8. Rapid portal imaging with a high-efficiency, large field-of-view detector.

    Science.gov (United States)

    Mosleh-Shirazi, M A; Evans, P M; Swindell, W; Symonds-Tayler, J R; Webb, S; Partridge, M

    1998-12-01

    The design, construction, and performance evaluation of an electronic portal imaging device (EPID) are described. The EPID has the same imaging geometry as the current mirror-based systems except for the x-ray detection stage, where a two-dimensional (2D) array of 1 cm thick CsI(Tl) detector elements are utilized. The approximately 18% x-ray quantum efficiency of the scintillation detector and its 30 x 40 cm2 field-of-view at the isocenter are greater than other area-imaging EPIDs. The imaging issues addressed are theoretical and measured signal-to-noise ratio, linearity of the imaging chain, influence of frame-summing on image quality and image calibration. Portal images of test objects and a humanoid phantom are used to measure the performance of the system. An image quality similar to the current devices is achieved but with a lower dose. With approximately 1 cGy dose delivered by a 6 MV beam, a 2 mm diam structure of 1.3% contrast and an 18 mm diam object of 0.125% contrast can be resolved without using image-enhancement methods. A spatial resolution of about 2 mm at the isocenter is demonstrated. The capability of the system to perform fast sequential imaging, synchronized with the radiation pulses, makes it suitable for patient motion studies and verification of intensity-modulated beams as well as its application in cone-beam megavoltage computed tomography.

  9. Investigation of tilted dose kernels for portal dose prediction in a-Si electronic portal imagers

    International Nuclear Information System (INIS)

    Chytyk, K.; McCurdy, B. M. C.

    2006-01-01

    The effect of beam divergence on dose calculation via Monte Carlo generated dose kernels was investigated in an amorphous silicon electronic portal imaging device (EPID). The flat-panel detector was simulated in EGSnrc with an additional 3.0 cm water buildup. The model included details of the detector's imaging cassette and the front cover upstream of it. To approximate the effect of the EPID's rear housing, a 2.1 cm air gap and 1.0 cm water slab were introduced into the simulation as equivalent backscatter material. Dose kernels were generated with an incident pencil beam of monoenergetic photons of energy 0.1, 2, 6, and 18 MeV. The orientation of the incident pencil beam was varied from 0 deg. to 14 deg. in 2 deg. increments. Dose was scored in the phosphor layer of the detector in both cylindrical (at 0 deg. ) and Cartesian (at 0 deg. -14 deg.) geometries. To reduce statistical fluctuations in the Cartesian geometry simulations at large radial distances from the incident pencil beam, the voxels were first averaged bilaterally about the pencil beam and then combined into concentric square rings of voxels. Profiles of the EPID dose kernels displayed increasing asymmetry with increasing angle and energy. A comparison of the superposition (tilted kernels) and convolution (parallel kernels) dose calculation methods via the χ-comparison test (a derivative of the γ-evaluation) in worst-case-scenario geometries demonstrated an agreement between the two methods within 0.0784 cm (one pixel width) distance-to-agreement and up to a 1.8% dose difference. More clinically typical field sizes and source-to-detector distances were also tested, yielding at most a 1.0% dose difference and the same distance-to-agreement. Therefore, the assumption of parallel dose kernels has less than a 1.8% dosimetric effect in extreme cases and less than a 1.0% dosimetric effect in most clinically relevant situations and should be suitable for most clinical dosimetric applications. The

  10. Evaluation of usefulness of portal image using Electronic Portal Imaging Device (EPID) in the patients who received pelvic radiation therapy

    International Nuclear Information System (INIS)

    Kim, Woo Chul; Kim, Heon Jong; Park, Seong Young; Cho, Young Kap; Loh, John J. K.; Park, Won; Suh, Chang Ok; Kim, Gwi Eon

    1998-01-01

    To evaluate the usefulness of electronic portal imaging device through objective compare of the images acquired using an EPID and a conventional port film. From Apr. to Oct. 1997, a total of 150 sets of images from 20 patients who received radiation therapy in the pelvis area were evaluated in the Inha University Hospital and Severance Hospital. A dual image recording technique was devised to obtain both electronic portal images and port film images simultaneously with one treatment course. We did not perform double exposure. Five to ten images were acquired from each patient. All images were acquired from posteroanterior (PA) view except images from two patients. A dose rate of 100-300 MU/min and a 10-MV X-ray beam were used and 2-10 MUs were required to produce a verification image during treatment. Kodak diagnostic film with metal/film imaging cassette which was located on the top of the EPID detector was used for the port film. The source to detector distance was 140 cm. Eight anatomical landmarks (pelvic brim, sacrum, acetabulum, iliopectineal line, symphysis, ischium, obturator foramen, sacroiliac joint) were assessed. Four radiation oncologist joined to evaluate each image. The individual landmarks in the port film or in the EPID were rated-very clear (1), clear (2), visible (3), notclear (4), not visible (5). Using an video camera based EPID system, there was no difference of image quality between no enhanced EPID images and port film images. However, when we provided some change with window level for the portal image, the visibility of the sacrum and obturator foramen was improved in the portal images than in the port film images. All anatomical landmarks were more visible in the portal images than in the port film when we applied the CLAHE mode enhancement. The images acquired using an matrix ion chamber type EPID were also improved image quality after window level adjustment. The quality of image acquired using an electronic portal imaging device was

  11. Feasibility of megavoltage portal CT using an electronic portal imaging device (EPID) and a multi-level scheme algebraic reconstruction technique (MLS-ART)

    International Nuclear Information System (INIS)

    Guan, Huaiqun; Zhu, Yunping

    1998-01-01

    Although electronic portal imaging devices (EPIDs) are efficient tools for radiation therapy verification, they only provide images of overlapped anatomic structures. We investigated using a fluorescent screen/CCD-based EPID, coupled with a novel multi-level scheme algebraic reconstruction technique (MLS-ART), for a feasibility study of portal computed tomography (CT) reconstructions. The CT images might be useful for radiation treatment planning and verification. We used an EPID, set it to work at the linear dynamic range and collimated 6 MV photons from a linear accelerator to a slit beam of 1 cm wide and 25 cm long. We performed scans under a total of ∼200 monitor units (MUs) for several phantoms in which we varied the number of projections and MUs per projection. The reconstructed images demonstrated that using the new MLS-ART technique megavoltage portal CT with a total of 200 MUs can achieve a contrast detectibility of ∼2.5% (object size 5mmx5mm) and a spatial resolution of 2.5 mm. (author)

  12. Use of an electronic patient portal among the chronically ill: an observational study.

    Science.gov (United States)

    Riippa, Iiris; Linna, Miika; Rönkkö, Ilona; Kröger, Virpi

    2014-12-08

    Electronic patient portals may enhance effective interaction between the patient and the health care provider. To grasp the full potential of patient portals, health care providers need more knowledge on which patient groups prefer electronic services and how patients should be served through this channel. The objective of this study was to assess how chronically ill patients' state of health, comorbidities, and previous care are associated with their adoption and use of a patient portal. A total of 222 chronically ill patients, who were offered access to a patient portal with their health records and secure messaging with care professionals, were included in the study. Differences in the characteristics of non-users, viewers, and interactive users of the patient portal were analyzed before access to the portal. Patients' age, gender, diagnoses, levels of the relevant physiological measurements, health care contacts, and received physiological measurements were collected from the care provider's electronic health record. In addition, patient-reported health and patient activation were assessed by a survey. Despite the broad range of measures used to indicate the patients' state of health, the portal user groups differed only in their recorded diagnosis for hypertension, which was most common in the non-user group. However, there were significant differences in the amount of care received during the year before access to the portal. The non-user group had more nurse visits and more measurements of relevant physiological outcomes than viewers and interactive users. They also had fewer referrals to specialized care during the year before access to the portal than the two other groups. The viewers and the interactive users differed from each other significantly in the number of nurse calls received, the interactive users having more calls than the viewers. No significant differences in age, gender, or patient activation were detected between the user groups. Previous

  13. Generation of low KV x-ray portal images with mega-voltage electron beams

    International Nuclear Information System (INIS)

    Kenny, J.; Ebert, M.

    2004-01-01

    Full text: The increasing complexity of radiation therapy plans and reduced target margins, have made accurate localization of patients at treatment a crucial quality assurance issue. Mega-voltage portal images, the standard for treatment localization, are inherently low in contrast because x-ray attenuation at these energies is similar for most body tissues. Thus anatomical features are difficult to distinguish and match to features on a reference diagnostic image. This project investigates the possibly of using x-rays created by an external target placed in the path of a clinical mega-voltage electron beam. This target is optimised to produce a higher proportion of useful imaging x-rays in the range of 50-200kV. It is thought that a high efficiency Varian aSi500 amorphous silicon EPID will be sufficient to compensate for the very low efficiency of x-ray production. The project was undertaken with concurrent theoretical and experimental components. The former involved Monte Carlo models of low Z target design while in the later, experimental data was gathered to validate the model and explore the practical issues associated with electron mode image acquisition. A 6 MeV electron beam model for a Varian Clinac 21EX was developed with EGS4/BEAMnrc User Code and compared to measured beam data. Phase space data scored at the secondary collimator then became the input for simulations of a target placed in the accessory tray. Target materials were predominately low atomic number (Z) because a) production of high energy x-rays is minimized and, b) fewer low energy x-rays produced will be absorbed within the target. Photon and electron energy spectrums of the modified beam were evaluated for a range of target geometries. Ultimately, several materials were used in combination to optimise an x-ray yield for energies <200kV while removing electrons and very low energy x-rays, that contribute to patient dose but not to image formation. Low energy images of a PIPs EPID QA

  14. ESTERR-PRO: A Setup Verification Software System Using Electronic Portal Imaging

    Directory of Open Access Journals (Sweden)

    Pantelis A. Asvestas

    2007-01-01

    Full Text Available The purpose of the paper is to present and evaluate the performance of a new software-based registration system for patient setup verification, during radiotherapy, using electronic portal images. The estimation of setup errors, using the proposed system, can be accomplished by means of two alternate registration methods. (a The portal image of the current fraction of the treatment is registered directly with the reference image (digitally reconstructed radiograph (DRR or simulator image using a modified manual technique. (b The portal image of the current fraction of the treatment is registered with the portal image of the first fraction of the treatment (reference portal image by applying a nearly automated technique based on self-organizing maps, whereas the reference portal has already been registered with a DRR or a simulator image. The proposed system was tested on phantom data and on data from six patients. The root mean square error (RMSE of the setup estimates was 0.8±0.3 (mean value ± standard deviation for the phantom data and 0.3±0.3 for the patient data, respectively, by applying the two methodologies. Furthermore, statistical analysis by means of the Wilcoxon nonparametric signed test showed that the results that were obtained by the two methods did not differ significantly (P value >0.05.

  15. Dose patient verification during treatment using an amorphous silicon electronic portal imaging device in radiotherapy

    International Nuclear Information System (INIS)

    Berger, Lucie

    2006-01-01

    Today, amorphous silicon electronic portal imaging devices (aSi EPID) are currently used to check the accuracy of patient positioning. However, they are not use for dose reconstruction yet and more investigations are required to allow the use of an aSi EPID for routine dosimetric verification. The aim of this work is first to study the dosimetric characteristics of the EPID available at the Institut Curie and then, to check patient dose during treatment using these EPID. First, performance optimization of the Varian aS500 EPID system is studied. Then, a quality assurance system is set up in order to certify the image quality on a daily basis. An additional study on the dosimetric performance of the aS500 EPID is monitored to assess operational stability for dosimetry applications. Electronic portal imaging device is also a useful tool to improve IMRT quality control. The validation and the quality assurance of a portal dose image prediction system for IMRT pre-treatment quality control are performed. All dynamic IMRT fields are verified in clinical routine with the new method based on portal dosimetry. Finally, a new formalism for in vivo dosimetry using transit dose measured with EPID is developed and validated. The absolute dose measurement issue using aSi EPID is described and the midplane dose determination using in vivo dose measurements in combination with portal imaging is used with 3D-conformal-radiation therapy. (author) [fr

  16. Patient Use of the Electronic Communication Portal in Management of Type 2 Diabetes.

    Science.gov (United States)

    Peremislov, Diana

    2017-09-01

    High incidence and prevalence of type 2 diabetes require urgent attention to the management of this chronic disease. The purpose of this study was to explore electronic communication (e-communication) between patients with type 2 diabetes and their providers within the patient portal. Qualitative design with conventional content analysis techniques was used. A purposive random sample of 90 electronic medical record charts of patient-portal users with type 2 diabetes was subjected to a retrospective review. The sample mainly consisted of patients between the ages of 50 and 70 years, who were white, non-Hispanic, and English-speaking. The three major themes that emerged in e-communication via patient portal were inform theme, which was the most frequently identified theme; instruct/request theme, which was mainly used in initiation of e-communication; and the question theme. The patient portal was used primarily for requests by patients and instruction by providers, showing relatively short e-message encounters with a high number of partially completed encounters, frequent lack of resolution, and a low level of involvement of diabetes specialists in e-communication. There is a need to revise healthcare system guidelines on initiation and use of e-communication via patient portal and develop standardized templates to promote diabetes education in type 2 diabetes.

  17. Periodic quality control of a linear accelerator using electronic portal imaging

    International Nuclear Information System (INIS)

    Planes Meseguer, D.; Dorado Rodriguez, M. P.; Esposito, R. D.

    2011-01-01

    In this paper we present our solution for the realization of the monthly periodic quality control (CP) geometry - mechanical and multi leaf collimator (MLC), using the electronic system for portal imaging (EPI). We have developed specific programs created with free software. The monitoring results are automatically stored on our web server, along with other information generated in our service.

  18. Evaluation of image quality for various electronic portal imaging devices in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Son, Soon Yong; Choi, Kwan Woo [Dept. of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Kim, Jung Min [Dept. of College of Health Science, Radiologic Science, Korea University, Seoul (Korea, Republic of); and others

    2015-12-15

    In megavoltage (MV) radiotherapy, delivering the dose to the target volume is important while protecting the surrounding normal tissue. The purpose of this study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) using an edge block in megavoltage X-ray imaging (MVI). We used an edge block, which consists of tungsten with dimensions of 19 (thickness) × 10 (length) × 1 (width) cm3 and measured the pre-sampling MTF at 6 MV energy. Various radiation therapy (RT) devices such as TrueBeamTM (Varian), BEAMVIEWPLUS (Siemens), iViewGT (Elekta) and Clinac®iX (Varian) were used. As for MTF results, TrueBeamTM(Varian) flattening filter free(FFF) showed the highest values of 0.46 mm-1and1.40mm-1for MTF 0.5 and 0.1. In NPS, iViewGT (Elekta) showed the lowest noise distribution. In DQE, iViewGT (Elekta) showed the best efficiency at a peak DQE and 1 mm-1DQE of 0.0026 and 0.00014, respectively. This study could be used not only for traditional QA imaging but also for quantitative MTF, NPS, and DQE measurement for development of an electronic portal imaging device (EPID)

  19. Image timing and detector performance of a matrix ion-chamber electronic portal imaging device

    International Nuclear Information System (INIS)

    Greer, P.

    1996-01-01

    The Oncology Centre of Auckland Hospital recently purchased a Varian PortalVision TM electronic portal imaging device (EPID). Image acquisition times, input-output characteristics and contrast-detail curves of this matrix liquid ion-chamber EPID have been measured to examine the variation in imaging performance with acquisition mode. The variation in detector performance with acquisition mode has been examined. The HV cycle time can be increased to improve image quality. Consideration should be given to the acquisition mode and HV cycle time used when imaging to ensure adequate imaging performance with reasonable imaging time. (author)

  20. HPB Online: an electronic health education portal in Singapore.

    Science.gov (United States)

    Vijaya, K; Chan, S P; Ho, H P C; Lim, Y Y L; Lim, R

    2006-01-01

    In 2001, the Health Promotion Board (HPB) developed HPB Online, an internet-based health education portal to disseminate health messages. The objective of this article is to describe the structure of HPB Online, review its reach as a tool to deliver health information in Singapore, and discuss the advantages of using the internet to complement traditional media such as the television, newspapers and radio. Since its inception in 2001, the numbers of page-views, monthly visits and repeat visitors have increased markedly. The most popular webpages have consistently been Food Info Search. The average length of visit also showed a gradual increase during the study period, from about 11.0 minutes in January 2002 to 18.5 minutes in December 2004. The key advantage of using the HPB Online is that it allows quick delivery of information to the public and this is ideal for time-sensitive issues. It helps Singaporeans to make better informed decisions to maintain and to improve their health. With its high utilisation, the HPB will continue to use the internet as part of its multichannel marketing strategy to disseminate health information.

  1. Level-set segmentation of pulmonary nodules in megavolt electronic portal images using a CT prior

    International Nuclear Information System (INIS)

    Schildkraut, J. S.; Prosser, N.; Savakis, A.; Gomez, J.; Nazareth, D.; Singh, A. K.; Malhotra, H. K.

    2010-01-01

    Purpose: Pulmonary nodules present unique problems during radiation treatment due to nodule position uncertainty that is caused by respiration. The radiation field has to be enlarged to account for nodule motion during treatment. The purpose of this work is to provide a method of locating a pulmonary nodule in a megavolt portal image that can be used to reduce the internal target volume (ITV) during radiation therapy. A reduction in the ITV would result in a decrease in radiation toxicity to healthy tissue. Methods: Eight patients with nonsmall cell lung cancer were used in this study. CT scans that include the pulmonary nodule were captured with a GE Healthcare LightSpeed RT 16 scanner. Megavolt portal images were acquired with a Varian Trilogy unit equipped with an AS1000 electronic portal imaging device. The nodule localization method uses grayscale morphological filtering and level-set segmentation with a prior. The treatment-time portion of the algorithm is implemented on a graphical processing unit. Results: The method was retrospectively tested on eight cases that include a total of 151 megavolt portal image frames. The method reduced the nodule position uncertainty by an average of 40% for seven out of the eight cases. The treatment phase portion of the method has a subsecond execution time that makes it suitable for near-real-time nodule localization. Conclusions: A method was developed to localize a pulmonary nodule in a megavolt portal image. The method uses the characteristics of the nodule in a prior CT scan to enhance the nodule in the portal image and to identify the nodule region by level-set segmentation. In a retrospective study, the method reduced the nodule position uncertainty by an average of 40% for seven out of the eight cases studied.

  2. Maternity patients' access to their electronic medical records: use and perspectives of a patient portal.

    Science.gov (United States)

    Megan Forster, Megan; Dennison, Kerrie; Callen, Joanne; Andrew, Andrew; Westbrook, Johanna I

    Patients have been able to access clinical information from their paper-based health records for a number of years. With the advent of Electronic Medical Records (EMRs) access to this information can now be achieved online using a secure electronic patient portal. The purpose of this study was to investigate maternity patients' use and perceptions of a patient portal developed at the Mater Mothers' Hospital in Brisbane, Australia. A web-based patient portal, one of the first developed and deployed in Australia, was introduced on 26 June 2012. The portal was designed for maternity patients booked at Mater Mothers' Hospital, as an alternative to the paper-based Pregnancy Health Record. Through the portal, maternity patients are able to complete their hospital registration form online and obtain current health information about their pregnancy (via their EMR), as well as access a variety of support tools to use during their pregnancy such as tailored public health advice. A retrospective cross-sectional study design was employed. Usage statistics were extracted from the system for a one year period (1 July 2012 to 30 June 2013). Patients' perceptions of the portal were obtained using an online survey, accessible by maternity patients for two weeks in February 2013 (n=80). Descriptive statistics were employed to analyse the data. Between July 2012 and June 2013, 10,892 maternity patients were offered a patient portal account and access to their EMR. Of those 6,518 created one (60%; 6,518/10,892) and 3,104 went on to request access to their EMR (48%; 3,104/6,518). Of these, 1,751 had their access application granted by 30 June 2013. The majority of maternity patients submitted registration forms online via the patient portal (56.7%). Patients could view their EMR multiple times: there were 671 views of the EMR, 2,781 views of appointment schedules and 135 birth preferences submitted via the EMR. Eighty survey responses were received from EMR account holders, (response

  3. Periodic quality control of a linear accelerator using electronic portal imaging; Controles de calidad periodicos de un acelerador lineal utilizando el sistema electronico de imagenes portales

    Energy Technology Data Exchange (ETDEWEB)

    Planes Meseguer, D.; Dorado Rodriguez, M. P.; Esposito, R. D.

    2011-07-01

    In this paper we present our solution for the realization of the monthly periodic quality control (CP) geometry - mechanical and multi leaf collimator (MLC), using the electronic system for portal imaging (EPI). We have developed specific programs created with free software. The monitoring results are automatically stored on our web server, along with other information generated in our service.

  4. The stability of liquid-filled matrix ionization chamber electronic portal imaging devices for dosimetry purposes

    International Nuclear Information System (INIS)

    Louwe, R.J.W.; Tielenburg, R.; Ingen, K.M. van; Mijnheer, B.J.; Herk, M.B. van

    2004-01-01

    This study was performed to determine the stability of liquid-filled matrix ionization chamber (LiFi-type) electronic portal imaging devices (EPID) for dosimetric purposes. The short- and long-term stability of the response was investigated, as well as the importance of factors influencing the response (e.g., temperature fluctuations, radiation damage, and the performance of the electronic hardware). It was shown that testing the performance of the electronic hardware as well as the short-term stability of the imagers may reveal the cause of a poor long-term stability of the imager response. In addition, the short-term stability was measured to verify the validity of the fitted dose-response curve immediately after beam startup. The long-term stability of these imagers could be considerably improved by correcting for room temperature fluctuations and gradual changes in response due to radiation damage. As a result, the reproducibility was better than 1% (1 SD) over a period of two years. The results of this study were used to formulate recommendations for a quality control program for portal dosimetry. The effect of such a program was assessed by comparing the results of portal dosimetry and in vivo dosimetry using diodes during the treatment of 31 prostate patients. The improvement of the results for portal dosimetry was consistent with the deviations observed with the reproducibility tests in that particular period. After a correction for the variation in response of the imager, the average difference between the measured and prescribed dose during the treatment of prostate patients was -0.7%±1.5% (1 SD), and -0.6%±1.1% (1 SD) for EPID and diode in vivo dosimetry, respectively. It can be concluded that a high stability of the response can be achieved for this type of EPID by applying a rigorous quality control program

  5. Using an electronic portal imaging device for exit dose measurements in radiotherapy

    International Nuclear Information System (INIS)

    Ganowicz, M.; Wozniak, B.; Bekman, A.; Maniakowski, Z.

    2003-01-01

    To present a method of determining the exit dose with the use of an electronic portal imaging device (EPID). The device used was the Portal Vision LC250 (Varian). The EPID signals on the central beam axis have been related to the exit dose. The exit dose measurements were performed with the ionisation chamber in the slab phantom at the distance of dose maximum from the exit surface of the phantom. EPID reading was investigated as a function of field size, phantom thickness and source-detector distance. The relation between dose rate and the EPID reading is described with empirical functions applicable to the obtained data. The exit dose is calculated from the EPID reading as a product of the calibration factor and appropriate correction factors. The determination of the exit dose rate from the EPID signal requires the knowledge of many parameters and earlier determination of essential characteristics. (author)

  6. An image correlation procedure for digitally reconstructed radiographs and electronic portal images

    International Nuclear Information System (INIS)

    Dong, Lei; Boyer, Arthur L.

    1995-01-01

    Purpose: To study a procedure that uses megavoltage digitally reconstructed radiographs (DRRs) calculated from patient's three-dimensional (3D) computed tomography (CT) data as a reference image for correlation with on-line electronic portal images (EPIs) to detect patient setup errors. Methods and Materials: Megavoltage DRRs were generated by ray tracing through a modified volumetric CT data set in which CT numbers were converted into linear attenuation coefficients for the therapeutic beam energy. The DRR transmission image was transformed to the grayscale window of the EPI by a histogram-matching technique. An alternative approach was to calibrate the transmission DRR using a measured response curve of the electronic portal imaging device (EPID). This forces the calculated transmission fluence values to be distributed in the same range as that of the EPID image. A cross-correlation technique was used to determine the degree of alignment of the patient anatomy found in the EPID image relative to the reference DRR. Results: Phantom studies demonstrated that the correlation procedure had a standard deviation of 0.5 mm and 0.5 deg. in aligning translational shifts and in-plane rotations. Systematic errors were found between a reference DRR and a reference EPID image. The automated grayscale image-correlation process was completed within 3 s on a workstation computer or 12 s on a PC. Conclusion: The alignment procedure allows the direct comparison of a patient's treatment portal designed with a 3D planning computer with a patient's on-line portal image acquired at the treatment unit. The image registration process is automated to the extent that it requires minimal user intervention, and it is fast and accurate enough for on-line clinical applications

  7. Online versus offline corrections: opposition or evolution? A comparison of two electronic portal imaging approaches for locally advanced prostate cancer

    International Nuclear Information System (INIS)

    Middleton, Mark; Medwell, Steve; Wong, Jacky; Lynton-Moll, Mary; Rolfo, Aldo; See Andrew; Joon, Michael Lim

    2006-01-01

    Given the onset of dose escalation and increased planning target volume (PTV) conformity, the requirement of accurate field placement has also increased. This study compares and contrasts a combination offline/online electronic portal imaging (EPI) device correction with a complete online correction protocol and assesses their relative effectiveness in managing set-up error. Field placement data was collected on patients receiving radical radiotherapy to the prostate. Ten patients were on an initial combination offline/online correction protocol, followed by another 10 patients on a complete online correction protocol. Analysis of 1480 portal images from 20 patients was carried out, illustrating that a combination offline/online approach can be very effective in dealing with the systematic component of set-up error, but it is only when a complete online correction protocol is employed that both systematic and random set-up errors can be managed. Now, EPI protocols have evolved considerably and online corrections are a highly effective tool in the quest for more accurate field placement. This study discusses the clinical workload impact issues that need to be addressed in order for an online correction protocol to be employed, and addresses many of the practical issues that need to be resolved. Management of set-up error is paramount when seeking to dose escalate and only an online correction protocol can manage both components of set-up error. Both systematic and random errors are important and can be effectively and efficiently managed

  8. Automated detection of a prostate Ni-Ti stent in electronic portal images

    OpenAIRE

    Carl, Jesper; Nielsen, Henning; Nielsen, Jane; Lund, Bente; Larsen, Erik Hoejkjaer

    2006-01-01

      Udgivelsesdato: DEC  Planning target volumes (PTV) in fractionated radiotherapy still have to be outlined with wide margins to the clinical target volume due to uncertainties arising from daily shift of the prostate position. A recently proposed new method of visualization of the prostate is based on insertion of a thermo-expandable Ni-Ti stent. The current study proposes a new detection algorithm for automated detection of the Ni-Ti stent in electronic portal images. The algorithm is ba...

  9. Dosimetric characterization of an electronic portal imaging device (EPID) and development of a portal dosimetry simple model; Caracterizacion dosimetrica de un dispositivo electronico de imagen portal (EPID) y desarrollo de un modelo simple de dosimetria portal

    Energy Technology Data Exchange (ETDEWEB)

    Ripol ValentIn, O.; GarcIa Romero, A.; Hernandez Vitoria, A.; Jimenez Albericio, J.; Cortes Rodicio, J.; Millan Cebrian, E.; Ruiz Manzano, P.; Canellas Anoz, M.

    2010-07-01

    The use of the Electronic Portal Imaging Devices (EPID) for the quality control of linear accelerators of electrons is increasingly extended in practice. In this work the dosimetric characteristics of an EPID OptiVue{sup TM}1000 ST were studied and a friendly and simple method for the absorbed dose calibration was suggested. This method is based on a simple mathematical model, including: an absorbed dose transformation coefficient and image lag and field shape corrections. Software tools were developed in order to process the information and the results were validated by comparing them with the measured data with ionization chambers. The studied device showed suitable characteristics for its use for EPID dosimetry and the calculated results fitted satisfactorily with the dose planes obtained with the ionization chambers. Keeping in mind the model limitations, we concluded that it is possible to start the use of the EPID for the accelerator quality control and improvements for the current model should be studied, as well as other suitable applications: e.g. the Intensity Modulated Radiation Therapy (IMRT) treatment verification procedures. (Author).

  10. Assessment of Set-up Accuracy in Tangential Breast Treatment Using Electronic Portal Imaging Device

    International Nuclear Information System (INIS)

    Lee, Byung Koo; Kang, Soo Man

    2012-01-01

    The aim of this study was to investigate the setup accuracy for tangential breast treatment patients using electronic portal image and 2-D reconstruction image Twenty two patients undergoing tangential breast treatment. To explore the setup accuracy, distances between chosen landmarks were taken as reference parameters. The difference between measured reference parameters on simulation films and electronic portal images (EPIs) was calculated as the setup error. A total of 22 simulation films and 110 EPIs were evaluated. In the tangential fields, the calculated reference parameters were the central lung distance (CLD), central soft-tissue distance (CSTD), and above lung distance (ALD), below lung distance (BLD). In the medial tangential field, the average difference values for these parameters were 1.0, -6.4, -2.1 and 2.0, respectively; and the values were 1.5, 2.3, 4.1 and 1.1, respectively. In the lateral tangential field, the average difference values for these parameters were -1.5, -4.3, -2.7 and -1.3, respectively; and the values were 3.3, 2.1, 2.9 and 2.5, respectively. CLD, CSTD, ALD and BLD in the tangential fields are easily identifiable and are helpful for detecting setup errors using EPIs in patients undergoing tangential breast radiotherapy treatment.

  11. Assessment of Set-up Accuracy in Tangential Breast Treatment Using Electronic Portal Imaging Device

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Koo [Dept. of Radiation Oncology, Korea University Anam Hospital, Seoul (Korea, Republic of); Kang, Soo Man [Dept. of Radiation Oncology, Korea University Gospel Hospital, Seoul (Korea, Republic of)

    2012-09-15

    The aim of this study was to investigate the setup accuracy for tangential breast treatment patients using electronic portal image and 2-D reconstruction image Twenty two patients undergoing tangential breast treatment. To explore the setup accuracy, distances between chosen landmarks were taken as reference parameters. The difference between measured reference parameters on simulation films and electronic portal images (EPIs) was calculated as the setup error. A total of 22 simulation films and 110 EPIs were evaluated. In the tangential fields, the calculated reference parameters were the central lung distance (CLD), central soft-tissue distance (CSTD), and above lung distance (ALD), below lung distance (BLD). In the medial tangential field, the average difference values for these parameters were 1.0, -6.4, -2.1 and 2.0, respectively; and the values were 1.5, 2.3, 4.1 and 1.1, respectively. In the lateral tangential field, the average difference values for these parameters were -1.5, -4.3, -2.7 and -1.3, respectively; and the values were 3.3, 2.1, 2.9 and 2.5, respectively. CLD, CSTD, ALD and BLD in the tangential fields are easily identifiable and are helpful for detecting setup errors using EPIs in patients undergoing tangential breast radiotherapy treatment.

  12. Preferences of Current and Potential Patients and Family Members Regarding Implementation of Electronic Communication Portals in Intensive Care Units.

    Science.gov (United States)

    Brown, Samuel M; Bell, Sigall K; Roche, Stephanie D; Dente, Erica; Mueller, Ariel; Kim, Tae-Eun; O'Reilly, Kristin; Lee, Barbara Sarnoff; Sands, Ken; Talmor, Daniel

    2016-03-01

    The quality of communication with patients and family members in intensive care units (ICUs) is a focus of current interest for clinical care improvement. Electronic communication portals are commonly used in other healthcare settings to improve communication. We do not know whether patients and family members desire such portals in ICUs, and if so, what functionality they should provide. To define interest in and desired elements of an electronic communication portal among current and potential ICU patients and their family members. We surveyed, via an Internet panel, 1,050 English-speaking adults residing in the United States with a personal or family history of an ICU admission within 10 years (cohort A) and 1,050 individuals without a history of such admission (cohort B). We also administered a survey instrument in person to 105 family members of patients currently admitted to ICUs at an academic medical center in Boston (cohort C). Respondents, especially current ICU family members, supported an electronic communication portal, including access via an electronic tablet. They wanted at least daily updates, one-paragraph summaries of family meetings including a list of key decisions made, and knowledge of the role and experience of treating clinicians. Overall, they preferred detailed rather than "big picture" information. Respondents were generally comfortable sharing information with their family members. Preferences regarding a communication portal varied significantly by age, sex, ethnicity, and prior experience with ICU hospitalization. Electronic communication portals appear welcome in contemporary ICUs. Frequent updates, knowledge about the professional qualifications of clinicians, detailed medical information, and documentation of family meetings are particularly desired.

  13. Analysis of interfraction and intrafraction variation during tangential breast irradiation with an electronic portal imaging device

    International Nuclear Information System (INIS)

    Smith, Ryan P.; Bloch, Peter; Harris, Eleanor E.; McDonough, James; Sarkar, Abhirup; Kassaee, Alireza; Avery, Steven; Solin, Lawrence J.

    2005-01-01

    Purpose: To evaluate the daily setup variation and the anatomic movement of the heart and lungs during breast irradiation with tangential photon beams, as measured with an electronic portal imaging device. Methods and materials: Analysis of 1,709 portal images determined changes in the radiation field during a treatment course in 8 patients. Values obtained for every image included central lung distance (CLD) and area of lung and heart within the irradiated field. The data from these measurements were used to evaluate variation from setup between treatment days and motion due to respiration and/or patient movement during treatment delivery. Results: The effect of respiratory motion and movement during treatment was minimal: the maximum range in CLD for any patient on any day was 0.25 cm. The variation caused by day-to-day setup variation was greater, with CLD values for patients ranging from 0.59 cm to 2.94 cm. Similar findings were found for heart and lung areas. Conclusions: There is very little change in CLD and corresponding lung and heart area during individual radiation treatment fractions in breast tangential fields, compared with a relatively greater amount of variation that occurs between days

  14. Transglutaminase 2 is needed for the formation of an efficient phagocyte portal in macrophages engulfing apoptotic cells.

    Science.gov (United States)

    Tóth, Beáta; Garabuczi, Eva; Sarang, Zsolt; Vereb, György; Vámosi, György; Aeschlimann, Daniel; Blaskó, Bernadett; Bécsi, Bálint; Erdõdi, Ferenc; Lacy-Hulbert, Adam; Zhang, Ailiang; Falasca, Laura; Birge, Raymond B; Balajthy, Zoltán; Melino, Gerry; Fésüs, László; Szondy, Zsuzsa

    2009-02-15

    Transglutaminase 2 (TG2), a protein cross-linking enzyme with many additional biological functions, acts as coreceptor for integrin beta(3). We have previously shown that TG2(-/-) mice develop an age-dependent autoimmunity due to defective in vivo clearance of apoptotic cells. Here we report that TG2 on the cell surface and in guanine nucleotide-bound form promotes phagocytosis. Besides being a binding partner for integrin beta(3), a receptor known to mediate the uptake of apoptotic cells via activating Rac1, we also show that TG2 binds MFG-E8 (milk fat globulin EGF factor 8), a protein known to bridge integrin beta(3) to apoptotic cells. Finally, we report that in wild-type macrophages one or two engulfing portals are formed during phagocytosis of apoptotic cells that are characterized by accumulation of integrin beta(3) and Rac1. In the absence of TG2, integrin beta(3) cannot properly recognize the apoptotic cells, is not accumulated in the phagocytic cup, and its signaling is impaired. As a result, the formation of the engulfing portals, as well as the portals formed, is much less efficient. We propose that TG2 has a novel function to stabilize efficient phagocytic portals.

  15. Impact and user satisfaction of a clinical information portal embedded in an electronic health record.

    Science.gov (United States)

    Tannery, Nancy H; Epstein, Barbara A; Wessel, Charles B; Yarger, Frances; LaDue, John; Klem, Mary Lou

    2011-01-01

    In 2008, a clinical information tool was developed and embedded in the electronic health record system of an academic medical center. In 2009, the initial information tool, Clinical-e, was superseded by a portal called Clinical Focus, with a single search box enabling a federated search of selected online information resources. To measure the usefulness and impact of Clinical Focus, a survey was used to gather feedback about users' experience with this clinical resource. The survey determined what type of clinicians were using this tool and assessed user satisfaction and perceived impact on patient care decision making. Initial survey results suggest the majority of respondents found Clinical Focus easy to navigate, the content easy to read, and the retrieved information relevant and complete. The majority would recommend Clinical Focus to their colleagues. Results indicate that this tool is a promising area for future development.

  16. Evaluation of set-of errors in pelvic irradiation with electronic portal imaging device

    International Nuclear Information System (INIS)

    Wu Xiaoying; Zhang Zhen; Wang Wenchao; Ren Jun; Guo Xiaomei; Lu Huizhong

    2007-01-01

    Objective: Evaluate the systematic and random set-up error in the pelvic irradiation u- sing electronic portal imaging device(EPID) to provide institution-specific margin for PTV design in pelvic cancer treatment planning with 3D conformal therapy and/or IMRT. Methods: From May to August 2005, twelve patients who received pelvic irradiation, were involved in this study. CT simulations were performed and DRRs were generated as the reference images. Ant-post and lateral portal images were taken daily, and total of 244 sets of EPID images were collected for the whole group. The translational shifts along right-left, superior-inferior and anterior-posterior directions were calculated with aligning the pelvic bony structures on the DRRs and electronic portal images. The systematic and random setup errors were evaluated based on the 244 sets of data. PTV margin was assessed assuming target rotation was negligible. Results: In the right- left (R-L), superior-inferior (S-I) and anterior-posterior (A-P) directions, the maximum shifts were 9.9, 14.0 and 21.1 mm and the systematic setup errors were 0.5, 0.2 and 2.3 mm respectively. For all 244 sets of data in this study, the frequency of the shift larger than 10 mm were 0% (R-L), 1% (S-I) and 3% (A -P); and in R-L and S-I direction, 92% and 91% of the times the shift was smaller than 5 mm. However, only 79% of the times the A-P shift was less than 5 mm. Conclusions: It is suggested in this study that in order to achieve a target coverage of better than 95% of the times throughout the pelvic irradiation in our institution, a 5 mm PTV margin in right-left and superior-inferior directions is required, however, the anterior-posterior margin needs to be increased to at least 10 mm. One needs to be cautious though when applying the PTV margin derived from small sample of patient population to individual patient. (authors)

  17. Overview of 3-year experience with large-scale electronic portal imaging device-based 3-dimensional transit dosimetry

    NARCIS (Netherlands)

    Mijnheer, Ben J.; González, Patrick; Olaciregui-Ruiz, Igor; Rozendaal, Roel A.; van Herk, Marcel; Mans, Anton

    2015-01-01

    To assess the usefulness of electronic portal imaging device (EPID)-based 3-dimensional (3D) transit dosimetry in a radiation therapy department by analyzing a large set of dose verification results. In our institution, routine in vivo dose verification of all treatments is performed by means of 3D

  18. Validation of quality control tests of a multi leaf collimator using electronic portal image devices and commercial software; Validacion de unas pruebas de control de calidad del colimador multilamina utilizando dispositivos electronicos de imagen portal y una aplicacion comercial

    Energy Technology Data Exchange (ETDEWEB)

    Latorre-Musoll, A.; Jornet Sala, N.; Carrasco de Fez, P.; Edualdo Puell, T.; Ruiz Martinez, A.; Ribas Morales, M.

    2013-07-01

    We describe a daily quality control procedure of the multi leaf collimator (MLC) based on electronic portal image devices and commercial software. We designed tests that compare portal images of a set of static and dynamic MLC configurations to a set of reference images using commercial portal dosimetry software. Reference images were acquired using the same set of MLC configurations after the calibration of the MLC. To assess the sensitivity to detect MLC under performances, we modified the MLC configurations by inserting a range of leaf position and speed errors. Distance measurements on portal images correlated with leaf position errors down to 0.1 mm in static MLC configurations. Dose differences between portal images correlated both with speed errors down to 0.5% of the nominal leaf velocities and with leaf position errors down to 0.1 mm in dynamic MLC configurations. The proposed quality control procedure can assess static and dynamic MLC configurations with high sensitivity and reliability. (Author)

  19. Evaluation of respiratory movement during gated radiotherapy using film and electronic portal imaging

    International Nuclear Information System (INIS)

    Ford, E.C.; Mageras, G.S.; Yorke, E.; Rosenzweig, K.E.; Wagman, R.; Ling, C.C.

    2002-01-01

    Purpose: To evaluate the effectiveness of a commercial system in reducing respiration-induced treatment uncertainty by gating the radiation delivery. Methods and Materials: The gating system considered here measures respiration from the position of a reflective marker on the patient's chest. Respiration-triggered planning CT scans were obtained for 8 patients (4 lung, 4 liver) at the intended phase of respiration (6 at end expiration and 2 at end inspiration). In addition, fluoroscopic movies were recorded simultaneously with the respiratory waveform. During the treatment sessions, gated localization films were used to measure the position of the diaphragm relative to the vertebral bodies, which was compared to the reference digitally reconstructed radiograph derived from the respiration-triggered planning CT. Variability was quantified by the standard deviation about the mean position. We also assessed the interfraction variability of soft tissue structures during gated treatment in 2 patients using an amorphous silicon electronic portal imaging device. Results: The gated localization films revealed an interfraction patient-averaged diaphragm variability of 2.8±1.0 mm (error bars indicate standard deviation in the patient population). The fluoroscopic data yielded a patient-averaged intrafraction diaphragm variability of 2.6±1.7 mm. With no gating, this intrafraction excursion became 6.9±2.1 mm. In gated localization films, the patient-averaged mean displacement of the diaphragm from the planning position was 0.0±3.9 mm. However, in 4 of the 8 patients, the mean (over localization films) displacement was >4 mm, indicating a systematic displacement in treatment position from the planned one. The position of soft tissue features observed in portal images during gated treatments over several fractions showed a mean variability between 2.6 and 5.7 mm. The intrafraction variability, however, was between 0.6 and 1.4 mm, indicating that most of the variability was

  20. Observer variability when evaluating patient movement from electronic portal images of pelvic radiotherapy fields

    International Nuclear Information System (INIS)

    Geraint Lewis, D.; Ryan, Karen R.; Smith, Cyril W.

    2005-01-01

    Background and purpose: A study has been performed to evaluate inter-observer variability when assessing pelvic patient movement using an electronic portal imaging device (EPID). Materials and methods: Four patient image sets were used with 3-6 portal images per set. The observer group consisted of nine radiographers with 3-18 months clinical EPID experience. The observers outlined bony landmarks on a digital simulator image and used matching software to evaluate field placement errors (FPEs) on each portal image relative to the reference simulator image. Data were evaluated statistically, using a two-component analysis of variance technique, to quantify both the inter-observer variability in evaluating FPEs and inter-fraction variability in patient position relative to the residuals of the analysis. Intra-observer variability was also estimated using four of the observers carrying out three sets of repeat readings. Results: Eight sets of variance data were analysed, based on FPEs in two orthogonal directions for each of the four patient image sets studied. Initial analysis showed that both inter-observer variation and inter-fraction-patient position variation were statistically significant (P<0.05) in seven of the eight cases evaluated. The averaged root-mean-square (RMS) deviation of the observers from the group mean was 1.1 mm, with a maximum deviation of 5.0 mm recorded for an individual observer. After additional training and re-testing of two of the observers who recorded the largest deviations from the group mean, a subsequent analysis showed the inter-observer variability for the group to be significant in only three of the eight cases, with averaged RMS deviation reduced to 0.5 mm, with a maximum deviation of 2.7 mm. The intra-observer variability was 0.5 mm, averaged over the four observers tested. Conclusions: We have developed a quantitative approach to evaluate inter-observer variability in terms of its statistical significance compared to inter

  1. Treatment verification with megavoltage electronic portal imaging applied to the tomotherapy concept

    International Nuclear Information System (INIS)

    Hesse, B.-M.; Spies, L.; Groh, B.; Doll, J.; Haering, P.; Hoever, K. H.

    1997-01-01

    Purpose: A new treatment strategy called Tomotherapy, introduced by T. R. Mackie et al. in 1993, was designed to perform a dynamic conformal treatment technique in precision radiotherapy. This technique delivers sliced intensity-modulated radiation fields to achieve best tumor control while sparing neighbouring sensitive normal tissue and organs at risk. The beam continuously revolves around the patient similarly to a spiral-CT while the patient is moved through the bore of the gantry. As a first step towards the realization of such a concept with a linear accelerator (Siemens Mevatron Experimental) used in clinical routine, we focused on treatment setup and dose verification. In tomotherapy, an actual CT data set is needed for patient positioning and for the verification of the absorbed dose, also, the dose transmitted through the patient must be known. This makes possible both routine tomographic treatment setup verification and tomographic dose reconstruction of the actual delivered dose. Materials and Methods: All measurements were performed with a megavoltage electronic portal imaging device of Wellhoefer TM (BIS-710). The BIS-710 detector is based on a scintillation foil and contains a camera for 10-bit digital data output. The dimension of the detector plane is 512 x 512 pixels with a pixel size of 0.6 mm in each direction. The BIS-710 was developed especially for quantitative dose measuring, whereas most of the existing Portal Imaging Systems are used for image display only. To examine the properties of the BIS-710 concerning tomographical reconstruction with a therapeutic 6 MV X-ray beam, a tissue-equivalent Alderson head phantom was rotated stepwise across a stationary beam between the collimator and the detector plane. The influence of scattering can be estimated by comparing measurements which were taken with a homogeneous phantom which is invariant under rotation with a calculated exit dose distribution using a simple exponential law for the

  2. Assessment of dosimetrical performance in 11 Varian a-Si500 electronic portal imaging devices

    International Nuclear Information System (INIS)

    Kavuma, Awusi; Glegg, Martin; Currie, Garry; Elliott, Alex

    2008-01-01

    Dosimetrical characteristics of 11 Varian a-Si-500 electronic portal imaging devices (EPIDs) in clinical use for periods ranging between 10 and 86 months were investigated for consistency of performance and portal dosimetry implications. Properties studied include short-term reproducibility, signal linearity with monitor units, response to reference beam, signal uniformity across the detector panel, signal dependence on field size, dose-rate influence, memory effects and image profiles as a function of monitor units. The EPID measurements were also compared with those of the ionization chambers' to ensure stability of the linear accelerators. Depending on their clinical installation date, the EPIDs were interfaced with one of the two different acquisition control software packages, IAS2/IDU-II or IAS3/IDU-20. Both the EPID age and image acquisition system influenced the dosimetric characteristics with the newer version (IAS3 with IDU-20) giving better data reproducibility and linearity fit than the older version (IAS2 with IDU-II). The relative signal response (uniformity) after 50 MU was better than 95% of the central value and independent of detector. Sensitivity for all EPIDs reduced continuously with increasing dose rates for the newer image acquisition software. In the dose-rate range 100-600 MU min -1 , the maximum variation in sensitivity ranged between 1 and 1.8% for different EPIDs. For memory effects, the increase in the measured signal at the centre of the irradiated field for successive images was within 1.8% and 1.0% for the older and newer acquisition systems, respectively. Image profiles acquired at a lower MU in the radial plane (gun-target) had gradients in measured pixel values of up to 25% for the older system. Detectors with software/hardware versions IAS3/IDU-20 have a high degree of accuracy and are more suitable for routine quantitative IMRT dosimetrical verification.

  3. Utilization of an electronic portal imaging device for measurement of dynamic wedge data

    International Nuclear Information System (INIS)

    Elder, Eric S.; Miner, Marc S.; Butker, Elizabeth K.; Sutton, Danny S.; Davis, Lawrence W.

    1996-01-01

    Purpose/Objective: Due to the motion of the collimator during dynamic wedge treatments, the conventional method of collecting comprehensive wedge data with a water tank and a scanning ionization chamber is obsolete. It is the objective of this work to demonstrate the use of an electronic portal imaging device (EPID) and software to accomplish this task. Materials and Methods: A Varian Clinac[reg] 2300 C/D, equipped with a PortalVision TM EPID and Dosimetry Research Mode experimental software, was used to produce the radiation field. The Dosimetry Research Mode experimental software allows for a band of 10 of 256 high voltage electrodes to be continuously read and averaged by the 256 electrometer electrodes. The file that is produced contains data relating to the integrated ionization at each of the 256 points, essentially the cross plane beam profile. Software was developed using Microsoft C ++ to reformat the data for import into a Microsoft Excel spreadsheet allowing for easy mathematical manipulation and graphical display. Beam profiles were measured by the EPID with a 100 cm TSD for various field sizes. Each field size was measured open, steel wedged, and dynamically wedged. Scanning ionization chamber measurements performed in a water tank were compared to the open and steel wedged fields. Ionization chamber measurements taken in a water tank were compared with the dynamically wedged measurements. For the EPID measurements the depth was varied using Gammex RMI Solid Water TM placed directly above the EPID sensitive volume. Bolus material was placed between the Solid Water TM and the EPID to avoid an air gap. Results: Comparison of EPID measurements with those from an ion chamber in a water tank showed a discrepancy of ∼5%. Scans were successfully obtained for open, steel wedged and dynamically wedged beams. Software has been developed to allow for easy graphical display of beam profiles. Conclusions: Measurement of dynamic wedge data proves to be easily

  4. [Efficacy and efficiency of searches for a physician using physician search and evaluation portals in comparison with Google].

    Science.gov (United States)

    Sander, U; Emmert, M; Grobe, T G

    2013-06-01

    The Internet provides ways for patients to obtain information about doctors. The study poses the question whether it is possible and how long it takes to find a suitable doctor with an Internet search. It focuses on the effectiveness and efficiency of the search. Specialised physician rating and searching portals and Google are analysed when used to solve specific tasks. The behaviour of volunteers when searching a suitable ophthalmologist, dermatologist or dentist was observed in a usability lab. Additionally, interviews were carried out by means of structured questionnaires to measure the satisfaction of the users with the search and their results. Three physician rating and searching portals that are frequently used in Germany (Jameda.de, DocInsider.de and Arztauskunft.de) were analysed as well as Google. When using Arztauskunft and Google most users found an appropriate physician. When using Docinsider or Jameda they found fewer doctors. Additionally, the time needed to locate a suitable doctor when using Docinsider and Jameda was higher compared to the time needed when using the Arztauskunft and Google. The satisfaction of users who used Google was significantly higher in comparison to those who used the specialised physician rating and searching portals. It emerged from this study that there is no added value when using specialised physician rating and searching portals compared to using the search engine Google when trying to find a doctor having a particular specialty. The usage of several searching portals is recommended to identify as many suitable doctors as possible. © Georg Thieme Verlag KG Stuttgart · New York.

  5. High-efficient electron linacs

    International Nuclear Information System (INIS)

    Glavatskikh, K.V.; Zverev, B.V.; Kalyuzhnyj, V.E.; Morozov, V.L.; Nikolaev, S.V.; Plotnikov, S.N.; Sobenin, N.P.; Vovna, V.A.; Gryzlov, A.V.

    1993-01-01

    Comparison analysis of ELA on running and still waves designed for 10 MeV energy and with high efficiency is carried out. It is shown, that from the point of view of dimensions ELA with a still wave or that of a combined type is more preferable. From the point of view of impedance characteristics in any variant with application of magnetron as HF-generator it is necessary to implement special requirements to the accelerating structure if no ferrite isolation is provided in HF-channel. 3 refs., 4 figs., 1 tab

  6. NOTE: A method for controlling image acquisition in electronic portal imaging devices

    Science.gov (United States)

    Glendinning, A. G.; Hunt, S. G.; Bonnett, D. E.

    2001-02-01

    Certain types of camera-based electronic portal imaging devices (EPIDs) which initiate image acquisition based on sensing a change in video level have been observed to trigger unreliably at the beginning of dynamic multileaf collimation sequences. A simple, novel means of controlling image acquisition with an Elekta linear accelerator (Elekta Oncology Systems, Crawley, UK) is proposed which is based on illumination of a photodetector (ORP-12, Silonex Inc., Plattsburgh, NY, USA) by the electron gun of the accelerator. By incorporating a simple trigger circuit it is possible to derive a beam on/off status signal which changes at least 100 ms before any dose is measured by the accelerator. The status signal does not return to the beam-off state until all dose has been delivered and is suitable for accelerator pulse repetition frequencies of 50-400 Hz. The status signal is thus a reliable means of indicating the initiation and termination of radiation exposure, and thus controlling image acquisition of such EPIDs for this application.

  7. Characterization of an electronic system for Image acquisition portal to open field dosimetry; Caracterizacao de um sistema eletronico de aquisicao de imagem portal para dosimetria em radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Barbi, Gustavo L.; Oliveira, Harley F.; Bertucci, Edenyse C.; Amaral, Leonardo L.; Borges, Leandro F., E-mail: gustavobarbi@usp.br [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Hospital das Clinicas. Centro de Ciencias das Imagens e Fisica Medica

    2012-08-15

    The objective was to characterize and enable an electronic portal imaging device (EPID) to use like a portal dosimetry device - PDI, in non-transit mode, without interposition of scattering between the beam and EPID for measurement to open fields. The images as well as the DICOM header data are extracted from software ImageJ and the information are used in the basic algorithm for converting pixel to dose. The linearity and reproducibility of response were analyzed, and the maximum deviation found of 2,3% to 800 monitor units (MU) for linearity and -0,9% for reproducibility of signal measured daily. A 512x512 matrix with a resolution of 0,8mm was established to restore the shape of beam from the image. The field size dependence was evaluated, by obtaining the ratio of total scattering of ionization chamber and EPID. Finally, a calibration factor of 28470.88{+-}170.73 pixel/cGy was established for the central area of the image. Comparative analyzes between the PDI, radiochromic film and array of ionization chambers (MatriXX) showed good agreement for fields greater then 5 x 5 cm{sup 2} to reestablishment of form field and dose, however, for fields between 3x3 cm{sup 2} and 5x5 cm{sup 2}, the agreement to shape of beam was best established by film. (author)

  8. Development of a model using narrow slit beam profiles to account for the backscatter response of an amorphous silicon electronic portal imaging device

    International Nuclear Information System (INIS)

    Maria Das, K.J.; Ostapiak, Orest

    2008-01-01

    An electronic portal imaging device (EPID), currently used for determining proper patient placement during irradiation in a radiotherapy treatment, can also be used for the purpose of pre- treatment IMRT QA. However, the Varian aS500 portal imager exhibits dosimetric artifacts caused by non-uniform backscatter from mechanical support structures located behind the imager

  9. Prostate position relative to pelvic bony anatomy based on intraprostatic gold markers and electronic portal imaging

    International Nuclear Information System (INIS)

    Schallenkamp, John M.; Herman, Michael G.; Kruse, Jon J.; Pisansky, Thomas M.

    2005-01-01

    Purpose: To describe the relative positions and motions of the prostate, pelvic bony anatomy, and intraprostatic gold fiducial markers during daily electronic portal localization of the prostate. Methods and Materials: Twenty prostate cancer patients were treated supine with definitive external radiotherapy according to an on-line target localization protocol using three or four intraprostatic gold fiducial markers and an electronic portal imaging device. Daily pretherapy and through-treatment electronic portal images (EPIs) were obtained for each of four treatment fields. The patients' pelvic bony anatomy, intraprostatic gold markers, and a best visual match to the target (i.e., prostate) were identified on simulation digitally reconstructed radiographs and during daily treatment setup and delivery. These data provided quantitative inter- and intrafractional analysis of prostate motion, its position relative to the bony anatomy, and the individual intraprostatic fiducial markers. Treatment planning margins, with and without on-line localization, were subsequently compared. Results: A total of 22,266 data points were obtained from daily pretherapy and through-treatment EPIs. The pretherapy three-dimensional (3D) average displacement of the fiducial markers, as a surrogate for the prostate, was 5.6 mm, which improved to 2.8 mm after use of the localization protocol. The bony anatomy 3D average displacement was 4.4 mm both before and after localization to the prostate (p = 0.46). Along the superior-inferior (SI), anterior-posterior (AP), and right-left (RL) axes, the average prostate displacement improved from 2.5, 3.7, and 1.9 mm, respectively, before localization to 1.4, 1.6, and 1.1 mm after (all p < 0.001). The pretherapy to through-treatment position of the bony landmarks worsened from 1.7 to 2.5 mm (p < 0.001) in the SI axis, remained statistically unchanged at 2.8 mm (p = 0.39) in the AP axis, and improved from 2.0 to 1.2 mm in the RL axis (p < 0.001). There

  10. Clinician Perspectives on an Electronic Portal to Improve Communication with Patients and Families in the Intensive Care Unit.

    Science.gov (United States)

    Bell, Sigall K; Roche, Stephanie D; Johansson, Anna C; O'Reilly, Kristin P; Lee, Barbara S; Sands, Kenneth E; Talmor, Daniel S; Brown, Samuel M

    2016-12-01

    Communication in the intensive care unit (ICU) often falls short of patient and family needs, putting them at risk for significant physical and emotional harm. As electronic patient portals rapidly evolve, one designed specifically for the ICU might potentially enhance communication among patients, family members, and clinicians; however, the views of frontline ICU staff on such technology are unknown. To identify clinician perspectives on the current state of communication among patients, families, and clinicians in the ICU, and assess their views on whether and how an electronic portal may address existing communication deficits and improve care. Three focus groups comprised altogether of 26 clinicians from 6 ICUs, representing several disciplines in an academic medical center in Boston, Massachusetts. Transcripts were analyzed inductively for major themes using grounded theory. We identified seven themes reflecting clinician perspectives on communication challenges and desired portal functionality: (1) comprehension and literacy; (2) results and updates; (3) patient and family preferences; (4) interclinician communication; (5) family informational needs; (6) the ICU as an unfamiliar environment; and (7) enhancing humanism through technology. Each theme included current gaps in practice, potential benefits and concerns related to an ICU communication portal, and participant recommendations. Benefits included enhanced education, patient/family engagement, and clinician workflow. Challenges included the stress and uncertainty of ICU care, fear of technology replacing human connection, existing interclinician communication failures, and the tension between informing families without overwhelming them. Overall, clinicians were cautiously supportive of an electronic portal to enhance communication in the ICU and made several specific recommendations for design and implementation. As new technologies expand opportunities for greater transparency and participation in

  11. Automated detection of a prostate Ni-Ti stent in electronic portal images.

    Science.gov (United States)

    Carl, Jesper; Nielsen, Henning; Nielsen, Jane; Lund, Bente; Larsen, Erik Hoejkjaer

    2006-12-01

    Planning target volumes (PTV) in fractionated radiotherapy still have to be outlined with wide margins to the clinical target volume due to uncertainties arising from daily shift of the prostate position. A recently proposed new method of visualization of the prostate is based on insertion of a thermo-expandable Ni-Ti stent. The current study proposes a new detection algorithm for automated detection of the Ni-Ti stent in electronic portal images. The algorithm is based on the Ni-Ti stent having a cylindrical shape with a fixed diameter, which was used as the basis for an automated detection algorithm. The automated method uses enhancement of lines combined with a grayscale morphology operation that looks for enhanced pixels separated with a distance similar to the diameter of the stent. The images in this study are all from prostate cancer patients treated with radiotherapy in a previous study. Images of a stent inserted in a humanoid phantom demonstrated a localization accuracy of 0.4-0.7 mm which equals the pixel size in the image. The automated detection of the stent was compared to manual detection in 71 pairs of orthogonal images taken in nine patients. The algorithm was successful in 67 of 71 pairs of images. The method is fast, has a high success rate, good accuracy, and has a potential for unsupervised localization of the prostate before radiotherapy, which would enable automated repositioning before treatment and allow for the use of very tight PTV margins.

  12. Automated detection of a prostate Ni-Ti stent in electronic portal images

    International Nuclear Information System (INIS)

    Carl, Jesper; Nielsen, Henning; Nielsen, Jane; Lund, Bente; Larsen, Erik Hoejkjaer

    2006-01-01

    Planning target volumes (PTV) in fractionated radiotherapy still have to be outlined with wide margins to the clinical target volume due to uncertainties arising from daily shift of the prostate position. A recently proposed new method of visualization of the prostate is based on insertion of a thermo-expandable Ni-Ti stent. The current study proposes a new detection algorithm for automated detection of the Ni-Ti stent in electronic portal images. The algorithm is based on the Ni-Ti stent having a cylindrical shape with a fixed diameter, which was used as the basis for an automated detection algorithm. The automated method uses enhancement of lines combined with a grayscale morphology operation that looks for enhanced pixels separated with a distance similar to the diameter of the stent. The images in this study are all from prostate cancer patients treated with radiotherapy in a previous study. Images of a stent inserted in a humanoid phantom demonstrated a localization accuracy of 0.4-0.7 mm which equals the pixel size in the image. The automated detection of the stent was compared to manual detection in 71 pairs of orthogonal images taken in nine patients. The algorithm was successful in 67 of 71 pairs of images. The method is fast, has a high success rate, good accuracy, and has a potential for unsupervised localization of the prostate before radiotherapy, which would enable automated repositioning before treatment and allow for the use of very tight PTV margins

  13. Estimation of four-dimensional dose distribution using electronic portal imaging device in radiation therapy

    International Nuclear Information System (INIS)

    Mizoguchi, Asumi; Arimura, Hidetaka; Shioyama, Yoshiyuki

    2013-01-01

    We are developing a method to evaluate four-dimensional radiation dose distribution in a patient body based upon the animated image of EPID (electronic portal imaging device) which is an image of beam-direction at the irradiation. In the first place, we have obtained the image of the dose which is emitted from patient body at therapy planning using therapy planning CT image and dose evaluation algorism. In the second place, we have estimated the emission dose image at the irradiation using EPID animated image which is obtained at the irradiation. In the third place, we have got an affine transformation matrix including respiratory movement in the body by performing linear registration on the emission dose image at therapy planning to get the one at the irradiation. In the fourth place, we have applied the affine transformation matrix on the therapy planning CT image and estimated the CT image 'at irradiation'. Finally we have evaluated four-dimensional dose distribution by calculating dose distribution in the CT image 'at irradiation' which has been estimated for each frame of the EPID animated-image. This scheme may be useful for evaluating therapy results and risk management. (author)

  14. Assessment of a customised immobilisation system for head and neck IMRT using electronic portal imaging

    International Nuclear Information System (INIS)

    Humphreys, Mandy; Guerrero Urbano, M.Teressa; Mubata, Cefas; Miles, Elizabeth; Harrington, Kevin J.; Bidmead, Margaret; Nutting, Christopher M.

    2005-01-01

    Purpose: To evaluate set-up reproducibility of a cabulite shell and determine CTV-PTV margins for head and neck intensity-modulated-radiotherapy. Materials and methods: Twenty patients were entered into the study. A total of 354 anterior and lateral isocentric electronic portal images (EPIs) were compared to simulator reference images. Results: About 94% of all translational displacements were ≤3 mm, and 99% ≤5 mm. The overall systematic error was 0.9 mm (±1.0SD) in the Right-Left, 0.7 mm (±0.9SD) in the Superior-Inferior and -0.02 mm (±1.1SD) in the Anterior-Posterior directions. The corresponding SDs of the random errors were ±0.4, ±0.6 and ±0.7 mm. The estimated margins required from CTV-PTV were calculated according to the Van Herk formula was 2.9, 2.6 and 3.3 mm, respectively. Conclusions: This head and neck immobilisation system is of sufficient accuracy for its use with IMRT treatments and a 3 mm CTV-PTV margin has been adopted

  15. Development of a daily dosimetric control for radiation therapy using an electronic portal imaging device (EPID)

    International Nuclear Information System (INIS)

    Saboori, Mohammadsaeed

    2015-01-01

    Electronic Portal Imaging Devices (EPIDs) can be used to perform dose measurements during radiation therapy treatments if dedicated calibration and correction procedures are applied. The purpose of this study was to provide a new calibration and correction model for an amorphous silicon (a-Si) EPID for use in transit dose verification of step-and-shoot intensity modulated radiation therapy (IMRT). A model was created in a commercial treatment planning system to calculate the nominal two-dimensional (2D) dose map of each radiation field at the EPID level. The EPID system was calibrated and correction factors were determined using a reference set-up, which consisted a patient phantom and an EPID phantom. The advantage of this method is that for the calibration, the actual beam spectrum is used to mimic a patient measurement. As proof-of-principle, the method was tested for the verification of two 7-field IMRT treatment plans with tumor sites in the head-and-neck and pelvic region. Predicted and measured EPID responses were successfully compared to the nominal data from treatment planning using dose difference maps and gamma analyses. Based on our result it can be concluded that this new method of 2D EPID dosimetry is a potential tool for simple patient treatment fraction dose verification.

  16. Verification of patient position and delivery of IMRT by electronic portal imaging

    International Nuclear Information System (INIS)

    Fielding, Andrew L.; Evans, Philip M.; Clark, Catharine H.

    2004-01-01

    Background and purpose: The purpose of the work presented in this paper was to determine whether patient positioning and delivery errors could be detected using electronic portal images of intensity modulated radiotherapy (IMRT). Patients and methods: We carried out a series of controlled experiments delivering an IMRT beam to a humanoid phantom using both the dynamic and multiple static field method of delivery. The beams were imaged, the images calibrated to remove the IMRT fluence variation and then compared with calibrated images of the reference beams without any delivery or position errors. The first set of experiments involved translating the position of the phantom both laterally and in a superior/inferior direction a distance of 1, 2, 5 and 10 mm. The phantom was also rotated 1 and 2 deg. For the second set of measurements the phantom position was kept fixed and delivery errors were introduced to the beam. The delivery errors took the form of leaf position and segment intensity errors. Results: The method was able to detect shifts in the phantom position of 1 mm, leaf position errors of 2 mm, and dosimetry errors of 10% on a single segment of a 15 segment IMRT step and shoot delivery (significantly less than 1% of the total dose). Conclusions: The results of this work have shown that the method of imaging the IMRT beam and calibrating the images to remove the intensity modulations could be a useful tool in verifying both the patient position and the delivery of the beam

  17. Development and clinical implementation of an enhanced display algorithm for use in networked electronic portal imaging

    International Nuclear Information System (INIS)

    Heuvel, Frank van den; Han, Ihn; Chungbin, Suzanne; Strowbridge, Amy; Tekyi-Mensah, Sam; Ragan, Don P.

    1999-01-01

    Purpose: To introduce and clinically validate a preprocessing algorithm that allows clinical images from an electronic portal imaging device (EPID) to be displayed on any computer monitor, without loss of clinical usability. The introduction of such a system frees EPI systems from the constraints of fixed viewing workstations and increases mobility of the images in a department. Methods and Materials: The preprocessing algorithm, together with its variable parameters is introduced. Clinically, the algorithm is tested using an observer study of 316 EPID images of the pelvic region in the framework of treatment of carcinoma of the cervix and endometrium. Both anterior-posterior (AP/PA) and latero-lateral (LAT) images were used. The images scored were taken from six different patients, five of whom were obese, female, and postmenopausal. The result is tentatively compared with results from other groups. The scoring system, based on the number of visible landmarks in the port, is proposed and validated. Validation was performed by having the observer panel score images with artificially induced noise levels. A comparative study was undertaken with a standard automatic window and leveling display technique. Finally, some case studies using different image sites and EPI detectors are presented. Results: The image quality for all images in this study was deemed to be clinically useful (mean score > 1). Most of the images received a score which was second highest (AP/PA landmarks ≥ 6 and LAT landmarks ≥ 5). Obesity, which has been an important factor determining the image quality, was not seen to be a factor here. Compared to standard techniques a highly significant improvement was determined with regard to clinical usefulness. The algorithm performs fast (less than 9 seconds) and needs no additional user interaction in most of the cases. The algorithm works well on both direct detection portal imagers and camera-based imagers whether analog or digital cameras

  18. Walter Reed Army Medical Center's Internet-based electronic health portal.

    Science.gov (United States)

    Abbott, Kevin C; Boocks, Carl E; Sun, Zhengyi; Boal, Thomas R; Poropatich, Ronald K

    2003-12-01

    Use of the World Wide Web (WWW) and electronic media to facilitate medical care has been the subject of many reports in the popular press. However, few reports have documented the results of implementing electronic health portals for essential medical tasks, such as prescription refills and appointments. At Walter Reed Army Medical Center, "Search & Learn" medical information, Internet-based prescription refills and patient appointments were established in January 2001. A multiphase retrospective analysis was conducted to determine the use of the "Search & Learn" medical information and the relative number of prescription refills and appointments conducted via the WWW compared with conventional methods. From January 2001 to May 2002, there were 34,741 refills and 819 appointments made over the Internet compared with 2,275,112 refills and approximately 500,000 appointments made conventionally. WWW activity accounted for 1.52% of refills and 0.16% of appointments. There was a steady increase in this percentage over the time of the analysis. In April of 2002, the monthly average of online refills had risen to 4.57% and online appointments were at 0.27%. Online refills were projected to account for 10% of all prescriptions in 2 years. The "Search & Learn" medical information portion of our web site received 147,429 unique visits during this same time frame, which was an average of 326 visitors per day. WWW-based methods of conducting essential medical tasks accounted for a small but rapidly increasing percentage of total activity at Walter Reed Army Medical Center. Subsequent phases of analysis will assess demographic and geographic factors and aid in the design of future systems to increase use of the Internet-based systems.

  19. CAN MARKETING SUPPORT THE IMPLEMENTATION OF EFFECTIVE EGOVERNMENT? ANALYSIS OF THE SINGLE POINT OF ACCESS PORTAL FOR ROMANIAN ELECTRONIC PUBLIC SERVICES

    Directory of Open Access Journals (Sweden)

    Velicu Bogdan Calin

    2011-12-01

    Full Text Available The advances in technology hold great potential for helping Romanian government respond to its challenges namely, better service delivery, better procurement, efficient working and better communication with citizens and businesses. While the European Commission develops the main strategies on eGovernment, every member state has the freedom to identify its own necessities and decide according to specific social, administrative and economic context. Designing, cost setting, choosing the best supply channels or communicating with involved actors, are all marketing instruments which, if used accordingly, can ensure modern and efficient public services. This paper presents an analysis of the degree of development of public services available at the www.e-guvernare.ro portal, the single point of access for specific Romanian electronic public services.

  20. Dosimetric verification of radiation therapy including intensity modulated treatments, using an amorphous-silicon electronic portal imaging device

    Science.gov (United States)

    Chytyk-Praznik, Krista Joy

    Radiation therapy is continuously increasing in complexity due to technological innovation in delivery techniques, necessitating thorough dosimetric verification. Comparing accurately predicted portal dose images to measured images obtained during patient treatment can determine if a particular treatment was delivered correctly. The goal of this thesis was to create a method to predict portal dose images that was versatile and accurate enough to use in a clinical setting. All measured images in this work were obtained with an amorphous silicon electronic portal imaging device (a-Si EPID), but the technique is applicable to any planar imager. A detailed, physics-motivated fluence model was developed to characterize fluence exiting the linear accelerator head. The model was further refined using results from Monte Carlo simulations and schematics of the linear accelerator. The fluence incident on the EPID was converted to a portal dose image through a superposition of Monte Carlo-generated, monoenergetic dose kernels specific to the a-Si EPID. Predictions of clinical IMRT fields with no patient present agreed with measured portal dose images within 3% and 3 mm. The dose kernels were applied ignoring the geometrically divergent nature of incident fluence on the EPID. A computational investigation into this parallel dose kernel assumption determined its validity under clinically relevant situations. Introducing a patient or phantom into the beam required the portal image prediction algorithm to account for patient scatter and attenuation. Primary fluence was calculated by attenuating raylines cast through the patient CT dataset, while scatter fluence was determined through the superposition of pre-calculated scatter fluence kernels. Total dose in the EPID was calculated by convolving the total predicted incident fluence with the EPID-specific dose kernels. The algorithm was tested on water slabs with square fields, agreeing with measurement within 3% and 3 mm. The

  1. An efficient genetic algorithm for the design optimization of cold-formed steel portal frame buildings

    OpenAIRE

    Phan, Thanh Duoc; Lim, James; Tanyimboh, Tiku T.; Sha, Wei

    2013-01-01

    The design optimization of a cold-formed steel portal frame building is considered in this paper. The proposed genetic algorithm (GA) optimizer considers both topology (i.e., frame spacing and pitch) and cross-sectional sizes of the main structural members as the decision variables. Previous GAs in the literature were characterized by poor convergence, including slow progress, that usually results in excessive computation times and/or frequent failure to achieve an optimal or near-optimal sol...

  2. Verification of multileaf collimator leaf positions using an electronic portal imaging device

    International Nuclear Information System (INIS)

    Samant, Sanjiv S.; Zheng Wei; Parra, Nestor Andres; Chandler, Jason; Gopal, Arun; Wu Jian; Jain Jinesh; Zhu Yunping; Sontag, Marc

    2002-01-01

    An automated method is presented for determining individual leaf positions of the Siemens dual focus multileaf collimator (MLC) using the Siemens BEAMVIEW(PLUS) electronic portal imaging device (EPID). Leaf positions are computed with an error of 0.6 mm at one standard deviation (σ) using separate computations of pixel dimensions, image distortion, and radiation center. The pixel dimensions are calculated by superimposing the film image of a graticule with the corresponding EPID image. A spatial correction is used to compensate for the optical distortions of the EPID, reducing the mean distortion from 3.5 pixels (uncorrected) per localized x-ray marker to 2 pixels (1 mm) for a rigid rotation and 1 pixel for a third degree polynomial warp. A correction for a nonuniform dosimetric response across the field of view of the EPID images is not necessary due to the sharp intensity gradients across leaf edges. The radiation center, calculated from the average of the geometric centers of a square field at 0 deg. and 180 deg. collimator angles, is independent of graticule placement error. Its measured location on the EPID image was stable to within 1 pixel based on 3 weeks of repeated extensions/retractions of the EPID. The MLC leaf positions determined from the EPID images agreed to within a pixel of the corresponding values measured using film and ionization chamber. Several edge detection algorithms were tested: contour, Sobel, Roberts, Prewitt, Laplace, morphological, and Canny. These agreed with each other to within ≤1.2 pixels for the in-air EPID images. Using a test pattern, individual MLC leaves were found to be typically within 1 mm of the corresponding record-and-verify values, with a maximum difference of 1.8 mm, and standard deviations of <0.3 mm in the daily reproducibility. This method presents a fast, automatic, and accurate alternative to using film or a light field for the verification and calibration of the MLC

  3. A distortion correction method for image intensifier and electronic portal images used in radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ioannidis, G T; Geramani, K N; Zamboglou, N [Strahlenklinik, Stadtische Kliniken Offenbach, Offenbach (Germany); Uzunoglu, N [Department of Electrical and Computer Engineering, National Technical University of Athens, Athens (Greece)

    1999-12-31

    At the most of radiation departments a simulator and an `on line` verification system of the treated volume, in form of an electronic portal imaging device (EPID), are available. Networking and digital handling (saving, archiving etc.) of the image information is a necessity in the image processing procedures in order to evaluate verification and simulation recordings at the computer screen. Distortion is on the other hand prerequisite for quantitative comparison of both image modalities. Another limitation factor, in order to make quantitative assertions, is the fact that the irradiation fields in radiotherapy are usually bigger than the field of view of an image intensifier. Several segments of the irradiation field must therefore be acquired. Using pattern recognition techniques these segments can be composed into a single image. In this paper a distortion correction method will be presented. The method is based upon a well defined Grid which is embedded during the registration process on the image. The video signal from the image intensifier is acquired and processed. The grid is then recognised using image processing techniques. Ideally if all grid points are recognised, various methods can be applied in order to correct the distortion. But in practice this is not the case. Overlapping structures (bones etc.) have as a consequence that not all of the grid points can be recognised. Mathematical models from the Graph theory are applied in order to reconstruct the whole grid. The deviation of the grid points positions from the rated value is then used to calculate correction coefficients. This method (well defined grid, grid recognition, correction factors) can also be applied in verification images from the EPID or in other image modalities, and therefore a quantitative comparison in radiation treatment is possible. The distortion correction method and the application on simulator images will be presented. (authors)

  4. Transmission dosimetry with a liquid-filled electronic portal imaging device

    International Nuclear Information System (INIS)

    Boellaard, R.; Van Herk, M.; Mijnheer, B.J.

    1995-01-01

    The aim of transmission dosimetry is to correlate transmission dose values with patient dose values. A liquid-filled electronic portal imaging device (EPID) has been developed. After determination of the dose response relationship, i.e. the relation between pixel value and dose rate, for clinical situations it was found that the EPID is applicable for two-dimensional dosimetry with an accuracy of about 1%. The aim of this study was to investigate transmission dose distributions at different phantom-detector distances to predict exit dose distributions from transmission dose images. An extensive set of transmission dose measurements below homogeneous phantoms were performed with the EPID. The influence of several parameters such as field size, phantom thickness, phantom-detector distance and phantom-source distance on the transmission dose and its distribution were investigated. The two-dimensional transmission dose images were separated into two components: a primary dose and a scattered dose distribution. It was found that the scattered dose is maximal at a phantom thickness of about 10 cm. The scattered dose distribution below a homogeneous phantom has a Gaussian shape. The width of the Gaussian is small at small phantom-detector distances and increases for larger phantom-detector distances. The dependence of the scattered dose distribution on the field size at various phantom-detector distances has been used to estimate the dose distribution at the exit site of the phantom. More work is underway to determine the exit dose distributions for clinical situations, including the presence of inhomogeneities

  5. Transmission dosimetry with a liquid-filled electronic portal imaging device

    Energy Technology Data Exchange (ETDEWEB)

    Boellaard, R; Van Herk, M; Mijnheer, B J [Nederlands Kanker Inst. ` Antoni van Leeuwenhoekhuis` , Amsterdam (Netherlands)

    1995-12-01

    The aim of transmission dosimetry is to correlate transmission dose values with patient dose values. A liquid-filled electronic portal imaging device (EPID) has been developed. After determination of the dose response relationship, i.e. the relation between pixel value and dose rate, for clinical situations it was found that the EPID is applicable for two-dimensional dosimetry with an accuracy of about 1%. The aim of this study was to investigate transmission dose distributions at different phantom-detector distances to predict exit dose distributions from transmission dose images. An extensive set of transmission dose measurements below homogeneous phantoms were performed with the EPID. The influence of several parameters such as field size, phantom thickness, phantom-detector distance and phantom-source distance on the transmission dose and its distribution were investigated. The two-dimensional transmission dose images were separated into two components: a primary dose and a scattered dose distribution. It was found that the scattered dose is maximal at a phantom thickness of about 10 cm. The scattered dose distribution below a homogeneous phantom has a Gaussian shape. The width of the Gaussian is small at small phantom-detector distances and increases for larger phantom-detector distances. The dependence of the scattered dose distribution on the field size at various phantom-detector distances has been used to estimate the dose distribution at the exit site of the phantom. More work is underway to determine the exit dose distributions for clinical situations, including the presence of inhomogeneities.

  6. Electronic portal image assisted reduction of systematic set-up errors in head and neck irradiation

    International Nuclear Information System (INIS)

    Boer, Hans C.J. de; Soernsen de Koste, John R. van; Creutzberg, Carien L.; Visser, Andries G.; Levendag, Peter C.; Heijmen, Ben J.M.

    2001-01-01

    Purpose: To quantify systematic and random patient set-up errors in head and neck irradiation and to investigate the impact of an off-line correction protocol on the systematic errors. Material and methods: Electronic portal images were obtained for 31 patients treated for primary supra-glottic larynx carcinoma who were immobilised using a polyvinyl chloride cast. The observed patient set-up errors were input to the shrinking action level (SAL) off-line decision protocol and appropriate set-up corrections were applied. To assess the impact of the protocol, the positioning accuracy without application of set-up corrections was reconstructed. Results: The set-up errors obtained without set-up corrections (1 standard deviation (SD)=1.5-2 mm for random and systematic errors) were comparable to those reported in other studies on similar fixation devices. On an average, six fractions per patient were imaged and the set-up of half the patients was changed due to the decision protocol. Most changes were detected during weekly check measurements, not during the first days of treatment. The application of the SAL protocol reduced the width of the distribution of systematic errors to 1 mm (1 SD), as expected from simulations. A retrospective analysis showed that this accuracy should be attainable with only two measurements per patient using a different off-line correction protocol, which does not apply action levels. Conclusions: Off-line verification protocols can be particularly effective in head and neck patients due to the smallness of the random set-up errors. The excellent set-up reproducibility that can be achieved with such protocols enables accurate dose delivery in conformal treatments

  7. Transabdominal ultrasonography, computed tomography and electronic portal imaging for 3-dimensional conformal radiotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Jereczek-Fossa, B.A.; Orecchia, R.; Cattani, F.; Garibaldi, C.; Cambria, R.; Valenti, M.; Ciocca, M.; Zerini, D.; Boboc, G.I.; Vavassori, A.; Ivaldi, G.B.; Kowalczyk, A.; Matei, D.V.; Cobelli, O. de

    2007-01-01

    Purpose: To evaluate the feasibility and accuracy of daily B-mode acquisition and targeting ultrasound-based prostate localization (BAT trademark) and to compare it with computed tomography (CT) and electronic portal imaging (EPI) in 3-dimensional conformal radiotherapy (3-D CRT) for prostate cancer. Patients and Methods: Ten patients were treated with 3-D CRT (72 Gy/30 fractions, 2.4 Gy/fraction, equivalent to 80 Gy/40 fractions, for α/β ratio of 1.5 Gy) and daily BAT-based prostate localization. For the first 5 fractions, CT and EPI were also performed in order to compare organ-motion and set-up error, respectively. Results: 287 BAT-, 50 CT- and 46 EPI-alignments were performed. The average BAT-determined misalignments in latero-lateral, antero-posterior and cranio-caudal directions were -0.9 mm ± 3.3 mm, 1.0 mm ± 4.0 mm and -0.9 mm ± 3.8 mm, respectively. The differences between BAT- and CT-determined organ-motion in latero-lateral, antero-posterior and cranio-caudal directions were 2.7 mm ± 1.9 mm, 3.9 ± 2.8 mm and 3.4 ± 3.0 mm, respectively. Weak correlation was found between BAT- and CT-determined misalignments in antero-posterior direction, while no correlation was observed in latero-lateral and cranio-caudal directions. The correlation was more significant when only data of good image-quality patients were analyzed (8 patients). Conclusion: BAT ensures the relative positions of target are the same during treatment and in treatment plan, however, the reliability of alignment is patient-dependent. The average BAT-determined misalignments were small, confirming the prevalence of random errors in 3-D CRT. Further study is warranted in order to establish the clinical value of BAT. (orig.)

  8. A Monte Carlo calculation model of electronic portal imaging device for transit dosimetry through heterogeneous media

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jihyung; Jung, Jae Won, E-mail: jungj@ecu.edu [Department of Physics, East Carolina University, Greenville, North Carolina 27858 (United States); Kim, Jong Oh [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15232 (United States); Yeo, Inhwan [Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, California 92354 (United States)

    2016-05-15

    Purpose: To develop and evaluate a fast Monte Carlo (MC) dose calculation model of electronic portal imaging device (EPID) based on its effective atomic number modeling in the XVMC code. Methods: A previously developed EPID model, based on the XVMC code by density scaling of EPID structures, was modified by additionally considering effective atomic number (Z{sub eff}) of each structure and adopting a phase space file from the EGSnrc code. The model was tested under various homogeneous and heterogeneous phantoms and field sizes by comparing the calculations in the model with measurements in EPID. In order to better evaluate the model, the performance of the XVMC code was separately tested by comparing calculated dose to water with ion chamber (IC) array measurement in the plane of EPID. Results: In the EPID plane, calculated dose to water by the code showed agreement with IC measurements within 1.8%. The difference was averaged across the in-field regions of the acquired profiles for all field sizes and phantoms. The maximum point difference was 2.8%, affected by proximity of the maximum points to penumbra and MC noise. The EPID model showed agreement with measured EPID images within 1.3%. The maximum point difference was 1.9%. The difference dropped from the higher value of the code by employing the calibration that is dependent on field sizes and thicknesses for the conversion of calculated images to measured images. Thanks to the Z{sub eff} correction, the EPID model showed a linear trend of the calibration factors unlike those of the density-only-scaled model. The phase space file from the EGSnrc code sharpened penumbra profiles significantly, improving agreement of calculated profiles with measured profiles. Conclusions: Demonstrating high accuracy, the EPID model with the associated calibration system may be used for in vivo dosimetry of radiation therapy. Through this study, a MC model of EPID has been developed, and their performance has been rigorously

  9. Initial Clinical Experience Performing Patient Treatment Verification With an Electronic Portal Imaging Device Transit Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Berry, Sean L., E-mail: BerryS@MSKCC.org [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York (United States); Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Polvorosa, Cynthia; Cheng, Simon; Deutsch, Israel; Chao, K. S. Clifford; Wuu, Cheng-Shie [Department of Radiation Oncology, Columbia University, New York, New York (United States)

    2014-01-01

    Purpose: To prospectively evaluate a 2-dimensional transit dosimetry algorithm's performance on a patient population and to analyze the issues that would arise in a widespread clinical adoption of transit electronic portal imaging device (EPID) dosimetry. Methods and Materials: Eleven patients were enrolled on the protocol; 9 completed and were analyzed. Pretreatment intensity modulated radiation therapy (IMRT) patient-specific quality assurance was performed using a stringent local 3%, 3-mm γ criterion to verify that the planned fluence had been appropriately transferred to and delivered by the linear accelerator. Transit dosimetric EPID images were then acquired during treatment and compared offline with predicted transit images using a global 5%, 3-mm γ criterion. Results: There were 288 transit images analyzed. The overall γ pass rate was 89.1% ± 9.8% (average ± 1 SD). For the subset of images for which the linear accelerator couch did not interfere with the measurement, the γ pass rate was 95.7% ± 2.4%. A case study is presented in which the transit dosimetry algorithm was able to identify that a lung patient's bilateral pleural effusion had resolved in the time between the planning CT scan and the treatment. Conclusions: The EPID transit dosimetry algorithm under consideration, previously described and verified in a phantom study, is feasible for use in treatment delivery verification for real patients. Two-dimensional EPID transit dosimetry can play an important role in indicating when a treatment delivery is inconsistent with the original plan.

  10. Towards the development of a comprehensive model of an electronic portal imaging device using Geant4

    International Nuclear Information System (INIS)

    Blake, S.; Kuncic, Z.; Vial, P.; Holloway, L.

    2010-01-01

    Full text: This work represents the first stage of an ongoing study to investigate the physical processes occurring within electronic portal imaging devices (EPlDs), including the effects of optical scattering on image quality and dosimetry. The objective of this work was to develop an initial Monte Carlo model of a linear accelerator (Iinac) beam and an EPID. The ability to simulate the radiation transport of both high energy and optical photons in a single Monte Carlo model was tested. Data from the Phase-space database for external beam radiotherapy (International Atomic Energy Agency, IAEA) was used with the Geant4 toolkit to construct a model of a Siemens Primus linac 6 MY photon source. Dose profiles and percent depth dose (PDD) curves were extracted from simulations of dose in water and compared to experimental measurements. A preliminary EPID model was developed to incorporate both high energy radiation and optical photon transport. Agreement in dose profiles inside the open beam was within 1.6%. Mean agreement in PDD curves beyond depth of dose maximum was within 6.1 % (local percent difference). The radiation transport of both high energy and optical photons were simulated and visualized in the EPID model. Further work is required to experimentally validate the EPID model. The comparison of simulated dose in water with measurements indicates that the IAEA phase-space may represent an accurate model of a linac source. We have demonstrated the feasibility of developing a comprehensive EPID model incorporating both high energy and optical physics in Geant4. (author)

  11. The use of an electronic portal imaging device for exit dosimetry and quality control measurements

    International Nuclear Information System (INIS)

    Kirby, Michael C.; Williams, Peter C.

    1995-01-01

    Purpose: To determine ways in which electronic portal imaging devices (EPIDs) could be used to (a) measure exit doses for external beam radiotherapy and (b) perform quality control checks on linear accelerators. Methods and Materials: When imaging, our fluoroscopic EPID adjusts the gain, offset, and frame acquisition time of the charge coupled device (CCD) camera automatically, to allow for the range of photon transmissions through the patient, and to optimize the signal-to-noise ratio. However, our EPID can be programmed to act as an integrating dosemeter. EPID dosemeter measurements were made for 20 MV photons, for different field sizes and thicknesses of unit density phantom material placed at varying exit surface to detector distances. These were compared with simultaneous Silicon diode exit dose measurements. Our exit dosimetry technique was verified using an anthropomorphic type phantom, and some initial measurements have been made for patients treated with irregularly shaped 20 MV x-ray fields. In this dosimetry mode, our EPID was also used to measure certain quality control parameters, x-ray field flatness, and the verification of segmented intensity modulated field prescriptions. Results: Configured for dosimetry, our EPID exhibited a highly linear response, capable of resolving individual monitor units. Exit doses could be measured to within about 3% of that measured using Silicon diodes. Field flatness was determined to within 1.5% of Farmer dosemeter measurements. Segmented intensity modulated fields can be easily verified. Conclusions: Our EPID has the versatility to assess a range of parameters pertinent to the delivery of high quality, high precision radiotherapy. When configured appropriately, it can measure exit doses in vivo, with reasonable accuracy, perform certain quick quality control checks, and analyze segmented intensity modulated treatment fields

  12. Detection of organ movement in cervix cancer patients using a fluoroscopic electronic portal imaging device and radiopaque markers

    International Nuclear Information System (INIS)

    Kaatee, Robert S.J.P.; Olofsen, Manouk J.J.; Verstraate, Marjolein B.J.; Quint, Sandra; Heijmen, Ben J.M.

    2002-01-01

    Purpose: To investigate the use of a fluoroscopic electronic portal imaging device (EPID) and radiopaque markers to detect internal cervix movement. Methods and Materials: For 10 patients with radiopaque markers clamped to the cervix, electronic portal images were made during external beam irradiation. Bony structures and markers in the portal images were registered with the same structures in the corresponding digitally reconstructed radiographs of the planning computed tomogram. Results: The visibility of the markers in the portal images was good, but their fixation should be improved. Generally, the correlation between bony structure displacements and marker movement was poor, the latter being substantially larger. The standard deviations describing the systematic and random bony anatomy displacements were 1.2 and 2.6 mm, 1.7 and 2.9 mm, and 1.6 and 2.7 mm in the lateral, cranial-caudal, and dorsal-ventral directions, respectively. For the marker movement those values were 3.4 and 3.4 mm, 4.3 and 5.2 mm, 3.2 and 5.2 mm, respectively. Estimated clinical target volume to planning target volume (CTV-PTV) planning margins (∼11 mm) based on the observed overall marker displacements (bony anatomy + internal cervix movement) are only marginally larger than the margins required to account for internal marker movement alone. Conclusions: With our current patient setup techniques and methods of setup verification and correction, the required CTV-PTV margins are almost fully determined by internal organ motion. Setup verification and correction using radiopaque markers might allow decreasing those margins, but technical improvements are needed

  13. Geo-portal as a planning instrument: supporting decision making and fostering market potential of Energy efficiency in buildings

    Science.gov (United States)

    Cuca, Branka; Brumana, Raffaella; Oreni, Daniela; Iannaccone, Giuliana; Sesana, Marta Maria

    2014-03-01

    Steady technological progress has led to a noticeable advancement in disciplines associated with Earth observation. This has enabled information transition regarding changing scenarios, both natural and urban, to occur in (almost) real time. In particular, the need for integration on a local scale with the wider territorial framework has occurred in analysis and monitoring of built environments over the last few decades. The progress of Geographic Information (GI) science has provided significant advancements when it comes to spatial analysis, while the almost free availability of the internet has ensured a fast and constant exchange of geo-information, even for everyday users' requirements. Due to its descriptive and semantic nature, geo-spatial information is capable of providing a complete overview of a certain phenomenon and of predicting the implications within the natural, social and economic context. However, in order to integrate geospatial data into decision making processes, it is necessary to provide a specific context, which is well supported by verified data. This paper investigates the potentials of geo-portals as planning instruments developed to share multi-temporal/multi-scale spatial data, responding to specific end-users' demands in the case of Energy efficiency in Buildings (EeB) across European countries. The case study regards the GeoCluster geo-portal and mapping tool (Project GE2O, FP7), built upon a GeoClustering methodology for mapping of indicators relevant for energy efficiency technologies in the construction sector.

  14. Efficiency of herbal medicine Dai-kenchu-to on portal blood flow in rat models

    OpenAIRE

    Muraoka, Izumi; Takatsuki, Mitsuhisa; Soyama, Akihiko; Yamaguchi, Izumi; Tanaka, Shiro; Tanaka, Takayuki; Kinoshita, Ayaka; Hara, Takanobu; Kuroki, Tamotsu; Eguchi, Susumu

    2015-01-01

    Introduction: To clarify the influence of Dai-Kenchu-To (DKT) on portal blood flow (PBF), PBF was continuously measured with Doppler ultrasound. Methods: Normal liver rats were divided into a DKT 90 mg/kg, DKT 270 mg/kg administered group, and control, while cirrhotic liver rats were divided into a DKT-LC 90 mg/kg administered group and Control-LC. The PBF was measured after the administration of either DKT or water for 60 min by laser Doppler flowmetry system. Results: The PBF in the D...

  15. Verifying 4D gated radiotherapy using time-integrated electronic portal imaging: a phantom and clinical study

    Directory of Open Access Journals (Sweden)

    Slotman Ben J

    2007-08-01

    Full Text Available Abstract Background Respiration-gated radiotherapy (RGRT can decrease treatment toxicity by allowing for smaller treatment volumes for mobile tumors. RGRT is commonly performed using external surrogates of tumor motion. We describe the use of time-integrated electronic portal imaging (TI-EPI to verify the position of internal structures during RGRT delivery Methods TI-EPI portals were generated by continuously collecting exit dose data (aSi500 EPID, Portal vision, Varian Medical Systems when a respiratory motion phantom was irradiated during expiration, inspiration and free breathing phases. RGRT was delivered using the Varian RPM system, and grey value profile plots over a fixed trajectory were used to study object positions. Time-related positional information was derived by subtracting grey values from TI-EPI portals sharing the pixel matrix. TI-EPI portals were also collected in 2 patients undergoing RPM-triggered RGRT for a lung and hepatic tumor (with fiducial markers, and corresponding planning 4-dimensional CT (4DCT scans were analyzed for motion amplitude. Results Integral grey values of phantom TI-EPI portals correlated well with mean object position in all respiratory phases. Cranio-caudal motion of internal structures ranged from 17.5–20.0 mm on planning 4DCT scans. TI-EPI of bronchial images reproduced with a mean value of 5.3 mm (1 SD 3.0 mm located cranial to planned position. Mean hepatic fiducial markers reproduced with 3.2 mm (SD 2.2 mm caudal to planned position. After bony alignment to exclude set-up errors, mean displacement in the two structures was 2.8 mm and 1.4 mm, respectively, and corresponding reproducibility in anatomy improved to 1.6 mm (1 SD. Conclusion TI-EPI appears to be a promising method for verifying delivery of RGRT. The RPM system was a good indirect surrogate of internal anatomy, but use of TI-EPI allowed for a direct link between anatomy and breathing patterns.

  16. Portal Hypertension

    Science.gov (United States)

    ... Overview of Gallbladder Cancer Additional Content Medical News Portal Hypertension By Steven K. Herrine, MD, Professor of Medicine, ... Liver Hepatic Encephalopathy Jaundice in Adults Liver Failure Portal Hypertension Portal hypertension is abnormally high blood pressure in ...

  17. First clinical tests using a liquid-filled electronic portal imaging device and a convolution model for the verification of the midplane dose

    International Nuclear Information System (INIS)

    Boellaard, R.; Herk, M. van; Uiterwaal, H.; Mijnheer, B.

    1998-01-01

    Background and purpose: Recently, algorithms have been developed to derive the patient dose from portal dose measurements using a liquid-filled electronic portal imaging device. These algorithms have already been validated for several phantom geometries irradiated under clinical conditions. It is the aim of the present study to investigate the applicability of a liquid-filled electronic portal imaging device in combination with these algorithms for two-dimensional midplane dose verification in clinical practice. Measurements and methods: Portal dose images were obtained during several patient treatments under routine clinical conditions. Measurements were performed to verify the midplane dose during radiotherapy of larynx cancer with 4 MV beams, breast and lung cancer with 8 MV beams and prostate cancer with both 8 and 18 MV beams. Midplane doses, determined from portal dose measurements and analyzed with our algorithms, were compared with midplane doses calculated with our three-dimensional (3D) treatment planning system (TPS). Results: For the larynx treatment the measured 2D midplane dose agreed within 2.0% with TPS calculations in most parts of the field. Larger differences were found in a small region below the skin due to the absence of electron equilibrium, which is not taken into account in our portal dose analysis. For breast irradiations the measured midplane dose showed a homogeneous distribution in the AP direction in the axial plane, while high dose regions were observed in the cranial and caudal part of the breast. Portal dose measurements and TPS calculations agreed within 2.5% for most of the prostate and lung irradiations. For a few of the prostate and lung treatments larger local differences were found due to differences between the actual patient anatomy and the planning CT data, e.g. as a result of variable gas filling in the rectum and anatomical changes in the lung. Conclusions: Portal dose measurements with a liquid-filled electronic portal

  18. Efficiency of the Fermilab Electron Cooler's Collector

    CERN Document Server

    Prost, L R

    2005-01-01

    The newly installed high-energy Recycler Electron Cooling system (REC) at Fermilab will work at an electron energy of 4.34 MeV and a DC beam current of 0.5 A in an energy recovery scheme. For reliable operation of the system, the relative beam current loss must be maintained to levels < 3.e-5. Experiments have shown that the loss is determined by the performance of the electron beam collector, which must retain secondary electrons generated by the primary beam hitting its walls. As a part of the Electron cooling project, the efficiency of the collector for the REC was optimized, both with dedicated test bench experiments and on two versions of the cooler prototype. We find that to achieve the required relative current loss, an axially-symmetric collector must be immersed in a transverse magnetic field with certain strength and gradient prescriptions. Collector efficiencies in various magnetic field configurations, including without a transverse field on the collector, are presented and discussed

  19. Study on the dose response characteristics of a scanning liquid ion-chamber electronic portal imaging device

    CERN Document Server

    Ma Shao Gang; Song Yi Xin

    2002-01-01

    Objective: To study the dose response characteristics and the influence factors such as gantry angle, field size and acquisition mode on the dosimetric response curves, when using a scanning liquid ion-chamber electronic portal imaging device (EPID) for dose verification. Methods: All experiments were carried out on a Varian 600 C/D accelerator (6 MV X-ray) equipped with a Varian PortalVision sup T sup M MK2 type EPID. To obtain the dose response curve, the relationship between the incident radiation intensity to the detector and the pixel value output from the EPID were established. Firstly, the different dose rates of 6 MV X-rays were obtained by varying SSD. Secondly, three digital portal images were acquired for each dose rate using the EPID and averaged to avoid the influence of the dose rate fluctuations of the accelerator. The pixel values of all images were read using self-designed image analysis software, and and average for a region consisting of 11 x 11 pixels around the center was taken as the res...

  20. Daily organ tracking in intensity-modulated radiotherapy of prostate cancer using an electronic portal imaging device with a dose saving acquisition mode

    International Nuclear Information System (INIS)

    Vetterli, Daniel; Thalmann, Sandrine; Behrensmeier, Frank; Kemmerling, Ludger; Born, Ernst J.; Mini, Roberto; Greiner, Richard H.; Aebersold, Daniel M.

    2006-01-01

    Background and purpose: Daily use of conventional electronic portal imaging devices (EPID) for organ tracking is limited due to the relatively high dose required for high quality image acquisition. We studied the use of a novel dose saving acquisition mode (RadMode) allowing to take images with one monitor unit per image in prostate cancer patients undergoing intensity-modulated radiotherapy (IMRT) and tracking of implanted fiducial gold markers. Patients and methods: Twenty five patients underwent implantation of three fiducial gold markers prior to the planning CT. Before each treatment of a course of 37 fractions, orthogonal localization images from the antero-posterior and from the lateral direction were acquired. Portal images of both the setup procedure and the five IMRT treatment beams were analyzed. Results: On average, four localization images were needed for a correct patient setup, resulting in four monitor units extra dose per fraction. The mean extra dose delivered to the patient was thereby increased by 1.2%. The procedure was precise enough to reduce the mean displacements prior to treatment to ≤0.3 mm. Conclusions: The use of a new dose saving acquisition mode enables to perform daily EPID-based prostate tracking with a cumulative extra dose of below 1 Gy. This concept is efficiently used in IMRT-treated patients, where separation of setup beams from treatment beams is mandatory

  1. Electronic portal imaging device detection of radioopaque markers for the evaluation of prostate position during megavoltage irradiation: a clinical study

    International Nuclear Information System (INIS)

    Vigneault, Eric; Pouliot, Jean; Laverdiere, Jacques; Roy, Jean; Dorion, Marc

    1997-01-01

    Purpose: This study was designed to assess daily prostatic apex motion relative to pelvic bone structures during megavoltage irradiation. Methods and Materials: Radioopaque markers were implanted under ultrasound guidance near the prostatic apex of 11 patients with localized prostatic carcinoma. Patients were subsequently treated with a four field-box technique at a beam energy of 23 MV. During treatment, on-line images were obtained with an electronic portal imaging device (EPID). The marker was easily identified, even on unprocessed images, and the distance between the marker and a bony landmark was measured. Timelapse movies were also reviewed. After the completion of treatment, a transcrectal ultrasound examination was performed in 8 of 11 patients, to verify the position of the marker. Results: We acquired over 900 digital portal images and analyzed posterioanterior and right lateral views. The quality of portal images obtained with megavoltage irradiation was good. It was possible to evaluate pelvic bone structures even without image histogram equalization. Moreover, the radioopaque marker was easily visible on every online portal image. The review of timelapse movies showed important interfraction motion of the marker while bone structures remained stable. We measured the position of the marker for each fraction. Marker displacements up to 1.6 cm were measured between 2 consecutive days of treatment. Important marker motions were predominantly in the posteroanterior and cephalocaudal directions. In eight patients, we verified the position of the marker relative to the prostatic apex with ultrasound at the end of the treatments. The marker remained in the trapezoid zone. Intratreatment images reviewed in two cases showed no change in marker position. Our results, obtained during the treatment courses, indicate similar or larger prostate motions than previously observed in studies that used intertreatment x-ray films and CT images. Marker implantation under

  2. Efficient electronic entanglement concentration assisted by single mobile electrons

    International Nuclear Information System (INIS)

    Sheng Yu-Bo; Zhou Lan

    2013-01-01

    We present an efficient entanglement concentration protocol (ECP) for mobile electrons with charge detection. This protocol is quite different from other ECPs for one can obtain a maximally entangled pair from a pair of less-entangled state and a single mobile electron with a certain probability. With the help of charge detection, it can be repeated to reach a higher success probability. It also does not need to know the coefficient of the original less-entangled states. All these advantages may make this protocol useful in current distributed quantum information processing

  3. Use of an amorphous silicon electronic portal imaging device for multileaf collimator quality control and calibration

    International Nuclear Information System (INIS)

    Baker, S J K; Budgell, G J; MacKay, R I

    2005-01-01

    Multileaf collimator (MLC) calibration and quality control is a time-consuming procedure typically involving the processing, scanning and analysis of films to measure leaf and collimator positions. Faster and more reliable calibration procedures are required for these tasks, especially with the introduction of intensity modulated radiotherapy which requires more frequent checking and finer positional leaf tolerances than previously. A routine quality control (QC) technique to measure MLC leaf bank gain and offset, as well as minor offsets (individual leaf position relative to a reference leaf), using an amorphous silicon electronic portal imaging device (EPID) has been developed. The technique also tests the calibration of the primary and back-up collimators. A detailed comparison between film and EPID measurements has been performed for six linear accelerators (linacs) equipped with MLC and amorphous silicon EPIDs. Measurements of field size from 4 to 24 cm with the EPID were systematically smaller than film measurements over all field sizes by 0.4 mm for leaves/back-up collimators and by 0.2 mm for conventional collimators. This effect is due to the gain calibration correction applied by the EPID, resulting in a 'flattening' of primary beam profiles. Linac dependent systematic differences of up to 0.5 mm in individual leaf/collimator positions were also found between EPID and film measurements due to the difference between the mechanical and radiation axes of rotation. When corrections for these systematic differences were applied, the residual random differences between EPID and film were 0.23 mm and 0.26 mm (1 standard deviation) for field size and individual leaf/back-up collimator position, respectively. Measured gains (over a distance of 220 mm) always agreed within 0.4 mm with a standard deviation of 0.17 mm. Minor offset measurements gave a mean agreement between EPID and film of 0.01 ± 0.10 mm (1 standard deviation) after correction for the tilt of the

  4. A high-speed scintillation-based electronic portal imaging device to quantitatively characterize IMRT delivery.

    Science.gov (United States)

    Ranade, Manisha K; Lynch, Bart D; Li, Jonathan G; Dempsey, James F

    2006-01-01

    We have developed an electronic portal imaging device (EPID) employing a fast scintillator and a high-speed camera. The device is designed to accurately and independently characterize the fluence delivered by a linear accelerator during intensity modulated radiation therapy (IMRT) with either step-and-shoot or dynamic multileaf collimator (MLC) delivery. Our aim is to accurately obtain the beam shape and fluence of all segments delivered during IMRT, in order to study the nature of discrepancies between the plan and the delivered doses. A commercial high-speed camera was combined with a terbium-doped gadolinium-oxy-sulfide (Gd2O2S:Tb) scintillator to form an EPID for the unaliased capture of two-dimensional fluence distributions of each beam in an IMRT delivery. The high speed EPID was synchronized to the accelerator pulse-forming network and gated to capture every possible pulse emitted from the accelerator, with an approximate frame rate of 360 frames-per-second (fps). A 62-segment beam from a head-and-neck IMRT treatment plan requiring 68 s to deliver was recorded with our high speed EPID producing approximately 6 Gbytes of imaging data. The EPID data were compared with the MLC instruction files and the MLC controller log files. The frames were binned to provide a frame rate of 72 fps with a signal-to-noise ratio that was sufficient to resolve leaf positions and segment fluence. The fractional fluence from the log files and EPID data agreed well. An ambiguity in the motion of the MLC during beam on was resolved. The log files reported leaf motions at the end of 33 of the 42 segments, while the EPID observed leaf motions in only 7 of the 42 segments. The static IMRT segment shapes observed by the high speed EPID were in good agreement with the shapes reported in the log files. The leaf motions observed during beam-on for step-and-shoot delivery were not temporally resolved by the log files.

  5. A high-speed scintillation-based electronic portal imaging device to quantitatively characterize IMRT delivery

    International Nuclear Information System (INIS)

    Ranade, Manisha K.; Lynch, Bart D.; Li, Jonathan G.; Dempsey, James F.

    2006-01-01

    We have developed an electronic portal imaging device (EPID) employing a fast scintillator and a high-speed camera. The device is designed to accurately and independently characterize the fluence delivered by a linear accelerator during intensity modulated radiation therapy (IMRT) with either step-and-shoot or dynamic multileaf collimator (MLC) delivery. Our aim is to accurately obtain the beam shape and fluence of all segments delivered during IMRT, in order to study the nature of discrepancies between the plan and the delivered doses. A commercial high-speed camera was combined with a terbium-doped gadolinium-oxy-sulfide (Gd 2 O 2 S:Tb) scintillator to form an EPID for the unaliased capture of two-dimensional fluence distributions of each beam in an IMRT delivery. The high speed EPID was synchronized to the accelerator pulse-forming network and gated to capture every possible pulse emitted from the accelerator, with an approximate frame rate of 360 frames-per-second (fps). A 62-segment beam from a head-and-neck IMRT treatment plan requiring 68 s to deliver was recorded with our high speed EPID producing approximately 6 Gbytes of imaging data. The EPID data were compared with the MLC instruction files and the MLC controller log files. The frames were binned to provide a frame rate of 72 fps with a signal-to-noise ratio that was sufficient to resolve leaf positions and segment fluence. The fractional fluence from the log files and EPID data agreed well. An ambiguity in the motion of the MLC during beam on was resolved. The log files reported leaf motions at the end of 33 of the 42 segments, while the EPID observed leaf motions in only 7 of the 42 segments. The static IMRT segment shapes observed by the high speed EPID were in good agreement with the shapes reported in the log files. The leaf motions observed during beam-on for step-and-shoot delivery were not temporally resolved by the log files

  6. Efficiency of herbal medicine Dai-kenchu-to on portal blood flow in rat models.

    Science.gov (United States)

    Muraoka, Izumi; Takatsuki, Mitsuhisa; Soyama, Akihiko; Yamaguchi, Izumi; Tanaka, Shiro; Tanaka, Takayuki; Kinoshita, Ayaka; Hara, Takanobu; Kuroki, Tamotsu; Eguchi, Susumu

    2015-09-01

    To clarify the influence of Dai-Kenchu-To (DKT) on portal blood flow (PBF), PBF was continuously measured with Doppler ultrasound. Normal liver rats were divided into a DKT 90 mg/kg, DKT 270 mg/kg administered group, and control, while cirrhotic liver rats were divided into a DKT-LC 90 mg/kg administered group and Control-LC. The PBF was measured after the administration of either DKT or water for 60 min by laser Doppler flowmetry system. The PBF in the DKT 90 increased approximately 10 min after DKT was administrated, and elevated levels were maintained for approximately 10 min. A comparison of the increase in PBF by the calculating the area under the curve (AUC) revealed that flow was significantly higher in the DKT 90 compared to either the control or the DKT 270 (p DKT-LC and Control-LC. The AUC, revealed no significant difference between the DKT-LC and Control-LC. DKT induced an increase in PBF in normal livers; however, its effects were insufficient to increase PBF in the cirrhotic livers. No increase in the portal blood flow in the cirrhotic liver rats was probably the result of the cirrhotic liver, which had fibrotic change, and, therefore, may not have had sufficient compliance to accept the increasing blood flow volume from the intestinal tract. We suggested DKT has the potential to protect the liver by increasing PBF when the liver has either normal or mild to moderate dysfunction.

  7. Clinical Trial Electronic Portals for Expedited Safety Reporting: Recommendations from the Clinical Trials Transformation Initiative Investigational New Drug Safety Advancement Project.

    Science.gov (United States)

    Perez, Raymond P; Finnigan, Shanda; Patel, Krupa; Whitney, Shanell; Forrest, Annemarie

    2016-12-15

    Use of electronic clinical trial portals has increased in recent years to assist with sponsor-investigator communication, safety reporting, and clinical trial management. Electronic portals can help reduce time and costs associated with processing paperwork and add security measures; however, there is a lack of information on clinical trial investigative staff's perceived challenges and benefits of using portals. The Clinical Trials Transformation Initiative (CTTI) sought to (1) identify challenges to investigator receipt and management of investigational new drug (IND) safety reports at oncologic investigative sites and coordinating centers and (2) facilitate adoption of best practices for communicating and managing IND safety reports using electronic portals. CTTI, a public-private partnership to improve the conduct of clinical trials, distributed surveys and conducted interviews in an opinion-gathering effort to record investigator and research staff views on electronic portals in the context of the new safety reporting requirements described in the US Food and Drug Administration's final rule (Code of Federal Regulations Title 21 Section 312). The project focused on receipt, management, and review of safety reports as opposed to the reporting of adverse events. The top challenge investigators and staff identified in using individual sponsor portals was remembering several complex individual passwords to access each site. Also, certain tasks are time-consuming (eg, downloading reports) due to slow sites or difficulties associated with particular operating systems or software. To improve user experiences, respondents suggested that portals function independently of browsers and operating systems, have intuitive interfaces with easy navigation, and incorporate additional features that would allow users to filter, search, and batch safety reports. Results indicate that an ideal system for sharing expedited IND safety information is through a central portal used by

  8. Use of a line-pair resolution phantom for comprehensive quality assurance of electronic portal imaging devices based on fundamental imaging metrics

    International Nuclear Information System (INIS)

    Gopal, Arun; Samant, Sanjiv S.

    2009-01-01

    Image guided radiation therapy solutions based on megavoltage computed tomography (MVCT) involve the extension of electronic portal imaging devices (EPIDs) from their traditional role of weekly localization imaging and planar dose mapping to volumetric imaging for 3D setup and dose verification. To sustain the potential advantages of MVCT, EPIDs are required to provide improved levels of portal image quality. Therefore, it is vital that the performance of EPIDs in clinical use is maintained at an optimal level through regular and rigorous quality assurance (QA). Traditionally, portal imaging QA has been carried out by imaging calibrated line-pair and contrast resolution phantoms and obtaining arbitrarily defined QA indices that are usually dependent on imaging conditions and merely indicate relative trends in imaging performance. They are not adequately sensitive to all aspects of image quality unlike fundamental imaging metrics such as the modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) that are widely used to characterize detector performance in radiographic imaging and would be ideal for QA purposes. However, due to the difficulty of performing conventional MTF measurements, they have not been used for routine clinical QA. The authors present a simple and quick QA methodology based on obtaining the MTF, NPS, and DQE of a megavoltage imager by imaging standard open fields and a bar-pattern QA phantom containing 2 mm thick tungsten line-pair bar resolution targets. Our bar-pattern based MTF measurement features a novel zero-frequency normalization scheme that eliminates normalization errors typically associated with traditional bar-pattern measurements at megavoltage x-ray energies. The bar-pattern QA phantom and open-field images are used in conjunction with an automated image analysis algorithm that quickly computes the MTF, NPS, and DQE of an EPID system. Our approach combines the fundamental advantages of

  9. Assessment of flatness and symmetry of megavoltage x-ray beam with an electronic portal imaging device

    CERN Document Server

    Liu, G; Bezak, E

    2002-01-01

    The input/output characteristics of the Wellhofer BIS 710 electronic portal imaging device (EPID) have been investigated to establish its efficacy for periodic quality assurance (QA) applications. Calibration curves have been determined for the energy fluence incident on the detector versus the pixel values. The effect of the charge coupled device (CCD) camera sampling time and beam parameters (such as beam field size, dose rate, photon energy) on the calibration have been investigated for a region of interest (ROI) around the central beam axis. The results demonstrate that the pixel output is a linear function of the incident exposure, as expected for a video-based electronic portal imaging system. The field size effects of the BIS 710 are similar to that of an ion chamber for smaller field sizes up to 10 x 10 cm sup 2. However, for larger field sizes the pixel value increases more rapidly. Furthermore, the system is slightly sensitive to dose rate and is also energy dependent. The BIS 710 has been used in t...

  10. Development of an IMRT quality assurance program using an amorphous silicon electronic portal imaging device

    International Nuclear Information System (INIS)

    Hunt, P.; Oliver, L.; Mallik, A.

    2000-01-01

    Full text: Quality Assurance (QA) for an intensity modulated radiotherapy (IMRT) megavoltage beam is a complex task. The positional accuracy of the MLC; its radiation leakage; the overall distribution of the dose delivered as compared to the treatment plan and; the accuracy of the calculated monitor units to deliver this dose, are all important parameters to clinically monitor. We are presently assessing the Varian version 6 software package with CadPlan, Helios with IMRT and inverse planning, VARiS Vision and the linear accelerator DMLC controller. Whilst conventional QA tools such as ionisation chamber and film measurements are used, these methods are inconvenient for directly monitoring an IMRT patient treatment. Varian Medical Systems has developed an improved electronic portal imaging device (EPID) with an amorphous silicon (a-Si) detector array. The A-Si has a sensitive area of 40x30cm and an improved image resolution of 512x384 pixels. Images are recorded at approximately 7-10 frames per second for an exposure rate of 100-600 MU/minute. Although the A-Si was designed as an EPID for a static treatment field, this new device could be a valuable IMRT QA tool for a range of different tests. Measurements taken on the RNSH and Varian prototype A-Si EPI devices showed a linear dose response for 6-18MeV X-ray energy. In addition to the Varian IAS2 internal software handlers, we have developed some image data handling programs to view and analyse these images in more detail. The software is primarily used to view the images; measure the reading in a region of interest or profile; or merge, overlay, add or subtract images during the analysis. The small pixel resolution provides a reliable, highly accurate means of measuring beam size, leaf position, MLC radiation leakage or profile intensity curves with a positional accuracy of 0.8mm. The images produced by an IMRT exposure is clearly discernible and appears consistent with the result expected. Step wedge images

  11. Effects of respiration on target and critical structure positions during treatment assessed with movie-loop electronic portal imaging

    International Nuclear Information System (INIS)

    Herman, Michael G.; Khadivi, Kevin O.; Kleinberg, Lawrence; Gage, Irene; Abrams, Ross A.

    1997-01-01

    Purpose: To determine the extent of organ and target motion due to patient respiration during chest radiotherapy using electronic portal imaging, to examine these effects on treatment volumes and to show that simulation and treatment port films do not reflect this range of motion. Materials and Methods: Twenty four patients consisting of 17 tangential breast and 7 AP-PA lung field arrangements were imaged during daily radiation treatment. Eight to 10 sequential movie-loop images were acquired during each field of each fraction with a liquid ion chamber electronic portal imaging device (EPID). Motion relative to the reference image was assessed orthogonally to the central axis of the beam. In tangential breast images, cranial, caudad and lateral lung-chest wall landmarks were used; for AP-PA lung, visible tumor, mediastinum and bronchus. Inter and intra-fractional landmark displacements were determined through off-line analysis. Intra-fractional displacements, determined from multiple images within one fraction, indicate motion of the landmark during treatment. Inter-fractional data represents motion between treatment fractions as seen in routine portal film imaging. The effects on treatment volumes were assessed for the largest displacements using the EPID data together with CT reconstruction. Results: The mean, maximum and standard deviation (σ) for observed respiration induced displacements in the cranio-caudad (CC) and lateral directions relative to the beam are summarized both within (intra) and between (inter) fractions: These data indicate that while the mean displacements are small, the standard deviations are significant and the maximum motion observed during a fraction due to respiration may exceed 3 cm in certain cases. In addition, the intra-fractional displacements significantly exceed the inter-fractional displacements, which suggests that anatomical motion is not fully quantified in routine portal imaging. In lung treatments where the largest

  12. SIFT: A method to verify the IMRT fluence delivered during patient treatment using an electronic portal imaging device

    International Nuclear Information System (INIS)

    Vieira, Sandra C.; Dirkx, Maarten L.P.; Heijmen, Ben J.M.; Boer, Hans C.J. de

    2004-01-01

    Purpose: Radiotherapy patients are increasingly treated with intensity-modulated radiotherapy (IMRT) and high tumor doses. As part of our quality control program to ensure accurate dose delivery, a new method was investigated that enables the verification of the IMRT fluence delivered during patient treatment using an electronic portal imaging device (EPID), irrespective of changes in patient geometry. Methods and materials: Each IMRT treatment field is split into a static field and a modulated field, which are delivered in sequence. Images are acquired for both fields using an EPID. The portal dose image obtained for the static field is used to determine changes in patient geometry between the planning CT scan and the time of treatment delivery. With knowledge of these changes, the delivered IMRT fluence can be verified using the portal dose image of the modulated field. This method, called split IMRT field technique (SIFT), was validated first for several phantom geometries, followed by clinical implementation for a number of patients treated with IMRT. Results: The split IMRT field technique allows for an accurate verification of the delivered IMRT fluence (generally within 1% [standard deviation]), even if large interfraction changes in patient geometry occur. For interfraction radiological path length changes of 10 cm, deliberately introduced errors in the delivered fluence could still be detected to within 1% accuracy. Application of SIFT requires only a minor increase in treatment time relative to the standard IMRT delivery. Conclusions: A new technique to verify the delivered IMRT fluence from EPID images, which is independent of changes in the patient geometry, has been developed. SIFT has been clinically implemented for daily verification of IMRT treatment delivery

  13. Two-dimensional exit dosimetry using a liquid-filled electronic portal imaging device and a convolution model

    International Nuclear Information System (INIS)

    Boellaard, Ronald; Herk, Marcel van; Uiterwaal, Hans; Mijnheer, Ben

    1997-01-01

    Background and purpose: To determine the accuracy of two-dimensional exit dose measurements with an electronic portal imaging device, EPID, using a convolution model for a variety of clinically relevant situations. Materials and methods: Exit doses were derived from portal dose images, obtained with a liquid-filled EPID at distances of 50 cm or more behind the patient, by using a convolution model. The resulting on- and off-axis exit dose values were first compared with ionization chamber exit dose measurements for homogeneous and inhomogeneous phantoms in open and wedged 4,8 and 18 MV photon beams. The accuracy of the EPID exit dose measurements was then determined for a number of anthropomorphic phantoms (lung and larynx) irradiated under clinical conditions and for a few patients treated in an 8 MV beam. The latter results were compared with in vivo exit dose measurements using diodes. Results: The exit dose can be determined from portal images with an accuracy of 1.2% (1 SD) compared with ionization chamber measurements for open beams and homogeneous phantoms at all tested beam qualities. In the presence of wedges and for inhomogeneous phantoms the average relative accuracy slightly deteriorated to 1.7% (1 SD). For lung phantoms in a 4 MV beam a similar accuracy was obtained after refinement of our convolution model, which requires knowledge of the patient contour. Differences between diode and EPID exit dose measurements for an anthropomorphic lung phantom in an 8 MV beam were 2.5% at most, with an average agreement within 1% (1 SD). For larynx phantoms in a 4 MV beam exit doses obtained with an ionization chamber and EPID agreed within 1.5% (1 SD). Finally, exit doses in a few patients irradiated in an 8 MV beam could be determined with the EPID with an accuracy of 1.1% (1 SD) relative to exit dose measurements using diodes. Conclusions: Portal images, obtained with our EPID and analyzed with our convolution model, can be used to determine the exit dose

  14. Feasibility study using a Ni-Ti stent and electronic portal imaging to localize the prostate during radiotherapy.

    Science.gov (United States)

    Carl, Jesper; Lund, Bente; Larsen, Erik Hoejkjaer; Nielsen, Jane

    2006-02-01

    A new method for localization of the prostate during external beam radiotherapy is presented. The method is based on insertion of a thermo-expandable Ni-Ti stent. The stent is originally developed for treatment of bladder outlet obstruction caused by benign hyperplasia. The radiological properties of the stent are used for precise prostate localization during treatment using electronic portal images. Patients referred for intended curative radiotherapy and having a length of their prostatic urethra in the range from 25 to 65 mm were included. Pairs of isocentric orthogonal portal images were used to determine the 3D position at eight different treatment sessions for each patient. Fourteen patients were enrolled in the study. The data obtained demonstrated that the stent position was representative of the prostate location. The stent may also improve delineation of the prostate GTV, and prevent obstruction of bladder outlet during treatment. Precision in localization of the stent was less than 1 mm. Random errors in stent position were left-right 1.6 mm, cranial-caudal 2.2 mm and anterior-posterior 3.2 mm. In four of 14 patients a dislocation of the stent to the bladder occurred. Dislocation only occurred in patients with length of prostatic urethra less than 40 mm. A new method for radiological high precision localization of the prostate during radiotherapy is presented. The method is based on insertion of a standard Ni-Ti thermo-expandable stent, designed for treatment of benign prostate hyperplasia.

  15. Development of a one-stop beam verification system using electronic portal imaging devices for routine quality assurance

    International Nuclear Information System (INIS)

    Lim, Sangwook; Ma, Sun Young; Jeung, Tae Sig; Yi, Byong Yong; Lee, Sang Hoon; Lee, Suk; Cho, Sam Ju; Choi, Jinho

    2012-01-01

    In this study, a computer-based system for routine quality assurance (QA) of a linear accelerator (linac) was developed by using the dosimetric properties of an amorphous silicon electronic portal imaging device (EPID). An acrylic template phantom was designed such that it could be placed on the EPID and be aligned with the light field of the collimator. After irradiation, portal images obtained from the EPID were transferred in DICOM format to a computer and analyzed using a program we developed. The symmetry, flatness, field size, and congruence of the light and radiation fields of the photon beams from the linac were verified simultaneously. To validate the QA system, the ion chamber and film (X-Omat V2; Kodak, New York, NY) measurements were compared with the EPID measurements obtained in this study. The EPID measurements agreed with the film measurements. Parameters for beams with energies of 6 MV and 15 MV were obtained daily for 1 month using this system. It was found that our QA tool using EPID could substitute for the film test, which is a time-consuming method for routine QA assessment.

  16. Development of a one-stop beam verification system using electronic portal imaging devices for routine quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Sangwook, E-mail: medicalphysics@hotmail.com [Department of Radiation Oncology, Kosin University College of Medicine, Seo-gu, Busan (Korea, Republic of); Ma, Sun Young; Jeung, Tae Sig [Department of Radiation Oncology, Kosin University College of Medicine, Seo-gu, Busan (Korea, Republic of); Yi, Byong Yong [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD (United States); Lee, Sang Hoon [Department of Radiation Oncology, Cheil General Hospital and Women' s Healthcare Center, Kwandong University College of Medicine, Jung-gu, Seoul (Korea, Republic of); Lee, Suk [Department of Radiation Oncology, College of Medicine, Korea University, Seongbuk-gu, Seoul (Korea, Republic of); Cho, Sam Ju [Department of Radiation Oncology, Eulji University School of Medicine, Eulji General Hospital, Nowon-gu, Seoul (Korea, Republic of); Choi, Jinho [Department of Radiation Oncology, Gachon University of Medicine and Science, Namdong-gu, Incheon (Korea, Republic of)

    2012-10-01

    In this study, a computer-based system for routine quality assurance (QA) of a linear accelerator (linac) was developed by using the dosimetric properties of an amorphous silicon electronic portal imaging device (EPID). An acrylic template phantom was designed such that it could be placed on the EPID and be aligned with the light field of the collimator. After irradiation, portal images obtained from the EPID were transferred in DICOM format to a computer and analyzed using a program we developed. The symmetry, flatness, field size, and congruence of the light and radiation fields of the photon beams from the linac were verified simultaneously. To validate the QA system, the ion chamber and film (X-Omat V2; Kodak, New York, NY) measurements were compared with the EPID measurements obtained in this study. The EPID measurements agreed with the film measurements. Parameters for beams with energies of 6 MV and 15 MV were obtained daily for 1 month using this system. It was found that our QA tool using EPID could substitute for the film test, which is a time-consuming method for routine QA assessment.

  17. Optimisation of the imaging and dosimetric characteristics of an electronic portal imaging device employing plastic scintillating fibres using Monte Carlo simulations.

    Science.gov (United States)

    Blake, S J; McNamara, A L; Vial, P; Holloway, L; Kuncic, Z

    2014-11-21

    A Monte Carlo model of a novel electronic portal imaging device (EPID) has been developed using Geant4 and its performance for imaging and dosimetry applications in radiotherapy has been characterised. The EPID geometry is based on a physical prototype under ongoing investigation and comprises an array of plastic scintillating fibres in place of the metal plate/phosphor screen in standard EPIDs. Geometrical and optical transport parameters were varied to investigate their impact on imaging and dosimetry performance. Detection efficiency was most sensitive to variations in fibre length, achieving a peak value of 36% at 50 mm using 400 keV x-rays for the lengths considered. Increases in efficiency for longer fibres were partially offset by reductions in sensitivity. Removing the extra-mural absorber surrounding individual fibres severely decreased the modulation transfer function (MTF), highlighting its importance in maximising spatial resolution. Field size response and relative dose profile simulations demonstrated a water-equivalent dose response and thus the prototype's suitability for dosimetry applications. Element-to-element mismatch between scintillating fibres and underlying photodiode pixels resulted in a reduced MTF for high spatial frequencies and quasi-periodic variations in dose profile response. This effect is eliminated when fibres are precisely matched to underlying pixels. Simulations strongly suggest that with further optimisation, this prototype EPID may be capable of simultaneous imaging and dosimetry in radiotherapy.

  18. Optimisation of the imaging and dosimetric characteristics of an electronic portal imaging device employing plastic scintillating fibres using Monte Carlo simulations

    Science.gov (United States)

    Blake, S. J.; McNamara, A. L.; Vial, P.; Holloway, L.; Kuncic, Z.

    2014-11-01

    A Monte Carlo model of a novel electronic portal imaging device (EPID) has been developed using Geant4 and its performance for imaging and dosimetry applications in radiotherapy has been characterised. The EPID geometry is based on a physical prototype under ongoing investigation and comprises an array of plastic scintillating fibres in place of the metal plate/phosphor screen in standard EPIDs. Geometrical and optical transport parameters were varied to investigate their impact on imaging and dosimetry performance. Detection efficiency was most sensitive to variations in fibre length, achieving a peak value of 36% at 50 mm using 400 keV x-rays for the lengths considered. Increases in efficiency for longer fibres were partially offset by reductions in sensitivity. Removing the extra-mural absorber surrounding individual fibres severely decreased the modulation transfer function (MTF), highlighting its importance in maximising spatial resolution. Field size response and relative dose profile simulations demonstrated a water-equivalent dose response and thus the prototype’s suitability for dosimetry applications. Element-to-element mismatch between scintillating fibres and underlying photodiode pixels resulted in a reduced MTF for high spatial frequencies and quasi-periodic variations in dose profile response. This effect is eliminated when fibres are precisely matched to underlying pixels. Simulations strongly suggest that with further optimisation, this prototype EPID may be capable of simultaneous imaging and dosimetry in radiotherapy.

  19. Electronic health records and cardiac implantable electronic devices: new paradigms and efficiencies.

    Science.gov (United States)

    Slotwiner, David J

    2016-10-01

    The anticipated advantages of electronic health records (EHRs)-improved efficiency and the ability to share information across the healthcare enterprise-have so far failed to materialize. There is growing recognition that interoperability holds the key to unlocking the greatest value of EHRs. Health information technology (HIT) systems including EHRs must be able to share data and be able to interpret the shared data. This requires a controlled vocabulary with explicit definitions (data elements) as well as protocols to communicate the context in which each data element is being used (syntactic structure). Cardiac implantable electronic devices (CIEDs) provide a clear example of the challenges faced by clinicians when data is not interoperable. The proprietary data formats created by each CIED manufacturer, as well as the multiple sources of data generated by CIEDs (hospital, office, remote monitoring, acute care setting), make it challenging to aggregate even a single patient's data into an EHR. The Heart Rhythm Society and CIED manufacturers have collaborated to develop and implement international standard-based specifications for interoperability that provide an end-to-end solution, enabling structured data to be communicated from CIED to a report generation system, EHR, research database, referring physician, registry, patient portal, and beyond. EHR and other health information technology vendors have been slow to implement these tools, in large part, because there have been no financial incentives for them to do so. It is incumbent upon us, as clinicians, to insist that the tools of interoperability be a prerequisite for the purchase of any and all health information technology systems.

  20. Knowledge, workflow and electronic document management in the system of the State Nuclear Regulatory Inspectorate of Ukraine. Preparing the platform development and implementation of the Knowledge Portal

    International Nuclear Information System (INIS)

    Bozhko, S.G.; Shevchenko, Yi.A.; Pecheritsya, O.V.; Singayivs'kij, A.M.

    2016-01-01

    The previous paper considered the creation of the system for management of nuclear knowledge, workflow and electronic documents (hereinafter called the Knowledge Portal) in the field of safe nuclear energy use. It presented initial steps needed to make an informed decision on the feasibility of implementing the Knowledge Portal and proposed methodological approaches based on practical experience of the State Nuclear Regulatory Inspectorate of Ukraine and the SSTC NRS. Further pre - project activities of the state body, local authorities, enterprises, institutions and organizations irrespective of ownership (hereinafter called the Institution) involve the development and drawing attention to the package of analytical, technical and feasibility documents. In particular, it is recommended to take into account the results of analyzing world trends in the development of information technology, audit status information and telecommunication systems (hereinafter - ITS) of the Institution, detailed strategy for the development of ITS Institution (hereinafter - the Strategy), the concept of the Knowledge Portal (hereinafter - the Concept) and preliminary technical solution The results of review and approval of the Concept and architecture solution by scientific and technical council of the Institution is the basis for the preparation of Ter ms of Reference (hereinafter - TOR) on the development of the Knowledge Portal, forming schedules for the procurement of hardware and software, works on the development and implementation of portal solutions and information security systems

  1. Feasibility study using a Ni-Ti stent and electronic portal imaging to localize the prostate during radiotherapy

    International Nuclear Information System (INIS)

    Carl, Jesper; Lund, Bente; Larsen, Erik Hoejkjaer; Nielsen, Jane

    2006-01-01

    Background and purpose: A new method for localization of the prostate during external beam radiotherapy is presented. The method is based on insertion of a thermo-expandable Ni-Ti stent. The stent is originally developed for treatment of bladder outlet obstruction caused by benign hyperplasia. The radiological properties of the stent are used for precise prostate localization during treatment using electronic portal images. Patients and methods: Patients referred for intended curative radiotherapy and having a length of their prostatic urethra in the range from 25 to 65 mm were included. Pairs of isocentric orthogonal portal images were used to determine the 3D position at eight different treatment sessions for each patient. Results: Fourteen patients were enrolled in the study. The data obtained demonstrated that the stent position was representative of the prostate location. The stent may also improve delineation of the prostate GTV, and prevent obstruction of bladder outlet during treatment. Precision in localization of the stent was less than 1 mm. Random errors in stent position were left-right 1.6 mm, cranial-caudal 2.2 mm and anterior-posterior 3.2 mm. In four of 14 patients a dislocation of the stent to the bladder occurred. Dislocation only occurred in patients with length of prostatic urethra less than 40 mm. Conclusions: A new method for radiological high precision localization of the prostate during radiotherapy is presented. The method is based on insertion of a standard Ni-Ti thermo-expandable stent, designed for treatment of benign prostate hyperplasia

  2. Fast, daily linac verification for segmented IMRT using electronic portal imaging

    International Nuclear Information System (INIS)

    Vieira, Sandra C.; Bolt, Rene A.; Dirkx, Maarten L.P.; Visser, Andries G.; Heijmen, Ben J.M.

    2006-01-01

    Purpose: Intensity modulated radiotherapy (IMRT) requires dedicated quality assurance (QA). Recently, we have published a method for fast (1-2 min) and accurate linac quality control for dynamic multileaf collimation, using a portal imaging device. This method is in routine use for daily leaf motion verification. The purpose of the present study was to develop an equivalent procedure for QA of IMRT with segmented (static) multileaf collimation (SMLC). Materials and methods: The QA procedure is based on measurements performed during 3- to 8-month periods at Elekta, Siemens and Varian accelerators. On each measurement day, images were acquired for a field consisting of five 3 x 22 cm 2 segments. These 10 monitor unit (MU) segments were delivered in SMLC mode, moving the leaves from left to right. Deviations of realized leaf gap widths from the prescribed width were analysed to study the leaf positioning accuracy. To assess hysteresis in leaf positioning, the sequential delivery of the SMLC segments was also inverted. A static 20 x 20 cm 2 field was delivered with exposures between 1 and 50 MU to study the beam output and beam profile at low exposures. Comparisons with an ionisation chamber were made to verify the EPID dose measurements at low MU. Dedicated software was developed to improve the signal-to-noise ratio and to correct for image distortion. Results and conclusions: The observed long-term leaf gap reproducibility (1 standard deviation) was 0.1 mm for the Varian, and 0.2 mm for the Siemens and the Elekta accelerators. In all cases the hysteresis was negligible. Down to the lowest MU, beam output measurements performed with the EPID agreed within 1 ± 1% (1SD) with ionisation chamber measurements. These findings led to a fast (3-4 min) procedure for accurate, daily linac quality control for SMLC

  3. Initial Empirical Research With an Experimental Secure Web Portal of Electronics Records Archives

    National Research Council Canada - National Science Library

    Nguyen, Binh; Racine, Glenn

    2005-01-01

    ...). The purpose of this collaborative work was to facilitate the processing and the protection of distributed authentic electronic records archives (ERA) for the U.S. National Archives and Records Administration (NARA).

  4. The use of gold markers and electronic portal imaging for radiotherapy verification in prostate cancer patients: Sweden Ghana Medical Centre experience

    Directory of Open Access Journals (Sweden)

    George Felix Acquah

    2014-02-01

    Full Text Available The success of radiotherapy cancer treatment delivery depends on the accuracy of patient setup for each fraction. A significant problem arises from reproducing the same patient position and prostate location during treatment planning for every fraction of the treatment process. To analyze the daily movements of the prostate, gold markers are implanted in the prostate and portal images taken and manually matched with reference images to locate the prostate. Geometrical and fiducial markers are annotated onto a highly quality generated digitally reconstructed radiographs, that are compared with portal images acquired right before treatment dose delivery. A 0 and 270 degree treatment fields are used to calculate prostate shifts for all prostate cancer patients undergoing treatment at the Sweden Ghana Medical Centre, using an iViewGT portal imaging device. After aligning of the marker positions onto the reference images, the set-up deviations corrections are displayed and an on-line correction procedure applied. The measured migrations of the prostate markers are below the threshold of 3 mm for the main plans and 2 mm for the boost plans. With daily electronic portal imaging combined with gold markers, provides an objective method for verifying and correcting the position of the prostate immediately prior to radiation delivery.--------------------------------------------Cite this article as: Acquah GF. The use of gold markers and electronic portal imaging for radiotherapy verification in prostate cancer patients: Sweden Ghana Medical Centre experience. Int J Cancer Ther Oncol 2014; 2(1:020112.DOI: http://dx.doi.org/10.14319/ijcto.0201.12

  5. Economic efficiency analysis of electron accelerator for irradiation processing

    International Nuclear Information System (INIS)

    Shi Huidong; Chen Ronghui

    2003-01-01

    The fixed assets, running cost and economic efficiency were discussed in this paper. For building electron accelerator of 10 MeV and 3 kW, the running cost is one time higher than building cobalt source at 2.22 x 10 15 Bq, but economic efficiency of building a electron accelerator is much higher than building a cobalt source

  6. The development of efficient coding for an electronic mail system

    Science.gov (United States)

    Rice, R. F.

    1983-01-01

    Techniques for efficiently representing scanned electronic documents were investigated. Major results include the definition and preliminary performance results of a Universal System for Efficient Electronic Mail (USEEM), offering a potential order of magnitude improvement over standard facsimile techniques for representing textual material.

  7. Investigation of the mechanical performance of Siemens linacs components during arc: gantry, MLC, and electronic portal imaging device.

    Science.gov (United States)

    Rowshanfarzad, Pejman; Häring, Peter; Riis, Hans L; Zimmermann, Sune J; Ebert, Martin A

    2015-01-01

    In radiotherapy treatments, it is crucial to monitor the performance of linac components including gantry, collimation system, and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method is suggested in conjunction with an algorithm to investigate the stability of these systems at various gantry angles with the aim of evaluating machine-related errors in treatments. The EPID sag, gantry sag, changes in source-to-detector distance (SDD), EPID and collimator skewness, EPID tilt, and the sag in leaf bank assembly due to linac rotation were separately investigated by acquisition of 37 EPID images of a simple phantom with five ball bearings at various gantry angles. A fast and robust software package was developed for automated analysis of image data. Three Siemens linacs were investigated. The average EPID sag was within 1 mm for all tested linacs. Two machines showed >1 mm gantry sag. Changes in the SDD values were within 7.5 mm. EPID skewness and tilt values were <1° in all machines. The maximum sag in leaf bank assembly was <1 mm. The method and software developed in this study provide a simple tool for effective investigation of the behavior of Siemens linac components with gantry rotation. Such a comprehensive study has been performed for the first time on Siemens machines.

  8. SU-E-T-335: Transit Dosimetry for Verification of Dose Delivery Using Electronic Portal Imaging Device (EPID)

    Energy Technology Data Exchange (ETDEWEB)

    Baek, T [Korea University, Seoul (Korea, Republic of); National Health Insurance Co.Ilsan Hospital, Ilsan (Korea, Republic of); Chung, E [National Health Insurance Co.Ilsan Hospital, Ilsan (Korea, Republic of); Lee, S [Cheil General Hospital and Women Healthcare Center, Kwandong University, Seoul (Korea, Republic of); Yoon, M [Korea University, Seoul (Korea, Republic of)

    2014-06-01

    Purpose: To evaluate the effectiveness of transit dose, measured with an electronic portal imaging device (EPID), in verifying actual dose delivery to patients. Methods: Plans of 5 patients with lung cancer, who received IMRT treatment, were examined using homogeneous solid water phantom and inhomogeneous anthropomorphic phantom. To simulate error in patient positioning, the anthropomorphic phantom was displaced from 5 mm to 10 mm in the inferior to superior (IS), superior to inferior (SI), left to right (LR), and right to left (RL) directions. The transit dose distribution was measured with EPID and was compared to the planed dose using gamma index. Results: Although the average passing rate based on gamma index (GI) with a 3% dose and a 3 mm distance-to-dose agreement tolerance limit was 94.34 % for the transit dose with homogeneous phantom, it was reduced to 84.63 % for the transit dose with inhomogeneous anthropomorphic phantom. The Result also shows that the setup error of 5mm (10mm) in IS, SI, LR and SI direction can Result in the decrease in values of GI passing rates by 1.3% (3.0%), 2.2% (4.3%), 5.9% (10.9%), and 8.9% (16.3%), respectively. Conclusion: Our feasibility study suggests that the transit dose-based quality assurance may provide information regarding accuracy of dose delivery as well as patient positioning.

  9. Comparison of horizontal and vertical noise power spectrum in measurements by using various electronic portal imaging devices in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Won [Dept. of Radiology, Kyung Hee University Hospital at Gang-dong, Seoul (Korea, Republic of); Choi, Kwan Woo [Dept. of Radiology, Asan Medical Center, Seoul (Korea, Republic of); Jeong, Hoi Woun [Dept. of Radiological Technology, Baekseok Culture University, Cheonan (Korea, Republic of); Jang, Seo Goo [Dept. of Medical Science, Soonchunhyang University, Asan (Korea, Republic of); Kwon, Kyung Tae [Dept. of Radiological Technology, Dongnam Health University, Suwon (Korea, Republic of); Son, Soon Yong [Dept. of Radiological Technology, Wonkwang Health Science University, Iksan (Korea, Republic of); Son, Jin Hyun; Min, Jung Whan [Dept. of Radiological Technology, Shingu University, Sungnam (Korea, Republic of)

    2016-06-15

    The quality assurance (QA) is very important for diagnostic field and radiation therapy field to evaluate the characteristic of devices. The purpose of this study was to compare different NPS methodologies results which are measuring NPS with regard to horizontal and vertical directions by using megavoltage X-ray energies. The NPS evaluation methods were applied to the International Electro-technical Commission standard (IEC 62220-1). The electronic portal imaging devices (EPID) devices such as Siemens BEAMVIEWPLUS, Elekta iViewGT and Varian ClinacR iX aS1000 were used. NPS data were expressed by corresponding each frequency about average of noise value corresponding the each frequency, and NPS were evaluated quantitatively by totaling up the noise values of average frequency which are on horizontal and vertical directions. In NPS results for Elekta iViewGT, NPS of horizontal and vertical by using 4 methods were indicated the difference of 3-5% between horizontal and vertical direction. In the results of Siemens BEAMVIEWPLUS and Varian ClinacR iX aS1000, the NPS of horizontal and vertical direction were indicated the difference of 15% when averaging the whole values. This study were evaluated the NPS of each devices by totaling up the noise values of average frequency which are on horizontal and vertical directions suggesting the quantitative evaluation method using the data.

  10. Dosimetric properties of an amorphous silicon electronic portal imaging device for verification of dynamic intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Greer, Peter B.; Popescu, Carmen C.

    2003-01-01

    Dosimetric properties of an amorphous silicon electronic portal imaging device (EPID) for verification of dynamic intensity modulated radiation therapy (IMRT) delivery were investigated. The EPID was utilized with continuous frame-averaging during the beam delivery. Properties studied included effect of buildup, dose linearity, field size response, sampling of rapid multileaf collimator (MLC) leaf speeds, response to dose-rate fluctuations, memory effect, and reproducibility. The dependence of response on EPID calibration and a dead time in image frame acquisition occurring every 64 frames were measured. EPID measurements were also compared to ion chamber and film for open and wedged static fields and IMRT fields. The EPID was linear with dose and dose rate, and response to MLC leaf speeds up to 2.5 cm s-1 was found to be linear. A field size dependent response of up to 5% relative to d max ion-chamber measurement was found. Reproducibility was within 0.8% (1 standard deviation) for an IMRT delivery recorded at intervals over a period of one month. The dead time in frame acquisition resulted in errors in the EPID that increased with leaf speed and were over 20% for a 1 cm leaf gap moving at 1.0 cm s-1. The EPID measurements were also found to depend on the input beam profile utilized for EPID flood-field calibration. The EPID shows promise as a device for verification of IMRT, the major limitation currently being due to dead-time in frame acquisition

  11. Comparison of two methods for anterior-posterior isocenter localization in pelvic radiotherapy using electronic portal imaging

    International Nuclear Information System (INIS)

    Greer, Peter B.; Mortensen, Trina M.; Jose, C.C.

    1998-01-01

    Purpose: The two setup methods commonly used to determine the anterior-posterior isocenter location in pelvic radiotherapy are to align lateral localization lasers with lateral skin tattoos on the patient, or to set the couch height so that the isocenter is at a fixed height (determined during simulation or treatment planning) above the couch top. This study was implemented to determine which technique gives more accurate patient treatment by comparison of the anterior-posterior setup variation measured with electronic portal imaging. Methods and Materials: Eleven supine prostate patients were treated with tattoo localization and 159 left-lateral portal images were taken during the treatments. The field displacements were then determined by template matching. These patients were compared to nine patients (205 images) set up to a fixed isocenter height. Similarly, eight prone rectal patients (136 right-lateral images) set up to tattoos were compared to six patients (108 images) set up to a fixed height. The patients were not immobilized and were all treated with three field techniques on a hard couch top. The overall mean treatment position deviation and the standard deviation of the displacements (total setup variation) were calculated for each patient group along with the systematic (simulator-to-treatment) and the random (treatment-to-treatment) setup variation. Results: The mean treatment position deviations were 3.3 mm anterior and 5.2 mm posterior with the tattoo method for the prostate and rectal patients, respectively. These mean position deviations were 0.4/0.1 mm anterior with the fixed height technique. The total setup variations were 4.6/5.2 mm (1 SD) with tattoo localization and 1.7/1.5 mm (1 SD) with the fixed height method. Similarly, random variation was 2.3/3.3 mm (1 SD) with the tattoo method compared to 1.3/1.2 mm (1 SD) with the fixed height method. Systematic variation was 3.7/4.5 mm (1 SD) compared to 1.2/1.1 mm (1 SD). Conclusion: The fixed

  12. Efficient spin transitions in inelastic electron tunneling spectroscopy.

    Science.gov (United States)

    Lorente, Nicolás; Gauyacq, Jean-Pierre

    2009-10-23

    The excitation of the spin degrees of freedom of an adsorbed atom by tunneling electrons is computed using strong coupling theory. Recent measurements [Heinrich, Science 306, 466 (2004)] reveal that electron currents in a magnetic system efficiently excite its magnetic moments. Our theory shows that the incoming electron spin strongly couples with that of the adsorbate so that memory of the initial spin state is lost, leading to large excitation efficiencies. First-principles transmissions are evaluated in quantitative agreement with the experiment.

  13. WE-E-18A-08: Towards a Next-Generation Electronic Portal Device for Simultaneous Imaging and Dose Verification in Radiotherapy

    International Nuclear Information System (INIS)

    Blake, S; Vial, P; Holloway, L; Kuncic, Z

    2014-01-01

    Purpose: This work forms part of an ongoing study to develop a next-generation electronic portal imaging device (EPID) for simultaneous imaging and dose verification in radiotherapy. Monte Carlo (MC) simulations were used to characterize the imaging performance of a novel EPID that has previously been demonstrated to exhibit a water-equivalent response. The EPID ' s response was quantified in several configurations and model parameters were empirically validated against experimental measurements. Methods: A MC model of a novel a-Si EPID incorporating an array of plastic scintillating fibers was developed. Square BCF-99-06A scintillator fibers with PMMA cladding (Saint-Gobain Crystals) were modelled in a matrix with total area measuring 150×150 mm 2 . The standard electromagnetic and optical physics Geant4 classes were used to simulate radiation transport from an angled slit source (6 MV energy spectrum) through the EPID and optical photons reaching the photodiodes were scored. The prototype's modulation transfer function (MTF) was simulated and validated against experimental measurements. Several optical transport parameters, fiber lengths and thicknesses of an air gap between the scintillator and photodiodes were investigated to quantify their effects on the prototype's detection efficiency, sensitivity and MTF. Results: Simulated EPID response was more sensitive to variations in geometry than in the optical parameters studied. The MTF was particularly sensitive to the introduction of a 0.5–1.0 mm air gap between the scintillator and photodiodes, which lowered the MTF relative to that simulated without the gap. As expected, increasing the fiber length increased the detector efficiency and sensitivity while decreasing the MTF. Conclusion: A model of a novel water-equivalent EPID has been developed and benchmarked against measurements using a physical prototype. We have demonstrated the feasibility of this new device and are continuing to optimize

  14. Portal dosimetry in wedged beams

    NARCIS (Netherlands)

    Spreeuw, Hanno; Rozendaal, Roel; Camargo, Priscilla; Mans, Anton; Wendling, Markus; Olaciregui-Ruiz, Igor; Sonke, Jan-Jakob; van Herk, Marcel; Mijnheer, Ben

    2015-01-01

    Portal dosimetry using electronic portal imaging devices (EPIDs) is often applied to verify high-energy photon beam treatments. Due to the change in photon energy spectrum, the resulting dose values are, however, not very accurate in the case of wedged beams if the pixel-to-dose conversion for the

  15. Efficient communication in the electronic mail game

    NARCIS (Netherlands)

    de Jaegher, K.

    The literature on the electronic mail game shows that players’ mutual expectations may lock them into requiring an inefficiently large number of confirmations and confirmations of confirmations from one another. This paper shows that this result hinges on the assumption that, with the exception of

  16. Sharing Physician Notes Through an Electronic Portal is Associated With Improved Medication Adherence: Quasi-Experimental Study

    OpenAIRE

    Wright, Eric; Darer, Jonathan; Tang, Xiaoqin; Thompson, Jason; Tusing, Lorraine; Fossa, Alan; Delbanco, Tom; Ngo, Long; Walker, Jan

    2015-01-01

    Background In surveys, interviews, and focus groups, patients taking medications and offered Web portal access to their primary care physicians? (PCPs) notes report improved adherence to their regimens. However, objective confirmation has yet to be reported. Objective To evaluate the association between patient Internet portal access to primary care physician visit notes and medication adherence. Methods This study is a retrospective comparative analysis at one site of the OpenNotes quasi-exp...

  17. Benchmark test cases for evaluation of computer-based methods for detection of setup errors: realistic digitally reconstructed electronic portal images with known setup errors

    International Nuclear Information System (INIS)

    Fritsch, Daniel S.; Raghavan, Suraj; Boxwala, Aziz; Earnhart, Jon; Tracton, Gregg; Cullip, Timothy; Chaney, Edward L.

    1997-01-01

    Purpose: The purpose of this investigation was to develop methods and software for computing realistic digitally reconstructed electronic portal images with known setup errors for use as benchmark test cases for evaluation and intercomparison of computer-based methods for image matching and detecting setup errors in electronic portal images. Methods and Materials: An existing software tool for computing digitally reconstructed radiographs was modified to compute simulated megavoltage images. An interface was added to allow the user to specify which setup parameter(s) will contain computer-induced random and systematic errors in a reference beam created during virtual simulation. Other software features include options for adding random and structured noise, Gaussian blurring to simulate geometric unsharpness, histogram matching with a 'typical' electronic portal image, specifying individual preferences for the appearance of the 'gold standard' image, and specifying the number of images generated. The visible male computed tomography data set from the National Library of Medicine was used as the planning image. Results: Digitally reconstructed electronic portal images with known setup errors have been generated and used to evaluate our methods for automatic image matching and error detection. Any number of different sets of test cases can be generated to investigate setup errors involving selected setup parameters and anatomic volumes. This approach has proved to be invaluable for determination of error detection sensitivity under ideal (rigid body) conditions and for guiding further development of image matching and error detection methods. Example images have been successfully exported for similar use at other sites. Conclusions: Because absolute truth is known, digitally reconstructed electronic portal images with known setup errors are well suited for evaluation of computer-aided image matching and error detection methods. High-quality planning images, such as

  18. SU-E-T-438: Commissioning of An In-Vivo Quality Assurance Method Using the Electronic Portal Imaging Device

    International Nuclear Information System (INIS)

    Morin, O; Held, M; Pouliot, J

    2014-01-01

    Purpose: Patient specific pre-treatment quality assurance (QA) using arrays of detectors or film have been the standard approach to assure the correct treatment is delivered to the patient. This QA approach is expensive, labor intensive and does not guarantee or document that all remaining fractions were treated properly. The purpose of this abstract is to commission and evaluate the performance of a commercially available in-vivo QA software using the electronic portal imaging device (EPID) to record the daily treatments. Methods: The platform EPIgray V2.0.2 (Dosisoft), which machine model compares ratios of TMR with EPID signal to predict dose was commissioned for an Artiste (Siemens Oncology Care Systems) and a Truebeam (Varian medical systems) linear accelerator following the given instructions. The systems were then tested on three different phantoms (homogeneous stack of solid water, anthropomorphic head and pelvis) and on a library of patient cases. Simple and complex fields were delivered at different exposures and for different gantry angles. The effects of the table attenuation and the EPID sagging were evaluated. Gamma analysis of the measured dose was compared to the predicted dose for complex clinical IMRT cases. Results: Commissioning of the EPIgray system for two photon energies took 8 hours. The difference between the dose planned and the dose measured with EPIgray was better than 3% for all phantom scenarios tested. Preliminary results on patients demonstrate an accuracy of 5% is achievable in high dose regions for both 3DCRT and IMRT. Large discrepancies (>5%) were observed due to metallic structures or air cavities and in low dose areas. Flat panel sagging was visible and accounted for in the EPIgray model. Conclusion: The accuracy achieved by EPIgray is sufficient to document the safe delivery of complex IMRT treatments. Future work will evaluate EPIgray for VMAT and high dose rate deliveries. This work is supported by Dosisoft, Cachan, France

  19. Cost minimisation analysis: kilovoltage imaging with automated repositioning versus electronic portal imaging in image-guided radiotherapy for prostate cancer.

    Science.gov (United States)

    Gill, S; Younie, S; Rolfo, A; Thomas, J; Siva, S; Fox, C; Kron, T; Phillips, D; Tai, K H; Foroudi, F

    2012-10-01

    To compare the treatment time and cost of prostate cancer fiducial marker image-guided radiotherapy (IGRT) using orthogonal kilovoltage imaging (KVI) and automated couch shifts and orthogonal electronic portal imaging (EPI) and manual couch shifts. IGRT treatment delivery times were recorded automatically on either unit. Costing was calculated from real costs derived from the implementation of a new radiotherapy centre. To derive cost per minute for EPI and KVI units the total annual setting up and running costs were divided by the total annual working time. The cost per IGRT fraction was calculated by multiplying the cost per minute by the duration of treatment. A sensitivity analysis was conducted to test the robustness of our analysis. Treatment times without couch shift were compared. Time data were analysed for 8648 fractions, 6057 from KVI treatment and 2591 from EPI treatment from a total of 294 patients. The median time for KVI treatment was 6.0 min (interquartile range 5.1-7.4 min) and for EPI treatment it was 10.0 min (interquartile range 8.3-11.8 min) (P value time for EPI was 8.8 min and for KVI was 5.1 min. Treatment time is less on KVI units compared with EPI units. This is probably due to automation of couch shift and faster evaluation of imaging on KVI units. Annual running costs greatly outweigh initial setting up costs and therefore the cost per fraction was less with KVI, despite higher initial costs. The selection of appropriate IGRT equipment can make IGRT practical within radiotherapy departments. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  20. Automatic Prostate Tracking and Motion Assessment in Volumetric Modulated Arc Therapy With an Electronic Portal Imaging Device

    International Nuclear Information System (INIS)

    Azcona, Juan Diego; Li, Ruijiang; Mok, Edward; Hancock, Steven; Xing, Lei

    2013-01-01

    Purpose: To assess the prostate intrafraction motion in volumetric modulated arc therapy treatments using cine megavoltage (MV) images acquired with an electronic portal imaging device (EPID). Methods and Materials: Ten prostate cancer patients were treated with volumetric modulated arc therapy using a Varian TrueBeam linear accelerator equipped with an EPID for acquiring cine MV images during treatment. Cine MV images acquisition was scheduled for single or multiple treatment fractions (between 1 and 8). A novel automatic fiducial detection algorithm that can handle irregular multileaf collimator apertures, field edges, fast leaf and gantry movement, and MV image noise and artifacts in patient anatomy was used. All sets of images (approximately 25,000 images in total) were analyzed to measure the positioning accuracy of implanted fiducial markers and assess the prostate movement. Results: Prostate motion can vary greatly in magnitude among different patients. Different motion patterns were identified, showing its unpredictability. The mean displacement and standard deviation of the intrafraction motion was generally less than 2.0 ± 2.0 mm in each of the spatial directions. In certain patients, however, the percentage of the treatment time in which the prostate is displaced more than 5 mm from its planned position in at least 1 spatial direction was 10% or more. The maximum prostate displacement observed was 13.3 mm. Conclusion: Prostate tracking and motion assessment was performed with MV imaging and an EPID. The amount of prostate motion observed suggests that patients will benefit from its real-time monitoring. Megavoltage imaging can provide the basis for real-time prostate tracking using conventional linear accelerators

  1. Comparison of CT on Rails With Electronic Portal Imaging for Positioning of Prostate Cancer Patients With Implanted Fiducial Markers

    International Nuclear Information System (INIS)

    Owen, Rebecca; Kron, Tomas; Foroudi, Farshad; Milner, Alvin; Cox, Jennifer; Duchesne, Gillian; Cleeve, Laurence; Zhu Li; Cramb, Jim; Sparks, Laura; Laferlita, Marcus

    2009-01-01

    Purpose: The objective of this investigation was to measure the agreement between in-room computed tomography (CT) on rails and electronic portal image (EPI) radiography. Methods and Materials: Agreement between the location of the center of gravity (COG) of fiducial markers (FMs) on CT and EPI images was determined in phantom studies and a patient cohort. A secondary analysis between the center of volume (COV) of the prostate on CT and the COG of FMs on CT and EPI was performed. Agreement was defined as the 95% probability of a difference of ≤3.0 mm between images. Systematic and random errors from CT and EPI are reported. Results: From 8 patients, 254 CT and EPI pairs were analyzed. FMs were localized to within 3 mm on CT and EPI images 96.9% of the time in the left-right (LR) plane, 85.8% superior-inferior (SI), and 89% anterior-posterior (AP). The differences between the COV on CT and the COG on EPI were not within 3 mm in any plane: 87.8% (LR), 64.2% (SI), and 70.9% (AP). The systematic error varied from 1.2 to 2.9 mm (SI) and 1.8-2.9 mm (AP) between the COG on EPI and COV on CT. Conclusions: Considerable differences between in-room CT and EPI exist. The phantom measurements showed slice thickness affected the accuracy of localization in the SI plane, and couch sag that occurs at the CT on rails gantry could not be totally corrected for in the AP plane. Other confounding factors are the action of rotating the couch and associated time lag between image acquisitions (prostate motion), EPI image quality, and outlining uncertainties.

  2. SU-E-T-781: Using An Electronic Portal Imaging Device (EPID) for Correlating Linac Photon Beam Energies

    Energy Technology Data Exchange (ETDEWEB)

    Yaddanapudi, S; Cai, B; Sun, B; Noel, C; Goddu, S; Mutic, S [Washington University School of Medicine, Saint Louis, MO (United States)

    2015-06-15

    Purpose: Electronic portal imaging devices (EPIDs) have proven to be useful for measuring several parameters of interest in linear accelerator (linac) quality assurance (QA). The purpose of this project was to evaluate the feasibility of using EPIDs for determining linac photon beam energies. Methods: Two non-clinical Varian TrueBeam linacs (Varian Medical Systems, Palo Alto, CA) with 6MV and 10MV photon beams were used to perform the measurements. The linacs were equipped with an amorphous silicon based EPIDs (aSi1000) that were used for the measurements. We compared the use of flatness versus percent depth dose (PDD) for predicting changes in linac photon beam energy. PDD was measured in 1D water tank (Sun Nuclear Corporation, Melbourne FL) and the profiles were measured using 2D ion-chamber array (IC-Profiler, Sun Nuclear) and the EPID. Energy changes were accomplished by varying the bending magnet current (BMC). The evaluated energies conformed with the AAPM TG142 tolerance of ±1% change in PDD. Results: BMC changes correlating with a ±1% change in PDD corresponded with a change in flatness of ∼1% to 2% from baseline values on the EPID. IC Profiler flatness values had the same correlation. We observed a similar trend for the 10MV beam energy changes. Our measurements indicated a strong correlation between changes in linac photon beam energy and changes in flatness. For all machines and energies, beam energy changes produced change in the uniformity (AAPM TG-142), varying from ∼1% to 2.5%. Conclusions: EPID image analysis of beam profiles can be used to determine linac photon beam energy changes. Flatness-based metrics or uniformity as defined by AAPM TG-142 were found to be more sensitive to linac photon beam energy changes than PDD. Research funding provided by Varian Medical Systems. Dr. Sasa Mutic receives compensation for providing patient safety training services from Varian Medical Systems, the sponsor of this study.

  3. Investigation of the mechanical performance of Siemens linacs components during arc: gantry, MLC, and electronic portal imaging device

    Directory of Open Access Journals (Sweden)

    Rowshanfarzad P

    2015-11-01

    Full Text Available Pejman Rowshanfarzad,1 Peter Häring,2 Hans L Riis,3 Sune J Zimmermann,3 Martin A Ebert1,4 1School of Physics, The University of Western Australia, Crawley, WA, Australia; 2German Cancer Research Center (DKFZ, Medical Physics in Radiation Oncology, Heidelberg, Germany; 3Radiofysisk Laboratorium, Odense University Hospital, Odense C, Denmark; 4Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, Australia Background: In radiotherapy treatments, it is crucial to monitor the performance of linac components including gantry, collimation system, and electronic portal imaging device (EPID during arc deliveries. In this study, a simple EPID-based measurement method is suggested in conjunction with an algorithm to investigate the stability of these systems at various gantry angles with the aim of evaluating machine-related errors in treatments. Methods: The EPID sag, gantry sag, changes in source-to-detector distance (SDD, EPID and collimator skewness, EPID tilt, and the sag in leaf bank assembly due to linac rotation were separately investigated by acquisition of 37 EPID images of a simple phantom with five ball bearings at various gantry angles. A fast and robust software package was developed for automated analysis of image data. Three Siemens linacs were investigated. Results: The average EPID sag was within 1 mm for all tested linacs. Two machines showed >1 mm gantry sag. Changes in the SDD values were within 7.5 mm. EPID skewness and tilt values were <1° in all machines. The maximum sag in leaf bank assembly was <1 mm. Conclusion: The method and software developed in this study provide a simple tool for effective investigation of the behavior of Siemens linac components with gantry rotation. Such a comprehensive study has been performed for the first time on Siemens machines. Keywords: linac, Siemens, arc, sag, EPID, gantry

  4. Set-up errors in radiotherapy for oesophageal cancers - Is electronic portal imaging or conebeam more accurate?

    International Nuclear Information System (INIS)

    Hawkins, Maria A.; Aitken, Alexandra; Hansen, Vibeke N.; McNair, Helen A.; Tait, Diana M.

    2011-01-01

    Purpose: To compare kV computed tomography (CBCT) with electronic portal imaging (EPI) and evaluate set-up variations in the anterior-posterior (AP), right-left (LR) and cranio-caudal (CC) directions and rotational variations: pitch, roll, and yaw, for oesophageal cancer patients treated with radical radiotherapy. Methods and materials: Twenty patients with locally advanced oesophageal cancer treated with chemoradiation were consented for this prospective ethics approved protocol. Patients were positioned using skin marks/tattoos, kV-CBCT scans (XVI) and EPI's were performed prior to treatment and registered to the planning CT scans and digitally reconstructed radiographs, respectively. XVI data was used to adjust patient setups before treatment delivery. A total of 122 EPI pairs and 207 CBCT scans were analysed. The systematic and random errors were calculated. Results: The systematic and random errors (mm) for XVI were 1.3, 1.7, 1.4 and 2.6, 3.9, 2.0 in RL, CC and AP direction, respectively, with EPI of similar magnitude. There was no correlation between the 2 modalities of imaging as 31.7% of all image pairs were discordant >3 mm and 12.5% >5 mm. XVI identified rotations >3 o in 44 images. Conclusions: EPI results in different position correction for verification of radiotherapy in oesophageal malignancies when compared with CBCT. CBCT verification offers adequate 3D volumetric image quality to improve the accuracy of treatment delivery for oesophageal malignancies in radiotherapy and should be used for image guidance.

  5. GEO portal

    Data.gov (United States)

    US Agency for International Development — The USAID GeoPortal is a new application that groups web-based capabilities for on-demand discovery of and access to geospatial content, services, expertise, and...

  6. Measurements of the Electron Reconstruction and Identification Efficiencies in ATLAS

    CERN Document Server

    Sommer, P; The ATLAS collaboration

    2014-01-01

    Isolated, high-energy electrons constitute a very clean signature at hadron collider experiments. As the final states of many Standard Model processes, as well as physics beyond the Standard Model, analyses at the ATLAS experiment heavily rely on electrons. A precise knowledge of the efficiency to correctly reconstruct and identify these electrons is thus important. In this contribution the measurement of these efficiencies is described. It is performed with a tag-and-probe method using $Z$ and $J/\\psi$ decays to electrons in $20.3\\,\\mathrm{fb}^{-1}$ of $pp$ collisions recorded in 2012 at $\\sqrt{s}=8$ TeV. The combination of the measurements results in identification efficiencies determined with an accuracy of a few per mil for electrons with a transverse energy of $E_{\\mathrm{T}}>30$ GeV.

  7. SU-F-T-486: A Simple Approach to Performing Light Versus Radiation Field Coincidence Quality Assurance Using An Electronic Portal Imaging Device (EPID)

    Energy Technology Data Exchange (ETDEWEB)

    Herchko, S; Ding, G [Vanderbilt University, Nashville, TN (United States)

    2016-06-15

    Purpose: To develop an accurate, straightforward, and user-independent method for performing light versus radiation field coincidence quality assurance utilizing EPID images, a simple phantom made of readily-accessible materials, and a free software program. Methods: A simple phantom consisting of a blocking tray, graph paper, and high-density wire was constructed. The phantom was used to accurately set the size of a desired light field and imaged on the electronic portal imaging device (EPID). A macro written for use in ImageJ, a free image processing software, was then use to determine the radiation field size utilizing the high density wires on the phantom for a pixel to distance calibration. The macro also performs an analysis on the measured radiation field utilizing the tolerances recommended in the AAPM Task Group #142. To verify the accuracy of this method, radiochromic film was used to qualitatively demonstrate agreement between the film and EPID results, and an additional ImageJ macro was used to quantitatively compare the radiation field sizes measured both with the EPID and film images. Results: The results of this technique were benchmarked against film measurements, which have been the gold standard for testing light versus radiation field coincidence. The agreement between this method and film measurements were within 0.5 mm. Conclusion: Due to the operator dependency associated with tracing light fields and measuring radiation fields by hand when using film, this method allows for a more accurate comparison between the light and radiation fields with minimal operator dependency. Removing the need for radiographic or radiochromic film also eliminates a reoccurring cost and increases procedural efficiency.

  8. SU-F-T-486: A Simple Approach to Performing Light Versus Radiation Field Coincidence Quality Assurance Using An Electronic Portal Imaging Device (EPID)

    International Nuclear Information System (INIS)

    Herchko, S; Ding, G

    2016-01-01

    Purpose: To develop an accurate, straightforward, and user-independent method for performing light versus radiation field coincidence quality assurance utilizing EPID images, a simple phantom made of readily-accessible materials, and a free software program. Methods: A simple phantom consisting of a blocking tray, graph paper, and high-density wire was constructed. The phantom was used to accurately set the size of a desired light field and imaged on the electronic portal imaging device (EPID). A macro written for use in ImageJ, a free image processing software, was then use to determine the radiation field size utilizing the high density wires on the phantom for a pixel to distance calibration. The macro also performs an analysis on the measured radiation field utilizing the tolerances recommended in the AAPM Task Group #142. To verify the accuracy of this method, radiochromic film was used to qualitatively demonstrate agreement between the film and EPID results, and an additional ImageJ macro was used to quantitatively compare the radiation field sizes measured both with the EPID and film images. Results: The results of this technique were benchmarked against film measurements, which have been the gold standard for testing light versus radiation field coincidence. The agreement between this method and film measurements were within 0.5 mm. Conclusion: Due to the operator dependency associated with tracing light fields and measuring radiation fields by hand when using film, this method allows for a more accurate comparison between the light and radiation fields with minimal operator dependency. Removing the need for radiographic or radiochromic film also eliminates a reoccurring cost and increases procedural efficiency.

  9. SU-F-P-36: Automation of Linear Accelerator Star Shot Measurement with Advanced XML Scripting and Electronic Portal Imaging Device

    International Nuclear Information System (INIS)

    Nguyen, N; Knutson, N; Schmidt, M; Price, M

    2016-01-01

    Purpose: To verify a method used to automatically acquire jaw, MLC, collimator and couch star shots for a Varian TrueBeam linear accelerator utilizing Developer Mode and an Electronic Portal Imaging Device (EPID). Methods: An XML script was written to automate motion of the jaws, MLC, collimator and couch in TrueBeam Developer Mode (TBDM) to acquire star shot measurements. The XML script also dictates MV imaging parameters to facilitate automatic acquisition and recording of integrated EPID images. Since couch star shot measurements cannot be acquired using a combination of EPID and jaw/MLC collimation alone due to a fixed imager geometry, a method utilizing a 5mm wide steel ruler placed on the table and centered within a 15×15cm2 open field to produce a surrogate of the narrow field aperture was investigated. Four individual star shot measurements (X jaw, Y jaw, MLC and couch) were obtained using our proposed as well as traditional film-based method. Integrated EPID images and scanned measurement films were analyzed and compared. Results: Star shot (X jaw, Y jaw, MLC and couch) measurements were obtained in a single 5 minute delivery using the TBDM XML script method compared to 60 minutes for equivalent traditional film measurements. Analysis of the images and films demonstrated comparable isocentricity results, agreeing within 0.3mm of each other. Conclusion: The presented automatic approach of acquiring star shot measurements using TBDM and EPID has proven to be more efficient than the traditional film approach with equivalent results.

  10. Highly efficient electron vortex beams generated by nanofabricated phase holograms

    Energy Technology Data Exchange (ETDEWEB)

    Grillo, Vincenzo, E-mail: vincenzo.grillo@nano.cnr.it [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); CNR-IMEM Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Carlo Gazzadi, Gian [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Karimi, Ebrahim [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Mafakheri, Erfan [Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Boyd, Robert W. [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Frabboni, Stefano [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy)

    2014-01-27

    We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science.

  11. High-efficiency free-electron laser results

    International Nuclear Information System (INIS)

    Boyer, K.; Baru, C.A.; Newnam, B.E.; Stein, W.E.; Warren, R.W.; Winston, J.G.; Young, L.M.

    1983-01-01

    Results obtained with a tapered-wiggler free-electron laser demonstrate the concepts proposed by Morton for enhanced efficiency and show deceleration of electrons by as much as 7%, and extraction of more than 3% of the total electron-beam energy as laser energy when the laser is operated as an amplifier. The experiment is presently being reconfigured to examine its performance as a laser oscillator

  12. Highly efficient electron vortex beams generated by nanofabricated phase holograms

    International Nuclear Information System (INIS)

    Grillo, Vincenzo; Carlo Gazzadi, Gian; Karimi, Ebrahim; Mafakheri, Erfan; Boyd, Robert W.; Frabboni, Stefano

    2014-01-01

    We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science

  13. ASH External Web Portal (External Portal) -

    Data.gov (United States)

    Department of Transportation — The ASH External Web Portal is a web-based portal that provides single sign-on functionality, making the web portal a single location from which to be authenticated...

  14. Portals in Higher and Further Education. EDNER (Formative Evaluation of the Distributed National Electronic Resource) Project. Issues Paper.

    Science.gov (United States)

    Manchester Metropolitan Univ. (England).

    This issues paper, fifth in a series of eight, is intended to distill formative evaluation questions on topics that are central to the development of the higher and further education information environment in the United Kingdom. The term "portal" is so widely used by so many people with so many different perspectives that definition is…

  15. Health literacy and patient portals.

    Science.gov (United States)

    Gu, Yulong; Orr, Martin; Warren, Jim

    2015-06-01

    Health literacy has been described as the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions. Improving health literacy may serve to promote concordance with therapy, engage patients in their own health care, and improve health outcomes. Patient portal technology aims at enabling patients and families to have easy access to key information in their own medical records and to communicate with their health care providers electronically. However, there is a gap in our understanding of how portals will improve patient outcome. The authors believe patient portal technology presents an opportunity to improve patient concordance with prescribed therapy, if adequate support is provided to equip patients (and family/carers) with the knowledge needed to utilise the health information available via the portals. Research is needed to understand what a health consumer will use patient portals for and how to support a user to realise the technology's potential.

  16. SU-G-BRA-06: Quantification of Tracking Performance of a Multi-Layer Electronic Portal Imaging Device

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Y; Rottmann, J; Myronakis, M; Berbeco, R [Department of Radiation Oncology, Brigham and Women’s Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: The purpose of this study was to quantify the improvement in tumor tracking, with and without fiducial markers, afforded by employing a multi-layer (MLI) electronic portal imaging device (EPID) over the current state-of-the-art, single-layer, digital megavolt imager (DMI) architecture. Methods: An ideal observer signal-to-noise ratio (d’) approach was used to quantify the ability of an MLI EPID and a current, state-of-the-art DMI EPID to track lung tumors from the treatment beam’s-eye-view. Using each detector modulation transfer function (MTF) and noise power spectrum (NPS) as inputs, a detection task was employed with object functions describing simple three-dimensional Cartesian shapes (spheres and cylinders). Marker-less tumor tracking algorithms often use texture discrimination to differentiate benign and malignant tissue. The performance of such algorithms is simulated by employing a discrimination task for the ideal observer, which measures the ability of a system to differentiate two image quantities. These were defined as the measured textures for benign and malignant lung tissue. Results: The NNPS of the MLI ∼25% of that of the DMI at the expense of decreased MTF at intermediate frequencies (0.25≤

  17. Conditions for reliable time-resolved dosimetry of electronic portal imaging devices for fixed-gantry IMRT and VMAT

    International Nuclear Information System (INIS)

    Yeo, Inhwan Jason; Patyal, Baldev; Mandapaka, Anant; Jung, Jae Won; Yi, Byong Yong; Kim, Jong Oh

    2013-01-01

    Purpose: The continuous scanning mode of electronic portal imaging devices (EPID) that offers time-resolved information has been newly explored for verifying dynamic radiation deliveries. This study seeks to determine operating conditions (dose rate stability and time resolution) under which that mode can be used accurately for the time-resolved dosimetry of intensity-modulated radiation therapy (IMRT) beams.Methods: The authors have designed the following test beams with variable beam holdoffs and dose rate regulations: a 10 × 10 cm open beam to serve as a reference beam; a sliding window (SW) beam utilizing the motion of a pair of multileaf collimator (MLC) leaves outside the 10 × 10 cm jaw; a step and shoot (SS) beam to move the pair in step; a volumetric modulated arc therapy (VMAT) beam. The beams were designed in such a way that they all produce the same open beam output of 10 × 10 cm. Time-resolved ion chamber measurements at isocenter and time-resolved and integrating EPID measurements were performed for all beams. The time-resolved EPID measurements were evaluated through comparison with the ion chamber and integrating EPID measurements, as the latter are accepted procedures. For two-dimensional, time-resolved evaluation, a VMAT beam with an infield MLC travel was designed. Time-resolved EPID measurements and Monte Carlo calculations of such EPID dose images for this beam were performed and intercompared.Results: For IMRT beams (SW and SS), the authors found disagreement greater than 2%, caused by frame missing of the time-resolved mode. However, frame missing disappeared, yielding agreement better than 2%, when the dose rate of irradiation (and thus the frame acquisition rates) reached a stable and planned rate as the dose of irradiation was raised past certain thresholds (a minimum 12 s of irradiation per shoot used for SS IMRT). For VMAT, the authors found that dose rate does not affect the frame acquisition rate, thereby causing no frame missing

  18. Portal Vein Thrombosis

    Directory of Open Access Journals (Sweden)

    Hakan Demirci

    2016-01-01

    Full Text Available Portal vein thrombosis is an important cause of presinusoidal portal hypertension. Portal vein thrombosis commonly occurs in patient with cirrhosis, malignancy and prothrombotic states. Patients with acute portal vein thrombosis have immediate onset. Patients with chronic portal vein thrombosis have developed portal hypertension and cavernous portal transformation. Portal vein thrombosis is diagnosed with doppler ultrasound, computed tomography and magnetic resonance imaging. Therapy with low molecular weight heparin achieves recanalization in more than half of acute cases.

  19. Portal manga

    OpenAIRE

    Temprano Hernandez, Joan

    2011-01-01

    El projecte Portal Manga pretén construir una aplicació web que ha de permetre a una empresa anunciar els seus productes a la web, disposar de una botiga virtual en la que es puguin adquirir aquests productes en format digital i finalment un lector web que en permeti la lectura online.

  20. Efficient electron beam deposition for repetitively pulsed krypton fluoride lasers

    International Nuclear Information System (INIS)

    Hegeler, F.; Myers, M.C.; Friedman, M.; Sethian, J.D.; Swanekamp, S.B.; Rose, D.V.; Welch, D.R.

    2002-01-01

    We have demonstrated that we can significantly increase the electron beam transmission efficiency through a pressure foil structure (hibachi) by segmenting the beam into strips to miss the hibachi support ribs. In order to increase the electron beam transmission, the cathode strips are adjusted to compensate for beam rotation and pinching. The beam propagation through the hibachi has been both measured and simulated with 1-D and 3-D codes

  1. Ion collection efficiency of ionization chambers in electron beams

    International Nuclear Information System (INIS)

    Garcia, S.; Cecatti, E.R.

    1984-01-01

    When ionization chambers are used in pulsed radiation beams the high-density of ions produced per pulse permits ion recombination, demanding the use of a correction factor. An experimental technique using the charge collected at two different voltages permits the calculation of the ion collection efficiency. The ion collection efficiency of some common ionization chambers in pulsed electron beams were studied as a function of electron energy, dose rate and depth. Accelerators with magnetic scanning system, in which the instantaneous dose rate is much greater than the average dose rate, present a smaller collection efficiency than accelerators with scattering foil. The results lead to the introduction of a correction factor for ion recombination that is the reciprocal of the ion collection efficiency. It is also suggested a simple technique to connect an external variable DC power supply in a Baldwin Farmer dosemeter. (Author) [pt

  2. Gadgets and Gigawatts - Policies for Energy Efficient Electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-05-13

    By 2010 there will be over 3.5 billion mobile phones subscribers, 2 billion TVs in use around the world and 1 billion personal computers. Electronic devices are a growing part of our lives and many of us can count between 20 and 30 separate items in our homes, from major items like televisions to a host of small gadgets. The communication and entertainment benefits these bring are not only going to people in wealthier nations - in Africa, for example, one in nine people now has a mobile phone. But as these electronic devices gain popularity, they account for a growing portion of household energy consumption. How 'smart' is this equipment from an energy efficiency perspective and should we be concerned about how much energy these gadgets use? What is the potential for energy savings? This new book, Gadgets and Gigawatts: Policies for Energy Efficient Electronics, includes a global assessment of the changing pattern in residential electricity consumption over the past decade and an in-depth analysis of the role played by electronic equipment. It reviews the influence that government policies have had on creating markets for more energy efficient appliances and identifies new opportunities for creating smarter, more energy efficient homes. This book is essential reading for policy makers and others interested in improving the energy efficiency of our homes.

  3. Information Portal Costs and Benefits

    Directory of Open Access Journals (Sweden)

    Lorena BATAGAN

    2006-01-01

    Full Text Available All transformations of our society are the product of the large use of Information and Communications Technologies (ICT and Internet. ICT are technologies which facilitate communication, processing, and transmission of information by electronic means. It is very important to use the new technologies to the correct value because this determinate an increase of global benefits. Portal provides a consistent way to select, evaluate, prioritize and plan the right information. In research we point the important costs and benefits for an informational portal. The portal for local administrative determinate for citizens the access to information of interest and on the other hand make easier for employer to manage the documents.

  4. ELECTRON CYCLOTRON CURRENT DRIVE EFFICIENCY IN GENERAL TOKAMAK GEOMETRY

    International Nuclear Information System (INIS)

    LIN-LUI, Y.R; CHAN, V.S; PRATER, R.

    2003-01-01

    Green's-function techniques are used to calculate electron cyclotron current drive (ECCD) efficiency in general tokamak geometry in the low-collisionality regime. Fully relativistic electron dynamics is employed in the theoretical formulation. The high-velocity collision model is used to model Coulomb collisions and a simplified quasi-linear rf diffusion operator describes wave-particle interactions. The approximate analytic solutions which are benchmarked with a widely used ECCD model, facilitate time-dependent simulations of tokamak operational scenarios using the non-inductive current drive of electron cyclotron waves

  5. Innovative energy efficient low-voltage electron beam emitters

    International Nuclear Information System (INIS)

    Felis, Kenneth P.; Avnery, Tovi; Berejka, Anthony J.

    2002-01-01

    Advanced electron beams (AEB) has developed a modular, low voltage (80-125 keV), high beam current (up to 40 ma), electron emitter with typically 25 cm of beam width, that is housed in an evacuated, returnable chamber that is easy to plug in and connect. The latest in nanofabrication enables AEB to use an ultra-thin beam window. The power supply for AEB's emitter is based on solid-state electronics. This combination of features results in a remarkable electrical efficiency. AEB's electron emitter relies on a touch screen, computer control system. With 80 μm of unit density beam penetration, AEB's electron emitter has gained market acceptance in the curing of opaque, pigmented inks and coatings used on flexible substrates, metals and fiber composites and in the curing of adhesives in foil based laminates

  6. Innovative energy efficient low-voltage electron beam emitters

    Science.gov (United States)

    Felis, Kenneth P.; Avnery, Tovi; Berejka, Anthony J.

    2002-03-01

    Advanced electron beams (AEB) has developed a modular, low voltage (80-125 keV), high beam current (up to 40 ma), electron emitter with typically 25 cm of beam width, that is housed in an evacuated, returnable chamber that is easy to plug in and connect. The latest in nanofabrication enables AEB to use an ultra-thin beam window. The power supply for AEB's emitter is based on solid-state electronics. This combination of features results in a remarkable electrical efficiency. AEB's electron emitter relies on a touch screen, computer control system. With 80 μm of unit density beam penetration, AEB's electron emitter has gained market acceptance in the curing of opaque, pigmented inks and coatings used on flexible substrates, metals and fiber composites and in the curing of adhesives in foil based laminates.

  7. Efficient electronic structure methods applied to metal nanoparticles

    DEFF Research Database (Denmark)

    Larsen, Ask Hjorth

    of efficient approaches to density functional theory and the application of these methods to metal nanoparticles. We describe the formalism and implementation of localized atom-centered basis sets within the projector augmented wave method. Basis sets allow for a dramatic increase in performance compared....... The basis set method is used to study the electronic effects for the contiguous range of clusters up to several hundred atoms. The s-electrons hybridize to form electronic shells consistent with the jellium model, leading to electronic magic numbers for clusters with full shells. Large electronic gaps...... and jumps in Fermi level near magic numbers can lead to alkali-like or halogen-like behaviour when main-group atoms adsorb onto gold clusters. A non-self-consistent NewnsAnderson model is used to more closely study the chemisorption of main-group atoms on magic-number Au clusters. The behaviour at magic...

  8. Four-dimensional dose reconstruction through in vivo phase matching of cine images of electronic portal imaging device.

    Science.gov (United States)

    Yoon, Jihyung; Jung, Jae Won; Kim, Jong Oh; Yi, Byong Yong; Yeo, Inhwan

    2016-07-01

    A method is proposed to reconstruct a four-dimensional (4D) dose distribution using phase matching of measured cine images to precalculated images of electronic portal imaging device (EPID). (1) A phantom, designed to simulate a tumor in lung (a polystyrene block with a 3 cm diameter embedded in cork), was placed on a sinusoidally moving platform with an amplitude of 1 cm and a period of 4 s. Ten-phase 4D computed tomography (CT) images of the phantom were acquired. A planning target volume (PTV) was created by adding a margin of 1 cm around the internal target volume of the tumor. (2) Three beams were designed, which included a static beam, a theoretical dynamic beam, and a planning-optimized dynamic beam (PODB). While the theoretical beam was made by manually programming a simplistic sliding leaf motion, the planning-optimized beam was obtained from treatment planning. From the three beams, three-dimensional (3D) doses on the phantom were calculated; 4D dose was calculated by means of the ten phase images (integrated over phases afterward); serving as "reference" images, phase-specific EPID dose images under the lung phantom were also calculated for each of the ten phases. (3) Cine EPID images were acquired while the beams were irradiated to the moving phantom. (4) Each cine image was phase-matched to a phase-specific CT image at which common irradiation occurred by intercomparing the cine image with the reference images. (5) Each cine image was used to reconstruct dose in the phase-matched CT image, and the reconstructed doses were summed over all phases. (6) The summation was compared with forwardly calculated 4D and 3D dose distributions. Accounting for realistic situations, intratreatment breathing irregularity was simulated by assuming an amplitude of 0.5 cm for the phantom during a portion of breathing trace in which the phase matching could not be performed. Intertreatment breathing irregularity between the time of treatment and the time of planning CT was

  9. Four-dimensional dose reconstruction through in vivo phase matching of cine images of electronic portal imaging device

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jihyung; Jung, Jae Won, E-mail: jungj@ecu.edu [Department of Physics, East Carolina University, Greenville, North Carolina 27858 (United States); Kim, Jong Oh [Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15232 (United States); Yi, Byong Yong [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland 21201 (United States); Yeo, Inhwan [Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, California 92354 (United States)

    2016-07-15

    Purpose: A method is proposed to reconstruct a four-dimensional (4D) dose distribution using phase matching of measured cine images to precalculated images of electronic portal imaging device (EPID). Methods: (1) A phantom, designed to simulate a tumor in lung (a polystyrene block with a 3 cm diameter embedded in cork), was placed on a sinusoidally moving platform with an amplitude of 1 cm and a period of 4 s. Ten-phase 4D computed tomography (CT) images of the phantom were acquired. A planning target volume (PTV) was created by adding a margin of 1 cm around the internal target volume of the tumor. (2) Three beams were designed, which included a static beam, a theoretical dynamic beam, and a planning-optimized dynamic beam (PODB). While the theoretical beam was made by manually programming a simplistic sliding leaf motion, the planning-optimized beam was obtained from treatment planning. From the three beams, three-dimensional (3D) doses on the phantom were calculated; 4D dose was calculated by means of the ten phase images (integrated over phases afterward); serving as “reference” images, phase-specific EPID dose images under the lung phantom were also calculated for each of the ten phases. (3) Cine EPID images were acquired while the beams were irradiated to the moving phantom. (4) Each cine image was phase-matched to a phase-specific CT image at which common irradiation occurred by intercomparing the cine image with the reference images. (5) Each cine image was used to reconstruct dose in the phase-matched CT image, and the reconstructed doses were summed over all phases. (6) The summation was compared with forwardly calculated 4D and 3D dose distributions. Accounting for realistic situations, intratreatment breathing irregularity was simulated by assuming an amplitude of 0.5 cm for the phantom during a portion of breathing trace in which the phase matching could not be performed. Intertreatment breathing irregularity between the time of treatment and the

  10. SU-G-TeP4-03: A Multileaf Collimator Calibration and Quality Assurance Technique Using An Electronic Portal Imaging Device

    Energy Technology Data Exchange (ETDEWEB)

    Lebron, S; Yan, G; Li, J; Lu, B; Liu, C [University of Florida, Gainesville, FL (United States)

    2016-06-15

    Purpose: To develop an accurate and quick multileaf collimator (MLC) calibration and quality assurance technique using an electronic portal imaging device (EPID) Methods: The MLC models used include the MLCi and Agility (Elekta Ltd). This technique consists of two 22(L)x10(W) cm{sup 2} fields with 0{sup 0} and 180{sup 0} collimator angles centered to an offset EPID. The MLC opening is estimated by calculating the profile at the image’s center in the image’s horizontal direction. Scans in the image’s vertical direction were calculated every 20 pixels in the inner 70% of estimated MLC opening. The profiles’ edges were fitted with linear equations to determine the image’s rotation angle. Then, crossline profiles were scanned at the center of each leaf taking into account the leaf’s width at isocenter and the rotation angle. The profiles’ edges determine the location of the leaves’ edges and these were subtracted from the reference leaf’s position in order to determine the relative leaf offsets. The edge location of all profiles was determined by using the parameterized gradient of the penumbra region. The technique was tested against an established diode array-based method, and for different MLC systems, patterns, gantry angles, days, energies, beam modalities and MLC openings. Results: The differences between the proposed and established methods were 0.26±0.19mm. The leaf offsets’ deviation was <0.3mm (5 months period). For pattern fields, the differences between predetermined and calculated offsets were 0.18±0.18mm. The leaf offset deviation of measurements with different energies and MLC openings were <0.1mm and <0.3mm, respectively. The differences between offsets of FF and FFF beams were 0.01±0.02mm (<0.07mm). The differences between the offsets at different gantry angles were 0.08±0.15mm. Conclusion: The proposed method proved to be accurate and efficient in calculating the relative leaf offsets. Parameterized field edge is essential to

  11. Implementing electronic handover: interventions to improve efficiency, safety and sustainability.

    Science.gov (United States)

    Alhamid, Sharifah Munirah; Lee, Desmond Xue-Yuan; Wong, Hei Man; Chuah, Matthew Bingfeng; Wong, Yu Jun; Narasimhalu, Kaavya; Tan, Thuan Tong; Low, Su Ying

    2016-10-01

    Effective handovers are critical for patient care and safety. Electronic handover tools are increasingly used today to provide an effective and standardized platform for information exchange. The implementation of an electronic handover system in tertiary hospitals can be a major challenge. Previous efforts in implementing an electronic handover tool failed due to poor compliance and buy-in from end-users. A new electronic handover tool was developed and incorporated into the existing electronic medical records (EMRs) for medical patients in Singapore General Hospital (SGH). There was poor compliance by on-call doctors in acknowledging electronic handovers, and lack of adherence to safety rules, raising concerns about the safety and efficiency of the electronic handover tool. Urgent measures were needed to ensure its safe and sustained use. A quality improvement group comprising stakeholders, including end-users, developed multi-faceted interventions using rapid PDSA (P-Plan, D-Do, S-Study, A-Act ) cycles to address these issues. Innovative solutions using media and online software provided cost-efficient measures to improve compliance. The percentage of unacknowledged handovers per day was used as the main outcome measure throughout all PDSA cycles. Doctors were also assessed for improvement in their knowledge of safety rules and their perception of the electronic handover tool. An electronic handover tool complementing daily clinical practice can be successfully implemented using solutions devised through close collaboration with end-users supported by the senior leadership. A combined 'bottom-up' and 'top-down' approach with regular process evaluations is crucial for its long-term sustainability. © The Author 2016. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography

    Directory of Open Access Journals (Sweden)

    Njeh Christopher F

    2012-03-01

    Full Text Available Abstract Background The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field. Method A simple quality assurance tool has been designed for rapid and simple test of the light field and radiation field using electronic portal images device (EPID or computed radiography (CR. We tested this QA tool using Varian PortalVision and Elekta iViewGT EPID systems and Kodak CR system. Results Both the single and double exposure techniques were evaluated, with double exposure technique providing a better visualization of the light-radiation field markers. The light and radiation congruency could be detected within 1 mm. This will satisfy the American Association of Physicists in Medicine task group report number 142 recommendation of 2 mm tolerance. Conclusion The QA tool can be used with either an EPID or CR to provide a simple and rapid method to verify light and radiation field congruence.

  13. A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography

    International Nuclear Information System (INIS)

    Njeh, Christopher F; Caroprese, Blas; Desai, Pushkar

    2012-01-01

    The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field. A simple quality assurance tool has been designed for rapid and simple test of the light field and radiation field using electronic portal images device (EPID) or computed radiography (CR). We tested this QA tool using Varian PortalVision and Elekta iViewGT EPID systems and Kodak CR system. Both the single and double exposure techniques were evaluated, with double exposure technique providing a better visualization of the light-radiation field markers. The light and radiation congruency could be detected within 1 mm. This will satisfy the American Association of Physicists in Medicine task group report number 142 recommendation of 2 mm tolerance. The QA tool can be used with either an EPID or CR to provide a simple and rapid method to verify light and radiation field congruence

  14. Electron cyclotron current drive efficiency in an axisymmetric tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Tapia, C.; Beltran-Plata, M. [Instituto Nacional de Investigaciones Nucleares, Dept. de Fisica, Mexico D.F. (Mexico)

    2004-07-01

    The neoclassical transport theory is applied to calculate electron cyclotron current drive (ECCD) efficiency in an axisymmetric tokamak in the low-collisionality regime. The tokamak ordering is used to obtain a system of equations that describe the dynamics of the plasma where the nonlinear ponderomotive (PM) force due to high-power radio-frequency (RF) waves is included. The PM force is produced around an electron cyclotron resonant surface at a specific poloidal location. The ECCD efficiency is analyzed in the cases of first and second harmonics (for different impinging angles of the RF waves) and it is validated using experimental parameter values from TCV and T-10 tokamaks. The results are in agreement with those obtained by means of Green's function techniques. (authors)

  15. High efficiency confinement mode by electron cyclotron heating

    International Nuclear Information System (INIS)

    Funahashi, Akimasa

    1987-01-01

    In the medium size nuclear fusion experiment facility JFT-2M in the Japan Atomic Energy Research Institute, the research on the high efficiency plasma confinement mode has been advanced, and in the experiment in June, 1987, the formation of a high efficiency confinement mode was successfully controlled by electron cyclotron heating, for the first time in the world. This result further advanced the control of the formation of a high efficiency plasma confinement mode and the elucidation of the physical mechanism of that mode, and promoted the research and development of the plasma heating by electron cyclotron heating. In this paper, the recent results of the research on a high efficiency confinement mode at the JFT-2M are reported, and the role of the JFT-2M and the experiment on the improvement of core plasma performance are outlined. Now the plasma temperature exceeding 100 million deg C has been attained in large tokamaks, and in medium size facilities, the various measures for improving confinement performance are to be brought forth and their scientific basis is elucidated to assist large facilities. The JFT-2M started the operation in April, 1983, and has accumulated the results smoothly since then. (Kako, I.)

  16. The provider perspective: investigating the effect of the Electronic Patient-Reported Outcome (ePRO) mobile application and portal on primary care provider workflow.

    Science.gov (United States)

    Hans, Parminder K; Gray, Carolyn Steele; Gill, Ashlinder; Tiessen, James

    2018-03-01

    Aim This qualitative study investigates how the Electronic Patient-Reported Outcome (ePRO) mobile application and portal system, designed to capture patient-reported measures to support self-management, affected primary care provider workflows. The Canadian health system is facing an ageing population that is living with chronic disease. Disruptive innovations like mobile health technologies can help to support health system transformation needed to better meet the multifaceted needs of the complex care patient. However, there are challenges with implementing these technologies in primary care settings, in particular the effect on primary care provider workflows. Over a six-week period interdisciplinary primary care providers (n=6) and their complex care patients (n=12), used the ePRO mobile application and portal to collaboratively goal-set, manage care plans, and support self-management using patient-reported measures. Secondary thematic analysis of focus groups, training sessions, and issue tracker reports captured user experiences at a Toronto area Family Health Team from October 2014 to January 2015. Findings Key issues raised by providers included: liability concerns associated with remote monitoring, increased documentation activities due to a lack of interoperability between the app and the electronic patient record, increased provider anxiety with regard to the potential for the app to disrupt and infringe upon appointment time, and increased demands for patient engagement. Primary care providers reported the app helped to focus care plans and to begin a collaborative conversation on goal-setting. However, throughout our investigation we found a high level of provider resistance evidenced by consistent attempts to shift the app towards fitting with existing workflows rather than adapting much of their behaviour. As health systems seek innovative and disruptive models to better serve this complex patient population, provider change resistance will need to

  17. High efficiency, multiterawatt x-ray free electron lasers

    Directory of Open Access Journals (Sweden)

    C. Emma

    2016-02-01

    Full Text Available In this paper we present undulator magnet tapering methods for obtaining high efficiency and multiterawatt peak powers in x-ray free electron lasers (XFELs, a key requirement for enabling 3D atomic resolution single molecule imaging and nonlinear x-ray science. The peak power and efficiency of tapered XFELs is sensitive to time dependent effects, like synchrotron sideband growth. To analyze this dependence in detail we perform a comparative numerical optimization for the undulator magnetic field tapering profile including and intentionally disabling these effects. We show that the solution for the magnetic field taper profile obtained from time independent optimization does not yield the highest extraction efficiency when time dependent effects are included. Our comparative optimization is performed for a novel undulator designed specifically to obtain TW power x-ray pulses in the shortest distance: superconducting, helical, with short period and built-in strong focusing. This design reduces the length of the breaks between modules, decreasing diffraction effects, and allows using a stronger transverse electron focusing. Both effects reduce the gain length and the overall undulator length. We determine that after a fully time dependent optimization of a 100 m long Linac coherent light source-like XFEL we can obtain a maximum efficiency of 7%, corresponding to 3.7 TW peak radiation power. Possible methods to suppress the synchrotron sidebands, and further enhance the FEL peak power, up to about 6 TW by increasing the seed power and reducing the electron beam energy spread, are also discussed.

  18. Web-based Service Portal in Healthcare

    Science.gov (United States)

    Silhavy, Petr; Silhavy, Radek; Prokopova, Zdenka

    Information delivery is one the most important task in healthcare. The growing sector of electronic healthcare has an important impact on the information delivery. There are two basic approaches towards information delivering. The first is web portal and second is touch-screen terminal. The aim of this paper is to investigate the web-based service portal. The most important advantage of web-based portal in the field of healthcare is an independent access for patients. This paper deals with the conditions and frameworks for healthcare portals

  19. High efficiency inductive output tubes with intense annular electron beams

    Science.gov (United States)

    Appanam Karakkad, J.; Matthew, D.; Ray, R.; Beaudoin, B. L.; Narayan, A.; Nusinovich, G. S.; Ting, A.; Antonsen, T. M.

    2017-10-01

    For mobile ionospheric heaters, it is necessary to develop highly efficient RF sources capable of delivering radiation in the frequency range from 3 to 10 MHz with an average power at a megawatt level. A promising source, which is capable of offering these parameters, is a grid-less version of the inductive output tube (IOT), also known as a klystrode. In this paper, studies analyzing the efficiency of grid-less IOTs are described. The basic trade-offs needed to reach high efficiency are investigated. In particular, the trade-off between the peak current and the duration of the current micro-pulse is analyzed. A particle in the cell code is used to self-consistently calculate the distribution in axial and transverse momentum and in total electron energy from the cathode to the collector. The efficiency of IOTs with collectors of various configurations is examined. It is shown that the efficiency of IOTs can be in the 90% range even without using depressed collectors.

  20. Investigation of Heat Sink Efficiency for Electronic Component Cooling Applications

    DEFF Research Database (Denmark)

    Staliulionis, Ž.; Zhang, Zhe; Pittini, Riccardo

    2014-01-01

    Research and optimisation of cooling of electronic components using heat sinks becomes increasingly important in modern industry. Numerical methods with experimental real-world verification are the main tools to evaluate efficiency of heat sinks or heat sink systems. Here the investigation...... of relatively simple heat sink application is performed using modeling based on finite element method, and also the potential of such analysis was demonstrated by real-world measurements and comparing obtained results. Thermal modeling was accomplished using finite element analysis software COMSOL and thermo...

  1. Efficient Injection of Electron Beams into Magnetic Guide Fields

    International Nuclear Information System (INIS)

    Chorny, V.; Cooperstein, G.; Dubyna, V.; Frolov, O.; Harper-Slaboszewicz, V.; Hinshelwood, D.; Schneider, R.; Solovyov, V.; Tsepilov, H.; Vitkovitsky, I.; Ware, K.

    1999-01-01

    Preliminary experimental and modeling study of injection and transport of high current electron beams in current-neutralized background gas has been performed. Initial analysis of the results indicates that high current triaxial ring diode operates very reproducibly in the pinch mode. High current density beam can be injected efficiently into the drift region, using azimuthal guide field with reduced intensity near the injection region. This was shown to improve the effectiveness of capturing the beam for the transport. The transport length was insufficient to measure losses, such as would arise from scattering with the background gas

  2. Noncirrotisk intrahepatisk portal hypertension

    DEFF Research Database (Denmark)

    Dam Fialla, Annette; Havelund, Troels

    2007-01-01

    Non-cirrhotic intrahepatic portal hypertension is characterized by portal hypertension in the absence of liver cirrhosis or portal vein thrombosis. The disease is common in the East and rarely seen in the West. Two cases with oesophageal varices are described. The histopathology is heterogeneous...... but includes vascular lesions and portal fibrosis. Patient management follows the current recommendations for variceal bleeding....

  3. Efficiency enhancement of a harmonic lasing free-electron laser

    International Nuclear Information System (INIS)

    Salehi, E.; Maraghechi, B.; Mirian, N. S.

    2015-01-01

    The harmonic lasing free-electron laser amplifier, in which two wigglers is employed in order for the fundamental resonance of the second wiggler to coincide with the third harmonic of the first wiggler to generate ultraviolet radiation, is studied. A set of coupled nonlinear first-order differential equations describing the nonlinear evolution of the system, for a long electron bunch, is solved numerically by CYRUS code. Solutions for the non-averaged and averaged equations are compared. Remarkable agreement is found between the averaged and non-averaged simulations for the evolution of the third harmonic. Thermal effects in the form of longitudinal velocity spread are also investigated. For efficiency enhancement, the second wiggler field is set to decrease linearly and nonlinearly at the point where the radiation of the third harmonic saturates. The optimum starting point and the slope of the tapering of the amplitude of the wiggler are found by a successive run of the code. It is found that tapering can increase the saturated power of the third harmonic considerably. In order to reduce the length of the wiggler, the prebunched electron beam is considered

  4. Efficiency enhancement of a harmonic lasing free-electron laser

    Science.gov (United States)

    Salehi, E.; Maraghechi, B.; Mirian, N. S.

    2015-03-01

    The harmonic lasing free-electron laser amplifier, in which two wigglers is employed in order for the fundamental resonance of the second wiggler to coincide with the third harmonic of the first wiggler to generate ultraviolet radiation, is studied. A set of coupled nonlinear first-order differential equations describing the nonlinear evolution of the system, for a long electron bunch, is solved numerically by CYRUS code. Solutions for the non-averaged and averaged equations are compared. Remarkable agreement is found between the averaged and non-averaged simulations for the evolution of the third harmonic. Thermal effects in the form of longitudinal velocity spread are also investigated. For efficiency enhancement, the second wiggler field is set to decrease linearly and nonlinearly at the point where the radiation of the third harmonic saturates. The optimum starting point and the slope of the tapering of the amplitude of the wiggler are found by a successive run of the code. It is found that tapering can increase the saturated power of the third harmonic considerably. In order to reduce the length of the wiggler, the prebunched electron beam is considered.

  5. Efficiency enhancement of a harmonic lasing free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Salehi, E.; Maraghechi, B., E-mail: behrouz@aut.ac.ir [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of); Mirian, N. S. [School of Particle and Accelerator Physics, Institute for Research in Fundamental Sciences (IPM), 19395-5531 Tehran (Iran, Islamic Republic of)

    2015-03-15

    The harmonic lasing free-electron laser amplifier, in which two wigglers is employed in order for the fundamental resonance of the second wiggler to coincide with the third harmonic of the first wiggler to generate ultraviolet radiation, is studied. A set of coupled nonlinear first-order differential equations describing the nonlinear evolution of the system, for a long electron bunch, is solved numerically by CYRUS code. Solutions for the non-averaged and averaged equations are compared. Remarkable agreement is found between the averaged and non-averaged simulations for the evolution of the third harmonic. Thermal effects in the form of longitudinal velocity spread are also investigated. For efficiency enhancement, the second wiggler field is set to decrease linearly and nonlinearly at the point where the radiation of the third harmonic saturates. The optimum starting point and the slope of the tapering of the amplitude of the wiggler are found by a successive run of the code. It is found that tapering can increase the saturated power of the third harmonic considerably. In order to reduce the length of the wiggler, the prebunched electron beam is considered.

  6. A comparison of field-only electronic portal imaging hard copies with double exposure port films in radiation therapy treatment setup confirmation to determine its clinical application in a radiotherapy center

    International Nuclear Information System (INIS)

    Hatherly, Kay; Smylie, Josephine; Rodger, Alan

    1999-01-01

    Purpose: To determine in which treatment sites field-only hard copy electronic portal images (EPI) captured during a treatment exposure could replace traditional double exposed port films in a busy radiation oncology department. Methods and Materials: The three linear accelerators in the William Buckland Radiotherapy Centre (WBRC) at the Alfred Hospital in Melbourne are each equipped with an electronic portal imaging device (EPID). These devices can be used daily on all patients where the treatment fields are within the size constraint of the cassette, for example, less than 25 x 25 cm. Port films using radiographic film in hard cassettes were previously considered the standard method of field placement verification. After the radiation therapists were trained in all program aspects of capturing, enhancing, and producing hard copies of EPIs, a study was developed to evaluate the possibility of replacing port films with EPI hard copies within the established departmental procedures. Comparison of EPI hard copy with the simulator film and the port film of the same field was carried out by the radiation oncologist specialists. Seventy-eight comparison sets were generated and grouped into seven anatomical regions for evaluation by the radiation oncologist specialist responsible for each particular region. The outcome decision was the preferred imaging option. Where no preference was stated, EPI became the modality of choice, as it increased the efficiency of work practice. Results: The results indicate that field-only EPI can be considered to be at least as clinically useful for treatment verification in the following sites: breast, chest, hip, spine, and large pelvic fields. Port films using a standard, double exposure technique were considered necessary for partial brain fields, small pelvis fields, extremities, and radical head and neck fields. Conclusion: The quality of field-only images captured using an EPID has been favorably assessed to be equivalent to, or an

  7. An automated portal verification system for the tangential breast portal field

    International Nuclear Information System (INIS)

    Yin, F.-F.; Lai, W.; Chen, C. W.; Nelson, D. F.

    1995-01-01

    Purpose/Objective: In order to ensure the treatment is delivered as planned, a portal image is acquired in the accelerator and is compared to the reference image. At present, this comparison is performed by radiation oncologists based on the manually-identified features, which is both time-consuming and potentially error-prone. With the introduction of various electronic portal imaging devices, real-time patient positioning correction is becoming clinically feasible to replace time-delayed analysis using films. However, this procedure requires present of radiation oncologists during patient treatment which is not cost-effective and practically not realistic. Therefore, the efficiency and quality of radiation therapy could be substantially improved if this procedure can be automated. The purpose of this study is to develop a fully computerized verification system for the radiation therapy of breast cancer for which a similar treatment setup is generally employed. Materials/Methods: The automated verification system involves image acquisition, image feature extraction, feature correlation between reference and portal images, and quantitative evaluation of patient setup. In this study, a matrix liquid ion-chamber EPID was used to acquire digital portal images which is directly attached to Varian CL2100C accelerator. For effective use of computation memory, the 12-bit gray levels in original portal images were quantized to form a range of 8-bit gray levels. A typical breast portal image includes three important components: breast and lung tissues in the treatment field, air space within the treatment field, and non-irradiated region. A hierarchical region processing technique was developed to separate these regions sequentially. The inherent hierarchical features were formulated based on different radiation attenuation for different regions as: treatment field edge -- breast skin line -- chest wall. Initially, a combination of a Canny edge detector and a constrained

  8. Assessment of three-dimensional set-up errors in conventional head and neck radiotherapy using electronic portal imaging device

    International Nuclear Information System (INIS)

    Gupta, Tejpal; Chopra, Supriya; Kadam, Avinash; Agarwal, Jai Prakash; Devi, P Reena; Ghosh-Laskar, Sarbani; Dinshaw, Ketayun Ardeshir

    2007-01-01

    Set-up errors are an inherent part of radiation treatment process. Coverage of target volume is a direct function of set-up margins, which should be optimized to prevent inadvertent irradiation of adjacent normal tissues. The aim of this study was to evaluate three-dimensional (3D) set-up errors and propose optimum margins for target volume coverage in head and neck radiotherapy. The dataset consisted of 93 pairs of orthogonal simulator and corresponding portal images on which 558 point positions were measured to calculate translational displacement in 25 patients undergoing conventional head and neck radiotherapy with antero-lateral wedge pair technique. Mean displacements, population systematic (Σ) and random (σ) errors and 3D vector of displacement was calculated. Set-up margins were calculated using published margin recipes. The mean displacement in antero-posterior (AP), medio-lateral (ML) and supero-inferior (SI) direction was -0.25 mm (-6.50 to +7.70 mm), -0.48 mm (-5.50 to +7.80 mm) and +0.45 mm (-7.30 to +7.40 mm) respectively. Ninety three percent of the displacements were within 5 mm in all three cardinal directions. Population systematic (Σ) and random errors (σ) were 0.96, 0.98 and 1.20 mm and 1.94, 1.97 and 2.48 mm in AP, ML and SI direction respectively. The mean 3D vector of displacement was 3.84 cm. Using van Herk's formula, the clinical target volume to planning target volume margins were 3.76, 3.83 and 4.74 mm in AP, ML and SI direction respectively. The present study report compares well with published set-up error data relevant to head and neck radiotherapy practice. The set-up margins were <5 mm in all directions. Caution is warranted against adopting generic margin recipes as different margin generating recipes lead to a different probability of target volume coverage

  9. Power Electronics as Efficient Interface of Renewable Energy Sources

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe; Kjær, Søren Bækhøj

    2004-01-01

    The global electrical energy consumption is steadily rising and consequently there is a demand to increase the power generation capacity. A significant percentage of the required capacity increase can be based on renewable energy sources. Wind turbine technology, as the most cost effective...... renewable energy conversion system, will play an important part in our future energy supply. But other sources like microturbines, photovoltaics and fuel cell systems may also be serious contributor to the power supply. Characteristically, power electronics will be an efficient and important interface...... to the grid and this paper will first briefly discuss three different alternative/ renewable energy sources. Next, various configurations of the wind turbine technology are presented, as this technology seems to be most developed and cost-effective. Finally, the developments and requirements from the grid...

  10. Idiopathic portal hypertension

    International Nuclear Information System (INIS)

    Han, Tae Kyun; Ryu, Dae Sik; Kim, Heung Chul; Hur, Hun; Eom, Kyeung Tae; Namkung, Sook; Park, Man Soo; Hwang, Woo Chul; Lee, Kwan Seop

    1996-01-01

    To describe the radiologic findings of idiopathic portal hypertension and to find the points of differentiation between idiopathic portal hypertension and liver cirrhosis. Four portograms in five patients who for four years had suffered from pathologically confirmed idiopathic portal hypertension were retrospectively analyzed and compared with a portogram obtained from a control subject with liver cirrhosis. Portographic finding s of idiopathic portal hypertension were paucity of medium-sized portal branches, irregular and obtuse-angled division of peripheral branches, abrupt interruption and an avascular area beneath the liver margin. A portogram of idiopathic portal hypertension may be useful in differentiation this and liver cirrhosis

  11. Rare Disease Video Portal

    OpenAIRE

    Sánchez Bocanegra, Carlos Luis

    2011-01-01

    Rare Disease Video Portal (RD Video) is a portal web where contains videos from Youtube including all details from 12 channels of Youtube. Rare Disease Video Portal (RD Video) es un portal web que contiene los vídeos de Youtube incluyendo todos los detalles de 12 canales de Youtube. Rare Disease Video Portal (RD Video) és un portal web que conté els vídeos de Youtube i que inclou tots els detalls de 12 Canals de Youtube.

  12. Effect of resonant-to-bulk electron momentum transfer on the efficiency of electron-cyclotron current-drive

    International Nuclear Information System (INIS)

    Matsuda, Y.; Smith, G.R.; Cohen, R.H.

    1989-01-01

    Efficiency of current drive by electron cyclotron waves is investigated numerically by a bounce-averaged Fokker-Planck code to ellucidate the effects of momentum transfer from resonant to bulk-electrons, finite bulk temperature relative to the energy of resonant electrons, and trapped electrons. Comparisons are made with existing theories to assess their validity and quantitative difference between theory and code results. Difference of nearly a factor of 2 was found in efficiency between some theory and code results. (author)

  13. Electronic medical records and efficiency and productivity during office visits.

    Science.gov (United States)

    Furukawa, Michael F

    2011-04-01

    To estimate the relationship between electronic medical record (EMR) use and efficiency of utilization and provider productivity during visits to US office-based physicians. Cross-sectional analysis of the 2006-2007 National Ambulatory Medical Care Survey. The sample included 62,710 patient visits to 2625 physicians. EMR systems included demographics, clinical notes, prescription orders, and laboratory and imaging results. Efficiency was measured as utilization of examinations, laboratory tests, radiology procedures, health education, nonmedication treatments, and medications. Productivity was measured as total services provided per 20-minute period. Survey-weighted regressions estimated association of EMR use with services provided, visit intensity/duration, and productivity. Marginal effects were estimated by averaging across all visits and by major reason for visit. EMR use was associated with higher probability of any examination (7.7%, 95% confidence interval [CI] = 2.4%, 13.1%); any laboratory test (5.7%, 95% CI = 2.6%, 8.8%); any health education (4.9%, 95% CI = 0.2%, 9.6%); and fewer laboratory tests (-7.1%, 95% CI = -14.2%, -0.1%). During pre/post surgery visits, EMR use was associated with 7.3% (95% CI= -12.9%, -1.8%) fewer radiology procedures. EMR use was not associated with utilization of nonmedication treatments and medications, or visit duration. During routine visits for a chronic problem, EMR use was associated with 11.2% (95% CI = 5.7%, 16.8%) more diagnostic/screening services provided per 20-minute period. EMR use had a mixed association with efficiency and productivity during office visits. EMRs may improve provider productivity, especially during visits for a new problem and routine chronic care.

  14. Design and implementation of a web-based patient portal linked to an electronic health record designed to improve medication safety: the Patient Gateway medications module

    Directory of Open Access Journals (Sweden)

    Jeffrey Schnipper

    2008-07-01

    Full Text Available In this article we describe the background, design, and preliminary results of a medications module within Patient Gateway (PG, a patient portal linked to an electronic health record (EHR. The medications module is designed to improve the accuracy of medication lists within the EHR, reduce adverse drug events and improve patient_provider communication regarding medications and allergies in several primary care practices within a large integrated healthcare delivery network. This module allows patients to view and modify the list of medications and allergies from the EHR, report nonadherence, side effects and other medication-related problems and easily communicate this information to providers, who can verify the information and update the EHR as needed. Usage and satisfaction data indicate that patients found the module easy to use, felt that it led to their providers having more accurate information about them and enabled them to feel more prepared for their forthcoming visits. Further analyses will determine the effects of this module on important medication-related outcomes and identify further enhancements needed to improve on this approach.

  15. Efficient temporal shaping of electron distributions for high-brightness photoemission electron guns

    Directory of Open Access Journals (Sweden)

    Ivan V. Bazarov

    2008-04-01

    Full Text Available To achieve the lowest emittance electron bunches from photoemission electron guns, it is essential to limit the uncorrelated emittance growth due to space charge forces acting on the bunch in the vicinity of the photocathode through appropriate temporal shaping of the optical pulses illuminating the photocathode. We present measurements of the temporal profile of electron bunches from a bulk crystal GaAs photocathode illuminated with 520 nm wavelength pulses from a frequency-doubled Yb-fiber laser. A transverse deflecting rf cavity was used to make these measurements. The measured laser pulse temporal profile and the corresponding electron beam temporal profile have about 30 ps FWHM duration, with rise and fall times of a few ps. GaAs illuminated by 520 nm optical pulses is a prompt emitter within our measurement uncertainty of ∼1  ps rms. Combined with the low thermal emittance of negative electron affinity photocathodes, GaAs is a very suitable photocathode for high-brightness photoinjectors. We also report measurements of the photoemission response time for GaAsP, which show a strong dependence on the quantum efficiency of the photocathode.

  16. The Knowledge Portal

    Data.gov (United States)

    Office of Personnel Management — Information on various courses, as well as personal data of employees and training records from The Knowledge Portal (TKP), a web-based training portal used for the...

  17. Improving efficiency and reducing administrative burden through electronic communication.

    Science.gov (United States)

    Cook, Katlyn E; Ludens, Gail M; Ghosh, Amit K; Mundell, William C; Fleming, Kevin C; Majka, Andrew J

    2013-01-01

    The InBox messaging system is an internal, electronic program used at Mayo Clinic, Rochester, MN, to facilitate the sending, receiving, and answering of patient-specific messages and alerts. A standardized InBox was implemented in the Division of General Internal Medicine to decrease the time physicians, physician assistants, and nurse practitioners (clinicians) spend on administrative tasks and to increase efficiency. Clinicians completed surveys and a preintervention InBox pilot test to determine inefficiencies related to administrative burdens and defects (message entry errors). Results were analyzed using Pareto diagrams, value stream mapping, and root cause analysis to prioritize administrative-burden inefficiencies to develop a new, standardized InBox. Clinicians and allied health staff were the target of this intervention and received standardized InBox training followed by a postintervention pilot test for clinicians. Sixteen of 28 individuals (57%) completed the preintervention survey. Twenty-eight clinicians participated in 2 separate 8-day pilot tests (before and after intervention) for the standardized InBox. The number of InBox defects was substantially reduced from 37 (Pilot 1) to 7 (Pilot 2). Frequent InBox defects decreased from 25% to 10%. More than half of clinicians believed the standardized InBox positively affected their work, and 100% of clinicians reported no negative affect on their work. This project demonstrated the successful implementation of the standardized InBox messaging system. Initial assessments show substantial reduction of InBox entry defects and administrative tasks completed by clinicians. The findings of this project suggest increased clinician and allied health staff efficiency, satisfaction, improved clinician work-life balance, and decreased clinician burden caused by administrative tasks.

  18. Usability of Discovery Portals

    NARCIS (Netherlands)

    Bulens, J.D.; Vullings, L.A.E.; Houtkamp, J.M.; Vanmeulebrouk, B.

    2013-01-01

    As INSPIRE progresses to be implemented in the EU, many new discovery portals are built to facilitate finding spatial data. Currently the structure of the discovery portals is determined by the way spatial data experts like to work. However, we argue that the main target group for discovery portals

  19. Portals people, processes, technology

    CERN Document Server

    Cox, Andrew

    2006-01-01

    First applied to internet gateways such as Yahoo, the concept of the ""portal"" has evolved in a number of directions. How can information services best take advantage of internet portals to improve access to resources? This collection seeks answers to such questions, providing an overview of how portals are being used.

  20. Efficient electron heating in relativistic shocks and gamma-ray-burst afterglow.

    Science.gov (United States)

    Gedalin, M; Balikhin, M A; Eichler, D

    2008-02-01

    Electrons in shocks are efficiently energized due to the cross-shock potential, which develops because of differential deflection of electrons and ions by the magnetic field in the shock front. The electron energization is necessarily accompanied by scattering and thermalization. The mechanism is efficient in both magnetized and nonmagnetized relativistic electron-ion shocks. It is proposed that the synchrotron emission from the heated electrons in a layer of strongly enhanced magnetic field is responsible for gamma-ray-burst afterglows.

  1. Energy efficient hotspot-targeted embedded liquid cooling of electronics

    International Nuclear Information System (INIS)

    Sharma, Chander Shekhar; Tiwari, Manish K.; Zimmermann, Severin; Brunschwiler, Thomas; Schlottig, Gerd; Michel, Bruno; Poulikakos, Dimos

    2015-01-01

    Highlights: • We present a novel concept for hotspot-targeted, energy efficient ELC for electronic chips. • Microchannel throttling zones distribute flow optimally without any external control. • Design is optimized for highly non-uniform multicore chip heat flux maps. • Optimized design minimizes chip temperature non-uniformity. • This is achieved with pumping power consumption less than 1% of total chip power. - Abstract: Large data centers today already account for nearly 1.31% of total electricity consumption with cooling responsible for roughly 33% of that energy consumption. This energy intensive cooling problem is exacerbated by the presence of hotspots in multicore microprocessors due to excess coolant flow requirement for thermal management. Here we present a novel liquid-cooling concept, for targeted, energy efficient cooling of hotspots through passively optimized microchannel structures etched into the backside of a chip (embedded liquid cooling or ELC architecture). We adopt an experimentally validated and computationally efficient modeling approach to predict the performance of our hotspot-targeted ELC design. The design is optimized for exemplar non-uniform chip power maps using Response Surface Methodology (RSM). For industrially acceptable limits of approximately 0.4 bar (40 kPa) on pressure drop and one percent of total chip power on pumping power, the optimized designs are computationally evaluated against a base, standard ELC design with uniform channel widths and uniform flow distribution. For an average steady-state heat flux of 150 W/cm 2 in core areas (hotspots) and 20 W/cm 2 over remaining chip area (background), the optimized design reduces the maximum chip temperature non-uniformity by 61% to 3.7 °C. For a higher average, steady-state hotspot heat flux of 300 W/cm 2 , the maximum temperature non-uniformity is reduced by 54% to 8.7 °C. It is shown that the base design requires a prohibitively high level of pumping power (about

  2. Efficient evaluation of atom tunneling combined with electronic structure calculations.

    Science.gov (United States)

    Ásgeirsson, Vilhjálmur; Arnaldsson, Andri; Jónsson, Hannes

    2018-03-14

    Methodology for finding optimal tunneling paths and evaluating tunneling rates for atomic rearrangements is described. First, an optimal JWKB tunneling path for a system with fixed energy is obtained using a line integral extension of the nudged elastic band method. Then, a calculation of the dynamics along the path is used to determine the temperature at which it corresponds to an optimal Feynman path for thermally activated tunneling (instanton) and a harmonic approximation is used to estimate the transition rate. The method is illustrated with calculations for a modified two-dimensional Müller-Brown surface but is efficient enough to be used in combination with electronic structure calculations of the energy and atomic forces in systems containing many atoms. An example is presented where tunneling is the dominant mechanism well above room temperature as an H 3 BNH 3 molecule dissociates to form H 2 . Also, a solid-state example is presented where density functional theory calculations of H atom tunneling in a Ta crystal give close agreement with experimental measurements on hydrogen diffusion over a wide range in temperature.

  3. A Semantically Enabled Portal for Facilitating the Public Service Provision

    Science.gov (United States)

    Loutas, Nikolaos; Giantsiou, Lemonia; Peristeras, Vassilios; Tarabanis, Konstantinos

    During the past years, governments have made significant efforts to improve both their internal processes and the services that they provide to citizens and businesses. These led to several successful e-Government applications (e.g., see www.epractice.eu). One of the most popular tools that was used by governments in order to modernize their services and make them accessible is e-Government portals, e.g., (Drigas et al. 2005), (Fang 2002). The main goals of such portals are: To make available complete, easy to understand, and structured information about public services and public administration's modus operandi, which will assist citizens during the service provision process. To facilitate the electronic execution of public services. Nevertheless, most of such efforts did not succeed. Gartner argues that most e-Government strategies have not achieved their objectives and have failed to trigger sustainable government transformation to greater efficiency and citizen-centricity (DiMaio 2007).

  4. Evaluation of an edge method for computed radiography and an electronic portal imaging device in radiotherapy: image quality measurements

    Energy Technology Data Exchange (ETDEWEB)

    Son, Soon-Yong [Asan Medical Center, Seoul (Korea, Republic of); Choe, Bo-Young [The Catholic University of Korea, Seoul (Korea, Republic of); Lee, Jeong-Woo [Konkuk University Hospital, Seoul (Korea, Republic of); Kim, Jung-Min [Korea University, Seoul (Korea, Republic of); Jeong, Hoi-Woun [The Baekseok Culture University College of Korea, Cheon-an (Korea, Republic of); Kim, Ham-Gyum; Kim, Wha-Sun [The Ansan University College of Korea, Ansan (Korea, Republic of); Lyu, Kwang-Yeul; Min, Jung-Whan [The Shingu University College of Korea, Seongnam (Korea, Republic of); Kim, Ki-Won [Samsung Medical Center, Seoul (Korea, Republic of)

    2014-12-15

    Regular quality assurance (QA) of image quality is essential for reasonable patient dose and accurate treatment. Thus, QA should be performed as a routine for correction. The purpose of this study was to evaluate the modulation transfer function (MTF), the noise power spectrum (NPS) and the detective quantum efficiency (DQE) of the computed radiography (CR) system and the digital radiography (DR) system by using the edge method in megavoltage X-ray imaging (MVI). We used an edge block, which consisting of tungsten with dimensions of 19 (thickness) x 10 (length) x 1 (width) cm{sup 3} and measured the pre-sampling MTF by using a 6-megavolt (MV) energy. Computed radiography with an image plate (CR-IP) showed the values of 0.4 mm{sup -1} and 1.19 mm{sup -1} for MTF 0.5 and 0.1. In the DR group, Elekta iViewGT showed the highest value of 0.27 mm{sup -1} for MTF 0.5, and Siemens BEAMVIEW{sup PLUS} showed the highest value of 0.98 mm{sup -1} for MTF 0.1. In CR, the NPS of CR-IP showed a favorable noise distribution. Thus, in the DR group, the NPS of Elekta iViewGT showed the highest noise distribution. CR-IP showed values at peak DQE and 1 mm{sup -1} DQE of 0.0013 and 0.00011, respectively. In the DR group, Elekta iViewGT showed the best efficiency at a peak DQE of 0.0009, and Siemens BEAMVIEW{sup PLUS} showed the best efficiency at a 1-mm{sup -1} DQE of 0.000008. The edge method produced fast assessments of the MTF and the DQE. We could validate the evaluation of the edge method by comparing of the CR system to the DR system. This study demonstrated that the edge method can be used for not only traditional QA imaging but also quantitative MTF, NPS and DQE measurements in detector development.

  5. Fundamental factors influencing portal image quality

    International Nuclear Information System (INIS)

    Jaffray, D.A.

    1995-01-01

    It has been recognized that improved methods of verifying radiation field placement in external beam radiotherapy are required in order to make frequent checks of field placement feasible. As a result, a large number of electronic portal imaging systems have been developed as possible replacements for film. These developments have produced digital systems with faster acquisition and improved display contrast, however, the quality of the images acquired with such systems is still disappointing. This presentation examines many of the fundamental factors which limit the quality of radiographs obtained with a megavoltage radiotherapy beam. The size and shape of the radiation sources (focal and extra-focal) in radiotherapy machines and their influence on the spatial resolution of portal images are examined. Monte Carlo simulations of x-ray interactions within the patient determined that a significant fraction of the x-ray scatter generated in the patient is due to bremsstrahlung and positron annihilation. Depending on the detector, the scatter signal can reduce the differential signal-to-noise by 20%. Furthermore, a Monte Carlo study of the interaction of x-rays within typical fluoroscopic imaging detectors (metal plate/phosphor screen) demonstrates the degrading effect of energy absorption noise on the detective quantum efficiency of fluoroscopic based imaging systems. Finally, the spatial frequency content in the x-ray shadowgram is demonstrated to change with x-ray energy, resulting in images that appear to have reduced spatial resolution at megavoltage energies. The relative magnitude of each of these factors will be presented and recommendations for the next generation of portal imaging systems will be made

  6. Portal hypertensiv gastropati

    DEFF Research Database (Denmark)

    Brinch, K; Møller, S; Henriksen, Jens Henrik Sahl

    1995-01-01

    Portal hypertensive gastropathy (PHG) as defined by congestive changes in the gastric mucosa owing to increased portal pressure, was first described about ten years ago. Whereas definition and grading of severity are still under debate, there is general agreement that PHG is a new clinical entity....... PHG is present in 50-80% of patients with liver cirrhosis. PHG is a major cause of upper gastrointestinal bleeding in patients with portal hypertension (25-90% depending on severity). Presence of portal hypertension is a prerequisite for the development of PHG, and reduction of portal pressure...

  7. Mobile Portal Implementation Strategy

    DEFF Research Database (Denmark)

    Gao, Ping; Damsgaard, Jan

    2005-01-01

    Mobile portal plays an important role in mobile commerce market. Current literature focuses on static analysis on the value chain of mobile portals. This article provides a dynamic perspective on mobile portal strategy. Drawing upon network economics, we describe mobile portal implementation...... as a fourphase process. In different phase, a portal provider has various challenges to overcome and adopt diverse strategies, and correspondingly the regulator has different foci. The conceptual framework proposed in this article offers a basis for further analyses on the market dynamics of mobile commerce......, and can be generalized to studying other networked technologies...

  8. New ICPP portal monitor

    International Nuclear Information System (INIS)

    Georgeson, M.A.; Nichols, C.E.

    1981-04-01

    A large area gas filled proportional-detector portal monitor mounted in a swinging door frame has been designed and developed at the Idaho Chemical Processing Plant (ICPP). This monitor extends the sensitivity and speed of personnel contamination detection to levels equal to or exceeding that obtained using hand-held portable survey techniques. The new monitor has state-of-the-art electronics which result in rapid response, and use statistical principles in the alarm logic to reduce or eliminate spurious alarms. In addition, the evaluation of this instrument indicates that it will detect small enough quantities of U-235 in shielded containers to meet current special nuclear materials (SNM) detection standards. Simultaneous detection of very low level contamination and small quantities of SNM results in a monitor particularly useful for nuclear installations

  9. A novel method for patient exit and entrance dose prediction based on water equivalent path length measured with an amorphous silicon electronic portal imaging device

    Science.gov (United States)

    Kavuma, Awusi; Glegg, Martin; Metwaly, Mohamed; Currie, Garry; Elliott, Alex

    2010-01-01

    In vivo dosimetry is one of the quality assurance tools used in radiotherapy to monitor the dose delivered to the patient. Electronic portal imaging device (EPID) images for a set of solid water phantoms of varying thicknesses were acquired and the data fitted onto a quadratic equation, which relates the reduction in photon beam intensity to the attenuation coefficient and material thickness at a reference condition. The quadratic model is used to convert the measured grey scale value into water equivalent path length (EPL) at each pixel for any material imaged by the detector. For any other non-reference conditions, scatter, field size and MU variation effects on the image were corrected by relative measurements using an ionization chamber and an EPID. The 2D EPL is linked to the percentage exit dose table, for different thicknesses and field sizes, thereby converting the plane pixel values at each point into a 2D dose map. The off-axis ratio is corrected using envelope and boundary profiles generated from the treatment planning system (TPS). The method requires field size, monitor unit and source-to-surface distance (SSD) as clinical input parameters to predict the exit dose, which is then used to determine the entrance dose. The measured pixel dose maps were compared with calculated doses from TPS for both entrance and exit depth of phantom. The gamma index at 3% dose difference (DD) and 3 mm distance to agreement (DTA) resulted in an average of 97% passing for the square fields of 5, 10, 15 and 20 cm. The exit dose EPID dose distributions predicted by the algorithm were in better agreement with TPS-calculated doses than phantom entrance dose distributions.

  10. Quality assurance of MLC leaf position accuracy and relative dose effect at the MLC abutment region using an electronic portal imaging device

    International Nuclear Information System (INIS)

    Sumida, Iori; Yamaguchi, Hajime; Kizaki, Hisao; Koizumi, Masahiko; Ogata, Toshiyuki; Takahashi, Yutaka; Yoshioka, Yasuo

    2012-01-01

    We investigated an electronic portal image device (EPID)-based method to see whether it provides effective and accurate relative dose measurement at abutment leaves in terms of positional errors of the multi-leaf collimator (MLC) leaf position. A Siemens ONCOR machine was used. For the garden fence test, a rectangular field (0.2x20 cm) was sequentially irradiated 11 times at 2-cm intervals. Deviations from planned leaf positions were calculated. For the nongap test, relative doses at the MLC abutment region were evaluated by sequential irradiation of a rectangular field (2x20 cm) 10 times with a MLC separation of 2 cm without a leaf gap. The integral signal in a region of interest was set to position A (between leaves) and B (neighbor of A). A pixel value at position B was used as background and the pixel ratio (A/Bx100) was calculated. Both tests were performed at four gantry angles (0, 90, 180 and 270deg) four times over 1 month. For the nongap test the difference in pixel ratio between the first and last period was calculated. Regarding results, average deviations from planned positions with the garden fence test were within 0.5 mm at all gantry angles, and at gantry angles of 90 and 270deg tended to decrease gradually over the month. For the nongap test, pixel ratio tended to increase gradually in all leaves, leading to a decrease in relative doses at abutment regions. This phenomenon was affected by both gravity arising from the gantry angle, and the hardware-associated contraction of field size with this type of machine. (author)

  11. TH-AB-202-02: Real-Time Verification and Error Detection for MLC Tracking Deliveries Using An Electronic Portal Imaging Device

    International Nuclear Information System (INIS)

    J Zwan, B; Colvill, E; Booth, J; J O’Connor, D; Keall, P; B Greer, P

    2016-01-01

    Purpose: The added complexity of the real-time adaptive multi-leaf collimator (MLC) tracking increases the likelihood of undetected MLC delivery errors. In this work we develop and test a system for real-time delivery verification and error detection for MLC tracking radiotherapy using an electronic portal imaging device (EPID). Methods: The delivery verification system relies on acquisition and real-time analysis of transit EPID image frames acquired at 8.41 fps. In-house software was developed to extract the MLC positions from each image frame. Three comparison metrics were used to verify the MLC positions in real-time: (1) field size, (2) field location and, (3) field shape. The delivery verification system was tested for 8 VMAT MLC tracking deliveries (4 prostate and 4 lung) where real patient target motion was reproduced using a Hexamotion motion stage and a Calypso system. Sensitivity and detection delay was quantified for various types of MLC and system errors. Results: For both the prostate and lung test deliveries the MLC-defined field size was measured with an accuracy of 1.25 cm 2 (1 SD). The field location was measured with an accuracy of 0.6 mm and 0.8 mm (1 SD) for lung and prostate respectively. Field location errors (i.e. tracking in wrong direction) with a magnitude of 3 mm were detected within 0.4 s of occurrence in the X direction and 0.8 s in the Y direction. Systematic MLC gap errors were detected as small as 3 mm. The method was not found to be sensitive to random MLC errors and individual MLC calibration errors up to 5 mm. Conclusion: EPID imaging may be used for independent real-time verification of MLC trajectories during MLC tracking deliveries. Thresholds have been determined for error detection and the system has been shown to be sensitive to a range of delivery errors.

  12. A high efficiency superconducting nanowire single electron detector

    NARCIS (Netherlands)

    Rosticher, M.; Ladan, F.R.; Maneval, J.P.; Dorenbos, S.N.; Zijlstra, T.; Klapwijk, T.M.; Zwiller, V.; Lupa?cu, A.; Nogues, G.

    2010-01-01

    We report the detection of single electrons using a Nb0.7Ti0.3N superconducting wire deposited on an oxidized silicon substrate. While it is known that this device is sensitive to single photons, we show that it also detects single electrons with kilo-electron-volt energy emitted from the cathode of

  13. Software engineering knowledge at your fingertips: Experiences with a software engineering-portal

    OpenAIRE

    Punter, T.; Kalmar, R.

    2003-01-01

    In order to keep up the pace with technology development, knowledge on Software Engineering (SE) methods, techniques, and tools is required. For an effective and efficient knowledge transfer, especially Small and Medium-sized Enterprises (SMEs) might benefit from Software Engineering Portals (SE-Portals). This paper provides an analysis of SE-Portals by distinguishing two types: 1) the Knowledge Portal and 2) the Knowledge & Community Portal. On behalf of the analysis we conclude that most SE...

  14. Determination of local absolute detection efficiency of a ceratron with 55Fe Auger electrons

    International Nuclear Information System (INIS)

    Mori, C.; Sugiyama, T.; Watanabe, T.

    1983-01-01

    The local absolute detection efficiency of a Ceratron (channel electron multiplier made of ceramics) was determined with collimated Mn K Auger electrons ( 5 keV) emitted from 55 Fe as a function of electron incident position and applied voltage. The local efficiency at the channel inlet did not depend so much on the applied voltage. The efficiency at the funnel increased with the applied voltage, while it was always lower than that at the channel inlet. (orig.)

  15. Enhanced Electron Efficiency in an X-ray Diode

    International Nuclear Information System (INIS)

    Sun, K.; MacNeil, L.

    2010-01-01

    The goal for this research is to optimize the XRD structure and usage configurations and increase the efficiency of the XRD. This research was successful in optimizing the XRD structure and usage configurations, thus creating a high efficiency XRD. Best efficiency occurs when there is an angle between the photocathode and incident X-rays.

  16. Use of the statistical control of processes through checking before treatment realised with the ionization chamber and by electronic portal system of imaging (E.P.I.D.) in intensity modulated radiotherapy (I.M.R.T.); Utilisation de la maitrise statistique des processus dans le cadre des controles avant traitement realises avec la chambre d'ionisation et par systeme d'imagerie portale electronique (EPID) en radiotherapie conformationnelle avec modulation d'intensite (RCMI)

    Energy Technology Data Exchange (ETDEWEB)

    Villani, N.; Gerard, K.; Noel, A. [Nancy univ., Lab. de Recherche en Radiophysique, CRAN UMR 7039, CNRS, Centre Alexis-Vautrin, 54 - Vandoeuvre-les-Nancy (France); Marchesi, V.; Huger, S. [Centre Alexis-Vautrin, Unite de Radiophysique Medicale, 54 - Vandoeuvre-les-Nancy (France)

    2009-10-15

    The expected results are to demonstrate that it is possible to reduce the times devoted to the pre-treatment controls, while keeping an optimal safety, on substituting the measures of the ionization chamber by this one of the electronic portal imaging device (E.P.I.D.). (N.C.)

  17. Effect of resonant-to-bulk electron momentum transfer on the efficiency of electron-cyclotron current drive

    International Nuclear Information System (INIS)

    Matsuda, Y.; Smith, G.R.; Cohen, R.H.

    1988-01-01

    Efficiency of current drive by electron-cyclotron waves is investigated numerically by a bounce-average Fokker-Planck code to elucidate the effects of momentum transfer from resonant to bulk electrons, finite bulk temperature relative to the energy of resonant electrons, and trapped electrons. Comparisons are made with existing theories to assess their validity and quantitative difference between theory and code results. Difference of nearly a factor of 2 was found in efficiency between some theory and code results. 4 refs., 4 figs

  18. Near-infrared branding efficiently correlates light and electron microscopy.

    Science.gov (United States)

    Bishop, Derron; Nikić, Ivana; Brinkoetter, Mary; Knecht, Sharmon; Potz, Stephanie; Kerschensteiner, Martin; Misgeld, Thomas

    2011-06-05

    The correlation of light and electron microscopy of complex tissues remains a major challenge. Here we report near-infrared branding (NIRB), which facilitates such correlation by using a pulsed, near-infrared laser to create defined fiducial marks in three dimensions in fixed tissue. As these marks are fluorescent and can be photo-oxidized to generate electron contrast, they can guide re-identification of previously imaged structures as small as dendritic spines by electron microscopy.

  19. Implementation of a pedagogically efficient system for electronic testing

    OpenAIRE

    Preskar, Peter

    2012-01-01

    Nowadays online learning is a very common process. Together with online learning there has been strong development of online assessment systems. Time is money and online assessment or electronic tests save us exactly that - time. For a teacher and for a student it enables fast feedback information. The diploma thesis at first presents information and communications technology (ICT) and the role of ICT in development of electronic tests and standardisation of records of electronic tests. I...

  20. Efficient O(N) integration for all-electron electronic structure calculation using numeric basis functions

    International Nuclear Information System (INIS)

    Havu, V.; Blum, V.; Havu, P.; Scheffler, M.

    2009-01-01

    We consider the problem of developing O(N) scaling grid-based operations needed in many central operations when performing electronic structure calculations with numeric atom-centered orbitals as basis functions. We outline the overall formulation of localized algorithms, and specifically the creation of localized grid batches. The choice of the grid partitioning scheme plays an important role in the performance and memory consumption of the grid-based operations. Three different top-down partitioning methods are investigated, and compared with formally more rigorous yet much more expensive bottom-up algorithms. We show that a conceptually simple top-down grid partitioning scheme achieves essentially the same efficiency as the more rigorous bottom-up approaches.

  1. The cumulative verification image analysis tool for offline evaluation of portal images

    International Nuclear Information System (INIS)

    Wong, John; Yan Di; Michalski, Jeff; Graham, Mary; Halverson, Karen; Harms, William; Purdy, James

    1995-01-01

    Purpose: Daily portal images acquired using electronic portal imaging devices contain important information about the setup variation of the individual patient. The data can be used to evaluate the treatment and to derive correction for the individual patient. The large volume of images also require software tools for efficient analysis. This article describes the approach of cumulative verification image analysis (CVIA) specifically designed as an offline tool to extract quantitative information from daily portal images. Methods and Materials: The user interface, image and graphics display, and algorithms of the CVIA tool have been implemented in ANSCI C using the X Window graphics standards. The tool consists of three major components: (a) definition of treatment geometry and anatomical information; (b) registration of portal images with a reference image to determine setup variation; and (c) quantitative analysis of all setup variation measurements. The CVIA tool is not automated. User interaction is required and preferred. Successful alignment of anatomies on portal images at present remains mostly dependent on clinical judgment. Predefined templates of block shapes and anatomies are used for image registration to enhance efficiency, taking advantage of the fact that much of the tool's operation is repeated in the analysis of daily portal images. Results: The CVIA tool is portable and has been implemented on workstations with different operating systems. Analysis of 20 sequential daily portal images can be completed in less than 1 h. The temporal information is used to characterize setup variation in terms of its systematic, random and time-dependent components. The cumulative information is used to derive block overlap isofrequency distributions (BOIDs), which quantify the effective coverage of the prescribed treatment area throughout the course of treatment. Finally, a set of software utilities is available to facilitate feedback of the information for

  2. High-efficiency free-electron-laser experiments

    International Nuclear Information System (INIS)

    Boyer, K.; Brau, C.A.; Goldstein, J.C.; Hohla, K.L.; Newnam, B.E.; Stein, W.E.; Warren, R.W.; Winston, J.G.

    1983-01-01

    Experiments with a tapered-wiggler free-electron laser have demonstrated extraction of about 3% of the energy from the electron beam and measured the corresponding optical emission. These results are in excellent agreement with theory and represent an order-of-magnitude improvement over all previous results

  3. SU-E-T-775: Use of Electronic Portal Imaging Device (EPID) for Quality Assurance (QA) of Electron Beams On Varian Truebeam System

    Energy Technology Data Exchange (ETDEWEB)

    Cai, B; Yaddanapudi, S; Sun, B; Li, H; Noel, C; Mutic, S; Goddu, S [Department of Radiation Oncology, Washington University in St Louis, St. Louis, MO (United States)

    2015-06-15

    Purpose: In a previous study we have demonstrated the feasibility of using EPID to QA electron beam parameters on a single Varian TrueBeam LINAC. This study aims to provide further investigation on (1) reproducibility of using EPID to detect electron beam energy changes on multiple machines and (2) evaluation of appropriate calibration methods to compare results from different EPIDs. Methods: Ad-hoc mode electron beam images were acquired in developer mode with XML code. Electron beam data were collected on a total of six machines from four institutions. A custom-designed double-wedge phantom was placed on the EPID detector. Two calibration methods - Pixel Sensitivity Map (PSM) and Large Source-to-Imager Distance Flood Field (LSID-FF) - were used. To test the sensitivity of EPID in detecting energy drifts, Bending Magnet Current (BMC) was detuned to invoke energy changes corresponding to ∼±1.5 mm change in R50% of PDD on two machines from two institutions. Percent depth ionization (PDI) curves were then analyzed and compared with the respective baseline images using LSID-FF calibration. For reproducibility testing, open field EPID images and images with a standard testing phantom were collected on multiple machines. Images with and without PSM correction for same energies on different machines were overlaid and compared. Results: Two pixel shifts were observed in PDI curve when energy changes exceeded the TG142 tolerance. PSM showed the potential to correct the differences in pixel response of different imagers. With PSM correction, the histogram of images differences obtained from different machines showed narrower distributions than those images without PSM correction. Conclusion: EPID is sensitive for electron energy changes and the results are reproducible on different machines. When overlaying images from different machines, PSM showed the ability to partially eliminate the intrinsic variation of various imagers. Research Funding from Varian Medical Systems

  4. Noncirrhotic portal hypertension.

    Science.gov (United States)

    Da, Ben L; Koh, Christopher; Heller, Theo

    2018-05-01

    Noncirrhotic portal hypertension represents a heterogeneous group of liver disorders that is characterized by portal hypertension in the absence of cirrhosis. The purpose of this review is to serve as a guide on how to approach a patient with noncirrhotic portal hypertension with a focus on recent developments. Recent studies pertaining to noncirrhotic portal hypertension have investigated aetiological causes, mechanisms of disease, noninvasive diagnostic modalities, clinical characteristics in the paediatric population and novel treatment targets. Noncirrhotic portal hypertension is an underappreciated clinical entity that can be difficult to diagnosis without a healthy suspicion. Diagnosis then relies on a comprehensive understanding of the causes and clinical manifestations of this disease, as well as a careful interpretation of the liver biopsy. Noninvasive approaches to diagnosis may play a significant role moving forward in this disease. Treatment in NCPH remains largely targeted at the individual sequalae of portal hypertension.

  5. Hepatic angiography: Portal hypertension

    International Nuclear Information System (INIS)

    Oliver, T.W. Jr.; Sones, P.J. Jr.

    1985-01-01

    Portal hypertension is usually a manifestation of underlying hepatic parenchymal disease, although it may be secondary to portal or hepatic venous thrombosis and rarely to hyperdynamic portal states. Portal hypertension may present as encephalopathy, ascites, jaundice, hepatic failure, or catastrophic upper gastrointestinal hemorrhage. Radiologic investigation should include indirect or direct measurements of portal pressure, assessment of portal venous perfusion, visualization of collaterals, and demonstration of arterial and venous anatomy for potential shunt procedure. Following survival of initial variceal bleeding, the most effective procedure to prevent recurrent hemorrhage is a shunt to decompress the varices. The decision whether to intervene medically or surgically during the acute hemorrhagic episode as well as the type of shunt used to prevent future hemorrhage is the subject of continuing controversy

  6. Pediatric portal hypertension

    Science.gov (United States)

    Vogel, Clarissa Barbon

    2017-01-01

    Abstract: Pediatric portal hypertension management is a team approach between the patient, the patient's family, the primary caregiver, and specialty providers. Evidence-based practice guidelines have not been established in pediatrics. This article serves as a review for the primary care NP in the management of pediatric portal hypertension, discussing the etiology, pathophysiology, and clinical presentation of pediatric portal hypertension, diagnostic tests, and treatment and management options. PMID:28406835

  7. Usability of Discovery Portals

    OpenAIRE

    Bulens, J.D.; Vullings, L.A.E.; Houtkamp, J.M.; Vanmeulebrouk, B.

    2013-01-01

    As INSPIRE progresses to be implemented in the EU, many new discovery portals are built to facilitate finding spatial data. Currently the structure of the discovery portals is determined by the way spatial data experts like to work. However, we argue that the main target group for discovery portals are not spatial data experts but professionals with limited spatial knowledge, and a focus outside the spatial domain. An exploratory usability experiment was carried out in which three discovery p...

  8. Tunneling explains efficient electron transport via protein junctions.

    Science.gov (United States)

    Fereiro, Jerry A; Yu, Xi; Pecht, Israel; Sheves, Mordechai; Cuevas, Juan Carlos; Cahen, David

    2018-05-15

    Metalloproteins, proteins containing a transition metal ion cofactor, are electron transfer agents that perform key functions in cells. Inspired by this fact, electron transport across these proteins has been widely studied in solid-state settings, triggering the interest in examining potential use of proteins as building blocks in bioelectronic devices. Here, we report results of low-temperature (10 K) electron transport measurements via monolayer junctions based on the blue copper protein azurin (Az), which strongly suggest quantum tunneling of electrons as the dominant charge transport mechanism. Specifically, we show that, weakening the protein-electrode coupling by introducing a spacer, one can switch the electron transport from off-resonant to resonant tunneling. This is a consequence of reducing the electrode's perturbation of the Cu(II)-localized electronic state, a pattern that has not been observed before in protein-based junctions. Moreover, we identify vibronic features of the Cu(II) coordination sphere in transport characteristics that show directly the active role of the metal ion in resonance tunneling. Our results illustrate how quantum mechanical effects may dominate electron transport via protein-based junctions.

  9. Patient portals and broadband internet inequality.

    Science.gov (United States)

    Perzynski, Adam T; Roach, Mary Joan; Shick, Sarah; Callahan, Bill; Gunzler, Douglas; Cebul, Randall; Kaelber, David C; Huml, Anne; Thornton, John Daryl; Einstadter, Douglas

    2017-09-01

    Patient portals have shown potential for increasing health care quality and efficiency. Internet access and other factors influencing patient portal use could worsen health disparities. Observational study of adults with 1 or more visits to the outpatient clinics of an urban public health care system from 2012 to 2015. We used mixed effects logistic regression to evaluate the association between broadband internet access and (1) patient portal initiation (whether a patient logged in at least 1 time) and (2) messaging, controlling for demographic and neighborhood characteristics. There were 243 248 adults with 1 or more visits during 2012-2015 and 70 835 (29.1%) initiated portal use. Portal initiation was 34.1% for whites, 23.4% for blacks, and 23.8% for Hispanics, and was lower for Medicaid (26.5%), Medicare (23.4%), and uninsured patients (17.4%) than commercially insured patients (39.3%). In multivariate analysis, both initiation of portal use (odds ratio [OR] = 1.24 per quintile, 95% confidence interval [CI], 1.23-1.24, P  internet access. The majority of adults with outpatient visits to a large urban health care system did not use the patient portal, and initiation of use was lower for racial and ethnic minorities, persons of lower socioeconomic status, and those without neighborhood broadband internet access. These results suggest the emergence of a digital divide in patient portal use. Given the scale of investment in patient portals and other internet-dependent health information technologies, efforts are urgently needed to address this growing inequality. © The Author 2017. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  10. An Efficient Method for Electron-Atom Scattering Using Ab-initio Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuan; Yang, Yonggang; Xiao, Liantuan; Jia, Suotang [Shanxi University, Taiyuan (China)

    2017-02-15

    We present an efficient method based on ab-initio calculations to investigate electron-atom scatterings. Those calculations profit from methods implemented in standard quantum chemistry programs. The new approach is applied to electron-helium scattering. The results are compared with experimental and other theoretical references to demonstrate the efficiency of our method.

  11. Highly efficient exciplex organic light-emitting diodes incorporating a heptazine derivative as an electron acceptor.

    Science.gov (United States)

    Li, Jie; Nomura, Hiroko; Miyazaki, Hiroshi; Adachi, Chihaya

    2014-06-11

    Highly efficient exciplex systems incorporating a heptazine derivative () as an electron acceptor and 1,3-di(9H-carbazol-9-yl)benzene () as an electron donor are developed. An organic light-emitting diode containing 8 wt% : as an emitting layer exhibits a maximum external quantum efficiency of 11.3%.

  12. Modulation transfer function and detective quantum efficiency of electron bombarded charge coupled device detector for low energy electrons

    Czech Academy of Sciences Publication Activity Database

    Horáček, Miroslav

    2005-01-01

    Roč. 76, č. 9 (2005), 093704:1-6 ISSN 0034-6748 R&D Projects: GA ČR(CZ) GA202/03/1575 Keywords : electron bombarded CCD * modulation transfer function * detective quantum efficiency Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.235, year: 2005

  13. Quality assurance of geometric accuracy based on an electronic portal imaging device and log data analysis for Dynamic WaveArc irradiation.

    Science.gov (United States)

    Hirashima, Hideaki; Miyabe, Yuki; Nakamura, Mitsuhiro; Mukumoto, Nobutaka; Mizowaki, Takashi; Hiraoka, Masahiro

    2018-04-06

    The purpose of this study was to develop a simple verification method for the routine quality assurance (QA) of Dynamic WaveArc (DWA) irradiation using electronic portal imaging device (EPID) images and log data analysis. First, an automatic calibration method utilizing the outermost multileaf collimator (MLC) slits was developed to correct the misalignment between the center of the EPID and the beam axis. Moreover, to verify the detection accuracy of the MLC position according to the EPID images, various positions of the MLC with intentional errors in the range 0.1-1 mm were assessed. Second, to validate the geometric accuracy during DWA irradiation, tests were designed in consideration of three indices. Test 1 evaluated the accuracy of the MLC position. Test 2 assessed dose output consistency with variable dose rate (160-400 MU/min), gantry speed (2.2-6°/s), and ring speed (0.5-2.7°/s). Test 3 validated dose output consistency with variable values of the above parameters plus MLC speed (1.6-4.2 cm/s). All tests were delivered to the EPID and compared with those obtained using a stationary radiation beam with a 0° gantry angle. Irradiation log data were recorded simultaneously. The 0.1-mm intentional error on the MLC position could be detected by the EPID, which is smaller than the EPID pixel size. In Test 1, the MLC slit widths agreed within 0.20 mm of their exposed values. The averaged root-mean-square error (RMSE) of the dose outputs was less than 0.8% in Test 2 and Test 3. Using log data analysis in Test 3, the RMSE between the planned and recorded data was 0.1 mm, 0.12°, and 0.07° for the MLC position, gantry angle, and ring angle, respectively. The proposed method is useful for routine QA of the accuracy of DWA. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  14. Application of the No Action Level (NAL) protocol to correct for prostate motion based on electronic portal imaging of implanted markers

    International Nuclear Information System (INIS)

    Boer, Hans C.J. de; Os, Marjolein J.H. van; Jansen, Peter P.; Heijmen, Ben J.M.

    2005-01-01

    Purpose: To evaluate the efficacy of the No Action Level (NAL) off-line correction protocol in the reduction of systematic prostate displacements as determined from electronic portal images (EPI) using implanted markers. Methods and materials: Four platinum markers, two near the apex and two near the base of the prostate, were implanted for localization purposes in patients who received fractionated high dose rate brachytherapy. During the following course of 25 fractions of external beam radiotherapy, the position of each marker relative to the corresponding position in digitally reconstructed radiographs (DRRs) was measured in EPI in 15 patients for on average 17 fractions per patient. These marker positions yield the composite displacements due to both setup error and internal prostate motion, relative to the planning computed tomography scan. As the NAL protocol is highly effective in reducing systematic errors (recurring each fraction) due to setup inaccuracy alone, we investigated its efficacy in reducing systematic composite displacements. The analysis was performed for the center of mass (COM) of the four markers, as well as for the cranial and caudal markers separately. Furthermore, the impact of prostate rotation on the achieved positioning accuracy was determined. Results: In case of no setup corrections, the standard deviations of the systematic composite displacements of the COM were 3-4 mm in the craniocaudal and anterior-posterior directions, and 2 mm in the left-right direction. The corresponding SDs of the random displacements (interfraction fluctuations) were 2-3 mm in each direction. When applying a NAL protocol based on three initial treatment fractions, the SDs of the systematic COM displacements were reduced to 1-2 mm. Displacements at the cranial end of the prostate were slightly larger than at the caudal end, and quantitative analysis showed this originates from left-right axis rotations about the prostate apex. Further analysis revealed

  15. Saturation mechanism and improvement of conversion efficiency of free electron laser

    International Nuclear Information System (INIS)

    Taguchi, T.; Mima, K.; Mochizuki, T.

    1980-01-01

    Saturation mechanisms of free electron laser are investigated in the Compton regime. It is found that the saturation occurs due to quasi-linear energy spreading of electron beam in the case of many mode excitation. The energy conversion efficiency remains low even if many modes are taken into account. For improvement of the conversion efficiency, effects of reacceleration by a traveling wave are investigated and turn out to increase the efficiency up to more than 50%. (author)

  16. Portal cholangiopathy: case report

    Directory of Open Access Journals (Sweden)

    Maria Cecilia Almeida Maia

    2014-01-01

    Full Text Available The present report describes the case of a child that after blunt abdominal trauma presented with portal thrombosis followed by progressive splenomegaly and jaundice. Ultrasonography and percutaneous cholangiography revealed biliary dilatation secondary to choledochal stenosis caused by dilated peribiliary veins, characterizing a case of portal biliopathy. The present case report is aimed at presenting an uncommon cause of this condition.

  17. Roadside Tracker Portal-less Portal Monitor

    Energy Technology Data Exchange (ETDEWEB)

    Ziock, Klaus-Peter [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cheriyadat, Anil M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bradley, Eric Craig [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cunningham, Mark F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fabris, Lorenzo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Goddard, Jr, James Samuel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hornback, Donald Eric [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Karnowski, Thomas Paul [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kerekes, Ryan A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Newby, Jason [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2013-07-01

    This report documents the full development cycle of the Roadside Tracker (RST) Portal-less Portal monitor (Fig. 1) funded by DHS DNDO. The project started with development of a proof-of-feasibility proto-type, proceeded through design and construction of a proof-of-concept (POC) prototype, a test-and-evaluation phase, participation in a Limited Use Exercise that included the Standoff Radiation Detections Systems developed under an Advanced Technology Demonstration and concluded with participation in a Characterization Study conducted by DNDO.

  18. The XCAT Science Portal

    Directory of Open Access Journals (Sweden)

    Sriram Krishnan

    2002-01-01

    Full Text Available This paper describes the design and prototype implementation of the XCAT Grid Science Portal. The portal lets grid application programmers script complex distributed computations and package these applications with simple interfaces for others to use. Each application is packaged as a notebook which consists of web pages and editable parameterized scripts. The portal is a workstation-based specialized personal web server, capable of executing the application scripts and launching remote grid applications for the user. The portal server can receive event streams published by the application and grid resource information published by Network Weather Service (NWS [35] or Autopilot [16] sensors. Notebooks can be published and stored in web based archives for others to retrieve and modify. The XCAT Grid Science Portal has been tested with various applications, including the distributed simulation of chemical processes in semiconductor manufacturing and collaboratory support for X-ray crystallographers.

  19. Highly efficient electron gun with a single-atom electron source

    International Nuclear Information System (INIS)

    Ishikawa, Tsuyoshi; Urata, Tomohiro; Cho, Boklae; Rokuta, Eiji; Oshima, Chuhei; Terui, Yoshinori; Saito, Hidekazu; Yonezawa, Akira; Tsong, Tien T.

    2007-01-01

    The authors have demonstrated highly collimated electron-beam emission from a practical electron gun with a single-atom electron source; ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources such as a cold field emission gun and a Zr/O/W Schottky gun. At the pressure of less than 1x10 -9 Pa, the authors observed stable emission of 20 nA, which generates the specimen current of 5 pA required for scanning electron microscopes

  20. Next Gen One Portal Usability Evaluation

    Science.gov (United States)

    Cross, E. V., III; Perera, J. S.; Hanson, A. M.; English, K.; Vu, L.; Amonette, W.

    2018-01-01

    Each exercise device on the International Space Station (ISS) has a unique, customized software system interface with unique layouts / hierarchy, and operational principles that require significant crew training. Furthermore, the software programs are not adaptable and provide no real-time feedback or motivation to enhance the exercise experience and/or prevent injuries. Additionally, the graphical user interfaces (GUI) of these systems present information through multiple layers resulting in difficulty navigating to the desired screens and functions. These limitations of current exercise device GUI's lead to increased crew time spent on initiating, loading, performing exercises, logging data and exiting the system. To address these limitations a Next Generation One Portal (NextGen One Portal) Crew Countermeasure System (CMS) was developed, which utilizes the latest industry guidelines in GUI designs to provide an intuitive ease of use approach (i.e., 80% of the functionality gained within 5-10 minutes of initial use without/limited formal training required). This is accomplished by providing a consistent interface using common software to reduce crew training, increase efficiency & user satisfaction while also reducing development & maintenance costs. Results from the usability evaluations showed the NextGen One Portal UI having greater efficiency, learnability, memorability, usability and overall user experience than the current Advanced Resistive Exercise Device (ARED) UI used by astronauts on ISS. Specifically, the design of the One-Portal UI as an app interface similar to those found on the Apple and Google's App Store, assisted many of the participants in grasping the concepts of the interface with minimum training. Although the NextGen One-Portal UI was shown to be an overall better interface, observations by the test facilitators noted specific exercise tasks appeared to have a significant impact on the NextGen One-Portal UI efficiency. Future updates to

  1. Portal Vein Stenting for Portal Biliopathy with Jaundice

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Dongho, E-mail: mesentery@naver.com; Park, Kwang Bo, E-mail: kbjh.park@samsung.com [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center (Korea, Republic of); Lim, Seong Joo [Konyang University, Department of Radiology, College of Medicine, Konyang University Hospital (Korea, Republic of); Hwang, Jin Ho [Hallym University Sacred Heart Hospital, Department of Radiology (Korea, Republic of); Sinn, Dong Hyun [Sungkyunkwan University School of Medicine, Department of Medicine, Samsung Medical Center (Korea, Republic of)

    2016-04-15

    Portal biliopathy refers to obstruction of the bile duct by dilated peri- or para-ductal collateral channels following the main portal vein occlusion from various causes. Surgical shunt operation or endoscopic treatment has been reported. Herein, we report a case of portal biliopathy that was successfully treated by interventional portal vein recanalization.

  2. Inpatient Portals for Hospitalized Patients and Caregivers: A Systematic Review.

    Science.gov (United States)

    Kelly, Michelle M; Coller, Ryan J; Hoonakker, Peter Lt

    2018-06-01

    Patient portals, web-based personal health records linked to electronic health records (EHRs), provide patients access to their healthcare information and facilitate communication with providers. Growing evidence supports portal use in ambulatory settings; however, only recently have portals been used with hospitalized patients. Our objective was to review the literature evaluating the design, use, and impact of inpatient portals, which are patient portals designed to give hospitalized patients and caregivers inpatient EHR clinical information for the purpose of engaging them in hospital care. Literature was reviewed from 2006 to 2017 in PubMed, Web of Science, CINALPlus, Cochrane, and Scopus to identify English language studies evaluating patient portals, engagement, and inpatient care. Data were analyzed considering the following 3 themes: inpatient portal design, use and usability, and impact. Of 731 studies, 17 were included, 9 of which were published after 2015. Most studies were qualitative with small samples focusing on inpatient portal design; 1 nonrandomized trial was identified. Studies described hospitalized patients' and caregivers' information needs and design recommendations. Most patient and caregiver participants in included studies were interested in using an inpatient portal, used it when offered, and found it easy to use and/or useful. Evidence supporting the role of inpatient portals in improving patient and caregiver engagement, knowledge, communication, and care quality and safety is limited. Included studies indicated providers had concerns about using inpatient portals; however, the extent to which these concerns have been realized remains unclear. Inpatient portal research is emerging. Further investigation is needed to optimally design inpatient portals to maximize potential benefits for hospitalized patients and caregivers while minimizing unintended consequences for healthcare teams. © 2017 Society of Hospital Medicine.

  3. Portal vein thrombosis.

    Science.gov (United States)

    Chawla, Yogesh K; Bodh, Vijay

    2015-03-01

    Portal vein thrombosis is an important cause of portal hypertension. PVT occurs in association with cirrhosis or as a result of malignant invasion by hepatocellular carcinoma or even in the absence of associated liver disease. With the current research into its genesis, majority now have an underlying prothrombotic state detectable. Endothelial activation and stagnant portal blood flow also contribute to formation of the thrombus. Acute non-cirrhotic PVT, chronic PVT (EHPVO), and portal vein thrombosis in cirrhosis are the three main variants of portal vein thrombosis with varying etiological factors and variability in presentation and management. Procoagulant state should be actively investigated. Anticoagulation is the mainstay of therapy for acute non-cirrhotic PVT, with supporting evidence for its use in cirrhotic population as well. Chronic PVT (EHPVO) on the other hand requires the management of portal hypertension as such and with role for anticoagulation in the setting of underlying prothrombotic state, however data is awaited in those with no underlying prothrombotic states. TIPS and liver transplant may be feasible even in the setting of PVT however proper selection of candidates and type of surgery is warranted. Thrombolysis and thrombectomy have some role. TARE is a new modality for management of HCC with portal vein invasion.

  4. Mechanical characterization of the Varian Exact-arm and R-arm support systems for eight aS500 electronic portal imaging devices

    International Nuclear Information System (INIS)

    Grattan, Mark W. D.; McGarry, Conor K.

    2010-01-01

    Purpose: The aim of this study is to compare the positioning accuracy at different gantry angles of two electronic portal imaging devices (EPIDs) support arm systems by using EPID difference images as a measure for displacement. This work presents a comparison of the mechanical performance of eight Varian aS500 (Varian Medical Systems, Palo Alto, CA) EPIDs, mounted using either the Varian Exact-arm or R-arm. Methods: The mechanical performance of the two arm systems was compared by investigating the variation in sensitivity with gantry angle, both before and after the EPID position was adjusted after gantry rotation. Positional errors were investigated by subtracting images from a reference image taken at gantry 0 deg., and the amplitude of the peaks and troughs at the field edges for longitudinal (radial) and lateral (transverse) profiles across the resulting image was related to the distance of displacement. Calibration curves based on a pixel-by-pixel shift were generated for each EPID and the Varian hand pendant accuracy was compared to the calibration data. Results: The response of the EPIDs was found to change with gantry rotation, with the largest difference at 180 deg. The Exact-arm was found to correct well for any displacement, while the R-arm tended to overcorrect following repositioning using the hand pendant. The calibration curves were consistent within each set of matched linacs, and the hand pendant accuracy was similar for both arm systems, although generally in different directions. With respect to gantry rotation effects, the mechanical performance of the Exact-arm systems was found to be much better than that of the R-arm systems. At gantry positions 90 deg., 270 deg., and 180 deg. the average misalignment in the longitudinal direction was +4.2±0.2, +1.8±1.6, and +7.4±0.5 mm for the R-arms, and +2.9±0.2, +2.1±0.8, and +4.9±0.7 mm for the Exact-arms. In the lateral direction the average positional errors were +2.1±0.4, -4.7±0.4, and -2.5

  5. Electron efficiency measurements with the ATLAS detector using 2012 LHC proton-proton collision data

    Energy Technology Data Exchange (ETDEWEB)

    Aaboud, M. [Univ. Mohamed Premier et LPTPM, Oujda (Morocco). Faculte des Sciences; Aad, G. [CPPM, Aix-Marseille Univ. et CNRS/IN2P3, Marseille (France); Abbott, B. [Oklahoma Univ., Norman, OK (United States). Homer L. Dodge Dept. of Physics and Astronomy; Collaboration: ATLAS Collaboration; and others

    2017-03-15

    This paper describes the algorithms for the reconstruction and identification of electrons in the central region of the ATLAS detector at the Large Hadron Collider (LHC). These algorithms were used for all ATLAS results with electrons in the final state that are based on the 2012 pp collision data produced by the LHC at √(s) = 8 TeV. The efficiency of these algorithms, together with the charge misidentification rate, is measured in data and evaluated in simulated samples using electrons from Z → ee, Z → eeγ and J/ψ → ee decays. For these efficiency measurements, the full recorded data set, corresponding to an integrated luminosity of 20.3 fb{sup -1}, is used. Based on a new reconstruction algorithm used in 2012, the electron reconstruction efficiency is 97% for electrons with E{sub T} = 15 GeV and 99% at E{sub T} = 50 GeV. Combining this with the efficiency of additional selection criteria to reject electrons from background processes or misidentified hadrons, the efficiency to reconstruct and identify electrons at the ATLAS experiment varies from 65 to 95%, depending on the transverse momentum of the electron and background rejection. (orig.)

  6. High Efficiency Driving Electronics for General Illumination LED Luminaires

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyay, Anand

    2012-10-31

    New generation of standalone LED driver platforms developed, which are more efficient These LED Drivers are more efficient (≥90%), smaller in size ( 0.15 in3/watt), lower in cost ( 12 cents/watt in high volumes in millions of units). And these products are very reliable having an operating life of over 50,000 hours. This technology will enable growth of LED light sources in the use. This will also help in energy saving and reducing total life cycle cost of LED units. Two topologies selected for next generation of LED drivers: 1) Value engineered single stage Flyback topology. This is suitable for low powered LED drivers up to 50W power. 2) Two stage boost power factor correction (PFC) plus LLC half bridge platform for higher powers. This topology is suitable for 40W to 300W LED drivers. Three new product platforms were developed to cover a wide range of LED drivers: 1) 120V 40W LED driver, 2) Intellivolt 75W LED driver, & 3) Intellivolt 150W LED driver. These are standalone LED drivers for rugged outdoor lighting applications. Based on these platforms number of products are developed and successfully introduced in the market place meeting key performance, size and cost goals.

  7. Radiation portal evaluation parameters

    International Nuclear Information System (INIS)

    York, R.L.

    1998-01-01

    The detection of the unauthorized movement of radioactive materials is one of the most effective nonproliferation measures. Automatic special nuclear material (SNM) portal monitors are designed to detect this unauthorized movement and are an important part of the safeguard systems at US nuclear facilities. SNM portals differ from contamination monitors because they are designed to have high sensitivity for the low energy gamma-rays associated with highly enriched uranium (HEU) and plutonium. These instruments are now being installed at international borders to prevent the spread of radioactive contamination an SNM. In this paper the parameters important to evaluating radiation portal monitors are discussed. (author)

  8. A chess web portal

    OpenAIRE

    Volf, Žiga

    2011-01-01

    The aim of the thesis was to develop a web portal for chess players, which is intended to be a place for quality chess joining over the Internet and chess education. This need is caused by existing social networks and websites for playing chess, which offer you a very small amount of quality chess joining and education. As a result of the work the chess portal was created. We have presented the development of the chess portal in the thesis, which has all the features the chess players are i...

  9. Efficiency evaluation of an electronic equipment: availability,reliability and maintenance

    International Nuclear Information System (INIS)

    Guyot, C.

    1966-01-01

    This concept of efficiency often called ''system effectiveness'', is presented and analyzed in terms of reliability and maintenance. It allows to define the availability factor of an electronic equipment. A procedure of evaluation is proposed. (A.L.B.)

  10. Classification of cryo electron microscopy images, noisy tomographic images recorded with unknown projection directions, by simultaneously estimating reconstructions and application to an assembly mutant of Cowpea Chlorotic Mottle Virus and portals of the bacteriophage P22

    Science.gov (United States)

    Lee, Junghoon; Zheng, Yili; Yin, Zhye; Doerschuk, Peter C.; Johnson, John E.

    2010-08-01

    Cryo electron microscopy is frequently used on biological specimens that show a mixture of different types of object. Because the electron beam rapidly destroys the specimen, the beam current is minimized which leads to noisy images (SNR substantially less than 1) and only one projection image per object (with an unknown projection direction) is collected. For situations where the objects can reasonably be described as coming from a finite set of classes, an approach based on joint maximum likelihood estimation of the reconstruction of each class and then use of the reconstructions to label the class of each image is described and demonstrated on two challenging problems: an assembly mutant of Cowpea Chlorotic Mottle Virus and portals of the bacteriophage P22.

  11. Comparison between Electronic Portal Imaging Devices and ion chamber matrix for intensity-modulated radiotherapy quality assurance; Comparacao entre Dispositivos Eletronicos de Imagens Portais e matriz de camaras de ionizacao para garantia da qualidade de radioterapia de intensidade modulada

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Thiago B.; Rosa, Luiz A.R., E-mail: thiago.fisimed@gmail.com [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lima, Marilia B., E-mail: thiago.fisimed@gmail.com [Instituto Nacional do Cancer (INCA), Rio de Janeiro, RJ (Brazil). Departamento de Fisica Medica

    2012-08-15

    The treatment with intensity-modulated radiotherapy (IMRT) demands an individual and specific quality assurance procedure. The use of ion chamber matrix is a well establish method to dose distribution verifications, despite the lower spatial resolution. An alternative method arising is the use of the Electronic Portal Imaging Devices (EPIDs). The aim of this paper is to validate the EPID use for quality assurance of IMRT comparing it to the previous method employing an ion chamber matrix. We analyzed 10 treatment planning for different tumor sites and photons energies of the linac Trilogy (Varian Medical Systems). We used Sliding-window IMRT and the measurements were acquired in EPID and in Physikalisch-Technische Werkstaetten (PTW) 2D Array seven29. Two different software were used to analyze the data: Verisoft version 4.0, for Array data; and Eclipse 8.6 with Portal Dosimetry for EPID data. The evaluation of concordance levels between measured and predicted images used the Gamma Index tool with 3% of dose difference and 3 mm of distance to agreement. The EPID showed worse results for approval percentiles, in average 2.17%, and bigger values of average gamma index, although its analysis confirmed the approvals of all planning. This happens because of the better sensitivity generated by the higher spatial resolution of the EPID, 0,784 mm against 1,0 cm of the Array, so it has bigger capacity to identify small dose variations. The EPID, jointly with the Portal Dosimetry, proved to be excellent tools to perform pre-treatment IMRT verifications, providing significant gain in dose distribution analysis. Also, the EPID is easier for positioning, for images manipulation, for data acquisition and analysis and has detection area 60% bigger. (author)

  12. Enhanced Electronic Properties of SnO2 via Electron Transfer from Graphene Quantum Dots for Efficient Perovskite Solar Cells.

    Science.gov (United States)

    Xie, Jiangsheng; Huang, Kun; Yu, Xuegong; Yang, Zhengrui; Xiao, Ke; Qiang, Yaping; Zhu, Xiaodong; Xu, Lingbo; Wang, Peng; Cui, Can; Yang, Deren

    2017-09-26

    Tin dioxide (SnO 2 ) has been demonstrated as an effective electron-transporting layer (ETL) for attaining high-performance perovskite solar cells (PSCs). However, the numerous trap states in low-temperature solution processed SnO 2 will reduce the PSCs performance and result in serious hysteresis. Here, we report a strategy to improve the electronic properties in SnO 2 through a facile treatment of the films with adding a small amount of graphene quantum dots (GQDs). We demonstrate that the photogenerated electrons in GQDs can transfer to the conduction band of SnO 2 . The transferred electrons from the GQDs will effectively fill the electron traps as well as improve the conductivity of SnO 2 , which is beneficial for improving the electron extraction efficiency and reducing the recombination at the ETLs/perovskite interface. The device fabricated with SnO 2 :GQDs could reach an average power conversion efficiency (PCE) of 19.2 ± 1.0% and a highest steady-state PCE of 20.23% with very little hysteresis. Our study provides an effective way to enhance the performance of perovskite solar cells through improving the electronic properties of SnO 2 .

  13. ASKME Enterprise Portal (internal) -

    Data.gov (United States)

    Department of Transportation — The ASKME Enterprise Portal Internal (AEPi) is envisioned to be an integrated, single-point-of-entry solution that contains modular components. The AEPi will provide...

  14. Influence of electron transport on the efficiency of polymer-based solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kuxhaus, Viktor; Jaiser, Frank; Neher, Dieter [Institute of Physics and Astronomy, University Potsdam (Germany); Voges, Frank [Merck KGaA, Darmstadt (Germany)

    2010-07-01

    Recently, we showed that the mobility of electrons in polymer-based solar cells has a large influence on the overall performance of such devices. Here, we investigate the correlation between electron mobility and charge generation efficiency in organic bilayer solar cells for a series of electron transporting materials (ETMs) with comparable HOMO and LUMO levels. The electron mobility was measured by transient electroluminescence. Here, a thin M3EH-PPV was used as a sensing layer. The interface between M3EH-PPV and ETM acted as a recombination zone of electrons transported through the ETM layer and holes that are blocked at the interface. Therefore, the electron mobility can easily be determined from the onset of M3EH-PPV emission which is spectrally well separated from the ETM emission. To determine the charge generation efficiency, the different ETMs were combined in bilayer solar cell with PFB as donator.

  15. To what extent can charge localization influence electron injection efficiency at graphene-porphyrin interfaces?

    KAUST Repository

    Parida, Manas R.

    2015-04-28

    Controlling the electron transfer process at donor- acceptor interfaces is a research direction that has not yet seen much progress. Here, with careful control of the charge localization on the porphyrin macrocycle using β -Cyclodextrin as an external cage, we are able to improve the electron injection efficiency from cationic porphyrin to graphene carboxylate by 120% . The detailed reaction mechanism is also discussed.

  16. Liferay Portal Systems Development

    CERN Document Server

    Yuan, Jonas X

    2012-01-01

    This book focuses on teaching by example. Every chapter provides an overview, and then dives right into hands-on examples so you can see and play with the solution in your own environment. This book is for Java developers who don't need any prior experience with Liferay portal. Although Liferay portal makes heavy use of open source frameworks, no prior experience of using these is assumed.

  17. Electron linac for medical isotope production with improved energy efficiency and isotope recovery

    Science.gov (United States)

    Noonan, John; Walters, Dean; Virgo, Matt; Lewellen, John

    2015-09-08

    A method and isotope linac system are provided for producing radio-isotopes and for recovering isotopes. The isotope linac is an energy recovery linac (ERL) with an electron beam being transmitted through an isotope-producing target. The electron beam energy is recollected and re-injected into an accelerating structure. The ERL provides improved efficiency with reduced power requirements and provides improved thermal management of an isotope target and an electron-to-x-ray converter.

  18. Biology of portal hypertension.

    Science.gov (United States)

    McConnell, Matthew; Iwakiri, Yasuko

    2018-02-01

    Portal hypertension develops as a result of increased intrahepatic vascular resistance often caused by chronic liver disease that leads to structural distortion by fibrosis, microvascular thrombosis, dysfunction of liver sinusoidal endothelial cells (LSECs), and hepatic stellate cell (HSC) activation. While the basic mechanisms of LSEC and HSC dysregulation have been extensively studied, the role of microvascular thrombosis and platelet function in the pathogenesis of portal hypertension remains to be clearly characterized. As a secondary event, portal hypertension results in splanchnic and systemic arterial vasodilation, leading to the development of a hyperdynamic circulatory syndrome and subsequently to clinically devastating complications including gastroesophageal varices and variceal hemorrhage, hepatic encephalopathy from the formation of portosystemic shunts, ascites, and renal failure due to the hepatorenal syndrome. This review article discusses: (1) mechanisms of sinusoidal portal hypertension, focusing on HSC and LSEC biology, pathological angiogenesis, and the role of microvascular thrombosis and platelets, (2) the mesenteric vasculature in portal hypertension, and (3) future directions for vascular biology research in portal hypertension.

  19. Efficient k⋅p method for the calculation of total energy and electronic density of states

    OpenAIRE

    Iannuzzi, Marcella; Parrinello, Michele

    2001-01-01

    An efficient method for calculating the electronic structure in large systems with a fully converged BZ sampling is presented. The method is based on a k.p-like approximation developed in the framework of the density functional perturbation theory. The reliability and efficiency of the method are demostrated in test calculations on Ar and Si supercells

  20. On line portal imaging

    International Nuclear Information System (INIS)

    Munro, Peter

    1996-01-01

    Purpose/Objective: The purpose of this presentation is to examine the various imaging devices that have been developed for portal imaging; describe some of the image registration methods that have been developed to determine geometric errors quantitatively; discuss some of the ways that portal imaging has been incorporated into routine clinical practice; describe quality assurance procedures for these devices, and discuss the use of portal imaging devices for dosimetry applications. Discussion: Verification of patient positioning has always been an important aspect of external beam radiation therapy. Over the past decade many portal imaging devices have been developed by individual investigators and most accelerator manufacturers now offer 'on-line' portal imaging systems. The commercial devices can be classified into three categories: T.V. camera-based systems, liquid ionisation chamber systems, and amorphous silicon systems. Many factors influence the quality of images generated by these portal imaging systems. These include factors which are unavoidable (e.g., low subject contrast), factors which depend upon the individual imaging device forming the image (e.g., dose utilisation, spatial resolution) as well as factors which depend upon the characteristics of the linear accelerator irradiating the imaging system (x-ray source size, image magnification). The characteristics of individual imaging systems, such as spatial resolution, temporal response, and quantum utilisation will be discussed. One of the major advantages of on-line portal imaging is that many quantitative techniques have been developed to detect errors in patient positioning. The general approach is to register anatomic structures on a portal image with the same structures on a digitized simulator film. Once the anatomic structures have been registered, any discrepancies in the position of the patient can be identified. However, the task is not nearly as straight-forward as it sounds. One problem

  1. Portal Environment in Today’s Business

    OpenAIRE

    Aldubaikhi, Ammar

    2015-01-01

    Companies can get benefits from new business models as they can have better and efficient collaboration system and this can be derived from the discussed application in this paper. Companies that easily personalize the SAP enterprise portal are more productive and this reflects their interests in business

  2. Efikasnost sistema PVO u uslovima elektronskih dejstava / Efficiency of antiaircraft system in electronic warfare

    Directory of Open Access Journals (Sweden)

    Vladimir V. Šepec

    2007-01-01

    Full Text Available U radu je primenjena teorija masovnog opsluživanja u analizi efikasnosti sistema protivvazduhoplovne odbrane (sistema PVO u uslovima elektronskih dejstava protivnika. Prikazan je model za ocenu efikasnosti sistema PVO i predstavljeni su izrazi za procenu efikasnosti sistema PVO u uslovima elektronskih dejstava. / In this article the theory of mass servicing is used in the analysis of efficiency of antiaircraft system in the conditions of electronic warfare. The model for analysis of the antiaircraft system efficiency has been shown and formulas for qualitative analysis of antiaircraft system efficiency have been presented in the conditions of electronic warfare.

  3. Modulation transfer function and detective quantum efficiency of electron bombarded charge coupled device detector for low energy electrons

    International Nuclear Information System (INIS)

    Horacek, Miroslav

    2005-01-01

    The use of a thinned back-side illuminated charge coupled device chip as two-dimensional sensor working in direct electron bombarded mode at optimum energy of the incident signal electrons is demonstrated and the measurements of the modulation transfer function (MTF) and detective quantum efficiency (DQE) are described. The MTF was measured for energy of electrons 4 keV using an edge projection method and a stripe projection method. The decrease of the MTF for a maximum spatial frequency of 20.8 cycles/mm, corresponding to the pixel size 24x24 μm, is 0.75≅-2.5 dB, and it is approximately the same for both horizontal and vertical directions. DQE was measured using an empty image and the mixing factor method. Empty images were acquired for energies of electrons from 2 to 5 keV and for various doses, ranging from nearly dark image to a nearly saturated one. DQE increases with increasing energy of bombarded electrons and reaches 0.92 for electron energy of 5 keV. For this energy the detector will be used for the angle- and energy-selective detection of signal electrons in the scanning low energy electron microscope

  4. Efficiency calibration of electron spectrometers by the help of standard spectrum

    International Nuclear Information System (INIS)

    Toth, J.; Cserny, I.; Varga, D.; Koever, I.; Toekesi, K.

    2004-01-01

    Complete text of publication follows. For studying thin films and surface nanostructures quantitative analytical applications of electron spectroscopic techniques have a great importance. The most frequently used techniques are XPS, XAES and AES in quantitative surface electron spectroscopy. Applying these techniques changes in the detection efficiency vs. electron kinetic energy change the measured electron peak intensity ratios and in this way the neglect of the energy dependence of the spectrometer efficiency can influence surface atomic concentrations derived. The importance of the precise determination of the atomic concentrations is very crucial, especially in the determination of non-destructive depth profiles by the help of AR-XPS in which small changes in the relative concentrations can change dramatically the concentration depth profiles of a few nanometer depth ranges. In the present study the REELS technique was used to determine the relative detection efficiency by the help of a standard spectrum measured on the surface of fine microcrystalline Cu specimen. The experimental relative efficiency curves vs. electron kinetic energy were compared to the calculated efficiency curve. The efficiency calibration is discussed from the point of view of quantitative XPS, AR- XPS, AES and from the point of view of IMFP determination by XPS. The work was supported by the Hungarian National Science Foundation, OTKAT038016. For the Cu specimen and the standard spectrum the authors are indebted to the Sur- face Analysis Society of Japan, to Dr. Shigeo Tanuma and Professor Keisuke Goto (NIT). (author)

  5. Efficient, Broadband and Wide-Angle Hot-Electron Transduction using Metal-Semiconductor Hyperbolic Metamaterials

    KAUST Repository

    Sakhdari, Maryam

    2016-05-20

    Hot-electron devices are emerging as promising candidates for the transduction of optical radiation into electrical current, as they enable photodetection and solar/infrared energy harvesting at sub-bandgap wavelengths. Nevertheless, poor photoconversion quantum yields and low bandwidth pose fundamental challenge to fascinating applications of hot-electron optoelectronics. Based on a novel hyperbolic metamaterial (HMM) structure, we theoretically propose a vertically-integrated hot-electron device that can efficiently couple plasmonic excitations into electron flows, with an external quantum efficiency approaching the physical limit. Further, this metamaterial-based device can have a broadband and omnidirectional response at infrared and visible wavelengths. We believe that these findings may shed some light on designing practical devices for energy-efficient photodetection and energy harvesting beyond the bandgap spectral limit.

  6. Meaningful Use of a Confidential Adolescent Patient Portal.

    Science.gov (United States)

    Thompson, Lindsay A; Martinko, Thomas; Budd, Pamela; Mercado, Rebeccah; Schentrup, Anzeela M

    2016-02-01

    To design and evaluate the usage of an adolescent patient portal specifically adapted for adolescent health care needs that also satisfied institutional meaningful use guidelines regarding electronic health records. Key stakeholders at one academic health care center adopted an online portal and opted to designate a patient portal specifically for adolescents to maximize confidentiality in compliance with state privacy laws. This study analyzed aggregate electronic health record data of adolescents' (ages 12-17.9 years) uptake, usage, and functionality of this portal and compared it to parent portal usage for younger children (ages 0-11 years). Differences in means were calculated using paired t tests. The portal was used similarly between parents of young children and adolescents, with almost 1,000 enrollees in each group from September 1, 2012 to March 31, 2015. There were no gender differences in enrollment. Adolescents were less likely than parents of younger children to review appointments (73% vs. 85%), laboratory tests (67% vs. 79%), problem lists (40% vs. 78%), or allergies (45% vs. 77%, all p values adolescents sent 1,397 confidential messages. Institutional decisions for implementing meaningful use requirements can align with goals of adolescent health. Patient portals can enhance adolescent health care quality and adolescents readily use a confidential portal. Implementation of meaningful use requirements should be checked against adolescent health care needs to maximize confidentiality and promote health communication. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  7. USAID Business/Partner to Government Transaction Portal

    Data.gov (United States)

    US Agency for International Development — This project expands on the FY12 external facing portal implementation and leverages the Identity Management solution framework to provide greater efficiency for...

  8. Extrahepatic portal hypertension in childhood

    International Nuclear Information System (INIS)

    Takehara, Hiroo; Komi, Nobuhiko; Goh, Masahiro; Yoshida, Sadahiro; Kameoka, Kazuhiro; Hino, Masao; Sui, Osamu

    1986-01-01

    Four pediatric patients with extrahepatic portal hypertension had undergone portography and computerized radionuclide angiography in order to examine shape of portal system and to evaluate hepatic blood flow before and aftersurgical treatment. In all patients, cavernous transformation of portal system was demonstrated by portography, and in one of them spontaneous splenorenal shunt occurred. In 3 of them, who underwent esophageal transsection combined with paraesophagogastric devascularization and splenectomy, so-called direct operation, increase of portal blood flow was revealed by computerized radionuclide angiography. It is suggested that direct operation increasing portal blood flow after surgery is effective in treating extrahepatic portal hypertension in childhood. (author)

  9. Portal monitor evaluation and test procedure

    International Nuclear Information System (INIS)

    Johnson, L.O.; Gupta, V.P.; Stevenson, R.L.; Rich, B.L.

    1983-10-01

    The purpose was to develop techniques and procedures to allow users to measure performance and sensitivity of portal monitors. Additionally, a methodology was developed to assist users in optimizing monitor performance. The two monitors tested utilized thin-window gas-flow proportional counters sensitive to beta and gamma radiation. Various tests were performed: a) background count rate and the statistical variability, b) detector efficiency at different distances, c) moving source sensitivity for various size sources and speeds, and d) false alarm rates at different background levels. A model was developed for the moving source measurements to compare the experimental data with measured results, and to test whether it is possible to adequately model the behavior of a portal monitor's response to a moving source. The model results were compared with the actual test results. A procedure for testing portal monitors is also given. 1 reference, 9 figures, 8 tables

  10. On line portal imaging

    International Nuclear Information System (INIS)

    Munro, Peter

    1997-01-01

    Purpose/Objective: The purpose of this presentation is to examine the various imaging devices that have been developed for portal imaging, describe some of the image registration methods that have been developed to determine geometric errors quantitatively, and discuss how portal imaging has been incorporated into clinical practice. Discussion: Verification of patient positioning has always been an important aspect of external beam radiation therapy. Over the past decade many portal imaging devices have been developed by individual investigators and most accelerator manufacturers now offer 'on-line' portal imaging systems. The commercial devices include T.V. camera-based systems, liquid ionisation chamber systems, and shortly, flat panel systems. The characteristics of these imaging systems will be discussed. In addition, other approaches such as the use of kilovoltage x-ray sources, video monitoring, and ultrasound have been proposed for improving patient positioning. Some of the advantages of these approaches will be discussed. One of the major advantages of on-line portal imaging is that many quantitative techniques have been developed to detect errors in patient positioning. The general approach is to register anatomic structures on a portal image with the same structures on a digitized simulator film. Once the anatomic structures have been registered, any discrepancies in the position of the patient can be identified. One problem is finding a common frame of reference for the simulator and portal images, since the location of the radiation field within the pixel matrix may differ for the two images. As a result, a common frame of reference has to be established before the anatomic structures in the images can be registered - generally by registering radiation field edges identified in the simulator and portal images. In addition, distortions in patient geometry or rotations out of the image plane can confound the image registration techniques. Despite the

  11. Portal venous stent placement for treatment of portal hypertension caused by benign main portal vein stenosis.

    Science.gov (United States)

    Shan, Hong; Xiao, Xiang-Sheng; Huang, Ming-Sheng; Ouyang, Qiang; Jiang, Zai-Bo

    2005-06-07

    To evaluate the value of endovascular stent in the treatment of portal hypertension caused by benign main portal vein stenosis. Portal vein stents were implanted in six patients with benign main portal vein stenosis (inflammatory stenosis in three cases, postprocedure of liver transplantation in another three cases). Changes in portal vein pressure, portal vein patency, relative clinical symptoms, complications, and survival were evaluated. Six metallic stents were successfully placed across the portal vein stenotic or obstructive lesions in six patients. Mean portal venous pressure decreased significantly after stent implantation from (37.3+/-4.7) cm H(2)O to (18.0+/-1.9) cm H(2)O. The portal blood flow restored and the symptoms caused by portal hypertension were eliminated. There were no severe procedure-related complications. The patients were followed up for 1-48 mo. The portal vein remained patent during follow-up. All patients survived except for one patient who died of other complications of liver transplantation. Percutaneous portal vein stent placement for the treatment of portal hypertension caused by benign main portal vein stenosis is safe and effective.

  12. Electron efficiency measurements with the ATLAS detector using 2012 LHC proton-proton collision data

    CERN Document Server

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Havranek, Miroslav; Hawkes, Christopher; Hawkings, Richard John; Hayakawa, Daiki; Hayden, Daniel; Hays, Chris; Hays, Jonathan Michael; Hayward, Helen; Haywood, Stephen; Head, Simon; Heck, Tobias; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heim, Timon; Heinemann, Beate; Heinrich, Jochen Jens; Heinrich, Lukas; Heinz, Christian; Hejbal, Jiri; Helary, Louis; Hellman, Sten; Helsens, Clement; Henderson, James; Henderson, Robert; Heng, Yang; Henkelmann, Steffen; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Herbert, Geoffrey Henry; Herde, Hannah; Herget, Verena; Hernández Jiménez, Yesenia; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Hetherly, Jeffrey Wayne; Higón-Rodriguez, Emilio; Hill, Ewan; Hill, John; Hiller, Karl Heinz; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hirose, Minoru; Hirschbuehl, Dominic; Hladik, Ondrej; Hoad, Xanthe; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoenig, Friedrich; Hohn, David; Holmes, Tova Ray; Homann, Michael; Honda, Shunsuke; Honda, Takuya; Hong, Tae Min; Hooberman, Benjamin Henry; Hopkins, Walter; Horii, Yasuyuki; Horton, Arthur James; Hostachy, Jean-Yves; Hou, Suen; Hoummada, Abdeslam; Howarth, James; Hoya, Joaquin; Hrabovsky, Miroslav; Hristova, Ivana; Hrivnac, Julius; Hryn'ova, Tetiana; Hrynevich, Aliaksei; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Hu, Qipeng; Hu, Shuyang; Huang, Yanping; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Huhtinen, Mika; Huo, Peng; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibragimov, Iskander; Iconomidou-Fayard, Lydia; Ideal, Emma; Iengo, Paolo; Igonkina, Olga; Iizawa, Tomoya; Ikegami, Yoichi; Ikeno, Masahiro; Ilchenko, Yuriy; Iliadis, Dimitrios; Ilic, Nikolina; Introzzi, Gianluca; Ioannou, Pavlos; Iodice, Mauro; Iordanidou, Kalliopi; Ippolito, Valerio; Ishijima, Naoki; Ishino, Masaya; Ishitsuka, Masaki; Issever, Cigdem; Istin, Serhat; Ito, Fumiaki; Iturbe Ponce, Julia Mariana; Iuppa, Roberto; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jabbar, Samina; Jackson, Brett; Jackson, Paul; Jain, Vivek; Jakobi, Katharina Bianca; Jakobs, Karl; Jakobsen, Sune; Jakoubek, Tomas; Jamin, David Olivier; Jana, Dilip; Jansky, Roland; Janssen, Jens; Janus, Michel; Janus, Piotr Andrzej; Jarlskog, Göran; Javadov, Namig; Javůrek, Tomáš; Javurkova, Martina; Jeanneau, Fabien; Jeanty, Laura; Jejelava, Juansher; Jeng, Geng-yuan; Jenni, Peter; Jeske, Carl; Jézéquel, Stéphane; Ji, Haoshuang; Jia, Jiangyong; Jiang, Hai; Jiang, Yi; Jiang, Zihao; Jiggins, Stephen; Jimenez Pena, Javier; Jin, Shan; Jinaru, Adam; Jinnouchi, Osamu; Jivan, Harshna; Johansson, Per; Johns, Kenneth; Johnson, Christian; Johnson, William Joseph; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Sarah; Jones, Tim; Jongmanns, Jan; Jorge, Pedro; Jovicevic, Jelena; Ju, Xiangyang; Juste Rozas, Aurelio; Köhler, Markus Konrad; Kaczmarska, Anna; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kahn, Sebastien Jonathan; Kaji, Toshiaki; Kajomovitz, Enrique; Kalderon, Charles William; Kaluza, Adam; Kama, Sami; Kamenshchikov, Andrey; Kanaya, Naoko; Kaneti, Steven; Kanjir, Luka; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kaplan, Laser Seymour; Kapliy, Anton; Kar, Deepak; Karakostas, Konstantinos; Karamaoun, Andrew; Karastathis, Nikolaos; Kareem, Mohammad Jawad; Karentzos, Efstathios; Karnevskiy, Mikhail; Karpov, Sergey; Karpova, Zoya; Karthik, Krishnaiyengar; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kasahara, Kota; Kashif, Lashkar; Kass, Richard; Kastanas, Alex; Kataoka, Yousuke; Kato, Chikuma; Katre, Akshay; Katzy, Judith; Kawade, Kentaro; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kazanin, Vassili; Keeler, Richard; Kehoe, Robert; Keller, John; Kempster, Jacob Julian; Keoshkerian, Houry; Kepka, Oldrich; Kerševan, Borut Paul; Kersten, Susanne; Keyes, Robert; Khader, Mazin; Khalil-zada, Farkhad; Khanov, Alexander; Kharlamov, Alexey; Kharlamova, Tatyana; Khoo, Teng Jian; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kido, Shogo; Kilby, Callum; Kim, Hee Yeun; Kim, Shinhong; Kim, Young-Kee; Kimura, Naoki; Kind, Oliver Maria; King, Barry; King, Matthew; Kirk, Julie; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kiss, Florian; Kiuchi, Kenji; Kivernyk, Oleh; Kladiva, Eduard; Klein, Matthew Henry; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klioutchnikova, Tatiana; Kluge, Eike-Erik; Kluit, Peter; Kluth, Stefan; Knapik, Joanna; Kneringer, Emmerich; Knoops, Edith; Knue, Andrea; Kobayashi, Aine; Kobayashi, Dai; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Koffas, Thomas; Koffeman, Els; Köhler, Nicolas Maximilian; Koi, Tatsumi; Kolanoski, Hermann; Kolb, Mathis; Koletsou, Iro; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Kondrashova, Nataliia; Köneke, Karsten; König, Adriaan; Kono, Takanori; Konoplich, Rostislav; Konstantinidis, Nikolaos; Kopeliansky, Revital; Koperny, Stefan; Kopp, Anna Katharina; Korcyl, Krzysztof; Kordas, Kostantinos; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Kortner, Oliver; Kortner, Sandra; Kosek, Tomas; Kostyukhin, Vadim; Kotwal, Ashutosh; Koulouris, Aimilianos; Kourkoumeli-Charalampidi, Athina; Kourkoumelis, Christine; Kouskoura, Vasiliki; Kowalewska, Anna Bozena; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozakai, Chihiro; Kozanecki, Witold; Kozhin, Anatoly; Kramarenko, Viktor; Kramberger, Gregor; Krasnopevtsev, Dimitriy; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kravchenko, Anton; Kretz, Moritz; Kretzschmar, Jan; Kreutzfeldt, Kristof; Krieger, Peter; Krizka, Karol; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Krumnack, Nils; Kruse, Mark; Kruskal, Michael; Kubota, Takashi; Kucuk, Hilal; Kuday, Sinan; Kuechler, Jan Thomas; Kuehn, Susanne; Kugel, Andreas; Kuger, Fabian; Kuhl, Thorsten; Kukhtin, Victor; Kukla, Romain; Kulchitsky, Yuri; Kuleshov, Sergey; Kuna, Marine; Kunigo, Takuto; Kupco, Alexander; Kuprash, Oleg; Kurashige, Hisaya; Kurchaninov, Leonid; Kurochkin, Yurii; Kurth, Matthew Glenn; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; Kwan, Tony; Kyriazopoulos, Dimitrios; La Rosa, Alessandro; La Rosa Navarro, Jose Luis; La Rotonda, Laura; Lacasta, Carlos; Lacava, Francesco; Lacey, James; Lacker, Heiko; Lacour, Didier; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Lammers, Sabine; Lampl, Walter; Lançon, Eric; Landgraf, Ulrich; Landon, Murrough; Lanfermann, Marie Christine; Lang, Valerie Susanne; Lange, J örn Christian; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Lanza, Agostino; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Lasagni Manghi, Federico; Lassnig, Mario; Laurelli, Paolo; Lavrijsen, Wim; Law, Alexander; Laycock, Paul; Lazovich, Tomo; Lazzaroni, Massimo; Le, Brian; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Quilleuc, Eloi; LeBlanc, Matthew Edgar; LeCompte, Thomas; Ledroit-Guillon, Fabienne; Lee, Claire Alexandra; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Benoit; Lefebvre, Guillaume; Lefebvre, Michel; Legger, Federica; Leggett, Charles; Lehan, Allan; Lehmann Miotto, Giovanna; Lei, Xiaowen; Leight, William Axel; Leister, Andrew Gerard; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Lemmer, Boris; Leney, Katharine; Lenz, Tatjana; Lenzi, Bruno; Leone, Robert; Leone, Sandra; Leonidopoulos, Christos; Leontsinis, Stefanos; Lerner, Giuseppe; Leroy, Claude; Lesage, Arthur; Lester, Christopher; Lester, Christopher Michael; Levchenko, Mikhail; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Levy, Mark; Lewis, Dave; Leyton, Michael; Li, Bing; Li, Changqiao; Li, Haifeng; Li, Lei; Li, Liang; Li, Qi; Li, Shu; Li, Xingguo; Li, Yichen; Liang, Zhijun; Liberti, Barbara; Liblong, Aaron; Lichard, Peter; Lie, Ki; Liebal, Jessica; Liebig, Wolfgang; Limosani, Antonio; Lin, Simon; Lin, Tai-Hua; Lindquist, Brian Edward; Lionti, Anthony Eric; Lipeles, Elliot; Lipniacka, Anna; Lisovyi, Mykhailo; Liss, Tony; Lister, Alison; Litke, Alan; Liu, Bo; Liu, Dong; Liu, Hao; Liu, Hongbin; Liu, Jian; Liu, Jianbei; Liu, Kun; Liu, Lulu; Liu, Minghui; Liu, Yanlin; Liu, Yanwen; Livan, Michele; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lo Sterzo, Francesco; Lobodzinska, Ewelina Maria; Loch, Peter; Loebinger, Fred; Loew, Kevin Michael; Loginov, Andrey; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Long, Brian Alexander; Long, Jonathan David; Long, Robin Eamonn; Longo, Luigi; Looper, Kristina Anne; Lopez, Jorge; Lopez Mateos, David; Lopez Paredes, Brais; Lopez Paz, Ivan; Lopez Solis, Alvaro; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Lösel, Philipp Jonathan; Lou, XinChou; Lounis, Abdenour; Love, Jeremy; Love, Peter; Lu, Haonan; Lu, Nan; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Luedtke, Christian; Luehring, Frederick; Lukas, Wolfgang; Luminari, Lamberto; Lundberg, Olof; Lund-Jensen, Bengt; Luzi, Pierre Marc; Lynn, David; Lysak, Roman; Lytken, Else; Lyubushkin, Vladimir; Ma, Hong; Ma, Lian Liang; Ma, Yanhui; Maccarrone, Giovanni; Macchiolo, Anna; Macdonald, Calum Michael; Maček, Boštjan; Machado Miguens, Joana; Madaffari, Daniele; Madar, Romain; Maddocks, Harvey Jonathan; Mader, Wolfgang; Madsen, Alexander; Maeda, Junpei; Maeland, Steffen; Maeno, Tadashi; Maevskiy, Artem; Magradze, Erekle; Mahlstedt, Joern; Maiani, Camilla; Maidantchik, Carmen; Maier, Andreas Alexander; Maier, Thomas; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Malaescu, Bogdan; Malecki, Pawel; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Claire; Maltezos, Stavros; Malyukov, Sergei; Mamuzic, Judita; Mancini, Giada; Mandelli, Luciano; Mandić, Igor; Maneira, José; Manhaes de Andrade Filho, Luciano; Manjarres Ramos, Joany; Mann, Alexander; Manousos, Athanasios; Mansoulie, Bruno; Mansour, Jason Dhia; Mantifel, Rodger; Mantoani, Matteo; Manzoni, Stefano; Mapelli, Livio; Marceca, Gino; March, Luis; Marchiori, Giovanni; Marcisovsky, Michal; Marjanovic, Marija; Marley, Daniel; Marroquim, Fernando; Marsden, Stephen Philip; Marshall, Zach; Marti-Garcia, Salvador; Martin, Brian Thomas; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martinez, Mario; Martinez Outschoorn, Verena; Martin-Haugh, Stewart; Martoiu, Victor Sorin; Martyniuk, Alex; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massa, Lorenzo; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Mättig, Peter; Mattmann, Johannes; Maurer, Julien; Maxfield, Stephen; Maximov, Dmitriy; Mazini, Rachid; Maznas, Ioannis; Mazza, Simone Michele; Mc Fadden, Neil Christopher; Mc Goldrick, Garrin; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McClymont, Laurie; McDonald, Emily; Mcfayden, Josh; Mchedlidze, Gvantsa; McMahon, Steve; McPherson, Robert; Medinnis, Michael; Meehan, Samuel; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meineck, Christian; Meirose, Bernhard; Melini, Davide; Mellado Garcia, Bruce Rafael; Melo, Matej; Meloni, Federico; Menary, Stephen Burns; Meng, Lingxin; Meng, Xiangting; Mengarelli, Alberto; Menke, Sven; Meoni, Evelin; Mergelmeyer, Sebastian; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Meyer Zu Theenhausen, Hanno; Miano, Fabrizio; Middleton, Robin; Miglioranzi, Silvia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Milesi, Marco; Milic, Adriana; Miller, David; Mills, Corrinne; Milov, Alexander; Milstead, David; Minaenko, Andrey; Minami, Yuto; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Minegishi, Yuji; Ming, Yao; Mir, Lluisa-Maria; Mistry, Khilesh; Mitani, Takashi; Mitrevski, Jovan; Mitsou, Vasiliki A; Miucci, Antonio; Miyagawa, Paul; Mizukami, Atsushi; Mjörnmark, Jan-Ulf; Mlynarikova, Michaela; Moa, Torbjoern; Mochizuki, Kazuya; Mogg, Philipp; Mohapatra, Soumya; Molander, Simon; Moles-Valls, Regina; Monden, Ryutaro; Mondragon, Matthew Craig; Mönig, Klaus; Monk, James; Monnier, Emmanuel; Montalbano, Alyssa; Montejo Berlingen, Javier; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Morange, Nicolas; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Morgenstern, Stefanie; Mori, Daniel; Mori, Tatsuya; Morii, Masahiro; Morinaga, Masahiro; Morisbak, Vanja; Moritz, Sebastian; Morley, Anthony Keith; Mornacchi, Giuseppe; Morris, John; Morvaj, Ljiljana; Moschovakos, Paris; Mosidze, Maia; Moss, Harry James; Moss, Josh; Motohashi, Kazuki; Mount, Richard; Mountricha, Eleni; Moyse, Edward; Muanza, Steve; Mudd, Richard; Mueller, Felix; Mueller, James; Mueller, Ralph Soeren Peter; Mueller, Thibaut; Muenstermann, Daniel; Mullen, Paul; Mullier, Geoffrey; Munoz Sanchez, Francisca Javiela; Murillo Quijada, Javier Alberto; Murray, Bill; Musheghyan, Haykuhi; Muškinja, Miha; Myagkov, Alexey; Myska, Miroslav; Nachman, Benjamin Philip; Nackenhorst, Olaf; Nagai, Koichi; Nagai, Ryo; Nagano, Kunihiro; Nagasaka, Yasushi; Nagata, Kazuki; Nagel, Martin; Nagy, Elemer; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Naranjo Garcia, Roger Felipe; Narayan, Rohin; Narrias Villar, Daniel Isaac; Naryshkin, Iouri; Naumann, Thomas; Navarro, Gabriela; Nayyar, Ruchika; Neal, Homer; Nechaeva, Polina; Neep, Thomas James; Negri, Andrea; Negrini, Matteo; Nektarijevic, Snezana; Nellist, Clara; Nelson, Andrew; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neumann, Manuel; Neves, Ricardo; Nevski, Pavel; Newman, Paul; Nguyen, Duong Hai; Nguyen Manh, Tuan; Nickerson, Richard; Nicolaidou, Rosy; Nielsen, Jason; Nikolaenko, Vladimir; Nikolic-Audit, Irena; Nikolopoulos, Konstantinos; Nilsen, Jon Kerr; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nisius, Richard; Nobe, Takuya; Nomachi, Masaharu; Nomidis, Ioannis; Nooney, Tamsin; Norberg, Scarlet; Nordberg, Markus; Norjoharuddeen, Nurfikri; Novgorodova, Olga; Nowak, Sebastian; Nozaki, Mitsuaki; Nozka, Libor; Ntekas, Konstantinos; Nurse, Emily; Nuti, Francesco; O'grady, Fionnbarr; O'Neil, Dugan; O'Rourke, Abigail Alexandra; O'Shea, Val; Oakham, Gerald; Oberlack, Horst; Obermann, Theresa; Ocariz, Jose; Ochi, Atsuhiko; Ochoa, Ines; Ochoa-Ricoux, Juan Pedro; Oda, Susumu; Odaka, Shigeru; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohman, Henrik; Oide, Hideyuki; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Oleiro Seabra, Luis Filipe; Olivares Pino, Sebastian Andres; Oliveira Damazio, Denis; Olszewski, Andrzej; Olszowska, Jolanta; Onofre, António; Onogi, Kouta; Onyisi, Peter; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlando, Nicola; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Otero y Garzon, Gustavo; Otono, Hidetoshi; Ouchrif, Mohamed; Ould-Saada, Farid; Ouraou, Ahmimed; Oussoren, Koen Pieter; Ouyang, Qun; Owen, Mark; Owen, Rhys Edward; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pachal, Katherine; Pacheco Pages, Andres; Pacheco Rodriguez, Laura; Padilla Aranda, Cristobal; Pagan Griso, Simone; Paganini, Michela; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Palazzo, Serena; Palestini, Sandro; Palka, Marek; Pallin, Dominique; Panagiotopoulou, Evgenia; Panagoulias, Ilias; Pandini, Carlo Enrico; Panduro Vazquez, William; Pani, Priscilla; Panitkin, Sergey; Pantea, Dan; Paolozzi, Lorenzo; Papadopoulou, Theodora; Papageorgiou, Konstantinos; Paramonov, Alexander; Paredes Hernandez, Daniela; Parker, Adam Jackson; Parker, Michael Andrew; Parker, Kerry Ann; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pascuzzi, Vincent; Pasqualucci, Enrico; Passaggio, Stefano; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Pater, Joleen; Pauly, Thilo; Pearce, James; Pearson, Benjamin; Pedersen, Lars Egholm; Pedraza Lopez, Sebastian; Pedro, Rute; Peleganchuk, Sergey; Penc, Ondrej; Peng, Cong; Peng, Haiping; Penwell, John; Peralva, Bernardo; Perego, Marta Maria; Perepelitsa, Dennis; Perez Codina, Estel; Perini, Laura; Pernegger, Heinz; Perrella, Sabrina; Peschke, Richard; Peshekhonov, Vladimir; Peters, Krisztian; Peters, Yvonne; Petersen, Brian; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petroff, Pierre; Petrolo, Emilio; Petrov, Mariyan; Petrucci, Fabrizio; Pettersson, Nora Emilia; Peyaud, Alan; Pezoa, Raquel; Phillips, Peter William; Piacquadio, Giacinto; Pianori, Elisabetta; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Pickering, Mark Andrew; Piegaia, Ricardo; Pilcher, James; Pilkington, Andrew; Pin, Arnaud Willy J; Pinamonti, Michele; Pinfold, James; Pingel, Almut; Pires, Sylvestre; Pirumov, Hayk; Pitt, Michael; Plazak, Lukas; Pleier, Marc-Andre; Pleskot, Vojtech; Plotnikova, Elena; Pluth, Daniel; Poettgen, Ruth; Poggioli, Luc; Pohl, David-leon; Polesello, Giacomo; Poley, Anne-luise; Policicchio, Antonio; Polifka, Richard; Polini, Alessandro; Pollard, Christopher Samuel; Polychronakos, Venetios; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Poppleton, Alan; Pospisil, Stanislav; Potamianos, Karolos; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Pozo Astigarraga, Mikel Eukeni; Pralavorio, Pascal; Pranko, Aliaksandr; Prell, Soeren; Price, Darren; Price, Lawrence; Primavera, Margherita; Prince, Sebastien; Prokofiev, Kirill; Prokoshin, Fedor; Protopopescu, Serban; Proudfoot, James; Przybycien, Mariusz; Puddu, Daniele; Purohit, Milind; Puzo, Patrick; Qian, Jianming; Qin, Gang; Qin, Yang; Quadt, Arnulf; Quayle, William; Queitsch-Maitland, Michaela; Quilty, Donnchadha; Raddum, Silje; Radeka, Veljko; Radescu, Voica; Radhakrishnan, Sooraj Krishnan; Radloff, Peter; Rados, Pere; Ragusa, Francesco; Rahal, Ghita; Raine, John Andrew; Rajagopalan, Srinivasan; Rammensee, Michael; Rangel-Smith, Camila; Ratti, Maria Giulia; Rauch, Daniel; Rauscher, Felix; Rave, Stefan; Ravenscroft, Thomas; Ravinovich, Ilia; Raymond, Michel; Read, Alexander Lincoln; Readioff, Nathan Peter; Reale, Marilea; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reed, Robert; Reeves, Kendall; Rehnisch, Laura; Reichert, Joseph; Reiss, Andreas; Rembser, Christoph; Ren, Huan; Rescigno, Marco; Resconi, Silvia; Resseguie, Elodie Deborah; Rezanova, Olga; Reznicek, Pavel; Rezvani, Reyhaneh; Richter, Robert; Richter, Stefan; Richter-Was, Elzbieta; Ricken, Oliver; Ridel, Melissa; Rieck, Patrick; Riegel, Christian Johann; Rieger, Julia; Rifki, Othmane; Rijssenbeek, Michael; Rimoldi, Adele; Rimoldi, Marco; Rinaldi, Lorenzo; Ristić, Branislav; Ritsch, Elmar; Riu, Imma; Rizatdinova, Flera; Rizvi, Eram; Rizzi, Chiara; Roberts, Rhys Thomas; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Roda, Chiara; Rodina, Yulia; Rodriguez Perez, Andrea; Rodriguez Rodriguez, Daniel; Roe, Shaun; Rogan, Christopher Sean; Røhne, Ole; Roloff, Jennifer; Romaniouk, Anatoli; Romano, Marino; Romano Saez, Silvestre Marino; Romero Adam, Elena; Rompotis, Nikolaos; Ronzani, Manfredi; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Peyton; Rosien, Nils-Arne; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rosten, Jonatan; Rosten, Rachel; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Rozanov, Alexandre; Rozen, Yoram; Ruan, Xifeng; Rubbo, Francesco; Rudolph, Matthew Scott; Rühr, Frederik; Ruiz-Martinez, Aranzazu; Rurikova, Zuzana; Rusakovich, Nikolai; Ruschke, Alexander; Russell, Heather; Rutherfoord, John; Ruthmann, Nils; Ryabov, Yury; Rybar, Martin; Rybkin, Grigori; Ryu, Soo; Ryzhov, Andrey; Rzehorz, Gerhard Ferdinand; Saavedra, Aldo; Sabato, Gabriele; Sacerdoti, Sabrina; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Saha, Puja; Sahinsoy, Merve; Saimpert, Matthias; Saito, Tomoyuki; Sakamoto, Hiroshi; Sakurai, Yuki; Salamanna, Giuseppe; Salamon, Andrea; Salazar Loyola, Javier Esteban; Salek, David; Sales De Bruin, Pedro Henrique; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sammel, Dirk; Sampsonidis, Dimitrios; Sánchez, Javier; Sanchez Martinez, Victoria; Sanchez Pineda, Arturo Rodolfo; Sandaker, Heidi; Sandbach, Ruth Laura; Sandhoff, Marisa; Sandoval, Carlos; Sankey, Dave; Sannino, Mario; Sansoni, Andrea; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Santoyo Castillo, Itzebelt; Sapp, Kevin; Sapronov, Andrey; Saraiva, João; Sarrazin, Bjorn; Sasaki, Osamu; Sato, Koji; Sauvan, Emmanuel; Savage, Graham; Savard, Pierre; Savic, Natascha; Sawyer, Craig; Sawyer, Lee; Saxon, James; Sbarra, Carla; Sbrizzi, Antonio; Scanlon, Tim; Scannicchio, Diana; Scarcella, Mark; Scarfone, Valerio; Schaarschmidt, Jana; Schacht, Peter; Schachtner, Balthasar Maria; Schaefer, Douglas; Schaefer, Leigh; Schaefer, Ralph; Schaeffer, Jan; Schaepe, Steffen; Schaetzel, Sebastian; Schäfer, Uli; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R Dean; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Schiavi, Carlo; Schier, Sheena; Schillo, Christian; Schioppa, Marco; Schlenker, Stefan; Schmidt-Sommerfeld, Korbinian Ralf; Schmieden, Kristof; Schmitt, Christian; Schmitt, Stefan; Schmitz, Simon; Schneider, Basil; Schnoor, Ulrike; Schoeffel, Laurent; Schoening, Andre; Schoenrock, Bradley Daniel; Schopf, Elisabeth; Schott, Matthias; Schouwenberg, Jeroen; Schovancova, Jaroslava; Schramm, Steven; Schreyer, Manuel; Schuh, Natascha; Schulte, Alexandra; Schultens, Martin Johannes; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwartzman, Ariel; Schwarz, Thomas Andrew; Schweiger, Hansdieter; Schwemling, Philippe; Schwienhorst, Reinhard; Schwindling, Jerome; Schwindt, Thomas; Sciolla, Gabriella; Scuri, Fabrizio; Scutti, Federico; Searcy, Jacob; Seema, Pienpen; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Sekhon, Karishma; Sekula, Stephen; Seliverstov, Dmitry; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Serre, Thomas; Sessa, Marco; Seuster, Rolf; Severini, Horst; Sfiligoj, Tina; Sforza, Federico; Sfyrla, Anna; Shabalina, Elizaveta; Shaikh, Nabila Wahab; Shan, Lianyou; Shang, Ruo-yu; Shank, James; Shapiro, Marjorie; Shatalov, Pavel; Shaw, Kate; Shaw, Savanna Marie; Shcherbakova, Anna; Shehu, Ciwake Yusufu; Sherwood, Peter; Shi, Liaoshan; Shimizu, Shima; Shimmin, Chase Owen; Shimojima, Makoto; Shirabe, Shohei; Shiyakova, Mariya; Shmeleva, Alevtina; Shoaleh Saadi, Diane; Shochet, Mel; Shojaii, Seyed Ruhollah; Shope, David Richard; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Sicho, Petr; Sickles, Anne Marie; Sidebo, Per Edvin; Sideras Haddad, Elias; Sidiropoulou, Ourania; Sidorov, Dmitri; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silva, José; Silverstein, Samuel; Simak, Vladislav; Simic, Ljiljana; Simion, Stefan; Simioni, Eduard; Simmons, Brinick; Simon, Dorian; Simon, Manuel; Sinervo, Pekka; Sinev, Nikolai; Sioli, Maximiliano; Siragusa, Giovanni; Siral, Ismet; Sivoklokov, Serguei; Sjölin, Jörgen; Skinner, Malcolm Bruce; Skottowe, Hugh Philip; Skubic, Patrick; Slater, Mark; Slavicek, Tomas; Slawinska, Magdalena; Sliwa, Krzysztof; Slovak, Radim; Smakhtin, Vladimir; Smart, Ben; Smestad, Lillian; Smiesko, Juraj; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smith, Joshua Wyatt; Smith, Matthew; Smith, Russell; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snyder, Ian Michael; Snyder, Scott; Sobie, Randall; Socher, Felix; Soffer, Abner; Soh, Dart-yin; Sokhrannyi, Grygorii; Solans Sanchez, Carlos; Solar, Michael; Soldatov, Evgeny; Soldevila, Urmila; Solodkov, Alexander; Soloshenko, Alexei; Solovyanov, Oleg; Solovyev, Victor; Sommer, Philip; Son, Hyungsuk; Song, Hong Ye; Sood, Alexander; Sopczak, Andre; Sopko, Vit; Sorin, Veronica; Sosa, David; Sotiropoulou, Calliope Louisa; Soualah, Rachik; Soukharev, Andrey; South, David; Sowden, Benjamin; Spagnolo, Stefania; Spalla, Margherita; Spangenberg, Martin; Spanò, Francesco; Sperlich, Dennis; Spettel, Fabian; Spighi, Roberto; Spigo, Giancarlo; Spiller, Laurence Anthony; Spousta, Martin; St Denis, Richard Dante; Stabile, Alberto; Stamen, Rainer; Stamm, Soren; Stanecka, Ewa; Stanek, Robert; Stanescu, Cristian; Stanescu-Bellu, Madalina; Stanitzki, Marcel Michael; Stapnes, Steinar; Starchenko, Evgeny; Stark, Giordon; Stark, Jan; Stark, Simon Holm; Staroba, Pavel; Starovoitov, Pavel; Stärz, Steffen; Staszewski, Rafal; Steinberg, Peter; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoebe, Michael; Stoicea, Gabriel; Stolte, Philipp; Stonjek, Stefan; Stradling, Alden; Straessner, Arno; Stramaglia, Maria Elena; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Stroynowski, Ryszard; Strubig, Antonia; Stucci, Stefania Antonia; Stugu, Bjarne; Styles, Nicholas Adam; Su, Dong; Su, Jun; Suchek, Stanislav; Sugaya, Yorihito; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Siyuan; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Suster, Carl; Sutton, Mark; Suzuki, Shota; Svatos, Michal; Swiatlowski, Maximilian; Swift, Stewart Patrick; Sykora, Ivan; Sykora, Tomas; Ta, Duc; Tackmann, Kerstin; Taenzer, Joe; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takai, Helio; Takashima, Ryuichi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tanaka, Junichi; Tanaka, Masahiro; Tanaka, Reisaburo; Tanaka, Shuji; Tanioka, Ryo; Tannenwald, Benjamin Bordy; Tapia Araya, Sebastian; Tapprogge, Stefan; Tarem, Shlomit; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tashiro, Takuya; Tassi, Enrico; Tavares Delgado, Ademar; Tayalati, Yahya; Taylor, Aaron; Taylor, Geoffrey; Taylor, Pierre Thor Elliot; Taylor, Wendy; Teischinger, Florian Alfred; Teixeira-Dias, Pedro; Temming, Kim Katrin; Temple, Darren; Ten Kate, Herman; Teng, Ping-Kun; Teoh, Jia Jian; Tepel, Fabian-Phillipp; Terada, Susumu; Terashi, Koji; Terron, Juan; Terzo, Stefano; Testa, Marianna; Teuscher, Richard; Theveneaux-Pelzer, Timothée; Thomas, Juergen; Thomas-Wilsker, Joshuha; Thompson, Paul; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Tibbetts, Mark James; Ticse Torres, Royer Edson; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tiouchichine, Elodie; Tipton, Paul; Tisserant, Sylvain; Todome, Kazuki; Todorov, Theodore; Todorova-Nova, Sharka; Tojo, Junji; Tokár, Stanislav; Tokushuku, Katsuo; Tolley, Emma; Tomlinson, Lee; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Tong, Baojia(Tony); Tornambe, Peter; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Trefzger, Thomas; Tricoli, Alessandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Tripiana, Martin; Trischuk, William; Trocmé, Benjamin; Trofymov, Artur; Troncon, Clara; Trottier-McDonald, Michel; Trovatelli, Monica; Truong, Loan; Trzebinski, Maciej; Trzupek, Adam; Tseng, Jeffrey; Tsiareshka, Pavel; Tsipolitis, Georgios; Tsirintanis, Nikolaos; Tsiskaridze, Shota; Tsiskaridze, Vakhtang; Tskhadadze, Edisher; Tsui, Ka Ming; Tsukerman, Ilya; Tsulaia, Vakhtang; Tsuno, Soshi; Tsybychev, Dmitri; Tu, Yanjun; Tudorache, Alexandra; Tudorache, Valentina; Tulbure, Traian Tiberiu; Tuna, Alexander Naip; Tupputi, Salvatore; Turchikhin, Semen; Turgeman, Daniel; Turk Cakir, Ilkay; Turra, Ruggero; Tuts, Michael; Ucchielli, Giulia; Ueda, Ikuo; Ughetto, Michael; Ukegawa, Fumihiko; Unal, Guillaume; Undrus, Alexander; Unel, Gokhan; Ungaro, Francesca; Unno, Yoshinobu; Unverdorben, Christopher; Urban, Jozef; Urquijo, Phillip; Urrejola, Pedro; Usai, Giulio; Usui, Junya; Vacavant, Laurent; Vacek, Vaclav; Vachon, Brigitte; Valderanis, Chrysostomos; Valdes Santurio, Eduardo; Valencic, Nika; Valentinetti, Sara; Valero, Alberto; Valery, Loic; Valkar, Stefan; Valls Ferrer, Juan Antonio; Van Den Wollenberg, Wouter; Van Der Deijl, Pieter; van der Graaf, Harry; van Eldik, Niels; van Gemmeren, Peter; Van Nieuwkoop, Jacobus; van Vulpen, Ivo; van Woerden, Marius Cornelis; Vanadia, Marco; Vandelli, Wainer; Vanguri, Rami; Vaniachine, Alexandre; Vankov, Peter; Vardanyan, Gagik; Vari, Riccardo; Varnes, Erich; Varol, Tulin; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vasquez, Jared Gregory; Vasquez, Gerardo; Vazeille, Francois; Vazquez Schroeder, Tamara; Veatch, Jason; Veeraraghavan, Venkatesh; Veloce, Laurelle Maria; Veloso, Filipe; Veneziano, Stefano; Ventura, Andrea; Venturi, Manuela; Venturi, Nicola; Venturini, Alessio; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Viazlo, Oleksandr; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Vigani, Luigi; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinogradov, Vladimir; Vittori, Camilla; Vivarelli, Iacopo; Vlachos, Sotirios; Vlasak, Michal; Vogel, Marcelo; Vokac, Petr; Volpi, Guido; Volpi, Matteo; von der Schmitt, Hans; von Toerne, Eckhard; Vorobel, Vit; Vorobev, Konstantin; Vos, Marcel; Voss, Rudiger; Vossebeld, Joost; Vranjes, Nenad; Vranjes Milosavljevic, Marija; Vrba, Vaclav; Vreeswijk, Marcel; Vuillermet, Raphael; Vukotic, Ilija; Wagner, Peter; Wagner, Wolfgang; Wahlberg, Hernan; Wahrmund, Sebastian; Wakabayashi, Jun; Walder, James; Walker, Rodney; Walkowiak, Wolfgang; Wallangen, Veronica; Wang, Chao; Wang, Chao; Wang, Fuquan; Wang, Haichen; Wang, Hulin; Wang, Jike; Wang, Jin; Wang, Kuhan; Wang, Rui; Wang, Song-Ming; Wang, Tingting; Wang, Wenxiao; Wanotayaroj, Chaowaroj; Warburton, Andreas; Ward, Patricia; Wardrope, David Robert; Washbrook, Andrew; Watkins, Peter; Watson, Alan; Watson, Miriam; Watts, Gordon; Watts, Stephen; Waugh, Ben; Webb, Samuel; Weber, Michele; Weber, Stefan Wolf; Weber, Stephen; Webster, Jordan S; Weidberg, Anthony; Weinert, Benjamin; Weingarten, Jens; Weiser, Christian; Weits, Hartger; Wells, Phillippa; Wenaus, Torre; Wengler, Thorsten; Wenig, Siegfried; Wermes, Norbert; Werner, Michael David; Werner, Per; Wessels, Martin; Wetter, Jeffrey; Whalen, Kathleen; Whallon, Nikola Lazar; Wharton, Andrew Mark; White, Andrew; White, Martin; White, Ryan; Whiteson, Daniel; Wickens, Fred; Wiedenmann, Werner; Wielers, Monika; Wiglesworth, Craig; Wiik-Fuchs, Liv Antje Mari; Wildauer, Andreas; Wilk, Fabian; Wilkens, Henric George; Williams, Hugh; Williams, Sarah; Willis, Christopher; Willocq, Stephane; Wilson, John; Wingerter-Seez, Isabelle; Winklmeier, Frank; Winston, Oliver James; Winter, Benedict Tobias; Wittgen, Matthias; Wolf, Tim Michael Heinz; Wolff, Robert; Wolter, Marcin Wladyslaw; Wolters, Helmut; Worm, Steven; Wosiek, Barbara; Wotschack, Jorg; Woudstra, Martin; Wozniak, Krzysztof; Wu, Mengqing; Wu, Miles; Wu, Sau Lan; Wu, Xin; Wu, Yusheng; Wyatt, Terry Richard; Wynne, Benjamin; Xella, Stefania; Xi, Zhaoxu; Xu, Da; Xu, Lailin; Yabsley, Bruce; Yacoob, Sahal; Yamaguchi, Daiki; Yamaguchi, Yohei; Yamamoto, Akira; Yamamoto, Shimpei; Yamanaka, Takashi; Yamauchi, Katsuya; Yamazaki, Yuji; Yan, Zhen; Yang, Haijun; Yang, Hongtao; Yang, Yi; Yang, Zongchang; Yao, Weiming; Yap, Yee Chinn; Yasu, Yoshiji; Yatsenko, Elena; Yau Wong, Kaven Henry; Ye, Jingbo; Ye, Shuwei; Yeletskikh, Ivan; Yildirim, Eda; Yorita, Kohei; Yoshida, Rikutaro; Yoshihara, Keisuke; Young, Charles; Young, Christopher John; Youssef, Saul; Yu, David Ren-Hwa; Yu, Jaehoon; Yu, Jiaming; Yu, Jie; Yuan, Li; Yuen, Stephanie P; Yusuff, Imran; Zabinski, Bartlomiej; Zacharis, Georgios; Zaidan, Remi; Zaitsev, Alexander; Zakharchuk, Nataliia; Zalieckas, Justas; Zaman, Aungshuman; Zambito, Stefano; Zanello, Lucia; Zanzi, Daniele; Zeitnitz, Christian; Zeman, Martin; Zemla, Andrzej; Zeng, Jian Cong; Zeng, Qi; Zenin, Oleg; Ženiš, Tibor; Zerwas, Dirk; Zhang, Dongliang; Zhang, Fangzhou; Zhang, Guangyi; Zhang, Huijun; Zhang, Jinlong; Zhang, Lei; Zhang, Liqing; Zhang, Matt; Zhang, Rui; Zhang, Ruiqi; Zhang, Xueyao; Zhang, Yu; Zhang, Zhiqing; Zhao, Xiandong; Zhao, Yongke; Zhao, Zhengguo; Zhemchugov, Alexey; Zhong, Jiahang; Zhou, Bing; Zhou, Chen; Zhou, Lei; Zhou, Li; Zhou, Maosen; Zhou, Mingliang; Zhou, Ning; Zhu, Cheng Guang; Zhu, Hongbo; Zhu, Junjie; Zhu, Yingchun; Zhuang, Xuai; Zhukov, Konstantin; Zibell, Andre; Zieminska, Daria; Zimine, Nikolai; Zimmermann, Christoph; Zimmermann, Stephanie; Zinonos, Zinonas; Zinser, Markus; Ziolkowski, Michael; Živković, Lidija; Zobernig, Georg; Zoccoli, Antonio; zur Nedden, Martin; Zwalinski, Lukasz

    2017-03-27

    This paper describes the algorithms for the reconstruction and identification of electrons in the central region of the ATLAS detector at the Large Hadron Collider (LHC). These algorithms were used for all ATLAS results with electrons in the final state that are based on the 2012 pp collision data produced by the LHC at $\\sqrt{\\mathrm{s}}$ = 8 TeV. The efficiency of these algorithms, together with the charge misidentification rate, is measured in data and evaluated in simulated samples using electrons from $Z\\rightarrow ee$, $Z\\rightarrow ee\\gamma$ and $J/\\psi \\rightarrow ee$ decays. For these efficiency measurements, the full recorded data set, corresponding to an integrated luminosity of 20.3 fb$^{-1}$, is used. Based on a new reconstruction algorithm used in 2012, the electron reconstruction efficiency is 97% for electrons with $E_\\mathrm{T}=15$ GeV and 99% at $E_\\mathrm{T} = 50$ GeV. Combining this with the efficiency of additional selection criteria to reject backgrounds from background electrons or misi...

  13. Pregnancy with Portal Hypertension

    Science.gov (United States)

    Aggarwal, Neelam; Negi, Neha; Aggarwal, Aakash; Bodh, Vijay; Dhiman, Radha K.

    2014-01-01

    Even though pregnancy is rare with cirrhosis and advanced liver disease, but it may co-exist in the setting of non-cirrhotic portal hypertension as liver function is preserved but whenever encountered together is a complex clinical dilemma. Pregnancy in a patient with portal hypertension presents a special challenge to the obstetrician as so-called physiological hemodynamic changes associated with pregnancy, needed for meeting demands of the growing fetus, worsen the portal hypertension thereby putting mother at risk of potentially life-threatening complications like variceal hemorrhage. Risks of variceal bleed and hepatic decompensation increase many fold during pregnancy. Optimal management revolves round managing the portal hypertension and its complications. Thus management of such cases requires multi-speciality approach involving obstetricians experienced in dealing with high risk cases, hepatologists, anesthetists and neonatologists. With advancement in medical field, pregnancy is not contra-indicated in these women, as was previously believed. This article focuses on the different aspects of pregnancy with portal hypertension with special emphasis on specific cause wise treatment options to decrease the variceal bleed and hepatic decompensation. Based on extensive review of literature, management from pre-conceptional period to postpartum is outlined in order to have optimal maternal and perinatal outcomes. PMID:25755552

  14. The NOAO NVO Portal

    Science.gov (United States)

    Miller, C. J.; Gasson, D.; Fuentes, E.

    2007-10-01

    The NOAO NVO Portal is a web application for one-stop discovery, analysis, and access to VO-compliant imaging data and services. The current release allows for GUI-based discovery of nearly a half million images from archives such as the NOAO Science Archive, the Hubble Space Telescope WFPC2 and ACS instruments, XMM-Newton, Chandra, and ESO's INT Wide-Field Survey, among others. The NOAO Portal allows users to view image metadata, footprint wire-frames, FITS image previews, and provides one-click access to science quality imaging data throughout the entire sky via the Firefox web browser (i.e., no applet or code to download). Users can stage images from multiple archives at the NOAO NVO Portal for quick and easy bulk downloads. The NOAO NVO Portal also provides simplified and direct access to VO analysis services, such as the WESIX catalog generation service. We highlight the features of the NOAO NVO Portal (http://nvo.noao.edu).

  15. Radioisotopic flow scanning for portal blood flow and portal hypertension

    International Nuclear Information System (INIS)

    Hesdorffer, C.S.; Bezwoda, W.R.; Danilewitz, M.D.; Esser, J.D.; Tobias, M.

    1987-01-01

    The use of a simple, noninvasive, isotope scanning technique for the determination of relative portal blood flow and detection of portal hypertension is described. Using this technique the presence of portal hypertension was demonstrated in seven of nine patients known to have elevated portal venous pressure. By contrast, esophageal varices were demonstrated in only five of these patients, illustrating the potential value of the method. Furthermore, this technique has been adapted to the study of portal blood flow in patients with myeloproliferative disorders with splenomegaly but without disturbances in hepatic architecture. Results demonstrate that the high relative splenic flow resulting from the presence of splenomegaly may in turn be associated with elevated relative portal blood flow and portal hypertension. The theoretic reasons for the development of flow-related portal hypertension and its relationship to splenic blood flow are discussed

  16. Impact of health portal enrollment with email reminders on adherence to clinic appointments: a pilot study.

    Science.gov (United States)

    Horvath, Monica; Levy, Janet; L'Engle, Pete; Carlson, Boyd; Ahmad, Asif; Ferranti, Jeffrey

    2011-05-26

    Internet portal technologies that provide access to portions of electronic health records have the potential to revolutionize patients' involvement in their care. However, relatively few descriptions of the demographic characteristics of portal enrollees or of the effects of portal technology on quality outcomes exist. This study examined data from patients who attended one of seven Duke Medicine clinics and who were offered the option of enrolling in and using the Duke Medicine HealthView portal (HVP). The HVP allows patients to manage details of their appointment scheduling and provides automated email appointment reminders in addition to the telephone and mail reminders that all patients receive. Our objective was to test whether portal enrollment with an email reminder functionality is significantly related to decreases in rates of appointment "no-shows," which are known to impair clinic operational efficiency. Appointment activity during a 1-year period was examined for all patients attending one of seven Duke Medicine clinics. Patients were categorized as portal enrollees or as nonusers either by their status at time of appointment or at the end of the 1-year period. Demographic characteristics and no-show rates among these groups were compared. A binomial logistic regression model was constructed to measure the adjusted impact of HVP enrollment on no-show rates, given confounding factors. To demonstrate the effect of HVP use over time, monthly no-show rates were calculated for patient appointment keeping and contrasted between preportal and postportal deployment periods. Across seven clinics, 58,942 patients, 15.7% (9239/58,942) of whom were portal enrollees, scheduled 198,199 appointments with an overall no-show rate of 9.9% (19,668/198,199). We found that HVP enrollees were significantly more likely to be female, white, and privately insured compared with nonusers. Bivariate no-show rate differences between portal enrollment groups varied widely according

  17. Probabilities and energies to obtain the counting efficiency of electron-capture nuclides, KLMN model

    International Nuclear Information System (INIS)

    Casas Galiano, G.; Grau Malonda, A.

    1994-01-01

    An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electron-capture in the counting efficiency when the atomic number of the nuclide is high

  18. Power efficiency optimization of disk-loaded waveguide traveling wave structure of electron linear accelerator

    International Nuclear Information System (INIS)

    Yang Jinghe; Li Jinhai; Li Chunguang

    2014-01-01

    Disk-loaded waveguide traveling wave structure (TWS), which is widely used in scientific research and industry, is a vital accelerating structure in electron linear accelerator. The power efficiency is an important parameter for designing TWS, which greatly effects the expenses for the fabrication and commercial running. The key parameters related with power efficiency were studied for TWS optimization. The result was proved by experiment result, and it shows some help for accelerator engineering. (authors)

  19. Personalization Methods for Internet Portals

    OpenAIRE

    Barbara Dębska; Agnieszka Kubacka

    2012-01-01

    The article presents methods of acquiring and gathering data about users of internet portals, with particular emphasis on educational portals. Definitions, aims and tasks related to the process of personalization of e-learning portals are thoroughly discussed. So are knowledge acquisition techniques applied in personalization, especially artificial intelligence methods.

  20. The Learning Portal

    Science.gov (United States)

    Staudt, Carolyn; Hanzlick-Burton, Camden; Williamson, Carol; McIntyre, Cynthia

    2015-01-01

    The Innovative Technology in Science Inquiry (ITSI) project is a learning portal with hundreds of free, customizable science, math, and engineering activities funded by the National Science Foundation at the Concord Consortium, a nonprofit research and development organization dedicated to transforming education through technology. The project…

  1. BRAZILIAN NEWS PORTALS CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Heloiza G. Herckovitz

    2011-02-01

    Full Text Available A content analysis of four Brazilian news media portals found that economic news dominated the top headlines with little attention paid to education, the environment and welfare. Other trends included a focus on local events and national news sources, reliance on few sources, mostly official ones, and a low percentage of news that fitted the concept of newsworthiness (a combination of both social significance and deviance concepts. Other findings of a study of 432 top news stories published by UOL, Estadão, iG and Terra during a 15-day period between February and March 2008 indicate that the top portions of the portals’ front pages carry news that lacks story depth, editorial branding, and multimedia applications. The results suggest that online news portals are in their infancy although Brazil has the largest online population of Latin America. This study hopes to shed light on the gatekeeping process in Brazilian news portals. Brazilian media portals have yet to become a significant editorial force able to provide knowledge about social issues and public affairs in a socially responsible fashione.

  2. Design and Implementation of a Portal for the Medical Equipment Market: MEDICOM

    Science.gov (United States)

    Kalivas, Dimitris; Panou-Diamandi, Ourania; Zeelenberg, Cees; van Nimwegen, Chris

    2001-01-01

    Background The MEDICOM (Medical Products Electronic Commerce) Portal provides the electronic means for medical-equipment manufacturers to communicate online with their customers while supporting the Purchasing Process and Post Market Surveillance. The Portal offers a powerful Internet-based search tool for finding medical products and manufacturers. Its main advantage is the fast, reliable and up-to-date retrieval of information while eliminating all unrelated content that a general-purpose search engine would retrieve. The Universal Medical Device Nomenclature System (UMDNS) registers all products. The Portal accepts end-user requests and generates a list of results containing text descriptions of devices, UMDNS attribute values, and links to manufacturer Web pages and online catalogues for access to more-detailed information. Device short descriptions are provided by the corresponding manufacturer. The Portal offers technical support for integration of the manufacturers' Web sites with itself. The network of the Portal and the connected manufacturers' sites is called the MEDICOM system. Objective To establish an environment hosting all the interactions of consumers (health care organizations and professionals) and providers (manufacturers, distributors, and resellers of medical devices). Methods The Portal provides the end-user interface, implements system management, and supports database compatibility. The Portal hosts information about the whole MEDICOM system (Common Database) and summarized descriptions of medical devices (Short Description Database); the manufacturers' servers present extended descriptions. The Portal provides end-user profiling and registration, an efficient product-searching mechanism, bulletin boards, links to on-line libraries and standards, on-line information for the MEDICOM system, and special messages or advertisements from manufacturers. Platform independence and interoperability characterize the system design. Relational Database

  3. Design and implementation of a portal for the medical equipment market: MEDICOM.

    Science.gov (United States)

    Palamas, S; Kalivas, D; Panou-Diamandi, O; Zeelenberg, C; van Nimwegen, C

    2001-01-01

    The MEDICOM (Medical Products Electronic Commerce) Portal provides the electronic means for medical-equipment manufacturers to communicate online with their customers while supporting the Purchasing Process and Post Market Surveillance. The Portal offers a powerful Internet-based search tool for finding medical products and manufacturers. Its main advantage is the fast, reliable and up-to-date retrieval of information while eliminating all unrelated content that a general-purpose search engine would retrieve. The Universal Medical Device Nomenclature System (UMDNS) registers all products. The Portal accepts end-user requests and generates a list of results containing text descriptions of devices, UMDNS attribute values, and links to manufacturer Web pages and online catalogues for access to more-detailed information. Device short descriptions are provided by the corresponding manufacturer. The Portal offers technical support for integration of the manufacturers Web sites with itself. The network of the Portal and the connected manufacturers sites is called the MEDICOM system. To establish an environment hosting all the interactions of consumers (health care organizations and professionals) and providers (manufacturers, distributors, and resellers of medical devices). The Portal provides the end-user interface, implements system management, and supports database compatibility. The Portal hosts information about the whole MEDICOM system (Common Database) and summarized descriptions of medical devices (Short Description Database); the manufacturers servers present extended descriptions. The Portal provides end-user profiling and registration, an efficient product-searching mechanism, bulletin boards, links to on-line libraries and standards, on-line information for the MEDICOM system, and special messages or advertisements from manufacturers. Platform independence and interoperability characterize the system design. Relational Database Management Systems are used for

  4. Defining Usability Heuristics for Adoption and Efficiency of an Electronic Workflow Document Management System

    Science.gov (United States)

    Fuentes, Steven

    2017-01-01

    Usability heuristics have been established for different uses and applications as general guidelines for user interfaces. These can affect the implementation of industry solutions and play a significant role regarding cost reduction and process efficiency. The area of electronic workflow document management (EWDM) solutions, also known as…

  5. Lowest order in inelastic tunneling approximation : efficient scheme for simulation of inelastic electron tunneling data

    NARCIS (Netherlands)

    Rossen, E.T.R.; Flipse, C.F.J.; Cerda, J.I.

    2013-01-01

    We have developed an efficient and accurate formalism which allows the simulation at the ab initio level of inelastic electron tunneling spectroscopy data under a scanning tunneling microscope setup. It exploits fully the tunneling regime by carrying out the structural optimization and vibrational

  6. Using Patient Portals to Increase Engagement in Patients with Cancer.

    Science.gov (United States)

    Rodriguez, Elizabeth S

    2018-04-03

    To review patient portals which serve as a tool for patient engagement by increasing access to electronic health care information and expanding ways to communicate with health care providers. Reviews of the literature and first-hand experience. Meaningful Use requirements propelled the design and development of patient portals in recent years. Patient engagement in oncology can improve quality of life and outcomes. Oncology nurses facilitate patient adoption of patient portals and support usage. Patient education helps manage communication expectations and understanding of online medical information. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Novel multi-chromophor light absorber concepts for DSSCs for efficient electron injection

    Energy Technology Data Exchange (ETDEWEB)

    Schuetz, Robert; Strothkaemper, Christian; Bartelt, Andreas; Hannappel, Thomas; Eichberger, Rainer [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Fasting, Carlo [Institut fuer Organische Chemie, Freie Universitaet Berlin, Takustrasse 3, 14195 Berlin (Germany); Thomas, Inara [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institut fuer Organische Chemie, Freie Universitaet Berlin, Takustrasse 3, 14195 Berlin (Germany)

    2011-07-01

    Dye sensitized solar cells (DSSCs) operate by injecting electrons from the excited state of a light-harvesting dye into the continuum of conduction band states of a wide bandgap semiconductor. The light harvesting efficiency of pure organic dyes is limited by a narrow spectral electronic transition. A beneficial broad ground state absorption in the VIS region can be achieved by applying a single molecular dye system with multiple chromophors involving a Foerster resonance energy transfer (FRET) mechanism for an efficient electron injection. A model donor acceptor dye system capable for FRET chemically linked to colloidal TiO{sub 2} and ZnO nanorod surfaces was investigated in UHV environment. We used VIS/NIR femtosecond transient absorption spectroscopy and optical pump terahertz probe spectroscopy to study the charge injection dynamics of the antenna system. Different chromophors attached to a novel scaffold/anchor system connecting the organic absorber unit to the metal oxide semiconductor were probed.

  8. A relativistic model of electron cyclotron current drive efficiency in tokamak plasmas

    Directory of Open Access Journals (Sweden)

    Lin-Liu Y.R.

    2012-09-01

    Full Text Available A fully relativistic model of electron cyclotron current drive (ECCD efficiency based on the adjoint function techniques is considered. Numerical calculations of the current drive efficiency in a tokamak by using the variational approach are performed. A fully relativistic extension of the variational principle with the modified basis functions for the Spitzer function with momentum conservation in the electron-electron collision is described in general tokamak geometry. The model developed has generalized that of Marushchenko’s (N.B . Marushchenko, et al. Fusion Sci. & Tech., 2009, which is extended for arbitrary temperatures and covers exactly the asymptotic for u ≫ 1 when Z → ∞, and suitable for ray-tracing calculations.

  9. On line portal imaging

    International Nuclear Information System (INIS)

    Munro, Peter

    1995-01-01

    Purpose/Objective: The purpose of this presentation is to review the physics of imaging with high energy x-ray beams; examine the various imaging devices that have been developed for portal imaging; describe some of the image registration methods that have been developed to determine errors in patient positioning quantitatively; and discuss some of the ways that portal imaging has been incorporated into routine clinical practice. Verification of patient positioning has always been an important aspect of external beam radiation therapy. Checks of patient positioning have generally been done with film, however, film suffers from a number of drawbacks, such as poor image display and delays due to film development. Over the past decade many portal imaging devices have been developed by individual investigators and most accelerator manufacturers now offer 'on-line' portal imaging systems, which are intended to overcome the limitations of portal films. The commercial devices can be classified into three categories: T.V. camera-based systems, liquid ionisation chamber systems, and amorphous silicon systems. Many factors influence the quality of images generated by these portal imaging systems. These include factors which are unavoidable (e.g., low subject contrast), factors which depend upon the individual imaging device forming the image (e.g., dose utilisation, spatial resolution) as well as factors which depend upon the characteristics of the linear accelerator irradiating the imaging system (x-ray source size, image magnification). The fundamental factors which limit image quality and the characteristics of individual imaging systems, such as spatial resolution, temporal response, and quantum utilisation will be discussed. One of the major advantages of on-line portal imaging is that many quantitative techniques have been developed to detect errors in patient positioning. The general approach is to register anatomic structures on a portal image with the same

  10. An Efficient Electronic English Auction System with a Secure On-Shelf Mechanism and Privacy Preserving

    Directory of Open Access Journals (Sweden)

    Hong Zhong

    2016-01-01

    Full Text Available With the rapid development of the Internet, electronic commerce has become more and more popular. As an important element of e-commerce, many Internet companies such as Yahoo! and eBay have launched electronic auction systems. However, like most electronic commerce products, safety is an important issue that should be addressed. Many researchers have proposed secure electronic auction mechanisms, but we found that some of them do not exhibit the property of unlinkability, which leads to the leakage of users’ privacy. Considering the importance of privacy preservation, we have designed a new auction mechanism. Through symmetrical key establishment in the registration phase, all messages transmitted over the Internet would be protected and, meanwhile, achieve the property of unlinkability. The security analysis and performance analysis show that our protocol fulfills more security properties and is more efficient for implementation compared with recent works.

  11. Angiography in portal hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Zeitler, E

    1982-04-05

    We report on the cooperative possibilities the radiologist has as to diagnosis and therapy of portal hypertension. The catheter angiography allows to make a differentiation between pre- and intrahepatic bloc and the localization of bleeding esophagus varices. Only after all endoscopic measures with sclerotherapy and Laser coagulation have failed, catheter angiography will be carried out as a therapeutic measure. The future development, however, will give the opportunity to a series of therapeutic attempts on the field of interventional radiology.

  12. Angiography in portal hypertension

    International Nuclear Information System (INIS)

    Zeitler, E.

    1982-01-01

    We report on the cooperative possibilities the radiologist has as to diagnosis and therapy of portal hypertension. The catheter angiography allows to make a differentiation between pre- and intrahepatic bloc and the localization of bleeding esophagus varices. Only after all endoscopic measures with sclerotherapy and Laser coagulation have failed, catheter angiography will be carried out as a therapeutic measure. The future development, however, will give the opportunity to a series of therapeutic attempts on the field of interventional radiology. (orig.) [de

  13. Detection efficiency for radionuclides decaying by electron capture and gamma-Ray

    International Nuclear Information System (INIS)

    Grau, A.; Fernandez, A.

    1985-01-01

    In this paper, the electron capture partial counting efficiency vs the figure of merit for electron-capture and gamma-ray emitters has been computed. The radionuclides tabulated are 48 c r, 54 M n, 57 C o 56 N i, 72 S e, 73 A s, 85 S r, 88 Z r, 92 N b, 103 P d, 111 l n, 119 S b, 125 I , 139 C e and 152 D y. It has been assumed that the liquid is a toluene based scintillator solution in standard glass vials containing 15 cm 3 . (Author) 17 refs

  14. Portal Annular Pancreas

    Science.gov (United States)

    Harnoss, Jonathan M.; Harnoss, Julian C.; Diener, Markus K.; Contin, Pietro; Ulrich, Alexis B.; Büchler, Markus W.; Schmitz-Winnenthal, Friedrich H.

    2014-01-01

    Abstract Portal annular pancreas (PAP) is an asymptomatic congenital pancreas anomaly, in which portal and/or mesenteric veins are encased by pancreas tissue. The aim of the study was to determine the role of PAP in pancreatic surgery as well as its management and potential complication, specifically, postoperative pancreatic fistula (POPF). On the basis of a case report, the MEDLINE and ISI Web of Science databases were systematically reviewed up to September 2012. All articles describing a case of PAP were considered. In summary, 21 studies with 59 cases were included. The overall prevalence of PAP was 2.4% and the patients' mean (SD) age was 55.9 (16.2) years. The POPF rate in patients with PAP (12 pancreaticoduodenectomies and 3 distal pancreatectomies) was 46.7% (in accordance with the definition of the International Study Group of Pancreatic Surgery). Portal annular pancreas is a quite unattended pancreatic variant with high prevalence and therefore still remains a clinical challenge to avoid postoperative complications. To decrease the risk for POPF, attentive preoperative diagnostics should also focus on PAP. In pancreaticoduodenectomy, a shift of the resection plane to the pancreas tail should be considered; in extensive pancreatectomy, coverage of the pancreatic remnant by the falciform ligament could be a treatment option. PMID:25207658

  15. Obliterative portal venopathy without portal hypertension: an underestimated condition.

    Science.gov (United States)

    Guido, Maria; Sarcognato, Samantha; Sonzogni, Aurelio; Lucà, Maria Grazia; Senzolo, Marco; Fagiuoli, Stefano; Ferrarese, Alberto; Pizzi, Marco; Giacomelli, Luciano; Colloredo, Guido

    2016-03-01

    Obliterative portal venopathy without portal hypertension has been described by a single study in a limited number of patients, thus very little is known about this clinical condition. This study aimed to investigate the prevalence of obliterative portal venopathy and its clinical-pathological correlations in patients with cryptogenic chronic liver test abnormalities without clinical signs of portal hypertension. We analysed 482 liver biopsies from adults with non-cirrhotic cryptogenic chronic liver disorders and without any clinical signs of portal hypertension, consecutively enrolled in a 5-year period. Twenty cases of idiopathic non-cirrhotic portal hypertension diagnosed in the same period, were included for comparison. Histological findings were matched with clinical and laboratory features. Obliterative portal venopathy was identified in 94 (19.5%) of 482 subjects and in all 20 cases of idiopathic non-cirrhotic portal hypertension: both groups shared the entire spectrum of histological changes described in the latter condition. The prevalence of incomplete fibrous septa and nodular regenerative hyperplasia was higher in the biopsies of idiopathic non-cirrhotic portal hypertension (P = 0.006 and P = 0.002), a possible hint of a more advanced stage of the disease. The two groups also shared several clinical laboratory features, including a similar liver function test profile, concomitant prothrombotic conditions and extrahepatic autoimmune disorders. Obliterative portal venopathy occurs in a substantial proportion of patients with unexplained chronic abnormal liver function tests without portal hypertension. The clinical-pathological profile of these subjects suggests that they may be in an early (non-symptomatic) stage of idiopathic non-cirrhotic portal hypertension. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Development of a computerized portal verification scheme for pelvic treatment fields

    International Nuclear Information System (INIS)

    Nie, K.; Yin, F.-F.; Gao, Q.; Brasacchio, R.

    1996-01-01

    Purpose/Objective: At present, treatment verification between portal and reference images is performed based on manually-identified features by radiation oncologist, which is both time-consuming and potentially error-prone. There is a demand for the computerized verification procedure in clinical application. The purpose of this study is to develop a computerized portal verification scheme for pelvic treatment fields. Materials/Methods: The automated verification system involves image acquisition, image feature extraction, feature matching between reference and portal images and quantitative evaluation of patient setup. Electronic portal images with a matrix size of 256 x 256 and 12 bit gray levels were acquired using a liquid matrix electronic portal imaging device. Simulation images were acquired by digitizing simulation films using a TV camera into images with 256 x 256 matrix and 8 bit gray levels. Initially a Canny edge detector is applied to identify the field edges and an elliptic Fourier transformation is used to correlate the size and shape information between the reference and portal field edges. Several measures can be calculated using the transformation coefficients to describe the field shape, size and orientation. The quantitative information regarding to the relative shifts, rotation and magnification factor between portal and reference field edges can then be determined based on these measures. Next the pelvic brim, which is typically used as the landmark for radiation treatment verification, is identified by a pyramid searching process with double snakes defined from initial global area to final local area. A snake is an active model and energy-minimizing spline guided by external constraint forces and influenced by image forces that pull it toward features such as lines and edges. The search range is limited to the region between two snakes. Sobel edge detector and wavelet transformation approach are used to generate a serial image forces at

  17. Diffraction efficiency of plasmonic gratings fabricated by electron beam lithography using a silver halide film

    Energy Technology Data Exchange (ETDEWEB)

    Sudheer,, E-mail: sudheer@rrcat.gov.in, E-mail: sudheer.rrcat@gmail.com; Tiwari, P.; Srivastava, Himanshu; Rai, V. N.; Srivastava, A. K.; Naik, P. A. [Homi Bhabha National Institute, Mumbai, Maharashtra 400094 (India); Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Porwal, S. [Solid State Lasers Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Bhartiya, S. [Homi Bhabha National Institute, Mumbai, Maharashtra 400094 (India); Laser Materials Development and Device Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Rao, B. T. [Homi Bhabha National Institute, Mumbai, Maharashtra 400094 (India); Laser Materials Processing Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India); Sharma, T. K. [Homi Bhabha National Institute, Mumbai, Maharashtra 400094 (India); Solid State Lasers Division, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh 452013 (India)

    2016-07-28

    The silver nanoparticle surface relief gratings of ∼10 μm period are fabricated using electron beam lithography on the silver halide film substrate. Morphological characterization of the gratings shows that the period, the shape, and the relief depth in the gratings are mainly dependent on the number of lines per frame, the spot size, and the accelerating voltage of electron beam raster in the SEM. Optical absorption of the silver nanoparticle gratings provides a broad localized surface plasmon resonance peak in the visible region, whereas the intensity of the peaks depends on the number density of silver nanoparticles in the gratings. The maximum efficiency of ∼7.2% for first order diffraction is observed for the grating fabricated at 15 keV. The efficiency is peaking at 560 nm with ∼380 nm bandwidth. The measured profiles of the diffraction efficiency for the gratings are found in close agreement with the Raman-Nath diffraction theory. This technique provides a simple and efficient method for the fabrication of plasmonic nanoparticle grating structures with high diffraction efficiency having broad wavelength tuning.

  18. Portal hemodynamics in chronic portal-systemic encephalopathy

    International Nuclear Information System (INIS)

    Takashi, Motohide; Igarashi, Masahiko; Hino, Shinichi; Takayasu, Kenichi; Goto, Nobuaki; Musha, Hirotaka; Ohnishi, Kunihiko; Okuda, Kunio

    1985-01-01

    A portal hemodynamic study was made in 7 consecutive patients with chronic portal-systemic encephalopathy by percutaneous transhepatic catheterization of the portal vein and injecting contrast medium into the superior mesenteric vein or by superior mesenteric arterial portography in comparison with patients without encephalopathy studied by percutaneous catheterization of these veins. It is suggested that chronic portal-systemic encephalopathy is a result of a large collateral route shunting a large proportion of the superior mesenteric venous blood into systemic circulation, and that development of such collaterals precludes formation of large esophageal varices. (Auth.)

  19. Efficient scattering of electrons below few keV by Time Domain Structures around injection fronts

    Science.gov (United States)

    Vasko, I.; Agapitov, O. V.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.

    2016-12-01

    Van Allen Probes observations show an abundance of non-linear large-amplitude electrostatic spikes around injection fronts in the outer radiation belt. These spikes referred to as Time Domain Structures (TDS) include electron holes, double layers and more complicated solitary waves. The electron scattering driven by TDS may not be evaluated via the standard quasi-linear theory, since TDS are in principle non-linear plasma modes. In this paper we analyze the scattering of electrons by three-dimensional TDS (with non-negligible perpendicular electric field) around injection fronts. We derive the analytical formulas describing the local scattering by single TDS and show that the most efficiently scattered electrons are those in the first cyclotron resonance (electrons crossing TDS on a time scale comparable with their gyroperiod). The analytical formulas are verified via the test-particle simulation. We compute the bounce-averaged diffusion coefficients and demonstrate their dependence on the TDS spatial distribution, individual TDS parameters and L shell. We show that TDS are able to provide the pitch-angle scattering of <5 keV electrons at rate 10-2-10-4 s-1 and, thus, can be responsible for driving loss of electrons out of injections fronts on a time scale from few minutes to few hours. TDS can be, thus, responsible for driving diffuse aurora precipitations conjugated to injection fronts. We show that the pitch-angle scattering rates driven by TDS are comparable with those due to chorus waves and exceed those due to electron cyclotron harmonics. For injections fronts with no significant wave activity in the frequency range corresponding to chorus waves, TDS can be even dominant mechanism for losses of below few keV electrons.

  20. The accuracy and efficiency of electronic screening for recruitment into a clinical trial on COPD.

    Science.gov (United States)

    Schmickl, Christopher N; Li, Man; Li, Guangxi; Wetzstein, Marnie M; Herasevich, Vitaly; Gajic, Ognjen; Benzo, Roberto P

    2011-10-01

    Participant recruitment is an important process in successful conduct of randomized controlled trials. To facilitate enrollment into a National Institutes of Health-sponsored clinical trial involving patients with chronic obstructive pulmonary disease (COPD), we developed and prospectively validated an automated electronic screening tool based on boolean free-text search of admission notes in electronic medical records. During a 2-week validation period, all patients admitted to prespecified general medical services were screened for eligibility by both the electronic screening tool and a COPD nurse. Group discussion was the gold standard for confirmation of true-positive results. Compared with the gold standard, electronic screening yielded 100% sensitivity, 92% specificity, 100% negative predictive value, and 72% positive predictive value. Compared with traditional manual screening, electronic screening demonstrated time-saving potential of 76%. Thus, the electronic screening tool accurately identifies potential study subjects and improves efficiency of patient accrual for a clinical trial on COPD. This method may be expanded into other institutional and clinical settings. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. PSUP: A Planetary SUrface Portal

    Science.gov (United States)

    Poulet, F.; Quantin-Nataf, C.; Ballans, H.; Dassas, K.; Audouard, J.; Carter, J.; Gondet, B.; Lozac'h, L.; Malapert, J.-C.; Marmo, C.; Riu, L.; Séjourné, A.

    2018-01-01

    The large size and complexity of planetary data acquired by spacecraft during the last two decades create a demand within the planetary community for access to the archives of raw and high level data and for the tools necessary to analyze these data. Among the different targets of the Solar System, Mars is unique as the combined datasets from the Viking, Mars Global Surveyor, Mars Odyssey, Mars Express and Mars Reconnaissance Orbiter missions provide a tremendous wealth of information that can be used to study the surface of Mars. The number and the size of the datasets require an information system to process, manage and distribute data. The Observatories of Paris Sud (OSUPS) and Lyon (OSUL) have developed a portal, called PSUP (Planetary SUrface Portal), for providing users with efficient and easy access to data products dedicated to the Martian surface. The objectives of the portal are: 1) to allow processing and downloading of data via a specific application called MarsSI (Martian surface data processing Information System); 2) to provide the visualization and merging of high level (image, spectral, and topographic) products and catalogs via a web-based user interface (MarsVisu), and 3) to distribute some of these specific high level data with an emphasis on products issued by the science teams of OSUPS and OSUL. As the MarsSI service is extensively described in a companion paper (Quantin-Nataf et al., companion paper, submitted to this special issue), the present paper focus on the general architecture and the functionalities of the web-based user interface MarsVisu. This service provides access to many data products for Mars: albedo, mineral and thermal inertia global maps from spectrometers; mosaics from imagers; image footprints and rasters from the MarsSI tool; high level specific products (defined as catalogs or vectors). MarsVisu can be used to quickly assess the visualized processed data and maps as well as identify areas that have not been mapped yet

  2. Knowledge Portals: Ontologies at Work

    OpenAIRE

    Staab, Steffen; Maedche, Alexander

    2001-01-01

    Knowledge portals provide views onto domain-specific information on the World Wide Web, thus helping their users find relevant, domain-specific information. The construction of intelligent access and the contribution of information to knowledge portals, however, remained an ad hoc task, requiring extensive manual editing and maintenance by the knowledge portal providers. To diminish these efforts, we use ontologies as a conceptual backbone for providing, accessing, and structuring information...

  3. Ferrocene-Functionalized Graphene Oxide Nanosheets: Efficient Electronic Communication between Ferrocene Centers across Graphene Nanosheets

    International Nuclear Information System (INIS)

    Lu, Yizhong; Jiang, Yuanyuan; Wu, Haibin; Chen, Wei

    2015-01-01

    Highlights: • Graphene oxide (GO) nanosheets functionalized with ferrocenyl moieties (GO-Fc) are fabricated. • GO-Fc shows efficient electronic communication between ferrocene centers. • GO-Fc exhibits two pairs of voltammetric peaks with a large potential spacing of 0.515 V. • GO-Fc shows a broad absorption peak in the near-infrared range (∼ 1428 nm) at mixed valence. - Abstract: Graphene oxide (GO) nanosheets functionalized with ferrocenyl moieties (GO-Fc) were fabricated through strong covalent C−C bonds. The resulting hybrid showed efficient electronic communication between ferrocene centers due to the strong electron delocalization facilitated by the large pi-pi conjugated structure of graphene sheets. The obtained hybrid exhibited two pairs of voltammetric peaks with a large potential spacing of 0.515 V and a broad absorption peak in the near-infrared range (∼ 1428 nm) at mixed valence. The electrochemical and near IR spectroscopic features suggested a Class II/III behavior of the intervalence charge transfer. This work indicates clearly that strong electronic coupling between ferrocene centers can be easily realized across graphene nanosheets with sp 2 -hybridized carbon

  4. Duplex sonography in portal hypertension

    International Nuclear Information System (INIS)

    Kwon, Hyuk Po; Jang, J. C.; Park, B. H.

    1990-01-01

    We measure the diameter and blood velocity of the portal vein in 50 patients with cirrhosis of the liver and 40 healthy subjects, and calculated cross sectional area, mean blood flow velocity, blood flow volume and congestion index. In patients with cirrhosis of the liver, the cross sectional area of the portal vein was significantly increased: the mean blood flow volume was significantly reduced; the blood flow volume was significantly increased; the congestion index of the portal vein was significantly increased. Duples sonography may play an important role in the diagnosis of portal hypertension

  5. The Seed Proteome Web Portal

    Directory of Open Access Journals (Sweden)

    Marc eGalland

    2012-06-01

    Full Text Available The Seed Proteome Web Portal (SPWP; http://www.seedproteome.com/ gives access to information both on quantitative seed proteomic data and on seed-related protocols. Firstly, the SPWP provides access to the 475 different Arabidopsis seed proteins annotated from 2 dimensional electrophoresis (2DE maps. Quantitative data are available for each protein according to their accumulation profile during the germination process. These proteins can be retrieved either in list format or directly on scanned 2DE maps. These proteomic data reveal that 40% of seed proteins maintain a stable abundance over germination, up to radicle protrusion. During sensu stricto germination (24 h upon imbibition about 50% of the proteins display quantitative variations, exhibiting an increased abundance (35% or a decreasing abundance (15%. Moreover, during radicle protrusion (24 h to 48 h upon imbibition, 41% proteins display quantitative variations with an increased (23% or a decreasing abundance (18%. In addition, an analysis of the seed proteome revealed the importance of protein post-translational modifications as demonstrated by the poor correlation (r2 = 0.29 between the theoretical (predicted from Arabidopsis genome and the observed protein isoelectric points. Secondly, the SPWP is a relevant technical resource for protocols specifically dedicated to Arabidopsis seed proteome studies. Concerning 2D electrophoresis, the user can find efficient procedures for sample preparation, electrophoresis coupled with gel analysis and protein identification by mass spectrometry, which we have routinely used during the last 12 years. Particular applications such as the detection of oxidized proteins or de novo synthetized proteins radiolabeled by [35S]-methionine are also given in great details. Future developments of this portal will include proteomic data from studies such as dormancy release and protein turnover through de novo protein synthesis analyses during germination.

  6. Efficient Regular Perovskite Solar Cells Based on Pristine [70]Fullerene as Electron-Selective Contact.

    Science.gov (United States)

    Collavini, Silvia; Kosta, Ivet; Völker, Sebastian F; Cabanero, German; Grande, Hans J; Tena-Zaera, Ramón; Delgado, Juan Luis

    2016-06-08

    [70]Fullerene is presented as an efficient alternative electron-selective contact (ESC) for regular-architecture perovskite solar cells (PSCs). A smart and simple, well-described solution processing protocol for the preparation of [70]- and [60]fullerene-based solar cells, namely the fullerene saturation approach (FSA), allowed us to obtain similar power conversion efficiencies for both fullerene materials (i.e., 10.4 and 11.4 % for [70]- and [60]fullerene-based devices, respectively). Importantly, despite the low electron mobility and significant visible-light absorption of [70]fullerene, the presented protocol allows the employment of [70]fullerene as an efficient ESC. The [70]fullerene film thickness and its solubility in the perovskite processing solutions are crucial parameters, which can be controlled by the use of this simple solution processing protocol. The damage to the [70]fullerene film through dissolution during the perovskite deposition is avoided through the saturation of the perovskite processing solution with [70]fullerene. Additionally, this fullerene-saturation strategy improves the performance of the perovskite film significantly and enhances the power conversion efficiency of solar cells based on different ESCs (i.e., [60]fullerene, [70]fullerene, and TiO2 ). Therefore, this universal solution processing protocol widens the opportunities for the further development of PSCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. A Strategy to Enhance the Efficiency of Quantum Dot-Sensitized Solar Cells by Decreasing Electron Recombination with Polyoxometalate/TiO2 as the Electronic Interface Layer.

    Science.gov (United States)

    Chen, Li; Chen, Weilin; Li, Jianping; Wang, Jiabo; Wang, Enbo

    2017-07-21

    Electron recombination occurring at the TiO 2 /quantum dot sensitizer/electrolyte interface is the key reason for hindering further efficiency improvements to quantum dot sensitized solar cells (QDSCs). Polyoxometalate (POM) can act as an electron-transfer medium to decrease electron recombination in a photoelectric device owing to its excellent oxidation/reduction properties and thermostability. A POM/TiO 2 electronic interface layer prepared by a simple layer-by-layer self-assembly method was added between fluorine-doped tin oxide (FTO) and mesoporous TiO 2 in the photoanode of QDSCs, and the effect on the photovoltaic performance was systematically investigated. Photovoltaic experimental results and the electron transmission mechanism show that the POM/TiO 2 electronic interface layer in the QDSCs can clearly suppress electron recombination, increase the electron lifetime, and result in smoother electron transmission. In summary, the best conversion efficiency of QDSCs with POM/TiO 2 electronic interface layers increases to 8.02 %, which is an improvement of 25.1 % compared with QDSCs without POM/TiO 2 . This work first builds an electron-transfer bridge between FTO and the quantum dot sensitizer and paves the way for further improved efficiency of QDSCs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. The Protein Model Portal.

    Science.gov (United States)

    Arnold, Konstantin; Kiefer, Florian; Kopp, Jürgen; Battey, James N D; Podvinec, Michael; Westbrook, John D; Berman, Helen M; Bordoli, Lorenza; Schwede, Torsten

    2009-03-01

    Structural Genomics has been successful in determining the structures of many unique proteins in a high throughput manner. Still, the number of known protein sequences is much larger than the number of experimentally solved protein structures. Homology (or comparative) modeling methods make use of experimental protein structures to build models for evolutionary related proteins. Thereby, experimental structure determination efforts and homology modeling complement each other in the exploration of the protein structure space. One of the challenges in using model information effectively has been to access all models available for a specific protein in heterogeneous formats at different sites using various incompatible accession code systems. Often, structure models for hundreds of proteins can be derived from a given experimentally determined structure, using a variety of established methods. This has been done by all of the PSI centers, and by various independent modeling groups. The goal of the Protein Model Portal (PMP) is to provide a single portal which gives access to the various models that can be leveraged from PSI targets and other experimental protein structures. A single interface allows all existing pre-computed models across these various sites to be queried simultaneously, and provides links to interactive services for template selection, target-template alignment, model building, and quality assessment. The current release of the portal consists of 7.6 million model structures provided by different partner resources (CSMP, JCSG, MCSG, NESG, NYSGXRC, JCMM, ModBase, SWISS-MODEL Repository). The PMP is available at http://www.proteinmodelportal.org and from the PSI Structural Genomics Knowledgebase.

  9. Probing the Highly Efficient Electron Transfer Dynamics between Zinc Protoporphyrin IX and Sodium Titanate Nanosheets.

    Science.gov (United States)

    Biswas, Sudipta; Mukherjee, Debdyuti; De, Swati; Kathiravan, Arunkumar

    2016-09-15

    Sodium titanate nanosheets (NaTiO2 NS) have been prepared by a new method and completely characterized by TEM, SEM, XRD, EDX, and XPS techniques. The sensitization of nanosheets is carried out with Zn protoporphyrin IX (ZnPPIX). The emission intensity of ZnPPIX is quenched by NaTiO2 NS, and the dominant process for this quenching has been attributed to the process of photoinduced electron injection from excited ZnPPIX to the nanosheets. Time resolved fluorescence measurement was used to elucidate the process of electron injection from the singlet state of ZnPPIX to the conduction band of NaTiO2 NS. Electron injection from the dye to the semiconductor is very fast (ket ≈ 10(11) s(-1)), much faster than previously reported rates. The large two-dimensional surface offered by the NaTiO2 NS for interaction with the dye and the favorable driving force for electron injection from ZnPPIX to NaTiO2 NS (ΔGinj = -0.66 V) are the two important factors responsible for such efficient electron injection. Thus, NaTiO2 NS can serve as an effective alternative to the use of TiO2 nanoparticles in dye sensitized solar cells (DSSCs).

  10. CT portal venography manifestations of portal collateral circulation in patients with portal hypertension due to cirrhosis

    International Nuclear Information System (INIS)

    Ni Ming; Lv Weifu; Deng Kexue

    2009-01-01

    Objective: To analyze CT portal venography (CTPV) manifestations of portal collateral circulation in patients with cirrhosis by using a 16-detector row spiral CT scanner. Methods: CTPV was performed in 36 patients with portal hypertension due to cirrhosis, the diagnosis was proved by clinical data, hepatic function findings and imaging signs. By using post-processing reconstruction technique, 3D images of portal venous system and portal collateral circulation were obtained. Results: CTPV images displayed the portal venous system and its collateral circulation stereoscopically. Of 36 patients, left gastric varices were seen in 29(80.6%), lower esophageal varices in 18(50.0%), short gastric or posterior gastric varices in 15(41.7%), paraesophageal varices in 9(25.0%), gastro-renal or splenorenal shunts in 8(22.2%), spongelike transformation of portal vein in 7(19.4%), paraumbilical and abdominal wall varices in 6(16.7%), congenital cavernous in 6(16.7%) and paravertebral venous shunts in 4(11.1%). Conclusion: CTPV can well display the site, extent and severity of the portal collateral circulation in patients with portal hypertension due to cirrhosis,which is of great clinical importance for judging the patient's condition, for selecting therapeutic protocols and for estimating prognosis. (authors)

  11. CAN MARKETING SUPPORT THE IMPLEMENTATION OF EFFECTIVE EGOVERNMENT? ANALYSIS OF THE SINGLE POINT OF ACCESS PORTAL FOR ROMANIAN ELECTRONIC PUBLIC SERVICES

    OpenAIRE

    Velicu Bogdan Calin

    2011-01-01

    The advances in technology hold great potential for helping Romanian government respond to its challenges namely, better service delivery, better procurement, efficient working and better communication with citizens and businesses. While the European Commission develops the main strategies on eGovernment, every member state has the freedom to identify its own necessities and decide according to specific social, administrative and economic context. Designing, cost setting, choosing the best su...

  12. Non-linear effects and thermoelectric efficiency of quantum dot-based single-electron transistors.

    Science.gov (United States)

    Talbo, Vincent; Saint-Martin, Jérôme; Retailleau, Sylvie; Dollfus, Philippe

    2017-11-01

    By means of advanced numerical simulation, the thermoelectric properties of a Si-quantum dot-based single-electron transistor operating in sequential tunneling regime are investigated in terms of figure of merit, efficiency and power. By taking into account the phonon-induced collisional broadening of energy levels in the quantum dot, both heat and electrical currents are computed in a voltage range beyond the linear response. Using our homemade code consisting in a 3D Poisson-Schrödinger solver and the resolution of the Master equation, the Seebeck coefficient at low bias voltage appears to be material independent and nearly independent on the level broadening, which makes this device promising for metrology applications as a nanoscale standard of Seebeck coefficient. Besides, at higher voltage bias, the non-linear characteristics of the heat current are shown to be related to the multi-level effects. Finally, when considering only the electronic contribution to the thermal conductance, the single-electron transistor operating in generator regime is shown to exhibit very good efficiency at maximum power.

  13. Beam energy distribution influences on density modulation efficiency in seeded free-electron lasers

    Directory of Open Access Journals (Sweden)

    Guanglei Wang

    2015-06-01

    Full Text Available The beam energy spread at the entrance of an undulator system is of paramount importance for efficient density modulation in high-gain seeded free-electron lasers (FELs. In this paper, the dependences of high harmonic bunching efficiency in high-gain harmonic generation (HGHG, echo-enabled harmonic generation (EEHG and phase-merging enhanced harmonic generation (PEHG schemes on the electron beam energy spread distribution are studied. Theoretical investigations and multidimensional numerical simulations are applied to the cases of uniform and saddle beam energy distributions and compared to a traditional Gaussian distribution. It shows that the uniform and saddle electron energy distributions significantly enhance the bunching performance of HGHG FELs, while they almost have no influence on EEHG and PEHG schemes. A further start-to-end simulation example demonstrated that, with the saddle distribution of sliced beam energy spread controlled by a laser heater, the 30th harmonic can be directly generated by a single-stage HGHG scheme for a soft x-ray FEL facility.

  14. Implementation of IMRT and VMAT using Delta4 phantom and portal dosimetry as dosimetry verification tools

    Energy Technology Data Exchange (ETDEWEB)

    Daci, Lulzime, E-mail: lulzime.daci@nodlandssykehuset.no [Nordland Hospital Trust, Bodø (Norway); Malkaj, Partizan, E-mail: malkaj-p@hotmail.com [Faculty of Mathematics Engineering and Physics Engineering, Polytechnic University of Tirana (Albania)

    2016-03-25

    In this study we analyzed and compared the dose distribution of different IMRT and VMAT plans with the intent to provide pre-treatment quality assurance using two different tools. Materials/Methods: We have used the electronic portal imaging device EPID after calibration to dose and correction for the background offset signal and also the Delta4 phantom after en evaluation of angular sensitivity. The Delta4 phantom has a two-dimensional array with ionization chambers. We analyzed three plans for each anatomical site calculated by Eclipse treatment planning system. The measurements were analyzed using γ-evaluation method with passing criteria 3% absolute dose and 3 mm distance to agreement (DTA). For all the plans the range of score has been from 97% to 99% for gantry fixed at 0° while for rotational planes there was a slightly decreased pass rates and above 95%. Point measurement with a ionization chamber were done in additional to see the accuracy of portal dosimetry and to evaluate the Delta4 device to various dose rates. Conclusions: Both Delt4 and Portal dosimetry shows good results between the measured and calculated doses. While Delta4 is more accurate in measurements EPID is more time efficient. We have decided to use both methods in the first steps of IMRT and VMAT implementation and later on to decide which of the tools to use depending on the complexity of plans, how much accurate we want to be and the time we have on the machine.

  15. Implementation of IMRT and VMAT using Delta4 phantom and portal dosimetry as dosimetry verification tools

    International Nuclear Information System (INIS)

    Daci, Lulzime; Malkaj, Partizan

    2016-01-01

    In this study we analyzed and compared the dose distribution of different IMRT and VMAT plans with the intent to provide pre-treatment quality assurance using two different tools. Materials/Methods: We have used the electronic portal imaging device EPID after calibration to dose and correction for the background offset signal and also the Delta4 phantom after en evaluation of angular sensitivity. The Delta4 phantom has a two-dimensional array with ionization chambers. We analyzed three plans for each anatomical site calculated by Eclipse treatment planning system. The measurements were analyzed using γ-evaluation method with passing criteria 3% absolute dose and 3 mm distance to agreement (DTA). For all the plans the range of score has been from 97% to 99% for gantry fixed at 0° while for rotational planes there was a slightly decreased pass rates and above 95%. Point measurement with a ionization chamber were done in additional to see the accuracy of portal dosimetry and to evaluate the Delta4 device to various dose rates. Conclusions: Both Delt4 and Portal dosimetry shows good results between the measured and calculated doses. While Delta4 is more accurate in measurements EPID is more time efficient. We have decided to use both methods in the first steps of IMRT and VMAT implementation and later on to decide which of the tools to use depending on the complexity of plans, how much accurate we want to be and the time we have on the machine.

  16. Lunar and Vesta Web Portals

    Science.gov (United States)

    Law, E.; JPL Luna Mapping; Modeling Project Team

    2015-06-01

    The Lunar Mapping and Modeling Project offers Lunar Mapping and Modeling Portal (http://lmmp.nasa.gov) and Vesta Trek Portal (http://vestatrek.jpl.nasa.gov) providing interactive visualization and analysis tools to enable users to access mapped Lunar and Vesta data products.

  17. WLCG Operations portal demo tutorial

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    This is a navigation through http://wlcg-ops.web.cern.ch/ the Worldwide LHC Computing Grid (WLCG) Operations' portal. In this portal you will find documentation and information about WLCG Operation activities for: System Administrators at the WLCG sites LHC Experiments Operation coordination people, including Task Forces and Working Groups

  18. Portal monitoring technology control process

    International Nuclear Information System (INIS)

    York, R.L.

    1998-01-01

    Portal monitors are an important part of the material protection, control, and accounting (MPC and A) programs in Russia and the US. Although portal monitors are only a part of an integrated MPC and A system, they are an effective means of controlling the unauthorized movement of special nuclear material (SNM). Russian technical experts have gained experience in the use of SNM portal monitors from US experts ad this has allowed them to use the monitors more effectively. Several Russian institutes and companies are designing and manufacturing SNM portal monitors in Russia. Interactions between Russian and US experts have resulted in improvements to the instruments. SNM portal monitor technology has been effectively transferred from the US to Russia and should be a permanent part of the Russian MPC and A Program. Progress in the implementation of the monitors and improvements to how they are used are discussed

  19. Multi-controller based 29 channel whole body portal monitor

    International Nuclear Information System (INIS)

    Dheeraj Reddy, J.; Narender Reddy, J.

    2004-01-01

    Portal Monitors are an essential part of personnel monitoring programme in any Nuclear Power Plant or Radiochemical/Reprocessing Plant. Compared to conventional Portal Monitors, whole-body Portals are preferred, for effective monitoring of entire body of the person being monitored for radioactive contamination. This is achieved by effectively distributing a large number of detectors on front/back of the person being monitored. The entry and exit for such Portals is usually side ways. The electronic system, designed essentially consists of powerful compact electronic circuits, comprising of three micro-controllers, a host of (32) 12C serial counters, other serial ADCs, DACs etc., apart from pulse processing, HV and LV circuits. Built-in embedded code has powerful fault diagnostics routines to show up failures in detector / detector electronics, HV, LV and other circuits apart from indicating contamination status, through visual and aural indications such as MIMIC, visual LCD display and individual channel counts etc. The Portal structural design consists of four individual SS members integrated, lead shielding assemblies (inside), on hinged support frames facilitate ease of assembling and dismantling of the structure. The detector arrangement is so arranged to have optimal uniform spread out, so as to record contamination of the whole body of the person being monitored. (author)

  20. Bunch compression efficiency of the femtosecond electron source at Chiang Mai University

    International Nuclear Information System (INIS)

    Thongbai, C.; Kusoljariyakul, K.; Saisut, J.

    2011-01-01

    A femtosecond electron source has been developed at the Plasma and Beam Physics Research Facility (PBP), Chiang Mai University (CMU), Thailand. Ultra-short electron bunches can be produced with a bunch compression system consisting of a thermionic cathode RF-gun, an alpha-magnet as a magnetic bunch compressor, and a linear accelerator as a post acceleration section. To obtain effective bunch compression, it is crucial to provide a proper longitudinal phase-space distribution at the gun exit matched to the subsequent beam transport system. Via beam dynamics calculations and experiments, we investigate the bunch compression efficiency for various RF-gun fields. The particle distribution at the RF-gun exit will be tracked numerically through the alpha-magnet and beam transport. Details of the study and results leading to an optimum condition for our system will be presented.

  1. Bunch compression efficiency of the femtosecond electron source at Chiang Mai University

    Science.gov (United States)

    Thongbai, C.; Kusoljariyakul, K.; Saisut, J.

    2011-07-01

    A femtosecond electron source has been developed at the Plasma and Beam Physics Research Facility (PBP), Chiang Mai University (CMU), Thailand. Ultra-short electron bunches can be produced with a bunch compression system consisting of a thermionic cathode RF-gun, an alpha-magnet as a magnetic bunch compressor, and a linear accelerator as a post acceleration section. To obtain effective bunch compression, it is crucial to provide a proper longitudinal phase-space distribution at the gun exit matched to the subsequent beam transport system. Via beam dynamics calculations and experiments, we investigate the bunch compression efficiency for various RF-gun fields. The particle distribution at the RF-gun exit will be tracked numerically through the alpha-magnet and beam transport. Details of the study and results leading to an optimum condition for our system will be presented.

  2. Efficient creation of electron vortex beams for high resolution STEM imaging.

    Science.gov (United States)

    Béché, A; Juchtmans, R; Verbeeck, J

    2017-07-01

    The recent discovery of electron vortex beams carrying quantised angular momentum in the TEM has led to an active field of research, exploring a variety of potential applications including the possibility of mapping magnetic states at the atomic scale. A prerequisite for this is the availability of atomic sized electron vortex beams at high beam current and mode purity. In this paper we present recent progress showing that by making use of the Aharonov-Bohm effect near the tip of a long single domain ferromagnetic Nickel needle, a very efficient aperture for the production of electron vortex beams can be realised. The aperture transmits more than 99% of all electrons and provides a vortex mode purity of up to 92%. Placing this aperture in the condenser plane of a state of the art Cs corrected microscope allows us to demonstrate atomic resolution HAADF STEM images with spatial resolution better than 1 Angström, in agreement with theoretical expectations and only slightly inferior to the performance of a non-vortex probe on the same instrument. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Computationally efficient description of relativistic electron beam transport in dense plasma

    Science.gov (United States)

    Polomarov, Oleg; Sefkov, Adam; Kaganovich, Igor; Shvets, Gennady

    2006-10-01

    A reduced model of the Weibel instability and electron beam transport in dense plasma is developed. Beam electrons are modeled by macro-particles and the background plasma is represented by electron fluid. Conservation of generalized vorticity and quasineutrality of the plasma-beam system are used to simplify the governing equations. Our approach is motivated by the conditions of the FI scenario, where the beam density is likely to be much smaller than the plasma density and the beam energy is likely to be very high. For this case the growth rate of the Weibel instability is small, making the modeling of it by conventional PICs exceedingly time consuming. The present approach does not require resolving the plasma period and only resolves a plasma collisionless skin depth and is suitable for modeling a long-time behavior of beam-plasma interaction. An efficient code based on this reduced description is developed and benchmarked against the LSP PIC code. The dynamics of low and high current electron beams in dense plasma is simulated. Special emphasis is on peculiarities of its non-linear stages, such as filament formation and merger, saturation and post-saturation field and energy oscillations. *Supported by DOE Fusion Science through grant DE-FG02-05ER54840.

  4. Electron efficiency of nZVI does not change with variation of environmental parameters

    International Nuclear Information System (INIS)

    Schöftner, Philipp; Waldner, Georg; Lottermoser, Werner; Stöger-Pollach, Michael; Freitag, Peter; Reichenauer, Thomas G.

    2015-01-01

    Nanoscale zero-valent iron particles (nZVI) are already applied for in-situ dechlorination of halogenated organic contaminants in the field. We performed batch experiments whereby trichloroethene (TCE) was dehalogenated by nZVI under different environmental conditions that are relevant in practice. The tested conditions include different ionic strengths, addition of polyelectrolytes (carboxymethylcellulose and ligninsulphonate), lowered temperature, dissolved oxygen and different particle contents. Particle properties were determined by Mössbauer spectroscopy, XRD, TEM, SEM, AAS and laser obscuration time measurements. TCE dehalogenation and H 2 evolution were decelerated by reduced ionic strength, addition of polyelectrolytes, temperature reduction, the presence of dissolved oxygen and reduced particle content. The partitioning of released electrons between reactions with the contaminant vs. with water (selectivity) was low, independent of the tested conditions. Basically out of hundred electrons that were released via nZVI oxidation only 3.1 ± 1.4 were used for TCE dehalogenation. Even lower selectivities were observed at TCE concentrations below 3.5 mg l −1 , hence particle modifications and/or combination of nZVI with other remediation technologies seem to be necessary to reach target concentrations for remediation. Our results suggest that selectivity is particle intrinsic and not as much condition dependent, hence particle synthesis and potential particle modifications of nZVI particles may be more important for optimization of the pollutant degradation rate, than tested environmental conditions. - Highlights: • We investigated the degradation kinetics of trichloroethene by zerovalent nanoiron particles. • Electron efficiency of the tested particles was very low (about 3%). • The tested environmental conditions had no significant influence on the degradation kinetics and electron efficiency. • We conclude that particle type is more important for

  5. Electron efficiency of nZVI does not change with variation of environmental parameters

    Energy Technology Data Exchange (ETDEWEB)

    Schöftner, Philipp, E-mail: philipp.schoeftner@ait.ac.at [AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, 3430 Tulln a.d. Donau (Austria); Waldner, Georg [AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, 3430 Tulln a.d. Donau (Austria); Lottermoser, Werner, E-mail: werner.lottermoser@sbg.ac.at [Salzburg University, FB Materialforschung und Physik, Hellbrunnerstr. 34, 5020 Salzburg (Austria); Stöger-Pollach, Michael, E-mail: stoeger@ustem.tuwien.ac.at [Technical University of Vienna, Universitäre Service-Einrichtung für Transmissionselektronenmikroskopie — USTEM (Austria); Freitag, Peter, E-mail: p.freitag@kellergrundbau.at [Keller Grundbau Ges. mbH, Mariahilfer Straße 127a, 1150 Vienna (Austria); Reichenauer, Thomas G., E-mail: thomas.reichenauer@ait.ac.at [AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, 3430 Tulln a.d. Donau (Austria)

    2015-12-01

    Nanoscale zero-valent iron particles (nZVI) are already applied for in-situ dechlorination of halogenated organic contaminants in the field. We performed batch experiments whereby trichloroethene (TCE) was dehalogenated by nZVI under different environmental conditions that are relevant in practice. The tested conditions include different ionic strengths, addition of polyelectrolytes (carboxymethylcellulose and ligninsulphonate), lowered temperature, dissolved oxygen and different particle contents. Particle properties were determined by Mössbauer spectroscopy, XRD, TEM, SEM, AAS and laser obscuration time measurements. TCE dehalogenation and H{sub 2} evolution were decelerated by reduced ionic strength, addition of polyelectrolytes, temperature reduction, the presence of dissolved oxygen and reduced particle content. The partitioning of released electrons between reactions with the contaminant vs. with water (selectivity) was low, independent of the tested conditions. Basically out of hundred electrons that were released via nZVI oxidation only 3.1 ± 1.4 were used for TCE dehalogenation. Even lower selectivities were observed at TCE concentrations below 3.5 mg l{sup −1}, hence particle modifications and/or combination of nZVI with other remediation technologies seem to be necessary to reach target concentrations for remediation. Our results suggest that selectivity is particle intrinsic and not as much condition dependent, hence particle synthesis and potential particle modifications of nZVI particles may be more important for optimization of the pollutant degradation rate, than tested environmental conditions. - Highlights: • We investigated the degradation kinetics of trichloroethene by zerovalent nanoiron particles. • Electron efficiency of the tested particles was very low (about 3%). • The tested environmental conditions had no significant influence on the degradation kinetics and electron efficiency. • We conclude that particle type is more

  6. Efficient and Flexible Computation of Many-Electron Wave Function Overlaps.

    Science.gov (United States)

    Plasser, Felix; Ruckenbauer, Matthias; Mai, Sebastian; Oppel, Markus; Marquetand, Philipp; González, Leticia

    2016-03-08

    A new algorithm for the computation of the overlap between many-electron wave functions is described. This algorithm allows for the extensive use of recurring intermediates and thus provides high computational efficiency. Because of the general formalism employed, overlaps can be computed for varying wave function types, molecular orbitals, basis sets, and molecular geometries. This paves the way for efficiently computing nonadiabatic interaction terms for dynamics simulations. In addition, other application areas can be envisaged, such as the comparison of wave functions constructed at different levels of theory. Aside from explaining the algorithm and evaluating the performance, a detailed analysis of the numerical stability of wave function overlaps is carried out, and strategies for overcoming potential severe pitfalls due to displaced atoms and truncated wave functions are presented.

  7. Probabilities and energies to obtain the counting efficiency of electron-capture nuclides. KLMN model

    International Nuclear Information System (INIS)

    Galiano, G.; Grau, A.

    1994-01-01

    An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electro capture in the counting efficiency when the atomic number of the nuclide is high. (Author)

  8. Liquid scintillation counting efficiency in three photomultiplier systems. Pure electron capture

    International Nuclear Information System (INIS)

    Los Arcos, J. M.; Grau Carles, A.; Grau Malonda, A.

    1990-01-01

    The tables of counting efficiency as a function of the figure of merit for a liquid scintillation counting system working with three phototubes are presented. The evaluation has been carried out for a Toluene-based scintillator with 5, 10 and 15 ml column, and 19 different radionuclides decaying by pure electron capture: 37Ar 41Ca, 49V, 53 Mn, 55Fe, 59Ni, 68Ge 7iGe, 82Sr, 97Tc, 118Te, 131CS, 137La, 140Ca, 157Tb, 165Er, 193Pt, 194Hg, 205Pb. (Author) 22 refs

  9. Numerically robust and efficient nonlocal electron transport in 2D DRACO simulations

    Science.gov (United States)

    Cao, Duc; Chenhall, Jeff; Moses, Greg; Delettrez, Jacques; Collins, Tim

    2013-10-01

    An improved implicit algorithm based on Schurtz, Nicolai and Busquet (SNB) algorithm for nonlocal electron transport is presented. Validation with direct drive shock timing experiments and verification with the Goncharov nonlocal model in 1D LILAC simulations demonstrate the viability of this efficient algorithm for producing 2D lagrangian radiation hydrodynamics direct drive simulations. Additionally, simulations provide strong incentive to further modify key parameters within the SNB theory, namely the ``mean free path.'' An example 2D polar drive simulation to study 2D effects of the nonlocal flux as well as mean free path modifications will also be presented. This research was supported by the University of Rochester Laboratory for Laser Energetics.

  10. Accuracy and efficiency of radiologists reporting CT studies from a multiscreen electronic workstation

    International Nuclear Information System (INIS)

    Foley, W.D.; Lawson, T.L.; Erickson, S.J.

    1988-01-01

    This paper describes a limited picture archiving communication system linking, a via fiber optic cable, two computed tomographic (CT) scanners, and a double-screen (1,000-line monitors) display station with a 600-megabyte image memory evaluated for accuracy and efficiency in the generation of a radiology report. Twenty preselected CT studies (an average of 30 images per study, ten with prior examination for comparison) in cases with pathologically or clinically proved diagnoses were read by five radiologists, in random order, from both the electronic display console and conventional multiformat images. All cases were reread after 1-month interval in a different random order viewing sequence and the opposite viewing modality

  11. An Efficient, “Burn in” Free Organic Solar Cell Employing a Nonfullerene Electron Acceptor

    KAUST Repository

    Cha, Hyojung

    2017-06-28

    A comparison of the efficiency, stability, and photophysics of organic solar cells employing poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3\\'″-di(2-octyldodecyl)-2,2\\';5\\',2″;5″,2\\'″-quaterthiophen-5,5\\'″-diyl)] (PffBT4T-2OD) as a donor polymer blended with either the nonfullerene acceptor EH-IDTBR or the fullerene derivative, [6,6]-phenyl C71 butyric acid methyl ester (PC71 BM) as electron acceptors is reported. Inverted PffBT4T-2OD:EH-IDTBR blend solar cell fabricated without any processing additive achieves power conversion efficiencies (PCEs) of 9.5 ± 0.2%. The devices exhibit a high open circuit voltage of 1.08 ± 0.01 V, attributed to the high lowest unoccupied molecular orbital (LUMO) level of EH-IDTBR. Photoluminescence quenching and transient absorption data are employed to elucidate the ultrafast kinetics and efficiencies of charge separation in both blends, with PffBT4T-2OD exciton diffusion kinetics within polymer domains, and geminate recombination losses following exciton separation being identified as key factors determining the efficiency of photocurrent generation. Remarkably, while encapsulated PffBT4T-2OD:PC71 BM solar cells show significant efficiency loss under simulated solar irradiation (“burn in” degradation) due to the trap-assisted recombination through increased photoinduced trap states, PffBT4T-2OD:EH-IDTBR solar cell shows negligible burn in efficiency loss. Furthermore, PffBT4T-2OD:EH-IDTBR solar cells are found to be substantially more stable under 85 °C thermal stress than PffBT4T-2OD:PC71BM devices.

  12. An Efficient, "Burn in" Free Organic Solar Cell Employing a Nonfullerene Electron Acceptor.

    Science.gov (United States)

    Cha, Hyojung; Wu, Jiaying; Wadsworth, Andrew; Nagitta, Jade; Limbu, Saurav; Pont, Sebastian; Li, Zhe; Searle, Justin; Wyatt, Mark F; Baran, Derya; Kim, Ji-Seon; McCulloch, Iain; Durrant, James R

    2017-09-01

    A comparison of the efficiency, stability, and photophysics of organic solar cells employing poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3'″-di(2-octyldodecyl)-2,2';5',2″;5″,2'″-quaterthiophen-5,5'″-diyl)] (PffBT4T-2OD) as a donor polymer blended with either the nonfullerene acceptor EH-IDTBR or the fullerene derivative, [6,6]-phenyl C 71 butyric acid methyl ester (PC 71 BM) as electron acceptors is reported. Inverted PffBT4T-2OD:EH-IDTBR blend solar cell fabricated without any processing additive achieves power conversion efficiencies (PCEs) of 9.5 ± 0.2%. The devices exhibit a high open circuit voltage of 1.08 ± 0.01 V, attributed to the high lowest unoccupied molecular orbital (LUMO) level of EH-IDTBR. Photoluminescence quenching and transient absorption data are employed to elucidate the ultrafast kinetics and efficiencies of charge separation in both blends, with PffBT4T-2OD exciton diffusion kinetics within polymer domains, and geminate recombination losses following exciton separation being identified as key factors determining the efficiency of photocurrent generation. Remarkably, while encapsulated PffBT4T-2OD:PC 71 BM solar cells show significant efficiency loss under simulated solar irradiation ("burn in" degradation) due to the trap-assisted recombination through increased photoinduced trap states, PffBT4T-2OD:EH-IDTBR solar cell shows negligible burn in efficiency loss. Furthermore, PffBT4T-2OD:EH-IDTBR solar cells are found to be substantially more stable under 85 °C thermal stress than PffBT4T-2OD:PC 71 BM devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. The Portuguese Climate Portal

    Science.gov (United States)

    Gomes, Sandra; Deus, Ricardo; Nogueira, Miguel; Viterbo, Pedro; Miranda, Miguel; Antunes, Sílvia; Silva, Alvaro; Miranda, Pedro

    2016-04-01

    The Portuguese Local Warming Website (http://portaldoclima.pt) has been developed in order to support the society in Portugal in preparing for the adaptation to the ongoing and future effects of climate change. The climate portal provides systematic and easy access to authoritative scientific data ready to be used by a vast and diverse user community from different public and private sectors, key players and decision makers, but also to high school students, contributing to the increase in knowledge and awareness on climate change topics. A comprehensive set of regional climate variables and indicators are computed, explained and graphically presented. Variables and indicators were built in agreement with identified needs after consultation of the relevant social partners from different sectors, including agriculture, water resources, health, environment and energy and also in direct cooperation with the Portuguese National Strategy for Climate Change Adaptation (ENAAC) group. The visual interface allows the user to dynamically interact, explore, quickly analyze and compare, but also to download and import the data and graphics. The climate variables and indicators are computed from state-of-the-art regional climate model (RCM) simulations (e.g., CORDEX project), at high space-temporal detail, allowing to push the limits of the projections down to local administrative regions (NUTS3) and monthly or seasonal periods, promoting local adaptation strategies. The portal provides both historical data (observed and modelled for the 1971-2000 period) and future climate projections for different scenarios (modelled for the 2011-2100 period). A large effort was undertaken in order to quantify the impacts of the risk of extreme events, such as heavy rain and flooding, droughts, heat and cold waves, and fires. Furthermore the different climate scenarios and the ensemble of RCM models, with high temporal (daily) and spatial (~11km) detail, is taken advantage in order to

  14. Barriers and Facilitators Affecting Patient Portal Implementation from an Organizational Perspective: Qualitative Study.

    Science.gov (United States)

    Kooij, Laura; Groen, Wim G; van Harten, Wim H

    2018-05-11

    The number of patient portals is rising, and although portals can have positive effects, their implementation has major impacts on the providing health care institutions. However, little is known about the organizational factors affecting successful implementation. Knowledge of the specific barriers to and facilitators of various stakeholders is likely to be useful for future implementations. The objective of this study was to identify the barriers to and facilitators of patient portal implementation facing various stakeholders within hospital organizations in the Netherlands. Purposive sampling was used to select hospitals of various types. A total of 2 university medical centers, 3 teaching hospitals, and 2 general hospitals were included. For each, 3 stakeholders were interviewed: (1) medical professionals, (2) managers, and (3) information technology employees. In total, 21 semistructured interviews were conducted using the Grol and Wensing model, which describes barriers to and facilitators of change in health care practice at 6 levels: (1) innovation; (2) individual professional; (3) patient; (4) social context; (5) organizational context; and (6) economic and political context. Two researchers independently selected and coded quotes by applying this model using a (deductive) directed content approach. Additional factors related to technical and portal characteristics were added using the model of McGinn et al, developed for implementation of electronic health records. In total, we identified 376 quotes, 26 barriers, and 28 facilitators. Thirteen barriers and 12 facilitators were common for all stakeholder groups. The facilitators' perceived usefulness (especially less paperwork) was mentioned by all the stakeholders, followed by subjects' positive attitude. The main barriers were lack of resources (namely, lack of staff and materials), financial difficulties (especially complying with high costs, lack of reimbursements), and guaranteeing privacy and security

  15. Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun

    Energy Technology Data Exchange (ETDEWEB)

    Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

    2010-05-23

    RF electron guns with a strained super lattice GaAs cathode can generate polarized electron beam of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface. In a normal conducting RF gun, the extremely high vaccum required by these cathodes can not be met. We report on an experiment with a superconducting SRF gun, which can maintain a vacuum of nearly 10-12 torr because of cryo-pumping at the temperature of 4.2K. With conventional activation, we obtained a QE of 3% at 532 nm, with lifetime of nearly 3 days in the preparation chamber. We plan to use this cathode in a 1.3 GHz 1/2 cell SRF gun to study its performance. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper. Future particle accelerators such as eRHIC and ILC require high brightness, high current polarized electrons Recently, using a superlattice crystal, the maximum polarization of 95% was reached. Activation with Cs,O lowers the electron affinity and makes it energetically possible for all the electrons excited in to the conduction band and reach the surface to escape into the vacuum. Presently the polarized electron sources are based on DC gun, such as that at the CEBAF at Jlab. In these devices, the life time of the cathode is extended due to the reduced back bombardment in their UHV conditions. However, the low accelerating gradient of the DC guns lead to poor longitudinal emittance. The higher accelerating gradient of the RF gun generates low emittance beams. Superconducting RF guns combine the excellent vacuum conditions of the DC guns with the higher accelerating gradients of the RF guns and provide potentially a long lived cathode with very low transverse and longitudinal emittance. In our work at BNL, we successfully activated the GaAs. The quantum efficient is 3% at 532 nm and is

  16. Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun

    International Nuclear Information System (INIS)

    Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

    2010-01-01

    RF electron guns with a strained super lattice GaAs cathode can generate polarized electron beam of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface. In a normal conducting RF gun, the extremely high vaccum required by these cathodes can not be met. We report on an experiment with a superconducting SRF gun, which can maintain a vacuum of nearly 10-12 torr because of cryo-pumping at the temperature of 4.2K. With conventional activation, we obtained a QE of 3% at 532 nm, with lifetime of nearly 3 days in the preparation chamber. We plan to use this cathode in a 1.3 GHz 1/2 cell SRF gun to study its performance. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper. Future particle accelerators such as eRHIC and ILC require high brightness, high current polarized electrons Recently, using a superlattice crystal, the maximum polarization of 95% was reached. Activation with Cs,O lowers the electron affinity and makes it energetically possible for all the electrons excited in to the conduction band and reach the surface to escape into the vacuum. Presently the polarized electron sources are based on DC gun, such as that at the CEBAF at Jlab. In these devices, the life time of the cathode is extended due to the reduced back bombardment in their UHV conditions. However, the low accelerating gradient of the DC guns lead to poor longitudinal emittance. The higher accelerating gradient of the RF gun generates low emittance beams. Superconducting RF guns combine the excellent vacuum conditions of the DC guns with the higher accelerating gradients of the RF guns and provide potentially a long lived cathode with very low transverse and longitudinal emittance. In our work at BNL, we successfully activated the GaAs. The quantum efficient is 3% at 532 nm and is expected

  17. Comparison of daily megavoltage electronic portal imaging or kilovoltage imaging with marker seeds to ultrasound imaging or skin marks for prostate localization and treatment positioning in patients with prostate cancer

    International Nuclear Information System (INIS)

    Serago, Christopher F.; Buskirk, Steven J.; Igel, Todd C.; Gale, Ashley A.; Serago, Nicole E.; Earle, John D.

    2006-01-01

    Purpose: To compare the accuracy of imaging modalities, immobilization, localization, and positioning techniques in patients with prostate cancer. Methods and Materials: Thirty-five patients with prostate cancer had gold marker seeds implanted transrectally and were treated with fractionated radiotherapy. Twenty of the 35 patients had limited immobilization; the remaining had a vacuum-based immobilization. Patient positioning consisted of alignment with lasers to skin marks, ultrasound or kilovoltage X-ray imaging, optical guidance using infrared reflectors, and megavoltage electronic portal imaging (EPI). The variance of each positioning technique was compared to the patient position determined from the pretreatment EPI. Results: With limited immobilization, the average difference between the skin marks' laser position and EPI pretreatment position is 9.1 ± 5.3 mm, the average difference between the skin marks' infrared position and EPI pretreatment position is 11.8 ± 7.2 mm, the average difference between the ultrasound position and EPI pretreatment position is 7.0 ± 4.6 mm, the average difference between kV imaging and EPI pretreatment position is 3.5 ± 3.1 mm, and the average intrafraction movement during treatment is 3.4 ± 2.7 mm. For the patients with the vacuum-style immobilization, the average difference between the skin marks' laser position and EPI pretreatment position is 10.7 ± 4.6 mm, the average difference between kV imaging and EPI pretreatment position is 1.9 ± 1.5 mm, and the average intrafraction movement during treatment is 2.1 ± 1.5 mm. Conclusions: Compared with use of skin marks, ultrasound imaging for positioning provides an increased degree of agreement to EPI-based positioning, though not as favorable as kV imaging fiducial seeds. Intrafraction movement during treatment decreases with improved immobilization

  18. Pre-treatment verification of RapidArc® using Electronic Portal Imaging Device; Verificacao pre-tratamento de RapidArc® utilizando Dispositivo Eletronico de Imagem Porta

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Marilia B.; Ferreira, Anne Caroline M.; Bittencourt, Guilherme R.; Pirani, Luis F.; Silveira, Thiago B., E-mail: mbeckerlima@gmail.com [Instituto Nacional do Cancer (INCA), Rio de Janeiro, RJ (Brazil)

    2012-12-15

    The RapidArc® is a novel but widespread technique to achieve intensity modulated beams. One of the major challenges concerning this technique is the pretreatment verification process. The aim of this paper was to analyze the viability of the Electronic Portal Imaging Device (EPID) used to perform the verification of RapidArc® using the Sun Nuclear SNC Patient software enable to EPID dose conversion (EPIDose license) and compare its results with punctual dose measurements against a low volume ion chamber. There were analyze five RapidArc® planning, evaluating, separately, planar and punctual doses for each arc. For punctual measurements was used a 0,15 cm³ volume ion chamber and the planar distributions, in Calibration Units (CU), were acquired using the EPID and then converted to absolute dose in centigray through EPIDose. The predicted doses were calculated using the AAA algorithm in Eclipse treatment planning system, version 8.6. The planar comparisons, performed in SNC Patient, employed the Gamma Index tool with a 4% dose difference, 4 mm distance to agreement and 20% threshold. The evaluation of punctual dose was defined by calculating deviations between predicted and measured doses. The mean approval percentage in planar distributions was 94.8% and the average deviation in punctual dose was -1.2%. The use of EPID for RapidArc® pre-treatment verification proved to be feasible and showed good sensibility, because of its high spatial resolution. However one must consider the uncertainty of the method. (author)

  19. Digitalization and networking of analog simulators and portal images

    Energy Technology Data Exchange (ETDEWEB)

    Pesznyak, C.; Zarand, P.; Mayer, A. [Uzsoki Hospital, Budapest (Hungary). Inst. of Oncoradiology

    2007-03-15

    Background: Many departments have analog simulators and irradiation facilities (especially cobalt units) without electronic portal imaging. Import of the images into the R and V (Record and Verify) system is required. Material and Methods: Simulator images are grabbed while portal films scanned by using a laser scanner and both converted into DICOM RT (Digital Imaging and Communications in Medicine Radiotherapy) images. Results: Image intensifier output of a simulator and portal films are converted to DICOM RT images and used in clinical practice. The simulator software was developed in cooperation at the authors' hospital. Conclusion: The digitalization of analog simulators is a valuable updating in clinical use replacing screen-film technique. Film scanning and digitalization permit the electronic archiving of films. Conversion into DICOM RT images is a precondition of importing to the R and V system. (orig.)

  20. Digitalization and networking of analog simulators and portal images.

    Science.gov (United States)

    Pesznyák, Csilla; Zaránd, Pál; Mayer, Arpád

    2007-03-01

    Many departments have analog simulators and irradiation facilities (especially cobalt units) without electronic portal imaging. Import of the images into the R&V (Record & Verify) system is required. Simulator images are grabbed while portal films scanned by using a laser scanner and both converted into DICOM RT (Digital Imaging and Communications in Medicine Radiotherapy) images. Image intensifier output of a simulator and portal films are converted to DICOM RT images and used in clinical practice. The simulator software was developed in cooperation at the authors' hospital. The digitalization of analog simulators is a valuable updating in clinical use replacing screen-film technique. Film scanning and digitalization permit the electronic archiving of films. Conversion into DICOM RT images is a precondition of importing to the R&V system.

  1. Echographic and hemodynamic parameters in patients with hepatic cirrhosis and portal hypertension

    International Nuclear Information System (INIS)

    Rikhsieva, L.Eh.; Akhmedzhanova, Sh.Sh.; Myasnik, B.N.; Khodzhibekov, M.Kh.

    1989-01-01

    The efficiency of combined echoradionuclide investigation for the identification of the severity of portal hypertension and the determination of clear-cut criteria for the differentiation of stages of portal hypertension with reference to functional potentials of renal hemodynamics and systemic circulation at large is demonstrated

  2. Congestive index of portal vein

    International Nuclear Information System (INIS)

    Kim, Won Ho; Kim, H. K.; Lee, S. C.; Han, S. H.; Han, K. H.; Chung, J. B.; Choi, H. J.

    1989-01-01

    In patients with portal hypertension, the blood flow volume is maintained despite decreased blood flow velocity due to enlargement of the vascular cross sectional area. Thus, the 'congestion index' of the portal vein, which is the ratio between the cross sectional area (cm2) and the blood flow velocity (cm/sec) determined by a Doppler ultrasonography, may be a sensitive index by which to assess portal hypertension. We performed Doppler ultrasonography on 24 normal subjects, 14 patients with biopsy proved chronic active hepatitis and 55 patients with liver cirrhosis in order to assess the diagnostic value of the congestion index. The cross sectional area of the portal vein was significantly enlarged and the mean blood flow velocity was significantly reduced in patients with liver cirrhosis compared with controls. However, the blood flow volume was no difference. The congestion index of the portal vein was significantly increased in patients with liver cirrhosis (0.113+0.035) compared with patients with chronic active hepatitis(0.078+0.029) (p<0.001) and controls (0.053+0.016) (p<0.001). The sensitivity, specificity and predictability of the congestion index for detection of patients with the cirrhosis of the liver were 76.4%, 100% and 100% respectively, when the normal range was set at mean+2SD. The results suggest that the congestion index of the portal vein may pla a significant role in diagnosis of portal hypertensive patients

  3. Order enables efficient electron-hole separation at an organic heterojunction with a small energy loss

    KAUST Repository

    Menke, S. Matthew

    2018-01-12

    Donor–acceptor organic solar cells often show low open-circuit voltages (VOC) relative to their optical energy gap (Eg) that limit power conversion efficiencies to ~12%. This energy loss is partly attributed to the offset between Eg and that of intermolecular charge transfer (CT) states at the donor–acceptor interface. Here we study charge generation occurring in PIPCP:PC61BM, a system with a very low driving energy for initial charge separation (Eg−ECT ~ 50 meV) and a high internal quantum efficiency (ηIQE ~ 80%). We track the strength of the electric field generated between the separating electron-hole pair by following the transient electroabsorption optical response, and find that while localised CT states are formed rapidly (<100 fs) after photoexcitation, free charges are not generated until 5 ps after photogeneration. In PIPCP:PC61BM, electronic disorder is low (Urbach energy <27 meV) and we consider that free charge separation is able to outcompete trap-assisted non-radiative recombination of the CT state.

  4. A computationally efficient moment-preserving Monte Carlo electron transport method with implementation in Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, D.A., E-mail: ddixon@lanl.gov [Los Alamos National Laboratory, P.O. Box 1663, MS P365, Los Alamos, NM 87545 (United States); Prinja, A.K., E-mail: prinja@unm.edu [Department of Nuclear Engineering, MSC01 1120, 1 University of New Mexico, Albuquerque, NM 87131-0001 (United States); Franke, B.C., E-mail: bcfrank@sandia.gov [Sandia National Laboratories, Albuquerque, NM 87123 (United States)

    2015-09-15

    This paper presents the theoretical development and numerical demonstration of a moment-preserving Monte Carlo electron transport method. Foremost, a full implementation of the moment-preserving (MP) method within the Geant4 particle simulation toolkit is demonstrated. Beyond implementation details, it is shown that the MP method is a viable alternative to the condensed history (CH) method for inclusion in current and future generation transport codes through demonstration of the key features of the method including: systematically controllable accuracy, computational efficiency, mathematical robustness, and versatility. A wide variety of results common to electron transport are presented illustrating the key features of the MP method. In particular, it is possible to achieve accuracy that is statistically indistinguishable from analog Monte Carlo, while remaining up to three orders of magnitude more efficient than analog Monte Carlo simulations. Finally, it is shown that the MP method can be generalized to any applicable analog scattering DCS model by extending previous work on the MP method beyond analytical DCSs to the partial-wave (PW) elastic tabulated DCS data.

  5. Order enables efficient electron-hole separation at an organic heterojunction with a small energy loss

    KAUST Repository

    Menke, S. Matthew; Cheminal, Alexandre; Conaghan, Patrick; Ran, Niva A.; Greehnam, Neil C.; Bazan, Guillermo C.; Nguyen, Thuc-Quyen; Rao, Akshay; Friend, Richard H.

    2018-01-01

    Donor–acceptor organic solar cells often show low open-circuit voltages (VOC) relative to their optical energy gap (Eg) that limit power conversion efficiencies to ~12%. This energy loss is partly attributed to the offset between Eg and that of intermolecular charge transfer (CT) states at the donor–acceptor interface. Here we study charge generation occurring in PIPCP:PC61BM, a system with a very low driving energy for initial charge separation (Eg−ECT ~ 50 meV) and a high internal quantum efficiency (ηIQE ~ 80%). We track the strength of the electric field generated between the separating electron-hole pair by following the transient electroabsorption optical response, and find that while localised CT states are formed rapidly (<100 fs) after photoexcitation, free charges are not generated until 5 ps after photogeneration. In PIPCP:PC61BM, electronic disorder is low (Urbach energy <27 meV) and we consider that free charge separation is able to outcompete trap-assisted non-radiative recombination of the CT state.

  6. The NUCLEONICA Nuclear Science Portal

    International Nuclear Information System (INIS)

    Magill, Joseph; Dreher, Raymond

    2009-01-01

    NUCLEONICA (www.nucleonica.net) is a new nuclear science web portal which provides a customisable, integrated environment and collaboration platform using the latest internet 'Web 2.0' technology. NUCLEONICA is aimed at professionals, academics and students working in nuclear power, health physics and radiation protection, nuclear and radio-chemistry, and astrophysics. A unique feature of the portal is the wide range of user friendly web-based nuclear science applications. The portal is also ideal for education and training purposes and as a knowledge management platform to preserve nuclear knowledge built up over many decades.

  7. The Higgs Portal and Cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Assamagan, Ketevi [Brookhaven National Lab. (BNL), Upton, NY (United States); Chen, Chien-Yi [Perimeter Inst. for Theoretical Physics, Waterloo, ON (Canada); Univ. of Victoria, BC (Canada); Chou, John Paul [Rutgers Univ., Piscataway, NJ (United States); Curtin, David [Univ. of Maryland, College Park, MD (United States); Fedderke, Michael A. [Univ. of Chicago, IL (United States); Gershtein, Yuri [Rutgers Univ., Piscataway, NJ (United States); He, Xiao-Gang [Shanghai Jiao Tong Univ. (China); Klute, Markus [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Kozaczuk, Jonathon [TRIUMF, Vancouver, BC (Canada); Kotwal, Ashutosh [Duke Univ., Durham, NC (United States); Lowette, Steven [Vrije Univ., Brussels (Belgium); No, Jose Miguel [Univ. of Sussex, Brighton (United Kingdom); Plehn, Tilman [Heidelberg Univ. (Germany); Qian, Jianming [Univ. of Michigan, Ann Arbor, MI (United States); Ramsey-Musolf, Michael [Univ. of Massachusetts, Amherst, MA (United States); Safonov, Alexei [Texas A & M Univ., College Station, TX (United States); Shelton, Jessie [Univ. of Illinois, Urbana-Champaign, IL (United States); Spannowsky, Michael [Durham Univ. (United Kingdom); Su, Shufang [Univ. of Arizona, Tucson, AZ (United States); Walker, Devin G. E. [Univ. of Washington, Seattle, WA (United States); Willocq, Stephane [Univ. of Massachusetts, Amherst, MA (United States); Winslow, Peter [Univ. of Massachusetts, Amherst, MA (United States)

    2016-04-18

    Higgs portal interactions provide a simple mechanism for addressing two open problems in cosmology: dark matter and the baryon asymmetry. In the latter instance, Higgs portal interactions may contain the ingredients for a strong first-order electroweak phase transition as well as new CP-violating interactions as needed for electroweak baryogenesis. These interactions may also allow for a viable dark matter candidate. We survey the opportunities for probing the Higgs portal as it relates to these questions in cosmology at the LHC and possible future colliders.

  8. Search Engine For Ebook Portal

    Directory of Open Access Journals (Sweden)

    Prashant Kanade

    2017-05-01

    Full Text Available The purpose of this paper is to establish the textual analytics involved in developing a search engine for an ebook portal. We have extracted our dataset from Project Gutenberg using a robot harvester. Textual Analytics is used for efficient search retrieval. The entire dataset is represented using Vector Space Model where each document is a vector in the vector space. Further for computational purposes we represent our dataset in the form of a Term Frequency- Inverse Document Frequency tf-idf matrix. The first step involves obtaining the most coherent sequence of words of the search query entered. The entered query is processed using Front End algorithms this includes-Spell Checker Text Segmentation and Language Modeling. Back End processing includes Similarity Modeling Clustering Indexing and Retrieval. The relationship between documents and words is established using cosine similarity measured between the documents and words in Vector Space. Clustering performed is used to suggest books that are similar to the search query entered by the user. Lastly the Lucene Based Elasticsearch engine is used for indexing on the documents. This allows faster retrieval of data. Elasticsearch returns a dictionary and creates a tf-idf matrix. The processed query is compared with the dictionary obtained and tf-idf matrix is used to calculate the score for each match to give most relevant result.

  9. An empirical determination of the production efficiency for auroral 6300 AA emmission by energetic electrons

    International Nuclear Information System (INIS)

    Winningham, J.D.; Bunn, F.E.; Thirkettle, F.W.; Shepherd, G.G.

    1979-06-01

    Auroral data from the Soft Particle Spectrometer and the Red Line Photometer on the ISIS-2 spacecraft have been selected to form an electron energy flux and optical auroral emission data base. The energy fluxes are stored as integrated fluxes over four energy bands, and the corresponding stored optical emission rates are corrected for airglow and for albedo. Because of the variety of electron energy spectra represented in the data base it was possible to perform a regression analysis that yielded the production efficiency for the production of emission for each of the four bands. While the results of this analysis are interesting to compare with theoretical predictions of 6300 AA excitation processes, these statistical results are not as precise as the comparisons of individual experiments where all parameters, such as the atmospheric composition and temperature profiles are measured. The significance of this approach is that it permits a multiparameter description of an electron energy spectrum, and its relationship to a specific optical emission, by purely empirical means. This is particularly useful in the interpretation of ISIS-2 data from the instruments which provided the results, but should find further application in optical-particle auroral studies. (author)

  10. High efficiency charge recuperation for electron beams of MeV energies

    International Nuclear Information System (INIS)

    MacLachlan, J.A.

    1996-05-01

    Electron cooling of ion beams with energies of some GeV per nucleon requires high-quality electron beams of MeV energies and currents as high as several amperes. The enormous beam power dictates that the beam current be returned to the high voltage terminal which provides the accelerating potential. The beam is returned to a carefully designed collector within the terminal and biased a few kV positive with respect to it. Thus the load on the HV supply is only the accelerating potential times the sum of the beam current loss and the current used to maintain a graded potential on the accelerating structure. If one employs an electrostatic HV supply like a Van de Graaff with maximum charging current of a few hundred microA, the permissible fractional loss is ∼ 10 -4 . During the 15 years or so the concept of medium energy electron cooling has been evolving, the need to demonstrate the practicability of such high efficiency beam recovery has been recognized. This paper will review some experimental tests and further experiments which have been proposed. The design and status are presented for a new re-circulation experiment at 2 MV being carried out by Fermilab at National Electrostatics Corp

  11. High Efficiency Inverted Organic Solar Cells with a Neutral Fulleropyrrolidine Electron Collecting Interlayer

    KAUST Repository

    Xu, Weidong; Yan, Congfei; Kan, Zhipeng; Wang, Yang; Lai, Wen-Yong; Huang, Wei

    2016-01-01

    A novel fulleropyrrolidine derivative, named as FPNOH, was designed, synthesized and utilized as an efficient electron-collecting (EC) layer for inverted organic solar cells (i-OSCs). The grafted diethanolamino-polar moieties can not only trigger its function as an EC interlayer, but also induce orthogonal solubility that guarantees subsequent multi-layer processing without interfacial mixing. A higher power conversion efficiency (PCE) value of 8.34% was achieved for i-OSC devices with ITO/FPNOH EC electrode, compared to that of the sol-gel ZnO based reference devices with an optimized PCE value of 7.92%. High efficiency exceeding 7.7% was still achieved even for the devices with a relatively thick PFNOH film (16.9 nm). It is worthwhile to mention that this kind of material exhibits less thickness dependent performance, in contrast to widely utilized p-type conjugated polyelectrolytes (CPEs) as well as the non-conjugated polyelectrolytes (NCPEs). Further investigation on illuminating intensity dependent parameters revealed the role of FPNOH in reducing interfacial traps-induced recombination at ITO/active layer interface.

  12. High Efficiency Inverted Organic Solar Cells with a Neutral Fulleropyrrolidine Electron Collecting Interlayer

    KAUST Repository

    Xu, Weidong

    2016-05-20

    A novel fulleropyrrolidine derivative, named as FPNOH, was designed, synthesized and utilized as an efficient electron-collecting (EC) layer for inverted organic solar cells (i-OSCs). The grafted diethanolamino-polar moieties can not only trigger its function as an EC interlayer, but also induce orthogonal solubility that guarantees subsequent multi-layer processing without interfacial mixing. A higher power conversion efficiency (PCE) value of 8.34% was achieved for i-OSC devices with ITO/FPNOH EC electrode, compared to that of the sol-gel ZnO based reference devices with an optimized PCE value of 7.92%. High efficiency exceeding 7.7% was still achieved even for the devices with a relatively thick PFNOH film (16.9 nm). It is worthwhile to mention that this kind of material exhibits less thickness dependent performance, in contrast to widely utilized p-type conjugated polyelectrolytes (CPEs) as well as the non-conjugated polyelectrolytes (NCPEs). Further investigation on illuminating intensity dependent parameters revealed the role of FPNOH in reducing interfacial traps-induced recombination at ITO/active layer interface.

  13. Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

    International Nuclear Information System (INIS)

    Ostroumov, P. N.; Barcikowski, A.; Dickerson, C. A.; Perry, A.; Sharamentov, S. I.; Vondrasek, R. C.; Zinkann, G. P.; Pikin, A. I.

    2015-01-01

    The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz

  14. Electron Beam Evaporated TiO2 Layer for High Efficiency Planar Perovskite Solar Cells on Flexible Polyethylene Terephthalate Substrates

    KAUST Repository

    Qiu, Weiming; Paetzold, Ulrich W; Gehlhaar, Robert; Smirnov, Vladimir; Boyen, Hans-Gerd; Tait, Jeffrey Gerhart; Conings, Bert; Zhang, Weimin; Nielsen, Christian; McCulloch, Iain; Froyen, Ludo; Heremans, Paul; Cheyns, David

    2015-01-01

    The TiO2 layer made by electron beam (e-beam) induced evaporation is demonstrated as electron transport layer (ETL) in high efficiency planar junction perovskite solar cells. The temperature of the substrate and the thickness of the TiO2 layer can

  15. Quick, efficient and effective patient-specific intensity-modulated radiation therapy quality assurance using log file and electronic portal imaging device

    Directory of Open Access Journals (Sweden)

    Rajesh Kumar

    2017-01-01

    Conclusions: The methodology demonstrated can be used for establishing the accuracy of trajectory log data and for independent routine IMRT QA by generating single number like gamma index to indicate pass or fail of an IMRT treatment plan. The QA indices such as numbers of occurrences of ≥2 mm error in LPS are found more than 5% of total number of occurrences; the dosimetric review of planned treatment is advisable.

  16. The Electronic Patient Reported Outcome Tool: Testing Usability and Feasibility of a Mobile App and Portal to Support Care for Patients With Complex Chronic Disease and Disability in Primary Care Settings

    Science.gov (United States)

    Gill, Ashlinder; Khan, Anum Irfan; Hans, Parminder Kaur; Kuluski, Kerry; Cott, Cheryl

    2016-01-01

    Background People experiencing complex chronic disease and disability (CCDD) face some of the greatest challenges of any patient population. Primary care providers find it difficult to manage multiple discordant conditions and symptoms and often complex social challenges experienced by these patients. The electronic Patient Reported Outcome (ePRO) tool is designed to overcome some of these challenges by supporting goal-oriented primary care delivery. Using the tool, patients and providers collaboratively develop health care goals on a portal linked to a mobile device to help patients and providers track progress between visits. Objectives This study tested the usability and feasibility of adopting the ePRO tool into a single interdisciplinary primary health care practice in Toronto, Canada. The Fit between Individuals, Fask, and Technology (FITT) framework was used to guide our assessment and explore whether the ePRO tool is: (1) feasible for adoption in interdisciplinary primary health care practices and (2) usable from both the patient and provider perspectives. This usability pilot is part of a broader user-centered design development strategy. Methods A 4-week pilot study was conducted in which patients and providers used the ePRO tool to develop health-related goals, which patients then monitored using a mobile device. Patients and providers collaboratively set goals using the system during an initial visit and had at least 1 follow-up visit at the end of the pilot to discuss progress. Focus groups and interviews were conducted with patients and providers to capture usability and feasibility measures. Data from the ePRO system were extracted to provide information regarding tool usage. Results Six providers and 11 patients participated in the study; 3 patients dropped out mainly owing to health issues. The remaining 8 patients completed 210 monitoring protocols, equal to over 1300 questions, with patients often answering questions daily. Providers and patients

  17. Multifunctional Inverse Opal-Like TiO2 Electron Transport Layer for Efficient Hybrid Perovskite Solar Cells.

    Science.gov (United States)

    Chen, Xiao; Yang, Shuang; Zheng, Yi Chu; Chen, Ying; Hou, Yu; Yang, Xiao Hua; Yang, Hua Gui

    2015-09-01

    A novel multifunctional inverse opal-like TiO 2 electron transport layer (IOT-ETL) is designed to replace the traditional compact layer and mesoporous scaffold layer in perovskite solar cells (PSCs). Improved light harvesting efficiency and charge transporting performance in IOT-ETL based PSCs yield high power conversion efficiency of 13.11%.

  18. Ozone (Environmental Health Student Portal)

    Science.gov (United States)

    Skip Navigation National Library of Medicine Environmental Health Student Portal Connecting Middle School Students to Environmental Health Information Menu Home Air Pollution Air Pollution Home Indoor Air Pollution Outdoor ...

  19. Pesticides (Environmental Health Student Portal)

    Science.gov (United States)

    Skip Navigation National Library of Medicine Environmental Health Student Portal Connecting Middle School Students to Environmental Health Information Menu Home Air Pollution Air Pollution Home Indoor Air Pollution Outdoor ...

  20. Radioisotopic evaluation of portal circulation

    International Nuclear Information System (INIS)

    Maliska, C.; Rosenthal, D.

    1986-01-01

    The use of a radio-tracer of portal circulation through the intestine, should prevent cruel punctures in the portal-vein or spleen as it is usually the case with traditional methods in the study of portal-system. The absorption of I-131 and Tc-99m, previously cheked in rabbits presented similar results in dogs. The time of circulation between terminal large-intestine and the liver (t-RF) was determined by external counting at hepatic level by recording radioactivity variation-time. In healthy animals the t-RF was from 20to 60 seconds, with average time of 42 seconds. In 2 animals with partial binding of portal-vein the t-RF went up to 110 and 120 seconds. (Author) [pt

  1. Airbus’s Supplier Portal: changing a business paradigm

    NARCIS (Netherlands)

    E.M. van Raaij (Erik); J.C.M. van den Ende (Jan); D. Baumann (Dominic)

    2015-01-01

    textabstractWith procurement volume determining 75 to 80 per cent of costs, Airbus heavily depends on its 1,000 or more key suppliers. As a solution to the complexity of its supply chain, it introduced a portal to serve as an electronic marketplace for all interactions with its suppliers. Five years

  2. Users’ Awareness of Electronic Books is Limited. A review of: Levine‐Clark, Michael. “Electronic Book Usage: A Survey at the University of Denver.” portal: Libraries and the Academy 6.3 (Jul. 2006: 285‐99.

    Directory of Open Access Journals (Sweden)

    Gale G. Hannigan

    2007-06-01

    Full Text Available Objective – To determine if university library users are aware of electronic books,and how and why electronic books are used.Design – Survey.Setting – University of Denver.Subjects – Two thousand sixty‐seven graduate and undergraduate students, faculty, and staff.Methods – In Spring 2005, the University of Denver faculty, and graduate and undergraduate students were invited to participate in a survey about awareness and use of electronic books. A link to the survey was also posted on the library’s home pageand on the university’s Web portal. The 19‐question survey consisted of 11 questions to get feedback about electronic books in general, five questions focused on netLibrary,and the remaining were demographic questions. Eligibility to win one of two university bookstore gift certificates provided incentive to complete the survey.Main results – Surveys were completed by 2,067 respondents, including undergraduate students (30.1%, graduate students (39.1%,faculty (12.5%, and staff (11.8%. Results were reported by question, broken out by status (undergraduate students, graduate students, faculty and/or by discipline (Business, Humanities, Nontraditional, Professional, Sciences, Social Sciences, and presented in tables or in the text. In general, most respondents (59.1% were aware that the library provides access to electronic books. The library catalog and professors were the main ways respondents learned about electronic books. Approximately half (51.3% indicated they had used an electronic book. Of those who indicated that they used electronic books (1,061 respondents, most (72% had used electronic books more than once. The main reasons mentioned for choosing to use an electronic book included: no print version available, working from home makes getting to the library difficult, and searching text in an electronic book is easier. When asked about typical use of electronic books, most respondents indicated they read only apart

  3. A new method to measure and increase the detection efficiency of a microchannel plate for 100 keV electrons

    International Nuclear Information System (INIS)

    Tornow, R.P.

    1990-01-01

    A new method is described which permits measurement of efficiency of a microchannel plate (MCP) simply by tracing the output current pulse in the saturated mode. The dependence of the detection efficiency on the gain of the input stages of a detector is calculated and the result is applied to a MCP. Furthermore, an enhancement of the detection efficiency of a MCP is presented for 100 keV electrons up to more than 90% by means of the field-enhanced secondary electron emission. (author)

  4. Pyridine substituted spirofluorene derivative as an electron transport material for high efficiency in blue organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Soon Ok; Yook, Kyoung Soo; Lee, Jun Yeob, E-mail: leej17@dankook.ac.k

    2010-11-01

    The quantum efficiency of blue fluorescent organic light-emitting diodes was enhanced by 20% using a pyridine substituted spirofluorene-benzofluorene derivative as an electron transport material. 2',7'-Di(pyridin-3-yl)spiro[benzofluorene-7,9'-fluorene] (SPBP) was synthesized and it was used as the electron transport material to block the hole leakage from the emitting layer. The improvement of the quantum efficiency and power efficiency of the blue fluorescent organic light-emitting diodes using the SPBP was investigated.

  5. Quality control of portal imaging with PTW EPID QC PHANTOM registered

    International Nuclear Information System (INIS)

    Pesznyak, Csilla; Kiraly, Reka; Polgar, Istvan; Zarand, Pal; Mayer, Arpad; Fekete, Gabor; Mozes, Arpad; Kiss, Balazs

    2009-01-01

    Purpose: quality assurance (QA) and quality control (QC) of different electronic portal imaging devices (EPID) and portal images with the PTW EPID QC PHANTOM registered . Material and methods: characteristic properties of images of different file formats were measured on Siemens OptiVue500aSi registered , Siemens BeamView Plus registered , Elekta iView registered , and Varian PortalVision trademark and analyzed with the epidSoft registered 2.0 program in four radiation therapy centers. The portal images were taken with Kodak X-OMAT V registered and the Kodak Portal Localisation ReadyPack registered films and evaluated with the same program. Results: the optimal exposition both for EPIDs and portal films of different kind was determined. For double exposition, the 2+1 MU values can be recommended in the case of Siemens OptiVue500aSi registered , Elekta iView registered and Kodak Portal Localisation ReadyPack registered films, while for Siemens BeamView Plus registered , Varian PortalVision trademark and Kodak X-OMAT V registered film 7+7 MU is recommended. Conclusion: the PTW EPID QC PHANTOM registered can be used not only for amorphous silicon EPIDs but also for images taken with a video-based system or by using an ionization chamber matrix or for portal film. For analysis of QC tests, a standardized format (used at the acceptance test) should be applied, as the results are dependent on the file format used. (orig.)

  6. Realization of high efficiency in a plasma-assisted microwave source with two-dimensional electron motion

    International Nuclear Information System (INIS)

    Shkvarunets, A.G.; Carmel, Y.; Nusinovich, G.S.; Abu-elfadl, T.M.; Rodgers, J.; Antonsen, T.M. Jr.; Granatstein, V.; Goebel, D.M.

    2002-01-01

    Conventional microwave sources utilize a strong axial magnetic field to guide an electron beam through an interaction region. A plasma-assisted slow wave microwave oscillator (Pasotron) can operate without an external magnetic field because the presence of ions neutralizes the space charge in the beam, permits the self-pinch forces to provide beam propagation, and allows for the radial motion of electrons under the action of transverse fields of the wave. While the inherent efficiency of conventional microwave sources with 1D electron flow is limited to 15%-20%, it is shown in this work that both the calculated and measured inherent efficiency of devices with 2D electron flow can be higher than 50%. Both in situ diagnostics and analysis confirmed that the enhanced efficiency is due to the fact that rf forces dominate the beam dynamics

  7. Racial/ethnic variation in devices used to access patient portals.

    Science.gov (United States)

    Chang, Eva; Blondon, Katherine; Lyles, Courtney R; Jordan, Luesa; Ralston, James D

    2018-01-01

    We examined racial/ethnic variation in the devices used by patients to access medical records through an online patient portal. Retrospective, cross-sectional analysis. Using data from 318,700 adults enrolled in an integrated delivery system between December 2012 and November 2013, we examined: 1) online patient portal use that directly engages the electronic health record and 2) portal use over desktops/laptops only, mobile devices only, or both device types. The primary covariate was race/ethnicity (non-Hispanic white, black, Hispanic, and Asian). Other covariates included age, sex, primary language, and neighborhood-level income and education. Portal use and devices used were assessed with multiple and multinomial logistic models, respectively. From December 2012 to November 2013, 56% of enrollees used the patient portal. Of these portal users, 62% used desktops/laptops only, 6% used mobile devices only, and 32% used both desktops/laptops and mobile devices. Black, Hispanic, and Asian enrollees had significantly lower odds of portal use than whites. Black and Hispanic portal users also were significantly more likely to use mobile devices only (relative risk ratio, 1.73 and 1.44, respectively) and both device types (1.21 and 1.07, respectively) than desktops/laptops only compared with whites. Although racial/ethnic minority enrollees were less likely to access the online patient portal overall, a greater proportion of black and Hispanic users accessed the patient portal with mobile devices than did non-Hispanic white users. The rapid spread of mobile devices among racial/ethnic minorities may help reduce variation in online patient portal use. Mobile device use may represent an opportunity for healthcare organizations to further engage black and Hispanic enrollees in online patient portal use.

  8. The portal protein plays essential roles at different steps of the SPP1 DNA packaging process

    International Nuclear Information System (INIS)

    Isidro, Anabela; Henriques, Adriano O.; Tavares, Paulo

    2004-01-01

    A large number of viruses use a specialized portal for entry of DNA to the viral capsid and for its polarized exit at the beginning of infection. These families of viruses assemble an icosahedral procapsid containing a portal protein oligomer in one of its 12 vertices. The viral ATPase (terminase) interacts with the portal vertex to form a powerful molecular motor that translocates DNA to the procapsid interior against a steep concentration gradient. The portal protein is an essential component of this DNA packaging machine. Characterization of single amino acid substitutions in the portal protein gp6 of bacteriophage SPP1 that block DNA packaging identified sequential steps in the packaging mechanism that require its action. Gp6 is essential at early steps of DNA packaging and for DNA translocation to the capsid interior, it affects the efficiency of DNA packaging, it is a central component of the headful sensor that determines the size of the packaged DNA molecule, and is essential for closure of the portal pore by the head completion proteins to prevent exit of the DNA encapsidated. Functional regions of gp6 necessary at each step are identified within its primary structure. The similarity between the architecture of portal oligomers and between the DNA packaging strategies of viruses using portals strongly suggests that the portal protein plays the same roles in a large number of viruses

  9. Kinetics and efficiency of the hydrated electron-induced dehalogenation by the sulfite/UV process.

    Science.gov (United States)

    Li, Xuchun; Fang, Jingyun; Liu, Guifang; Zhang, Shujuan; Pan, Bingcai; Ma, Jun

    2014-10-01

    Hydrated electron (e(aq)(-)), which is listed among the most reactive reducing species, has great potential for removal and detoxification of recalcitrant contaminants. Here we provided quantitative insight into the availability and conversion of e(aq)(-) in a newly developed sulfite/UV process. Using monochloroacetic acid as a simple e(aq)(-)-probe, the e(aq)(-)-induced dehalogenation kinetics in synthetic and surface water was well predicted by the developed models. The models interpreted the complex roles of pH and S(IV), and also revealed the positive effects of UV intensity and temperature quantitatively. Impacts of humic acid, ferrous ion, carbonate/bicarbonate, and surface water matrix were also examined. Despite the retardation of dehalogenation by electron scavengers, the process was effective even in surface water. Efficiency of the process was discussed, and the optimization approaches were proposed. This study is believed to better understand the e(aq)(-)-induced dehalogenation by the sulfite/UV process in a quantitative manner, which is very important for its potential application in water treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Effect of electron-vibration interactions on the thermoelectric efficiency of molecular junctions.

    Science.gov (United States)

    Hsu, Bailey C; Chiang, Chi-Wei; Chen, Yu-Chang

    2012-07-11

    From first-principles approaches, we investigate the thermoelectric efficiency of a molecular junction where a benzene molecule is connected directly to the platinum electrodes. We calculate the thermoelectric figure of merit ZT in the presence of electron-vibration interactions with and without local heating under two scenarios: linear response and finite bias regimes. In the linear response regime, ZT saturates around the electrode temperature T(e) = 25 K in the elastic case, while in the inelastic case we observe a non-saturated and a much larger ZT beyond T(e) = 25 K attributed to the tail of the Fermi-Dirac distribution. In the finite bias regime, the inelastic effects reveal the signatures of the molecular vibrations in the low-temperature regime. The normal modes exhibiting structures in the inelastic profile are characterized by large components of atomic vibrations along the current density direction on top of each individual atom. In all cases, the inclusion of local heating leads to a higher wire temperature T(w) and thus magnifies further the influence of the electron-vibration interactions due to the increased number of local phonons.

  11. Portal vein thrombosis; risk factors, clinical presentation and treatment

    DEFF Research Database (Denmark)

    Sogaard, Kirstine K; Astrup, Lone B; Vilstrup, Hendrik

    2007-01-01

    and treatment of portal vein thrombosis in a single-centre. METHODS: Sixty-seven patients were identified in the electronic records from 1992 to 2005. All data were obtained from the patient records. RESULTS: One or more risk factors (e.g. prothrombotic disorder or abdominal inflammation) were present in 87......BACKGROUND: Portal vein thrombosis (PVT) is increasingly frequently being diagnosed, but systematic descriptions of the natural history and clinical handling of the condition are sparse. The aim of this retrospective study was to describe risk factors, clinical presentation, complications...

  12. Electronic health record impact on productivity and efficiency in an academic pediatric ophthalmology practice.

    Science.gov (United States)

    Redd, Travis K; Read-Brown, Sarah; Choi, Dongseok; Yackel, Thomas R; Tu, Daniel C; Chiang, Michael F

    2014-12-01

    To measure the effect of electronic health record (EHR) implementation on productivity and efficiency in the pediatric ophthalmology division at an academic medical center. Four established providers were selected from the pediatric ophthalmology division at the Oregon Health & Science University Casey Eye Institute. Clinical volume was compared before and after EHR implementation for each provider. Time elapsed from chart open to completion (OTC time) and the proportion of charts completed during business hours were monitored for 3 years following implementation. Overall there was an 11% decrease in clinical volume following EHR implementation, which was not statistically significant (P = 0.18). The mean OTC time ranged from 5.5 to 28.3 hours among providers in this study, and trends over time were variable among the four providers. Forty-four percent of all charts were closed outside normal business hours (30% on weekdays, 14% on weekends). EHR implementation was associated with a negative impact on productivity and efficiency in our pediatric ophthalmology division. Copyright © 2014 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  13. Interfacial engineering of electron transport layer using Caesium Iodide for efficient and stable organic solar cells

    Science.gov (United States)

    Upama, Mushfika Baishakhi; Elumalai, Naveen Kumar; Mahmud, Md Arafat; Wright, Matthew; Wang, Dian; Xu, Cheng; Haque, Faiazul; Chan, Kah Howe; Uddin, Ashraf

    2017-09-01

    Polymer solar cells (PSCs) have gained immense research interest in the recent years predominantly due to low-cost, solution process-ability, and facile device fabrication. However, achieving high stability without compromising the power conversion efficiency (PCE) serves to be an important trade-off for commercialization. In line with this, we demonstrate the significance of incorporating a CsI/ZnO bilayer as electron transport layer (ETL) in the bulk heterojunction PSCs employing low band gap polymer (PTB7) and fullerene (PC71BM) as the photo-active layer. The devices with CsI/ZnO interlayer exhibited substantial enhancement of 800% and 12% in PCE when compared to the devices with pristine CsI and pristine ZnO as ETL, respectively. Furthermore, the UV and UV-ozone induced degradation studies revealed that the devices incorporating CsI/ZnO bilayer possess excellent decomposition stability (∼23% higher) over the devices with pristine ZnO counterparts. The incorporation of CsI between ITO and ZnO was found to favorably modify the energy-level alignment at the interface, contributing to the charge collection efficiency as well as protecting the adjacent light absorbing polymer layers from degradation. The mechanism behind the improvement in PCE and stability is analyzed using the electrochemical impedance spectroscopy and dark I-V characteristics.

  14. The approach to engineering tasks composition on knowledge portals

    Science.gov (United States)

    Novogrudska, Rina; Globa, Larysa; Schill, Alexsander; Romaniuk, Ryszard; Wójcik, Waldemar; Karnakova, Gaini; Kalizhanova, Aliya

    2017-08-01

    The paper presents an approach to engineering tasks composition on engineering knowledge portals. The specific features of engineering tasks are highlighted, their analysis makes the basis for partial engineering tasks integration. The formal algebraic system for engineering tasks composition is proposed, allowing to set the context-independent formal structures for engineering tasks elements' description. The method of engineering tasks composition is developed that allows to integrate partial calculation tasks into general calculation tasks on engineering portals, performed on user request demand. The real world scenario «Calculation of the strength for the power components of magnetic systems» is represented, approving the applicability and efficiency of proposed approach.

  15. Clinical Implementation of a Model-Based In Vivo Dose Verification System for Stereotactic Body Radiation Therapy–Volumetric Modulated Arc Therapy Treatments Using the Electronic Portal Imaging Device

    Energy Technology Data Exchange (ETDEWEB)

    McCowan, Peter M., E-mail: pmccowan@cancercare.mb.ca [Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba (Canada); Asuni, Ganiyu [Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba (Canada); Van Uytven, Eric [Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba (Canada); VanBeek, Timothy [Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba (Canada); McCurdy, Boyd M.C. [Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba (Canada); Department of Radiology, University of Manitoba, Winnipeg, Manitoba (Canada); Loewen, Shaun K. [Department of Oncology, University of Calgary, Calgary, Alberta (Canada); Ahmed, Naseer; Bashir, Bashir; Butler, James B.; Chowdhury, Amitava; Dubey, Arbind; Leylek, Ahmet; Nashed, Maged [CancerCare Manitoba, Winnipeg, Manitoba (Canada)

    2017-04-01

    Purpose: To report findings from an in vivo dosimetry program implemented for all stereotactic body radiation therapy patients over a 31-month period and discuss the value and challenges of utilizing in vivo electronic portal imaging device (EPID) dosimetry clinically. Methods and Materials: From December 2013 to July 2016, 117 stereotactic body radiation therapy–volumetric modulated arc therapy patients (100 lung, 15 spine, and 2 liver) underwent 602 EPID-based in vivo dose verification events. A developed model-based dose reconstruction algorithm calculates the 3-dimensional dose distribution to the patient by back-projecting the primary fluence measured by the EPID during treatment. The EPID frame-averaging was optimized in June 2015. For each treatment, a 3%/3-mm γ comparison between our EPID-derived dose and the Eclipse AcurosXB–predicted dose to the planning target volume (PTV) and the ≥20% isodose volume were performed. Alert levels were defined as γ pass rates <85% (lung and liver) and <80% (spine). Investigations were carried out for all fractions exceeding the alert level and were classified as follows: EPID-related, algorithmic, patient setup, anatomic change, or unknown/unidentified errors. Results: The percentages of fractions exceeding the alert levels were 22.6% for lung before frame-average optimization and 8.0% for lung, 20.0% for spine, and 10.0% for liver after frame-average optimization. Overall, mean (± standard deviation) planning target volume γ pass rates were 90.7% ± 9.2%, 87.0% ± 9.3%, and 91.2% ± 3.4% for the lung, spine, and liver patients, respectively. Conclusions: Results from the clinical implementation of our model-based in vivo dose verification method using on-treatment EPID images is reported. The method is demonstrated to be valuable for routine clinical use for verifying delivered dose as well as for detecting errors.

  16. High-efficiency detector of secondary and backscattered electrons for low-dose imaging in the ESEM.

    Science.gov (United States)

    Neděla, Vilém; Tihlaříková, Eva; Runštuk, Jiří; Hudec, Jiří

    2018-01-01

    A new Combined System for high-efficiency detection of Secondary and Backscattered Electrons (CSSBE) in the ESEM consists of three detectors: an ionisation SE detector, an improved scintillation BSE detector, and a new Ionisation Secondary Electron Detector with an electrostatic Separator (ISEDS). The ISEDS optimizes conditions for electron-gas ionisation phenomena in the ESEM to achieve a strongly amplified signal from the secondary electrons with a minimal contribution from backscattered and beam electrons. For this purpose, it is originally equipped with an electrostatic separator, which focuses signal electrons towards a detection electrode and controls the concentration of positive ions above the sample. The working principle of the ISEDS is explained by simulations of signal electron trajectories in gas using the EOD program with our Monte Carlo module. The ability to detect the signal electrons in a selected range of energies is described with Geant4 Monte Carlo simulations of electron-solid interactions and proven by experimental results. High-efficiency detection of the ISEDS is demonstrated by imaging a low atomic number sample under a reduced beam energy of 5 keV, very low beam currents of up to 0.2 pA, and gas pressure of hundreds of Pa. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Mesoscopic Oxide Double Layer as Electron Specific Contact for Highly Efficient and UV Stable Perovskite Photovoltaics.

    Science.gov (United States)

    Tavakoli, Mohammad Mahdi; Giordano, Fabrizio; Zakeeruddin, Shaik Mohammed; Grätzel, Michael

    2018-04-11

    The solar to electric power conversion efficiency (PCE) of perovskite solar cells (PSCs) has recently reached 22.7%, exceeding that of competing thin film photovoltaics and the market leader polycrystalline silicon. Further augmentation of the PCE toward the Shockley-Queisser limit of 33.5% warrants suppression of radiationless carrier recombination by judicious engineering of the interface between the light harvesting perovskite and the charge carrier extraction layers. Here, we introduce a mesoscopic oxide double layer as electron selective contact consisting of a scaffold of TiO 2 nanoparticles covered by a thin film of SnO 2 , either in amorphous (a-SnO 2 ), crystalline (c-SnO 2 ), or nanocrystalline (quantum dot) form (SnO 2 -NC). We find that the band gap of a-SnO 2 is larger than that of the crystalline (tetragonal) polymorph leading to a corresponding lift in its conduction band edge energy which aligns it perfectly with the conduction band edge of both the triple cation perovskite and the TiO 2 scaffold. This enables very fast electron extraction from the light perovskite, suppressing the notorious hysteresis in the current-voltage ( J-V) curves and retarding nonradiative charge carrier recombination. As a result, we gain a remarkable 170 mV in open circuit photovoltage ( V oc ) by replacing the crystalline SnO 2 by an amorphous phase. Because of the quantum size effect, the band gap of our SnO 2 -NC particles is larger than that of bulk SnO 2 causing their conduction band edge to shift also to a higher energy thereby increasing the V oc . However, for SnO 2 -NC there remains a barrier for electron injection into the TiO 2 scaffold decreasing the fill factor of the device and lowering the PCE. Introducing the a-SnO 2 coated mp-TiO 2 scaffold as electron extraction layer not only increases the V oc and PEC of the solar cells but also render them resistant to UV light which forebodes well for outdoor deployment of these new PSC architectures.

  18. Portal pressure correlated to visceral circulation times

    Energy Technology Data Exchange (ETDEWEB)

    Friman, L [Serafimerlasarettet, Stockholm (Sweden)

    1979-01-01

    Visceral angiography was performed in 7 patients with normal portal pressure and in 10 with portal hypertension. Circulation times, size of vessels and portal pressure were determined. At celiac angiography, a direct correlation was found between time for maximum filling of portal vein and portal pressure, provided no vascular abnormalities existed. At superior mesenteric angiography such a correlation was not found; loss of flow by shunts in portal hypertension being one explanation. Portocaval shunts are common in the celiac system, but uncommon in the superior mesenteric system.

  19. Portal pressure correlated to visceral circulation times

    International Nuclear Information System (INIS)

    Friman, L.

    1979-01-01

    Visceral angiography was performed in 7 patients with normal portal pressure and in 10 with portal hypertension. Circulation times, size of vessels and portal pressure were determined. At celiac angiography, a direct correlation was found between time for maximum filling of portal vein and portal pressure, provided no vascular abnormalities existed. At superior mesenteric angiography such a correlation was not found; loss of flow by shunts in portal hypertension being one explanation. Portocaval shunts are common in the celiac system, but uncommon in the superior mesenteric system. (Auth.)

  20. Galaxy Portal: interacting with the galaxy platform through mobile devices.

    Science.gov (United States)

    Børnich, Claus; Grytten, Ivar; Hovig, Eivind; Paulsen, Jonas; Čech, Martin; Sandve, Geir Kjetil

    2016-06-01

    : We present Galaxy Portal app, an open source interface to the Galaxy system through smart phones and tablets. The Galaxy Portal provides convenient and efficient monitoring of job completion, as well as opportunities for inspection of results and execution history. In addition to being useful to the Galaxy community, we believe that the app also exemplifies a useful way of exploiting mobile interfaces for research/high-performance computing resources in general. The source is freely available under a GPL license on GitHub, along with user documentation and pre-compiled binaries and instructions for several platforms: https://github.com/Tarostar/QMLGalaxyPortal It is available for iOS version 7 (and newer) through the Apple App Store, and for Android through Google Play for version 4.1 (API 16) or newer. geirksa@ifi.uio.no. © The Author 2016. Published by Oxford University Press.

  1. VERTICAL PROJECTION EFFICIENCY OF PIVOT POINTS USING ELECTRONIC TACHEOMETER DURING CONSTRUCTION OF BUILDINGS AND STRUCTURES

    Directory of Open Access Journals (Sweden)

    M. S. Nesterenok

    2014-01-01

    transfer to mounting horizon using inclined projection in the point with plane coordinates which differ from initial point coordinates within the limits of apparent standard graph area. Such point can be indicated with the help of dot L.E.D. located on standard graph. Its spatial polar and rectangular coordinates on horizontal plane are determined by angular measurements with readings along both bearing circles of the electronic tacheometer and projection height.Production practice and executed experiments have permitted to make the following conclusions: a modern electronic tacheometer equipped with ocular attachment for telescope sighting in the zenith direction can be and must be efficiently applied for vertical point projection of internal geodetic base of a constructed building or a structure. The mentioned device ensures transfer of geodetic base points to mounting horizon not only vertically but also with inclination of a projected beam within sequential visibility of openings in intermediate floors that allows to adapt projection trajectory to specific conditions of its passing.

  2. Portal monitor incorporating smart probes

    International Nuclear Information System (INIS)

    Bartos, D.; Constantin, F.; Guta, T.

    2003-01-01

    Portal monitors are intended for detection of radioactive and special nuclear materials in vehicles, pedestrians, luggage, as well as for prevention of illegal traffic of radioactive sources. Monitors provide audio and visual alarms when radioactive and/or special nuclear materials are detected. They can be recommended to officers of customs, border guard and emergency services, civil defense, fire brigades, police and military departments or nuclear research or energetic facilities. The portal monitor developed by us consists in a portal frame, which sustains five intelligent probes having long plastic scintillator (0.5 liters each). The probes communicate, by serial transmission, with a Central Unit constructed on the basis of the 80552 microcontroller. This one manages the handshake, calculates the background, establishes the measuring time, starts and stops each measurement and makes all the other decisions. Sound signals and an infrared sensor monitor the passing through the portal and the measuring procedure. For each measurement the result is displayed on a LCD device contaminated/uncontaminated; for the contaminated case a loud and long sound signal is also issued. An RS 232 serial interface is provided in order to further developments or custom made devices. As a result, the portal monitor detects 1 μ Ci 137 Cs, spread all over a human body, in a 20 μR/h gamma background for a measuring time of 1.5 or 10 seconds giving a 99% confidence factor. (authors)

  3. CT findings of portal vein aneurysm

    International Nuclear Information System (INIS)

    Yang, Dal Mo; Chang, Mi Son; Yoon, Myung Hwan; Kim, Hak Soo; Kim, Hyung Sik; Chung, Hyo Sun; Chung, Jin Woo

    1999-01-01

    To describe the CT findings of portal vein aneurysm in eight patients. All patients included in this study (two men and six women) underwent CT examinations between October 1996 and June1998. Of these eight, three were suffering from hepatic disease and portal hypertension. We determined the location, shape, size, and characteristics of the lesions, and the presence or absence of portal vein anomaly. Seven patients had intrahepatic portal vein aneurysm (at the umbilical portion of the left portal vein in five patients, between the transverse and umbilical portion of the left portal vein in one, and at the bifurcation of the anterior and posterior branch of the right portal vein in one), while extrahepatic portal vein aneurysm, at the confluence of the superior mesenteric and splenic vein was found in only one. Lesions were cyst-shaped in seven cases and saccular in one, and showed well-circumscribed, markedly enhanced mass, which communicated with the portal vein and/or gives off major branches. Portal vein anomaly, in which the right anterior segmental portal vein originated from the umbilical portion of the left portal vein, was seen in three patients. In all three, intrahepatic portal vein aneurysm was present at the umbilical portion of the left portal vein, and in one, the umbilical protion of the left portal vein was located to the right of the Cantlic line. CT examination can help reveal portal vein aneurysm by detecting a well-circumscribed, markedly enhanced mass which communicates with the portal vein and/or gives off major branches

  4. Efficient composite fabrication using electron-beam rapidly cured polymers engineered for several manufacturing processes

    International Nuclear Information System (INIS)

    Walton, T.C.; Crivello, J.V.

    1995-01-01

    Low cost, efficiently processed ultra high specific strength and stiffness graphite fiber reinforced polymeric composite materials are of great interest to commercial transportation, construction and aerospace industries for use in various components with enhanced degrees of weight reduction, corrosion/erosion resistance and fatigue resistance. 10 MeV Electron Beam cure processing has been found to increase the cure rate by an order of magnitude over thermally cured systems yet provide less molded in stresses and high T g s. However, a limited range of resins are available which are easily processed with low shrinkage and with performance properties equal or exceeding those of state of the art toughened epoxies and BMI's. The technology, introduced by an academia-industry partnership sparked by Langley Research Center utilizes a cost effective, rapid curing polymeric composite processing technique which effectively reduces the need for expensive tooling and energy inefficient autoclave processing and can cure the laminate in seconds (compared to hours for thermal curing) in ambient or sub-ambient conditions. The process is based on electron beam (E-Beam) curing of a new series of (65 to 1,000,000 cPs.) specially formulated resins that have been shown to exhibit excellent mechanical and physical properties once cured. Fabrication processes utilizing these specially formulated and newly commercialized resins, (e.g. including Vacuum Assist Resin Transfer molding (VARTM), vacuum bag prepreg layup, pultrusion and filament winding grades) are engineered to cure with low shrinkage, provide excellent mechanical properties, be processed solventless (environmentally friendly) and are inherently non toxic

  5. Reliability in endoscopic diagnosis of portal hypertensive gastropathy

    Science.gov (United States)

    de Macedo, George Fred Soares; Ferreira, Fabio Gonçalves; Ribeiro, Maurício Alves; Szutan, Luiz Arnaldo; Assef, Mauricio Saab; Rossini, Lucio Giovanni Battista

    2013-01-01

    AIM: To analyze reliability among endoscopists in diagnosing portal hypertensive gastropathy (PHG) and to determine which criteria from the most utilized classifications are the most suitable. METHODS: From January to July 2009, in an academic quaternary referral center at Santa Casa of São Paulo Endoscopy Service, Brazil, we performed this single-center prospective study. In this period, we included 100 patients, including 50 sequential patients who had portal hypertension of various etiologies; who were previously diagnosed based on clinical, laboratory and imaging exams; and who presented with esophageal varices. In addition, our study included 50 sequential patients who had dyspeptic symptoms and were referred for upper digestive endoscopy without portal hypertension. All subjects underwent upper digestive endoscopy, and the images of the exam were digitally recorded. Five endoscopists with more than 15 years of experience answered an electronic questionnaire, which included endoscopic criteria from the 3 most commonly used Portal Hypertensive Gastropathy classifications (McCormack, NIEC and Baveno) and the presence of elevated or flat antral erosive gastritis. All five endoscopists were blinded to the patients’ clinical information, and all images of varices were deliberately excluded for the analysis. RESULTS: The three most common etiologies of portal hypertension were schistosomiasis (36%), alcoholic cirrhosis (20%) and viral cirrhosis (14%). Of the 50 patients with portal hypertension, 84% were Child A, 12% were Child B, 4% were Child C, 64% exhibited previous variceal bleeding and 66% were previously endoscopic treated. The endoscopic parameters, presence or absence of mosaic-like pattern, red point lesions and cherry-red spots were associated with high inter-observer reliability and high specificity for diagnosing Portal Hypertensive Gastropathy. Sensitivity, specificity and reliability for the diagnosis of PHG (%) were as follows: mosaic-like pattern

  6. Towards efficient ab initio calculations of electron scattering by polyatomic molecules: II. Efficient evaluation of exchange integrals

    Czech Academy of Sciences Publication Activity Database

    Čársky, Petr

    2010-01-01

    Roč. 43, č. 17 (2010), s. 175204 ISSN 0953-4075 R&D Projects: GA MŠk OC09079; GA MŠk(CZ) OC10046; GA ČR GA202/08/0631 Institutional research plan: CEZ:AV0Z40400503 Keywords : ab initio calculations * electron scattering * polyatomic molecules Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.902, year: 2010

  7. Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton-proton collision data

    CERN Document Server

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Hartjes, Fred; Harvey, Alex; Hasegawa, Satoshi; Hasegawa, Yoji; Hasib, A; Hassani, Samira; Haug, Sigve; Hauschild, Michael; Hauser, Reiner; Havranek, Miroslav; Hawkes, Christopher; Hawkings, Richard John; Hawkins, Anthony David; Hayashi, Takayasu; Hayden, Daniel; Hays, Chris; Hayward, Helen; Haywood, Stephen; Head, Simon; Heck, Tobias; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heim, Timon; Heinemann, Beate; Heinrich, Lukas; Heisterkamp, Simon; Hejbal, Jiri; Helary, Louis; Heller, Claudio; Heller, Matthieu; Hellman, Sten; Hellmich, Dennis; Helsens, Clement; Henderson, James; Henderson, Robert; Hengler, Christopher; Henrichs, Anna; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Hensel, Carsten; Herbert, Geoffrey Henry; Hernández Jiménez, Yesenia; Herrberg-Schubert, Ruth; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Hickling, Robert; Higón-Rodriguez, Emilio; Hill, John; Hiller, Karl Heinz; Hillert, Sonja; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hirose, Minoru; Hirschbuehl, Dominic; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoffman, Julia; Hoffmann, Dirk; Hofmann, Julia Isabell; Hohlfeld, Marc; Holmes, Tova Ray; Hong, Tae Min; Hooft van Huysduynen, Loek; Hostachy, Jean-Yves; Hou, Suen; Hoummada, Abdeslam; Howard, Jacob; Howarth, James; Hrabovsky, Miroslav; Hristova, Ivana; Hrivnac, Julius; Hryn'ova, Tetiana; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Hu, Diedi; Hu, Xueye; Huang, Yanping; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Huhtinen, Mika; Hülsing, Tobias Alexander; Hurwitz, Martina; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibragimov, Iskander; Iconomidou-Fayard, Lydia; Idarraga, John; Ideal, Emma; Iengo, Paolo; Igonkina, Olga; Iizawa, Tomoya; Ikegami, Yoichi; Ikematsu, Katsumasa; Ikeno, Masahiro; Iliadis, Dimitrios; Ilic, Nikolina; Inamaru, Yuki; Ince, Tayfun; Ioannou, Pavlos; Iodice, Mauro; Iordanidou, Kalliopi; Ippolito, Valerio; Irles Quiles, Adrian; Isaksson, Charlie; Ishino, Masaya; Ishitsuka, Masaki; Ishmukhametov, Renat; Issever, Cigdem; Istin, Serhat; Iturbe Ponce, Julia Mariana; Ivashin, Anton; Iwanski, Wieslaw; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jackson, Brett; Jackson, John; Jackson, Matthew; Jackson, Paul; Jaekel, Martin; Jain, Vivek; Jakobs, Karl; Jakobsen, Sune; Jakoubek, Tomas; Jakubek, Jan; Jamin, David Olivier; Jana, Dilip; Jansen, Eric; Jansen, Hendrik; Janssen, Jens; Janus, Michel; Jarlskog, Göran; Javůrek, Tomáš; Jeanty, Laura; Jeng, Geng-yuan; Jennens, David; Jenni, Peter; Jentzsch, Jennifer; Jeske, Carl; Jézéquel, Stéphane; Ji, Haoshuang; Ji, Weina; Jia, Jiangyong; Jiang, Yi; Jimenez Belenguer, Marcos; Jin, Shan; Jinaru, Adam; Jinnouchi, Osamu; Joergensen, Morten Dam; Johansson, Erik; Johansson, Per; Johns, Kenneth; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Tim; Jongmanns, Jan; Jorge, Pedro; Joshi, Kiran Daniel; Jovicevic, Jelena; Ju, Xiangyang; Jung, Christian; Jungst, Ralph Markus; Jussel, Patrick; Juste Rozas, Aurelio; Kaci, Mohammed; Kaczmarska, Anna; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kajomovitz, Enrique; Kama, Sami; Kanaya, Naoko; Kaneda, Michiru; Kaneti, Steven; Kanno, Takayuki; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kapliy, Anton; Kar, Deepak; Karakostas, Konstantinos; Karastathis, Nikolaos; Karnevskiy, Mikhail; Karpov, Sergey; Karthik, Krishnaiyengar; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kashif, Lashkar; Kasieczka, Gregor; Kass, Richard; Kastanas, Alex; Kataoka, Yousuke; Katre, Akshay; Katzy, Judith; Kaushik, Venkatesh; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kazama, Shingo; Kazanin, Vassili; Kazarinov, Makhail; Keeler, Richard; Keener, Paul; Kehoe, Robert; Keil, Markus; Keller, John; Keoshkerian, Houry; Kepka, Oldrich; Kerševan, Borut Paul; Kersten, Susanne; Kessoku, Kohei; Keung, Justin; Khalil-zada, Farkhad; Khandanyan, Hovhannes; Khanov, Alexander; Khodinov, Alexander; Khomich, Andrei; Khoo, Teng Jian; Khoriauli, Gia; Khoroshilov, Andrey; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kim, Hee Yeun; Kim, Hyeon Jin; Kim, Shinhong; Kimura, Naoki; Kind, Oliver; King, Barry; King, Matthew; King, Robert Steven Beaufoy; King, Samuel Burton; Kirk, Julie; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kiss, Florian; Kitamura, Takumi; Kittelmann, Thomas; Kiuchi, Kenji; Kladiva, Eduard; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klinger, Joel Alexander; Klinkby, Esben; Klioutchnikova, Tatiana; Klok, Peter; Kluge, Eike-Erik; Kluit, Peter; Kluth, Stefan; Kneringer, Emmerich; Knoops, Edith; Knue, Andrea; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Koevesarki, Peter; Koffas, Thomas; Koffeman, Els; Kogan, Lucy Anne; Kohlmann, Simon; Kohout, Zdenek; Kohriki, Takashi; Koi, Tatsumi; Kolanoski, Hermann; Koletsou, Iro; Koll, James; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Köneke, Karsten; König, Adriaan; König, Sebastian; Kono, Takanori; Konoplich, Rostislav; Konstantinidis, Nikolaos; Kopeliansky, Revital; Koperny, Stefan; Köpke, Lutz; Kopp, Anna Katharina; Korcyl, Krzysztof; Kordas, Kostantinos; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Korotkov, Vladislav; Kortner, Oliver; Kortner, Sandra; Kostyukhin, Vadim; Kotov, Sergey; Kotov, Vladislav; Kotwal, Ashutosh; Kourkoumelis, Christine; Kouskoura, Vasiliki; Koutsman, Alex; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozanecki, Witold; Kozhin, Anatoly; Kral, Vlastimil; Kramarenko, Viktor; Kramberger, Gregor; Krasnopevtsev, Dimitriy; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kraus, Jana; Kravchenko, Anton; Kreiss, Sven; Kretz, Moritz; Kretzschmar, Jan; Kreutzfeldt, Kristof; Krieger, Peter; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Kruker, Tobias; Krumnack, Nils; Krumshteyn, Zinovii; Kruse, Amanda; Kruse, Mark; Kruskal, Michael; Kubota, Takashi; Kuday, Sinan; Kuehn, Susanne; Kugel, Andreas; Kuhl, Andrew; Kuhl, Thorsten; Kukhtin, Victor; Kulchitsky, Yuri; Kuleshov, Sergey; Kuna, Marine; Kunkle, Joshua; Kupco, Alexander; Kurashige, Hisaya; Kurochkin, Yurii; Kurumida, Rie; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; La Rosa, Alessandro; La Rotonda, Laura; Labarga, Luis; Lacasta, Carlos; Lacava, Francesco; Lacey, James; Lacker, Heiko; Lacour, Didier; Lacuesta, Vicente Ramón; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Laier, Heiko; Lambourne, Luke; Lammers, Sabine; Lampen, Caleb; Lampl, Walter; Lançon, Eric; Landgraf, Ulrich; Landon, Murrough; Lang, Valerie Susanne; Lange, Clemens; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Lassnig, Mario; Laurelli, Paolo; Lavorini, Vincenzo; Lavrijsen, Wim; Law, Alexander; Laycock, Paul; Le, Bao Tran; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Menedeu, Eve; LeCompte, Thomas; Ledroit-Guillon, Fabienne Agnes Marie; Lee, Claire Alexandra; Lee, Hurng-Chun; Lee, Jason; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Guillaume; Lefebvre, Michel; Legger, Federica; Leggett, Charles; Lehan, Allan; Lehmacher, Marc; Lehmann Miotto, Giovanna; Lei, Xiaowen; Leister, Andrew Gerard; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Lemmer, Boris; Leney, Katharine; Lenz, Tatjana; Lenzen, Georg; Lenzi, Bruno; Leone, Robert; Leonhardt, Kathrin; Leontsinis, Stefanos; Leroy, Claude; Lester, Christopher; Lester, Christopher Michael; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Levy, Mark; Lewis, Adrian; Lewis, George; Leyko, Agnieszka; Leyton, Michael; Li, Bing; Li, Bo; Li, Haifeng; Li, Ho Ling; Li, Shu; Li, Xuefei; Li, Yichen; Liang, Zhijun; Liao, Hongbo; Liberti, Barbara; Lichard, Peter; Lie, Ki; Liebal, Jessica; Liebig, Wolfgang; Limbach, Christian; Limosani, Antonio; Limper, Maaike; Lin, Simon; Linde, Frank; Lindquist, Brian Edward; Linnemann, James; Lipeles, Elliot; Lipniacka, Anna; Lisovyi, Mykhailo; Liss, Tony; Lissauer, David; Lister, Alison; Litke, Alan; Liu, Bo; Liu, Dong; Liu, Jianbei; Liu, Kun; Liu, Lulu; Liu, Miaoyuan; Liu, Minghui; Liu, Yanwen; Livan, Michele; Livermore, Sarah; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lo Sterzo, Francesco; Lobodzinska, Ewelina; Loch, Peter; Lockman, William; Loddenkoetter, Thomas; Loebinger, Fred; Loevschall-Jensen, Ask Emil; Loginov, Andrey; Loh, Chang Wei; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Lombardo, Vincenzo Paolo; Long, Jonathan; Long, Robin Eamonn; Lopes, Lourenco; Lopez Mateos, David; Lopez Paredes, Brais; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Loscutoff, Peter; Losty, Michael; Lou, XinChou; Lounis, Abdenour; Love, Jeremy; Love, Peter; Lowe, Andrew; Lu, Feng; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Luehring, Frederick; Lukas, Wolfgang; Luminari, Lamberto; Lundberg, Olof; Lund-Jensen, Bengt; Lungwitz, Matthias; Lynn, David; Lysak, Roman; Lytken, Else; Ma, Hong; Ma, Lian Liang; Maccarrone, Giovanni; Macchiolo, Anna; Maček, Boštjan; Machado Miguens, Joana; Macina, Daniela; Madaffari, Daniele; Madar, Romain; Maddocks, Harvey Jonathan; Mader, Wolfgang; Madsen, Alexander; Maeno, Mayuko; Maeno, Tadashi; Magradze, Erekle; Mahboubi, Kambiz; Mahlstedt, Joern; Mahmoud, Sara; Maiani, Camilla; Maidantchik, Carmen; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Mal, Prolay; Malaescu, Bogdan; Malecki, Pawel; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Caitlin; Maltezos, Stavros; Malyshev, Vladimir; Malyukov, Sergei; Mamuzic, Judita; Mandelli, Beatrice; Mandelli, Luciano; Mandić, Igor; Mandrysch, Rocco; Maneira, José; Manfredini, Alessandro; Manhaes de Andrade Filho, Luciano; Manjarres Ramos, Joany Andreina; Mann, Alexander; Manning, Peter; Manousakis-Katsikakis, Arkadios; Mansoulie, Bruno; Mantifel, Rodger; Mapelli, Livio; March, Luis; Marchand, Jean-Francois; Marchese, Fabrizio; Marchiori, Giovanni; Marcisovsky, Michal; Marino, Christopher; Marques, Carlos; Marroquim, Fernando; Marsden, Stephen Philip; Marshall, Zach; Marti, Lukas Fritz; Marti-Garcia, Salvador; Martin, Brian; Martin, Brian Thomas; Martin, Jean-Pierre; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martinez, Homero; Martinez, Mario; Martin-Haugh, Stewart; Martyniuk, Alex; Marx, Marilyn; Marzano, Francesco; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massol, Nicolas; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Matricon, Pierre; Matsunaga, Hiroyuki; Matsushita, Takashi; Mättig, Peter; Mättig, Stefan; Mattmann, Johannes; Maurer, Julien; Maxfield, Stephen; Maximov, Dmitriy; Mazini, Rachid; Mazzaferro, Luca; Mc Goldrick, Garrin; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McCubbin, Norman; McFarlane, Kenneth; Mcfayden, Josh; Mchedlidze, Gvantsa; Mclaughlan, Tom; McMahon, Steve; McPherson, Robert; Meade, Andrew; Mechnich, Joerg; Medinnis, Michael; Meehan, Samuel; Meera-Lebbai, Razzak; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meineck, Christian; Meirose, Bernhard; Melachrinos, Constantinos; Mellado Garcia, Bruce Rafael; Meloni, Federico; Mendoza Navas, Luis; Mengarelli, Alberto; Menke, Sven; Meoni, Evelin; Mercurio, Kevin Michael; Mergelmeyer, Sebastian; Meric, Nicolas; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Merritt, Hayes; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Middleton, Robin; Migas, Sylwia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Miller, David; Mills, Corrinne; Milov, Alexander; Milstead, David; Milstein, Dmitry; Minaenko, Andrey; Miñano Moya, Mercedes; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Ming, Yao; Mir, Lluisa-Maria; Mirabelli, Giovanni; Mitani, Takashi; Mitrevski, Jovan; Mitsou, Vasiliki A; Mitsui, Shingo; Miucci, Antonio; Miyagawa, Paul; Mjörnmark, Jan-Ulf; Moa, Torbjoern; Mochizuki, Kazuya; Moeller, Victoria; Mohapatra, Soumya; Mohr, Wolfgang; Molander, Simon; Moles-Valls, Regina; Mönig, Klaus; Monini, Caterina; Monk, James; Monnier, Emmanuel; Montejo Berlingen, Javier; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Mora Herrera, Clemencia; Moraes, Arthur; Morange, Nicolas; Morel, Julien; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Morgenstern, Marcus; Morii, Masahiro; Moritz, Sebastian; Morley, Anthony Keith; Mornacchi, Giuseppe; Morris, John; Morvaj, Ljiljana; Moser, Hans-Guenther; Mosidze, Maia; Moss, Josh; Mount, Richard; Mountricha, Eleni; Mouraviev, Sergei; Moyse, Edward; Muanza, Steve; Mudd, Richard; Mueller, Felix; Mueller, James; Mueller, Klemens; Mueller, Thibaut; Mueller, Timo; Muenstermann, Daniel; Munwes, Yonathan; Murillo Quijada, Javier Alberto; Murray, Bill; Musto, Elisa; Myagkov, Alexey; Myska, Miroslav; Nackenhorst, Olaf; Nadal, Jordi; Nagai, Koichi; Nagai, Ryo; Nagai, Yoshikazu; Nagano, Kunihiro; Nagarkar, Advait; Nagasaka, Yasushi; Nagel, Martin; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Namasivayam, Harisankar; Nanava, Gizo; Narayan, Rohin; Nattermann, Till; Naumann, Thomas; Navarro, Gabriela; Nayyar, Ruchika; Neal, Homer; Nechaeva, Polina; Neep, Thomas James; Negri, Andrea; Negri, Guido; Negrini, Matteo; Nektarijevic, Snezana; Nelson, Andrew; Nelson, Timothy Knight; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neumann, Manuel; Neves, Ricardo; Nevski, Pavel; Newcomer, Mitchel; Newman, Paul; Nguyen, Duong Hai; Nickerson, Richard; Nicolaidou, Rosy; Nicquevert, Bertrand; Nielsen, Jason; Nikiforou, Nikiforos; Nikiforov, Andriy; Nikolaenko, Vladimir; Nikolic-Audit, Irena; Nikolics, Katalin; Nikolopoulos, Konstantinos; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nisius, Richard; Nobe, Takuya; Nodulman, Lawrence; Nomachi, Masaharu; Nomidis, Ioannis; Norberg, Scarlet; Nordberg, Markus; Nowak, Sebastian; Nozaki, Mitsuaki; Nozka, Libor; Ntekas, Konstantinos; Nunes Hanninger, Guilherme; Nunnemann, Thomas; Nurse, Emily; Nuti, Francesco; O'Brien, Brendan Joseph; O'grady, Fionnbarr; O'Neil, Dugan; O'Shea, Val; Oakham, Gerald; Oberlack, Horst; Obermann, Theresa; Ocariz, Jose; Ochi, Atsuhiko; Ochoa, Ines; Oda, Susumu; Odaka, Shigeru; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohman, Henrik; Ohshima, Takayoshi; Okamura, Wataru; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Olchevski, Alexander; Olivares Pino, Sebastian Andres; Oliveira Damazio, Denis; Oliver Garcia, Elena; Olivito, Dominick; Olszewski, Andrzej; Olszowska, Jolanta; Onofre, António; Onyisi, Peter; Oram, Christopher; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlando, Nicola; Oropeza Barrera, Cristina; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Otero y Garzon, Gustavo; Otono, Hidetoshi; Ouchrif, Mohamed; Ouellette, Eric; Ould-Saada, Farid; Ouraou, Ahmimed; Oussoren, Koen Pieter; Ouyang, Qun; Ovcharova, Ana; Owen, Mark; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pachal, Katherine; Pacheco Pages, Andres; Padilla Aranda, Cristobal; Pagáčová, Martina; Pagan Griso, Simone; Paganis, Efstathios; Pahl, Christoph; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Palestini, Sandro; Pallin, Dominique; Palma, Alberto; Palmer, Jody; Pan, Yibin; Panagiotopoulou, Evgenia; Panduro Vazquez, William; Pani, Priscilla; Panikashvili, Natalia; Panitkin, Sergey; Pantea, Dan; Paolozzi, Lorenzo; Papadopoulou, Theodora; Papageorgiou, Konstantinos; Paramonov, Alexander; Paredes Hernandez, Daniela; Parker, Michael Andrew; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pasqualucci, Enrico; Passaggio, Stefano; Passeri, Antonio; Pastore, Fernanda; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Patel, Nikhul; Pater, Joleen; Patricelli, Sergio; Pauly, Thilo; Pearce, James; Pedersen, Maiken; Pedraza Lopez, Sebastian; Pedro, Rute; Peleganchuk, Sergey; Pelikan, Daniel; Peng, Haiping; Penning, Bjoern; Penwell, John; Perepelitsa, Dennis; Perez Codina, Estel; Pérez García-Estañ, María Teresa; Perez Reale, Valeria; Perini, Laura; Pernegger, Heinz; Perrino, Roberto; Peschke, Richard; Peshekhonov, Vladimir; Peters, Krisztian; Peters, Yvonne; Petersen, Brian; Petersen, Jorgen; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petrolo, Emilio; Petrucci, Fabrizio; Petteni, Michele; Pettersson, Nora Emilia; Pezoa, Raquel; Phillips, Peter William; Piacquadio, Giacinto; Pianori, Elisabetta; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Piec, Sebastian Marcin; Piegaia, Ricardo; Pignotti, David; Pilcher, James; Pilkington, Andrew; Pina, João Antonio; Pinamonti, Michele; Pinder, Alex; Pinfold, James; Pingel, Almut; Pinto, Belmiro; Pires, Sylvestre; Pizio, Caterina; Pleier, Marc-Andre; Pleskot, Vojtech; Plotnikova, Elena; Plucinski, Pawel; Poddar, Sahill; Podlyski, Fabrice; Poettgen, Ruth; Poggioli, Luc; Pohl, David-leon; Pohl, Martin; Polesello, Giacomo; Policicchio, Antonio; Polifka, Richard; Polini, Alessandro; Pollard, Christopher Samuel; Polychronakos, Venetios; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Popovic, Dragan; Poppleton, Alan; Portell Bueso, Xavier; Pospelov, Guennady; Pospisil, Stanislav; Potamianos, Karolos; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Prabhu, Robindra; Pralavorio, Pascal; Pranko, Aliaksandr; Prasad, Srivas; Pravahan, Rishiraj; Prell, Soeren; Price, Darren; Price, Joe; Price, Lawrence; Prieur, Damien; Primavera, Margherita; Proissl, Manuel; Prokofiev, Kirill; Prokoshin, Fedor; Protopapadaki, Eftychia-sofia; Protopopescu, Serban; Proudfoot, James; Przybycien, Mariusz; Przysiezniak, Helenka; Ptacek, Elizabeth; Pueschel, Elisa; Puldon, David; Purohit, Milind; Puzo, Patrick; Pylypchenko, Yuriy; Qian, Jianming; Qin, Gang; Quadt, Arnulf; Quarrie, David; Quayle, William; Quilty, Donnchadha; Qureshi, Anum; Radeka, Veljko; Radescu, Voica; Radhakrishnan, Sooraj Krishnan; Radloff, Peter; Rados, Pere; Ragusa, Francesco; Rahal, Ghita; Rajagopalan, Srinivasan; Rammensee, Michael; Rammes, Marcus; Randle-Conde, Aidan Sean; Rangel-Smith, Camila; Rao, Kanury; Rauscher, Felix; Rave, Tobias Christian; Ravenscroft, Thomas; Raymond, Michel; Read, Alexander Lincoln; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reeves, Kendall; Rehnisch, Laura; Reinsch, Andreas; Reisin, Hernan; Relich, Matthew; Rembser, Christoph; Ren, Zhongliang; Renaud, Adrien; Rescigno, Marco; Resconi, Silvia; Resende, Bernardo; Rezanova, Olga; Reznicek, Pavel; Rezvani, Reyhaneh; Richter, Robert; Richter-Was, Elzbieta; Ridel, Melissa; Rieck, Patrick; Rijssenbeek, Michael; Rimoldi, Adele; Rinaldi, Lorenzo; Ritsch, Elmar; Riu, Imma; Rizatdinova, Flera; Rizvi, Eram; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Roda, Chiara; Rodrigues, Luis; Roe, Shaun; Røhne, Ole; Rolli, Simona; Romaniouk, Anatoli; Romano, Marino; Romeo, Gaston; Romero Adam, Elena; Rompotis, Nikolaos; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Anthony; Rose, Matthew; Rosendahl, Peter Lundgaard; Rosenthal, Oliver; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rosten, Rachel; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Royon, Christophe; Rozanov, Alexandre; Rozen, Yoram; Ruan, Xifeng; Rubbo, Francesco; Rubinskiy, Igor; Rud, Viacheslav; Rudolph, Christian; Rudolph, Matthew Scott; Rühr, Frederik; Ruiz-Martinez, Aranzazu; Rurikova, Zuzana; Rusakovich, Nikolai; Ruschke, Alexander; Rutherfoord, John; Ruthmann, Nils; Ryabov, Yury; Rybar, Martin; Rybkin, Grigori; Ryder, Nick; Saavedra, Aldo; Sacerdoti, Sabrina; Saddique, Asif; Sadeh, Iftach; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Sakamoto, Hiroshi; Sakurai, Yuki; Salamanna, Giuseppe; Salamon, Andrea; Saleem, Muhammad; Salek, David; Sales De Bruin, Pedro Henrique; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvachua Ferrando, Belén; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sampsonidis, Dimitrios; Sanchez, Arturo; Sánchez, Javier; Sanchez Martinez, Victoria; Sandaker, Heidi; Sander, Heinz Georg; Sanders, Michiel; Sandhoff, Marisa; Sandoval, Tanya; Sandoval, Carlos; Sandstroem, Rikard; Sankey, Dave; Sansoni, Andrea; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Santoyo Castillo, Itzebelt; Sapp, Kevin; Sapronov, Andrey; Saraiva, João; Sarrazin, Bjorn; Sartisohn, Georg; Sasaki, Osamu; Sasaki, Yuichi; Satsounkevitch, Igor; Sauvage, Gilles; Sauvan, Emmanuel; Savard, Pierre; Savu, Dan Octavian; Sawyer, Craig; Sawyer, Lee; Saxon, James; Sbarra, Carla; Sbrizzi, Antonio; Scanlon, Tim; Scannicchio, Diana; Scarcella, Mark; Schaarschmidt, Jana; Schacht, Peter; Schaefer, Douglas; Schaefer, Ralph; Schaelicke, Andreas; Schaepe, Steffen; Schaetzel, Sebastian; Schäfer, Uli; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R. Dean; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Scherzer, Max; Schiavi, Carlo; Schieck, Jochen; Schillo, Christian; Schioppa, Marco; Schlenker, Stefan; Schmidt, Evelyn; Schmieden, Kristof; Schmitt, Christian; Schmitt, Christopher; Schmitt, Sebastian; Schneider, Basil; Schnellbach, Yan Jie; Schnoor, Ulrike; Schoeffel, Laurent; Schoening, Andre; Schoenrock, Bradley Daniel; Schorlemmer, Andre Lukas; Schott, Matthias; Schouten, Doug; Schovancova, Jaroslava; Schram, Malachi; Schramm, Steven; Schreyer, Manuel; Schroeder, Christian; Schuh, Natascha; Schultens, Martin Johannes; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwartzman, Ariel; Schwegler, Philipp; Schwemling, Philippe; Schwienhorst, Reinhard; Schwindling, Jerome; Schwindt, Thomas; Schwoerer, Maud; Sciacca, Gianfranco; Scifo, Estelle; Sciolla, Gabriella; Scott, Bill; Scuri, Fabrizio; Scutti, Federico; Searcy, Jacob; Sedov, George; Sedykh, Evgeny; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Sekula, Stephen; Selbach, Karoline Elfriede; Seliverstov, Dmitry; Sellers, Graham; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Serre, Thomas; Seuster, Rolf; Severini, Horst; Sforza, Federico; Sfyrla, Anna; Shabalina, Elizaveta; Shamim, Mansoora; Shan, Lianyou; Shank, James; Shao, Qi Tao; Shapiro, Marjorie; Shatalov, Pavel; Shaw, Kate; Sherwood, Peter; Shimizu, Shima; Shimmin, Chase Owen; Shimojima, Makoto; Shiyakova, Mariya; Shmeleva, Alevtina; Shochet, Mel; Short, Daniel; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Shushkevich, Stanislav; Sicho, Petr; Sidorov, Dmitri; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silbert, Ohad; Silva, José; Silver, Yiftah; Silverstein, Daniel; Silverstein, Samuel; Simak, Vladislav; Simard, Olivier; Simic, Ljiljana; Simion, Stefan; Simioni, Eduard; Simmons, Brinick; Simoniello, Rosa; Simonyan, Margar; Sinervo, Pekka; Sinev, Nikolai; Sipica, Valentin; Siragusa, Giovanni; Sircar, Anirvan; Sisakyan, Alexei; Sivoklokov, Serguei; Sjölin, Jörgen; Sjursen, Therese; Skinnari, Louise Anastasia; Skottowe, Hugh Philip; Skovpen, Kirill; Skubic, Patrick; Slater, Mark; Slavicek, Tomas; Sliwa, Krzysztof; Smakhtin, Vladimir; Smart, Ben; Smestad, Lillian; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snidero, Giacomo; Snow, Joel; Snyder, Scott; Sobie, Randall; Socher, Felix; Sodomka, Jaromir; Soffer, Abner; Soh, Dart-yin; Solans, Carlos; Solar, Michael; Solc, Jaroslav; Soldatov, Evgeny; Soldevila, Urmila; Solfaroli Camillocci, Elena; Solodkov, Alexander; Solovyanov, Oleg; Solovyev, Victor; Sommer, Philip; Song, Hong Ye; Soni, Nitesh; Sood, Alexander; Sopko, Vit; Sopko, Bruno; Sorin, Veronica; Sosebee, Mark; Soualah, Rachik; Soueid, Paul; Soukharev, Andrey; South, David; Spagnolo, Stefania; Spanò, Francesco; Spearman, William Robert; Spighi, Roberto; Spigo, Giancarlo; Spousta, Martin; Spreitzer, Teresa; Spurlock, Barry; St Denis, Richard Dante; Staerz, Steffen; Stahlman, Jonathan; Stamen, Rainer; Stanecka, Ewa; Stanek, Robert; Stanescu, Cristian; Stanescu-Bellu, Madalina; Stanitzki, Marcel Michael; Stapnes, Steinar; Starchenko, Evgeny; Stark, Jan; Staroba, Pavel; Starovoitov, Pavel; Staszewski, Rafal; Stavina, Pavel; Steele, Genevieve; Steinberg, Peter; Stekl, Ivan; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stern, Sebastian; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoebe, Michael; Stoerig, Kathrin; Stoicea, Gabriel; Stolte, Philipp; Stonjek, Stefan; Stradling, Alden; Straessner, Arno; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strauss, Emanuel; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Stroynowski, Ryszard; Stucci, Stefania Antonia; Stugu, Bjarne; Styles, Nicholas Adam; Su, Dong; Su, Jun; Subramania, Halasya Siva; Subramaniam, Rajivalochan; Succurro, Antonella; Sugaya, Yorihito; Suhr, Chad; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Susinno, Giancarlo; Sutton, Mark; Suzuki, Yu; Svatos, Michal; Swedish, Stephen; Swiatlowski, Maximilian; Sykora, Ivan; Sykora, Tomas; Ta, Duc; Tackmann, Kerstin; Taenzer, Joe; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takahashi, Yuta; Takai, Helio; Takashima, Ryuichi; Takeda, Hiroshi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tam, Jason; Tamsett, Matthew; Tan, Kong Guan; Tanaka, Junichi; Tanaka, Reisaburo; Tanaka, Satoshi; Tanaka, Shuji; Tanasijczuk, Andres Jorge; Tani, Kazutoshi; Tannoury, Nancy; Tapprogge, Stefan; Tarem, Shlomit; Tarrade, Fabien; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tashiro, Takuya; Tassi, Enrico; Tavares Delgado, Ademar; Tayalati, Yahya; Taylor, Christopher; Taylor, Frank; Taylor, Geoffrey; Taylor, Wendy; Teischinger, Florian Alfred; Teixeira Dias Castanheira, Matilde; Teixeira-Dias, Pedro; Temming, Kim Katrin; Ten Kate, Herman; Teng, Ping-Kun; Terada, Susumu; Terashi, Koji; Terron, Juan; Terzo, Stefano; Testa, Marianna; Teuscher, Richard; Therhaag, Jan; Theveneaux-Pelzer, Timothée; Thoma, Sascha; Thomas, Juergen; Thomas-Wilsker, Joshuha; Thompson, Emily; Thompson, Paul; Thompson, Peter; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Thomson, Mark; Thong, Wai Meng; Thun, Rudolf; Tian, Feng; Tibbetts, Mark James; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tiouchichine, Elodie; Tipton, Paul; Tisserant, Sylvain; Todorov, Theodore; Todorova-Nova, Sharka; Toggerson, Brokk; Tojo, Junji; Tokár, Stanislav; Tokushuku, Katsuo; Tollefson, Kirsten; Tomlinson, Lee; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Topilin, Nikolai; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Tran, Huong Lan; Trefzger, Thomas; Tremblet, Louis; Tricoli, Alessandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Tripiana, Martin; Triplett, Nathan; Trischuk, William; Trocmé, Benjamin; Troncon, Clara; Trottier-McDonald, Michel; Trovatelli, Monica; True, Patrick; Trzebinski, Maciej; Trzupek, Adam; Tsarouchas, Charilaos; Tseng, Jeffrey; Tsiareshka, Pavel; Tsionou, Dimitra; Tsipolitis, Georgios; Tsirintanis, Nikolaos; Tsiskaridze, Shota; Tsiskaridze, Vakhtang; Tskhadadze, Edisher; Tsukerman, Ilya; Tsulaia, Vakhtang; Tsuno, Soshi; Tsybychev, Dmitri; Tua, Alan; Tudorache, Alexandra; Tudorache, Valentina; Tuna, Alexander Naip; Tupputi, Salvatore; Turchikhin, Semen; Turecek, Daniel; Turk Cakir, Ilkay; Turra, Ruggero; Tuts, Michael; Tykhonov, Andrii; Tylmad, Maja; Tyndel, Mike; Uchida, Kirika; Ueda, Ikuo; Ueno, Ryuichi; Ughetto, Michael; Ugland, Maren; Uhlenbrock, Mathias; Ukegawa, Fumihiko; Unal, Guillaume; Undrus, Alexander; Unel, Gokhan; Ungaro, Francesca; Unno, Yoshinobu; Urbaniec, Dustin; Urquijo, Phillip; Usai, Giulio; Usanova, Anna; Vacavant, Laurent; Vacek, Vaclav; Vachon, Brigitte; Valencic, Nika; Valentinetti, Sara; Valero, Alberto; Valery, Loic; Valkar, Stefan; Valladolid Gallego, Eva; Vallecorsa, Sofia; Valls Ferrer, Juan Antonio; Van Berg, Richard; Van Der Deijl, Pieter; van der Geer, Rogier; van der Graaf, Harry; Van Der Leeuw, Robin; van der Ster, Daniel; van Eldik, Niels; van Gemmeren, Peter; Van Nieuwkoop, Jacobus; van Vulpen, Ivo; van Woerden, Marius Cornelis; Vanadia, Marco; Vandelli, Wainer; Vaniachine, Alexandre; Vankov, Peter; Vannucci, Francois; Vardanyan, Gagik; Vari, Riccardo; Varnes, Erich; Varol, Tulin; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vazeille, Francois; Vazquez Schroeder, Tamara; Veatch, Jason; Veloso, Filipe; Veneziano, Stefano; Ventura, Andrea; Ventura, Daniel; Venturi, Manuela; Venturi, Nicola; Venturini, Alessio; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Viazlo, Oleksandr; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Vigne, Ralph; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinogradov, Vladimir; Virzi, Joseph; Vitells, Ofer; Vivarelli, Iacopo; Vives Vaque, Francesc; Vlachos, Sotirios; Vladoiu, Dan; Vlasak, Michal; Vogel, Adrian; Vokac, Petr; Volpi, Guido; Volpi, Matteo; von der Schmitt, Hans; von Radziewski, Holger; von Toerne, Eckhard; Vorobel, Vit; Vorobev, Konstantin; Vos, Marcel; Voss, Rudiger; Vossebeld, Joost; Vranjes, Nenad; Vranjes Milosavljevic, Marija; Vrba, Vaclav; Vreeswijk, Marcel; Vu Anh, Tuan; Vuillermet, Raphael; Vukotic, Ilija; Vykydal, Zdenek; Wagner, Wolfgang; Wagner, Peter; Wahrmund, Sebastian; Wakabayashi, Jun; Walder, James; Walker, Rodney; Walkowiak, Wolfgang; Wall, Richard; Waller, Peter; Walsh, Brian; Wang, Chao; Wang, Chiho; Wang, Fuquan; Wang, Haichen; Wang, Hulin; Wang, Jike; Wang, Jin; Wang, Kuhan; Wang, Rui; Wang, Song-Ming; Wang, Tan; Wang, Xiaoxiao; Warburton, Andreas; Ward, Patricia; Wardrope, David Robert; Warsinsky, Markus; Washbrook, Andrew; Wasicki, Christoph; Watanabe, Ippei; Watkins, Peter; Watson, Alan; Watson, Ian; Watson, Miriam; Watts, Gordon; Watts, Stephen; Waugh, Ben; Webb, Samuel; Weber, Michele; Weber, Stefan Wolf; Webster, Jordan S; Weidberg, Anthony; Weigell, Philipp; Weinert, Benjamin; Weingarten, Jens; Weiser, Christian; Weits, Hartger; Wells, Phillippa; Wenaus, Torre; Wendland, Dennis; Weng, Zhili; Wengler, Thorsten; Wenig, Siegfried; Wermes, Norbert; Werner, Matthias; Werner, Per; Wessels, Martin; Wetter, Jeffrey; Whalen, Kathleen; White, Andrew; White, Martin; White, Ryan; White, Sebastian; Whiteson, Daniel; Wicke, Daniel; Wickens, Fred; Wiedenmann, Werner; Wielers, Monika; Wienemann, Peter; Wiglesworth, Craig; Wiik-Fuchs, Liv Antje Mari; Wijeratne, Peter Alexander; Wildauer, Andreas; Wildt, Martin Andre; Wilkens, Henric George; Will, Jonas Zacharias; Williams, Hugh; Williams, Sarah; Willis, Christopher; Willocq, Stephane; Wilson, John; Wilson, Alan; Wingerter-Seez, Isabelle; Winkelmann, Stefan; Winklmeier, Frank; Wittgen, Matthias; Wittig, Tobias; Wittkowski, Josephine; Wollstadt, Simon Jakob; Wolter, Marcin Wladyslaw; Wolters, Helmut; Wosiek, Barbara; Wotschack, Jorg; Woudstra, Martin; Wozniak, Krzysztof; Wright, Michael; Wu, Mengqing; Wu, Sau Lan; Wu, Xin; Wu, Yusheng; Wulf, Evan; Wyatt, Terry Richard; Wynne, Benjamin; Xella, Stefania; Xiao, Meng; Xu, Da; Xu, Lailin; Yabsley, Bruce; Yacoob, Sahal; Yamada, Miho; Yamaguchi, Hiroshi; Yamaguchi, Yohei; Yamamoto, Akira; Yamamoto, Kyoko; Yamamoto, Shimpei; Yamamura, Taiki; Yamanaka, Takashi; Yamauchi, Katsuya; Yamazaki, Yuji; Yan, Zhen; Yang, Haijun; Yang, Hongtao; Yang, Un-Ki; Yang, Yi; Yanush, Serguei; Yao, Liwen; Yao, Weiming; Yasu, Yoshiji; Yatsenko, Elena; Yau Wong, Kaven Henry; Ye, Jingbo; Ye, Shuwei; Yen, Andy L; Yildirim, Eda; Yilmaz, Metin; Yoosoofmiya, Reza; Yorita, Kohei; Yoshida, Rikutaro; Yoshihara, Keisuke; Young, Charles; Young, Christopher John; Youssef, Saul; Yu, David Ren-Hwa; Yu, Jaehoon; Yu, Jiaming; Yu, Jie; Yuan, Li; Yurkewicz, Adam; Zabinski, Bartlomiej; Zaidan, Remi; Zaitsev, Alexander; Zaman, Aungshuman; Zambito, Stefano; Zanello, Lucia; Zanzi, Daniele; Zaytsev, Alexander; Zeitnitz, Christian; Zeman, Martin; Zemla, Andrzej; Zengel, Keith; Zenin, Oleg; Ženiš, Tibor; Zerwas, Dirk; Zevi della Porta, Giovanni; Zhang, Dongliang; Zhang, Fangzhou; Zhang, Huaqiao; Zhang, Jinlong; Zhang, Lei; Zhang, Xueyao; Zhang, Zhiqing; Zhao, Zhengguo; Zhemchugov, Alexey; Zhong, Jiahang; Zhou, Bing; Zhou, Lei; Zhou, Ning; Zhu, Cheng Guang; Zhu, Hongbo; Zhu, Junjie; Zhu, Yingchun; Zhuang, Xuai; Zibell, Andre; Zieminska, Daria; Zimine, Nikolai; Zimmermann, Christoph; Zimmermann, Robert; Zimmermann, Simone; Zimmermann, Stephanie; Zinonos, Zinonas; Ziolkowski, Michael; Zitoun, Robert; Zobernig, Georg; Zoccoli, Antonio; zur Nedden, Martin; Zurzolo, Giovanni; Zutshi, Vishnu; Zwalinski, Lukasz

    2014-07-15

    The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton-proton collision data collected in 2011 at $\\sqrt{s}$ = 7 TeV and corresponding to an integrated luminosity of 4.7 fb$^{-1}$. Tag-and-probe methods using events with leptonic decays of $W$ and $Z$ bosons and $J/\\psi$ mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil level for electron transverse energy greater than 30 GeV.

  8. The Higgs portal above threshold

    Energy Technology Data Exchange (ETDEWEB)

    Craig, Nathaniel [Department of Physics, University of California,Santa Barbara, CA 93106 (United States); Lou, Hou Keong [Department of Physics, Princeton University,Princeton, NJ 08540 (United States); McCullough, Matthew [Theory Division, CERN,1211 Geneva 23 (Switzerland); Thalapillil, Arun [Department of Physics and Astronomy, Rutgers University,Piscataway, NJ 08854 (United States)

    2016-02-18

    The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of searches in these channels at √s=14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.

  9. The Higgs portal above threshold

    International Nuclear Information System (INIS)

    Craig, Nathaniel; Lou, Hou Keong; McCullough, Matthew; Thalapillil, Arun

    2016-01-01

    The discovery of the Higgs boson opens the door to new physics interacting via the Higgs Portal, including motivated scenarios relating to baryogenesis, dark matter, and electroweak naturalness. We systematically explore the collider signatures of singlet scalars produced via the Higgs Portal at the 14 TeV LHC and a prospective 100 TeV hadron collider. We focus on the challenging regime where the scalars are too heavy to be produced in the decays of an on-shell Higgs boson, and instead are produced primarily via an off-shell Higgs. Assuming these scalars escape the detector, promising channels include missing energy in association with vector boson fusion, monojets, and top pairs. We forecast the sensitivity of searches in these channels at √s=14 & 100 TeV and compare collider reach to the motivated parameter space of singlet-assisted electroweak baryogenesis, Higgs Portal dark matter, and neutral naturalness.

  10. Simple solution-processed titanium oxide electron transport layer for efficient inverted polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Liang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Shen, Wenfei [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Institute of Hybrid Materials, Laboratory of New Fiber Materials and Modern Textile—The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071 (China); Chen, Weichao [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Bao, Xichang, E-mail: baoxc@qibebt.ac.cn [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Wang, Ning; Dou, Xiaowei; Han, Liangliang; Wen, Shuguang [CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China)

    2014-12-31

    Titanium oxide (TiO{sub X}) is an effective electron transport layer (ETL) in polymer solar cells (PSCs). We report efficient inverted PSCs with a simple solution-processed amorphous TiO{sub X} (s-TiO{sub X}) film as an ETL. The s-TiO{sub X} film with high light transmittance was prepared by spin-coating titanium (IV) isopropoxide isopropanol solution on indium tin oxide coated glass in inert and then placed in air under room temperature for 60 min. The introduction of s-TiO{sub X} ETL greatly improved the short circuit current density of the devices. PSCs based on poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester and poly(4,8-bis-alkyloxy-benzo[1,2-b:4,5-b′]dithiophene-alt-alkylcarbonyl -thieno[3,4-b]thiophene):[6,6]-phenyl- C71-butyric acid methyl ester using s-TiO{sub X} film as ETL shows high power conversion efficiency of 4.29% and 6.7% under the illumination of AM 1.5G, 100 mW/cm{sup 2}, which shows enhancements compared to the conventional PSCs with poly(styrenesulfonate)-doped poly(ethylenedioxythiophene) as anode buffer layer. In addition, the device exhibits good stability in a humid ambient atmosphere without capsulation. The results indicate that the annealing-free, simple solution processed s-TiO{sub X} film is an efficient ETL for high-performance PSCs. - Highlights: • High quality s-TiO{sub X} films were prepared by a simple, solution method without thermal treatment. • The s-TiO{sub X} films with high transmittance are very smooth. • The organic photovoltaic performance with s-TiO{sub X} film improved greatly and exhibited good stability. • The annealing-free, simple prepared s-TiO{sub X} film will be much compatible with flexible substrates.

  11. Acute pain management efficiency improves with point-of-care handheld electronic billing system.

    Science.gov (United States)

    Fahy, Brenda G

    2009-02-01

    Technology advances continue to impact patient care and physician workflow. To enable more efficient performance of billing activities, a point-of-care (POC) handheld computer technology replaced a paper-based system on an acute pain management service. Using a handheld personal digital assistant (PDA) and software from MDeverywhere (MDe, MDeverywhere, Long Island, NY), we performed a 1-yr prospective observational study of an anesthesiology acute pain management service billings and collections. Seventeen anesthesiologists providing billable acute pain services were trained and entered their charges on a PDA. Twelve months of data, just before electronic implementation (pre-elec), were compared to a 12-m period after implementation (post-elec). The total charges were 4883 for 890 patients pre-elec and 5368 for 1128 patients post-elec. With adoption of handheld billing, the charge lag days decreased from 29.3 to 7.0 (P billing using PDAs to replace a paper-based billing system improved the collection rate and decreased the number of charge lag days with a positive return on investment. The handheld PDA billing system provided POC support for physicians during their daily clinical (e.g., patient locations, rounding lists) and billing activities, improving workflow.

  12. An efficient and reproducible process for transmission electron microscopy (TEM) of rare cell populations

    Science.gov (United States)

    Kumar, Sachin; Ciraolo, Georgianne; Hinge, Ashwini; Filippi, Marie-Dominique

    2014-01-01

    Transmission electron microscopy (TEM) provides ultra-structural details of cells at the sub-organelle level. However, details of the cellular ultrastructure, and the cellular organization and content of various organelles in rare populations, particularly in the suspension, like hematopoietic stem cells (HSCs) remained elusive. This is mainly due to the requirement of millions of cells for TEM studies. Thus, there is a vital requirement of a method that will allow TEM studies with low cell numbers of such rare populations. We describe an alternative and novel approach for TEM studies for rare cell populations. Here we performed TEM study from 10,000 HSC cells with quite ease. In particular, tiny cell pellets were identified by Evans blue staining after PFA-GA fixation. The cell pellet was pre-embedded in agarose in a small microcentrifuge tube and processed for dehydration, infiltration and embedding. Semi-thin and ultra-thin sections identified clusters of numerous cells per sections with well preserved morphology and ultrastructural details of golgi complex and mitochondria. Together, this method provides an efficient, easy and reproducible process to perform qualitative and quantitative TEM analysis from limited biological samples including cells in suspension. PMID:24291346

  13. Building an Archival Collections Portal

    Directory of Open Access Journals (Sweden)

    Stuart Marquis

    2008-06-01

    Full Text Available Columbia University Libraries has developed the Archival Collections Portal, a unified search system helping users discover archival resources in a streamlined way. We combined the power of Lucene and Solr to search XML, parse JSON objects, create EAD-compliant documents, and deliver results in an easy-to-use interface. By reusing MARC records and employing new search engine features and techniques, we are able to bring important and hard-to-find collections to researchers and archivists. The canonical home page of the Portal is http://www.columbia.edu/library/archival/.

  14. 29 CFR 785.24 - Principles noted in Portal-to-Portal Bulletin.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Principles noted in Portal-to-Portal Bulletin. 785.24 Section 785.24 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR... of Principles Preparatory and Concluding Activities § 785.24 Principles noted in Portal-to-Portal...

  15. The Investigation of Electron Beam Catalytical Oxidation Process Efficiency with Potassium Persulfate in Removal Humic Acid from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    MT Ghaneian

    2015-05-01

    Results: Based on the results, changes in pH had little effect on the Humic acid removal efficiency. The average, with increasing of pH from 4 to 10, the removal efficiency of humic acid from 72.59% to 73.36% increased, respectively. The results showed that increasing of the dose from 1 to 15 kGy, humic acid removal efficiency increases. Based on results by increasing of persulfate concentration, the removal efficiency increased so that with increasing of concentration of potassium persulfate from 0.1 to 0.5 mmol/100cc, removal efficiency from 69.43% to 83.82% was increased. Kinetic experiments showed that the decomposition of humic acid by electron beam radiation followed the second-order kinetic. Conclusion: The data from this study showed that the aqueous solution containing acid Humic is decomposed effectively by electron beams irradiation. Addition of potassium persulfate can be have significant improvements in removal efficiency of humic acid in the presence of electron beam.

  16. Highly Efficient Flexible Quantum Dot Solar Cells with Improved Electron Extraction Using MgZnO Nanocrystals.

    Science.gov (United States)

    Zhang, Xiaoliang; Santra, Pralay Kanti; Tian, Lei; Johansson, Malin B; Rensmo, Håkan; Johansson, Erik M J

    2017-08-22

    Colloidal quantum dot (CQD) solar cells have high potential for realizing an efficient and lightweight energy supply for flexible or wearable electronic devices. To achieve highly efficient and flexible CQD solar cells, the electron transport layer (ETL), extracting electrons from the CQD solid layer, needs to be processed at a low-temperature and should also suppress interfacial recombination. Herein, a highly stable MgZnO nanocrystal (MZO-NC) layer is reported for efficient flexible PbS CQD solar cells. Solar cells fabricated with MZO-NC ETL give a high power conversion efficiency (PCE) of 10.4% and 9.4%, on glass and flexible plastic substrates, respectively. The reported flexible CQD solar cell has the record efficiency to date of flexible CQD solar cells. Detailed theoretical simulations and extensive characterizations reveal that the MZO-NCs significantly enhance charge extraction from CQD solids and diminish the charge accumulation at the ETL/CQD interface, suppressing charge interfacial recombination. These important results suggest that the low-temperature processed MZO-NCs are very promising for use in efficient flexible solar cells or other flexible optoelectronic devices.

  17. From EGEE Operations Portal towards EGI Operations Portal

    Science.gov (United States)

    Cordier, Hélène; L'Orphelin, Cyril; Reynaud, Sylvain; Lequeux, Olivier; Loikkanen, Sinikka; Veyre, Pierre

    Grid operators in EGEE have been using a dedicated dashboard as their central operational tool, stable and scalable for the last 5 years despite continuous upgrade from specifications by users, monitoring tools or data providers. In EGEE-III, recent regionalisation of operations led the Operations Portal developers to conceive a standalone instance of this tool. We will see how the dashboard reorganization paved the way for the re-engineering of the portal itself. The outcome is an easily deployable package customized with relevant information sources and specific decentralized operational requirements. This package is composed of a generic and scalable data access mechanism, Lavoisier; a renowned php framework for configuration flexibility, Symfony and a MySQL database. VO life cycle and operational information, EGEE broadcast and Downtime notifications are next for the major reorganization until all other key features of the Operations Portal are migrated to the framework. Features specifications will be sketched at the same time to adapt to EGI requirements and to upgrade. Future work on feature regionalisation, on new advanced features or strategy planning will be tracked in EGI- Inspire through the Operations Tools Advisory Group, OTAG, where all users, customers and third parties of the Operations Portal are represented from January 2010.

  18. Use of a web portal among adult clinic patients seen for type 2 diabetes mellitus.

    Science.gov (United States)

    Coughlin, Steven S; Heboyan, Vahé; Williams, Lovoria B; Hatzigeorgiou, Christos

    2018-01-01

    To determine the number of adult clinic patients seen for type 2 diabetes mellitus (T2DM) at an academic medical center and to examine characteristics of those who had or had not registered for a web portal. Electronic records were reviewed to identify web portal registration by patients treated for T2DM by age, sex, race and Hispanic ethnicity, and service (General Internal Medicine, Endocrinology). A total of 1,401 patients with T2DM were seen in General Internal Medicine and Endocrinology outpatient clinics. Less than one third (32%) had registered for the web portal. Women were more likely to have registered for the web portal than men [odds ratio (OR) =1.25; 95% CI, 0.99-1.57; Pweb portal, along with those who were 56 to 60 and >66 years of age. In multivariate analysis, a statistically significant association was observed between web portal registration and General Internal Medicine clinic vs . Endocrinology clinic (OR =2.96, P18-25 years, male sex (adjusted OR =0.71, P=0.006), and Black race (OR =0.33, P<0.001). Additional research is needed to identify portal design features that improve glycemic control and interventions that will increase use of patient portals, especially among Black patients with T2DM and those with low health literacy or computer literacy.

  19. Quantitative vs. subjective portal verification using digital portal images.

    Science.gov (United States)

    Bissett, R; Leszczynski, K; Loose, S; Boyko, S; Dunscombe, P

    1996-01-15

    Off-line, computer-aided prescription (simulator) and treatment (portal) image registration using chamfer matching has been implemented on PC based viewing station. The purposes of this study were (a) to evaluate the performance of interactive anatomy and field edge extraction and subsequent registration, and (b) to compare observer's perceptions of field accuracy with measured discrepancies following anatomical registration. Prescription-treatment image pairs for 48 different patients were examined in this study. Digital prescription images were produced with the aid of a television camera and a digital frame grabber, while the treatment images were obtained directly from an on-line portal imaging system. To facilitate perception of low contrast anatomical detail, on-line portal images were enhanced with selective adaptive histogram equalization prior to extraction of anatomical edges. Following interactive extraction of anatomical and field border information by an experienced observer, the identified anatomy was registered using chamfer matching. The degree of conformity between the prescription and treatment fields was quantified using several parameters, which included relative prescription field coverage and overcoverage, as well as the translational and rotational displacements as measured by chamfer matching applied to the boundaries of the two fields. These quantitative measures were compared with subjective evaluations made by four radiation oncologists. All the images in this series that included a range of the most commonly seen treatment sites were registered and the conformity parameters were found. The mean treatment/prescription field coverage and overcoverage were approximately 95 and 7%, respectively before registration. The mean translational displacement in the transverse and cranio-caudal directions were 2.9 and 3.4 mm, respectively. The mean rotational displacement was approximately 2 degrees. For all four oncologists, the portals classified

  20. Software tool for portal dosimetry research.

    Science.gov (United States)

    Vial, P; Hunt, P; Greer, P B; Oliver, L; Baldock, C

    2008-09-01

    This paper describes a software tool developed for research into the use of an electronic portal imaging device (EPID) to verify dose for intensity modulated radiation therapy (IMRT) beams. A portal dose image prediction (PDIP) model that predicts the EPID response to IMRT beams has been implemented into a commercially available treatment planning system (TPS). The software tool described in this work was developed to modify the TPS PDIP model by incorporating correction factors into the predicted EPID image to account for the difference in EPID response to open beam radiation and multileaf collimator (MLC) transmitted radiation. The processes performed by the software tool include; i) read the MLC file and the PDIP from the TPS, ii) calculate the fraction of beam-on time that each point in the IMRT beam is shielded by MLC leaves, iii) interpolate correction factors from look-up tables, iv) create a corrected PDIP image from the product of the original PDIP and the correction factors and write the corrected image to file, v) display, analyse, and export various image datasets. The software tool was developed using the Microsoft Visual Studio.NET framework with the C# compiler. The operation of the software tool was validated. This software provided useful tools for EPID dosimetry research, and it is being utilised and further developed in ongoing EPID dosimetry and IMRT dosimetry projects.

  1. Quality Control of Mega Voltage Portal Imaging System

    International Nuclear Information System (INIS)

    Diklic, A.; Dundara Debeljuh, D.; Jurkovic, S.; Smilovic Radojcic, D.; Svabic Kolacio; Kasabasic, M.; Faj, D.

    2013-01-01

    The Electronic Portal Imaging Device (EPID) is a system used to verify either the correct positioning of the patient during radiotherapy treatment or the linear accelerator beam parameters. The correct position of the patient corresponds to the position at which the patient was scanned at the CT simulator and according to which the therapy plan was made and optimized. Regarding this, besides the advanced treatment planning system and optimized treatment planning techniques, the day-to-day reproduction of simulated conditions is of great importance for the treatment outcome. Therefore, to verify the patient set-up portal imaging should be applied prior to the first treatment session and repeated according to treatment prescriptions during the treatment. In order to achieve full functionality and precision of the EPID, it must be included in radiotherapy Quality Control (QC) programme. The QC of the Mega Voltage portal imaging system was separated in two parts. In the first, the QC of the detector parameters should be performed. For this purpose, the FC2 and QC3 phantoms should be used, along with the Portal Image Processing System program (PIPSpro) package for data analysis. The second part of the QC of the linear accelerator's portal imaging system should include the QC of the CBCT. In this part a set of predefined manufacturer's tests using two different phantoms, one for the geometry calibration and the other for the image quality evaluation, should be performed. Also, the treatment conditions should be simulated using anthropomorphic phantoms and dose distributions for particular EPID protocols should be measured. Procedures for quality control of the portal imaging system developed and implemented at University Hospital Rijeka are presented in this paper.(author)

  2. Magnetic Resonance Imaging of a Liver Hydatid Cyst Invading the Portal Vein and Causing Portal Cavernomatosis.

    Science.gov (United States)

    Herek, Duygu; Sungurtekin, Ugur

    2015-01-01

    Hepatic hydatid cysts rarely invade portal veins causing portal cavernomatosis as a secondary complication. We report the case of a patient with direct invasion of the right portal vein by hydatid cysts causing portal cavernomatosis diagnosed via magnetic resonance imaging (MRI). The presented case highlights the useful application of MRI with T2-weighted images and gadolinium-enhanced T1-weighted images in the diagnosis of hepatic hydatid lesions presenting with a rare complication of portal cavernomatosis.

  3. The Anatomy of a Grid portal

    International Nuclear Information System (INIS)

    Licari, Daniele; Calzolari, Federico

    2011-01-01

    In this paper we introduce a new way to deal with Grid portals referring to our implementation. L-GRID is a light portal to access the EGEE/EGI Grid infrastructure via Web, allowing users to submit their jobs from a common Web browser in a few minutes, without any knowledge about the Grid infrastructure. It provides the control over the complete lifecycle of a Grid Job, from its submission and status monitoring, to the output retrieval. The system, implemented as client-server architecture, is based on the Globus Grid middleware. The client side application is based on a java applet; the server relies on a Globus User Interface. There is no need of user registration on the server side, and the user needs only his own X.509 personal certificate. The system is user-friendly, secure (it uses SSL protocol, mechanism for dynamic delegation and identity creation in public key infrastructures), highly customizable, open source, and easy to install. The X.509 personal certificate does not get out from the local machine. It allows to reduce the time spent for the job submission, granting at the same time a higher efficiency and a better security level in proxy delegation and management.

  4. The Anatomy of a Grid portal

    Science.gov (United States)

    Licari, Daniele; Calzolari, Federico

    2011-12-01

    In this paper we introduce a new way to deal with Grid portals referring to our implementation. L-GRID is a light portal to access the EGEE/EGI Grid infrastructure via Web, allowing users to submit their jobs from a common Web browser in a few minutes, without any knowledge about the Grid infrastructure. It provides the control over the complete lifecycle of a Grid Job, from its submission and status monitoring, to the output retrieval. The system, implemented as client-server architecture, is based on the Globus Grid middleware. The client side application is based on a java applet; the server relies on a Globus User Interface. There is no need of user registration on the server side, and the user needs only his own X.509 personal certificate. The system is user-friendly, secure (it uses SSL protocol, mechanism for dynamic delegation and identity creation in public key infrastructures), highly customizable, open source, and easy to install. The X.509 personal certificate does not get out from the local machine. It allows to reduce the time spent for the job submission, granting at the same time a higher efficiency and a better security level in proxy delegation and management.

  5. Highly efficient hybrid photovoltaics based on hyperbranched three-dimensional TiO2 electron transporting materials

    KAUST Repository

    Mahmood, Khalid; Swain, Bhabani Sankar; Amassian, Aram

    2015-01-01

    A 3D hyperbranched TiO2 electron transporting material is demonstrated, which exhibits superior carrier transport and lifetime, as well as excellent infiltration, leading to highly efficient mesostructured hybrid solar cells, such as lead-halide perovskites (15.5%) and dye-sensitized solar cells (11.2%).

  6. Highly efficient hybrid photovoltaics based on hyperbranched three-dimensional TiO2 electron transporting materials

    KAUST Repository

    Mahmood, Khalid

    2015-03-23

    A 3D hyperbranched TiO2 electron transporting material is demonstrated, which exhibits superior carrier transport and lifetime, as well as excellent infiltration, leading to highly efficient mesostructured hybrid solar cells, such as lead-halide perovskites (15.5%) and dye-sensitized solar cells (11.2%).

  7. Radiologic investigation of portal hypertension

    International Nuclear Information System (INIS)

    Becker, C.; Wegmueller, H.

    1993-01-01

    Radiologic evaluation of patients with portal hypertension in the pre- and postoperative period can be done with several non-invasive or invasive imaging modalities which offer complementary information. Doppler-ultrasonography (-US) is the method of choice for initial non-invasive screening as well as for follow-up tests after shunt surgery. The diagnostic information provided by Doppler-US regarding morphology and blood flow in the upper abdominal organs and vessels is sufficient in many instances. Dynamic computed tomography (CT), magnetic resonance tomography (MRT) and recently, magnetic resonance angiography (MRA) are additional non-invasive imaging techniques that may add valuable information if necessary. Conventional angiography is usually performed immediately prior to surgery to demonstrate the vascular morphology. The standard angiographic technique to demonstrate both the arterial and portal venous system is arterioportography (late-phase portography) by means of selective catheterization of the celiac, the splenic, the superior mesenteric or inferior mesenteric arteries. The dose of iodinated contrast material may be reduced by 50% if digital subtraction angiography is used instead of the conventional technique. Inferior venacavography and hepatic venography are indicated in patients with suspected postsinusoidal portal hypertension, e.g. the Budd-Chiari syndrome; hepatic wedge manometry offers valuable information regarding pressure gradients between the portal and systemic venous system prior to shunt surgery. The angiographic access through the inferior vena cava is also used for direct catheterization of surgical porto-caval or spleno-renal shunts for both angiography, manometry and, if necessary, balloon angioplasty. (authors)

  8. Sonographic detection of portal venous gas

    International Nuclear Information System (INIS)

    Lee, Wang Yul; Lee, S. K.; Cho, O. K.

    1989-01-01

    Portal venous gas suggests underlying bowel disease such as strangulating intestinal obstruction and its demonstration carries with it an important implications with respect to patient management. Radiography has been the gold standard for the detection of portal venous gas. We have experienced two cases of portal venous gas diagnosed by ultrasound. Sonographic findings were floating echoes in the main portal vein and highly echogenic linear or patchy echoes within the hepatic parenchyma. Simple abdominal films of those cases failed to demonstrate gas in the portal venous system

  9. Enhanced carrier collection efficiency and reduced quantum state absorption by electron doping in self-assembled quantum dot solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tian, E-mail: tianlee@umd.edu, E-mail: dage@ece.umd.edu; Dagenais, Mario, E-mail: tianlee@umd.edu, E-mail: dage@ece.umd.edu [Department of Electrical Engineering, University of Maryland, College Park, Maryland 20742 (United States); Lu, Haofeng; Fu, Lan; Tan, Hark Hoe; Jagadish, Chennupati [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia)

    2015-02-02

    Reduced quantum dot (QD) absorption due to state filling effects and enhanced electron transport in doped QDs are demonstrated to play a key role in solar energy conversion. Reduced QD state absorption with increased n-doping is observed in the self-assembled In{sub 0.5}Ga{sub 0.5}As/GaAs QDs from high resolution below-bandgap external quantum efficiency (EQE) measurement, which is a direct consequence of the Pauli exclusion principle. We also show that besides partial filling of the quantum states, electron-doping produces negatively charged QDs that exert a repulsive Coulomb force on the mobile electrons, thus altering the electron trajectory and reducing the probability of electron capture, leading to an improved collection efficiency of photo-generated carriers, as indicated by an absolute above-bandgap EQE measurement. The resulting redistribution of the mobile electron in the planar direction is further validated by the observed photoluminescence intensity dependence on doping.

  10. Computer tomographic findings in portal hypertension due to cirrhosis of the liver. Pt. 1

    International Nuclear Information System (INIS)

    Koester, O.; Kunz, R.; Fischer, P.; Lackner, K.; Koischwitz, D.; Bonn Univ.

    1983-01-01

    The CT findings in 80 patients with confirmed portal hypertension due to intrahepatic block were analysed retrospectively. The findings included ascites, hypo-dense areas in the liver, nodular or irregular liver contour, the inability of define intrahepatic portal vessels with narrow window settings, the so-called ''kissing'' sign and evidence of hepato-fugal collaterals and thickning of the wall of the oesophagus. Electronic measurements of various organs (liver, spleen) and vessel diameters (portal vein, superior mesenteric vein) provide parameters which permit classification of patients into the cirrhotic group, as compared with a control group. The statistical significance of this classification was checked by the Kolmogoroff-Smirnoff test. (orig.)

  11. Computer tomographic findings in portal hypertension due to cirrhosis of the liver. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Koester, O; Kunz, R; Fischer, P; Lackner, K; Koischwitz, D

    1983-06-01

    The CT findings in 80 patients with confirmed portal hypertension due to intrahepatic block were analysed retrospectively. The findings included ascites, hypo-dense areas in the liver, nodular or irregular liver contour, the inability of define intrahepatic portal vessels with narrow window settings, the so-called ''kissing'' sign and evidence of hepato-fugal collaterals and thickening of the wall of the oesophagus. Electronic measurements of various organs (liver, spleen) and vessel diameters (portal vein, superior mesenteric vein) provide parameters which permit classification of patients into the cirrhotic group, as compared with a control group. The statistical significance of this classification was checked by the Kolmogoroff-Smirnoff test.

  12. Therapeutic effects of percutaneous transhepatic variceal embolization combined with partial splenic embolization for portal hypertention

    International Nuclear Information System (INIS)

    Hua Yingxue; Yan Zhiping; Cheng Yongde; Qiao Delin; Zhou Bing; Chen Shiwei; Li Yong

    2007-01-01

    Objective: To evaluate the efficiency of percutaneous transhepatic variceal embolization (PTVE) combined with patial splenic embolization (PES)for portal hypertension. Methods: 30 patients with critical portal hypertension were divided randomly into two groups, 15 patients of A group underwent PSE PTVE combined with PSE and 15 of B group underwent PES only. The changes of collateral circulation of the two groups were compared via color Doppler ultrasonography pre-and postoperatively. Results: The hypersplenism was well controlled in both groups after PTVE and PSE. The varices of A group were embolized completely, the flow rate and velocity of portal blood stream were significantly reduced (P<0.05). In addition, the flow rate and velocity together with inner diameter of the azygous vein decreased (P<0.01), but no change shown on portal vein diameter, only with decrease of blood flow and velocity postoperatively were shown in the two groups (P<0.05). During 13-16 months follow-up, gastroesophageal variceal bleeding appeared in 2 patients and formation of portal thrombi in 1 patients of B group. There was no gastroesophageal variceal bleeding in A group but 2 patients appeared portal hypertensive gastroenteropathy (PHG)under endoscopic confirmations. Conclusion: PTVE combined PSE is very efficient for gastroesophageal variceal bleeding and hypersplenism due to portal hypertension, especially for patients with poor hepatic function, possessing simple, economic, less invasive properties and deserving to be recommended. (authors)

  13. Teen use of a patient portal: a qualitative study of parent and teen attitudes.

    Science.gov (United States)

    Bergman, David A; Brown, Nancy L; Wilson, Sandra

    2008-01-01

    We conducted a qualitative study of the attitudes of teens and parents toward the use of a patient portal. We conducted two teen and two parent focus groups, one teen electronic bulletin board, and one parent electronic bulletin board. Videotapes and transcripts from the groups were independently analyzed by two reviewers for significant themes, which were then validated by two other members of the research team. Twenty-eight teens and 23 parents participated in the groups. Significant themes included issues about teens' control of their own healthcare; enthusiasm about the use of a patient portal to access their providers, seek health information, and make appointments; and concerns about confidentiality. In summary, there was considerable support among teens and parents for a patient portal as well as concerns about confidentiality. The teen portal affords an opportunity to negotiate issues of confidentiality.

  14. Intelligent interaction based on holographic personalized portal

    Directory of Open Access Journals (Sweden)

    Yadong Huang

    2017-06-01

    Full Text Available Purpose – The purpose of this paper is to study the architecture of holographic personalized portal, user modeling, commodity modeling and intelligent interaction. Design/methodology/approach – In this paper, the authors propose crowd-science industrial ecological system based on holographic personalized portal and its interaction. The holographic personality portal is based on holographic enterprises, commodities and consumers, and the personalized portal consists of accurate ontology, reliable supply, intelligent demand and smart cyberspace. Findings – The personalized portal can realize the information acquisition, characteristic analysis and holographic presentation. Then, the intelligent interaction, e.g. demand decomposition, personalized search, personalized presentation and demand prediction, will be implemented within the personalized portal. Originality/value – The authors believe that their work on intelligent interaction based on holographic personalized portal, which has been first proposed in this paper, is innovation focusing on the interaction between intelligence and convenience.

  15. A heuristic approach to edge detection in on-line portal imaging

    International Nuclear Information System (INIS)

    McGee, Kiaran P.; Schultheiss, Timothy E.; Martin, Eric E.

    1995-01-01

    Purpose: Portal field edge detection is an essential component of several postprocessing techniques used in on-line portal imaging, including field shape verification, selective contrast enhancement, and treatment setup error detection. Currently edge detection of successive fractions in a multifraction portal image series involves the repetitive application of the same algorithm. As the number of changes in the field is small compared to the total number of fractions, standard edge detection algorithms essentially recalculate the same field shape numerous times. A heuristic approach to portal edge detection has been developed that takes advantage of the relatively few changes in the portal field shape throughout a fractionation series. Methods and Materials: The routine applies a standard edge detection routine to calculate an initial field edge and saves the edge information. Subsequent fractions are processed by applying an edge detection operator over a small region about each point of the previously defined contour, to determine any shifts in the field shape in the new image. Failure of this edge check indicates that a significant change in the field edge has occurred, and the original edge detection routine is applied to the image. Otherwise the modified edge contour is used to define the new edge. Results: Two hundred and eighty-one portal images collected from an electronic portal imaging device were processed by the edge detection routine. The algorithm accurately calculated each portal field edge, as well as reducing processing time in subsequent fractions of an individual portal field by a factor of up to 14. Conclusions: The heuristic edge detection routine is an accurate and fast method for calculating portal field edges and determining field edge setup errors

  16. Structure-function analysis of the DNA translocating portal of the bacteriophage T4 packaging machine.

    Science.gov (United States)

    Padilla-Sanchez, Victor; Gao, Song; Kim, Hyung Rae; Kihara, Daisuke; Sun, Lei; Rossmann, Michael G; Rao, Venigalla B

    2014-03-06

    Tailed bacteriophages and herpesviruses consist of a structurally well conserved dodecameric portal at a special 5-fold vertex of the capsid. The portal plays critical roles in head assembly, genome packaging, neck/tail attachment, and genome ejection. Although the structures of portals from phages φ29, SPP1, and P22 have been determined, their mechanistic roles have not been well understood. Structural analysis of phage T4 portal (gp20) has been hampered because of its unusual interaction with the Escherichia coli inner membrane. Here, we predict atomic models for the T4 portal monomer and dodecamer, and we fit the dodecamer into the cryo-electron microscopy density of the phage portal vertex. The core structure, like that from other phages, is cone shaped with the wider end containing the "wing" and "crown" domains inside the phage head. A long "stem" encloses a central channel, and a narrow "stalk" protrudes outside the capsid. A biochemical approach was developed to analyze portal function by incorporating plasmid-expressed portal protein into phage heads and determining the effect of mutations on head assembly, DNA translocation, and virion production. We found that the protruding loops of the stalk domain are involved in assembling the DNA packaging motor. A loop that connects the stalk to the channel might be required for communication between the motor and the portal. The "tunnel" loops that project into the channel are essential for sealing the packaged head. These studies established that the portal is required throughout the DNA packaging process, with different domains participating at different stages of genome packaging. © 2013.

  17. Patient portal readiness among postpartum patients in a safety net setting.

    Science.gov (United States)

    Wieland, Daryl; Gibeau, Anne; Dewey, Caitlin; Roshto, Melanie; Frankel, Hilary

    2017-07-05

    Maternity patients interact with the healthcare system over an approximately ten-month interval, requiring multiple visits, acquiring pregnancy-specific education, and sharing health information among providers. Many features of a web-based patient portal could help pregnant women manage their interactions with the healthcare system; however, it is unclear whether pregnant women in safety-net settings have the resources, skills or interest required for portal adoption. In this study of postpartum patients in a safety net hospital, we aimed to: (1) determine if patients have the technical resources and skills to access a portal, (2) gain insight into their interest in health information, and (3) identify the perceived utility of portal features and potential barriers to adoption. We developed a structured questionnaire to collect demographics from postpartum patients and measure use of technology and the internet, self-reported literacy, interest in health information, awareness of portal functions, and perceived barriers to use. The questionnaire was administered in person to women in an inpatient setting. Of the 100 participants surveyed, 95% reported routine internet use and 56% used it to search for health information. Most participants had never heard of a patient portal, yet 92% believed that the portal functions were important. The two most appealing functions were to check results and manage appointments. Most participants in this study have the required resources such as a device and familiarity with the internet to access a patient portal including an interest in interacting with a healthcare institution via electronic means. Pregnancy is a critical episode of care where active engagement with the healthcare system can influence outcomes. Healthcare systems and portal developers should consider ways to tailor a portal to address the specific health needs of a maternity population including those in a safety net setting.

  18. INCREASING EFFICIENCY OF ELECTRONIC PUBLIC SERVICES TO CITIZENS AND BUSINESSES IN CONNECTION WITH THE IMPLEMENTATION OF INTEGRATED ELECTRONIC SOLUTIONS

    Directory of Open Access Journals (Sweden)

    Popeangã Vasile Nicolae

    2010-07-01

    Full Text Available European Union enlargement, the existence of new needs and demands, requires the development of innovation and quality of public administration, which means improving public services in the global economy as a requirement of competitiveness. The European Union hopes to achieve the major objectives in what concerns the electronic government by 2010; actions necessary to achieve them are adopting solutions based on information and communication technologies in the Romanian public administration, aimed at developing modern public services. This paper presents some best experiences of e-governance in Romania and the results of e-governance in Gorj County, and the degree of implementation and use by citizens.

  19. The analysis of educational portals for the area of ICT profession.

    OpenAIRE

    Vrbka, Jan

    2011-01-01

    This diploma thesis deals with electronic educational portals and their applicability in the area of ICT. The aim is to determine key knowledge and skills of ICT professionals and assign those to courses from educational portals. The work is divided into theoretical and practical part. The theoretical part consists of definitions of issues elaborated in this work. The particular attention is paid to education and e-learning. Practical part seeks to match key professional knowledge and skills ...

  20. MyWelch: building an information portal system in a medical library environment.

    Science.gov (United States)

    Zhang, Dongming; Zambrowicz, Caroline; Zhou, Hong; Roderer, Nancy

    2003-01-01

    MyWelch is a medical library portal system that users can use to create customized web sites that reflect their research needs and personal interests. In the MyWelch environment, faculty and students are empowered to take a greater role in identifying their needs and determining their requirements in the electronic environment. The portal system also facilitates interaction among library users and staff.

  1. Nuclear Instrumentation Module (NIM) standard logic processor as a portal signal analyzer

    International Nuclear Information System (INIS)

    Minges, G.P.

    1978-01-01

    A general purpose electronic logic processor has been designed into a 2 wide NIM (Nuclear Instrumentation Module) bin module. The unit utilizes a microprocessor to achieve necessary versatility. The processor's first use is as a new generation signal analyzer for use in radiometric personnel and vehicle portal monitors. Significant improvements have been obtained in sensitivity and stability over existing analog discriminators. The new analyzer is presently being used to update personnel and vehicle portal monitoring systems

  2. Nonlinear effects and conversion efficiency of free electron laser in compton regime

    International Nuclear Information System (INIS)

    Taguchi, Toshihiro; Mima, Kunioki; Mochizuki, Takayasu

    1980-01-01

    Nonlinear evolutions of free electron laser are analyzed by using quasi-linear theory. By the analysis, the energy conversion rates and the spectral width of the emitted radiations are calculated self-consistently. Moreover, it is found that the energy conversion rate is remarkably improved, when a RF field is applied to reaccelerate electron beam. (author)

  3. Smooth Growth of Organic Semiconductor Films on Graphene for High-Efficiency Electronics

    NARCIS (Netherlands)

    Hlawacek, G.; Khokhar, F.S.; van Gastel, Raoul; Poelsema, Bene; Teichert, Christian

    2011-01-01

    High-quality thin films of conjugated molecules with smooth interfaces are important to assist the advent of organic electronics. Here, we report on the layer-by-layer growth of the organic semiconductor molecule p-sexiphenyl (6P) on the transparent electrode material graphene. Low energy electron

  4. Influence of Bernstein modes on the efficiency of electron cyclotron resonance x-ray source

    International Nuclear Information System (INIS)

    Andreev, V. V.; Nikitin, G.V.; Savanovich, V.Yu.; Umnov, A.M.; Elizarov, L.I.; Serebrennikov, K.S.; Vostrikova, E.A.

    2006-01-01

    The article considers the factors influencing the temperature of hot electron component in an electron cyclotron resonance (ECR) x-ray source. In such sources the electron heating occurs often due to extraordinary electromagnetic wave propagating perpendicularly to the magnetic field. In this case the possibility of the absorption of Bernstein modes is regarded as an additional mechanism of electron heating. The Bernstein modes in an ECR x-ray source can arise due to either linear transformation or parametric instability of external transversal wave. The article briefly reviews also the further experiments which will be carried out to study the influence of Bernstein modes on the increase of hot electron temperature and consequently of x-ray emission

  5. Addressing the efficiency roll-off in a fluorescent OLED by facile electron transport layer doping and carrier confinement

    Science.gov (United States)

    Soman, Anjaly; M, Manuraj; Unni, K. N. Narayanan

    2018-05-01

    Organic light emitting diodes (OLEDs) often face the issue of decreasing power efficiency with increasing brightness. Loss of charge carrier balance is one of the factors contributing to the efficiency roll-off. We demonstrate that by using a combination of doped electron transport layer (ETL) and a specially chosen electron blocking layer (EBL) having high hole mobility, this efficiency roll-off can be effectively suppressed. A tris-(8-hydroxyquinoline) aluminium (Alq3) based OLED has been fabricated with 2,3,6,7-Tetrahydro-1,1,7,7,-tetramethyl-1H, 5H,11H-10-(2-benzothiazolyl) quinolizino-[9,9a, 1n gh]coumarin (C545T) as the emissive dopant. Bulk doping of the ETL with lithium fluoride (LiF) was optimized to increase the luminous intensity as well as the current efficiency. An EBL with high hole mobility introduced between the EML and the hole transport layer (HTL) improved the performance drastically, and the device brightness at 9 V got improved by a factor of 2.5 compared to that of the control device. While increasing the brightness from 100 cd/m2 to 1000 cd/m2, the power efficiency drop was 47% for the control device whereas only a drop of 15% was observed for the modified device. The possible mechanisms for the enhanced performance are discussed.

  6. Aligning Work Processes and the Adviser Portal Bank System

    DEFF Research Database (Denmark)

    Jørgensen, Jens Bæk; Lassen, Kristian Bisgaard

    2006-01-01

    The Adviser Portal (AP) is a new IT system for 15 Danish banks. The main goal of AP is to increase the efficiency and quality of bank advisers’ work. Re- quirements engineering for AP includes describing new work processes that must be supported by AP using a combination of: (1) prose and informal...... drawings; (2) The Adviser Portal (AP) is a new IT system for 15 Danish banks. The main goal of AP is to increase the efficiency and quality of bank advisers' work. Requirements engineering for AP includes describing new work processes that musty be supported by AP using a combination of: (1) prose...... and informal drawings; (2) formal models; (3) graphical animation. This representation helps users and system analysts to align new work processes and AP via early experiments in a prototyping fashion. The contribution of this paper is to present and reflect upon the analysis and descrition of one specific...

  7. NUCLEONICA: a nuclear science portal

    International Nuclear Information System (INIS)

    Magill, J.; Galy, J.; Dreher, R.; Hamilton, D.; Tufan, M.; Normand, C.; Schwenk-Ferrero, A.; Wiese, H.W.

    2008-01-01

    NUCLEONICA is a new nuclear science web portal from the European Commission's Joint Research Centre. The portal provides a customizable, integrated environment and collaboration platform for the nuclear sciences using the latest 'Web 2.0' dynamic technology. NUCLEONICA is aimed at professionals, academics and students working with radionuclides in fields as diverse as the life sciences (e.g., biology, medicine, agriculture), the earth sciences (geology, meteorology, environmental science) and the more traditional disciplines such as nuclear power, health physics and radiation protection, nuclear and radio-chemistry, and astrophysics. It is also used as a knowledge management tool to preserve nuclear knowledge built up over many decades by creating modern web-based versions of so-called legacy computer codes. (authors)

  8. The secondary metabolite bioinformatics portal

    DEFF Research Database (Denmark)

    Weber, Tilmann; Kim, Hyun Uk

    2016-01-01

    . In this context, this review gives a summary of tools and databases that currently are available to mine, identify and characterize natural product biosynthesis pathways and their producers based on ‘omics data. A web portal called Secondary Metabolite Bioinformatics Portal (SMBP at http...... analytical and chemical methods gave access to this group of compounds, nowadays genomics-based methods offer complementary approaches to find, identify and characterize such molecules. This paradigm shift also resulted in a high demand for computational tools to assist researchers in their daily work......Natural products are among the most important sources of lead molecules for drug discovery. With the development of affordable whole-genome sequencing technologies and other ‘omics tools, the field of natural products research is currently undergoing a shift in paradigms. While, for decades, mainly...

  9. Editor's welcome, PORTAL, Vol. 1, No. 1, January 2004

    Directory of Open Access Journals (Sweden)

    Paul Allatson

    2004-01-01

    Full Text Available Welcome to the inaugural issue of PORTAL On behalf of the Executive Editorial Committee of PORTAL Journal of Multidisciplinary International Studies, it is a great pleasure to announce the virtual birth of this fully peer-reviewed journal under the auspices of UTSePress, the exciting new electronic publishing enterprise housed at the central library at the University of Technology, Sydney (UTS, Australia. PORTAL itself is edited by staff from the Institute for International Studies, a dynamic research and teaching centre at UTS. The launch of PORTAL's inaugural issue will take place simultaneously in Sydney, Australia, and Guadalajara, México, on January 28 (Sydney / 27 (Guadalajara 2004. The trans-Pacific axial enabling this twin launch is emblematic of the many axes of dialogue that, it is to be hoped, will characterize the content and reception of this and future issues of Portal. We are grateful to the many people at the Center for Social Sciences and Humanities at la Universidad de Guadalajara, México, for their provision of the technologies and tequila that will facilitate Portal's digital launch in a different space and timezone to its 'homebirth' in Sydney, Australia. As PORTAL's 'Focus and Scope' statement indicates, the journal is dedicated to publishing scholarship by practitioners of-and dissenters from-international, regional, area, migration, and ethnic studies. PORTAL is also committed to providing a space for cultural producers interested in the internationalization of cultures. With these aims in mind we have conceived PORTAL as a "multidisciplinary venture," to use Michel Chaouli's words. That is, PORTAL signifies "a place where researchers [and cultural producers] are exposed to different ways of posing questions and proffering answers, without creating out of their differing disciplinary languages a common theoretical or methodological pidgin" (2003, p. 57. Our hope is that scholars working in the humanities

  10. Quantitative vs. subjective portal verification using digital portal images

    International Nuclear Information System (INIS)

    Bissett, Randy; Leszczynski, Konrad; Loose, Stephen; Boyko, Susan; Dunscombe, Peter

    1996-01-01

    Purpose: Off-line, computer-aided prescription (simulator) and treatment (portal) image registration using chamfer matching has been implemented on PC based viewing station. The purposes of this study were (a) to evaluate the performance of interactive anatomy and field edge extraction and subsequent registration, and (b) to compare observer's perceptions of field accuracy with measured discrepancies following anatomical registration. Methods and Materials: Prescription-treatment image pairs for 48 different patients were examined in this study. Digital prescription images were produced with the aid of a television camera and a digital frame grabber, while the treatment images were obtained directly from an on-line portal imaging system. To facilitate perception of low contrast anatomical detail, on-line portal images were enhanced with selective adaptive histogram equalization prior to extraction of anatomical edges. Following interactive extraction of anatomical and field border information by an experienced observer, the identified anatomy was registered using chamber matching. The degree of conformity between the prescription and treatment fields was quantified using several parameters, which included relative prescription field coverage and overcoverage, as well as the translational and rotational displacements as measured by chamfer matching applied to the boundaries of the two fields. These quantitative measures were compared with subjective evaluations made by four radiation oncologists. Results: All the images in this series that included a range of the most commonly seen treatment sites were registered and the conformity parameters were found. The mean treatment/prescription field coverage and overcoverage were approximately 95 and 7%, respectively before registration. The mean translational displacement in the transverse and cranio-caudal directions were 2.9 and 3.4 mm, respectively. The mean rotational displacement was approximately 2 deg. . For all

  11. Heavy component of spent nuclear fuel: Efficiency of model-substance ionization by electron-induced discharge

    Energy Technology Data Exchange (ETDEWEB)

    Antonov, N. N., E-mail: antonovnickola@gmail.com; Gavrikov, A. V.; Samokhin, A. A.; Smirnov, V. P. [Russian Academy of Sciences, High Energy Density Research Center, Joint Institute for High Temperatures (Russian Federation)

    2016-12-15

    The method of plasma separation of spent nuclear fuel can be tested with a model substance which has to be transformed from the condensed to plasma state. For this purpose, electron-induced discharge in lead vapor injected into the interelectrode gap is simulated using the kinetic approach. The ionization efficiency, the electrostatic-potential distribution, and those of the ion and electron densities in the discharge gap are derived as functions of the discharge-current density and concentration of the vapor of the model substance. Given a discharge-current density of 3.5 A/cm{sup 2} and a lead-vapor concentration of 2 × 10{sup 12} cm{sup –3}, the simulated ionization efficiency proves to be nearly 60%. The discharge in lead vapor is also investigated experimentally.

  12. Efficient Ab-Initio Electron Transport Calculations for Heterostructures by the Nonequilibrium Green’s Function Method

    Directory of Open Access Journals (Sweden)

    Hirokazu Takaki

    2014-01-01

    Full Text Available We present an efficient computation technique for ab-initio electron transport calculations based on density functional theory and the nonequilibrium Green’s function formalism for application to heterostructures with two-dimensional (2D interfaces. The computational load for constructing the Green’s functions, which depends not only on the energy but also on the 2D Bloch wave vector along the interfaces and is thus catastrophically heavy, is circumvented by parallel computational techniques with the message passing interface, which divides the calculations of the Green’s functions with respect to energy and wave vectors. To demonstrate the computational efficiency of the present code, we perform ab-initio electron transport calculations of Al(100-Si(100-Al(100 heterostructures, one of the most typical metal-semiconductor-metal systems, and show their transmission spectra, density of states (DOSs, and dependence on the thickness of the Si layers.

  13. Enhanced efficiency of organic solar cells by using ZnO as an electron-transport layer

    Science.gov (United States)

    Ullah, Irfan; Shah, Said Karim; Wali, Sartaj; Hayat, Khizar; Khattak, Shaukat Ali; Khan, Aurangzeb

    2017-12-01

    This paper reports the use of ZnO, processed by sol-gel, as an efficient electron-transport layer for inverted organic photovoltaic cells. The device with incorporated ZnO interlayer, annealed at 100 °C, between transparent electrode and blend film plays an effective role in enhancing photovoltaic properties: the short-circuit current density (J sc) doubles while open-circuit voltage (V oc) and fill factor increase by 0.12 V and 10 %, respectively. Power conversion efficiency (PCE) of solar cell increases, approximately, three times. The improvement in the PCE is attributed to the presence of ZnO which, being an electron-facilitating layer, provides an energy step for charge collection at electrodes.

  14. Efficiency of the generation of impulsion by cyclotron waves currents of the electrons in an Axisymmetric Tokamak

    International Nuclear Information System (INIS)

    Gutierrez T, C.; Beltran P, M.

    2004-01-01

    The neoclassical theory of transport is used to calculate the current efficiency of electronic cyclotron impulsion (ECCD) in an axisymmetric tokamak in the few collisions regime. The standard parameter of the tokamak is used to obtain a system of equations that describe the hydrodynamic of the plasma, where the ponderomotive force (PM) due to high power radio frequency waves is taken in account. The PM force is produced in the proximity of electron cyclotron resonance surface in a specific poloidal localization. The efficiency ECCD is analyzed in the cases of first and second harmonic (for different angles of injection of radio frequency waves) and it is validated using the experimental values of the TCV and T-10 tokamaks. The results are according to those obtained by means of the techniques of the Green functions. (Author)

  15. Uzbekistan Radiation Portal Monitoring System

    International Nuclear Information System (INIS)

    Richardson, J; Knapp, R; Loshak, A; Yuldashev, B; Petrenko, V

    2005-01-01

    The work proposed in this presentation builds on the foundation set by the DTRA funded demonstration project begun in 2000 and completed in December of 2003. This previous work consisted of two phases whose overall objective was to install portal radiation monitors at four select ports-of-entry in Uzbekistan (Tashkent International Airport, Gisht-Kuprik (Kazakhstan border), Alat (Turkmenistan border), and Termez (Afghanistan border)) in order to demonstrate their effectiveness in preventing the illicit trafficking of nuclear materials. The objectives also included developing and demonstrating capabilities in the design, installation, operation, training, and maintenance of a radiation portal monitoring system. The system and demonstration project has proved successful in many ways. An effective working relationship among the Uzbekistan Customs Services, Uzbekistan Border Guards, and Uzbekistan Institute of Nuclear Physics has been developed. There has been unprecedented openness with the sharing of portal monitor data with Lawrence Livermore National Laboratory. The system has proved to be effective, with detection of illicit trafficking, and, at Alat, an arrest of three persons illegally transporting radioactive materials into Turkmenistan. The demonstration project has made Uzbekistan a model nonproliferation state in Central Asia and, with an expanded program, places them in a position to seal a likely transit route for illicit nuclear materials. These results will be described. In addition, this work is currently being expanded to include additional ports-of-entry in Uzbekistan. The process for deciding on which additional ports-of-entry to equip will also be described

  16. Treatment of portal hypertension caused by benign main portal vein stenosis with endovascular stent

    International Nuclear Information System (INIS)

    Huang Mingsheng; Shan Hong; Jiang Zaibo; Guan Shouhai; Zhu Kangshun; Li Zhengran; Zhou Yubin; He Bingjun

    2004-01-01

    Objective: To evaluate the value of endovascular stent in the treatment of portal hypertension caused by benign main portal vein stenosis. Methods: Portal vein stents were implanted in 6 patients with benign main portal vein stenosis (inflammatory stenosis in 3 cases, postprocedure of liver transplantation in another 3 cases). The change of portal vein pressure, the patency of portal vein, relative clinical symptoms, complications, and survival were evaluated. Results: Six metallic stents were successfully placed across the portal vein stenotic or obstructive lesions in all 6 patients. Mean portal venous pressure decreased significantly after stent implantation from (37.3 ± 4.7) cm H 2 O (1 cm H 2 O=0.098 kPa) to (18.0 ± 1.9) cm H 2 O (P<0.001). The portal blood flow was restored, and the symptoms caused by portal hypertension were eliminated. There was no severe procedure-related complication. Follow-up time was from 5 to 36 months. The portal vein remained patent during the follow-up. All patients survived except one patient who died of other complications of liver transplantation. Conclusion: Percutaneous portal vein stent placement for the treatment of the benign main portal vein stenosis is safe and effective. (authors)

  17. The effect of partial portal decompression on portal blood flow and effective hepatic blood flow in man: a prospective study.

    Science.gov (United States)

    Rosemurgy, A S; McAllister, E W; Godellas, C V; Goode, S E; Albrink, M H; Fabri, P J

    1995-12-01

    With the advent of transjugular intrahepatic porta-systemic stent shunt and the wider application of the surgically placed small diameter prosthetic H-graft portacaval shunt (HGPCS), partial portal decompression in the treatment of portal hypertension has received increased attention. The clinical results supporting the use of partial portal decompression are its low incidence of variceal rehemorrhage due to decreased portal pressures and its low rate of hepatic failure, possibly due to maintenance of blood flow to the liver. Surprisingly, nothing is known about changes in portal hemodynamics and effective hepatic blood flow following partial portal decompression. To prospectively evaluate changes in portal hemodynamics and effective hepatic blood flow brought about by partial portal decompression, the following were determined in seven patients undergoing HGPCS: intraoperative pre- and postshunt portal vein pressures and portal vein-inferior vena cava pressure gradients, intraoperative pre- and postshunt portal vein flow, and pre- and postoperative effective hepatic blood flow. With HGPCS, portal vein pressures and portal vein-inferior vena cava pressure gradients decreased significantly, although portal pressures remained above normal. In contrast to the significant decreases in portal pressures, portal vein blood flow and effective h