4D-CT-based target volume definition in stereotactic radiotherapy of lung tumours: Comparison with a conventional technique using individual margins

International Nuclear Information System (INIS)

Hof, Holger; Rhein, Bernhard; Haering, Peter; Kopp-Schneider, Annette; Debus, Juergen; Herfarth, Klaus

2009-01-01

Purpose: To investigate the dosimetric benefit of integration of 4D-CT in the planning target volume (PTV) definition process compared to conventional PTV definition using individual margins in stereotactic body radiotherapy (SBRT) of lung tumours. Material and methods: Two different PTVs were defined: PTV conv consisting of the helical-CT-based clinical target volume (CTV) enlarged isotropically for each spatial direction by the individually measured amount of motion in the 4D-CT, and PTV 4D encompassing the CTVs defined in the 4D-CT phases displaying the extremes of the tumour position. Tumour motion as well as volumetric and dosimetric differences and relations of both PTVs were evaluated. Results: Volumetric examinations revealed a significant reduction of the mean PTV by 4D-CT from 57.7 to 40.7 cm 3 (31%) (p 4D in PTV conv (r = -0.69, 90% confidence limits: -0.87 and -0.34, p = 0.007). Mean lung dose (MLD) was decreased significantly by 17% (p < 0.001). Conclusions: In SBRT of lung tumours the mere use of individual margins for target volume definition cannot compensate for the additional effects that the implementation of 4D-CT phases can offer.

The MSFC Collaborative Engineering Process for Preliminary Design and Concept Definition Studies

Science.gov (United States)

Mulqueen, Jack; Jones, David; Hopkins, Randy

2011-01-01

This paper describes a collaborative engineering process developed by the Marshall Space Flight Center's Advanced Concepts Office for performing rapid preliminary design and mission concept definition studies for potential future NASA missions. The process has been developed and demonstrated for a broad range of mission studies including human space exploration missions, space transportation system studies and in-space science missions. The paper will describe the design team structure and specialized analytical tools that have been developed to enable a unique rapid design process. The collaborative engineering process consists of integrated analysis approach for mission definition, vehicle definition and system engineering. The relevance of the collaborative process elements to the standard NASA NPR 7120.1 system engineering process will be demonstrated. The study definition process flow for each study discipline will be will be outlined beginning with the study planning process, followed by definition of ground rules and assumptions, definition of study trades, mission analysis and subsystem analyses leading to a standardized set of mission concept study products. The flexibility of the collaborative engineering design process to accommodate a wide range of study objectives from technology definition and requirements definition to preliminary design studies will be addressed. The paper will also describe the applicability of the collaborative engineering process to include an integrated systems analysis approach for evaluating the functional requirements of evolving system technologies and capabilities needed to meet the needs of future NASA programs.

Potential impact of 68Ga-PSMA-11 PET/CT on prostate cancer definitive radiation therapy planning.

Science.gov (United States)

Calais, Jérémie; Kishan, Amar U; Cao, Minsong; Fendler, Wolfgang P; Eiber, Matthias; Herrmann, Ken; Ceci, Francesco; Reiter, Robert E; Matthew, Rettig B; Hegde, John V; Shaverdian, Narek; King, Christopher R; Steinberg, Michael L; Czernin, Johannes; Nickols, Nicholas G

2018-04-13

Background: Standard-of-care imaging for initial staging of prostate cancer (PCa) underestimates disease burden. Prostate specific membrane antigen (PSMA) positron emission tomography/ computed tomography (PET/CT) detects PCa metastasis with superior accuracy with potential impact definitive radiation therapy (RT) planning for non-metastatic PCa. Objectives: i) To determine how often definitive PCa RT planning based on standard target volumes cover 68 Ga-PSMA-11 PET/CT defined disease, and ii) To assess the potential impact of 68 Ga-PSMA-11 PET/CT on definitive PCa RT planning. Patients and Methods: This is a post-hoc analysis of an intention to treat population of 73 patients with localized PCa without prior local therapy who underwent 68 Ga-PSMA PET/CT for initial staging as part of an Investigational New Drug trial. 11/73 were intermediate-risk (15%), 33/73 were high-risk (45%), 22/73 were very high risk (30%), and 7/73 were N1 (9.5%). Clinical target volumes (CTVs) that included the prostate, seminal vesicles, and pelvic lymph nodes (LNs) using Radiation Therapy Oncology Group (RTOG) consensus guidelines were contoured on the CT portion of the PET/CT by a radiation oncologist blinded to the PET findings. 68 Ga-PSMA-11 PET/CT images were analyzed by a nuclear medicine physician. PSMA-positive lesions not covered by planning volumes based on the CTVs were considered to have a major potential impact on treatment planning. Results: All patients had PSMA-positive primary prostate lesion(s). 25/73 (34%) and 7/73 (9.5%) had PSMA-positive pelvic nodal and distant metastases, respectively. The sites of nodal metastases in decreasing order of frequency were external iliac (20.5%), common iliac (13.5%), internal iliac (12.5%) obturator (12.5%), perirectal (4%), abdominal (4%), upper-diaphragm (4%), and presacral (1.5%). The median size of the nodal lesions was 6 mm (range 4-24 mm). RT planning based on the CTVs covered 69/73 (94.5%) of primary disease and 20/25 (80%) of

Supercritical Carbon Dioxide Power Generation System Definition: Concept Definition and Capital Cost Estimate

Energy Technology Data Exchange (ETDEWEB)

Stoddard, Larry [Black & Veatch, Kansas City, MO (United States); Galluzzo, Geoff [Black & Veatch, Kansas City, MO (United States); Andrew, Daniel [Black & Veatch, Kansas City, MO (United States); Adams, Shannon [Black & Veatch, Kansas City, MO (United States)

2016-06-30

The Department of Energy’s (DOE’s) Office of Renewable Power (ORP) has been tasked to provide effective program management and strategic direction for all of the DOE’s Energy Efficiency & Renewable Energy’s (EERE’s) renewable power programs. The ORP’s efforts to accomplish this mission are aligned with national energy policies, DOE strategic planning, EERE’s strategic planning, Congressional appropriation, and stakeholder advice. ORP is supported by three renewable energy offices, of which one is the Solar Energy Technology Office (SETO) whose SunShot Initiative has a mission to accelerate research, development and large scale deployment of solar technologies in the United States. SETO has a goal of reducing the cost of Concentrating Solar Power (CSP) by 75 percent of 2010 costs by 2020 to reach parity with base-load energy rates, and 30 percent further reductions by 2030. The SunShot Initiative is promoting the implementation of high temperature CSP with thermal energy storage allowing generation during high demand hours. The SunShot Initiative has funded significant research and development work on component testing, with attention to high temperature molten salts, heliostats, receiver designs, and high efficiency high temperature supercritical CO₂ (sCO2) cycles. DOE retained Black & Veatch to support SETO’s SunShot Initiative for CSP solar power tower technology in the following areas: 1. Concept definition, including costs and schedule, of a flexible test facility to be used to test and prove components in part to support financing. 2. Concept definition, including costs and schedule, of an integrated high temperature molten salt (MS) facility with thermal energy storage and with a supercritical CO₂ cycle generating approximately 10MWe. 3. Concept definition, including costs and schedule, of an integrated high temperature falling particle facility with thermal energy storage and with a supercritical CO₂ cycle

Molten Salt: Concept Definition and Capital Cost Estimate

Energy Technology Data Exchange (ETDEWEB)

Stoddard, Larry [Black & Veatch, Kansas City, MO (United States); Andrew, Daniel [Black & Veatch, Kansas City, MO (United States); Adams, Shannon [Black & Veatch, Kansas City, MO (United States); Galluzzo, Geoff [Black & Veatch, Kansas City, MO (United States)

2016-06-30

The Department of Energy’s (DOE’s) Office of Renewable Power (ORP) has been tasked to provide effective program management and strategic direction for all of the DOE’s Energy Efficiency & Renewable Energy’s (EERE’s) renewable power programs. The ORP’s efforts to accomplish this mission are aligned with national energy policies, DOE strategic planning, EERE’s strategic planning, Congressional appropriation, and stakeholder advice. ORP is supported by three renewable energy offices, of which one is the Solar Energy Technology Office (SETO) whose SunShot Initiative has a mission to accelerate research, development and large scale deployment of solar technologies in the United States. SETO has a goal of reducing the cost of Concentrating Solar Power (CSP) by 75 percent of 2010 costs by 2020 to reach parity with base-load energy rates, and to reduce costs 30 percent further by 2030. The SunShot Initiative is promoting the implementation of high temperature CSP with thermal energy storage allowing generation during high demand hours. The SunShot Initiative has funded significant research and development work on component testing, with attention to high temperature molten salts, heliostats, receiver designs, and high efficiency high temperature supercritical CO₂ (sCO2) cycles. DOE retained Black & Veatch to support SETO’s SunShot Initiative for CSP solar power tower technology in the following areas: 1. Concept definition, including costs and schedule, of a flexible test facility to be used to test and prove components in part to support financing. 2. Concept definition, including costs and schedule, of an integrated high temperature molten salt (MS) facility with thermal energy storage and with a supercritical CO₂ cycle generating approximately 10MWe. 3. Concept definition, including costs and schedule, of an integrated high temperature falling particle facility with thermal energy storage and with a supercritical CO₂

Interreligious Communication (Definition, Concepts, Situation

Directory of Open Access Journals (Sweden)

Vahid Safi Esfahani

2015-12-01

Full Text Available Abstract Religion and monotheistic beliefs are the bases of the human societies and culture and communications are the most important manifestations of these bases. About the three elements of religion, culture and communications, which act as the distinctions of human beings from other beings, and the relationship among them, many discussions have been occurred. In this article, the definitions offered for religion, culture and communication and their relationship, using the literature governing the Intercultural Communication and Cross-cultural Communication as two subjects discussed in the field of Cultural Communication and International Communication, have been reviewed and tried through a novel method to promote the level of religion from a concept usually seen as something such as race, ethnic, identity and life style under the title of international communication and cultural communication to a much higher position and place it under the title of interreligious communication. Following creation of a new field of study, many of the scholars and thinkers who are concerned about that field get together and focus of its issues and try to offer definitions and divisions about the subject. Later, after accumulation of scientific materials about different issues in the field, the human knowledge in that subject starts to develop further and in a more organized way. In this regard, first, the preferred definitions of religion, culture, communication, and Interreligious Communication will be offered. Accordingly, every society includes a meaning structure which is called culture and communication would act as an interaction tool in this system whose task is coding and decoding. Religion is considered the origin of culture and the director of communication. Based on these primary definitions, the interreligious communication is defined as: the relationship between or among the monotheistic religions based on the common understanding of religious

Interreligious Communication (Definition, Concepts, Situation

Directory of Open Access Journals (Sweden)

Hasan Bashir

2016-01-01

Full Text Available Abstract Religion and monotheistic beliefs are the bases of the human societies and culture and communications are the most important manifestations of these bases. About the three elements of religion, culture and communications, which act as the distinctions of human beings from other beings, and the relationship among them, many discussions have been occurred. In this article, the definitions offered for religion, culture and communication and their relationship, using the literature governing the Intercultural Communication and Cross-cultural Communication as two subjects discussed in the field of Cultural Communication and International Communication, have been reviewed and tried through a novel method to promote the level of religion from a concept usually seen as something such as race, ethnic, identity and life style under the title of international communication and cultural communication to a much higher position and place it under the title of interreligious communication. Following creation of a new field of study, many of the scholars and thinkers who are concerned about that field get together and focus of its issues and try to offer definitions and divisions about the subject. Later, after accumulation of scientific materials about different issues in the field, the human knowledge in that subject starts to develop further and in a more organized way. In this regard, first, the preferred definitions of religion, culture, communication, and Interreligious Communication will be offered. Accordingly, every society includes a meaning structure which is called culture and communication would act as an interaction tool in this system whose task is coding and decoding. Religion is considered the origin of culture and the director of communication. Based on these primary definitions, the interreligious communication is defined as: the relationship between or among the monotheistic religions based on the common understanding of religious

ITER concept definition. V.1

International Nuclear Information System (INIS)

1989-01-01

Under the auspices of the International Atomic Energy Agency (IAEA), an agreement among the four parties representing the world's major fusion programs resulted in a program for conceptual design of the next logical step in the fusion program, the International Thermonuclear Experimental Reactor (ITER). The definition phase, which ended in November, 1989, is summarized in two reports: a brief summary is contained in the ITER Definition Phase Report (IAEA/ITER/DS/2); the extended technical summary and technical details of ITER are contained in this two-volume report. The first volume of this report contains the Introduction and Summary, and the remainder will appear in Volume II. In the Conceptual Design Activities phase, ITER has been defined as being a tokamak device. The basic performance parameters of ITER are given in Volume I of this report. In addition, the rationale for selection of this concept, the performance flexibility, technical issues, operations, safety, reliability, cost, and research and development needed to proceed with the design are discussed. Figs and tabs

Cortical region of interest definition on SPECT brain images using X-ray CT registration

Energy Technology Data Exchange (ETDEWEB)

Tzourio, N.; Sutton, D. (Commissariat a l' Energie Atomique, Orsay (France). Service Hospitalier Frederic Joliot); Joliot, M. (Commissariat a l' Energie Atomique, Orsay (France). Service Hospitalier Frederic Joliot INSERM, Orsay (France)); Mazoyer, B.M. (Commissariat a l' Energie Atomique, Orsay (France). Service Hospitalier Frederic Joliot Antenne d' Information Medicale, C.H.U. Bichat, Paris (France)); Charlot, V. (Hopital Louis Mourier, Colombes (France). Service de Psychiatrie); Salamon, G. (CHU La Timone, Marseille (France). Service de Neuroradiologie)

1992-11-01

We present a method for brain single photon emission computed tomography (SPECT) analysis based on individual registration of anatomical (CT) and functional ([sup 133]Xe regional cerebral blood flow) images and on the definition of three-dimensional functional regions of interest. Registration of CT and SPECT is performed through adjustment of CT-defined cortex limits to the SPECT image. Regions are defined by sectioning a cortical ribbon on the CT images, copied over the SPECT images and pooled through slices to give 3D cortical regions of interest. The proposed method shows good intra- and interobserver reproducibility (regional intraclass correlation coefficient [approx equal]0.98), and good accuracy in terms of repositioning ([approx equal]3.5 mm) as compared to the SPECT image resolution (14 mm). The method should be particularly useful for analysing SPECT studies when variations in brain anatomy (normal or abnormal) must be accounted for. (orig.).

Identifying problematic concepts in SNOMED CT using a lexical approach.

Science.gov (United States)

Agrawal, Ankur; Perl, Yehoshua; Elhanan, Gai

2013-01-01

SNOMED CT (SCT) has been endorsed as a premier clinical terminology by many organizations with a perceived use within electronic health records and clinical information systems. However, there are indications that, at the moment, SCT is not optimally structured for its intended use by healthcare practitioners. A study is conducted to investigate the extent of inconsistencies among the concepts in SCT. A group auditing technique to improve the quality of SCT is introduced that can help identify problematic concepts with a high probability. Positional similarity sets are defined, which are groups of concepts that are lexically similar and the position of the differing word in the fully specified name of the concepts of a set that correspond to each other. A manual auditing of a sample of such sets found 38% of the sets exhibiting one or more inconsistent concepts. Group auditing techniques such as this can thus be very helpful to assure the quality of SCT, which will help expedite its adoption as a reference terminology for clinical purposes.

Lay Worker Health Literacy: A Concept Analysis and Operational Definition.

Science.gov (United States)

Cadman, Kathleen Paco

2017-10-01

The concept of lay worker health literacy is created by concurrently analyzing and synthesizing two intersecting concepts, lay workers and health literacy. Articulation of this unique intersection is the result of implementing a simplified Wilson's Concept Analysis Procedure. This process incorporates the following components: a) selecting a concept, b) determining the aims/purposes of analysis, c) identifying all uses of the concept, d) determining defining attributes, e) identifying a model case, f) identifying borderline, related, contrary, and illegitimate cases, g) identifying antecedents and consequences, and h) defining empirical referents. Furthermore, as current literature provides no operational definition for lay worker health literacy, one is created to contribute cohesion to the concept. © 2017 Wiley Periodicals, Inc.

Concept definition of traffic flow wide-area surveillance

Energy Technology Data Exchange (ETDEWEB)

Allgood, G.O.; Ferrell, R.K.; Kercel, S.W.

1994-07-01

Traffic management can be thought of as a stochastic queuing process where the serving time at one of its control points is dynamically linked to the global traffic pattern, which is, in turn, dynamically linked to the control point. For this closed-loop system to be effective, the traffic management system must sense and interpret large spatial projections of data originating from multiple sensor suites. The intent of the Wide-Area Surveillance (WAS) Project is to build upon this concept and define the operational specifications and characteristics of a Traffic Flow Wide-Area Surveillance (TFWAS) system in terms of traffic management and control. In doing so, the functional capabilities of a TFWAS will be mapped onto an operational profile that is consistent with the Federal Highway Administration`s Intelligent Vehicle Highway System. This document provides the underlying foundation of this work by offering a concept definition for the TFWAS system. It concentrates on answering the question: ``What is the system?`` In doing so, the report develops a hierarchy of specialized definitions.

Voluntary euthanasia: ethical concepts and definitions.

Science.gov (United States)

Sanders, K; Chaloner, C

Euthanasia is a highly emotive and contentious subject, giving rise to a great deal of debate. However, despite its frequent exposure in public and professional media, there appears to be a lack of clarity about the concepts and definitions used in the euthanasia debate. This suggests that discussions on this subject are inadequately informed and ineffectual. The ethical focus of the euthanasia debate concerns the moral legitimacy of 'voluntary euthanasia'. This article provides an overview and clarification of some of the key ethical issues at the centre of that debate.

The essence of frailty: A systematic review and qualitative synthesis on frailty concepts and definitions.

Science.gov (United States)

Junius-Walker, Ulrike; Onder, Graziano; Soleymani, Dagmar; Wiese, Birgitt; Albaina, Olatz; Bernabei, Roberto; Marzetti, Emanuele

2018-05-31

One of the major threats looming over the growing older population is frailty. It is a distinctive health state characterised by increased vulnerability to internal and external stressors. Although the presence of frailty is well acknowledged, its concept and operationalisation are hampered by the extraordinary phenotypical and biological complexity. Yet, a widely accepted conception is needed to offer tailored policies and approaches. The ADVANTAGE Group aims to analyse the diverse frailty concepts to uncover the essence of frailty as a basis for a shared understanding. A systematic literature review was performed on frailty concepts and definitions from 2010 onwards. Eligible publications were reviewed using concept analysis that led to the extraction of text data for the themes "definition", "attributes", "antecedents", "consequences", and "related concepts". Qualitative description was used to further analyse the extracted text passages, leading to inductively developed categories on the essence of frailty. 78 publications were included in the review, and 996 relevant text passages were extracted for analysis. Five components constituted a comprehensive definition: vulnerability, genesis, features, characteristics, and adverse outcomes. Each component is described in more detail by a set of defining and explanatory criteria. An underlying functional perspective of health or its impairments is most compatible with the entity of frailty. The recent findings facilitate a focus on the relevant building blocks that define frailty. They point to the commonalities of the diverse frailty concepts and definitions. Based on these components, a widely accepted broad definition of frailty comes into range. Copyright © 2018 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Auditing description-logic-based medical terminological systems by detecting equivalent concept definitions

NARCIS (Netherlands)

Cornet, Ronald; Abu-Hanna, Ameen

2008-01-01

OBJECTIVE: To specify and evaluate a method for auditing medical terminological systems (TSs) based on detecting concepts with equivalent definitions. This method addresses two important problems: redundancy, where the same concept is represented more than once (described by different terms), and

The Use of SNOMED CT for Representing Concepts Used in Preoperative Guidelines

NARCIS (Netherlands)

Ahmadian, Leila; de Keizer, Nicolette F.; Cornet, Ronald

2009-01-01

The use of guidelines to improve quality of care depends on presenting them in a standard machine-interpretable form and using common terms in guidelines as well as in patient records. In this study, the use of SNOMED CT for representing concepts used in preoperative assessment guidelines was

Diagnostic accuracy of high-definition CT coronary angiography in high-risk patients

International Nuclear Information System (INIS)

Iyengar, S.S.; Morgan-Hughes, G.; Ukoumunne, O.; Clayton, B.; Davies, E.J.; Nikolaou, V.; Hyde, C.J.; Shore, A.C.; Roobottom, C.A.

2016-01-01

Aim: To assess the diagnostic accuracy of computed tomography coronary angiography (CTCA) using a combination of high-definition CT (HD-CTCA) and high level of reader experience, with invasive coronary angiography (ICA) as the reference standard, in high-risk patients for the investigation of coronary artery disease (CAD). Materials and methods: Three hundred high-risk patients underwent HD-CTCA and ICA. Independent experts evaluated the images for the presence of significant CAD, defined primarily as the presence of moderate (≥50%) stenosis and secondarily as the presence of severe (≥70%) stenosis in at least one coronary segment, in a blinded fashion. HD-CTCA was compared to ICA as the reference standard. Results: No patients were excluded. Two hundred and six patients (69%) had moderate and 178 (59%) had severe stenosis in at least one vessel at ICA. The sensitivity, specificity, positive predictive value, and negative predictive value were 97.1%, 97.9%, 99% and 93.9% for moderate stenosis, and 98.9%, 93.4%, 95.7% and 98.3%, for severe stenosis, on a per-patient basis. Conclusion: The combination of HD-CTCA and experienced readers applied to a high-risk population, results in high diagnostic accuracy comparable to ICA. Modern generation CT systems in experienced hands might be considered for an expanded role. - Highlights: • Diagnostic accuracy of High-Definition CT Angiography (HD-CTCA) has been assessed. • Invasive Coronary angiography (ICA) is the reference standard. • Diagnostic accuracy of HD-CTCA is comparable to ICA. • Diagnostic accuracy is not affected by coronary calcium or stents. • HD-CTCA provides a non-invasive alternative in high-risk patients.

Justifying threshold voltage definition for undoped body transistors through 'crossover point' concept

International Nuclear Information System (INIS)

Baruah, Ratul Kumar; Mahapatra, Santanu

2009-01-01

Two different definitions, one is potential based and the other is charge based, are used in the literatures to define the threshold voltage of undoped body symmetric double gate transistors. This paper, by introducing a novel concept of crossover point, proves that the charge based definition is more accurate than the potential based definition. It is shown that for a given channel length the potential based definition predicts anomalous change in threshold voltage with body thickness variation while the charge based definition results in monotonous change. The threshold voltage is then extracted from drain current versus gate voltage characteristics using linear extrapolation, transconductance and match-point methods. In all the three cases it is found that trend of threshold voltage variation support the charge based definition.

Satellite Power Systems (SPS) concept definition study. Volume 6: SPS technology requirements and verification

Science.gov (United States)

Hanley, G.

1978-01-01

Volume 6 of the SPS Concept Definition Study is presented and also incorporates results of NASA/MSFC in-house effort. This volume includes a supporting research and technology summary. Other volumes of the final report that provide additional detail are as follows: (1) Executive Summary; (2) SPS System Requirements; (3) SPS Concept Evolution; (4) SPS Point Design Definition; (5) Transportation and Operations Analysis; and Volume 7, SPS Program Plan and Economic Analysis.

Towards a Definition of Role-related Concepts for Business Modeling

NARCIS (Netherlands)

Meertens, Lucas Onno; Iacob, Maria Eugenia; Nieuwenhuis, Lambertus Johannes Maria

2010-01-01

Abstract—While several role-related concepts play an important role in business modeling, their definitions, relations, and use differ greatly between languages, papers, and reports. Due to this, the knowledge captured by models is not transferred correctly, and models are incomparable. In this

Feasibility of [18F]FDG-PET and coregistered CT on clinical target volume definition of advanced non-small cell lung cancer

International Nuclear Information System (INIS)

Messa, C.; IBFM-CNR, Milan; Scientific Institute H.S. Raffaele, Milan; Ceresoli, G.L.; Gregorc, V.; Rizzo, G.; Scientific Institute H.S. Raffaele, Milan; Artioli, D.; Cattaneo, M.; Castellone, P.; Picchio, M.; Landoni, C.; Scientific Institute H.S. Raffaele, Milan; Fazio, F.; IBFM-CNR, Milan; Scientific Institute H.S. Raffaele, Milan; Scientific Institute H.S. Raffaele, Milan

2005-01-01

Aim. To prospectively evaluate the impact of co registered positron emission tomography (PET) and computed tomography (CT) in 3D conformal radiotherapy (3D-CRT) planning in patients with non-small lung cancer (NSCLC). Methods. Twenty-one patients (median age: 57 years; range: 42-80 years) referred to 3D-CRT for NSCLC were recruited. Positron emission tomography with 18 F-fluorodeoxyglucose ([ 18 F]FDG-PET) and conventional CT images were coregistered (PET/CT images) using a commerciaI software package based on surface matching technique. Neoplastic areas were contoured on [ 18 F]FDGPET images with the aid of the correspondent CT image by a nuclear medicine physician. CT images and their relative PET contours were then transferred to treatment planning system. A radiation oncologist firstly contoured clinical target volumes (CTV) on CT scan alone (CTV-CT), and then on co registered PET/CT images (CTV-PET/CT). CTV-CT and CTV-PET/CT were compared for each patient; a difference higher than 25% was considered of clinical relevance. Results. Three patients were shifted to palliative radiotherapy for metastatic disease or very large tumor size, showed by [ 18 F]FDG-PET. Of the remaining 18 patients a CTV change, after inclusion of PET/CT data, was observed in 10/18 cases (55%): larger in 7/18 (range 33-279%) and smaller in 3/18 patients (range 26-34%), mainly due to inclusion or exclusion of Iymph-nodal disease and to better definition of tumor extent. CTV changes smaller than 25% occurred in the remaining 8/18 patients. Conclusion. [ 18 F]FDG-PET and CT images co-registration in radiotherapy treatment planning Ied to a change in CTV definition in the majority of our patients, which may signillcantly modify management and radiation treatment modality in these patients

A three-dimensional CT-based target definition for elective irradiation of the neck

International Nuclear Information System (INIS)

Nowak, Peter J.C.M.; Wijers, Oda B.; Lagerwaard, Frank J.; Levendag, Peter C.

1999-01-01

Introduction: Elective treatment of the clinically node-negative neck by radiation results in excellent control rates. However, radiation therapy with its organ-preserving properties is not without morbidity. Side effects of elective neck irradiation are mainly due to damage of the major and minor salivary glands, resulting in the dry mouth syndrome. Given that RT is the preferred treatment modality in case of elective treatment of the neck in many institutions, it is of utmost importance to try and reduce the associated sequelae of RT. Material and Methods: With the introduction of CT-planning systems and the development of 3D conformal radiation therapy (3D CRT) techniques, it has become feasible to deliver adequate doses of radiation to the target (neck) and at the same time saving (parts of) the salivary glands from doses beyond tolerance. A prerequisite for these techniques is that they require a precise knowledge of the target (i.e., of the elective neck) on CT. To be able to correlate borders of the surgical levels in the neck (I-VI) with structures seen on CT, an anatomical study, using two fixed (phenol, formaldehyde) human cadavers, was performed. Subsequently, the 6 potential lymph node regions in the neck on CT were defined. Results and Discussion: The reference for the current 3D CT-based definition of the lymph node regions in the neck is the official report of the American Academy of Otolaryngology, describing, based on surgical anatomy, the lymph node groups in the neck by Levels I-VI. The present investigation depicts reproducible landmarks on transversal CT images, corresponding to anatomical reference structures known from surgical levels (I-VI) and, this way, CT-based lymph node regions (1-6) were constructed

Differential-associative processing or example elaboration: Which strategy is best for learning the definitions of related and unrelated concepts?

Science.gov (United States)

Hannon, Brenda

2012-10-01

Definitions of related concepts (e.g., genotype - phenotype ) are prevalent in introductory classes. Consequently, it is important that educators and students know which strategy(s) work best for learning them. This study showed that a new comparative elaboration strategy, called differential-associative processing, was better for learning definitions of related concepts than was an integrative elaborative strategy, called example elaboration. This outcome occurred even though example elaboration was administered in a naturalistic way (Experiment 1) and students spent more time in the example elaboration condition learning (Experiments 1, 2, 3), and generating pieces of information about the concepts (Experiments 2 and 3). Further, with unrelated concepts ( morpheme-fluid intelligence ), performance was similar regardless if students used differential-associative processing or example elaboration (Experiment 3). Taken as a whole, these results suggest that differential-associative processing is better than example elaboration for learning definitions of related concepts and is as good as example elaboration for learning definitions of unrelated concepts.

Zero-gravity cloud physics laboratory: Experiment program definition and preliminary laboratory concept studies

Science.gov (United States)

Eaton, L. R.; Greco, E. V.

1973-01-01

The experiment program definition and preliminary laboratory concept studies on the zero G cloud physics laboratory are reported. This program involves the definition and development of an atmospheric cloud physics laboratory and the selection and delineations of a set of candidate experiments that must utilize the unique environment of zero gravity or near zero gravity.

Quality evaluation of radiotherapy treatment planning using 3-dimensional CT images

International Nuclear Information System (INIS)

Araki, Yutaka; Isobe, Yoshihide; Ozaki, Shin; Hosoki, Takuya; Mori, Shigeru; Ikeda, Hiroshi.

1984-01-01

Recently superimposition of dose distribution onto CT images has become available with the use of planning computers. However, the distribution is mostly along the plane of central axis of the beam, and evaluation of the quality of planning has not yet been established. In this paper, a method to evaluate the quality is demonstrated, using the extended definitions of ICRU 29 concept in to 3-dimensions. Therapeutic efficiency (Target Volume dose/Treatment Volume dose) is the main key to evaluate it. Concept and procedures are described in detail with two case examples. (author)

[Alcoholism: definition, diagnosis, illness concept, follow-up, results and costs of treatment].

Science.gov (United States)

Feuerlein, W

1991-02-01

The article starts with a review on the definition of alcoholism stressing the useful differentiation between alcohol abuse and alcohol dependence. On the basis of this definition the principles of the diagnosis of alcoholism are demonstrated. The disease concept of alcoholism is discussed in detail. Then the aims, the structure and the results of the therapy for alcoholics are briefly described. The article concludes with a short cost-benefit analysis of the alcoholism treatment.

Concept definition of KT-2, a large-aspect-ratio diverter tokamak with FWCD

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Kyoo; Chang, In Soon; Chung, Moon Kyoo; Hwang, Chul Kyoo; Lee, Kwang Won; In, Sang Ryul; Choi, Byung Ho; Hong, Bong Keun; Oh, Byung Hoon; Chung, Seung Ho; Yoon, Byung Joo; Yoon, Jae Sung; Song, Woo Sub [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Chang, Choong Suk; Chang, Hong Yung; Choi, Duk In; Nam, Chang Heui [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of); Chung, Kyoo Sun [Hanyang Univ., Seoul (Korea, Republic of); Hong, Sang Heui [Seoul National Univ., Seoul (Korea, Republic of); Kang, Heui Dong [Kyungpook National Univ., Taegu (Korea, Republic of); Lee, Jae Koo [Pohang Inst. of Science and Technology, Kyungnam (Korea, Republic of)

1994-11-01

A concept definition of the KT-2 tokamak is made. The research goal of the machine is to study the `advanced tokamak` physics and engineering issues on the mid size large-aspect-ratio diverter tokamak with intense RF heating (>5 MW). Survey of the status of the research fields, the physics basis for the concept, operation scenarios, as well as machine design concept are presented. (Author) 86 refs., 17 figs., 22 tabs.

Concept definition of KT-2, a large-aspect-ratio diverter tokamak with FWCD

International Nuclear Information System (INIS)

Kim, Sung Kyoo; Chang, In Soon; Chung, Moon Kyoo; Hwang, Chul Kyoo; Lee, Kwang Won; In, Sang Ryul; Choi, Byung Ho; Hong, Bong Keun; Oh, Byung Hoon; Chung, Seung Ho; Yoon, Byung Joo; Yoon, Jae Sung; Song, Woo Sub; Chang, Choong Suk; Chang, Hong Yung; Choi, Duk In; Nam, Chang Heui; Chung, Kyoo Sun; Hong, Sang Heui; Kang, Heui Dong; Lee, Jae Koo

1994-11-01

A concept definition of the KT-2 tokamak is made. The research goal of the machine is to study the 'advanced tokamak' physics and engineering issues on the mid size large-aspect-ratio diverter tokamak with intense RF heating (>5 MW). Survey of the status of the research fields, the physics basis for the concept, operation scenarios, as well as machine design concept are presented. (Author) 86 refs., 17 figs., 22 tabs

On the definition of a theoretical concept of an operating system

NARCIS (Netherlands)

Bergstra, J.A.; Middelburg, C.A.

2010-01-01

We dwell on how a definition of a theoretical concept of an operating system, suitable to be incorporated in a mathematical theory of operating systems, could look like. This is considered a valuable preparation for the development of a mathematical theory of operating systems.

MO-E-17A-06: Organ Dose in Abdomen-Pelvis CT: Does TG 111 Equilibrium Dose Concept Better Accounts for KVp Dependence Than Conventional CTDI?

International Nuclear Information System (INIS)

Li, X; Morgan, A; Davros, W; Dong, F; Primak, A; Segars, W

2014-01-01

Purpose: In CT imaging, a desirable quality assurance (QA) dose quantity should account for the dose variability across scan parameters and scanner models. Recently, AAPM TG 111 proposed to use equilibrium dose-pitch product, in place of CT dose index (CTDI100), for scan modes involving table translation. The purpose of this work is to investigate whether this new concept better accounts for the kVp dependence of organ dose than the conventional CTDI concept. Methods: The adult reference female extended cardiac-torso (XCAT) phantom was used for this study. A Monte Carlo program developed and validated for a 128-slice CT system (Definition Flash, Siemens Healthcare) was used to simulate organ dose for abdomenpelvis scans at five tube voltages (70, 80, 100, 120, 140 kVp) with a pitch of 0.8 and a detector configuration of 2x64x0.6 mm. The same Monte Carlo program was used to simulate CTDI100 and equilibrium dose-pitch product. For both metrics, the central and peripheral values were used together with helical pitch to calculate a volume-weighted average, i.e., CTDIvol and (Deq)vol, respectively. Results: While other scan parameters were kept constant, organ dose depended strongly on kVp; the coefficient of variation (COV) across the five kVp values ranged between 70–75% for liver, spleen, stomach, pancreas, kidneys, colon, small intestine, bladder, and ovaries, all of which were inside the primary radiation beam. One-way analysis of variance (ANOVA) for the effect of kVp was highly significant (p=3e−30). When organ dose was normalized by CTDIvol, the COV across the five kVp values reduced to 7–16%. The effect of kVp was still highly significant (p=4e−4). When organ dose was normalized by (Deq)vol, the COV further reduced to 4−12%. The effect of kVp was borderline significant (p=0.04). Conclusion: In abdomen-pelvis CT, TG 111 equilibrium dose concept better accounts for kVp dependence than the conventional CTDI. This work is supported by a faculty startup

MO-E-17A-06: Organ Dose in Abdomen-Pelvis CT: Does TG 111 Equilibrium Dose Concept Better Accounts for KVp Dependence Than Conventional CTDI?

Energy Technology Data Exchange (ETDEWEB)

Li, X [Cleveland State University, Cleveland, OH (United States); Morgan, A; Davros, W [Cleveland State University, Cleveland, OH (United States); Cleveland Clinic, Cleveland, Ohio (United States); Dong, F [Cleveland Clinic, Cleveland, Ohio (United States); Primak, A [Siemens Medical Solutions USA, Inc. (United States); Segars, W [Duke University, Durham, NC (United States)

2014-06-15

Purpose: In CT imaging, a desirable quality assurance (QA) dose quantity should account for the dose variability across scan parameters and scanner models. Recently, AAPM TG 111 proposed to use equilibrium dose-pitch product, in place of CT dose index (CTDI100), for scan modes involving table translation. The purpose of this work is to investigate whether this new concept better accounts for the kVp dependence of organ dose than the conventional CTDI concept. Methods: The adult reference female extended cardiac-torso (XCAT) phantom was used for this study. A Monte Carlo program developed and validated for a 128-slice CT system (Definition Flash, Siemens Healthcare) was used to simulate organ dose for abdomenpelvis scans at five tube voltages (70, 80, 100, 120, 140 kVp) with a pitch of 0.8 and a detector configuration of 2x64x0.6 mm. The same Monte Carlo program was used to simulate CTDI100 and equilibrium dose-pitch product. For both metrics, the central and peripheral values were used together with helical pitch to calculate a volume-weighted average, i.e., CTDIvol and (Deq)vol, respectively. Results: While other scan parameters were kept constant, organ dose depended strongly on kVp; the coefficient of variation (COV) across the five kVp values ranged between 70–75% for liver, spleen, stomach, pancreas, kidneys, colon, small intestine, bladder, and ovaries, all of which were inside the primary radiation beam. One-way analysis of variance (ANOVA) for the effect of kVp was highly significant (p=3e−30). When organ dose was normalized by CTDIvol, the COV across the five kVp values reduced to 7–16%. The effect of kVp was still highly significant (p=4e−4). When organ dose was normalized by (Deq)vol, the COV further reduced to 4−12%. The effect of kVp was borderline significant (p=0.04). Conclusion: In abdomen-pelvis CT, TG 111 equilibrium dose concept better accounts for kVp dependence than the conventional CTDI. This work is supported by a faculty startup

Space station high gain antenna concept definition and technology development

Science.gov (United States)

Wade, W. D.

1972-01-01

The layout of a technology base is reported from which a mechanically gimballed, directional antenna can be developed to support a manned space station proposed for the late 1970's. The effort includes the concept definition for the antenna assembly, an evaluation of available technology, the design of critical subassemblies and the design of critical subassembly tests.

An Investigation of K-8 Preservice Teachers' Concept Images and Mathematical Definitions of Polygons

Science.gov (United States)

Ward, Robin A.

2004-01-01

In this paper, the author presents a study which explored K-8 preservice teachers' concept images and mathematical definitions of polygons. This study was carried out in which K-8 teacher candidates enrolled in an elementary mathematics content course were asked to sort, identify, and provide definitions of such shapes including triangles,…

Definition and Evaluation of Bus and Truck Automation Operations Concepts: Final Report

OpenAIRE

Taso, H. S. Jacob; Botha, Jan L.

2003-01-01

Traffic congestion will continue to worsen and likely worsen at a faster rate than ever. People throughput and freight throughput have become critical issues for California and the rest of the nation. PATH has funded a research project entitled Definition And Evaluation of Bus And Truck Automation Operations Concepts, proposed by the authors. This report summarizes the major findings of the research project. During the one-year project, we reviewed literature and developed operating concepts ...

Definitions of Physical Concepts: A Study of Physics Teachers' Knowledge and Views. Research Report

Science.gov (United States)

Galili, Igal; Lehavi, Yaron

2006-01-01

A study was made of the ability of a population of high-school physics teachers to define physics concepts and of their views regarding the importance of such definitions. It was found possible to arrange the definitions accumulated in categories, and the classification so obtained was consonant with that of the philosophy of science. Although the…

An Analysis of Perceptions and Attitudes Toward the Concepts "Disabled" and "Handicapped" and the Effects of Pre-Structured Definition Upon the Concepts.

Science.gov (United States)

Ianacone, Robert N.; Stodden, Robert A.

The semantic differential technique was used in a study involving 40 undergraduate trainees in the area of special education to analyze the concepts "disabled" and "handicapped" and the effects of structured knowledge or definition on the participants' perceptions of and attitudes toward the concepts. The Semantic differential consisted of bipolar…

Compendium of Executive Summaries from the Maglev System Concept Definition. Final Reports.

Science.gov (United States)

1993-03-01

This report contains the Executive Summaries from the four System Concept Definition (SCD) studies awarded under the National Maglev Initiative...These summaries present the technical feasibility, performance, capital, operating and maintenance costs for a maglev system that would be available by

Formal representation of complex SNOMED CT expressions

Directory of Open Access Journals (Sweden)

Markó Kornél

2008-10-01

Full Text Available Abstract Background Definitory expressions about clinical procedures, findings and diseases constitute a major benefit of a formally founded clinical reference terminology which is ontologically sound and suited for formal reasoning. SNOMED CT claims to support formal reasoning by description-logic based concept definitions. Methods On the basis of formal ontology criteria we analyze complex SNOMED CT concepts, such as "Concussion of Brain with(out Loss of Consciousness", using alternatively full first order logics and the description logic ℰℒ MathType@MTEF@5@5@+=feaagaart1ev2aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaWenfgDOvwBHrxAJfwnHbqeg0uy0HwzTfgDPnwy1aaceaGae8hmHuKae8NeHWeaaa@37B1@. Results Typical complex SNOMED CT concepts, including negations or not, can be expressed in full first-order logics. Negations cannot be properly expressed in the description logic ℰℒ MathType@MTEF@5@5@+=feaagaart1ev2aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGaciGaaiaabeqaaeqabiWaaaGcbaWenfgDOvwBHrxAJfwnHbqeg0uy0HwzTfgDPnwy1aaceaGae8hmHuKae8NeHWeaaa@37B1@ underlying SNOMED CT. All concepts concepts the meaning of which implies a temporal scope may be subject to diverging interpretations, which are often unclear in SNOMED CT as their contextual determinants are not made explicit. Conclusion The description of complex medical occurrents is ambiguous, as the same situations can be described as (i a complex occurrent C that has A and B as temporal parts, (ii a simple occurrent A' defined as a kind of A followed by some B, or (iii a simple occurrent B' defined as a kind of B preceded by some A. As negative statements in SNOMED CT cannot be exactly represented without

On the Concept and Definition of Terrorism Risk.

Science.gov (United States)

Aven, Terje; Guikema, Seth

2015-12-01

In this article, we provide some reflections on how to define and understand the concept of terrorism risk in a professional risk assessment context. As a basis for this discussion we introduce a set of criteria that we believe should apply to any conceptualization of terrorism risk. These criteria are based on both criteria used in other areas of risk analysis and our experience with terrorism risk analysis. That is, these criteria offer our perspective. We show that several of the suggested perspectives and definitions have weaknesses in relation to these criteria. A main problem identified is the idea that terrorism risk can be conceptualized as a function of probability and consequence, not as a function of the interactions between adaptive individuals and organizations. We argue that perspectives based solely on probability and consequence should be used cautiously or not at all because they fail to reflect the essential features of the concept of terrorism risk, the threats and attacks, their consequences, and the uncertainties, all in the context of adaptation by the adversaries. These three elements should in our view constitute the main pillars of the terrorism risk concept. From this concept we can develop methods for assessing the risk by identifying a set of threats, attacks, and consequence measures associated with the possible outcome scenarios together with a description of the uncertainties and interactions between the adversaries. © 2015 Society for Risk Analysis.

(18)F-FDG PET-CT simulation for non-small-cell lung cancer: effect in patients already staged by PET-CT.

Science.gov (United States)

Hanna, Gerard G; McAleese, Jonathan; Carson, Kathryn J; Stewart, David P; Cosgrove, Vivian P; Eakin, Ruth L; Zatari, Ashraf; Lynch, Tom; Jarritt, Peter H; Young, V A Linda; O'Sullivan, Joe M; Hounsell, Alan R

2010-05-01

Positron emission tomography (PET), in addition to computed tomography (CT), has an effect in target volume definition for radical radiotherapy (RT) for non-small-cell lung cancer (NSCLC). In previously PET-CT staged patients with NSCLC, we assessed the effect of using an additional planning PET-CT scan for gross tumor volume (GTV) definition. A total of 28 patients with Stage IA-IIIB NSCLC were enrolled. All patients had undergone staging PET-CT to ensure suitability for radical RT. Of the 28 patients, 14 received induction chemotherapy. In place of a RT planning CT scan, patients underwent scanning on a PET-CT scanner. In a virtual planning study, four oncologists independently delineated the GTV on the CT scan alone and then on the PET-CT scan. Intraobserver and interobserver variability were assessed using the concordance index (CI), and the results were compared using the Wilcoxon signed ranks test. PET-CT improved the CI between observers when defining the GTV using the PET-CT images compared with using CT alone for matched cases (median CI, 0.57 for CT and 0.64 for PET-CT, p = .032). The median of the mean percentage of volume change from GTV(CT) to GTV(FUSED) was -5.21% for the induction chemotherapy group and 18.88% for the RT-alone group. Using the Mann-Whitney U test, this was significantly different (p = .001). PET-CT RT planning scan, in addition to a staging PET-CT scan, reduces interobserver variability in GTV definition for NSCLC. The GTV size with PET-CT compared with CT in the RT-alone group increased and was reduced in the induction chemotherapy group.

18F-FDG PET-CT Simulation for Non-Small-Cell Lung Cancer: Effect in Patients Already Staged by PET-CT

International Nuclear Information System (INIS)

Hanna, Gerard G.; McAleese, Jonathan; Carson, Kathryn J.; Stewart, David P.; Cosgrove, Vivian P.; Eakin, Ruth L.; Zatari, Ashraf; Lynch, Tom; Jarritt, Peter H.; Young, V.A. Linda D.C.R.; O'Sullivan, Joe M.

2010-01-01

Purpose: Positron emission tomography (PET), in addition to computed tomography (CT), has an effect in target volume definition for radical radiotherapy (RT) for non-small-cell lung cancer (NSCLC). In previously PET-CT staged patients with NSCLC, we assessed the effect of using an additional planning PET-CT scan for gross tumor volume (GTV) definition. Methods and Materials: A total of 28 patients with Stage IA-IIIB NSCLC were enrolled. All patients had undergone staging PET-CT to ensure suitability for radical RT. Of the 28 patients, 14 received induction chemotherapy. In place of a RT planning CT scan, patients underwent scanning on a PET-CT scanner. In a virtual planning study, four oncologists independently delineated the GTV on the CT scan alone and then on the PET-CT scan. Intraobserver and interobserver variability were assessed using the concordance index (CI), and the results were compared using the Wilcoxon signed ranks test. Results: PET-CT improved the CI between observers when defining the GTV using the PET-CT images compared with using CT alone for matched cases (median CI, 0.57 for CT and 0.64 for PET-CT, p = .032). The median of the mean percentage of volume change from GTV CT to GTV FUSED was -5.21% for the induction chemotherapy group and 18.88% for the RT-alone group. Using the Mann-Whitney U test, this was significantly different (p = .001). Conclusion: PET-CT RT planning scan, in addition to a staging PET-CT scan, reduces interobserver variability in GTV definition for NSCLC. The GTV size with PET-CT compared with CT in the RT-alone group increased and was reduced in the induction chemotherapy group.

Mars power system concept definition study. Volume 1: Study results

Science.gov (United States)

Littman, Franklin D.

1994-01-01

A preliminary top level study was completed to define power system concepts applicable to Mars surface applications. This effort included definition of power system requirements and selection of power systems with the potential for high commonality. These power systems included dynamic isotope, Proton Exchange Membrane (PEM) regenerative fuel cell, sodium sulfur battery, photovoltaic, and reactor concepts. Design influencing factors were identified. Characterization studies were then done for each concept to determine system performance, size/volume, and mass. Operations studies were done to determine emplacement/deployment maintenance/servicing, and startup/shutdown requirements. Technology development roadmaps were written for each candidate power system (included in Volume 2). Example power system architectures were defined and compared on a mass basis. The dynamic isotope power system and nuclear reactor power system architectures had significantly lower total masses than the photovoltaic system architectures. Integrated development and deployment time phasing plans were completed for an example DIPS and reactor architecture option to determine the development strategies required to meet the mission scenario requirements.

PET/CT and vascular disease: Current concepts

Energy Technology Data Exchange (ETDEWEB)

Cavalcanti Filho, Jose Leite Gondim; Souza Leao Lima, Ronaldo de [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Department of Radiology, Rio de Janeiro Federal University (UFRJ), Rio de Janeiro (Brazil); Souza Machado Neto, Luiz de [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Kayat Bittencourt, Leonardo, E-mail: lkayat@terra.com.br [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Department of Radiology, Rio de Janeiro Federal University (UFRJ), Rio de Janeiro (Brazil); Cortes Domingues, Romeu [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Fonseca, Lea Mirian Barbosa da [CDPI and Multi-Imagem Clinics, Rio de Janeiro (Brazil); Department of Radiology, Rio de Janeiro Federal University (UFRJ), Rio de Janeiro (Brazil)

2011-10-15

Since its introduction in 2001, positron emission tomography associated to computed tomography (PET/CT) has been established as a standard tool in cancer evaluation. Being a multimodality imaging method, it combines in a single session the sensitivity granted by PET for detection of molecular targets within the picomolar range, with an underlying submilimetric resolution inherent to CT, that can precisely localize the PET findings. In this last decade, there have been new insights regarding the pathophysiology of atherosclerosis, particularly about plaque rupture and vascular remodeling. This has increased the interest for research on PET/CT in vascular diseases as a potential new diagnostic tool, since some PET molecular targets could identify diseases before the manifestation of gross anatomic features. In this review, we will describe the current applications of PET/CT in vascular diseases, emphasizing its usefulness in the settings of vasculitis, aneurysms, vascular graft infection, aortic dissection, and atherosclerosis/plaque vulnerability. Although not being properly peripheral vascular conditions, ischemic cardiovascular disease and cerebrovascular disease will be briefly addressed as well, due to their widespread prevalence and importance.

Definition and Evaluation of Bus and Truck Automation Operations Concepts

OpenAIRE

Tsao, H.-S. Jacob; Botha, Jan L.

2002-01-01

Traffic congestion will continue to worsen and likely worsen at a faster rate than ever. People throughput and freight throughput have become critical issues for California and the rest of the nation. PATH has been funding a one-year research project entitled "Definition and Evaluation of Bus and Truck Automation Operations Concepts," proposed by the authors. This report summarizes the results of the research project achieved during the first six months. During those six months, we reviewed l...

A DEFINITION OF AUTHENTICITY CONCEPT IN CONSERVATION OF CULTURAL LANDSCAPES

Directory of Open Access Journals (Sweden)

Somayeh Fadaei Nezhad

2015-03-01

Full Text Available Cultural landscape can be defined as the result of human interaction with nature over time, which has led to the formation of the many and diverse layers of value. Currently, the UNESCO World Heritage Centre has a unique role among other scientific associations. In recent years, the World Heritage Center has put efforts into developing a framework and measures for evaluation and management of cultural landscapes. Moreover, the concept of authenticity; as the transmitter of values and significance of cultural landscape, is considered as the key component in the process of cultural landscape conservation. A lot of scientific resources have pointed out the importance of authenticity in the process of conserving cultural landscapes. However, the role of authenticity within the domain of conservation of cultural landscapes has received little attention. One of the main reasons can be lack of adaptation between conventional definitions of UNESCO and international documents concerning the authenticity for including the flexible and dynamic structure of cultural landscapes around the world. Therefore, this paper seeks to explore and develop a flexible framework in order to redefine the concept of authenticity in relation to cultural landscapes, which has some overlaps with UNESCO definitions despite its differences. For developing this framework, Iranian-Islamic philosophy of Mollasadra is applied and described with some examples of cultural landscapes in Iran.

The significance of a uniform definition of pathological lymph nodes in Hodgkin lymphoma: Impact of different thresholds for positive lymph nodes in CT imaging on staging and therapy

International Nuclear Information System (INIS)

Vorwerk, Hilke; Obenauer, Silvia; Schmidberger, Heinz; Hess, Clemens F.; Weiss, Elisabeth

2008-01-01

Background and Purpose: The most commonly used approach for the assessment for differentiating malignant versus reactive lymph nodes is the measurement of the cross-section diameter of the lymph nodes in the transversal CT-planes. The intention of this article is to assess the impact of varying definitions of pathological lymph node size in CT-imaging in patients with Hodgkin lymphoma and to evaluate its effect on staging, chemotherapy regimes and radiation field size. Materials and methods: Pretherapeutic CT-scans of 10 consecutive patients with Hodgkin lymphoma have been evaluated based on two different definitions for malignant lymph node size; the classification of the German study group for Hodgkin lymphoma (1.0 cm) and the classification according to the results of the Cotswold consensus meeting 1989 (1.5 cm). Results: Applying the definitions of the DHSG and the Cotswold meeting we found more affected lymph node regions compared to the evaluation of the referring institutions in 9/10 and 6/10 patients, higher stages in 2/10 and 1/10 patients, more intense chemotherapy regimes in 3/10 and 1/10 and larger radiation fields in 10/10 and 6/10 patients, respectively. Conclusions: Varying definitions of pathologic lymph node size and inconsequent application of definitions reduce the comparability between different studies and within each study

PET/CT and radiotherapy

International Nuclear Information System (INIS)

Messa, C.; CNR, Milano; S. Gerardo Hospital, Monza; Di Muzio, N.; Picchio, M.; Bettinardi, V.; Gilardi, M.C.; CNR, Milano; San Raffaele Scientific Institute, Milano; Fazio, F.; CNR, Milano; San Raffaele Scientific Institute, Milano; San Raffaele Scientific Institute, Milano

2006-01-01

This article reviews the state of the art of PET/CT applications in radiotherapy, specifically its use in disease staging, patient selection, treatment planning and treatment evaluation. Diseases for which radiotherapy with radical intent is indicated will be considered, as well as those in which PET/CT may actually change the course of disease. The methodological and technological aspects of PET/CT in radiotherapy are discussed, focusing on the problem of target volume definition with CT and PET functional imaging and the problem of tumor motion with respect to imaging and dose delivery

68Ga-PSMA PET/CT in Patients with Rising Prostatic-Specific Antigen After Definitive Treatment of Prostate Cancer: Detection Efficacy and Diagnostic accuracy.

Science.gov (United States)

Hamed, Maged Abdel Galil; Basha, Mohammad Abd Alkhalik; Ahmed, Hussien; Obaya, Ahmed Ali; Afifi, Amira Hamed Mohamed; Abdelbary, Eman H

2018-06-20

68 Ga-prostate-specific membrane antigen-11 ( 68 Ga-PSMA-11) is a recently developed positron emission tomography (PET) tracer that can detect prostate cancer (PC) relapses and metastases with high contrast resolution. The aim of this study was to assess the detection efficacy and diagnostic accuracy of 68 Ga-PSMA PET/CT image in patients with rising prostatic-specific antigen (PSA) after treatment of PC. The present prospective study included 188 patients who exhibited rising of PSA level on a routine follow-up examination after definitive treatment of PC. All patients underwent a 68 Ga-PSMA PET/CT examination. For each patient, we determined the disease stage, the Gleason score, and the maximum standardized uptake value of the local recurrence and extraprostatic metastases. The detection efficacy and diagnostic accuracy of 68 Ga-PSMA PET/CT were established by histopathology and clinical and imaging follow-up as the reference standards. 68 Ga-PSMA PET/CT detected tumour relapse in 165 patients (35 patients had local recurrence, 106 patients had extraprostatic metastases, and 24 patients had combined lesions). The sensitivity, specificity, and accuracy values of 68 Ga-PSMA PET/CT examination in the detection of PC recurrence were 98.8%, 100%, and 98.8%, respectively. 68 Ga-PSMA PET/CT revealed an overall detection rate of 87.8% (165/188) in patients with rising PSA (median of 2.2 ng/mL, and range of 0.01-70 ng/mL). 68 Ga-PSMA PET/CT is a valuable tool for the detection of PC local recurrence or extraprostatic metastases following rising PSA levels after primary definitive therapy and should be incorporated during routine work-up. Copyright © 2018. Published by Elsevier Inc.

A Teacher's Conception of Definition and Use of Examples When Doing and Teaching Mathematics

Science.gov (United States)

Johnson, Heather Lynn; Blume, Glendon W.; Shimizu, Jeanne K.; Graysay, Duane; Konnova, Svetlana

2014-01-01

To contribute to an understanding of the nature of teachers' mathematical knowledge and its role in teaching, the case study reported in this article investigated a teacher's conception of a metamathematical concept, definition, and her use of examples in doing and teaching mathematics. Using an enactivist perspective on mathematical…

Zero-gravity cloud physics laboratory: Candidate experiments definition and preliminary concept studies

Science.gov (United States)

Eaton, L. R.; Greco, R. V.; Hollinden, A. B.

1973-01-01

The candidate definition studies on the zero-g cloud physics laboratory are covered. This laboratory will be an independent self-contained shuttle sortie payload. Several critical technology areas have been identified and studied to assure proper consideration in terms of engineering requirements for the final design. Areas include chambers, gas and particle generators, environmental controls, motion controls, change controls, observational techniques, and composition controls. This unique laboratory will allow studies to be performed without mechanical, aerodynamics, electrical, or other type techniques to support the object under study. This report also covers the candidate experiment definitions, chambers and experiment classes, laboratory concepts and plans, special supporting studies, early flight opportunities and payload planning data for overall shuttle payload requirements assessments.

Measuring social science concepts in pharmacy education research: From definition to item analysis of self-report instruments.

Science.gov (United States)

Cor, M Ken

Interpreting results from quantitative research can be difficult when measures of concepts are constructed poorly, something that can limit measurement validity. Social science steps for defining concepts, guidelines for limiting construct-irrelevant variance when writing self-report questions, and techniques for conducting basic item analysis are reviewed to inform the design of instruments to measure social science concepts in pharmacy education research. Based on a review of the literature, four main recommendations emerge: These include: (1) employ a systematic process of conceptualization to derive nominal definitions; (2) write exact and detailed operational definitions for each concept, (3) when creating self-report questionnaires, write statements and select scales to avoid introducing construct-irrelevant variance (CIV); and (4) use basic item analysis results to inform instrument revision. Employing recommendations that emerge from this review will strengthen arguments to support measurement validity which in turn will support the defensibility of study finding interpretations. An example from pharmacy education research is used to contextualize the concepts introduced. Copyright © 2017 Elsevier Inc. All rights reserved.

A semantic-based method for extracting concept definitions from scientific publications: evaluation in the autism phenotype domain.

Science.gov (United States)

Hassanpour, Saeed; O'Connor, Martin J; Das, Amar K

2013-08-12

A variety of informatics approaches have been developed that use information retrieval, NLP and text-mining techniques to identify biomedical concepts and relations within scientific publications or their sentences. These approaches have not typically addressed the challenge of extracting more complex knowledge such as biomedical definitions. In our efforts to facilitate knowledge acquisition of rule-based definitions of autism phenotypes, we have developed a novel semantic-based text-mining approach that can automatically identify such definitions within text. Using an existing knowledge base of 156 autism phenotype definitions and an annotated corpus of 26 source articles containing such definitions, we evaluated and compared the average rank of correctly identified rule definition or corresponding rule template using both our semantic-based approach and a standard term-based approach. We examined three separate scenarios: (1) the snippet of text contained a definition already in the knowledge base; (2) the snippet contained an alternative definition for a concept in the knowledge base; and (3) the snippet contained a definition not in the knowledge base. Our semantic-based approach had a higher average rank than the term-based approach for each of the three scenarios (scenario 1: 3.8 vs. 5.0; scenario 2: 2.8 vs. 4.9; and scenario 3: 4.5 vs. 6.2), with each comparison significant at the p-value of 0.05 using the Wilcoxon signed-rank test. Our work shows that leveraging existing domain knowledge in the information extraction of biomedical definitions significantly improves the correct identification of such knowledge within sentences. Our method can thus help researchers rapidly acquire knowledge about biomedical definitions that are specified and evolving within an ever-growing corpus of scientific publications.

Evaluation of a dual-room sliding gantry CT concept for workflow optimisation in polytrauma and regular in- and outpatient management

Energy Technology Data Exchange (ETDEWEB)

Frellesen, Claudia; Boettcher, Marie; Wichmann, Julian L.; Drieske, Martina; Kerl, J. Matthias; Lehnert, Thomas [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt (Germany); Nau, Christoph; Geiger, Emmanuel; Wutzler, Sebastian [Department of Trauma, Reconstructive and Hand Surgery, Clinic of the Goethe University, Frankfurt (Germany); Ackermann, Hanns [Department of Biostatistics and Mathematical Modelling, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Vogl, Thomas J. [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt (Germany); Bauer, Ralf W., E-mail: ralfwbauer@aol.com [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt (Germany)

2015-01-15

Highlights: • A sliding gantry trauma room CT solution facilitates significantly faster polytrauma management. • Faster and more efficient resumption of regularly scheduled patients due to a two room solution is supported. • Sliding gantry CT achieves the same patient throughput as two separate conventional CT devices. - Abstract: Objectives: To reveal the impact on workflow from introducing a dual-room sliding gantry CT to the trauma room for polytrauma and regularly scheduled in- outpatients with regard to efficiency and degree of capacity utilisation. Materials and methods: Time analysis was performed for 30 polytrauma patients each in 2 different trauma room settings, the new trauma room comprising a sliding gantry CT, the old one a stationary single-room CT. Complete trauma room and diagnostic workup times were manually measured and compared for both groups. In a third scenario, the number of CT scans performed with one single sliding gantry CT and the two-room concept was compared to the number of CT scans performed on two separate regular CT units in a 5 days clinical routine sample. Results: Patients demographics and type of CT examinations were comparable for all patient groups. The median time from patient arrival in the trauma room until beginning of CT scanning was 6 min shorter for the sliding gantry CT group (21 vs.15 min). Sliding gantry CT embedded in a two-room solution achieved 252 CT scans in 5 working days, compared to 250 CT scans on two separate regular CT units with the same man power. Conclusions: Sliding gantry CT in the trauma room allows for significant time saving in the diagnostic workup of polytrauma patients and faster resumption of the regular in- outpatient's CT schedule is possible. With the same man power, the dual-room solution is able to generate the same throughput as two separate CT units.

Evaluation of a dual-room sliding gantry CT concept for workflow optimisation in polytrauma and regular in- and outpatient management

International Nuclear Information System (INIS)

Frellesen, Claudia; Boettcher, Marie; Wichmann, Julian L.; Drieske, Martina; Kerl, J. Matthias; Lehnert, Thomas; Nau, Christoph; Geiger, Emmanuel; Wutzler, Sebastian; Ackermann, Hanns; Vogl, Thomas J.; Bauer, Ralf W.

2015-01-01

Highlights: • A sliding gantry trauma room CT solution facilitates significantly faster polytrauma management. • Faster and more efficient resumption of regularly scheduled patients due to a two room solution is supported. • Sliding gantry CT achieves the same patient throughput as two separate conventional CT devices. - Abstract: Objectives: To reveal the impact on workflow from introducing a dual-room sliding gantry CT to the trauma room for polytrauma and regularly scheduled in- outpatients with regard to efficiency and degree of capacity utilisation. Materials and methods: Time analysis was performed for 30 polytrauma patients each in 2 different trauma room settings, the new trauma room comprising a sliding gantry CT, the old one a stationary single-room CT. Complete trauma room and diagnostic workup times were manually measured and compared for both groups. In a third scenario, the number of CT scans performed with one single sliding gantry CT and the two-room concept was compared to the number of CT scans performed on two separate regular CT units in a 5 days clinical routine sample. Results: Patients demographics and type of CT examinations were comparable for all patient groups. The median time from patient arrival in the trauma room until beginning of CT scanning was 6 min shorter for the sliding gantry CT group (21 vs.15 min). Sliding gantry CT embedded in a two-room solution achieved 252 CT scans in 5 working days, compared to 250 CT scans on two separate regular CT units with the same man power. Conclusions: Sliding gantry CT in the trauma room allows for significant time saving in the diagnostic workup of polytrauma patients and faster resumption of the regular in- outpatient's CT schedule is possible. With the same man power, the dual-room solution is able to generate the same throughput as two separate CT units

Multisource inverse-geometry CT. Part I. System concept and development

Energy Technology Data Exchange (ETDEWEB)

De Man, Bruno, E-mail: deman@ge.com; Harrison, Dan; Yin, Zhye [CT Systems and Applications Laboratory, GE Global Research, Niskayuna, New York 12309 (United States); Uribe, Jorge [Functional Imaging Laboratory, GE Global Research, Niskayuna, New York 12309 (United States); Baek, Jongduk [School of Integrated Technology, Yonsei University, Incheon 406-840 (Korea, Republic of); Longtin, Randy; Roy, Jaydeep; Frutschy, Kristopher [Mechanical Systems Technologies, GE Global Research, Niskayuna, New York 12309 (United States); Waters, Bill [Design and Development Shops, GE Global Research, Niskayuna, New York 12309 (United States); Wilson, Colin; Inzinna, Lou; Neculaes, V. Bogdan [High Energy Physics Laboratory, GE Global Research, Niskayuna, New York 12309 (United States); Short, Jonathan [Detector Laboratory, GE Global Research, Niskayuna, New York 12309 (United States); Reynolds, Joseph [High Frequency Power Electronics Laboratory, GE Global Research, Niskayuna, New York 12309 (United States); Senzig, Bob [Molecular Imaging and Computed Tomography, GE Healthcare, Waukesha, Wisconsin 53188 (United States); Pelc, Norbert [Department of Radiology, Stanford University, Stanford, California 94305 (United States)

2016-08-15

Purpose: This paper presents an overview of multisource inverse-geometry computed tomography (IGCT) as well as the development of a gantry-based research prototype system. The development of the distributed x-ray source is covered in a companion paper [V. B. Neculaes et al., “Multisource inverse-geometry CT. Part II. X-ray source design and prototype,” Med. Phys. 43, 4617–4627 (2016)]. While progress updates of this development have been presented at conferences and in journal papers, this paper is the first comprehensive overview of the multisource inverse-geometry CT concept and prototype. The authors also provide a review of all previous IGCT related publications. Methods: The authors designed and implemented a gantry-based 32-source IGCT scanner with 22 cm field-of-view, 16 cm z-coverage, 1 s rotation time, 1.09 × 1.024 mm detector cell size, as low as 0.4 × 0.8 mm focal spot size and 80–140 kVp x-ray source voltage. The system is built using commercially available CT components and a custom made distributed x-ray source. The authors developed dedicated controls, calibrations, and reconstruction algorithms and evaluated the system performance using phantoms and small animals. Results: The authors performed IGCT system experiments and demonstrated tube current up to 125 mA with up to 32 focal spots. The authors measured a spatial resolution of 13 lp/cm at 5% cutoff. The scatter-to-primary ratio is estimated 62% for a 32 cm water phantom at 140 kVp. The authors scanned several phantoms and small animals. The initial images have relatively high noise due to the low x-ray flux levels but minimal artifacts. Conclusions: IGCT has unique benefits in terms of dose-efficiency and cone-beam artifacts, but comes with challenges in terms of scattered radiation and x-ray flux limits. To the authors’ knowledge, their prototype is the first gantry-based IGCT scanner. The authors summarized the design and implementation of the scanner and the authors presented

Converting from CT- to MRI-only-based target definition in radiotherapy of localized prostate cancer: A comparison between two modalities.

Science.gov (United States)

Seppälä, Tiina; Visapää, Harri; Collan, Juhani; Kapanen, Mika; Beule, Annette; Kouri, Mauri; Tenhunen, Mikko; Saarilahti, Kauko

2015-11-01

To investigate the conversion of prostate cancer radiotherapy (RT) target definition from CT-based planning into an MRI-only-based planning procedure. Using the CT- and MRI-only-based RT planning protocols, 30 prostate cancer patients were imaged in the RT fixation position. Two physicians delineated the prostate in both CT and T2-weighted MRI images. The CT and MRI images were coregistered based on gold seeds and anatomic borders of the prostate. The uncertainty of the coregistration, as well as differences in target volumes and uncertainty of contour delineation were investigated. Conversion of margins and dose constraints from CT- to MRI-only-based treatment planning was assessed. On average, the uncertainty of image coregistration was 0.4 ± 0.5 mm (one standard deviation, SD), 0.9 ± 0.8 mm and 0.9 ± 0.9 mm in the lateral, anterior-posterior and base-apex direction, respectively. The average ratio of the prostate volume between CT and MRI was 1.20 ± 0.15 (one SD). Compared to the CT-based contours, the MRI-based contours were on average 2-7 mm smaller in the apex, 0-1 mm smaller in the rectal direction and 1-4 mm smaller elsewhere. When converting from a CT-based planning procedure to an MRI-based one, the overall planning target volumes (PTV) are prominently reduced only in the apex. The prostate margins and dose constraints can be retained by this conversion.

CT findings of inoperable lung carcinoma

International Nuclear Information System (INIS)

Gay, S.B.; Black, W.C.

1987-01-01

CT is useful in the evaluation of patients with newly diagnosed or highly suspected lung cancer. The principal role of CT is to screen those patients with metastatic disease beyond the hili from an attempt at curative thoracotomy. While CT is regarded as very sensitive, it is not considered highly specific, and thus a surgical procedure is usually recommended for definitive diagnosis of most ''positive'' CT findings. However, the authors demonstrate a few characteristic CT findings that are highly predictive of unresectable metastatic disease. These CT findings include massive mediastinal lymphadenopathy, diffuse mediastinal infiltration, pericardial involvement, vascular encasement, and advanced chest wall invasion

Indeterminate lesions on planar bone scintigraphy in lung cancer patients: SPECT, CT or SPECT-CT?

International Nuclear Information System (INIS)

Sharma, Punit; Kumar, Rakesh; Singh, Harmandeep; Bal, Chandrasekhar; Malhotra, Arun; Julka, Pramod Kumar; Thulkar, Sanjay

2012-01-01

The objective of the present study was to compare the role of single photon emission computed tomography (SPECT), computed tomography (CT) and SPECT-CT of selected volume in lung cancer patients with indeterminate lesions on planar bone scintigraphy (BS). The data of 50 lung cancer patients (53 ± 10.3 years; range 30-75; male/female 38/12) with 65 indeterminate lesions on planar BS (January 2010 to November 2010) were retrospectively evaluated. All of them underwent SPECT-CT of a selected volume. SPECT, CT and SPECT-CT images were independently evaluated by two experienced readers (experience in musculoskeletal imaging, including CT: 5 and 7 years) in separate sessions. A scoring scale of 1 to 5 was used, in which 1 is definitely metastatic, 2 is probably metastatic, 3 is indeterminate, 4 is probably benign and 5 is definitely benign. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for each modality, taking a score ≤2 as metastatic. With receiver operating characteristic (ROC) curve analysis, areas under the curve (AUC) were calculated for each modality and compared. Clinical and imaging follow-up and/or histopathology were taken as reference standard. For both readers SPECT was inferior to CT (P = 0.004, P = 0.022) and SPECT-CT (P = 0.003, P = 0.037). However, no significant difference was found between CT and SPECT-CT for reader 1 (P = 0.847) and reader 2 (P = 0.592). The findings were similar for lytic as well as sclerotic lesions. Moderate inter-observer agreement was seen for SPECT images (κ = 0.426), while almost perfect agreement was seen for CT (κ = 0.834) and SPECT-CT (κ = 0.971). CT alone and SPECT-CT are better than SPECT for accurate characterisation of indeterminate lesions on planar BS in lung cancer patients. CT alone is not inferior to SPECT-CT for this purpose and might be preferred because of shorter acquisition time and wider availability. (orig.)

Do SNOMED CT Relationships Qualify?

NARCIS (Netherlands)

Cornet, Ronald

2008-01-01

An important feature of SNOMED CT is post-coordination, which is enabled as SNOMED CT specifies refinability of target concepts of relationships. In this paper the use of refinable relationships in SNOMED CT is analysed, and the interplay between refinable and defining relationships. Refinability is

Basic Definitions and Concepts of Systems Approach, Mathematical Modeling and Information Technologies in Sports Science

Directory of Open Access Journals (Sweden)

А. Лопатьєв

2017-09-01

Full Text Available The objective is to systematize and adapt the basic definitions and concepts of the systems approach, mathematical modeling and information technologies to sports science. Materials and methods. The research has studied the availability of appropriate terms in shooting sports, which would meet the requirements of modern sports science. It has examined the compliance of the shooting sports training program for children and youth sports schools, the Olympic reserve specialized children and youth schools, schools of higher sports skills, and sports educational institutions with the modern requirements and principles. Research results. The paper suggests the basic definitions adapted to the requirements of technical sports and sports science. The research has thoroughly analyzed the shooting sports training program for children and youth sports schools, the Olympic reserve specialized children and youth schools, schools of higher sports skills, and sports educational institutions. The paper offers options to improve the training program in accordance with the modern tendencies of training athletes.  Conclusions. The research suggests to systematize and adapt the basic definitions and concepts of the systems approach, mathematical modeling and information technologies using the example of technical sports.

The relation of CT-determined tumor parameters and local and regional outcome of tonsillar cancer after definitive radiation treatment

International Nuclear Information System (INIS)

Hermans, Robert; Op de beeck, Katya; Bogaert, Walter van den; Rijnders, Alexis; Staelens, Lorenzo; Feron, Michel; Bellon, Erwin

2001-01-01

Purpose: To investigate the value of CT-derived tumor parameters as predictor of local and regional outcome of tonsillar squamous cell carcinoma treated by definitive radiation therapy. Methods and Materials: The pretreatment CT studies of 112 patients with tonsillar squamous cell carcinoma were reviewed. After redigitizing the films, primary and nodal tumor volume was calculated with the summation-of-areas technique. The nodal CT aspect was graded using a 3-point scale (homogenous, inhomogeneous, and necrotic). Mean follow-up time was 33 months. Actuarial statistical analysis of local and regional outcome was done for each of the covariates; multivariate analysis was performed using Cox's proportional hazards model. Results: In the actuarial analysis, CT-determined primary tumor volume was significantly correlated with local recurrence rate (p<0.05) when all patients were considered, but primary tumor volume did not predict local control within the T2, T3, and T4 category. CT-determined nodal volume was significantly related to regional outcome (p<0.01), but nodal density was not. Total tumor volume was not significantly related to locoregional outcome (p=0.1). In the multivariate analysis, the T and N categories were the independent predictors of local and regional outcomes, respectively. Conclusion: Compared to other head-and-neck sites, primary and nodal tumor volume have only marginal predictive value regarding local and regional outcome after radiation therapy in tonsillar cancer

Exploring Mathematical Definition Construction Processes

Science.gov (United States)

Ouvrier-Buffet, Cecile

2006-01-01

The definition of "definition" cannot be taken for granted. The problem has been treated from various angles in different journals. Among other questions raised on the subject we find: the notions of "concept definition" and "concept image", conceptions of mathematical definitions, redefinitions, and from a more axiomatic point of view, how to…

A simplified CT-based definition of the lymph node levels in the node negative neck

International Nuclear Information System (INIS)

Wijers, O.B.; Levendag, P.C.; Tan, T.; Dieren, E.B. van; Sornsen de Koste, J. van; Est, H. van der; Senan, S.; Nowak, P.J.C.M.

1999-01-01

Using three dimensional (3D) conformal radiotherapy (CRT) techniques for elective neck irradiation (ENI) may allow for local disease control to be maintained while diminishing xerostomia by eliminating major salivary glands (or parts thereof) from the treatment portals. The standardization of CT based target volumes for the clinically negative (elective) neck is a prerequisite for 3DCRT. The aim of the present study was to substantially modify an existing ('original') CT-based protocol for the delineation of the neck tar-et volume, into a more practical ('simplified') protocol. This will allow for rapid contouring and the implementation of conformal ENI in routine clinical procedures. An earlier ('original') version of the CT-based definition for elective neck node re-ions 2-5 was re-evaluated, using 15 planning CT scans of previously treated patients. The contouring guidelines were simplified by (1) using a smaller number of easily identifiable soft tissue- and bony anatomical landmarks, which in turn had to be identified in only a limited number of CT slices, and (2) by subsequently interpolating the contoured lymph node regions. The adequacy of target coverage and the sparing using both 'original' and 'simplified' delineation protocols was evaluated by DVH analysis after contouring the primary tumor, the neck and the major salivary glands in a patient with supraglottic laryngeal (SGL) carcinoma who was treated using a 3DCRT technique. The BEV projections of the 'original' and the 'simplified' versions of the 3D elective neck target showed good agreement and were found to be reproducible. The DVH's of the target and parotid glands were not significantly different using both contouring protocols. The 'simplified' protocol for the delineation of the 3D elective neck target produced both comparable target coverage and sparing of the major salivary glands. When used together with an interpolation program, this 'simplified' protocol substantial reduced the contouring

Terms, concepts and definitions in clinical artificial nutrition. The ConT-SEEN Project.

Science.gov (United States)

Del Olmo García, María Dolores; Ocón Bretón, Julia; Álvarez Hernández, Julia; Ballesteros Pomar, María Dolores; Botella Romero, Francisco; Bretón Lesmes, Irene; de Luis Román, Daniel; Luengo Pérez, Luis Miguel; Martínez Olmos, Miguel Ángel; Olveira Fuster, Gabriel

2018-01-01

Imprecision in terms used in the field of clinical nutrition may lead to misinterpretations among professionals. For this reason, the Spanish Society of Endocrinology and Nutrition (SEEN) promoted this document on the terms and definitions used in clinical artificial nutrition (enteral and parenteral), establishing an agreement between Spanish experts of this specialty. Forty-seven specialists in endocrinology and nutrition, members of the Nutrition Area of the SEEN, participated between April and September 2016. After a systematic literature review, 52 concepts were proposed. The coordinators included two additional concepts, and 57were finally selected by the working group: 13 of a general nature, 30 referring to enteral nutrition and 14 to parenteral nutrition. The degree of agreement was subsequently determined using a two-round Delphi process. It was finally ratified by consistency and concordance analysis. Fifty-four of the 57 terms had a very consistent agreement and were concordant. Only three showed no concordance, of whom two were very consistent and one inconsistent. In conclusion, there was consensus in the definition of 54 basic terms in the practice of clinical nutrition. Copyright © 2017 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.

Using SNOMED CT to represent two interface terminologies.

Science.gov (United States)

Rosenbloom, S Trent; Brown, Steven H; Froehling, David; Bauer, Brent A; Wahner-Roedler, Dietlind L; Gregg, William M; Elkin, Peter L

2009-01-01

Interface terminologies are designed to support interactions between humans and structured medical information. In particular, many interface terminologies have been developed for structured computer based documentation systems. Experts and policy-makers have recommended that interface terminologies be mapped to reference terminologies. The goal of the current study was to evaluate how well the reference terminology SNOMED CT could map to and represent two interface terminologies, MEDCIN and the Categorical Health Information Structured Lexicon (CHISL). Automated mappings between SNOMED CT and 500 terms from each of the two interface terminologies were evaluated by human reviewers, who also searched SNOMED CT to identify better mappings when this was judged to be necessary. Reviewers judged whether they believed the interface terms to be clinically appropriate, whether the terms were covered by SNOMED CT concepts and whether the terms' implied semantic structure could be represented by SNOMED CT. Outcomes included concept coverage by SNOMED CT for study terms and their implied semantics. Agreement statistics and compositionality measures were calculated. The SNOMED CT terminology contained concepts to represent 92.4% of MEDCIN and 95.9% of CHISL terms. Semantic structures implied by study terms were less well covered, with some complex compositional expressions requiring semantics not present in SNOMED CT. Among sampled terms, those from MEDCIN were more complex than those from CHISL, containing an average 3.8 versus 1.8 atomic concepts respectively, pterms.

High resolution extremity CT for biomechanics modeling

International Nuclear Information System (INIS)

Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

1995-01-01

With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling

High resolution extremity CT for biomechanics modeling

Energy Technology Data Exchange (ETDEWEB)

Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

1995-09-23

With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling.

CT and MRT in mediastinal and hilar masses. CT und MRT bei mediastinalen und hilaeren Raumforderungen

Energy Technology Data Exchange (ETDEWEB)

Prayer, L.; Kramer, J.; Stiglbauer, R.; Wimberger, D.; Imhof, H. (Vienna Univ. (Austria). Klinik fuer Radiodiagnostik Ludwig-Boltzmann-Institut fuer Radiologisch-Physikalische Tumordiagnostik, Vienna (Austria)); Metz, V. (Vienna Univ. (Austria). 2. Chirurgische Klinik)

1990-11-01

Thirty-eight patients with mediastinal and/or hilar masses were imaged by computed tomography (CT) and magnetic resonance imaging (MRI). Results were analyzed retrospectively regarding the ability to demonstrate the masses, their number, size, definition, location and tissue characteristics. CT and MRI showed equivalent results in 32 cases; additional information was obtained in two patients by CT, in four patients by MRI. In view of the specific advantages and limitations of both CT and MRI we believed that in patients with mediastinal and/or hilar masses, contrast enhanced CT remains the procedure of choice after performing plain chest radiographs; in certain cases MRI will prove useful for further evaluation. (orig.).

A semantic-based method for extracting concept definitions from scientific publications: evaluation in the autism phenotype domain

OpenAIRE

Hassanpour, Saeed; O?Connor, Martin J; Das, Amar K

2013-01-01

Background A variety of informatics approaches have been developed that use information retrieval, NLP and text-mining techniques to identify biomedical concepts and relations within scientific publications or their sentences. These approaches have not typically addressed the challenge of extracting more complex knowledge such as biomedical definitions. In our efforts to facilitate knowledge acquisition of rule-based definitions of autism phenotypes, we have developed a novel semantic-based t...

Using SNOMED CT to Represent Two Interface Terminologies

Science.gov (United States)

Rosenbloom, S. Trent; Brown, Steven H.; Froehling, David; Bauer, Brent A.; Wahner-Roedler, Dietlind L.; Gregg, William M.; Elkin, Peter L.

2009-01-01

Objective Interface terminologies are designed to support interactions between humans and structured medical information. In particular, many interface terminologies have been developed for structured computer based documentation systems. Experts and policy-makers have recommended that interface terminologies be mapped to reference terminologies. The goal of the current study was to evaluate how well the reference terminology SNOMED CT could map to and represent two interface terminologies, MEDCIN and the Categorical Health Information Structured Lexicon (CHISL). Design Automated mappings between SNOMED CT and 500 terms from each of the two interface terminologies were evaluated by human reviewers, who also searched SNOMED CT to identify better mappings when this was judged to be necessary. Reviewers judged whether they believed the interface terms to be clinically appropriate, whether the terms were covered by SNOMED CT concepts and whether the terms' implied semantic structure could be represented by SNOMED CT. Measurements Outcomes included concept coverage by SNOMED CT for study terms and their implied semantics. Agreement statistics and compositionality measures were calculated. Results The SNOMED CT terminology contained concepts to represent 92.4% of MEDCIN and 95.9% of CHISL terms. Semantic structures implied by study terms were less well covered, with some complex compositional expressions requiring semantics not present in SNOMED CT. Among sampled terms, those from MEDCIN were more complex than those from CHISL, containing an average 3.8 versus 1.8 atomic concepts respectively, pterms. PMID:18952944

Applied behavior analysis as intervention for autism: definition, features and philosophical concepts

Directory of Open Access Journals (Sweden)

Síglia Pimentel Höher Camargo

2013-11-01

Full Text Available Autism spectrum disorder (ASD is a lifelong pervasive developmental disorder with no known causes and cure. However, educational and behavioral interventions with a foundation in applied behavior analysis (ABA have been shown to improve a variety of skill areas such as communication, social, academic, and adaptive behaviors of individuals with ASD. The goal of this work is to present the definition, features and philosophical concepts that underlie ABA and make this science an effective intervention method for people with autism.

ECOLOGICAL LIFESTYLE, THE BASIC PRINCIPLES OF THE OPERATIONAL DEFINITION OF THE CONCEPT

Directory of Open Access Journals (Sweden)

Olesya Nikolaevna Tarasova

2015-12-01

Full Text Available Based on the analysis of approaches to the empirical study of the environmental aspects of lifestyle are presented the basic principles that distinguish ecological way of life off the set of environmental practices that need to be taken into account in empirical measurement, namely: systematicity, conceptuality, contextual conformity and processuality. The article provides a theoretical basis and operational definition as an ecological way of life in general and the principles that distinguish it from other concepts of environmental sociology.

Design concepts of definitive disposal for high level radioactive wastes

International Nuclear Information System (INIS)

Badillo A, V.E.; Alonso V, G.

2007-01-01

It is excessively known the importance about finding a solution for the handling and disposition of radioactive waste of all level. However, the polemic is centered in the administration of high level radioactive waste and the worn out fuel, forgetting that the more important volumes of waste its are generated in the categories of low level wastes or of very low level. Depending on the waste that will be confined and of the costs, several technological modalities of definitive disposition exist, in function of the depth of the confinement. The concept of deep geologic storage, technological option proposed more than 40 years ago, it is a concept of isolation of waste of long half life placed in a deep underground installation dug in geologic formations that are characterized by their high stability and their low flow of underground water. In the last decades, they have registered countless progresses in technical and scientific aspects of the geologic storage, making it a reliable technical solution supported with many years of scientific work carried out by numerous institutions in the entire world. In this work the design concepts that apply some countries for the high level waste disposal that its liberate heat are revised and the different geologic formations that have been considered for the storage of this type of wastes. (Author)

Organic food processing: a framework for concept, starting definitions and evaluation.

Science.gov (United States)

Kahl, Johannes; Alborzi, Farnaz; Beck, Alexander; Bügel, Susanne; Busscher, Nicolaas; Geier, Uwe; Matt, Darja; Meischner, Tabea; Paoletti, Flavio; Pehme, Sirli; Ploeger, Angelika; Rembiałkowska, Ewa; Schmid, Otto; Strassner, Carola; Taupier-Letage, Bruno; Załęcka, Aneta

2014-10-01

In 2007 EU Regulation (EC) 834/2007 introduced principles and criteria for organic food processing. These regulations have been analysed and discussed in several scientific publications and research project reports. Recently, organic food quality was described by principles, aspects and criteria. These principles from organic agriculture were verified and adapted for organic food processing. Different levels for evaluation were suggested. In another document, underlying paradigms and consumer perception of organic food were reviewed against functional food, resulting in identifying integral product identity as the underlying paradigm and a holistic quality view connected to naturalness as consumers' perception of organic food quality. In a European study, the quality concept was applied to the organic food chain, resulting in a problem, namely that clear principles and related criteria were missing to evaluate processing methods. Therefore the goal of this paper is to describe and discuss the topic of organic food processing to make it operational. A conceptual background for organic food processing is given by verifying the underlying paradigms and principles of organic farming and organic food as well as on organic processing. The proposed definition connects organic processing to related systems such as minimal, sustainable and careful, gentle processing, and describes clear principles and related criteria. Based on food examples, such as milk with different heat treatments, the concept and definitions were verified. Organic processing can be defined by clear paradigms and principles and evaluated according criteria from a multidimensional approach. Further work has to be done on developing indicators and parameters for assessment of organic food quality. © 2013 Society of Chemical Industry.

Usefulness of multi-plane dynamic subtraction CT (MPDS-CT) for intracranial high density lesions

Energy Technology Data Exchange (ETDEWEB)

Takagi, Ryo; Kumazaki, Tatsuo [Nippon Medical School, Tokyo (Japan)

1996-02-01

We present a new CT technique using the high speed CT scanner in detection and evaluation of temporal and spatial contrast enhancement of intracranial high density lesions. A multi-plane dynamic subtraction CT (MPDS-CT) was performed in 21 patients with intracranial high density lesions. These lesions consisted of 10 brain tumors, 7 intracerebral hemorrhages and 4 vascular malformations (2 untreated, 2 post-embolization). Baseline study was first performed, and 5 sequential planes of covering total high density lesions were selected. After obtaining the 5 sequential CT images as mask images, three series of multi-plane dynamic CT were performed for the same 5 planes with an intravenous bolus injection of contrast medium. MPDS-CT images were reconstructed by subtracting dynamic CT images from the mask ones. MPDS-CT were compared with conventional contrast-enhanced CT. MPDS-CT images showed the definite contrast enhancement of high density brain tumors and vascular malformations which were not clearly identified on conventional contrast-enhanced CT images because of calcified or hemorrhagic lesions and embolic materials, enabling us to eliminate enhanced abnormalities with non-enhanced areas such as unusual intracerebral hemorrhages. MPDS-CT will provide us further accurate and objective information and will be greatly helpful for interpreting pathophysiologic condition. (author).

CT after transsphenoidal surgery

International Nuclear Information System (INIS)

Tazawa, Satoru

1991-01-01

Two hundred and ten CT studies of 95 patients after transsphenoidal surgery were reviewed. Spheno-ethmoid opacificaiton, intrasellar hematoma and gas bubbles were noted within 2 weeks after surgery. Bone defect of the sellar floor and bone stent were seen on coronal scans in most cases. The packing material frequently disappeared on follow-up studies. Hormonal assessment of the functioning tumor, according to which the effect of treatment was evaluated, was correlated with CT findings. Because differentiation between postoperative changes and residual mass was difficult, there was no definite CT criteria to indicate residual functioning tumor except upward convexity of the diaphragma sellae on CT more than 3 months after surgery. Initial follow up CT study is recommended to be performed at about 3 months after surgery, at which time the immediate postoperative inflammatory changes have been disappeared. The incidence of recurrence was 3/47 (6%), which was shown on follow-up CT from 4 to 10 years after surgery. Therefore, subsequent CT study should be done in every year or two, taking the clinical symptoms and hormonal data into consideration. (author)

CT after transsphenoidal surgery

Energy Technology Data Exchange (ETDEWEB)

Tazawa, Satoru [Tohoku Univ., Sendai (Japan). School of Medicine

1991-03-01

Two hundred and ten CT studies of 95 patients after transsphenoidal surgery were reviewed. Spheno-ethmoid opacificaiton, intrasellar hematoma and gas bubbles were noted within 2 weeks after surgery. Bone defect of the sellar floor and bone stent were seen on coronal scans in most cases. The packing material frequently disappeared on follow-up studies. Hormonal assessment of the functioning tumor, according to which the effect of treatment was evaluated, was correlated with CT findings. Because differentiation between postoperative changes and residual mass was difficult, there was no definite CT criteria to indicate residual functioning tumor except upward convexity of the diaphragma sellae on CT more than 3 months after surgery. Initial follow up CT study is recommended to be performed at about 3 months after surgery, at which time the immediate postoperative inflammatory changes have been disappeared. The incidence of recurrence was 3/47 (6%), which was shown on follow-up CT from 4 to 10 years after surgery. Therefore, subsequent CT study should be done in every year or two, taking the clinical symptoms and hormonal data into consideration. (author).

Concepts and definitions for "supportive care," "best supportive care," "palliative care," and "hospice care" in the published literature, dictionaries, and textbooks.

Science.gov (United States)

Hui, David; De La Cruz, Maxine; Mori, Masanori; Parsons, Henrique A; Kwon, Jung Hye; Torres-Vigil, Isabel; Kim, Sun Hyun; Dev, Rony; Hutchins, Ronald; Liem, Christiana; Kang, Duck-Hee; Bruera, Eduardo

2013-03-01

Commonly used terms such as "supportive care," "best supportive care," "palliative care," and "hospice care" were rarely and inconsistently defined in the palliative oncology literature. We conducted a systematic review of the literature to further identify concepts and definitions for these terms. We searched MEDLINE, PsycInfo, EMBASE, and CINAHL for published peer-reviewed articles from 1948 to 2011 that conceptualized, defined, or examined these terms. Two researchers independently reviewed each citation for inclusion and then extracted the concepts/definitions when available. Dictionaries/textbooks were also searched. Nine of 32 "SC/BSC," 25 of 182 "PC," and 12 of 42 "HC" articles focused on providing a conceptual framework/definition. Common concepts for all three terms were symptom control and quality-of-life for patients with life-limiting illness. "SC" focused more on patients on active treatment compared to other categories (9/9 vs. 8/37) and less often involved interdisciplinary care (4/9 vs. 31/37). In contrast, "HC" focused more on volunteers (6/12 vs. 6/34), bereavement care (9/12 vs. 7/34), and community care (9/12 vs. 6/34). Both "PC" and "SC/BSC" were applicable earlier in the disease trajectory (16/34 vs. 0/9). We found 13, 24, and 17 different definitions for "SC/BSC," "PC," and "HC," respectively. "SC/BSC" was the most variably defined, ranging from symptom management during cancer therapy to survivorship care. Dictionaries/textbooks showed similar findings. We identified defining concepts for "SC/BSC," "PC," and "HC" and developed a preliminary conceptual framework unifying these terms along the continuum of care to help build consensus toward standardized definitions.

FDG-PET/CT in oncology. German guideline

International Nuclear Information System (INIS)

Krause, B.J.; Beyer, T.; Bockisch, A.; Delbeke, D.; Kotzerke, J.; Minkov, V.; Reiser, M.; Willich, N.

2007-01-01

FDG-PET/CT examinations combine metabolic and morphologic imaging within an integrated procedure. Over the past decade PET/CT imaging has gained wide clinical acceptance in the field of oncology. This FDG-PET/CT guideline focuses on indications, data acquisition and processing as well as documentation of FDG-PET/CT examinations in oncologic patients within a clinical and social context specific to Germany. Background information and definitions are followed by examples of clinical and research applications of FDG-PET/CT. Furthermore, protocols for CT scanning (low dose and contrast-enhanced CT) and PET emission imaging are discussed. Documentation and reporting of examinations are specified. Image interpretation criteria and sources of errors are discussed. Quality control for FDG and PET/CT-systems, qualification requirements of personnel as well as legal aspects are presented. (orig.)

Mixed connective tissue disease associated with noted pulmonary CT findings

Energy Technology Data Exchange (ETDEWEB)

Yamazaki, Souji; Tsukada, Atsuko; Furuya, Tatsutaka

1984-10-01

CT was performed in a 56-year-old woman with mixed connective tissue disease (MCTD). Much more definitive pulmonary findings were obtained by CT than by the conventional chest x-ray examination and pulmonary function test. CT findings disclosed pulmonary lesions extremely similar to those in cases of progressive systemic sclerosis. Pulmonary CT was considered useful in examining pulmonary lesions for MCTD.

Thoracic cavity definition for 3D PET/CT analysis and visualization.

Science.gov (United States)

Cheirsilp, Ronnarit; Bascom, Rebecca; Allen, Thomas W; Higgins, William E

2015-07-01

X-ray computed tomography (CT) and positron emission tomography (PET) serve as the standard imaging modalities for lung-cancer management. CT gives anatomical details on diagnostic regions of interest (ROIs), while PET gives highly specific functional information. During the lung-cancer management process, a patient receives a co-registered whole-body PET/CT scan pair and a dedicated high-resolution chest CT scan. With these data, multimodal PET/CT ROI information can be gleaned to facilitate disease management. Effective image segmentation of the thoracic cavity, however, is needed to focus attention on the central chest. We present an automatic method for thoracic cavity segmentation from 3D CT scans. We then demonstrate how the method facilitates 3D ROI localization and visualization in patient multimodal imaging studies. Our segmentation method draws upon digital topological and morphological operations, active-contour analysis, and key organ landmarks. Using a large patient database, the method showed high agreement to ground-truth regions, with a mean coverage=99.2% and leakage=0.52%. Furthermore, it enabled extremely fast computation. For PET/CT lesion analysis, the segmentation method reduced ROI search space by 97.7% for a whole-body scan, or nearly 3 times greater than that achieved by a lung mask. Despite this reduction, we achieved 100% true-positive ROI detection, while also reducing the false-positive (FP) detection rate by >5 times over that achieved with a lung mask. Finally, the method greatly improved PET/CT visualization by eliminating false PET-avid obscurations arising from the heart, bones, and liver. In particular, PET MIP views and fused PET/CT renderings depicted unprecedented clarity of the lesions and neighboring anatomical structures truly relevant to lung-cancer assessment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mixed connective tissue disease associated with noted pulmonary CT findings

International Nuclear Information System (INIS)

Yamazaki, Souji; Tsukada, Atsuko; Furuya, Tatsutaka

1984-01-01

CT was performed in a 56-year-old woman with mixed connective tissue disease (MCTD). Much more definitive pulmonary findings were obtained by CT than by the conventional chest x-ray examination and pulmonary function test. CT findings disclosed pulmonary lesions extremely similar to those in cases of progressive systemic sclerosis. Pulmonary CT was considered useful in examining pulmonary lesions for MCTD. (Namekawa, K.)

Decreased occipital lobe metabolism by FDG-PET/CT

Science.gov (United States)

Solnes, Lilja; Nalluri, Abhinav; Cohen, Jesse; Jones, Krystyna M.; Zan, Elcin; Javadi, Mehrbod S.; Venkatesan, Arun

2017-01-01

Objective: To compare brain metabolism patterns on fluorodeoxyglucose (FDG)-PET/CT in anti–NMDA receptor and other definite autoimmune encephalitis (AE) and to assess how these patterns differ between anti–NMDA receptor neurologic disability groups. Methods: Retrospective review of clinical data and initial dedicated brain FDG-PET/CT studies for neurology inpatients with definite AE, per published consensus criteria, treated at a single academic medical center over a 10-year period. Z-score maps of FDG-PET/CT were made using 3-dimensional stereotactic surface projections in comparison to age group–matched controls. Brain region mean Z scores with magnitudes ≥2.00 were interpreted as significant. Comparisons were made between anti–NMDA receptor and other definite AE patients as well as among patients with anti–NMDA receptor based on modified Rankin Scale (mRS) scores at the time of FDG-PET/CT. Results: The medial occipital lobes were markedly hypometabolic in 6 of 8 patients with anti–NMDA receptor encephalitis and as a group (Z = −4.02, interquartile range [IQR] 2.14) relative to those with definite AE (Z = −2.32, 1.46; p = 0.004). Among patients with anti–NMDA receptor encephalitis, the lateral and medial occipital lobes were markedly hypometabolic for patients with mRS 4–5 (lateral occipital lobe Z = −3.69, IQR 1; medial occipital lobe Z = −4.08, 1) compared with those with mRS 0–3 (lateral occipital lobe Z = −0.83, 2; p occipital lobe Z = −1.07, 2; p = 0.001). Conclusions: Marked medial occipital lobe hypometabolism by dedicated brain FDG-PET/CT may serve as an early biomarker for discriminating anti–NMDA receptor encephalitis from other AE. Resolution of lateral and medial occipital hypometabolism may correlate with improved neurologic status in anti–NMDA receptor encephalitis. PMID:29159205

Incidental internal carotid artery calcifications on temporal bone CT in children

International Nuclear Information System (INIS)

Koch, Bernadette; Jones, Blaise; Blackham, Aaron

2007-01-01

Incidental internal carotid artery (ICA) calcifications are occasionally noted on CT images of the brain and temporal bone. In adults, incidental calcifications have been correlated with increased incidence of hypercholesterolemia, cardiac disease, diabetes and carotid stenosis. To determine the incidence of incidental calcifications of the carotid siphon on temporal bone CT in children. We retrospectively reviewed 24 months of consecutive temporal bone CT examinations in children aged 18 years and younger. CT examinations on 663 patients were reviewed and the presence or absence of ICA calcifications was ranked as absent, questionable or definitive. In patients in whom definitive calcifications were identified, hospital charts were reviewed for evidence of diabetes mellitus, hypercholesterolemia, hypertriglyceridemia, hyperlipidemia and chronic renal disease as potential causes of early atherosclerosis. Of the 663 patients, 25% had definitive calcifications within the wall of the ICA: 6% of children younger than 2 years and 28% of children 12-19 years of age. Incidentally noted ICA calcifications are a common finding on temporal bone CT in children, most likely a physiologic response to turbulent flow at natural bends in the artery rather than secondary to underlying disease predisposing to early atherosclerotic calcification. (orig.)

Incidental internal carotid artery calcifications on temporal bone CT in children

Energy Technology Data Exchange (ETDEWEB)

Koch, Bernadette; Jones, Blaise [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Blackham, Aaron [University of Cincinnati College of Medicine, Cincinnati, OH (United States)

2007-02-15

Incidental internal carotid artery (ICA) calcifications are occasionally noted on CT images of the brain and temporal bone. In adults, incidental calcifications have been correlated with increased incidence of hypercholesterolemia, cardiac disease, diabetes and carotid stenosis. To determine the incidence of incidental calcifications of the carotid siphon on temporal bone CT in children. We retrospectively reviewed 24 months of consecutive temporal bone CT examinations in children aged 18 years and younger. CT examinations on 663 patients were reviewed and the presence or absence of ICA calcifications was ranked as absent, questionable or definitive. In patients in whom definitive calcifications were identified, hospital charts were reviewed for evidence of diabetes mellitus, hypercholesterolemia, hypertriglyceridemia, hyperlipidemia and chronic renal disease as potential causes of early atherosclerosis. Of the 663 patients, 25% had definitive calcifications within the wall of the ICA: 6% of children younger than 2 years and 28% of children 12-19 years of age. Incidentally noted ICA calcifications are a common finding on temporal bone CT in children, most likely a physiologic response to turbulent flow at natural bends in the artery rather than secondary to underlying disease predisposing to early atherosclerotic calcification. (orig.)

Converting from CT- to MRI-only-based target definition in radiotherapy of localized prostate cancer. A comparison between two modalities

Energy Technology Data Exchange (ETDEWEB)

Seppaelae, Tiina; Visapaeae, Harri; Collan, Juhani; Kapanen, Mika; Kouri, Mauri; Tenhunen, Mikko; Saarilahti, Kauko [University of Helsinki and Helsinki University Hospital, Comprehensive Cancer Center, POB 180, Helsinki (Finland); Beule, Annette [University of Helsinki and Helsinki University Hospital, HUS Medical Imaging Center, Radiology, POB 180, Helsinki (Finland)

2015-11-15

To investigate the conversion of prostate cancer radiotherapy (RT) target definition from CT-based planning into an MRI-only-based planning procedure. Using the CT- and MRI-only-based RT planning protocols, 30 prostate cancer patients were imaged in the RT fixation position. Two physicians delineated the prostate in both CT and T2-weighted MRI images. The CT and MRI images were coregistered based on gold seeds and anatomic borders of the prostate. The uncertainty of the coregistration, as well as differences in target volumes and uncertainty of contour delineation were investigated. Conversion of margins and dose constraints from CT- to MRI-only-based treatment planning was assessed. On average, the uncertainty of image coregistration was 0.4 ± 0.5 mm (one standard deviation, SD), 0.9 ± 0.8 mm and 0.9 ± 0.9 mm in the lateral, anterior-posterior and base-apex direction, respectively. The average ratio of the prostate volume between CT and MRI was 1.20 ± 0.15 (one SD). Compared to the CT-based contours, the MRI-based contours were on average 2-7 mm smaller in the apex, 0-1 mm smaller in the rectal direction and 1-4 mm smaller elsewhere. When converting from a CT-based planning procedure to an MRI-based one, the overall planning target volumes (PTV) are prominently reduced only in the apex. The prostate margins and dose constraints can be retained by this conversion. (orig.) [German] Ziel unserer Studie war es, die Umstellung der Strahlentherapieplanung des Prostatakarzinoms von CT-gestuetzter in ausschliesslich MR-gestuetzte Zieldefinition zu untersuchen. Bei 30 Patienten mit Prostatakarzinom wurden eine CT und eine MRT unter Planungsbedingungen durchgefuehrt. Zwei Untersucher konturierten die Prostata in CT- und T2-gewichteten MR-Bildern. Mit Hilfe der Position von Goldstiften und der anatomischen Grenzen der Prostata wurden die CT- und MR-Bilder koregistriert. Es wurden die Genauigkeit der Koregistrierung sowie die Unterschiede der Zielvolumina und der

Fire regime: history and definition of a key concept in disturbance ecology.

Science.gov (United States)

Krebs, Patrik; Pezzatti, Gianni B; Mazzoleni, Stefano; Talbot, Lee M; Conedera, Marco

2010-06-01

"Fire regime" has become, in recent decades, a key concept in many scientific domains. In spite of its wide spread use, the concept still lacks a clear and wide established definition. Many believe that it was first discussed in a famous report on national park management in the United States, and that it may be simply defined as a selection of a few measurable parameters that summarize the fire occurrence patterns in an area. This view has been uncritically perpetuated in the scientific community in the last decades. In this paper we attempt a historical reconstruction of the origin, the evolution and the current meaning of "fire regime" as a concept. Its roots go back to the 19th century in France and to the first half of the 20th century in French African colonies. The "fire regime" concept took time to evolve and pass from French into English usage and thus to the whole scientific community. This coincided with a paradigm shift in the early 1960s in the United States, where a favourable cultural, social and scientific climate led to the natural role of fires as a major disturbance in ecosystem dynamics becoming fully acknowledged. Today the concept of "fire regime" refers to a collection of several fire-related parameters that may be organized, assembled and used in different ways according to the needs of the users. A structure for the most relevant categories of parameters is proposed, aiming to contribute to a unified concept of "fire regime" that can reconcile the physical nature of fire with the socio-ecological context within which it occurs.

Clinical study of retrocaval ureter diagnosed by CT scan

International Nuclear Information System (INIS)

Kiriyama, Isao; Hata, Ryosuke; Amemiya, Hiroshi

1987-01-01

Although retrocaval ureter is relatively uncommon congenital anomaly, surgical intervention is often necessary to alleviate the clinical signs and symptoms of the patients. Vena cavography has been indispensable imaging modality for the definitive diagnosis of this anomaly. Recently, however, CT scan in addition to excretory urography (IVP) and retrograde pyelography(RP) has been utilized in many reported cases in the diagnosis of retrocaval ureter. We have experienced 3 cases of retrocaval ureter consecutively. In this paper we report these 3 cases of retrocaval ureter, in which CT scan enabled us to confirm the definitive diagnosis. We also report another case of pelviureteric stenosis that was taken for retrocaval ureter by CT scan. Causes of the misdiagnosis is discussed. In conclusion CT scan is useful diagnostic modality in the diagnosis of retrocaval ureter and this lesser invasive technique might lessen the need for vena cavography. (author)

COBE: A Conjunctive Ontology Browser and Explorer for Visualizing SNOMED CT Fragments.

Science.gov (United States)

Sun, Mengmeng; Zhu, Wei; Tao, Shiqiang; Cui, Licong; Zhang, Guo-Qiang

2015-01-01

Ontology search interfaces can benefit from the latest information retrieval advances. This paper introduces a Conjunctive Ontology Browser and Explorer (COBE) for searching and exploring SNOMED CT concepts and visualizing SNOMED CT fragments. COBE combines navigational exploration (NE) with direct lookup (DL) as two complementary modes for finding specific SNOMED CT concepts. The NE mode allows a user to interactively and incrementally narrow down (hence conjunctive) the search space by adding word stems, one at a time. Such word stems serve as attribute constraints, or "attributes" in Formal Concept Analysis, which allows the user to navigate to specific SNOMED CT concept clusters. The DL mode represents the common search mechanism by using a collection of key words, as well as concept identifiers. With respect to the DL mode, evaluation against manually created reference standard showed that COBE attains an example-based precision of 0.958, recall of 0.917, and F1 measure of 0.875. With respect to the NE mode, COBE leverages 28,371 concepts in non-lattice fragments to construct the stem cloud. With merely 9.37% of the total SNOMED CT stem cloud, our navigational exploration mode covers 98.97% of the entire concept collection.

Iterative Reconstruction Techniques in Abdominopelvic CT: Technical Concepts and Clinical Implementation.

Science.gov (United States)

Patino, Manuel; Fuentes, Jorge M; Singh, Sarabjeet; Hahn, Peter F; Sahani, Dushyant V

2015-07-01

This article discusses the clinical challenge of low-radiation-dose examinations, the commonly used approaches for dose optimization, and their effect on image quality. We emphasize practical aspects of the different iterative reconstruction techniques, along with their benefits, pitfalls, and clinical implementation. The widespread use of CT has raised concerns about potential radiation risks, motivating diverse strategies to reduce the radiation dose associated with CT. CT manufacturers have developed alternative reconstruction algorithms intended to improve image quality on dose-optimized CT studies, mainly through noise and artifact reduction. Iterative reconstruction techniques take unique approaches to noise reduction and provide distinct strength levels or settings.

CT findings of medulloblastoma

International Nuclear Information System (INIS)

Tsuchida, Tadashi; Fukuda, Mitsunori; Takeda, Norio; Tanaka, Ryuichi; Ito, Jusuke.

1982-01-01

Computed tomography (CT) of ten patients with medulloblastomas was evaluated. Six of them showed solid, nearly homogeneous lesions and a definite enhancement after the infusion of the contrast medium. However, 4 cases showed heterogenous mass lesions composed of areas of a low density and an iso- or slightly high density which was attenuated by contrast enhancement. Histological examinations revealed differentiated medulloblastomas in two of them, but the other two cases were typical medulloblastomas. It should be remembered that medulloblastomas can reveal heterogenous cerebellar midline mass lesions in CT scans. (author)

Clinical value of SPECT/CT imaging in the diagnosis of bone metastasis

International Nuclear Information System (INIS)

Wang Xinhua; Zhao Yanping; Lu Haijian; Dong Zhanfei

2010-01-01

Objective: To evaluate the clinical value of 99 Tc m -methylene diphosphonic acid (MDP) SPECT/CT imaging for the diagnosis of bone metastasis. Methods: Patients suspected for bone metastasis and with bone pain of unknown origin were included in this study (n=237). All cases underwent SPECT and CT imaging at 180 min after 99 Tc m -MDP injection. Diagnosis was confirmed by pathology (n=21), more than 2 kinds of radiologieal imaging (MRI, CT, X-ray) (n=106), and clinical follow up in 2 years (n=110). χ 2 -test was used to compare the results of planar and SPECT/CT imaging using SAS 6.12 software. Results: In 237 patients, planar imaging of 142 cases matched the final diagnosis in which 72 had benign lesions and 70 had bone metastases. The definite coincidence rate was 95.30% (142/149). SPECT/CT imaging of 224 cases matched the final diagnosis in which 104 had benign lesions and 120 cases diagnosed as bone metastases. The coincidence and definite coincidence rates were 94.51% (224/237), and 99.48% (192/193). Difference in the definite coincidence rate between planar and SPECT/CT imaging was statistically significant (χ 2 = 5.37, P=0.024). Conclusion: SPECT/CT imaging is valuable for accurate localization of osseous pathology and for improvement of diagnosing bone metastasis. (authors)

Self-Concept Is a Concept Worth Considering

Science.gov (United States)

Shields, Nora

2009-01-01

There is a growing recognition of the importance of self-concept in the pediatric rehabilitation research literature. There also is confusion and inconsistency in the definitions of and the terminology used to describe self-concept. What is agreed is that self-concept is multidimensional, comprising a child's perception of their personal…

Three-dimensional reconstruction of CT images

Energy Technology Data Exchange (ETDEWEB)

Watanabe, Toshiaki; Kattoh, Keiichi; Kawakami, Genichiroh; Igami, Isao; Mariya, Yasushi; Nakamura, Yasuhiko; Saitoh, Yohko; Tamura, Koreroku; Shinozaki, Tatsuyo

1986-09-01

Computed tomography (CT) has the ability to provide sensitive visualization of organs and lesions. Owing to the nature of CT to be transaxial images, a structure which is greater than a certain size appears as several serial CT images. Consequently each observer must reconstruct those images into a three-dimensional (3-D) form mentally. It has been supposed to be of great use if such a 3-D form can be described as a definite figure. A new computer program has been developed which can produce 3-D figures from the profiles of organs and lesions on CT images using spline curves. The figures obtained through this method are regarded to have practical applications.

Radiotherapy and the importance of CT for the nasopharyngeal squammous cell carcinoma, 1

International Nuclear Information System (INIS)

Yamashita, Shoji; Dokiya, Takushi.

1987-01-01

Thirty-five patients with nasopharyngeal squamous cell carcinoma (NPC) were examined with computed tomography (CT) before definitive radiotherapy. CT clearly delincated the extent of the primary tumors. CT frequently showed subtle destruction of the paranasal sinuses and pterygoid plate, which was not usually detected by conventional X-ray examinations. T-staging was made according to the UICC TNM classification system (1978), depending on the clinical findings and the conventional X-ray examinations (non-CT T-stage). Then the non-CT T-stage of each patient was compared with T-stage diagnosed with CT findings alone (CT T-stage). CT upstaged non-CT T-stage in 14 of the 35 patients. Only one patient was downstaged by CT ; this patient had cranial nerve palsy but no detectable bone destruction as shown by CT. Since CT can reveal both bones and abnormal soft tissues well, it is a very useful diagnostic tool for the staging of the tumor assessment of treatment planning. Before radiotherapy, we should use CT to confirm that whether the tumor was located within the radiation field. CT is also useful to see the tumor regression after definitive radiotherapy. We conclude that CT is the single, most reliable imaging method for primary tumors of the NPC patients. (author)

Head trauma and CT

International Nuclear Information System (INIS)

Samejima, Kanji; Yoshii, Nobuo; Tobari, Chitoshi

1979-01-01

It has been said that chronic subdural hematoma cannot be diagnosed by CT. In our cases, CT was used, and the results were described. According to the density of the picture, CT findings of chronic subdural hematoma could be classified into 3 types, those of higher density than that of the cerebral paranchyma, those of isodensity, and those of lower density than that of the cerebral parenchyma. The difference among them appeared to be due to variation in the fluid in hematoma, especially that in hemoglobin concentration. Chronic subdural hematoma was found in 27 of 388 cases of head trauma in which CT was undertaken in our department of surgery for last 2 years. It is difficult to differenciate this disease from subdural edema or subarachnoideal retention of the cerebrospinal fluid. In many cases, use of contrast medium added no change to the CT picture. Cerebral angiography is necessary for definite diagnosis of the disease. Chronic subdural hematoma gives more varieties of findings than other intracranial hematomas. However, if the film is very carefully read, CT is still useful for diagnosing this disease in spite of initially remarked difficulties. (Ueda, J.)

Non-enhanced CT versus contrast-enhanced CT in integrated PET/CT studies for nodal staging of rectal cancer

International Nuclear Information System (INIS)

Tateishi, Ukihide; Maeda, Tetsuo; Morimoto, Tsuyoshi; Miyake, Mototaka; Arai, Yasuaki; Kim, E.E.

2007-01-01

The purpose of the present study was to determine the diagnostic accuracy of non-enhanced CT and contrast-enhanced CT in integrated PET/CT studies for preoperative nodal staging of rectal cancer. Retrospective analysis was performed in 53 patients with pathologically proven rectal cancer who had been referred for preoperative staging. All patients underwent integrated PET/CT consisting of non-enhanced and contrast-enhanced CT followed by whole-body fluorine-18-fluorodeoxyglucose ([ 18 F]FDG) PET. Both non-enhanced and contrast-enhanced PET/CT images were evaluated separately by two observers in consensus. The reference standard was histopathologic results. For nodal staging of rectal cancer, we compared diagnostic accuracy on a per-patient basis between the two modalities. Nodal staging was correctly determined with non-enhanced studies in 37 patients (70%) and with contrast-enhanced studies in 42 patients (79%). On a per-patient basis, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of regional lymph node staging were 85%, 68%, 83%, 72%, and 79%, respectively, with contrast-enhanced studies, and 85%, 42%, 73%, 62%, and 70%, respectively, with non-enhanced studies. The difference in the accuracy of nodal staging between the two modalities was not significant (p = 0.063). Compared with non-enhanced studies, contrast-enhanced studies determined more correctly the status of pararectal lymph nodes (p 0.002), internal iliac lymph nodes (p = 0.004), and obturator lymph nodes (p < 0.0001). Contrast-enhanced PET/CT is superior to non-enhanced PET/CT for precise definition of regional nodal status in rectal cancer. (orig.)

The influence of respiratory motion on CT image volume definition

Energy Technology Data Exchange (ETDEWEB)

Rodríguez-Romero, Ruth, E-mail: rrromero@salud.madrid.org; Castro-Tejero, Pablo, E-mail: pablo.castro@salud.madrid.org [Servicio de Radiofísica y Protección Radiológica, Hospital Universitario Puerta de Hierro Majadahonda, 28222 Madrid (Spain)

2014-04-15

Purpose: Radiotherapy treatments are based on geometric and density information acquired from patient CT scans. It is well established that breathing motion during scan acquisition induces motion artifacts in CT images, which can alter the size, shape, and density of a patient's anatomy. The aim of this work is to examine and evaluate the impact of breathing motion on multislice CT imaging with respiratory synchronization (4DCT) and without it (3DCT). Methods: A specific phantom with a movable insert was used. Static and dynamic phantom acquisitions were obtained with a multislice CT. Four sinusoidal breath patterns were simulated to move known geometric structures longitudinally. Respiratory synchronized acquisitions (4DCT) were performed to generate images during inhale, intermediate, and exhale phases using prospective and retrospective techniques. Static phantom data were acquired in helical and sequential mode to define a baseline for each type of respiratory 4DCT technique. Taking into account the fact that respiratory 4DCT is not always available, 3DCT helical image studies were also acquired for several CT rotation periods. To study breath and acquisition coupling when respiratory 4DCT was not performed, the beginning of the CT image acquisition was matched with inhale, intermediate, or exhale respiratory phases, for each breath pattern. Other coupling scenarios were evaluated by simulating different phantom and CT acquisition parameters. Motion induced variations in shape and density were quantified by automatic threshold volume generation and Dice similarity coefficient calculation. The structure mass center positions were also determined to make a comparison with their theoretical expected position. Results: 4DCT acquisitions provided volume and position accuracies within ±3% and ±2 mm for structure dimensions >2 cm, breath amplitude ≤15 mm, and breath period ≥3 s. The smallest object (1 cm diameter) exceeded 5% volume variation for the breath

CT of sella after pituitary surgery

International Nuclear Information System (INIS)

Frank, W.; Imhof, H.; Schratter, M.; Knosp, E.

1986-01-01

A CT control scan of 32 patients after transsphenoidal resection of a pituitary tumour revealed sellar contents of different density and varying extent. Additional criteria were used to differentiate the intrasellar structures (size, extent, shape, structure, contrast enhancement, bone changes). CT made the definite diagnosis in 6 patients with pituitary tumour recurrence. Hormonal measurements were superior to CT in identifying recurrent tumours in another 3 patients. It is concluded that hormonal methods should be used in evaluating patients after surgery of a hormone-producing tumour. However, CT is the most useful method in detecting tumour recurrence in patients with non-functioning adenomas, and, if an adequate technique is used (coronal scanning, iv-contrast), even clinical asymptomatic tumours can be identified. (orig.) [de

Temporal resolution and motion artifacts in single-source and dual-source cardiac CT.

Science.gov (United States)

Schöndube, Harald; Allmendinger, Thomas; Stierstorfer, Karl; Bruder, Herbert; Flohr, Thomas

2013-03-01

The temporal resolution of a given image in cardiac computed tomography (CT) has so far mostly been determined from the amount of CT data employed for the reconstruction of that image. The purpose of this paper is to examine the applicability of such measures to the newly introduced modality of dual-source CT as well as to methods aiming to provide improved temporal resolution by means of an advanced image reconstruction algorithm. To provide a solid base for the examinations described in this paper, an extensive review of temporal resolution in conventional single-source CT is given first. Two different measures for assessing temporal resolution with respect to the amount of data involved are introduced, namely, either taking the full width at half maximum of the respective data weighting function (FWHM-TR) or the total width of the weighting function (total TR) as a base of the assessment. Image reconstruction using both a direct fan-beam filtered backprojection with Parker weighting as well as using a parallel-beam rebinning step are considered. The theory of assessing temporal resolution by means of the data involved is then extended to dual-source CT. Finally, three different advanced iterative reconstruction methods that all use the same input data are compared with respect to the resulting motion artifact level. For brevity and simplicity, the examinations are limited to two-dimensional data acquisition and reconstruction. However, all results and conclusions presented in this paper are also directly applicable to both circular and helical cone-beam CT. While the concept of total TR can directly be applied to dual-source CT, the definition of the FWHM of a weighting function needs to be slightly extended to be applicable to this modality. The three different advanced iterative reconstruction methods examined in this paper result in significantly different images with respect to their motion artifact level, despite exactly the same amount of data being used

Temporal resolution and motion artifacts in single-source and dual-source cardiac CT

International Nuclear Information System (INIS)

Schöndube, Harald; Allmendinger, Thomas; Stierstorfer, Karl; Bruder, Herbert; Flohr, Thomas

2013-01-01

Purpose: The temporal resolution of a given image in cardiac computed tomography (CT) has so far mostly been determined from the amount of CT data employed for the reconstruction of that image. The purpose of this paper is to examine the applicability of such measures to the newly introduced modality of dual-source CT as well as to methods aiming to provide improved temporal resolution by means of an advanced image reconstruction algorithm. Methods: To provide a solid base for the examinations described in this paper, an extensive review of temporal resolution in conventional single-source CT is given first. Two different measures for assessing temporal resolution with respect to the amount of data involved are introduced, namely, either taking the full width at half maximum of the respective data weighting function (FWHM-TR) or the total width of the weighting function (total TR) as a base of the assessment. Image reconstruction using both a direct fan-beam filtered backprojection with Parker weighting as well as using a parallel-beam rebinning step are considered. The theory of assessing temporal resolution by means of the data involved is then extended to dual-source CT. Finally, three different advanced iterative reconstruction methods that all use the same input data are compared with respect to the resulting motion artifact level. For brevity and simplicity, the examinations are limited to two-dimensional data acquisition and reconstruction. However, all results and conclusions presented in this paper are also directly applicable to both circular and helical cone-beam CT. Results: While the concept of total TR can directly be applied to dual-source CT, the definition of the FWHM of a weighting function needs to be slightly extended to be applicable to this modality. The three different advanced iterative reconstruction methods examined in this paper result in significantly different images with respect to their motion artifact level, despite exactly the same

The concept and definition of therapeutic inertia in hypertension in primary care: a qualitative systematic review.

Science.gov (United States)

Lebeau, Jean-Pierre; Cadwallader, Jean-Sébastien; Aubin-Auger, Isabelle; Mercier, Alain; Pasquet, Thomas; Rusch, Emmanuel; Hendrickx, Kristin; Vermeire, Etienne

2014-07-02

Therapeutic inertia has been defined as the failure of health-care provider to initiate or intensify therapy when therapeutic goals are not reached. It is regarded as a major cause of uncontrolled hypertension. The exploration of its causes and the interventions to reduce it are plagued by unclear conceptualizations and hypothesized mechanisms. We therefore systematically searched the literature for definitions and discussions on the concept of therapeutic inertia in hypertension in primary care, to try and form an operational definition. A systematic review of all types of publications related to clinical inertia in hypertension was performed. Medline, EMbase, PsycInfo, the Cochrane library and databases, BDSP, CRD and NGC were searched from the start of their databases to June 2013. Articles were selected independently by two authors on the basis of their conceptual content, without other eligibility criteria or formal quality appraisal. Qualitative data were extracted independently by two teams of authors. Data were analyzed using a constant comparative qualitative method. The final selection included 89 articles. 112 codes were grouped in 4 categories: terms and definitions (semantics), "who" (physician, patient or system), "how and why" (mechanisms and reasons), and "appropriateness". Regarding each of these categories, a number of contradictory assertions were found, most of them relying on little or no empirical data. Overall, the limits of what should be considered as inertia were not clear. A number of authors insisted that what was considered deleterious inertia might in fact be appropriate care, depending on the situation. Our data analysis revealed a major lack of conceptualization of therapeutic inertia in hypertension and important discrepancies regarding its possible causes, mechanisms and outcomes. The concept should be split in two parts: appropriate inaction and inappropriate inertia. The development of consensual and operational definitions

Vocal cord paralysis due to extralaryngeal causes : evaluation with CT

International Nuclear Information System (INIS)

Lee, Jong Hwa; Mo, Jong Hyun; Moon, Sung Hee; Na, Dong Gyu; Byun, Hong Sik; Cho, Jae Min; Han, Boo Kyung; Son, Young Ik; Baek, Chung Whan

1999-01-01

To evaluate the use of CT in patients with vocal cord paralysis due to extralaryngeal causes, and to use CT for the assessment of extralaryngeal diseases causing vocal cord paralysis. We prospectively studied the results of CT in 41 patients with vocal cord paralysis in whom laryngoscopy revealed no laryngeal cause and physical examination demonstrated no definite extralaryngeal cause. The extralaryngeal cause of vocal cord palsy was determined after comprehensive clinical diagnosis. Enhanced CT scans were acquired from the skull base and continued to the level of the aorticopulmonary window. We used CT to assess the detection rate for extralaryngeal causes and to extimate the extent of extralaryngeal disease and the distribution of lesions. CT revealed that in 20 of 41 patients(49%) the extralarygeal causes of vocal paralysis were as follows : thyroid cancer(n=10), nodal disease(n=6), esophageal cancer(n=2), neurogenic tumor(n=1), aortic aneurysm(n=1). Lesions were located on the left side in 13 patients(65%), and in the tracheoesophageal groove in 15(75%). In patients with vocal cord paralysis in whom no definite lesion is seen on physical examination , CT could be a useful primary imaging method for the assessment of extralaryngeal causes

Evaluation of CT findings for diagnosis of pleural effusions

International Nuclear Information System (INIS)

Arenas-Jimenez, J.; Alonso-Charterina, S.; Fernandez-Latorre, F.; Gil-Sanchez, S.; Sanchez-Paya, J.; Lloret-Llorens, M.

2000-01-01

Computed tomography studies are usually used to assess patients with pleural effusions, and radiologists should be aware of the significance of different CT findings for the diagnosis of the effusion. The purpose of this study was to evaluate CT findings for etiological diagnosis of pleural effusions. Contrast-enhanced CT of the chest of 211 patients with pleural effusion of definite diagnosis were evaluated. The CT images were evaluated for the presence and extent of pleural effusion, thickening or nodules, extrapleural fat and other changes in the mediastinum or lung. The CT scans were read by two independent observers and correlation between them was evaluated. Comparison of CT findings between benign and malignant effusions, between exudates and transudates, and between empyemas and the other parapneumonic effusions were carried out. Kappa values for most CT findings were >0.85. Loculation, pleural thickening, pleural nodules, and extrapleural fat of increased density were only present in exudative effusions. Multiple pleural nodules and nodular pleural thickening were the only pleural findings limited to malignant pleural effusions. The signs were also more frequently seen in empyemas than in other parapneumonic effusions. Computed tomography findings can help to distinguish between transudates and exudates. Although there is some overlap between benign and malignant pleural effusions, pleural nodules and nodular pleural thickening were present almost exclusively in the latter. Although differences between CT findings of empyemas and the other parapneumonic effusions exist, there is no finding which can definitely differentiate between them. (orig.)

Radiation exposure during CT-guided biopsies: recent CT machines provide markedly lower doses.

Science.gov (United States)

Guberina, Nika; Forsting, Michael; Ringelstein, Adrian; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Theysohn, Jens; Wetter, Axel

2018-03-28

To examine radiation dose levels of CT-guided interventional procedures of chest, abdomen, spine and extremities on different CT-scanner generations at a large multicentre institute. 1,219 CT-guided interventional biopsies of different organ regions ((A) abdomen (n=516), (B) chest (n=528), (C) spine (n=134) and (D) extremities (n=41)) on different CT-scanners ((I) SOMATOM-Definition-AS+, (II) Volume-Zoom, (III) Emotion6) were included from 2013-2016. Important CT-parameters and standard dose-descriptors were retrospectively examined. Additionally, effective dose and organ doses were calculated using Monte-Carlo simulation, following ICRP103. Overall, radiation doses for CT interventions are highly dependent on CT-scanner generation: the newer the CT scanner, the lower the radiation dose imparted to patients. Mean effective doses for each of four procedures on available scanners are: (A) (I) 9.3mSv versus (II) 13.9mSv (B) (I) 7.3mSv versus (III) 11.4mSv (C) (I) 6.3mSv versus (II) 7.4mSv (D) (I) 4.3mSv versus (II) 10.8mSv. Standard dose descriptors [standard deviation (SD); CT dose index vol (CTDI vol ); dose-length product (DLP body ); size-specific dose estimate (SSDE)] were also compared. Effective dose, organ doses and SSDE for various CT-guided interventional biopsies on different CT-scanner generations following recommendations of the ICRP103 are provided. New CT-scanner generations involve markedly lower radiation doses versus older devices. • Effective dose, organ dose and SSDE are provided for CT-guided interventional examinations. • These data allow identifying organs at risk of higher radiation dose. • Detailed knowledge of radiation dose may contribute to a better individual risk-stratification. • New CT-scanner generations involve markedly lower radiation doses compared to older devices.

Reconstruction of MRI/CT compatible ring and tandem applicators in CT or MRI images used for treatment planning in brachytherapy

International Nuclear Information System (INIS)

Surendran, N.; Kim, Hayeon; Beriwal, Sushil; Saiful Huq, M.

2008-01-01

Brachytherapy (BT) plays a crucial role in the management of invasive cervix cancer from stage I to IV. Intracavitary techniques are based on afterloading devices, with different types of applicators. CT and/or MRI compatible applicators allow a sectional image based approach with a better assessment of gross tumour volume (GTV) and definition and delineation of target volume (CTV) compared to traditional approaches. To evaluate reconstruction of MRI/CT compatible ring and tandem applicators in 3D CT or MRI images used for treatment planning in Brachytherapy

PERFORMANCE - AN EVOLVING CONCEPT

OpenAIRE

Assist. Mirela-Oana Pintea Ph.D Student; Lect. Monica-Violeta Achim

2010-01-01

The concept of performance is a problematic concept and will remain so as long as the definition of company performance varies depending on the interests of users of information. On this consideration, no consensus was reached regarding the definition, methodology and performance models used. Defining this concept is realized in accordance with its objectives of users of information, while the methodology and models used are influenced by legal regulations and management policies. The approac...

Distribution of lymph node metastases on FDG-PET/CT in inoperable or unresectable oesophageal cancer patients and the impact on target volume definition in radiation therapy

International Nuclear Information System (INIS)

Machiels, Melanie; Geijsen, Elisabeth D.; Van Os, Rob M.; Hulshof, Maarten CCM; Wouterse, Sanne J.; Bennink, Roel J.; Van Laarhoven, Hanneke WM.

2016-01-01

Definitive chemoradiotherapy (dCRT) is standard care for localised inoperable/unresectable oesophageal tumours. Many surgical series have reported on distribution of lymph node metastases (LNM) in resected patients. However, no data is available on the distribution of at-risk LN regions in this more unfavourable patient group. This study aimed to determine the spread of LNM using FDG-PET/CT, to compare it with the distribution in surgical series and to define its impact on the definition of elective LN irradiation (ENI). FDG-PET/CT images of patients with oesophageal cancer treated with dCRT (from 2003 to 2013) were reviewed to identify the anatomic distribution of FDG-avid LNs. Tumours were divided according to proximal, mid-thoracic or distal localisation. About 105 consecutive patients entered analysis. The highest numbers of FDG-avid LNs in proximal tumours were at LN station 101R (45%) and 106recL (35%). For mid-thoracic tumours at 104R (30%) and 105 (30%). For tumours located in the distal oesophagus, the most common sites were along the lesser curvature of the stomach (21%) and the left gastric artery (21%). Except for the supraclavicular and pretracheal nodes, there were no positive locoregional LNM found outside the standard surgical resection area. Our results show a good correlation between the distribution of nodal volumes at risk in surgical series and on FDG-PET/CT. The results can be used to determine target definition in dCRT for oesophageal cancer. For mid-thoracic tumours, the current target delineation guidelines may be extended based on the risk of node involvement, but more clinical studies are needed to determine if the potential harm of expanding the CTV outweighs the potential benefit.

Distribution of lymph node metastases on FDG-PET/CT in inoperable or unresectable oesophageal cancer patients and the impact on target volume definition in radiation therapy.

Science.gov (United States)

Machiels, Melanie; Wouterse, Sanne J; Geijsen, Elisabeth D; van Os, Rob M; Bennink, Roel J; van Laarhoven, Hanneke Wm; Hulshof, Maarten Ccm

2016-08-01

Definitive chemoradiotherapy (dCRT) is standard care for localised inoperable/unresectable oesophageal tumours. Many surgical series have reported on distribution of lymph node metastases (LNM) in resected patients. However, no data is available on the distribution of at-risk LN regions in this more unfavourable patient group. This study aimed to determine the spread of LNM using FDG-PET/CT, to compare it with the distribution in surgical series and to define its impact on the definition of elective LN irradiation (ENI). FDG-PET/CT images of patients with oesophageal cancer treated with dCRT (from 2003 to 2013) were reviewed to identify the anatomic distribution of FDG-avid LNs. Tumours were divided according to proximal, mid-thoracic or distal localisation. About 105 consecutive patients entered analysis. The highest numbers of FDG-avid LNs in proximal tumours were at LN station 101R (45%) and 106recL (35%). For mid-thoracic tumours at 104R (30%) and 105 (30%). For tumours located in the distal oesophagus, the most common sites were along the lesser curvature of the stomach (21%) and the left gastric artery (21%). Except for the supraclavicular and pretracheal nodes, there were no positive locoregional LNM found outside the standard surgical resection area. Our results show a good correlation between the distribution of nodal volumes at risk in surgical series and on FDG-PET/CT. The results can be used to determine target definition in dCRT for oesophageal cancer. For mid-thoracic tumours, the current target delineation guidelines may be extended based on the risk of node involvement, but more clinical studies are needed to determine if the potential harm of expanding the CTV outweighs the potential benefit. © 2016 The Royal Australian and New Zealand College of Radiologists.

Stress: a concept analysis.

Science.gov (United States)

Goodnite, Patricia M

2014-01-01

To analyze the concept of stress and provide an operational definition of stress. Literature review revealed that stress is a commonly used, but often ambiguous, term. Findings supported a definition of stress entailing an individual's perception of a stimulus as overwhelming, which in turn elicits a measurable response resulting in a transformed state. This analysis adopts a dynamic definition of stress that may serve to encourage communication, promote reflection, and enhance concept understanding. This definition may provide direction for future work, as well as enhance efforts to serve patients affected by stress. © 2013 Wiley Periodicals, Inc.

CT scan of Parkinson's disease

Energy Technology Data Exchange (ETDEWEB)

Konishi, T; Noguchi, S; Nishitani, H [National Sanatorium of Utano, Kyoto (Japan); Kitano, H; Ikegami, Y

1981-04-01

In forty-eight patients with Parkinson's disease, we examined the ventricular size and the degree of cortical atrophy which were measured by the photos of CT scan and compared them with their clinical symptoms and side effects of anti-parkinsonian drugs. The ventricular size was expressed as the ventricular ratio which is the percentage of superimposed lateral ventricular area to the white and gray matter area at the slice number 2B of CT scan photos. The degree of the cortical atrophy was expressed as the sulcal numbers which were clearly visualized at the slice number 3B or 4A of CT scan photos. We used the CT scan photos of age-matched other patients which did not show definit central nervous system abnormalities. Our findings were as follows: (1) The ventricular enlargement was observed in the parkinsonian patients who showed dementia and/or Yahr's classification grades IV or V. (2) There was no correlation between the duration of this disease and the L--dopa treatments with the ventricular size and sulcal numbers. (3) The side effects of drugs such as visual hallucination were tended to be observed in the patients who showed the ventricular enlargement. (4) There was no definite correlation between the degree of cortical atrophy with clinical symptoms and side effects of various drugs. These findings suggested that the ventricular enlargement in Parkinson's disease was an important sign of dementia and the tendency of appearance of side effects of various drugs.

CT scan of Parkinson's disease

International Nuclear Information System (INIS)

Konishi, Tetsuro; Noguchi, Sadako; Nishitani, Hiroshi; Kitano, Haruo; Ikegami, Yoshinori.

1981-01-01

In forty-eight patients with Parkinson's disease, we examined the ventricular size and the degree of cortical atrophy which were measured by the photos of CT scan and compared them with their clinical symptoms and side effects of anti-parkinsonian drugs. The ventricular size was expressed as the ventricular ratio which is the percentage of superimposed lateral ventricular area to the white and gray matter area at the slice number 2B of CT scan photos. The degree of the cortical atrophy was expressed as the sulcal numbers which were clearly visualized at the slice number 3B or 4A of CT scan photos. We used the CT scan photos of age-matched other patients which did not show definit central nervous system abnormalities. Our findings were as follows: (1) The ventricular enlargement was observed in the parkinsonian patients who showed dementia and/or Yahr's classification grades IV or V. (2) There was no correlation between the duration of this disease and the L--dopa treatments with the ventricular size and sulcal numbers. (3) The side effects of drugs such as visual hallucination were tended to be observed in the patients who showed the ventricular enlargement. (4) There was no definite correlation between the degree of cortical atrophy with clinical symptoms and side effects of various drugs. These findings suggested that the ventricular enlargement in Parkinson's disease was an important sign of dementia and the tendency of appearance of side effects of various drugs. (author)

[Acute schizophrenia concept and definition: investigation of a French psychiatrist population].

Science.gov (United States)

Baylé, F J; Misdrahi, D; Llorca, P M; Lançon, C; Olivier, V; Quintin, P; Azorin, J M

2005-01-01

For schizophrenic disorders, the clinical conception of "acute state" is widely used in clinical settings to assess the effectiveness of therapeutic programs as well as epidemiological studies. Schizophrenic-specific symptomatology modification, need for hospitalization, significant change in care, disturbances in social behavior or suicide attempts were all used to define acute schizophrenic state. The decision to hospitalize is frequently used to define acute state but refers to multiple factors such as mood disorder, suicide attempts, drug abuse or social and environmental problems. Indeed, several and distinct definitions in a criteria basis form are available but no one has reached consensus. Because recognition of acute schizophrenic state remains based on the subjective clinician's advice, epidemiological and therapeutic studies fail in validity and reliability. The aim of the study was to evaluate how a population of French psychiatrists define criteria and therapeutic targets of acute schizophrenic state in their clinical practice. Psychiatrists filled out a self administered interview. At the time the interview was given, clinicians were notified that they were participating in a clinical consensus survey about schizophrenia. Six major indicators for acute state definition based on the literature data were proposed: general schizophrenic symptomatology modification (depression, anxiety, agitation, impulsivity/aggressiveness), specific schizophrenic symptomatology modification (positive symptoms, negative symptoms, disorganization), need for hospitalization, significant change in care, disturbance in social behavior and lastly, suicidal behavior. Minimal duration (1.2 or 4 weeks) of general and specific schizophrenic symptomatology modification required to define acute state were evaluated. The booklet included the 30 PANSS symptoms listed with their definitions. Among this symptom list, clinicians were instructed to select the ten criteria which they

FDG–PET–CT reduces the interobserver variability in rectal tumor delineation

International Nuclear Information System (INIS)

Buijsen, Jeroen; Bogaard, Jørgen van den; Weide, Hiska van der; Engelsman, Stephanie; Stiphout, Ruud van; Janssen, Marco; Beets, Geerard; Beets-Tan, Regina; Lambin, Philippe; Lammering, Guido

2012-01-01

Background and purpose: Previously, we showed a good correlation between pathology and an automatically generated PET-contour in rectal cancer. This study analyzed the effect of the use of PET–CT scan on the interobserver variation in GTV definition in rectal cancer and the influence of PET–CT on treatment volumes. Materials and methods: Forty two patients diagnosed with rectal cancer underwent an FDG–PET–CT for radiotherapy planning. An automatic contour was created on PET-scan using the source-to-background ratio. The GTV was delineated by 5 observers in 3 rounds: using CT and MRI, using CT, MRI and PET and using CT, MRI and PET auto-contour. GTV volumes were compared and concordance indices (CI) were calculated. Since the GTV is only a small portion of the treatment volume in rectal cancer, a separate analysis was performed to evaluate the influence of PET on the definition of the CTV used in daily clinical practice and the caudal extension of the treatment volumes. Results: GTV volumes based on PET were significantly smaller. CIs increased significantly using PET and the best interobserver agreement was observed using PET auto-contours. Furthermore, we found that in up to 29% of patients the CTV based on PET extended outside the CTV used in clinical practice. The caudal border of the treatment volume can be tailored using PET-scan in low seated tumors. Influence of PET on the position of the caudal border was most pronounced in high seated tumors. Conclusion: PET–CT increases the interobserver agreement in the GTV definition in rectal cancer, helps to avoid geographical misses and allows tailoring the caudal border of the treatment volume.

(18F) FDG PET/CT in patients with fever of unknown origin: AIIMS experience

International Nuclear Information System (INIS)

Nazar, A.H.; Naswa, N.; Ramya, S.; Patnecha, M.; Bangkim, Chandra K.H.; Kumar, R.; Bandopadhyay, G.P.; Bal, C.S.; Malhotra, A.

2010-01-01

Full text: The aim of this study was to assess the value of ( 18 F) FDG PET/CT in evaluation of patients with Fever of Unknown Origin (FUO). We retrospectively analysed clinical data and ( 18 F) FDG PET scan of 48 patients over a period of 1 year. These patients met the revised definition criteria of FUO (febrile illness of greater than 3 weeks duration, temperature greater than 38.3 C and no diagnosis after appropriate in-patient or out-patient evaluation). Most of the patients recruited in this study had normal clinical and radiological examination. ( 18 F) FDG PET was helpful in making a diagnosis in 24 patients. An infective/inflammatory cause of FUO was found in thirteen (27%) patients, a neoplasm in six (12.5%) patients, autoimmune cause in five (10.4%) patients. A definitive diagnosis could not be made in twenty four (50%) patients. Out of these 24 patients, 15 had normal PET/CT study, 9 had positive PET/CT findings but they lost in follow up and 2 died within 1 month of PET/CT study without any diagnosis. ( 18 F) FDG PET/CT is a useful tool for evaluation of patients with FUO. It provides important diagnostic clues not suggested by other conventional imaging modalities. Patients with positive PET/CT findings but no definitive diagnosis should be followed up further to improve utility of PET/CT

FDG PET/CT criteria for diagnosing mediastinal lymph node metastasis in patients with non-small cell lung cancer

International Nuclear Information System (INIS)

Cho, Y. S.; Choi, J. Y.; Lee, K. S.; Kwon, O. J.; Sim, Y. M.; Lee, S. J.; Hyun, S. H.; Lee, J. Y.; Lee, K. H.; Kim, B. T.

2007-01-01

We investigated the most accurate FDG PET/CT criteria using various PET and CT parameters for diagnosing metastatic mediastinal lymph nodes in patients with untreated NSCLC. Subjects were 178 consecutive patients with NSCLC undergoing PET/CT and surgical nodal staging. Diagnostic criteria of PET/CT for involvement of each mediastinal nodal station were max. SUV (mSUV), average SUV (aSUV), max. CT Hounsfield unit (mHU), average CT Hounsfield unit (aHU), and 5-point visual grading for CT attenuation; normal, suspicious/definite high attenuation (HA), partial/definite calcification (CAL). ROC curve analysis was done to assess the performance of each PET/CT criterion for detection of metastatic mediastinal nodal station. Of the pathologically examined 649 mediastinal nodal stations, 50 stations in 39 patients were proven to be malignant. The areas under curve (AUC) of ROC analysis for each criteria were 0.8882 (mSUV), 0.8875 (aSUV), 0.5668 (mHU), 0.5468 (aHU), and 0.4369 (VA), respectively. There were no malignant lymph nodes with increased FDG uptake having mHU > 120, aHU > 90, visually definite HA, or CAL. Using the benign criteria of mHU > 120, the AUCs of PET were significantly improved to 0.9233 (mSUV) and 0.9080 (aSUV), respectively (p 90, the AUCs of PET were improved to 0.8991 (mSUV, p 0.05), respectively. Using the benign criteria of visually definite HA or CAL, the AUCs of PET were significantly improved to 0.9094 (mSUV) and 0.9091 (aSUV), respectively (p 120, and visually definite HA or CAL can be used as PET/CT diagnostic criteria suggesting benign mediastinal lymph nodes in patients with NSCLC, irrespective of FDG uptake

Clinical applications of SPECT-CT

Energy Technology Data Exchange (ETDEWEB)

Ahmadzadehfar, Hojjat; Biersack, Hans-Juergen (eds.) [University Hospital Bonn (Germany). Dept. of Nuclear Medicine

2014-06-01

Covers the full spectrum of clinical applications of SPECT/CT in diagnosis of benign and malignant diseases. Includes chapters on the use of SPECT/CT for dosimetry and for therapy planning. Completely up to date. Many helpful illustrations. SPECT/CT cameras have considerably improved diagnostic accuracy in recent years. Such cameras allow direct correlation of anatomic and functional information, resulting in better localization and definition of scintigraphic findings. In addition to this anatomic referencing, CT coregistration provides superior quantification of radiotracer uptake based on the attenuation correction capabilities of CT. Useful applications of SPECT/CT have been identified not only in oncology but also in other specialties such as orthopedics and cardiology. This book covers the full spectrum of clinical applications of SPECT/CT in diagnosis and therapy planning of benign and malignant diseases. Opening chapters discuss the technology and physics of SPECT/CT and its use for dosimetry. The role of SPECT/CT in the imaging of a range of pathologic conditions is then addressed in detail. Applications covered include, among others, imaging of the thyroid, bone, and lungs, imaging of neuroendocrine tumors, cardiac scintigraphy, and sentinel node scintigraphy. Individual chapters are also devoted to therapy planning in selective internal radiation therapy of liver tumors and bremsstrahlung SPECT/CT. Readers will find this book to be an essential and up-to-date source of information on this invaluable hybrid imaging technique.

Space platform expendables resupply concept definition study. Volume 3: Work breakdown structure and work breakdown structure dictionary

Science.gov (United States)

1984-01-01

The work breakdown structure (WBS) for the Space Platform Expendables Resupply Concept Definition Study is described. The WBS consists of a list of WBS elements, a dictionary of element definitions, and an element logic diagram. The list and logic diagram identify the interrelationships of the elements. The dictionary defines the types of work that may be represented by or be classified under each specific element. The Space Platform Expendable Resupply WBS was selected mainly to support the program planning, scheduling, and costing performed in the programmatics task (task 3). The WBS is neither a statement-of-work nor a work authorization document. Rather, it is a framework around which to define requirements, plan effort, assign responsibilities, allocate and control resources, and report progress, expenditures, technical performance, and schedule performance. The WBS element definitions are independent of make-or-buy decisions, organizational structure, and activity locations unless exceptions are specifically stated.

Value of CT in the diagnosis of pseudomembranous colitis

International Nuclear Information System (INIS)

Fishman, E.K.; Merine, D.S.; Kuhlman, J.E.; Jones, B.

1989-01-01

With the increasing use of Ct as a primary imaging modality in the patient with abdominal distress, it is not surprising the CT may be the initial study to suggest the diagnosis of pseudomembranous colitis. The authors reviewed the CT scans in 16 patients with proved pseudomembranous colitis. In 12 of these cases, the diagnosis was not considered prior to CT. The CT findings included wall thickening (average, 18 mm), definite ulcerations (11 cases), ascites (two cases), and pseudoperforation (three cases). The pseudoperforation is caused by the trapping of contrast material within the large ulcerated mucosal folds and can simulate contrast extravasation. The various CT appearances of pseudomembranous colitis are addressed, as well as the potential difficulty in distinguishing it from other types of colitis

Post-treatment PET/CT and p16 status for predicting treatment outcomes in locally advanced head and neck cancer after definitive radiation

Energy Technology Data Exchange (ETDEWEB)

Awan, Musaddiq J.; Machtay, Mitchell; Yao, Min [Case Western Reserve University and University Hospitals, Department of Radiation Oncology, Cleveland, OH (United States); Lavertu, Pierre; Zender, Chad; Rezaee, Rod; Fowler, Nicole [University Hospitals, Department of Otolaryngology and Head and Neck Surgery, Cleveland, OH (United States); Karapetyan, Lilit; Gibson, Michael [University Hospitals, Department of Medical Oncology, Cleveland, OH (United States); Wasman, Jay [University Hospitals, Department of Pathology, Cleveland, OH (United States); Faulhaber, Peter [University Hospitals, Department of Nuclear Medicine and Radiology, Cleveland, OH (United States)

2017-06-15

To retrospectively review post-treatment (post-tx) FDG-PET/CT scans in patients with advanced head and neck squamous cell carcinoma (HNSCC) and known p16 status, treated with definitive (chemo)radiation (RT). A total of 108 eligible patients had N2A or greater HNSCC treated with chemoRT from August 1, 2008, to February 28, 2015, with post-tx PET/CT within 6 months after RT. Kaplan-Meier curves, log-rank statistics, and Cox proportional hazards regression were used for statistical analysis. Median follow-up was 2.38 years. Sixty-eight (63.0%) patients had p16+ and 40 (37.0%) had p16- status. Two-year overall survival and recurrence-free survival were 93.4% and 77.8%, respectively. The negative predictive value (NPV) of PET/CT for local recurrence (LR) was 100%. The NPV for regional recurrence (RR) was 96.5% for all patients, 100% for p16+ patients, and 88.5% for p16- patients. The positive predictive value (PPV) of PET/CT for recurrence was 77.3% for all patients, 50.0% for p16+, and 78.6% for p16-. The PPV for LR was 72.7% for all patients, 50.0% for p16+ patients, and 72.7% for p16- patients. The PPV for RR was 50.0% for all patients, 33% for p16+, and 66.6% for p16-. Post-tx PET/CT and p16 status were independent predictors of recurrence-free survival (p < 0.01). Post-tx PET/CT predicts treatment outcomes in both p16 + and p16- patients, and does so independently of p16 status. P16- patients with negative PET have a 10% risk of nodal recurrence, and closer follow-up in these patients is warranted. (orig.)

Linking Keystone Species and Functional Groups: A New Operational Definition of the Keystone Species Concept

OpenAIRE

Robert D. Davic

2003-01-01

The concept of the "keystone species" is redefined to allow for the a priori prediction of these species within ecosystems. A keystone species is held to be a strongly interacting species whose top-down effect on species diversity and competition is large relative to its biomass dominance within a functional group. This operational definition links the community importance of keystone species to a specific ecosystem process, e.g., the regulation of species diversity, within functional groups ...

Semantic similarity-based alignment between clinical archetypes and SNOMED CT: an application to observations.

Science.gov (United States)

Meizoso García, María; Iglesias Allones, José Luis; Martínez Hernández, Diego; Taboada Iglesias, María Jesús

2012-08-01

One of the main challenges of eHealth is semantic interoperability of health systems. But, this will only be possible if the capture, representation and access of patient data is standardized. Clinical data models, such as OpenEHR Archetypes, define data structures that are agreed by experts to ensure the accuracy of health information. In addition, they provide an option to normalize clinical data by means of binding terms used in the model definition to standard medical vocabularies. Nevertheless, the effort needed to establish the association between archetype terms and standard terminology concepts is considerable. Therefore, the purpose of this study is to provide an automated approach to bind OpenEHR archetypes terms to the external terminology SNOMED CT, with the capability to do it at a semantic level. This research uses lexical techniques and external terminological tools in combination with context-based techniques, which use information about structural and semantic proximity to identify similarities between terms and so, to find alignments between them. The proposed approach exploits both the structural context of archetypes and the terminology context, in which concepts are logically defined through the relationships (hierarchical and definitional) to other concepts. A set of 25 OBSERVATION archetypes with 477 bound terms was used to test the method. Of these, 342 terms (74.6%) were linked with 96.1% precision, 71.7% recall and 1.23 SNOMED CT concepts on average for each mapping. It has been detected that about one third of the archetype clinical information is grouped logically. Context-based techniques take advantage of this to increase the recall and to validate a 30.4% of the bindings produced by lexical techniques. This research shows that it is possible to automatically map archetype terms to a standard terminology with a high precision and recall, with the help of appropriate contextual and semantic information of both models. Moreover, the

Proposal for a universal definition of cerebral infarction.

Science.gov (United States)

Saver, Jeffrey L

2008-11-01

Cerebral infarction is a leading cause of disability and death worldwide but has no uniform international definition. Recent diagnostic advances have revised fundamental concepts in cerebral and cardiac ischemia. Cardiologists, already possessed of a nosologic framework distinguishing myocardial infarction from unstable angina on the basis of tissue state, promulgated a new "universal" tissue definition of myocardial infarction incorporating insights afforded by assays of cardiac troponin, a serum biomarker exquisitely sensitive to myocardial injury. Concurrently, vascular neurologists proposed a new tissue, rather than time, criterion to distinguish transient ischemia attack from cerebral infarction, responding to perspectives provided by diffusion MRI and cerebral blood volume CT, imaging biomarkers highly sensitive to neuronal injury. To complete this conceptual realignment, vascular neurology must now advance a clear, uniform, and operationalizable tissue definition of cerebral infarction. This review proposes cerebral infarction be defined as brain or retinal cell death due to prolonged ischemia. This definition categorizes both pannecrosis and neuronal dropout ("complete" and "incomplete" infarcts in classic neuropathologic terminology) as cerebral infarcts. Making the presence of any neuronal or glial cell death essential yields a definition of cerebral infarction that has high relevance to patients, physicians, and policymakers; is more easily applied in clinical practice; fosters action in acute care; harmonizes with myocardial ischemia classification; and focuses diagnostic evaluation on the cause of brain ischemia and the occurrence of end organ injury. The term cerebral infarction should be used when there is evidence of brain or retinal cell death due to cerebral ischemia.

Retractile mesenteritis in a 12-year-old girl: CT findings

International Nuclear Information System (INIS)

Ueda, D.; Chiba, S.

1997-01-01

We report a pathologically proven case of retractile mesenteritis in a 12-year-old girl. Computed tomography (CT) demonstrated a large mass of fat density completely circumscribing the colon. Although the definitive diagnosis of retractile mesenteritis depends on histopathological findings, recognition of CT features is helpful in the diagnosis. (orig.). With 1 fig

Standardizing terms, definitions and concepts for describing and interpreting unwanted immunogenicity of biopharmaceuticals: recommendations of the Innovative Medicines Initiative ABIRISK consortium.

Science.gov (United States)

Rup, B; Pallardy, M; Sikkema, D; Albert, T; Allez, M; Broet, P; Carini, C; Creeke, P; Davidson, J; De Vries, N; Finco, D; Fogdell-Hahn, A; Havrdova, E; Hincelin-Mery, A; C Holland, M; H Jensen, P E; Jury, E C; Kirby, H; Kramer, D; Lacroix-Desmazes, S; Legrand, J; Maggi, E; Maillère, B; Mariette, X; Mauri, C; Mikol, V; Mulleman, D; Oldenburg, J; Paintaud, G; R Pedersen, C; Ruperto, N; Seitz, R; Spindeldreher, S; Deisenhammer, F

2015-09-01

Biopharmaceuticals (BPs) represent a rapidly growing class of approved and investigational drug therapies that is contributing significantly to advancing treatment in multiple disease areas, including inflammatory and autoimmune diseases, genetic deficiencies and cancer. Unfortunately, unwanted immunogenic responses to BPs, in particular those affecting clinical safety or efficacy, remain among the most common negative effects associated with this important class of drugs. To manage and reduce risk of unwanted immunogenicity, diverse communities of clinicians, pharmaceutical industry and academic scientists are involved in: interpretation and management of clinical and biological outcomes of BP immunogenicity, improvement of methods for describing, predicting and mitigating immunogenicity risk and elucidation of underlying causes. Collaboration and alignment of efforts across these communities is made difficult due to lack of agreement on concepts, practices and standardized terms and definitions related to immunogenicity. The Innovative Medicines Initiative (IMI; www.imi-europe.org), ABIRISK consortium [Anti-Biopharmaceutical (BP) Immunization Prediction and Clinical Relevance to Reduce the Risk; www.abirisk.eu] was formed by leading clinicians, academic scientists and EFPIA (European Federation of Pharmaceutical Industries and Associations) members to elucidate underlying causes, improve methods for immunogenicity prediction and mitigation and establish common definitions around terms and concepts related to immunogenicity. These efforts are expected to facilitate broader collaborations and lead to new guidelines for managing immunogenicity. To support alignment, an overview of concepts behind the set of key terms and definitions adopted to date by ABIRISK is provided herein along with a link to access and download the ABIRISK terms and definitions and provide comments (http://www.abirisk.eu/index_t_and_d.asp). © 2015 British Society for Immunology.

Radiation exposure in CT-guided interventions

Energy Technology Data Exchange (ETDEWEB)

Kloeckner, Roman, E-mail: Roman.Kloeckner@unimedizin-mainz.de [Department of Diagnostic and Interventional Radiology, Johannes Gutenberg-University, Langenbeckstraße 1, 55131 Mainz (Germany); Santos, Daniel Pinto dos; Schneider, Jens [Department of Diagnostic and Interventional Radiology, Johannes Gutenberg-University, Langenbeckstraße 1, 55131 Mainz (Germany); Kara, Levent [Department of Radiology, Inselspital Bern, Freiburgstraße 18, 3010 Bern (Switzerland); Dueber, Christoph; Pitton, Michael B. [Department of Diagnostic and Interventional Radiology, Johannes Gutenberg-University, Langenbeckstraße 1, 55131 Mainz (Germany)

2013-12-01

Purpose: To investigate radiation exposure in computed tomography (CT)-guided interventions, to establish reference levels for exposure, and to discuss strategies for dose reduction. Materials and methods: We analyzed 1576 consecutive CT-guided procedures in 1284 patients performed over 4.5 years, including drainage placements; biopsies of different organs; radiofrequency and microwave ablations (RFA/MWA) of liver, bone, and lung tumors; pain blockages, and vertebroplasties. Data were analyzed with respect to scanner settings, overall radiation doses, and individual doses of planning CT series, CT intervention, and control CT series. Results: Eighy-five percent of the total radiation dose was applied during the pre- and post-interventional CT series, leaving only 15% applied by the CT-guided intervention itself. Single slice acquisition was associated with lower doses than continuous CT-fluoroscopy (37 mGy cm vs. 153 mGy cm, p < 0.001). The third quartile of radiation doses varied considerably for different interventions. The highest doses were observed in complex interventions like RFA/MWA of the liver, followed by vertebroplasty and RFA/MWA of the lung. Conclusions: This paper suggests preliminary reference levels for various intervention types and discusses strategies for dose reduction. A multicenter registry of radiation exposure including a broader spectrum of scanners and intervention types is needed to develop definitive reference levels.

Optimal gross tumor volume definition in lung-sparing intensity modulated radiotherapy for pleural mesothelioma: an in silico study.

Science.gov (United States)

Botticella, Angela; Defraene, Gilles; Nackaerts, Kristiaan; Deroose, Christophe M; Coolen, Johan; Nafteux, Philippe; Peeters, Stephanie; Ricardi, Umberto; De Ruysscher, Dirk

2016-12-01

The gross tumor volume (GTV) definition for malignant pleural mesothelioma (MPM) is ill-defined. We therefore investigated which imaging modality is optimal: computed tomography (CT) with intravenous contrast (IVC), positron emission tomography-CT (PET/CT) or magnetic resonance imaging (MRI). Sixteen consecutive patients with untreated stage I-IV MPM were included. Patients with prior pleurodesis were excluded. CT with IVC, 18FDG-PET/CT and MRI (T2 and contrast-enhanced T1) were obtained. CT was rigidly co-registered with PET/CT and with MRI. Three sets of pleural GTVs were defined: GTV CT , GTV CT+PET/CT and GTV CT+MRI . Quantitative and qualitative evaluations of the contoured GTVs were performed. Compared to CT-based GTV definition, PET/CT identified additional tumor sites (defined as either separate nodules or greater extent of a known tumor) in 12/16 patients. Compared to either CT or PET/CT, MRI identified additional tumor sites in 15/16 patients (p = .7). The mean GTV CT , GTV CT+PET/CT and GTV CT+MRI [±standard deviation (SD)] were 630.1 cm 3 (±302.81), 640.23 cm 3 (±302.83) and 660.8 cm 3 (±290.8), respectively. Differences in mean volumes were not significant. The mean Jaccard Index was significantly lower in MRI-based contours versus all the others. As MRI identified additional pleural disease sites in the majority of patients, it may play a role in optimal target volume definition.

Multidetector CT in children: current concepts and dose reduction strategies

Energy Technology Data Exchange (ETDEWEB)

Nievelstein, Rutger A.J.; Dam, Ingrid M. van [University Medical Centre Utrecht, Department of Pediatric Radiology, Wilhelmina Children' s Hospital, E01.132, P.O. Box 85500, Utrecht (Netherlands); Molen, Aart J. van der [Leiden University Medical Centre, Department of Radiology, C-2S, Leiden (Netherlands)

2010-08-15

The recent technical development of multidetector CT (MDCT) has contributed to a substantial increase in its diagnostic applications and accuracy in children. A major drawback of MDCT is the use of ionising radiation with the risk of inducing secondary cancer. Therefore, justification and optimisation of paediatric MDCT is of great importance in order to minimise these risks (''as low as reasonably achievable'' principle). This review will focus on all technical and non-technical aspects relevant for paediatric MDCT optimisation and includes guidelines for radiation dose level-based CT protocols. (orig.)

Multidetector CT in children: current concepts and dose reduction strategies

International Nuclear Information System (INIS)

Nievelstein, Rutger A.J.; Dam, Ingrid M. van; Molen, Aart J. van der

2010-01-01

The recent technical development of multidetector CT (MDCT) has contributed to a substantial increase in its diagnostic applications and accuracy in children. A major drawback of MDCT is the use of ionising radiation with the risk of inducing secondary cancer. Therefore, justification and optimisation of paediatric MDCT is of great importance in order to minimise these risks (''as low as reasonably achievable'' principle). This review will focus on all technical and non-technical aspects relevant for paediatric MDCT optimisation and includes guidelines for radiation dose level-based CT protocols. (orig.)

Indeterminate findings on oncologic PET/CT: What difference dose PET/MRI make?

Energy Technology Data Exchange (ETDEWEB)

Fraum, Tyler J.; Fowler, Kathryn J.; McConathy, Jonathan; Dehdashti, Farokh [Mallinckrodt Institute of Radiology, Washington University School of Medicine, Saint Louis (United States)

2016-12-15

Positron emission tomography/computed tomography (PET/CT) with 2-deoxy-2-[{sup 18}F]fluoro-D-glucose (FDG) has become the standard of care for the initial staging and subsequent treatment response assessment of many different malignancies. Despite this success, PET/CT is often supplemented by MRI to improve assessment of local tumor invasion and to facilitate detection of lesions in organs with high background FDG uptake. Consequently, PET/MRI has the potential to expand the clinical value of PET examinations by increasing reader certainty and reducing the need for subsequent imaging. This study evaluates the ability of FDG-PET/MRI to clarify findings initially deemed indeterminate on clinical FDG-PET/CT studies. A total of 190 oncology patients underwent whole-body PET/CT, immediately followed by PET/MRI utilizing the same FDG administration. Each PET/CT was interpreted by our institution's nuclear medicine service as a standard-of-care clinical examination. Review of these PET/CT reports identified 31 patients (16 %) with indeterminate findings. Two readers evaluated all 31 PET/CT studies, followed by the corresponding PET/MRI studies. A consensus was reached for each case, and changes in interpretation directly resulting from PET/MRI review were recorded. Interpretations were then correlated with follow-up imaging, pathology results, and other diagnostic studies. In 18 of 31 cases with indeterminate findings on PET/CT, PET/MRI resulted in a more definitive interpretation by facilitating the differentiation of infection/inflammation from malignancy (15/18), the accurate localization of FDG-avid lesions (2/18), and the characterization of incidental non-FDG-avid solid organ lesions (1/18). Explanations for improved reader certainty with PET/MRI included the superior soft tissue contrast of MRI and the ability to assess cellular density with diffusion-weighted imaging. The majority (12/18) of such cases had an appropriate standard of reference; in all 12 cases

Indeterminate findings on oncologic PET/CT: What difference dose PET/MRI make?

International Nuclear Information System (INIS)

Fraum, Tyler J.; Fowler, Kathryn J.; McConathy, Jonathan; Dehdashti, Farokh

2016-01-01

Positron emission tomography/computed tomography (PET/CT) with 2-deoxy-2-["1"8F]fluoro-D-glucose (FDG) has become the standard of care for the initial staging and subsequent treatment response assessment of many different malignancies. Despite this success, PET/CT is often supplemented by MRI to improve assessment of local tumor invasion and to facilitate detection of lesions in organs with high background FDG uptake. Consequently, PET/MRI has the potential to expand the clinical value of PET examinations by increasing reader certainty and reducing the need for subsequent imaging. This study evaluates the ability of FDG-PET/MRI to clarify findings initially deemed indeterminate on clinical FDG-PET/CT studies. A total of 190 oncology patients underwent whole-body PET/CT, immediately followed by PET/MRI utilizing the same FDG administration. Each PET/CT was interpreted by our institution's nuclear medicine service as a standard-of-care clinical examination. Review of these PET/CT reports identified 31 patients (16 %) with indeterminate findings. Two readers evaluated all 31 PET/CT studies, followed by the corresponding PET/MRI studies. A consensus was reached for each case, and changes in interpretation directly resulting from PET/MRI review were recorded. Interpretations were then correlated with follow-up imaging, pathology results, and other diagnostic studies. In 18 of 31 cases with indeterminate findings on PET/CT, PET/MRI resulted in a more definitive interpretation by facilitating the differentiation of infection/inflammation from malignancy (15/18), the accurate localization of FDG-avid lesions (2/18), and the characterization of incidental non-FDG-avid solid organ lesions (1/18). Explanations for improved reader certainty with PET/MRI included the superior soft tissue contrast of MRI and the ability to assess cellular density with diffusion-weighted imaging. The majority (12/18) of such cases had an appropriate standard of reference; in all 12 cases, the

PET/CT Based Dose Planning in Radiotherapy

DEFF Research Database (Denmark)

Berthelsen, Anne Kiil; Jakobsen, Annika Loft; Sapru, Wendy

2011-01-01

radiotherapy planning with PET/CT prior to the treatment. The PET/CT, including the radiotherapy planning process as well as the radiotherapy process, is outlined in detail. The demanding collaboration between mould technicians, nuclear medicine physicians and technologists, radiologists and radiology......This mini-review describes how to perform PET/CT based radiotherapy dose planning and the advantages and possibilities obtained with the technique for radiation therapy. Our own experience since 2002 is briefly summarized from more than 2,500 patients with various malignant diseases undergoing...... technologists, radiation oncologists, physicists, and dosimetrists is emphasized. We strongly believe that PET/CT based radiotherapy planning will improve the therapeutic output in terms of target definition and non-target avoidance and will play an important role in future therapeutic interventions in many...

PET/CT-guided interventional procedures: rationale, justification, initial study, and research plan

Energy Technology Data Exchange (ETDEWEB)

Wong, K.; Rahill, J.; Cleary, K. [Computer Aided Interventions and Medical Robotics (CAIMR), Imaging Science and Information Systems (ISIS) Center, Georgetown Univ. Medical Center, Washington, DC (United States); Petrillo, S.; Earl-Graef, D. [Dept. of Radiology, Georgetown Univ. Hospital, MedStar Health, Washington, DC (United States); Banovac, F.; Levy, E. [Computer Aided Interventions and Medical Robotics (CAIMR), Imaging Science and Information Systems (ISIS) Center, Georgetown Univ. Medical Center, Washington, DC (United States); Dept. of Radiology, Georgetown Univ. Hospital, MedStar Health, Washington, DC (United States); Shekhar, R. [Dept. of Radiology, Univ. of Maryland Medical Center, Baltimore, MD (United States)

2007-06-15

Positron-emission tomography (PET) and PET/CT (computed tomography) are becoming increasingly important for diagnosis and treatment of cancer. Clinically relevant changes can sometimes be seen on PET that are not seen on other imaging modalities. However, PET is not suitable for guiding biopsy as the images are not obtained in real-time. Therefore, our research group has begun developing a concept for PET/CT-guided interventional procedures. This paper presents the rationale for this concept, outlines our research plan, and includes an initial study to evaluate the relative sensitivity of CT and PET/CT in detecting suspicious lesions. (orig.)

The meaning and knowledge of definition in elementary school geometry

OpenAIRE

Tomažič, Maša

2017-01-01

The first part of the diploma thesis considers the theoretical aspects of the meaning of concepts and definition of concepts. The focus is on the question ‘Why are definitions important and how should definitions look like?’. Then, the difference between the definition of a concept and the image of a concept is explained and the interactions between them considered. The second part of this diploma thesis describes the results of a pilot study, which considered the extent to which seventh...

Definition of the prostate in CT and MRI: a multi-observer study

NARCIS (Netherlands)

Rasch, C.; Barillot, I.; Remeijer, P.; Touw, A.; van Herk, M.; Lebesque, J. V.

1999-01-01

To determine, in three-dimensions, the difference between prostate delineation in magnetic resonance (MR) and computer tomography (CT) images for radiotherapy treatment planning. Three radiation oncologists, considered experts in the field, outlined the prostate without seminal vesicles both on CT,

Definition of postlumpectomy tumor bed for radiotherapy boost field planning: CT versus surgical clips

International Nuclear Information System (INIS)

Goldberg, Hadassah; Prosnitz, Robert G.; Olson, John A.; Marks, Lawrence B.

2005-01-01

Purpose: To compare the location and extent of the tumor bed as defined by surgical clips and computed tomography (CT) scans, after lumpectomy, for electron boost planning as part of breast radiotherapy. Methods and Materials: Planning CT images of 31 operated breasts in 30 patients who underwent lumpectomy were reviewed. One or more clips were placed in the lumpectomy cavity. Serial CT images were used to measure the depth and transverse and longitudinal dimensions. The area and geometric center of the tumor bed were defined by the clips and CT. Results: The CT and clip measurements were identical for the maximal tumor depth in 27 of 30 patients. The CT bed extended beyond the clips by 0-7 mm medially in the transverse/longitudinal extent (multiclip patients). The median distance between the geometric centers in the coronal plane for the tumor bed center was larger for patients with single clips than for those with multiple clips (p 2 . The CT bed was more readily visible in patients with a shorter interval between surgery and radiotherapy. Conclusion: The maximal depth of the tumor bed was similar using the two methods. The extent and centers of the clip-and CT-determined beds differed significantly. This may indicate an underestimation of the tumor bed as defined by clips only and justifies integration of CT information in boost field planning

Evaluation of the role of 18FDG-PET/CT in radiotherapy target definition in patients with head and neck cancer

Energy Technology Data Exchange (ETDEWEB)

Newbold, Katie L; Partridge, Mike; Cook, Gary; Sharma, Bhupinder; Rhys-Evans, Peter; Harrington, Kevin J; Nutting, Christopher M [The Royal Marsden NHS Foundation Trust, Sutton, Surrey (United Kingdom)

2008-08-15

Background and purpose. As techniques for radiotherapy delivery have developed, increasingly accurate localisation of disease is demanded. Functional imaging, particularly PET and its fusion with anatomical modalities, such as PET/CT, promises to improve detection and characterisation of disease. This study evaluated the impact of 18FDG-PET/CT on radiotherapy target volume definition in head and neck cancer (HNC). Materials and methods. The PET/CT scans of patients with HNC were used in a radiotherapy planning (RTP) study. The gross tumour volume (GTV), clinical target volume (CTV) and planning target volume (PTV) were defined conventionally and compared to those defined using the PET/CT. Data were reported as the median value with 95% confidence intervals. Results. Eighteen patients were consented, 9 had known primary tumour site, 9 presented as unknown primary. In nine cases where the primary site was known, the combined primary and nodal GTV (GTVp+n) increased by a median of 6.1cm3 (2.6, 12.2) or 78% (18, 313), p=0.008 with CTV increasing by a median of 10.1cm3 (1.3, 30.6) or 4% (0, 13) p=0.012. In 9 cases of unknown primary the GTVp+n increased by a median 6.3cm3 (0.2, 15.7) or 61% (4, 210), p=0.012, with CTV increasing by a median 155.4cm3 (2.7, 281.7) or 95% (1, 137), p=0.008. Conclusion. 18FDG-PET revealed disease lying outside the conventional target volume, either extending a known area or highlighting a previously unknown area of disease, including the primary tumour in 5 cases. We recommend PET/CT in the RTP of all cases of unknown primary. In patients with a known primary, although the change in volume was statistically significant the clinical impact is less clear. 18FDG-PET can also show areas within the conventional target volume that are hypermetabolic which may be possible biological target volumes for dose escalation studies in the future

A Contribution to the Definition of the Concept of Popular Culture: An Empirical Inquiry into the Epistemological Shortcomings of Popular Conceptions about Pretrial Detention in Serbia

Directory of Open Access Journals (Sweden)

Saša Nedeljković

2016-02-01

Full Text Available In an attempt to ascertain the functionality of certain definitions of the concept of popular culture, or rather, to point out certain methodological options for the study of popular culture through analyzing certain popular conceptions, I have sought out those areas of social life which are under-represented in popular culture. I consider their avoidance symptomatic, worthy of attention and suitable for analysis. Discovering pretrial confinement as one such neglected area or topic, and trying to indirectly discover what might be the cause of this, I have analyzed and systematized those of its characteristics and elements which do not fulfill the requirements of the syndrome of popularity as it is typically understood.

Pediatric CT quality management and improvement program

International Nuclear Information System (INIS)

Larson, David B.; Chan, Frandics P.; Newman, Beverley; Fleischmann, Dominik; Molvin, Lior Z.; Wang, Jia

2014-01-01

Modern CT is a powerful yet increasingly complex technology that continues to rapidly evolve; optimal clinical implementation as well as appropriate quality management and improvement in CT are challenging but attainable. This article outlines the organizational structure on which a CT quality management and improvement program can be built, followed by a discussion of common as well as pediatric-specific challenges. Organizational elements of a CT quality management and improvement program include the formulation of clear objectives; definition of the roles and responsibilities of key personnel; implementation of a technologist training, coaching and feedback program; and use of an efficient and accurate monitoring system. Key personnel and roles include a radiologist as the CT director, a qualified CT medical physicist, as well as technologists with specific responsibilities and adequate time dedicated to operation management, CT protocol management and CT technologist education. Common challenges in managing a clinical CT operation are related to the complexity of newly introduced technology, of training and communication and of performance monitoring. Challenges specific to pediatric patients include the importance of including patient size in protocol and dose considerations, a lower tolerance for error in these patients, and a smaller sample size from which to learn and improve. (orig.)

Pediatric CT quality management and improvement program

Energy Technology Data Exchange (ETDEWEB)

Larson, David B.; Chan, Frandics P.; Newman, Beverley; Fleischmann, Dominik [Stanford University School of Medicine, Department of Radiology, Stanford, CA (United States); Molvin, Lior Z. [Stanford Hospital and Clinics, Stanford, CA (United States); Wang, Jia [Stanford University, Environmental Health and Safety, Stanford, CA (United States)

2014-10-15

Modern CT is a powerful yet increasingly complex technology that continues to rapidly evolve; optimal clinical implementation as well as appropriate quality management and improvement in CT are challenging but attainable. This article outlines the organizational structure on which a CT quality management and improvement program can be built, followed by a discussion of common as well as pediatric-specific challenges. Organizational elements of a CT quality management and improvement program include the formulation of clear objectives; definition of the roles and responsibilities of key personnel; implementation of a technologist training, coaching and feedback program; and use of an efficient and accurate monitoring system. Key personnel and roles include a radiologist as the CT director, a qualified CT medical physicist, as well as technologists with specific responsibilities and adequate time dedicated to operation management, CT protocol management and CT technologist education. Common challenges in managing a clinical CT operation are related to the complexity of newly introduced technology, of training and communication and of performance monitoring. Challenges specific to pediatric patients include the importance of including patient size in protocol and dose considerations, a lower tolerance for error in these patients, and a smaller sample size from which to learn and improve. (orig.)

Infrastructure: concept, types and value

Directory of Open Access Journals (Sweden)

Alexander E. Lantsov

2013-01-01

Full Text Available Researches of influence of infrastructure on the economic growth and development of the countries gained currency. However the majority of authors drop the problem of definition of accurate concept of studied object and its criteria out. In the given article various approaches in the definition of «infrastructure» concept, criterion and the characteristics of infrastructure distinguishing it from other capital assets are presented. Such types of infrastructure, as personal, institutional, material, production, social, etc. are considered. Author’s definition of infrastructure is given.

Quality Assurance of UMLS Semantic Type Assignments Using SNOMED CT Hierarchies.

Science.gov (United States)

Gu, H; Chen, Y; He, Z; Halper, M; Chen, L

2016-01-01

The Unified Medical Language System (UMLS) is one of the largest biomedical terminological systems, with over 2.5 million concepts in its Metathesaurus repository. The UMLS's Semantic Network (SN) with its collection of 133 high-level semantic types serves as an abstraction layer on top of the Metathesaurus. In particular, the SN elaborates an aspect of the Metathesaurus's concepts via the assignment of one or more types to each concept. Due to the scope and complexity of the Metathesaurus, errors are all but inevitable in this semantic-type assignment process. To develop a semi-automated methodology to help assure the quality of semantic-type assignments within the UMLS. The methodology uses a cross-validation strategy involving SNOMED CT's hierarchies in combination with UMLS semantic types. Semantically uniform, disjoint concept groups are generated programmatically by partitioning the collection of all concepts in the same SNOMED CT hierarchy according to their respective semantic-type assignments in the UMLS. Domain experts are then called upon to review the concepts in any group having a small number of concepts. It is our hypothesis that a semantic-type assignment combination applicable only to a very small number of concepts in a SNOMED CT hierarchy is an indicator of potential problems. The methodology was applied to the UMLS 2013AA release along with the SNOMED CT from January 2013. An overall error rate of 33% was found for concepts proposed by the quality-assurance methodology. Supporting our hypothesis, that number was four times higher than the error rate found in control samples. The results show that the quality-assurance methodology can aid in effective and efficient identification of UMLS semantic-type assignment errors.

Organic food quality: a framework for concept, definition and evaluation from the European perspective.

Science.gov (United States)

Kahl, Johannes; Baars, Ton; Bügel, Susanne; Busscher, Nicolaas; Huber, Machteld; Kusche, Daniel; Rembiałkowska, Ewa; Schmid, Otto; Seidel, Kathrin; Taupier-Letage, Bruno; Velimirov, Alberta; Załecka, Aneta

2012-11-01

Consumers buy organic food because they believe in the high quality of the product. Furthermore, the EU legal regulatory framework for organic food and farming defines high quality of the products as an important goal of production. A major challenge is the need to define food quality concepts and methods for determination. A background is described which allows embedding of the quality definitions as well as evaluation methods into a conceptual framework connected to the vision and mission of organic agriculture and food production. Organic food quality is defined through specific aspects and criteria. For evaluation each criterion has to be described by indicators. The determination of indicators should be through parameters, where parameters are described by methods. Conversely, the conceptual framework is described according to underlying principles and starting definitions are given, but further work has do be done on the detailed scientific description of the indicators. Furthermore, parameters have to be defined for the evaluation of suitability of these indicators for organic food production. Copyright © 2012 Society of Chemical Industry.

Concept definition for space station technology development experiments. Experiment definition, task 2

Science.gov (United States)

1986-01-01

The second task of a study with the overall objective of providing a conceptual definition of the Technology Development Mission Experiments proposed by LaRC on space station is discussed. During this task, the information (goals, objectives, and experiment functional description) assembled on a previous task was translated into the actual experiment definition. Although still of a preliminary nature, aspects such as: environment, sensors, data acquisition, communications, handling, control telemetry requirements, crew activities, etc., were addressed. Sketches, diagrams, block diagrams, and timeline analyses of crew activities are included where appropriate.

Critical thinking: concept analysis from the perspective of Rodger's evolutionary method of concept analysis

Directory of Open Access Journals (Sweden)

Fábio da Costa Carbogim

Full Text Available ABSTRACT Objective: to analyze the concept of critical thinking (CT in Rodger's evolutionary perspective. Method: documentary research undertaken in the Cinahl, Lilacs, Bdenf and Dedalus databases, using the keywords of 'critical thinking' and 'Nursing', without limitation based on year of publication. The data were analyzed in accordance with the stages of Rodger's conceptual model. The following were included: books and articles in full, published in Portuguese, English or Spanish, which addressed CT in the teaching and practice of Nursing; articles which did not address aspects related to the concept of CT were excluded. Results: the sample was made up of 42 works. As a substitute term, emphasis is placed on 'analytical thinking', and, as a related factor, decision-making. In order, the most frequent preceding and consequent attributes were: ability to analyze, training of the student nurse, and clinical decision-making. As the implications of CT, emphasis is placed on achieving effective results in care for the patient, family and community. Conclusion: CT is a cognitive skill which involves analysis, logical reasoning and clinical judgment, geared towards the resolution of problems, and standing out in the training and practice of the nurse with a view to accurate clinical decision-making and the achieving of effective results.

Evolutionary space platform concept study. Volume 2, part B: Manned space platform concepts

Science.gov (United States)

1982-01-01

Logical, cost-effective steps in the evolution of manned space platforms are investigated and assessed. Tasks included the analysis of requirements for a manned space platform, identifying alternative concepts, performing system analysis and definition of the concepts, comparing the concepts and performing programmatic analysis for a reference concept.

TH-C-BRD-06: A Novel MRI Based CT Artifact Correction Method for Improving Proton Range Calculation in the Presence of Severe CT Artifacts

International Nuclear Information System (INIS)

Park, P; Schreibmann, E; Fox, T; Roper, J; Elder, E; Tejani, M; Crocker, I; Curran, W; Dhabaan, A

2014-01-01

Purpose: Severe CT artifacts can impair our ability to accurately calculate proton range thereby resulting in a clinically unacceptable treatment plan. In this work, we investigated a novel CT artifact correction method based on a coregistered MRI and investigated its ability to estimate CT HU and proton range in the presence of severe CT artifacts. Methods: The proposed method corrects corrupted CT data using a coregistered MRI to guide the mapping of CT values from a nearby artifact-free region. First patient MRI and CT images were registered using 3D deformable image registration software based on B-spline and mutual information. The CT slice with severe artifacts was selected as well as a nearby slice free of artifacts (e.g. 1cm away from the artifact). The two sets of paired MRI and CT images at different slice locations were further registered by applying 2D deformable image registration. Based on the artifact free paired MRI and CT images, a comprehensive geospatial analysis was performed to predict the correct CT HU of the CT image with severe artifact. For a proof of concept, a known artifact was introduced that changed the ground truth CT HU value up to 30% and up to 5cm error in proton range. The ability of the proposed method to recover the ground truth was quantified using a selected head and neck case. Results: A significant improvement in image quality was observed visually. Our proof of concept study showed that 90% of area that had 30% errors in CT HU was corrected to 3% of its ground truth value. Furthermore, the maximum proton range error up to 5cm was reduced to 4mm error. Conclusion: MRI based CT artifact correction method can improve CT image quality and proton range calculation for patients with severe CT artifacts

Ecological units: definitions and application.

Science.gov (United States)

Jax, Kurt

2006-09-01

Concepts of ecological units, such as population, community, and ecosystem, are at the basis of ecological theory and research and have increasingly become the focus of conservation strategies. Concepts of these units still suffer from inconsistencies and confusions over terminology. The different concepts are treated here together as a common "conceptual cluster," with similar ecological functions (roles) and similar problems in their definition and use. An analysis of the multitude of existing terms and concepts that have been developed for these units reveals that they differ with respect to at least four basic criteria: (i) the questions as to whether they are defined statistically or via a network of interactions; (ii) if their boundaries are drawn by topographical or process-related criteria; (iii) how high the required internal relationships are; and (iv) if they are perceived as "real" entities or abstractions by an observer The various definitions cannot be easily sorted into just a few types, but they can be characterized by several independent criteria. I argue that serious problems arise if the different possibilities of defining ecological units are not recognized and if the concepts are perceived as self-evident. The different concepts of ecological units should be defined and used in a philosophically informed manner I propose a dual approach to the use of ecological units. Generic meanings of the main concepts (especially population, community, and ecosystem) should be retained only as heuristically useful perspectives, while specific and "operational" definitions of the concepts as units should be developed, depending on specific purposes of their use. Some thoughts on the basic requirements for such definitions and the domains of their uses are briefly explained.

The sensitivity of computed tomography (CT) scans in detecting trauma: are CT scans reliable enough for courtroom testimony?

Science.gov (United States)

Molina, D Kimberley; Nichols, Joanna J; Dimaio, Vincent J M

2007-09-01

Rapid and accurate recognition of traumatic injuries is extremely important in emergency room and surgical settings. Emergency departments depend on computed tomography (CT) scans to provide rapid, accurate injury assessment. We conducted an analysis of all traumatic deaths autopsied at the Bexar County Medical Examiner's Office in which perimortem medical imaging (CT scan) was performed to assess the reliability of the CT scan in detecting trauma with sufficient accuracy for courtroom testimony. Cases were included in the study if an autopsy was conducted, a CT scan was performed within 24 hours before death, and there was no surgical intervention. Analysis was performed to assess the correlation between the autopsy and CT scan results. Sensitivity, specificity, positive predictive value, and negative predictive value were defined for the CT scan based on the autopsy results. The sensitivity of the CT scan ranged from 0% for cerebral lacerations, cervical vertebral body fractures, cardiac injury, and hollow viscus injury to 75% for liver injury. This study reveals that CT scans are an inadequate detection tool for forensic pathologists, where a definitive diagnosis is required, because they have a low level of accuracy in detecting traumatic injuries. CT scans may be adequate for clinicians in the emergency room setting, but are inadequate for courtroom testimony. If the evidence of trauma is based solely on CT scan reports, there is a high possibility of erroneous accusations, indictments, and convictions.

Dual, use-based definition of "system"

CSIR Research Space (South Africa)

Gonçalves, DP

2015-09-01

Full Text Available The standard definition (ISO 15288, 2008) of the concept of a system is not complete and is the definition of a closed system. Such a definition is inadequate for systems engineering. A use-based definition is proposed which spans the open...

Translational research: a concept analysis.

Science.gov (United States)

Wendler, M Cecilia; Kirkbride, Geri; Wade, Kristen; Ferrell, Lynne

2013-01-01

BACKGROUND/CONCEPTUAL FRAMEWORK: Little is known about which approaches facilitate adoption and sustainment of evidence-based practice change in the highly complex care environments that constitute clinical practice today. The purpose of this article was to complete a concept analysis of translational research using a modified Walker and Avant approach. DESIGN/DATA COLLECTION: Using a rigorous and thorough review of the recent health care literature generated by a deep electronic search from 2004-2011, 85 appropriate documents were retrieved. Close reading of the articles by three coresearchers yielded an analysis of the emerging concept of translational research. Using the iterative process described by Walker and Avant, a tentative definition of the concept of translational research, along with antecedents and consequences were identified. Implications for health care professionals in education, practice, and research are offered. Further research is needed to determine the adequacy of the definition, to identify empirical referents, and to guide theory development. The study resulted in a theoretical definition of the concept of translational research, along with identification of antecedents and consequences and a description of an ideal or model case to illustrate the definition. Implications for practice and education include the importance of focusing on translational research approaches that may reduce the research-practice gap in health care, thereby improving patient care delivery. Research is needed to determine the usefulness of the definition in health care clinical practice.

Bowel preparation for CT colonography

International Nuclear Information System (INIS)

Neri, Emanuele; Lefere, Philippe; Gryspeerdt, Stefaan; Bemi, Pietro; Mantarro, Annalisa; Bartolozzi, Carlo

2013-01-01

Bowel preparation represents an essential part of CT colonography, as the accuracy of the exam is strongly related to the adequacy of colonic cleansing, and a poor bowel preparation may compromise the diagnostic quality even despite optimization of all other acquisition parameters. Residual stool and fluid in the large bowel may affect the interpretation of the exam and may increase the number of false positives and false negatives. In this regard, the majority of patients having undergone CT colonography state that bowel preparation is the most unpleasant part. Unfortunately, to date no definite consensus has been reached about the ideal bowel preparation technique, and there is great variability in preparation strategies across diagnostic centers. The purpose of this review article is to describe the development and evolution of bowel preparation techniques in order to choose the best approach for optimizing the diagnostic quality of CT colonography in each patient

Bowel preparation for CT colonography

Energy Technology Data Exchange (ETDEWEB)

Neri, Emanuele, E-mail: emanuele.neri@med.unipi.it [Diagnostic and Interventional Radiology, University of Pisa (Italy); Lefere, Philippe; Gryspeerdt, Stefaan [Department of Radiology, Stedelijk Ziekenhuis, Roeselare (Belgium); Bemi, Pietro; Mantarro, Annalisa; Bartolozzi, Carlo [Diagnostic and Interventional Radiology, University of Pisa (Italy)

2013-08-15

Bowel preparation represents an essential part of CT colonography, as the accuracy of the exam is strongly related to the adequacy of colonic cleansing, and a poor bowel preparation may compromise the diagnostic quality even despite optimization of all other acquisition parameters. Residual stool and fluid in the large bowel may affect the interpretation of the exam and may increase the number of false positives and false negatives. In this regard, the majority of patients having undergone CT colonography state that bowel preparation is the most unpleasant part. Unfortunately, to date no definite consensus has been reached about the ideal bowel preparation technique, and there is great variability in preparation strategies across diagnostic centers. The purpose of this review article is to describe the development and evolution of bowel preparation techniques in order to choose the best approach for optimizing the diagnostic quality of CT colonography in each patient.

Reproducibility of CT bone dosimetry: Operator versus automated ROI definition

International Nuclear Information System (INIS)

Louis, O.; Luypaert, R.; Osteaux, M.; Kalender, W.

1988-01-01

Intrasubject reproducibility with repeated determination of vertebral mineral density from a given set of CT images was investigated. The region of interest (ROI) in 10 patient scans was selected by four independent operators either manually or with an automated procedure separating cortical and spongeous bone, the operators being requested to interact in ROI selection. The mean intrasubject variation was found to be much lower with the automated process (0.3 to 0.6%) than with the conventional method (2.5 to 5.2%). In a second study, 10 patients were examined twice to determine the reproducibility of CT slice selection by the operator. The errors were of the same order of magnitude as in ROI selection. (orig.)

Satellite Power Systems (SPS) concept definition study (Exhibit D). Volume 5: Systems engineering/integration research and technology

Science.gov (United States)

Hanley, G. M.

1981-01-01

Guidelines and ground rules followed in the development of requirements for the SPS are presented. Development planning objectives are specified in each of these areas, and evolutionary SPS program scenarios are described for the various concepts studied during the past one year contract. Program descriptions are presented as planning packages of technical tasks, and schedule phasing. Each package identifies the ground based technology effort that will facilitate SPS definitions, designs, development, and operations.

Life is hard: countering definitional pessimism concerning the definition of life

Science.gov (United States)

Smith, Kelly C.

2016-10-01

Cleland and Chyba published a classic piece in 2002 that began a movement I call definitional pessimism, where it is argued that there is no point in attempting anything like a general definition of life. This paper offers a critical response to the pessimist position in general and the influential arguments offered by Cleland and her collaborators in particular. One such argument is that all definitions of life fall short of an ideal in which necessary and sufficient conditions produce unambiguous categorizations that dispose of all counterexamples. But this concept of definition is controversial within philosophy; a fact that greatly diminishes the force of the admonition that biologists should conform to such an ideal. Moreover, biology may well be fundamentally different from logic and the physical sciences from which this ideal is drawn, to the point where definitional conformity misrepresents biological reality. Another idea often pushed is that the prospects for definitional success concerning life are on a par with medieval alchemy's attempts to define matter - that is, doomed to fail for lack of a unifying scientific theory. But this comparison to alchemy is both historically inaccurate and unfair. Planetary science before the discovery of the first exoplanets offers a much better analogy, with much more optimistic conclusions. The pessimists also make much of the desirability of using microbes as models for any universal concept of life, from which they conclude that certain types of 'Darwinian' evolutionary definitions are inadequate. But this argument posits an unrealistic ideal, as no account of life can both be universal and do justice to the sorts of precise causal mechanisms microbes exemplify. The character of biology and the demand for universality in definitions of life thus probably accords better with functional rather than structural categories. The bottom line is that there is simply no viable alternative, either pragmatically or

A Bayesian concept learning approach to crowdsourcing

DEFF Research Database (Denmark)

Viappiani, P.; Zilles, S.; Hamilton, H.J.

2011-01-01

techniques, inference methods, and query selection strategies to assist a user charged with choosing a configuration that satisfies some (partially known) concept. Our model is able to simultaneously learn the concept definition and the types of the experts. We evaluate our model with simulations, showing......We develop a Bayesian approach to concept learning for crowdsourcing applications. A probabilistic belief over possible concept definitions is maintained and updated according to (noisy) observations from experts, whose behaviors are modeled using discrete types. We propose recommendation...

Hidden Curriculum: An Analytical Definition

Directory of Open Access Journals (Sweden)

Mohammad Reza Andarvazh

2018-03-01

Full Text Available Background: The concept of hidden curriculum was first used by Philip Jackson in 1968, and Hafferty brought this concept to the medical education. Many of the subjects that medical students learn are attributed to this curriculum. So far several definitions have been presented for the hidden curriculum, which on the one hand made this concept richer, and on the other hand, led to confusion and ambiguity.This paper tries to provide a clear and comprehensive definition of it.Methods: In this study, concept analysis of McKenna method was used. Using keywords and searching in the databases, 561 English and 26 Persian references related to the concept was found, then by limitingthe research scope, 125 abstracts and by finding more relevant references, 55 articles were fully studied.Results: After analyzing the definitions by McKenna method, the hidden curriculum is defined as follows: The hidden curriculum is a hidden, powerful, intrinsic in organizational structure and culture and sometimes contradictory message, conveyed implicitly and tacitly in the learning environment by structural and human factors and its contents includes cultural habits and customs, norms, values, belief systems, attitudes, skills, desires and behavioral and social expectations can have a positive or negative effect, unplanned, neither planners nor teachers, nor learners are aware of it. The ultimate consequence of the hidden curriculum includes reproducing the existing class structure, socialization, and familiarizing learners for transmission and joining the professional world.Conclusion: Based on the concept analysis, we arrived at an analytical definition of the hidden curriculum that could be useful for further studies in this area.Keywords: CONCEPT ANALYSIS, HIDDEN CURRICULUM, MCKENNA’S METHOD

Helical CT in acute lower gastrointestinal bleeding

International Nuclear Information System (INIS)

Ernst, Olivier; Leroy, Christophe; Sergent, Geraldine; Bulois, Philippe; Saint-Drenant, Sophie; Paris, Jean-Claude

2003-01-01

The purpose of this study was to assess the usefulness of helical CT in depicting the location of acute lower gastrointestinal bleeding. A three-phase helical CT of the abdomen was performed in 24 patients referred for acute lower gastrointestinal bleeding. The diagnosis of the bleeding site was established by CT when there was at least one of the following criteria: spontaneous hyperdensity of the peribowel fat; contrast enhancement of the bowel wall; vascular extravasation of the contrast medium; thickening of the bowel wall; polyp or tumor; or vascular dilation. Diverticula alone were not enough to locate the bleeding site. The results of CT were compared with the diagnosis obtained by colonoscopy, enteroscopy, or surgery. A definite diagnosis was made in 19 patients. The bleeding site was located in the small bowel in 5 patients and the colon in 14 patients. The CT correctly located 4 small bowel hemorrhages and 11 colonic hemorrhages. Diagnosis of the primary lesion responsible for the bleeding was made in 10 patients. Our results suggest that helical CT could be a good diagnostic tool in acute lower gastrointestinal bleeding to help the physician to diagnose the bleeding site. (orig.)

Dual tracer functional imaging of gastroenteropancreatic neuroendocrine tumors using 68Ga-DOTA-NOC PET-CT and 18F-FDG PET-CT: competitive or complimentary?

Science.gov (United States)

Naswa, Niraj; Sharma, Punit; Gupta, Santosh Kumar; Karunanithi, Sellam; Reddy, Rama Mohan; Patnecha, Manish; Lata, Sneh; Kumar, Rakesh; Malhotra, Arun; Bal, Chandrasekhar

2014-01-01

This study aimed to compare the diagnostic performance of Ga-DOTANOC PET/CT with F-FDG PET/CT in the patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Data of 51 patients with definite histological diagnosis of GEP-NET who underwent both Ga-DOTA-NOC PET-CT and F-FDG PET-CT within a span of 15 days were selected for this retrospective analysis. Sensitivity, specificity, and predictive values were calculated for Ga-DOTA-NOC PET-CT and F-FDG PET-CT, and results were compared both on patientwise and regionwise analysis. Ga-DOTA-NOC PET-CT is superior to F-FDG PET-CT on patientwise analysis (P DOTA-NOC PET-CT is superior to F-FDG PET-CT only for lymph node metastases (P DOTA-NOC PET-CT detected more liver and skeletal lesions compared with F-FDG PET-CT, the difference was not statistically significant. In addition, the results of combined imaging helped in selecting candidates who would undergo the appropriate mode of treatment, whether octreotide therapy or conventional chemotherapy Ga-DOTA-NOC PET-CT seems to be superior to F-FDG PET-CT for imaging GEP-NETs. However, their role seems to be complementary because combination of Ga-DOTA-NOC PET-CT and F-FDG PET-CT in such patients helps demonstrate the total disease burden and segregate them to proper therapeutic groups.

Image-Based Treatment Planning of the Post-Lumpectomy Breast Utilizing CT and 3TMRI

International Nuclear Information System (INIS)

Jacobson, G.; Betts, V.; Muruganandham, M.; Buechler-Price, J.; Zamba, G.

2011-01-01

Accurate lumpectomy cavity definition is critical in breast treatment planning. We compared contouring lumpectomy cavity volume and cavity visualization score (CVS) with CT versus 3T MRI. 29 patients were imaged with CT and 3T MRI. Seven additional boost planning sets were obtained for 36 image sets total. Three observers contoured the lumpectomy cavity on all images, assigning a cavity visualization score (CVS ) of 1 to 5. Measures of consistency and agreement for CT volumes were 98.84% and 98.62%, for T1 MRI were 95.65% and 95.55%, and for T2 MRI were 97.63% and 97.71%. The mean CT, T1 MRI, and T2 MRI CVS scores were 3.28, 3.38, and 4.32, respectively. There was a highly significant difference between CT and T2 scores (P<.00001) and between T1 and T2 scores (P<.00001). Interobserver consistency and agreement regarding volumes were high for all three modalities with T2 MRI CVS the highest. MRI may contribute to target definition in selected patients

Image-Based Treatment Planning of the Post-Lumpectomy Breast Utilizing CT and 3TMRI

Directory of Open Access Journals (Sweden)

Geraldine Jacobson

2011-01-01

Full Text Available Accurate lumpectomy cavity definition is critical in breast treatment planning. We compared contouring lumpectomy cavity volume and cavity visualization score (CVS with CT versus 3T MRI. 29 patients were imaged with CT and 3T MRI. Seven additional boost planning sets were obtained for 36 image sets total. Three observers contoured the lumpectomy cavity on all images, assigning a cavity visualization score (CVS of 1 to 5. Measures of consistency and agreement for CT volumes were 98.84% and 98.62%, for T1 MRI were 95.65% and 95.55%, and for T2 MRI were 97.63% and 97.71%. The mean CT, T1 MRI, and T2 MRI CVS scores were 3.28, 3.38, and 4.32, respectively. There was a highly significant difference between CT and T2 scores (<.00001 and between T1 and T2 scores (<.00001. Interobserver consistency and agreement regarding volumes were high for all three modalities with T2 MRI CVS the highest. MRI may contribute to target definition in selected patients.

Respiratory Motion Management in PET/CT: Applications and Clinical Usefulness.

Science.gov (United States)

Guerra, Luca; Ponti, Elena De; Morzenti, Sabrina; Spadavecchia, Chiara; Crivellaro, Cinzia

2017-01-01

Breathing movement can introduce heavy bias in both image quality and quantitation in PET/CT. The aim of this paper is a review of the literature to evaluate the benefit of respiratory gating in terms of image quality, quantification and lesion detectability. A review of the literature published in the last 10 years and dealing with gated PET/CT technique has been performed, focusing on improvement in quantification, lesion detectability and diagnostic accuracy in neoplastic lesion. In addition, the improvement in the definition of radiotherapy planning has been evaluated. There is a consistent increase of the Standardized Uptake Value (SUV) in gated PET images when compared to ungated ones, particularly for lesions located in liver and in lung. Respiratory gating can also increase sensitivity, specificity and accuracy of PET/CT. Gated PET/CT can be used for radiation therapy planning, reducing the uncertainty in target definition, optimizing the volume to be treated and reducing the possibility of "missing" during the dose delivery. Moreover, new technologies, able to define the movement of lesions and organs directly from the PET sinogram, can solve some problems that currently are limiting the clinical use of gated PET/CT (i.e.: extended acquisition time, radiation exposure). The published literature demonstrated that respiratory gating PET/CT is a valid technique to improve quantification, lesion detectability of lung and liver tumors and can better define the radiotherapy planning of moving lesions and organs. If new technical improvements for motion compensation will be clinically validated, gated technique could be applied routinely in any PET/CT scan. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Concept Evaluation Using the PDSA Cycle for Continuous Quality Improvement.

Science.gov (United States)

Laverentz, Delois Meyer; Kumm, Sharon

As concept-based nursing education gains popularity, there is little literature on how to sustain quality after initiation of the curriculum. Critical appraisal of concepts in a university program revealed varying definitions, attributes, and exemplars resulting in student confusion. The Plan, Do, Study, Act (PDSA) cycle for continuous quality improvement was used for concept evaluation. The goals of the evaluation project were: 1) to develop common definition and attributes for concepts and 2) to develop horizontal and vertical leveling of exemplars to build on prior student learning. The continuous quality improvement process can be used to prevent "concept creep" and ensure internal consistency of concept definitions, attributes, and exemplars.

Participation and social participation: are they distinct concepts?

Science.gov (United States)

Piškur, Barbara; Daniëls, Ramon; Jongmans, Marian J; Ketelaar, Marjolijn; Smeets, Rob J E M; Norton, Meghan; Beurskens, Anna J H M

2014-03-01

The concept of participation has been extensively used in health and social care literature since the World Health Organization introduced its description in the International Classification of Functioning, Disability and Health (ICF) in 2001. More recently, the concept of social participation is frequently used in research articles and policy reports. However, in the ICF, no specific definition exists for social participation, and an explanation of differences between the concepts is not available. The central question in this discussion article is whether participation, as defined by the ICF, and social participation are distinct concepts. This article illustrates the concepts of participation and social participation, presents a critical discussion of their definitions, followed by implications for rehabilitation and possible future directions. A clear definition for participation or social participation does not yet exist. Definitions for social participation differ from each other and are not sufficiently distinct from the ICF definition of participation. Although the ICF is regarded an important conceptual framework, it is criticised for not being comprehensive. The relevance of societal involvement of clients is evident for rehabilitation, but the current ICF definition of participation does not sufficiently capture societal involvement. Changing the ICF's definition of participation towards social roles would overcome a number of its shortcomings. Societal involvement would then be understood in the light of social roles. Consequently, there would be no need to make a distinction between social participation and participation.

Estimating cancer risks induced by CT screening for Korea population

International Nuclear Information System (INIS)

Yang, Hye Jeong; Yang, Won Seok

2016-01-01

Computed Tomography(CT) has been used to diagnose early stages of cancer and other diseases. Since the number of CT screening has been increasing, there is now a debate about the possible benefits and risks of CT screening on asymptomatic individuals. CT screening has definite benefits, however the radiation risk of screening an asymptomatic individual is a serious problem that cannot be overlooked. Despite its potential risks, CT screening for asymptomatic individual has been gradually increased in Korea and it is attributed to increase collective effective dose. Therefore, we reported the risk level of each organ which is included in scan field for CT screening and analyzed and then evaluated the risk level of Korean population comparison to others, Hong Kong, U.S. and U.K. populations. LARs are lower with older ages for all populations of both sexes. We recommend CT screening after the age of 40 because from that age, LAR decreases and the danger of top 5 cancer increases.

Development of a guideline on reading CT images of malignant pleural mesothelioma and selection of the reference CT films

International Nuclear Information System (INIS)

Zhou, Huashi; Tamura, Taro; Kusaka, Yukinori; Suganuma, Narufumi; Subhannachart, Ponglada; Vijitsanguan, Chomphunut; Noisiri, Weeraya; Hering, Kurt G.; Akira, Masanori; Itoh, Harumi

2012-01-01

Purpose: International experts developed a guideline on reading CT images of malignant pleural mesothelioma for radiologists and physicians. It is intended that it act as a supplement to the current International Classification of HRCT for Occupational and Environmental Respiratory Diseases. Methods: The research literatures on mesothelioma CT features were systematically reviewed. Ten mesothelioma CT features were adopted into the guideline prepared according to experts’ opinion. The terminology of mesothelioma CT features and mesothelioma probability were agreed by consensus of experts. The CT reference films for each mesothelioma feature were selected based on agreement by experts from 22 definite mesothelioma cases confirmed pathologically and immunohistochemically. To support the validity of the mesothelioma probability, 4 experts’ readings of CT films from 57 cases with or without mesothelioma were analyzed by kappa statistics between the experts; sensitivity and specificity for mesothelioma were also assessed. Results: The mesothelioma CT Guideline was developed, providing the terminology of CT features and the mesothelioma probability, the judgement of severity, the distribution of mesothelioma, and the revised CT reading sheet including mesothelioma items. The CT reference films with ten mesothelioma typical features were selected. The average linearly and quadratically weighted kappa of the agreement on the 4-point scale mesothelioma probability were 0.58 and 0.71, respectively. The average sensitivity and specificity for mesothelioma were 93.2% and 65.6%, respectively. Conclusion: The evidence-based mesothelioma CT Guideline developed may serve as a good educational tool to facilitate physicians in recognising mesothelioma and improve their proficiency in diagnosis of mesothelioma.

Development of a guideline on reading CT images of malignant pleural mesothelioma and selection of the reference CT films

Energy Technology Data Exchange (ETDEWEB)

Zhou, Huashi, E-mail: zhouhua@u-fukui.ac.jp [Department of Environmental Health, School of Medicine, University of Fukui, 23-3 Shimoaitsuki, Matsuoka, Eihezi-cho, Fukui Prefecture 910-1193 (Japan); Tamura, Taro, E-mail: tarou@u-fukui.ac.jp [Department of Environmental Health, School of Medicine, University of Fukui, 23-3 Shimoaitsuki, Matsuoka, Eihezi-cho, Fukui Prefecture 910-1193 (Japan); Kusaka, Yukinori, E-mail: kusakayk@gmail.com [Department of Environmental Health, School of Medicine, University of Fukui, 23-3 Shimoaitsuki, Matsuoka, Eihezi-cho, Fukui Prefecture 910-1193 (Japan); Suganuma, Narufumi, E-mail: nsuganuma@kochi-u.ac.jp [Department of Environmental Medicine, Kochi University School of Medicine (Japan); Subhannachart, Ponglada, E-mail: pongladas@gmail.com [Central Chest Disease Institute of Thailand, 39 Moo 9, Tiwanon Road, Muang Nonthaburi 11000 (Thailand); Vijitsanguan, Chomphunut, E-mail: Chompoo_vj@yahoo.com [Central Chest Disease Institute of Thailand, 39 Moo 9, Tiwanon Road, Muang Nonthaburi 11000 (Thailand); Noisiri, Weeraya, E-mail: weeraya_tat@yahoo.com [Central Chest Disease Institute of Thailand, 39 Moo 9, Tiwanon Road, Muang Nonthaburi 11000 (Thailand); Hering, Kurt G., E-mail: k.g.hering@t-online.de [Department of Diagnostic Radiology, Radiooncology and Nuclear Medicine, Radiological Clinic, Miner' s Hospital, Radiologische Klinik, Lansppaschaftskranhaus Dortmund, Wieckesweg 27 44309, Dortmund (Germany); Akira, Masanori, E-mail: akira@kch.hosp.go.jp [Department of Radiology, National Hospital Organization Kinki-Chuo Chest Medical Center, 1180 Nagasone-cho, Kita-ku, Sakai, Osaka 591-8555 (Japan); Itoh, Harumi, E-mail: hitoh@fmsrsa.fukui-med.ac.jp [Department of Environmental Health, School of Medicine, University of Fukui, 23-3 Shimoaitsuki, Matsuoka, Eihezi-cho, Fukui Prefecture 910-1193 (Japan); Department of Radiology, School of Medicine, University of Fukui, 23-3 Shimoaitsuki Matsuoka, Eiheizi-cho, Fukui Prefecture 910-1193 (Japan); and others

2012-12-15

Purpose: International experts developed a guideline on reading CT images of malignant pleural mesothelioma for radiologists and physicians. It is intended that it act as a supplement to the current International Classification of HRCT for Occupational and Environmental Respiratory Diseases. Methods: The research literatures on mesothelioma CT features were systematically reviewed. Ten mesothelioma CT features were adopted into the guideline prepared according to experts’ opinion. The terminology of mesothelioma CT features and mesothelioma probability were agreed by consensus of experts. The CT reference films for each mesothelioma feature were selected based on agreement by experts from 22 definite mesothelioma cases confirmed pathologically and immunohistochemically. To support the validity of the mesothelioma probability, 4 experts’ readings of CT films from 57 cases with or without mesothelioma were analyzed by kappa statistics between the experts; sensitivity and specificity for mesothelioma were also assessed. Results: The mesothelioma CT Guideline was developed, providing the terminology of CT features and the mesothelioma probability, the judgement of severity, the distribution of mesothelioma, and the revised CT reading sheet including mesothelioma items. The CT reference films with ten mesothelioma typical features were selected. The average linearly and quadratically weighted kappa of the agreement on the 4-point scale mesothelioma probability were 0.58 and 0.71, respectively. The average sensitivity and specificity for mesothelioma were 93.2% and 65.6%, respectively. Conclusion: The evidence-based mesothelioma CT Guideline developed may serve as a good educational tool to facilitate physicians in recognising mesothelioma and improve their proficiency in diagnosis of mesothelioma.

What is the complementary role of ultrasound evaluation in the diagnosis of acute appendicitis after CT?

Energy Technology Data Exchange (ETDEWEB)

Jang, Kyung Mi [Department of Radiology, Hallym University Sacred Heart Hospital, Anyang (Korea, Republic of); Lee, Kwanseop [Department of Radiology, Hallym University Sacred Heart Hospital, Anyang (Korea, Republic of)], E-mail: kwanseop@hallym.or.kr; Kim, Min-Jeong; Yoon, Hoi Soo; Jeon, Eui Yong; Koh, Sung Hye [Department of Radiology, Hallym University Sacred Heart Hospital, Anyang (Korea, Republic of); Min, Kwangseon [Department of Pathology, Hallym University Sacred Heart Hospital, Anyang (Korea, Republic of); Choi, Dongil [Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (Korea, Republic of)

2010-04-15

The objective of our study was to estimate the complementary role of ultrasound evaluation in the diagnosis of acute appendicitis after abdominoplevic CT. A total of 104 patients initially underwent abdominopelvic CT before appendix US due to acute abdominal pain. All CT examinations were evaluated retrospectively for the presence of acute appendicitis. The findings of appendix on CT were classified into five categories (definite appendicitis, probably appendicitis, equivocal CT findings for diagnosis of appendicitis, probably not appendicitis, and normal looking appendix). Appendix US images and their radiologic reports were also evaluated retrospectively. Then, CT and US findings were correlated with clinical or pathologic diagnosis. Three all patients with definite appendicitis initially on CT again showed US findings of appendicitis. In the 32 patients of probably appendicitis on CT, US showed normal looking appendix in seven patients (21.8%, 7 of 32) who improved with medical treatment and discharged. In the 16 patients of equivocal CT findings for diagnosis of appendicitis, US showed appendicitis in seven patients (43.8%, 7 of 16) and normal looking appendix in nine patients. In the 12 patients of probably not appendicitis on CT, US showed acute appendicitis in two patients (16.7%, 2 of 12). In the 41 patients of normal looking appendix on CT, US showed acute appendicitis in five patients (12.2%, 5 of 41). US reevaluation enables us to avoid misdiagnosis of appendicitis on CT and improve diagnostic accuracy of acute appendicitis.

Concepts of scale

NARCIS (Netherlands)

Padt, F.J.G.; Arts, B.J.M.

2014-01-01

This chapter provides some clarity to the scale debate. It bridges a variety of approaches, definitions and jargons used in various disciplines in order to provide common ground for a concept of scale as a basis for scale-sensitive governance of the environment. The chapter introduces the concept of

Co-registration of pre-operative CT with ex vivo surgically excised ground glass nodules to define spatial extent of invasive adenocarcinoma on in vivo imaging: a proof-of-concept study

Energy Technology Data Exchange (ETDEWEB)

Rusu, Mirabela [Case Western Reserve University, Department of Biomedical Engineering, Cleveland, OH (United States); GE Global Research, Niskayuna, NY (United States); Rajiah, Prabhakar [UT Southwestern Medical Center, Dallas, TX (United States); Cleveland Medical Center and Case Western Reserve University, University Hospitals, Cleveland, OH (United States); Gilkeson, Robert; Yang, Michael; Donatelli, Christopher; Linden, Philip [Cleveland Medical Center and Case Western Reserve University, University Hospitals, Cleveland, OH (United States); Thawani, Rajat; Madabhushi, Anant [Case Western Reserve University, Department of Biomedical Engineering, Cleveland, OH (United States); Jacono, Frank J. [Cleveland Medical Center and Case Western Reserve University, University Hospitals, Cleveland, OH (United States); Louis Stokes Cleveland VA Medical Center, Cleveland, OH (United States)

2017-10-15

To develop an approach for radiology-pathology fusion of ex vivo histology of surgically excised pulmonary nodules with pre-operative CT, to radiologically map spatial extent of the invasive adenocarcinomatous component of the nodule. Six subjects (age: 75 ± 11 years) with pre-operative CT and surgically excised ground-glass nodules (size: 22.5 ± 5.1 mm) with a significant invasive adenocarcinomatous component (>5 mm) were included. The pathologist outlined disease extent on digitized histology specimens; two radiologists and a pulmonary critical care physician delineated the entire nodule on CT (in-plane resolution: <0.8 mm, inter-slice distance: 1-5 mm). We introduced a novel reconstruction approach to localize histology slices in 3D relative to each other while using CT scan as spatial constraint. This enabled the spatial mapping of the extent of tumour invasion from histology onto CT. Good overlap of the 3D reconstructed histology and the nodule outlined on CT was observed (65.9 ± 5.2%). Reduction in 3D misalignment of corresponding anatomical landmarks on histology and CT was observed (1.97 ± 0.42 mm). Moreover, the CT attenuation (HU) distributions were different when comparing invasive and in situ regions. This proof-of-concept study suggests that our fusion method can enable the spatial mapping of the invasive adenocarcinomatous component from 2D histology slices onto in vivo CT. (orig.)

Co-registration of pre-operative CT with ex vivo surgically excised ground glass nodules to define spatial extent of invasive adenocarcinoma on in vivo imaging: a proof-of-concept study

International Nuclear Information System (INIS)

Rusu, Mirabela; Rajiah, Prabhakar; Gilkeson, Robert; Yang, Michael; Donatelli, Christopher; Linden, Philip; Thawani, Rajat; Madabhushi, Anant; Jacono, Frank J.

2017-01-01

To develop an approach for radiology-pathology fusion of ex vivo histology of surgically excised pulmonary nodules with pre-operative CT, to radiologically map spatial extent of the invasive adenocarcinomatous component of the nodule. Six subjects (age: 75 ± 11 years) with pre-operative CT and surgically excised ground-glass nodules (size: 22.5 ± 5.1 mm) with a significant invasive adenocarcinomatous component (>5 mm) were included. The pathologist outlined disease extent on digitized histology specimens; two radiologists and a pulmonary critical care physician delineated the entire nodule on CT (in-plane resolution: <0.8 mm, inter-slice distance: 1-5 mm). We introduced a novel reconstruction approach to localize histology slices in 3D relative to each other while using CT scan as spatial constraint. This enabled the spatial mapping of the extent of tumour invasion from histology onto CT. Good overlap of the 3D reconstructed histology and the nodule outlined on CT was observed (65.9 ± 5.2%). Reduction in 3D misalignment of corresponding anatomical landmarks on histology and CT was observed (1.97 ± 0.42 mm). Moreover, the CT attenuation (HU) distributions were different when comparing invasive and in situ regions. This proof-of-concept study suggests that our fusion method can enable the spatial mapping of the invasive adenocarcinomatous component from 2D histology slices onto in vivo CT. (orig.)

Decreased occipital lobe metabolism by FDG-PET/CT: An anti-NMDA receptor encephalitis biomarker.

Science.gov (United States)

Probasco, John C; Solnes, Lilja; Nalluri, Abhinav; Cohen, Jesse; Jones, Krystyna M; Zan, Elcin; Javadi, Mehrbod S; Venkatesan, Arun

2018-01-01

To compare brain metabolism patterns on fluorodeoxyglucose (FDG)-PET/CT in anti-NMDA receptor and other definite autoimmune encephalitis (AE) and to assess how these patterns differ between anti-NMDA receptor neurologic disability groups. Retrospective review of clinical data and initial dedicated brain FDG-PET/CT studies for neurology inpatients with definite AE, per published consensus criteria, treated at a single academic medical center over a 10-year period. Z-score maps of FDG-PET/CT were made using 3-dimensional stereotactic surface projections in comparison to age group-matched controls. Brain region mean Z scores with magnitudes ≥2.00 were interpreted as significant. Comparisons were made between anti-NMDA receptor and other definite AE patients as well as among patients with anti-NMDA receptor based on modified Rankin Scale (mRS) scores at the time of FDG-PET/CT. The medial occipital lobes were markedly hypometabolic in 6 of 8 patients with anti-NMDA receptor encephalitis and as a group (Z = -4.02, interquartile range [IQR] 2.14) relative to those with definite AE (Z = -2.32, 1.46; p = 0.004). Among patients with anti-NMDA receptor encephalitis, the lateral and medial occipital lobes were markedly hypometabolic for patients with mRS 4-5 (lateral occipital lobe Z = -3.69, IQR 1; medial occipital lobe Z = -4.08, 1) compared with those with mRS 0-3 (lateral occipital lobe Z = -0.83, 2; p occipital lobe Z = -1.07, 2; p = 0.001). Marked medial occipital lobe hypometabolism by dedicated brain FDG-PET/CT may serve as an early biomarker for discriminating anti-NMDA receptor encephalitis from other AE. Resolution of lateral and medial occipital hypometabolism may correlate with improved neurologic status in anti-NMDA receptor encephalitis.

Auditing Complex Concepts in Overlapping Subsets of SNOMED

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Wang, Yue; Wei, Duo; Xu, Junchuan; Elhanan, Gai; Perl, Yehoshua; Halper, Michael; Chen, Yan; Spackman, Kent A.; Hripcsak, George

2008-01-01

Limited resources and the sheer volume of concepts make auditing a large terminology, such as SNOMED CT, a daunting task. It is essential to devise techniques that can aid an auditor by automatically identifying concepts that deserve attention. A methodology for this purpose based on a previously introduced abstraction network (called the p-area taxonomy) for a SNOMED CT hierarchy is presented. The methodology algorithmically gathers concepts appearing in certain overlapping subsets, defined exclusively with respect to the p-area taxonomy, for review. The results of applying the methodology to SNOMED’s Specimen hierarchy are presented. These results are compared against a control sample composed of concepts residing in subsets without the overlaps. With the use of the double bootstrap, the concept group produced by our methodology is shown to yield a statistically significant higher proportion of error discoveries. PMID:18998838

CT diagnosis of pancreatitis and carcinoma of the pancreas

International Nuclear Information System (INIS)

Sager, W.D.; Nedden, D. zur; Lepuschuetz, H.; Zalaudek, G.; Bodner, E.; Fotter, R.; Lammer, J.; Innsbruck Univ.; Graz Univ.; Innsbruck Univ.

1981-01-01

The article reports on 78 CT scans of surgically diseases of the pancreas, 30 cases of chronic pancreatitis, 12 cases of haemorrhagic-necrotizing pancreatitis, and 36 cases of carcinoma of the pancreas. 12 of these cases were operable, whereas 234 were inoperable. The operable carcinomas were so small that proper diagnosis was effected in 50% only, whereas the inoperable carcinomas eluded CT identification in 17% of the cases only. The most important signs of an operable carcinoma of the pancreas are a well-defined enlargement and inhomogeneity of the parenchyma with reduced contrast, especially on bolus injection, as well as dilatation of the bile duct system. The most essential criteria for inoperability are absence of boundaries, especially towards the dorsal side, with infiltration of the retroperitoneal fatty tissue, and lack of delineation of the large vessels. According to the present state of the art, CT does not supply definite criteria for differentiating between an operable carcinoma of the pancreas and chronic fibrotic pancreatitis. Overstepping of the marginal contours is a reliably distinctive feature between carcinoma and pancreatitis, but it also points to the inoperable nature of the disease. Haemorrhagic-necrotizing pancreatitis is characterized by definite CT criteria, so that diagnosis is easy. Computerised tomography is a valuable diagnostic tool in diseases of the pancreas and can supply conclusive pointers towards the operability of a tumor. (orig.) [de

Enriching a primary health care version of ICD-10 using SNOMED CT mapping

Directory of Open Access Journals (Sweden)

Nyström Mikael

2010-06-01

Full Text Available Abstract Background In order to satisfy different needs, medical terminology systems must have richer structures. This study examines whether a Swedish primary health care version of the mono-hierarchical ICD-10 (KSH97-P may obtain a richer structure using category and chapter mappings from KSH97-P to SNOMED CT and SNOMED CT's structure. Manually-built mappings from KSH97-P's categories and chapters to SNOMED CT's concepts are used as a starting point. Results The mappings are manually evaluated using computer-produced information and a small number of mappings are updated. A new and poly-hierarchical chapter division of KSH97-P's categories has been created using the category and chapter mappings and SNOMED CT's generic structure. In the new chapter division, most categories are included in their original chapters. A considerable number of concepts are included in other chapters than their original chapters. Most of these inclusions can be explained by ICD-10's design. KSH97-P's categories are also extended with attributes using the category mappings and SNOMED CT's defining attribute relationships. About three-fourths of all concepts receive an attribute of type Finding site and about half of all concepts receive an attribute of type Associated morphology. Other types of attributes are less common. Conclusions It is possible to use mappings from KSH97-P to SNOMED CT and SNOMED CT's structure to enrich KSH97-P's mono-hierarchical structure with a poly-hierarchical chapter division and attributes of type Finding site and Associated morphology. The final mappings are available as additional files for this paper.

Concepts of happiness across time and cultures.

Science.gov (United States)

Oishi, Shigehiro; Graham, Jesse; Kesebir, Selin; Galinha, Iolanda Costa

2013-05-01

We explored cultural and historical variations in concepts of happiness. First, we analyzed the definitions of happiness in dictionaries from 30 nations to understand cultural similarities and differences in happiness concepts. Second, we analyzed the definition of happiness in Webster's dictionaries from 1850 to the present day to understand historical changes in American English. Third, we coded the State of the Union addresses given by U.S. presidents from 1790 to 2010. Finally, we investigated the appearance of the phrases happy nation versus happy person in Google's Ngram Viewer from 1800 to 2008. Across cultures and time, happiness was most frequently defined as good luck and favorable external conditions. However, in American English, this definition was replaced by definitions focused on favorable internal feeling states. Our findings highlight the value of a historical perspective in the study of psychological concepts.

Multiplanar reformatted CT applications in the lumbar spine

International Nuclear Information System (INIS)

Ueda, Takafumi; Kojima, Shinsaburo; Araki, Nobuto; Miyauchi, Sumihiko

1986-01-01

Diagnostic value and limitations of multiplanar reformatted CT were evaluated in 55 patients with lumbar diseases. Reformatted images in coronal, sagittal, paraxial, and oblique planes were acquired from the transverse axial images, thereby allowing three-dimensional visualization of lesions in the lumbar spine. Oblique images that were reformmated along the nervous root were useful in visualizing lesions in the root canal, which were not available on either conventional myelography or transverse axial CT. A definitive plane determination is required for reformation of images, taking curvature of the spinal column into account. (Namekawa, K.)

The niche party concept and its measurement

OpenAIRE

Meyer, Thomas M; Miller, Bernhard

2015-01-01

The concept of the niche party has become increasingly popular in analyses of party competition. Yet, existing approaches vary in their definitions and their measurement approaches. We propose using a minimal definition that allows us to compare political parties in terms of their ?nicheness?. We argue that the conceptual core of the niche party concept is based on issue emphasis and that a niche party emphasizes policy areas neglected by its rivals. Based on this definition, we propose a con...

[Concept analysis "Competency-based education"].

Science.gov (United States)

Loosli, Clarence

2016-03-01

Competency-based education (CBE) stands out at global level as the best educational practice. Indeed, CBE is supposed to improve the quality of care provided by newly graduated nurses. Yet, there is a dearth of knowledge in nursing literature regarding CBE concept's definition. CBE is implemented differently in each entity even inside the same discipline in a single country. What accounts for CBE in nursing education ? to clarify CBE concept meaning according to literature review in order to propose a definition. Wilson concept analysis method framed our literature review through two databases: CINHAL and ERIC. following the 11 Wilson techniques analysis, we identified CBE concept as a multidimensional concept clustering three dimensions : learning, teaching and assessment. nurses educators are accountable for providing performants newly graduated professional to the society. Schools should struggle for the visibility and the transparency of means they are using to accomplish their educational activities. This first attempt to understand CBE concept opens a matter of debate concerning further development and clarification of the concept. This first description of CBE concept is a step toward its identification and assessment.

First installation of a dual-room IVR-CT system in the emergency room.

Science.gov (United States)

Wada, Daiki; Nakamori, Yasushi; Kanayama, Shuji; Maruyama, Shuhei; Kawada, Masahiro; Iwamura, Hiromu; Hayakawa, Koichi; Saito, Fukuki; Kuwagata, Yasuyuki

2018-03-05

Computed tomography (CT) embedded in the emergency room has gained importance in the early diagnostic phase of trauma care. In 2011, we implemented a new trauma workflow concept with a sliding CT scanner system with interventional radiology features (IVR-CT) that allows CT examination and emergency therapeutic intervention without relocating the patient, which we call the Hybrid emergency room (Hybrid ER). In the Hybrid ER, all life-saving procedures, CT examination, damage control surgery, and transcatheter arterial embolisation can be performed on the same table. Although the trauma workflow realized in the Hybrid ER may improve mortality in severe trauma, the Hybrid ER can potentially affect the efficacy of other in/outpatient diagnostic workflow because one room is occupied by one severely injured patient undergoing both emergency trauma care and CT scanning for long periods. In July 2017, we implemented a new trauma workflow concept with a dual-room sliding CT scanner system with interventional radiology features (dual-room IVR-CT) to increase patient throughput. When we perform emergency surgery or interventional radiology for a severely injured or ill patient in the Hybrid ER, the sliding CT scanner moves to the adjacent CT suite, and we can perform CT scanning of another in/outpatient. We believe that dual-room IVR-CT can contribute to the improvement of both the survival of severely injured or ill patients and patient throughput.

Evaluation of the efficiency of FDG PET/CT in detection and characterization of skeletal metastases

Directory of Open Access Journals (Sweden)

Ahmed Wafaie

2014-03-01

Conclusion: Fused PET/CT was highly efficient in evaluation of skeletal metastases with superior performance in: detection of early bone marrow infiltration not apparent on CT, resolution of metabolic activity before definite signs of complete healing on CT, detection of missed sclerotic metastases on PET due to their relatively low metabolic activity, detection of intra and extra osseous recurrence and differentiation of benign from malignant bone lesions.

Linking Keystone Species and Functional Groups: A New Operational Definition of the Keystone Species Concept

Directory of Open Access Journals (Sweden)

Robert D. Davic

2003-07-01

Full Text Available The concept of the "keystone species" is redefined to allow for the a priori prediction of these species within ecosystems. A keystone species is held to be a strongly interacting species whose top-down effect on species diversity and competition is large relative to its biomass dominance within a functional group. This operational definition links the community importance of keystone species to a specific ecosystem process, e.g., the regulation of species diversity, within functional groups at lower trophic levels that are structured by competition for a limited resource. The a priori prediction of keystone species has applied value for the conservation of natural areas.

Virtual non-contrast dual-energy CT compared to single-energy CT of the urinary tract: a prospective study

Energy Technology Data Exchange (ETDEWEB)

Lundin, Margareta; Liden, Mats; Geijer, Haakan; Andersson, Torbjoern [Dept. of Radiology, Oerebro Univ. Hospital, Oerebro Univ., Oerebro (Sweden)], E-mail: margareta.lundin@orebroll.se; Magnuson, Anders [Clinical Epidemiology and Biostatistic Unit, Oerebro Univ. Hospital, Oerebro (Sweden); Mohammed, Ahmed Abdulilah [Dept. of Radiology, Linkoeping Univ. Hospital, Linkoeping (Sweden); Persson, Anders [CMIV Center for Medical Image Science and Visualization, Linkoeping (Sweden)

2012-07-15

Background. Dual-energy computed tomography (DECT) has been shown to be useful for subtracting bone or calcium in CT angiography and gives an opportunity to produce a virtual non-contrast-enhanced (VNC) image from a series where contrast agents have been given intravenously. High noise levels and low resolution have previously limited the diagnostic value of the VNC images created with the first generation of DECT. With the recent introduction of a second generation of DECT, there is a possibility of obtaining VNC images with better image quality at hopefully lower radiation dose compared to the previous generation. Purpose. To compare the image quality of the single-energy series to a VNC series obtained with a two generations of DECT scanners. CT of the urinary tract was used as a model. Material and Methods. Thirty patients referred for evaluation of hematuria were examined with an older system (Somatom Definition) and another 30 patients with a new generation (Somatom Definition Flash). One single-energy series was obtained before and one dual-energy series after administration of intravenous contrast media. We created a VNC series from the contrast-enhanced images. Images were assessed concerning image quality with a visual grading scale evaluation of the VNC series with the single-energy series as gold standard. Results. The image quality of the VNC images was rated inferior to the single-energy variant for both scanners, OR 11.5-67.3 for the Definition and OR 2.1-2.8 for the Definition Flash. Visual noise and overall quality were regarded as better with Flash than Definition. Conclusion. Image quality of VNC images obtained with the new generation of DECT is still slightly inferior compared to native images. However, the difference is smaller with the new compared to the older system.

Virtual non-contrast dual-energy CT compared to single-energy CT of the urinary tract: a prospective study.

Science.gov (United States)

Lundin, Margareta; Lidén, Mats; Magnuson, Anders; Mohammed, Ahmed Abdulilah; Geijer, Håkan; Andersson, Torbjörn; Persson, Anders

2012-07-01

Dual-energy computed tomography (DECT) has been shown to be useful for subtracting bone or calcium in CT angiography and gives an opportunity to produce a virtual non-contrast-enhanced (VNC) image from a series where contrast agents have been given intravenously. High noise levels and low resolution have previously limited the diagnostic value of the VNC images created with the first generation of DECT. With the recent introduction of a second generation of DECT, there is a possibility of obtaining VNC images with better image quality at hopefully lower radiation dose compared to the previous generation. To compare the image quality of the single-energy series to a VNC series obtained with a two generations of DECT scanners. CT of the urinary tract was used as a model. Thirty patients referred for evaluation of hematuria were examined with an older system (Somatom Definition) and another 30 patients with a new generation (Somatom Definition Flash). One single-energy series was obtained before and one dual-energy series after administration of intravenous contrast media. We created a VNC series from the contrast-enhanced images. Images were assessed concerning image quality with a visual grading scale evaluation of the VNC series with the single-energy series as gold standard. The image quality of the VNC images was rated inferior to the single-energy variant for both scanners, OR 11.5-67.3 for the Definition and OR 2.1-2.8 for the Definition Flash. Visual noise and overall quality were regarded as better with Flash than Definition. Image quality of VNC images obtained with the new generation of DECT is still slightly inferior compared to native images. However, the difference is smaller with the new compared to the older system.

Virtual non-contrast dual-energy CT compared to single-energy CT of the urinary tract: a prospective study

International Nuclear Information System (INIS)

Lundin, Margareta; Liden, Mats; Geijer, Haakan; Andersson, Torbjoern; Magnuson, Anders; Mohammed, Ahmed Abdulilah; Persson, Anders

2012-01-01

Background. Dual-energy computed tomography (DECT) has been shown to be useful for subtracting bone or calcium in CT angiography and gives an opportunity to produce a virtual non-contrast-enhanced (VNC) image from a series where contrast agents have been given intravenously. High noise levels and low resolution have previously limited the diagnostic value of the VNC images created with the first generation of DECT. With the recent introduction of a second generation of DECT, there is a possibility of obtaining VNC images with better image quality at hopefully lower radiation dose compared to the previous generation. Purpose. To compare the image quality of the single-energy series to a VNC series obtained with a two generations of DECT scanners. CT of the urinary tract was used as a model. Material and Methods. Thirty patients referred for evaluation of hematuria were examined with an older system (Somatom Definition) and another 30 patients with a new generation (Somatom Definition Flash). One single-energy series was obtained before and one dual-energy series after administration of intravenous contrast media. We created a VNC series from the contrast-enhanced images. Images were assessed concerning image quality with a visual grading scale evaluation of the VNC series with the single-energy series as gold standard. Results. The image quality of the VNC images was rated inferior to the single-energy variant for both scanners, OR 11.5-67.3 for the Definition and OR 2.1-2.8 for the Definition Flash. Visual noise and overall quality were regarded as better with Flash than Definition. Conclusion. Image quality of VNC images obtained with the new generation of DECT is still slightly inferior compared to native images. However, the difference is smaller with the new compared to the older system

Clinical value of 18F-fluorodihydroxyphenylalanine positron emission tomography/computed tomography (18F-DOPA PET/CT) for detecting pheochromocytoma

International Nuclear Information System (INIS)

Luster, Markus; Zeich, Katrin; Glatting, Gerhard; Buck, Andreas K.; Solbach, Christoph; Reske, Sven N.; Karges, Wolfram; Pauls, Sandra; Verburg, Frederik A.; Dralle, Henning; Neumaier, Bernd; Mottaghy, Felix M.

2010-01-01

In detecting pheochromocytoma (PHEO), positron emission tomography (PET) with the radiolabelled amine precursor 18 F-fluorodihydroxyphenylalanine ( 18 F-DOPA) offers excellent specificity, while computed tomography (CT) provides high sensitivity and ability to localize lesions; therefore, the combination of these modalities could be advantageous in this setting. The aim of this study was to investigate whether combined 18 F-DOPA PET/CT more accurately detects and localizes PHEO lesions than does each modality alone. 18 F-DOPA PET, CT and 18 F-DOPA PET/CT images of 25 consecutive patients undergoing diagnostic scanning of suspected sporadic or multiple endocrine neoplasia type 2 syndrome-associated PHEO were reviewed retrospectively in randomized sequence. Two blinded observers scored the images regarding the likelihood of PHEO being present and localizable. Results were correlated with subsequent clinical history and, when available, histology. Of the 19 lesions detected by all three modalities, PET identified each as positive for PHEO, but was unable to definitively localize 15 of 19 (79%). CT could definitively localize all 19 lesions, but could not definitively diagnose or exclude PHEO in 18 of 19 (95%) lesions. Furthermore, CT falsely identified as negative for PHEO one lesion which was judged to be positive for this tumor by both PET and PET/CT. Only in PET/CT scans were all 19 lesions accurately characterized and localized. On a per-patient basis, the sensitivity of 18 F-DOPA PET/CT for PHEO was 100% and the specificity 88%, with a 100% positive predictive value and an 88% negative predictive value. 18 F-DOPA PET/CT more accurately diagnoses and localizes adrenal and extra-adrenal masses suspicious for PHEO than do 18 F-DOPA PET or CT alone. (orig.)

RADIOLOGICAL TIPS CT-guided biopsy of suspected malignancy: A ...

African Journals Online (AJOL)

under appropriate medical therapy and the lesion was successfully excised. ... origin.[4] Typically, these sympathetic tumours secrete catecholamines. It should be noted that phaeochromocytomas, arising from the adrenal medulla, are, by definition, ... Radiologically, CT, MRI, metaidbenzylguanidine scan and PET imaging.

Readiness for hospital discharge: A concept analysis.

Science.gov (United States)

Galvin, Eileen Catherine; Wills, Teresa; Coffey, Alice

2017-11-01

To report on an analysis on the concept of 'readiness for hospital discharge'. No uniform operational definition of 'readiness for hospital discharge' exists in the literature; therefore, a concept analysis is required to clarify the concept and identify an up-to-date understanding of readiness for hospital discharge. Clarity of the concept will identify all uses of the concept; provide conceptual clarity, an operational definition and direction for further research. Literature review and concept analysis. A review of literature was conducted in 2016. Databases searched were: Academic Search Complete, CINAHL Plus with Full Text, PsycARTICLES, Psychology and Behavioural Sciences Collection, PsycINFO, Social Sciences Full Text (H.W. Wilson) and SocINDEX with Full Text. No date limits were applied. Identification of the attributes, antecedents and consequences of readiness for hospital discharge led to an operational definition of the concept. The following attributes belonging to 'readiness for hospital discharge' were extracted from the literature: physical stability, adequate support, psychological ability, and adequate information and knowledge. This analysis contributes to the advancement of knowledge in the area of hospital discharge, by proposing an operational definition of readiness for hospital discharge, derived from the literature. A better understanding of the phenomenon will assist healthcare professionals to recognize, measure and implement interventions where necessary, to ensure patients are ready for hospital discharge and assist in the advancement of knowledge for all professionals involved in patient discharge from hospital. © 2017 John Wiley & Sons Ltd.

Suicide Lethality: A Concept Analysis.

Science.gov (United States)

DeBastiani, Summer; De Santis, Joseph P

2018-02-01

Suicide is a significant health problem internationally. Those who complete suicide may have different behaviors and risk factors than those who attempt a non-fatal suicide. The purpose of this article is to analyze the concept of suicide lethality and propose a clear definition of the concept through the identification of antecedents, attributes, and consequences. A literature search for articles published in the English language between 1970 and 2016 was conducted using MEDLINE, the Cochrane Library, Pubmed, Psychlit, Ovid, PsycINFO, and Proquest. The bibliographies of all included studies were also reviewed to identify additional relevant citations. A concept analysis was conducted on the literature findings using six stages of Walker and Avant's method. The concept analysis differentiated between suicide, lethality, suicidal behavior, and suicide lethality. Presence of a suicide plan or a written suicide note was not found to be associated with the majority of completed suicides included in the definition of suicide lethality. There are a few scales that measure the lethality of a suicide attempt, but none that attempt to measure the concept of suicide lethality as described in this analysis. Clarifying the concept of suicide lethality encourages awareness of the possibility of different suicidal behaviors associated with different suicide outcomes and will inform the development of future nursing interventions. A clearer definition of the concept of suicide lethality will guide clinical practice, research, and policy development aimed at suicide prevention.

Scope Definition

DEFF Research Database (Denmark)

Bjørn, Anders; Owsianiak, Mikołaj; Laurent, Alexis

2018-01-01

The scope definition is the second phase of an LCA. It determines what product systems are to be assessed and how this assessment should take place. This chapter teaches how to perform a scope definition. First, important terminology and key concepts of LCA are introduced. Then, the nine items...... making up a scope definition are elaborately explained: (1) Deliverables. (2) Object of assessment, (3) LCI modelling framework and handling of multifunctional processes, (4) System boundaries and completeness requirements, (5) Representativeness of LCI data, (6) Preparing the basis for the impact...... assessment, (7) Special requirements for system comparisons, (8) Critical review needs and (9) Planning reporting of results. The instructions relate both to the performance and reporting of a scope definition and are largely based on ILCD....

Current concepts in F18 FDG PET/CT-based Radiation Therapy planning for Lung Cancer

Directory of Open Access Journals (Sweden)

Percy eLee

2012-07-01

Full Text Available Radiation therapy is an important component of cancer therapy for early stage as well as locally advanced lung cancer. The use of F18 FDG PET/CT has come to the forefront of lung cancer staging and overall treatment decision-making. FDG PET/CT parameters such as standard uptake value and metabolic tumor volume provide important prognostic and predictive information in lung cancer. Importantly, FDG PET/CT for radiation planning has added biological information in defining the gross tumor volume as well as involved nodal disease. For example, accurate target delineation between tumor and atelectasis is facilitated by utilizing PET and CT imaging. Furthermore, there has been meaningful progress in incorporating metabolic information from FDG PET/CT imaging in radiation treatment planning strategies such as radiation dose escalation based on standard uptake value thresholds as well as using respiratory gated PET and CT planning for improved target delineation of moving targets. In addition, PET/CT based follow-up after radiation therapy has provided the possibility of early detection of local as well as distant recurrences after treatment. More research is needed to incorporate other biomarkers such as proliferative and hypoxia biomarkers in PET as well as integrating metabolic information in adaptive, patient-centered, tailored radiation therapy.

SU-F-J-223: Patterns of Failure for Laryngeal Cancer Patients Treated with Definitive IMRT: Comparing Two Different Methods for Determining the Origin of Recurrence From Follow-Up PET/CT Scans

Energy Technology Data Exchange (ETDEWEB)

Brodin, P; Guha, C; Tome, W [Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York (United States); Kabarriti, R; Kalnicki, S; Garg, M [Montefiore Medical Center, Bronx, New York (United States); Vogelius, I [Rigshospitalet, Copenhagen University Hospital, Copenhagen (Denmark)

2016-06-15

Purpose: To determine patterns of failure in laryngeal cancer treated with definitive IMRT by comparing two different methods for identifying the recurrence epicenter on follow-up PET/CT. Methods: We identified 20 patients treated for laryngeal squamous cell carcinoma with definitive IMRT who had loco-regional recurrence diagnosed on PET/CT. Recurrence PET/CT scans were co-registered with the original treatment planning CT using deformable image registration with the VoxAlign deformation engine in MIM Software. Recurrence volumes were delineated on co-registered follow-up scans using a semi-automatic PETedge tool and two separate methods were used to identify the recurrence point of origin: a) Finding the point within the recurrence volume for which the maximum distance to the surface of the surrounding recurrence volume is smaller than for any other point. b) Finding the point within the recurrence volume with the maximum standardized uptake value (SUVmax), without geometric restrictions.For each method the failure pattern was determined as whether the recurrence origin fell within the original high-dose target volumes GTV70, CTV70, PTV70 (receiving 70Gy), intermediate-risk PTV59 (receiving 59.4Gy) or low-risk PTV54 (receiving 54.1Gy), in the original treatment planning CT. Results: 23 primary/nodal recurrences from the 20 patients were analyzed. The three-dimensional distance between the two different origins was on average 10.5mm (std.dev. 10mm). Most recurrences originated in the high-dose target volumes for both methods with 13 (57%) and 11 (48%) in the GTV70 and 20 (87%) and 20 (87%) in the PTV70 for method a) and b), respectively. There was good agreement between the two methods in classifying the origin target volumes with 69% concordance for GTV70, 89% for CTV70 and 100% for PTV70. Conclusion: With strong agreement in patterns of failure between two separate methods for determining recurrence origin, we conclude that most recurrences occurred within the

Efficacy of FDG PET/CT Imaging for Venous Thromboembolic Disorders

DEFF Research Database (Denmark)

Hess, Søren; Madsen, Poul Henning; Iversen, Else Dalsgaard

2015-01-01

PURPOSE: In recent years, several case reports have described venous thromboembolism (VTE) on FDG PET/CT. In this short communication, we present results from a proof-of-concept pilot study aimed at providing some preliminary data on the efficacy of FDG PET/CT in prospective patients with suspected...

Reference dosimetry for CT in the UK

International Nuclear Information System (INIS)

Shrimpton, P.C.; Wall, B.F.

2001-01-01

Computed tomography is firmly established as a major source of population exposure from diagnostic x-ray examinations and thus a particular focus for radiological protection initiatives. The concept of reference doses is widely recognised as a useful and practical tool for promoting improvements in the optimisation of protection for patients undergoing radiological examinations. National diagnostic reference levels (DRLs) have already been successfully applied in the UK for some conventional x-ray examinations within a framework for advice on patient protection. This approach is being extended to include CT, utilising the robust methodology for reference dosimetry that has been developed by the European Commission (EC) for the particular conditions of exposure in CT. This is based on the dosimetric concepts of weighted computed tomography dose index (CTDI w ) per slice in serial scanning or per rotation in helical scanning, and dose-length product (DLP) per complete examination. Notwithstanding some initial values proposed by the EC, specific national DRLs for CT practice in the UK will be established on the basis of widescale national survey data. (author)

Clinical values of CT and dynamic CT in brain infarction

International Nuclear Information System (INIS)

Lim, Soo Il; Jang, Do; Seo, Eun Joo; Sohn, Myung Hee; Choi, Ki Chul

1985-01-01

With the advent of faster scan time and new computer program, a scanning technique called 'dynamic computed tomography' has become possible. Dynamic computed tomography consisted of performing multiple rapid sequence scans after injection of contrast material. The authors have evaluated the clinical usefulness of computed tomography and dynamic computed tomography of 93 patients with brain infarction and/or ischemia during the period of 17 months from April 1983 to August 1984 in Department of Radiology, Chonbuk National University Hospital. The results were as follows; 1. The age distribution ranged from 18 years to 78 years. Among them the most common age group was between 50 years and 59 years (40.9%). 2. The sites of brain infarction were cerebral lobes (63 cases,68), basal ganglia (15 cases, 16.1%) and multiple sites (6 cases, 6.4%). The common affected site was middle cerebral artery territories. 3. The contrast enhancement of acute infarction was noted in 14 cases (17.5%) which occurred commonly between 3 days and 2 weeks from ictus. 4. The patterns of time-density curve in brain infarction and/or ischemia were as follow: a. Depression of slow wash-in phase was 20 cases (59%). b. Lower peak concentration was 17 cases (50%). c. Lower and delayed peak concentration was 7 cases (21%). d. No definite peak concentration was 6 cases (18%). First three patterns of time-density curve were thought as relatively characteristic curve of brain infarction and/or ischemia. 5. Two cases that showed negative findings on precontrast CT scan appeared to be positive findings as hypodensity on postcontrast CT scan and were confirmed as brain infarction by dynamic CT. 6. The diagnostic entity of dynamic CT scan were as follows; a. large artery thrombotic infarction were 23 cases (58%). b. lacnar infarction were 6 cases (15%). c. ischemia were 5 cases (13%). d. normal were 5 cases (13%). In six cases of lacunar infarction which was double hypodensity on pre-and postcontrast CT

Clinical values of CT and dynamic CT in brain infarction

Energy Technology Data Exchange (ETDEWEB)

Lim, Soo Il; Jang, Do; Seo, Eun Joo; Sohn, Myung Hee; Choi, Ki Chul [Chonbuk National University College of Medicine, Jeonju (Korea, Republic of)

1985-04-15

With the advent of faster scan time and new computer program, a scanning technique called 'dynamic computed tomography' has become possible. Dynamic computed tomography consisted of performing multiple rapid sequence scans after injection of contrast material. The authors have evaluated the clinical usefulness of computed tomography and dynamic computed tomography of 93 patients with brain infarction and/or ischemia during the period of 17 months from April 1983 to August 1984 in Department of Radiology, Chonbuk National University Hospital. The results were as follows; 1. The age distribution ranged from 18 years to 78 years. Among them the most common age group was between 50 years and 59 years (40.9%). 2. The sites of brain infarction were cerebral lobes (63 cases,68), basal ganglia (15 cases, 16.1%) and multiple sites (6 cases, 6.4%). The common affected site was middle cerebral artery territories. 3. The contrast enhancement of acute infarction was noted in 14 cases (17.5%) which occurred commonly between 3 days and 2 weeks from ictus. 4. The patterns of time-density curve in brain infarction and/or ischemia were as follow: a. Depression of slow wash-in phase was 20 cases (59%). b. Lower peak concentration was 17 cases (50%). c. Lower and delayed peak concentration was 7 cases (21%). d. No definite peak concentration was 6 cases (18%). First three patterns of time-density curve were thought as relatively characteristic curve of brain infarction and/or ischemia. 5. Two cases that showed negative findings on precontrast CT scan appeared to be positive findings as hypodensity on postcontrast CT scan and were confirmed as brain infarction by dynamic CT. 6. The diagnostic entity of dynamic CT scan were as follows; a. large artery thrombotic infarction were 23 cases (58%). b. lacnar infarction were 6 cases (15%). c. ischemia were 5 cases (13%). d. normal were 5 cases (13%). In six cases of lacunar infarction which was double hypodensity on pre

INFORMATION DIMENSION VS COMMUNICATIVE DIMENSION EXTENDING THE CONCEPT OF DEFINITION AS WILL SWANSON ACTUALLY ALREADY OVERCOME?

Directory of Open Access Journals (Sweden)

Dulce María Sánchez-Cadena

2011-09-01

Full Text Available Achieve the development of a society entails actions that provide the optimal conditions to be achieved, without exception of sectors (economic, rural, social and coordinating these activities with the capabilities necessary to carry out and achieve the desired development. However, when development strategies are constructed errors of poorly defined concepts for practical and therefore activities focus only on one dimension, when they meet two what happens? We fall short on assigned tasks and consequently the results are not what they expected and planned development does not progress to the estimated speed.In this short letter, we will explore the definition given by extension Swanson reviewed the concepts that compose to discuss briefly information and communication terms of coverage, terms used on a daily basis in the extension activities undertaken in the field Mexican, and we review other positions to see if others Swanson's vision really is outdated or not.

Defining the Stakeholder Concept for Political Marketing

DEFF Research Database (Denmark)

Ormrod, Robert

The concept of a ‘stakeholder’ is often misused in the academic literature; stakeholders can range from the few actors with which the organisation has a direct interaction (Carroll 1993), to anything that can exert some form of influence over the organisation, including nature, the deceased...... and the unborn (Starik 1995). It is therefore necessary to provide a precise definition of the stakeholder concept to maintain academic rigour. However, a specification of the nature of the stakeholder concept is generally missing in political marketing literature. This paper addresses this issue by discussing...... how the stakeholder concept is understood, and then applies the stakeholder concept to the political marketing context, proposing a definition of the stakeholder concept for political marketing research....

Practical CT technology and techniques

International Nuclear Information System (INIS)

Berland, L.L.

1987-01-01

This handbook equips both radiologists and radiologists in training with a thorough working knowledge of the mechanisms and processes of computed tomography (CT) image generation, the common causes of image artifacts, and useful examination protocols for each area of the body. The author explains the fundamental technological principles of CT, focusing on those concepts crucial to successful CT examinations. The first part of the book succinctly reviews the fundamentals of CT technology. It begins with a methodical introduction to key principles of X-ray physics and technology, in which topics such as the modulation transfer function, magnification, and the X-ray tube are discussed in understandable, nonmathematical terms. The author then explains the basic technology of CT scanners, the principles of scan projection radiography, and the essential rules for radiation dosage determination and radiation protection. Careful attention is given to selectable scan factors in both routine and dynamic scanning, as well as to the processes involved in image creation and refinement and the chief determinants of image quality. Basic and specialized program features and the technology of image display, recording, and storage are also thoroughly described

Elaborating on Threshold Concepts

Science.gov (United States)

Rountree, Janet; Robins, Anthony; Rountree, Nathan

2013-01-01

We propose an expanded definition of Threshold Concepts (TCs) that requires the successful acquisition and internalisation not only of knowledge, but also its practical elaboration in the domains of applied strategies and mental models. This richer definition allows us to clarify the relationship between TCs and Fundamental Ideas, and to account…

A case study of analyzing student teachers' concept images of the ...

African Journals Online (AJOL)

This paper presents a tool for analyzing student teachers' concept images of the definite integral. The tool shows the basic concepts that underpin the concept of the definite integral and displays them in terms of process and object conceptions within various representations in the context of area under a curve. The use of ...

Technical principles of dual source CT

International Nuclear Information System (INIS)

Petersilka, Martin; Bruder, Herbert; Krauss, Bernhard; Stierstorfer, Karl; Flohr, Thomas G.

2008-01-01

During the past years, multi-detector row CT (MDCT) has evolved into clinical practice with a rapid increase of the number of detector slices. Today's 64 slice CT systems allow whole-body examinations with sub-millimeter resolution in short scan times. As an alternative to adding even more detector slices, we describe the system concept and design of a CT scanner with two X-ray tubes and two detectors (mounted on a CT gantry with a mechanical offset of 90 deg.) that has the potential to overcome limitations of conventional MDCT systems, such as temporal resolution for cardiac imaging. A dual source CT (DSCT) scanner provides temporal resolution equivalent to a quarter of the gantry rotation time, independent of the patient's heart rate (83 ms at 0.33 s rotation time). In addition to the benefits for cardiac scanning, it allows to go beyond conventional CT imaging by obtaining dual energy information if the two tubes are operated at different voltages. Furthermore, we discuss how both acquisition systems can be used to add the power reserve of two X-ray tubes for long scan ranges and obese patients. Finally, future advances of DSCT are highlighted

An evaluation of the variability of tumor-shape definition derived by experienced observers from CT images of supraglottic carcinomas (ACRIN protocol 6658)

International Nuclear Information System (INIS)

Cooper, Jay S.; Mukherji, Suresh K.; Toledano, Alicia Y.; Beldon, Clifford; Schmalfuss, Ilona M.; Amdur, Robert; Sailer, Scott; Loevner, Laurie A.; Kousouboris, Phil; Ang, K. Kian; Cormack, Jean; Sicks, JoRean M.S.

2007-01-01

Purpose: Accurate target definition is considered essential for sophisticated, image-guided radiation therapy; however, relatively little information has been reported that measures our ability to identify the precise shape of targets accurately. We decided to assess the manner in which eight 'experts' interpreted the size and shape of tumors based on 'real-life' contrast-enhanced computed tomographic (CT) scans. Methods and Materials: Four neuroradiologists and four radiation oncologists (the authors) with considerable experience and presumed expertise in treating head-and-neck tumors independently contoured, slice-by-slice, his/her interpretation of the precise gross tumor volume (GTV) on each of 20 sets of CT scans taken from 20 patients who previously were enrolled in Radiation Therapy Oncology Group protocol 91-11. Results: The average proportion of overlap (i.e., the degree of agreement) was 0.532 (95% confidence interval 0.457 to 0.606). There was a slight tendency for the proportion of overlap to increase with increasing average GTV. Conclusions: Our work suggests that estimation of tumor shape currently is imprecise, even for experienced physicians. In consequence, there appears to be a practical limit to the current trend of smaller fields and tighter margins

Representation of ophthalmology concepts by electronic systems: adequacy of controlled medical terminologies.

Science.gov (United States)

Chiang, Michael F; Casper, Daniel S; Cimino, James J; Starren, Justin

2005-02-01

To assess the adequacy of 5 controlled medical terminologies (International Classification of Diseases 9, Clinical Modification [ICD9-CM]; Current Procedural Terminology 4 [CPT-4]; Systematized Nomenclature of Medicine, Clinical Terms [SNOMED-CT]; Logical Identifiers, Names, and Codes [LOINC]; Medical Entities Dictionary [MED]) for representing concepts in ophthalmology. Noncomparative case series. Twenty complete ophthalmology case presentations were sequentially selected from a publicly available ophthalmology journal. Each of the 20 cases was parsed into discrete concepts, and each concept was classified along 2 axes: (1) diagnosis, finding, or procedure and (2) ophthalmic or medical concept. Electronic or paper browsers were used to assign a code for every concept in each of the 5 terminologies. Adequacy of assignment for each concept was scored on a 3-point scale. Findings from all 20 case presentations were combined and compared based on a coverage score, which was the average score for all concepts in that terminology. Adequacy of assignment for concepts in each terminology, based on a 3-point Likert scale (0, no match; 1, partial match; 2, complete match). Cases were parsed into 1603 concepts. SNOMED-CT had the highest mean overall coverage score (1.625+/-0.667), followed by MED (0.974+/-0.764), LOINC (0.781+/-0.929), ICD9-CM (0.280+/-0.619), and CPT-4 (0.082+/-0.337). SNOMED-CT also had higher coverage scores than any of the other terminologies for concepts in the diagnosis, finding, and procedure categories. Average coverage scores for ophthalmic concepts were lower than those for medical concepts. Controlled terminologies are required for electronic representation of ophthalmology data. SNOMED-CT had significantly higher content coverage than any other terminology in this study.

Automated quantification of emphysema in CT studies of the lung

International Nuclear Information System (INIS)

Archer, D.C.; deKemp, R.A.; Coblentz, C.L.; Nahmias, C.

1991-01-01

Emphysema by definition is a pathologic diagnosis. Recently, in vivo quantification of emphysema from CT with point counting and with a GE 9800 CT scanner program called Density Mask has been described. These methods are laborious and time-consuming, making them unsuitable for screening. The propose of this paper is to create a screening test for emphysema. The authors developed a computer program that quantifies the amount of emphysema from standard CT-scans. The computer was programmed to recognize the lung edges on each section by identifying abrupt changes in CT numbers; grow regions within each lung to identify and separate the lungs from other structures; count regions of lung containing CT numbers measuring <-900 HU corresponding to areas of emphysema; and calculation the percentage of emphysema present from the volume of normal emphysematous lung. The programs were written in C and urn on a Sun 4/100 workstation

The concept of a bilingual dictionary

DEFF Research Database (Denmark)

Tarp, Sven

2005-01-01

The term bilingual dictionary is widely used, not only by librarians and dictionary users en general but also by professional lexicographers dedicated to the theory and practice of dictionary making. For this reason it should be expected that there were a common and well-established definition...... of the concept of a bilingual dictionary. It is evident that most people has an intuitive idea of what is meant by «bilingual dictionary». But science-based lexicographic theory - at least if it wants to be considered as such - must go beyond intuition and furnish precise definitions of the concepts used...... chapters, various definitions will be discussed and related to dictionary practice and, subsequently, the very concept of a bilingual dictionary will be examined in the light of a dictionary typology based upon the modern theory of lexicographic functions....

Dose reduction strategies for cardiac CT

International Nuclear Information System (INIS)

Midgley, S.M.; Einsiedel, P.; Langenberg, F.; Lui, E.

2010-01-01

Full text: Recent advances in CT technology have produced brighter X-ray sources. gantries capable of increased rotation speeds, faster scintil lation materials arranged into multiple rows of detectors, and associated advances in 3D reconstruction methods. These innovations have allowed multi-detector CT to be turned to the diagnosis of cardiac abnormalities and compliment traditional imaging techniques such as coronary angiography. This study examines the cardiac imaging solution offered by the Siemens Somatom Definition Dual Source 64 slice CT scanner. Our dose reduction strategies involve optimising the data acquisition protocols according to diagnostic task, patient size and heart rate. The relationship between scan parameters, image quality and patient dose is examined and verified against measurements with phantoms representing the standard size patient. The dose reduction strategies are reviewed with reference to survey results of patient dose. Some cases allow the insertion of shielding to protect radiosensitive organs, and results are presented to quantify the dose saving.

Methods for CT automatic exposure control protocol translation between scanner platforms.

Science.gov (United States)

McKenney, Sarah E; Seibert, J Anthony; Lamba, Ramit; Boone, John M

2014-03-01

An imaging facility with a diverse fleet of CT scanners faces considerable challenges when propagating CT protocols with consistent image quality and patient dose across scanner makes and models. Although some protocol parameters can comfortably remain constant among scanners (eg, tube voltage, gantry rotation time), the automatic exposure control (AEC) parameter, which selects the overall mA level during tube current modulation, is difficult to match among scanners, especially from different CT manufacturers. Objective methods for converting tube current modulation protocols among CT scanners were developed. Three CT scanners were investigated, a GE LightSpeed 16 scanner, a GE VCT scanner, and a Siemens Definition AS+ scanner. Translation of the AEC parameters such as noise index and quality reference mAs across CT scanners was specifically investigated. A variable-diameter poly(methyl methacrylate) phantom was imaged on the 3 scanners using a range of AEC parameters for each scanner. The phantom consisted of 5 cylindrical sections with diameters of 13, 16, 20, 25, and 32 cm. The protocol translation scheme was based on matching either the volumetric CT dose index or image noise (in Hounsfield units) between two different CT scanners. A series of analytic fit functions, corresponding to different patient sizes (phantom diameters), were developed from the measured CT data. These functions relate the AEC metric of the reference scanner, the GE LightSpeed 16 in this case, to the AEC metric of a secondary scanner. When translating protocols between different models of CT scanners (from the GE LightSpeed 16 reference scanner to the GE VCT system), the translation functions were linear. However, a power-law function was necessary to convert the AEC functions of the GE LightSpeed 16 reference scanner to the Siemens Definition AS+ secondary scanner, because of differences in the AEC functionality designed by these two companies. Protocol translation on the basis of

Side-by-side reading of PET and CT scans in oncology: Which patients might profit from integrated PET/CT?

International Nuclear Information System (INIS)

Reinartz, Patrick; Wieres, Franz-Josef; Schneider, Wolfram; Schur, Alexander; Buell, Ulrich

2004-01-01

Most early publications on integrated positron emission tomography/computed tomography (PET/CT) devices have reported the new scanner generation to be superior to conventional PET. However, few of these studies have analysed the situation where, in addition to PET, a current CT scan is available for side-by-side viewing. This fact is important, because combined PET/CT or a software-based fusion of the two modalities may improve diagnosis only in cases where side-by-side reading of PET and CT data does not lead to a definitive diagnosis. The aim of this study was to analyse which patients will profit from integrated PET/CT in terms of lesion characterization. A total of 328 consecutively admitted patients referred for PET in whom a current CT scan was available were included in the study. The localization of all pathological PET lesions, as well as possible infiltration of adjacent anatomical structures, was assessed. Of 467 pathological lesions, 94.0% were correctly assessed with respect to localization and infiltration by either conventional PET alone (51.6%) or combined reading of PET and the already existing CT scans (42.4%). Hence, in only 6.0% of all lesions, affecting 6.7% of all patients, could evaluation have profited from integrated PET/CT. We conclude that side-by-side viewing of PET and CT scans is essential, as in 42.4% of all cases, combined viewing was important for a correct diagnosis in our series. In up to 6.7% of patients, integrated PET/CT might have given additional information, so that in nearly 50% of patients some form of combined viewing of PET and CT data is needed for accurate lesion characterization. (orig.)

How to use PET/CT in the evaluation of response to radiotherapy.

Science.gov (United States)

Decazes, Pierre; Thureau, Sébastien; Dubray, Bernard; Vera, Pierre

2017-11-28

Radiotherapy is a major treatment modality for many cancers. Tumor response after radiotherapy determines the subsequent steps of the patient's management (surveillance, adjuvant or salvage treatment and palliative care). Tumor response assessed during radiotherapy offers a promising opportunity to adapt the treatment plan to reduced / increased target volume, to specifically target sub-volumes with relevant biological characteristics (metabolism, hypoxia, proliferation ...) and to further spare the organs at risk. In addition to its role in the diagnosis and the initial staging, Positron Emission Tomography combined with a Computed Tomography (PET/CT) provides functional information and is therefore attractive to evaluate tumor response. To review the published data addressing PET/CT as an evaluation tool in irradiated tumors. Reports on PET/CT acquired at various times (during radiotherapy, after initial (chemo-)radiotherapy, after definitive radiotherapy and during posttreatment follow-up) in solid tumors (lung, head-and-neck, cervix, esophagus, prostate and rectum) were collected and reviewed. Various tracers and technical are also discussed. 18F-FDG PET/CT has a well-established role in clinical routine after definitive chemo-radiotherapy for locally advanced head-and-neck cancers. 18F-choline PET/CT is indicated in prostate cancer patients with biochemical failure. 18F-FDG PET/CT is optional in many others circumstances and the clinical benefits of assessing tumor response with PET/CT remain a field of very active research. The combination of PET with Magnetic Resonance Imaging (PET/MRI) may prove to be valuable in irradiated rectal and cervix cancers. Tumor response can be evaluated by PET/CT with clinical consequences in multiple situations, notably in head and neck and prostate cancers, after radiotherapy. Further clinical evaluation for most cancers is still needed, possibly in association to MRI.

Definitions Are Important: The Case of Linear Algebra

Science.gov (United States)

Berman, Abraham; Shvartsman, Ludmila

2016-01-01

In this paper we describe an experiment in a linear algebra course. The aim of the experiment was to promote the students' understanding of the studied concepts focusing on their definitions. It seems to be a given that students should understand concepts' definitions before working substantially with them. Unfortunately, in many cases they do…

Initial experience with FDG-PET/CT in the evaluation of breast cancer

International Nuclear Information System (INIS)

Tatsumi, Mitsuaki; Cohade, Christian; Mourtzikos, Karen A.; Wahl, Richard L.; Fishman, Elliot K.

2006-01-01

We retrospectively reviewed FDG-PET/CT images in patients with breast cancer to determine whether PET/CT improved the level of diagnostic confidence as compared with PET and to compare PET/CT and CT findings at the location of suspected malignancies. The study included 75 patients with known breast cancer. The initial PET/CT study for each patient was retrospectively reviewed to determine whether improved diagnostic confidence (IDC) regarding lesion localization and characterization was observed with PET/CT as compared with PET alone. PET/CT and CT findings were compared regarding lesion characterization and staging in 69 of the 75 patients, and in the case of discordant findings, comparison with histological or informative follow-up results was also performed. Fifty of the 75 patients exhibited increased FDG uptake in a total of 95 regions. In the comparison of PET/CT and PET, PET/CT resulted in IDC in 30 (60%) of these 50 patients and in 52 (55%) of the 95 regions. In the comparison between PET/CT and CT in 69 patients, PET/CT demonstrated a significantly better accuracy than CT (P<0.05). PET/CT showed definitely positive findings in 60 regions with malignancies, among which CT exhibited positive findings in 43 (72%). PET/CT and CT accurately staged 59 (86%) and 53 (77%) of the 69 patients, respectively. (orig.)

Automated size-specific CT dose monitoring program: Assessing variability in CT dose

International Nuclear Information System (INIS)

Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan

2012-01-01

Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED adj ). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED adj between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED adj that differed by up to 44% from effective dose estimates that were not

SPECT-CT bone scintigraphy in cancer patients

International Nuclear Information System (INIS)

Sergieva, S; Alexandrova, A.; Nikolova, N.; Dimcheva, M.; Baichev, G.

2012-01-01

Full text: Introduction: SPECT-CT study allows the precise correlation between functional and morphological data on the same image. Methods: Whole body bone scan (WBBS) is a diagnostic modality still firmly established as a valuable tool to assess skeleton abnormalities. CT is an imaging method for characterizing destruction of the bone spongy lesions, their consolidation or calcium accumulation. This fact allows differentiation of the osteolytic metastases from the osteosclerotic and mixed lesions and also from degenerative ones. Whole body bone scan followed by SPECT-CT scanning increases the accuracy of the study and potentially accelerates the diagnosis of the patient based on a single imaging session. This is especially important in cancer patients. Results and discussion: After retrospectively review of WBBS and SPECT-CT fused images 141 bone lesions in 89 pts were analyzed The skeletal findings with previously uncertain character were classified as definitely benign, indeterminate or definitely malignant. 1. 47 (33%) of all lesions in 36 pts could be correlated with benign degenerative findings on SPECT-CT images. 5 (3%) lesions in 3 of these pts were indeterminate on the SPECT-CT images. They were localized in the area of articulation parts and corpus of the thoracic vertebra and ribs. After additional MRT examination and 6 months follow-up these changes were considered degenerative: osteopathy changes and presence of spondyloarthrosis and osteochondrosis; compression fractures due to advanced osteoporosis. These pts were with prolonged chormono/chemotherapy; chronic inflammatory disease of the coxofemoral articulation, coxarthrosis, aseptic necrosis of the femoral head and postoperative sacroiliitis; post-traumatic fractures or surgical intervention; hyperplastic degenerative lesions in the skeleton and asymmetrical pelvic bone structures due to M. Paget. 2. 41 (28,1%) single osseous metastatic spots (up to 3 foci) were scanned in 31 pts. 3. 13 (10

Clinical value of {sup 18}F-fluorodihydroxyphenylalanine positron emission tomography/computed tomography ({sup 18}F-DOPA PET/CT) for detecting pheochromocytoma

Energy Technology Data Exchange (ETDEWEB)

Luster, Markus; Zeich, Katrin; Glatting, Gerhard; Buck, Andreas K.; Solbach, Christoph; Reske, Sven N. [University of Ulm, Department of Nuclear Medicine, Ulm (Germany); Karges, Wolfram [RWTH Aachen, Division of Endocrinology and Diabetes, Aachen (Germany); Pauls, Sandra [University of Ulm, Department of Radiology, Ulm (Germany); Verburg, Frederik A. [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Dralle, Henning [University Halle-Wittenberg, Department of General, Visceral and Vascular Surgery, Halle (Germany); Neumaier, Bernd [University of Ulm, Department of Nuclear Medicine, Ulm (Germany); Max-Planck-Institut fuer Neurologische Forschung, Section for Radiochemistry, Cologne (Germany); Mottaghy, Felix M. [University of Ulm, Department of Nuclear Medicine, Ulm (Germany); RWTH Aachen, Department of Nuclear Medicine, Aachen (Germany)

2010-03-15

In detecting pheochromocytoma (PHEO), positron emission tomography (PET) with the radiolabelled amine precursor {sup 18}F-fluorodihydroxyphenylalanine ({sup 18}F-DOPA) offers excellent specificity, while computed tomography (CT) provides high sensitivity and ability to localize lesions; therefore, the combination of these modalities could be advantageous in this setting. The aim of this study was to investigate whether combined {sup 18}F-DOPA PET/CT more accurately detects and localizes PHEO lesions than does each modality alone. {sup 18}F-DOPA PET, CT and {sup 18}F-DOPA PET/CT images of 25 consecutive patients undergoing diagnostic scanning of suspected sporadic or multiple endocrine neoplasia type 2 syndrome-associated PHEO were reviewed retrospectively in randomized sequence. Two blinded observers scored the images regarding the likelihood of PHEO being present and localizable. Results were correlated with subsequent clinical history and, when available, histology. Of the 19 lesions detected by all three modalities, PET identified each as positive for PHEO, but was unable to definitively localize 15 of 19 (79%). CT could definitively localize all 19 lesions, but could not definitively diagnose or exclude PHEO in 18 of 19 (95%) lesions. Furthermore, CT falsely identified as negative for PHEO one lesion which was judged to be positive for this tumor by both PET and PET/CT. Only in PET/CT scans were all 19 lesions accurately characterized and localized. On a per-patient basis, the sensitivity of {sup 18}F-DOPA PET/CT for PHEO was 100% and the specificity 88%, with a 100% positive predictive value and an 88% negative predictive value. {sup 18}F-DOPA PET/CT more accurately diagnoses and localizes adrenal and extra-adrenal masses suspicious for PHEO than do {sup 18}F-DOPA PET or CT alone. (orig.)

Empowerment: a Concept Analysis

OpenAIRE

Febriana, Dara

2011-01-01

This paper conceptually analyzed the concept of empowerment using the strategies of Walker & Avant (2005) the objective is to clarify the meaning of the concept and to clearly identify empowerment characteristic that will provide consistent definition for practice and future research. Empowerment is defined and examined using relevant resources of literatures and selected empirical referents that described empowerment as a complex and multidimensional concept. Within nursing context empowerme...

Case report: Isolated unilateral pulmonary vein atresia diagnosed on 128-slice multidetector CT

Directory of Open Access Journals (Sweden)

Rashmi Dixit

2011-01-01

Full Text Available Unilateral pulmonary venous atresia is an uncommon entity that is generally believed to be congenital. Most patients present in infancy or childhood with recurrent chest infections or hemoptysis. Pulmonary angiography is usually used for definitive diagnosis. However, the current multislice CT scanners may obviate the need for pulmonary angiography. We report two cases diagnosed using 128-slice CT angiography. On the CT angiography images both these cases demonstrated absent pulmonary veins on the affected side, with a small pulmonary artery and prominent bronchial or other systemic arterial supply.

Refined staging in hilar bronchial neoplasms with ECG-gated multislice-CT. Case report

International Nuclear Information System (INIS)

Ohlmann, S.; Daliri, A.; Froelich, J.J.; Nowak, R.; Michulla, R.

2008-01-01

Equivocal initial CT-based staging in 2 patients with hilar bronchial neoplasms was reassessed with retrospective ECG-gated Multislice-CT and optimized examination parameters prior to definition of treatment. An initially suspected irresectable T 4 tumor with mediastinal infiltration was downstaged to T 2 in one case, while tumor infiltration into the left atrium could be confirmed in the other case. In doubtful conditions, ECG-gated multislice CT with optimized examination parameters may be helpful for refined staging in patients with hilar bronchial neoplasma, thus possibly influencing treatment strategies. (orig.)

The relationship between image quality and trial slits CT-1010

International Nuclear Information System (INIS)

Yoshinaga, Toshihiko; Nakamura, Sumio; Kakoi, Iwao; Ohkubo, Mitsuo; Tomiyoshi, Tsukasa

1980-01-01

We had used trial slits for EMI scanner CT-1010 and CT images of good quality almost free artifacts could be obtained when the slice thickness decreased to 5 mm. In this study, we experimented changes of MTF (modulation transfer function) as the slice thickness changed. As a result, MTF got worse as the slice thickness decreased, but got better as the exposure dose increased. The high accuracy high definitions of a 10 mm slice thickness and a 5 mm one were nearly equal in MTF. (author)

Conventional 3D staging PET/CT in CT simulation for lung cancer: impact of rigid and deformable target volume alignments for radiotherapy treatment planning.

Science.gov (United States)

Hanna, G G; Van Sörnsen De Koste, J R; Carson, K J; O'Sullivan, J M; Hounsell, A R; Senan, S

2011-10-01

Positron emission tomography (PET)/CT scans can improve target definition in radiotherapy for non-small cell lung cancer (NSCLC). As staging PET/CT scans are increasingly available, we evaluated different methods for co-registration of staging PET/CT data to radiotherapy simulation (RTP) scans. 10 patients underwent staging PET/CT followed by RTP PET/CT. On both scans, gross tumour volumes (GTVs) were delineated using CT (GTV(CT)) and PET display settings. Four PET-based contours (manual delineation, two threshold methods and a source-to-background ratio method) were delineated. The CT component of the staging scan was co-registered using both rigid and deformable techniques to the CT component of RTP PET/CT. Subsequently rigid registration and deformation warps were used to transfer PET and CT contours from the staging scan to the RTP scan. Dice's similarity coefficient (DSC) was used to assess the registration accuracy of staging-based GTVs following both registration methods with the GTVs delineated on the RTP PET/CT scan. When the GTV(CT) delineated on the staging scan after both rigid registration and deformation was compared with the GTV(CT)on the RTP scan, a significant improvement in overlap (registration) using deformation was observed (mean DSC 0.66 for rigid registration and 0.82 for deformable registration, p = 0.008). A similar comparison for PET contours revealed no significant improvement in overlap with the use of deformable registration. No consistent improvements in similarity measures were observed when deformable registration was used for transferring PET-based contours from a staging PET/CT. This suggests that currently the use of rigid registration remains the most appropriate method for RTP in NSCLC.

Power: towards a third generation definition

OpenAIRE

13250612 - Zaaiman, Stephanus Johannes

2008-01-01

Power is a well-established concept in the social sciences especially in the political sciences. Although it is widely used in scientific discourse, different definitions and perspectives prevail with regard to it. This article aims to explore the possibilities of taking the debate further towards a third generation definition of social power. Although first generation definitions (associated with Weber and Dahl) and second generation definitions (associated with inter alia Giddens and Morris...

Studies on CT findings and operation findings for acute appendicitis in children

International Nuclear Information System (INIS)

Sakakibara, Kenichi; Andoh, Shigemitsu; Karamatsu, Syouji; Urakami, Toshihiko; Tsuji, Hideki; Kobayashi, Tohru; Okahira, Kihiro

1995-01-01

Pediatric CT findings of acute appendicitis were reviewed retrospectively. The subjects were 29 patients (15 boys and 14 girls with an average age of 8.2 years), consisting of 17 with necrotic, 8 with phlegmonous inflammatory, and 4 with catarrhal appendicitis. CT findings were compared with the degree of inflammation. CT revealed abscess in 64.7%, 12.5%, and 0% for necrotic, phlegmonous inflammatory, and catarrhal types, respectively, and 41.4% for all types. An enlarged appendicitis was shown on CT in 86.2% (25/29). Fecalithes were shown on CT in 67.7% (19/29), which was associated with necrotic and phlegmonous inflammatory types, but not with catarrhal type. The other CT findings included thickened paramesocolon of the right lower abdomen, undefined wall of the inner side of the cecum. Inflammation was relatively slight in cases of catarrhal appendicitis, Nine patients less than 5 years of age had phlegmonous inflammatory or necrotic appendicitis. CT allowed definitive diagnosis of appendicitis in 2 of 3 patients with necrotic type. Ct was considered to be very useful in the diagnosis of appendicitis. (N.K.)

Social Accountable Medical Education: A concept analysis.

Science.gov (United States)

Abdolmaleki, Mohammadreza; Yazdani, Shahram; Momeni, Sedigheh; Momtazmanesh, Nader

2017-07-01

Considering the pervasiveness of social accountable medical education concept around the world and the growing trend of literature in this regard as well as various interpretations made about this concept, we found it necessary to analyze the concept of social accountable medical education. In this study, the modified version of McKenna's approach to concept analysis was used to determine the concept, explain structures and substructures and determine the border concepts neighboring and against social accountability in medical education. By studying the selected sources,the components of the concept were obtained to identify it and express an analytic definition of social accountability in medical education system. Then, a model case with all attributes of the given concept and the contrary and related concepts were mentioned to determine the boundary between the main concept and auxiliary ones. According to the results of this study in the field of social accountability, the detailed and transparent analytical definition of social accountable medical education can be used in future studies as well as the function and evaluation of medical education system.

Refinement of the concept of uncertainty.

Science.gov (United States)

Penrod, J

2001-04-01

To analyse the conceptual maturity of uncertainty; to develop an expanded theoretical definition of uncertainty; to advance the concept using methods of concept refinement; and to analyse congruency with the conceptualization of uncertainty presented in the theory of hope, enduring, and suffering. Uncertainty is of concern in nursing as people experience complex life events surrounding health. In an earlier nursing study that linked the concepts of hope, enduring, and suffering into a single theoretical scheme, a state best described as 'uncertainty' arose. This study was undertaken to explore how this conceptualization fit with the scientific literature on uncertainty and to refine the concept. Initially, a concept analysis using advanced methods described by Morse, Hupcey, Mitcham and colleagues was completed. The concept was determined to be partially mature. A theoretical definition was derived and techniques of concept refinement using the literature as data were applied. The refined concept was found to be congruent with the concept of uncertainty that had emerged in the model of hope, enduring and suffering. Further investigation is needed to explore the extent of probabilistic reasoning and the effects of confidence and control on feelings of uncertainty and certainty.

Who and Racist criteria on CT

International Nuclear Information System (INIS)

Servente, L.

2012-01-01

This presentation is about Who and Recist criteria on CT.These are rules to the evaluation of the solid tumors treatment response as well as different concepts of measurability criteria of blastic changes, target /non target lesions, adenopathies, lytic, cystic , non-measurable disease and progressive lesions

Conceptualising Business Models: Definitions, Frameworks and Classifications

Directory of Open Access Journals (Sweden)

Erwin Fielt

2013-12-01

Full Text Available The business model concept is gaining traction in different disciplines but is still criticized for being fuzzy and vague and lacking consensus on its definition and compositional elements. In this paper we set out to advance our understanding of the business model concept by addressing three areas of foundational research: business model definitions, business model elements, and business model archetypes. We define a business model as a representation of the value logic of an organization in terms of how it creates and captures customer value. This abstract and generic definition is made more specific and operational by the compositional elements that need to address the customer, value proposition, organizational architecture (firm and network level and economics dimensions. Business model archetypes complement the definition and elements by providing a more concrete and empirical understanding of the business model concept. The main contributions of this paper are (1 explicitly including the customer value concept in the business model definition and focussing on value creation, (2 presenting four core dimensions that business model elements need to cover, (3 arguing for flexibility by adapting and extending business model elements to cater for different purposes and contexts (e.g. technology, innovation, strategy (4 stressing a more systematic approach to business model archetypes by using business model elements for their description, and (5 suggesting to use business model archetype research for the empirical exploration and testing of business model elements and their relationships.

A short comparison between mT2 and mCT

International Nuclear Information System (INIS)

Serna, Mario

2008-01-01

We compare m T2 with m CT ; both are kinematic variables designed to find relationships between masses of pair-produced new states with symmetric decay chains. We find that for massless visible particles m CT equals m T2 in a particular limit. We identify advantages and disadvantages to the use of each variable. Tovey's paper on m CT also introduced a powerful concept of extracting mass information from an analysis at intermediate stages of a symmetric decay chain. We suggest that m T2 is a better tool for performing this analysis than m CT due to m T2 's better properties under initial state radiation.

CT outperforms radiographs at a comparable radiation dose in the assessment for spondylolysis.

Science.gov (United States)

Fadell, Michael F; Gralla, Jane; Bercha, Istiaq; Stewart, Jaime R; Harned, Roger K; Ingram, James D; Miller, Angie L; Strain, John D; Weinman, Jason P

2015-07-01

Lumbar spondylolysis, a unilateral or bilateral fracture at pars interarticularis, is a common cause of low back pain in children. The initial imaging study in the diagnosis of lumbar spondylolysis has historically been lumbar spine radiographs; however, radiographs can be equivocal or false-negative. Definitive diagnosis can be achieved with computed tomography (CT), but its use has been limited due to the dose of ionizing radiation to the patient. By limiting the z-axis coverage to the relevant anatomy and optimizing the CT protocol, we are able to provide a definitive diagnosis of fractures of the pars interarticularis at comparable or lower radiation dose than commonly performed lumbar spine radiographs. As there is no gold standard for the diagnosis of spondylolysis besides surgery, we compared interobserver agreement and degree of confidence to determine which modality is preferable. Sixty-two patients with low back pain ages 5-18 years were assessed for the presence of spondylolyis. Forty-seven patients were evaluated by radiography and 15 patients were evaluated by limited field-of-view CT. Both radiographic and CT examinations were assessed anonymously in random order for the presence or absence of spondylolyisis by six raters. Agreement was assessed among raters using a Fleiss Kappa statistic for multiple raters. CT provided a significantly higher level of agreement among raters than radiographs (P < 0.001). The overall Kappa for rater agreement with radiographs was 0.24, 0.34 and 0.40 for 2, 3 or 4 views, respectively, and 0.88 with CT. Interobserver agreement is significantly greater using limited z-axis coverage CT when compared with radiographs. Radiologist confidence improved significantly with CT compared to radiographs regardless of the number of views.

CT outperforms radiographs at a comparable radiation dose in the assessment for spondylolysis

Energy Technology Data Exchange (ETDEWEB)

Fadell, Michael F.; Stewart, Jaime R.; Harned, Roger K.; Ingram, James D.; Miller, Angie L.; Strain, John D.; Weinman, Jason P. [Children' s Hospital Colorado, Department of Radiology, Aurora, CO (United States); University of Colorado Hospital, Department of Radiology, Aurora, CO (United States); Gralla, Jane [University of Colorado Denver, Department of Pediatrics, Aurora, CO (United States); Bercha, Istiaq [Children' s Hospital Colorado, Department of Radiology, Aurora, CO (United States)

2015-07-15

Lumbar spondylolysis, a unilateral or bilateral fracture at pars interarticularis, is a common cause of low back pain in children. The initial imaging study in the diagnosis of lumbar spondylolysis has historically been lumbar spine radiographs; however, radiographs can be equivocal or false-negative. Definitive diagnosis can be achieved with computed tomography (CT), but its use has been limited due to the dose of ionizing radiation to the patient. By limiting the z-axis coverage to the relevant anatomy and optimizing the CT protocol, we are able to provide a definitive diagnosis of fractures of the pars interarticularis at comparable or lower radiation dose than commonly performed lumbar spine radiographs. As there is no gold standard for the diagnosis of spondylolysis besides surgery, we compared interobserver agreement and degree of confidence to determine which modality is preferable. Sixty-two patients with low back pain ages 5-18 years were assessed for the presence of spondylolysis. Forty-seven patients were evaluated by radiography and 15 patients were evaluated by limited field-of-view CT. Both radiographic and CT examinations were assessed anonymously in random order for the presence or absence of spondylolysis by six raters. Agreement was assessed among raters using a Fleiss Kappa statistic for multiple raters. CT provided a significantly higher level of agreement among raters than radiographs (P < 0.001). The overall Kappa for rater agreement with radiographs was 0.24, 0.34 and 0.40 for 2, 3 or 4 views, respectively, and 0.88 with CT. Interobserver agreement is significantly greater using limited z-axis coverage CT when compared with radiographs. Radiologist confidence improved significantly with CT compared to radiographs regardless of the number of views. (orig.)

CT outperforms radiographs at a comparable radiation dose in the assessment for spondylolysis

International Nuclear Information System (INIS)

Fadell, Michael F.; Stewart, Jaime R.; Harned, Roger K.; Ingram, James D.; Miller, Angie L.; Strain, John D.; Weinman, Jason P.; Gralla, Jane; Bercha, Istiaq

2015-01-01

Lumbar spondylolysis, a unilateral or bilateral fracture at pars interarticularis, is a common cause of low back pain in children. The initial imaging study in the diagnosis of lumbar spondylolysis has historically been lumbar spine radiographs; however, radiographs can be equivocal or false-negative. Definitive diagnosis can be achieved with computed tomography (CT), but its use has been limited due to the dose of ionizing radiation to the patient. By limiting the z-axis coverage to the relevant anatomy and optimizing the CT protocol, we are able to provide a definitive diagnosis of fractures of the pars interarticularis at comparable or lower radiation dose than commonly performed lumbar spine radiographs. As there is no gold standard for the diagnosis of spondylolysis besides surgery, we compared interobserver agreement and degree of confidence to determine which modality is preferable. Sixty-two patients with low back pain ages 5-18 years were assessed for the presence of spondylolysis. Forty-seven patients were evaluated by radiography and 15 patients were evaluated by limited field-of-view CT. Both radiographic and CT examinations were assessed anonymously in random order for the presence or absence of spondylolysis by six raters. Agreement was assessed among raters using a Fleiss Kappa statistic for multiple raters. CT provided a significantly higher level of agreement among raters than radiographs (P < 0.001). The overall Kappa for rater agreement with radiographs was 0.24, 0.34 and 0.40 for 2, 3 or 4 views, respectively, and 0.88 with CT. Interobserver agreement is significantly greater using limited z-axis coverage CT when compared with radiographs. Radiologist confidence improved significantly with CT compared to radiographs regardless of the number of views. (orig.)

PET/CT-guided biopsies of metabolically active bone lesions: applications and clinical impact

Energy Technology Data Exchange (ETDEWEB)

Klaeser, Bernd; Wartenberg, Jan; Weitzel, Thilo; Krause, Thomas [Bern University Hospital and University of Bern, Department of Nuclear Medicine, Inselspital, Bern (Switzerland); Wiskirchen, Jakub [Bern University Hospital and University of Bern, Department of Nuclear Medicine, Inselspital, Bern (Switzerland); University Hospital Tuebingen, Department of Radiology, Neuroradiology, and Nuclear Medicine, Tuebingen (Germany); Schmid, Ralph A. [Bern University Hospital and University of Bern, Department of Thoracic Surgery, Inselspital, Bern (Switzerland); Mueller, Michel D. [Bern University Hospital and University of Bern, Department of Obstetrics and Gynaecology, Inselspital, Bern (Switzerland)

2010-11-15

In a minority of cases a definite diagnosis and stage grouping in cancer patients is not possible based on the imaging information of PET/CT. We report our experience with percutaneous PET/CT-guided bone biopsies to histologically verify the aetiology of hypermetabolic bone lesions. We retrospectively reviewed the data of 20 consecutive patients who underwent multimodal image-guided bone biopsies using a dedicated PET/CT system in a step-by-step technique. Technical and clinical success rates of PET/CT-guided biopsies were evaluated. Questionnaires were sent to the referring physicians to assess the impact of biopsies on patient management and to check the clinical need for PET/CT-guided biopsies. Clinical indications for biopsy were to histologically verify the aetiology of metabolically active bone lesions without a morphological correlate confirming the suspicion of metastases in 15 patients, to determine the origin of suspected metastases in 3 patients and to evaluate the appropriateness of targeted therapy options in 2 patients. Biopsies were technically successful in all patients. In 19 of 20 patients a definite histological diagnosis was possible. No complications or adverse effects occurred. The result of PET/CT-guided bone biopsies determined a change of the planned treatment in overall 56% of patients, with intramodality changes, e.g. chemotherapy with palliative instead of curative intent, and intermodality changes, e.g. systemic therapy instead of surgery, in 22 and 50%, respectively. PET/CT-guided bone biopsies are a promising alternative to conventional techniques to make metabolically active bone lesions - especially without a distinctive morphological correlate - accessible for histological verification. PET/CT-guided biopsies had a major clinical impact in patients who otherwise cannot be reliably stage grouped at the time of treatment decisions. (orig.)

Cyberbullying in Adolescence: A Concept Analysis.

Science.gov (United States)

Hutson, Elizabeth

2016-01-01

The aim of this article was to present a detailed analysis of the concept of cyberbullying. Research on the topic of cyberbullying is growing exponentially, but not all studies use the same definition to examine this concept. A concept analysis in the style of Walker and Avant was used to analyze cyberbullying. Literature was retrieved from the databases of CINAHL and PubMed between the years 2009 and October 2014 using the key word "cyberbullying." Twenty-five English-language articles were located that delineated a definition of cyberbullying. First, articles were analyzed to discover the defining attributes of cyberbullying. Second, antecedents, consequences, and related terms of cyberbullying were examined. Third, an operational definition of cyberbullying is proposed on the basis of a consensus of the review. This review proposes that the defining attributes of cyberbullying are: (1) electronic form of contact (2) an aggressive act (3) intent (4) repetition (publicity), and (5) harm of the victim. The antecedents most often mentioned were lower self-esteem, higher levels of depression, and social isolation and the consequences were academic problems and affective disorders. A single concise definition of cyberbullying was created that can be utilized by health care providers to educate their patients and families about cyberbullying. This definition also can be used to guide research to develop effective interventions.

Definition of IGRT

International Nuclear Information System (INIS)

Lief, Eugene

2008-01-01

Two definitions of image-guided radiation therapy (IGRT) are cited: 'Frequent imaging in the treatment room during a course of radiotherapy to guide the treatment process' and 'Any use of planar imaging, volumetric imaging or volumetric cine imaging, marker localization, marker tracking, patient surface imaging or patient surface tracking to improve the precision of radiation-therapy delivery'. Also cited are the sentences 'IGRT refers broadly to treatment delivery using modern imaging methods, such as CT, MRI, PET and Ultrasound, in target and non-target structures and in RT definition, design and delivery...' and 'IGRT includes, but is not limited to, 3DCRT, IMRT: stereotactic radiosurgery, stereotactic RT, and brachytherapy...'. Purposes include: Precise patient positioning; Automatic localization of bony structures or implanted fiducial markers; Imaging and positioning of soft tissue tumors and critical structures; Margin reduction and healthy organ sparing; and Delivering the desired dose distribution. On the negative side are the following factors: Physics staffing at treatment delivery Longer treatment times: 1 min. arm deployment, setup for scan, 1 min. gantry rotation - volume image acquisition, 30 sec. reconstruction (depends on resolution), 30 sec. load CT and CB into registration; Registration: from few sec. to few min.; Feasible if the number of treatments is low. The history of IGRT is mentioned, instrumentation is described using ample photographs, and many applications are shown. (P.A.)

Noninvasive diagnosis of suspected severe pulmonary embolism. Trans-esophageal echocardiography vs spiral CT

International Nuclear Information System (INIS)

Pruszczyk, P.; Torbicki, A.; Pacho, R.

1998-01-01

Patients with pulmonary embolism (PE) and echocardiographic signs of right ventricular over-lead have worse prognosis and may be require aggressive therapy. Unequivocal confirmation of PE is required before thrombolysis or embolectomy. This study compares the value of trans-esophageal echocardiography (TEE) and spiral CT (sCT) in direct visualization of pulmonary artery thrombo-emboli in patients with suspected PE and echocardiographic signs of right ventricular over-lead. Because of high prevalence of bilateral central pulmonary thrombo-emboli in patients with hemo-dynamically significant PE, both sCT and TEE allow its definitive confirmation in most cases. Thrombi reported by sCT distally to lobar arteries should be interpreted with caution. (author)

Integrated technology rotor/flight research rotor hub concept definition

Science.gov (United States)

Dixon, P. G. C.

1983-01-01

Two variations of the helicopter bearingless main rotor hub concept are proposed as bases for further development in the preliminary design phase of the Integrated Technology Rotor/Flight Research Rotor (ITR/FRR) program. This selection was the result of an evaluation of three bearingless hub concepts and two articulated hub concepts with elastomeric bearings. The characteristics of each concept were evaluated by means of simplified methodology. These characteristics included the assessment of stability, vulnerability, weight, drag, cost, stiffness, fatigue life, maintainability, and reliability.

Interobserver and intermodality variability in GTV delineation on simulation CT, FDG-PET, and MR Images of Head and Neck Cancer.

Science.gov (United States)

Anderson, Carryn M; Sun, Wenqing; Buatti, John M; Maley, Joan E; Policeni, Bruno; Mott, Sarah L; Bayouth, John E

2014-09-01

To compare the interobserver and intermodality differences in image-based identification of head and neck primary site gross tumor volumes (GTV). Modalities compared include: contrast-enhanced CT, F-18 fluorodeoxyglucose positron emission tomography (PET/CT) and contrast-enhanced MRI. Fourteen patients were simulated after immobilization for all 3 imaging modalities (CT, PET/CT, MRI). Three radiation oncologists (RO) contoured GTVs as seen on each modality. The GTV was contoured first on the contrast-enhanced CT (considered the standard), then on PET/CT, and finally on post-contrast T1 MRI. Interobserver and intermodality variability were analyzed by volume, intersection, union, and volume overlap ratio (VOR). Analysis of RO contours revealed the average volume for CT-, PET/CT-, and MRI-derived GTVs were 45cc, 35cc and 49cc, respectively. In 93% of cases PET/CT-derived GTVs had the smallest volume and in 57% of cases MRI-derived GTVs had the largest volume. CT showed the largest variation in target definition (standard deviation amongst observers 35%) compared to PET/CT (28%) and MRI (27%). The VOR was largest (indicating greatest interobserver agreement) in PET/CT (46%), followed by MRI (36%), followed by CT (34%). For each observer, the least agreement in GTV definition occurred between MRI & PET/CT (average VOR = 41%), compared to CT & PET/CT (48%) and CT & MRI (47%). A nonsignificant interobserver difference in GTVs for each modality was seen. Among three modalities, CT was least consistent, while PET/CT-derived GTVs had the smallest volumes and were most consistent. MRI combined with PET/CT provided the least agreement in GTVs generated. The significance of these differences for head & neck cancer is important to explore as we move to volume-based treatment planning based on multi-modality imaging as a standard method for treatment delivery.

Ontological Analysis of the Project Risk Management Concept ‘Risk’

Directory of Open Access Journals (Sweden)

Uzulāns Juris

2018-02-01

Full Text Available The aim of the current research series is to examine the definitions of the concept ‘risk’ and analyze the concepts used in the definitions of ‘risk’ in the sources of these definitions in order to perform the ontological analysis of the concept of ‘risk’. Ontological and epistemological analysis of the concepts in the definition of the concept ‘risk’ was used to answer the question what ‘risk’ means in project management. This investigation represents a part of the research series where the ontological, epistemological and methodological analysis of project risk is performed with the aim to improve risk registers and risk management as a whole. In the previous studies the author analyzed the concept of ‘event’ that defines the content of the concept ‘risk’. The use of ‘event’ was analyzed in different sources to find out how the concept should be used. The ontological, epistemological and methodological analysis of the definitions of the concept ‘risk’ is the theoretical foundation for risk register creation because it is possible to create complete and understandable register for the participants of the project risk management process. The author believes that the conducted research helps establish confidence that ontological analysis is the method that together with the epistemological and methodological analysis provides opportunity to perform analysis of risk management sources aimed at improving risk management. The results of the study cannot be considered sufficient for deriving valid conclusions about project risk management and developing recommendations for improving risk management with regard to the content of the risk register. For valid conclusions and recommendations, a deeper research is needed which, first of all, would analyze a larger number of sources.

Study of CT and etiology In 11B cases of eoute headache without hemlplegla

Institute of Scientific and Technical Information of China (English)

Daoming Tong

2000-01-01

objectal To study the relation between CT and etiology of acute headache without hemiplegia. Methods 118 cases of acute headache without hemiplegia were studied with CT scan. The patients with normal CT were diagnosed with lumbar punc -tura or diagnostic standard for establishing disease. Results The first three etiologies were cerebrovescular disease (65 cases, 55%), migraine (25 cases, 21%), meningitis and encephalitis (19 cases, 155. 9%). 53% of patients with subarachnoid hemorrhage(SAH) was diagnosed in CT unnormal group, and 12.4% of patients with Sall was showed by lumbar puncture in CT normal group(P＜0. 001). CT was normal in 18% of patients with a definite SAH(7/39). The positive rates of intracranial infection in CT normal group(by lumbar puncture) was reearkably higher than in CT unnormal group (18/58 versus 2/60, p＜0.005), Conolusion CT is more sensitive to intracranial hemorrhage, tumor and infarction. SAH of a negative Ctscan is not rare. CT is far inferior to lumbar puncture in meningitis or encephalitis.

Comparison of CT findings with upper GI series and surgical findings

Energy Technology Data Exchange (ETDEWEB)

Hong, Jin Kyo; Suh, Soo Jhi; Kim, Soon Yong [School of Medicine, Kyung Hee University, Seoul (Korea, Republic of)

1981-09-15

The authors made comparative studies of CT findings with upper GI series and surgical findings in 20 cases of histologically proven gastric cancers. The identification of chickening of gastric wall and local and remote metastasis by CT was thought to be great value in treatment planning and prediction of prognosis of the patients. The results were as follows: 1. Of 20 cases, 19 cases demonstrated thickening of gastric wall. Among 3 cases suggested as early cancer on upper GI series, 2 cases demonstrated thickened gastric wall on CT and it was proved to be advanced cancer at surgery. 2. Out of 8 cases showed no definite metastasis on CT, 4 cases had malignant infiltration histologically in the regional lymph nodes. But they were less than 1.5 cm in diameter. 3. The frequency order of remote metastasis found by CT was pancreas, liver, left adrenal gland and lung in organs and retroperitoneal, retrocrural and regional nodes in lymph nodes.

Automated size-specific CT dose monitoring program: Assessing variability in CT dose

Energy Technology Data Exchange (ETDEWEB)

Christianson, Olav; Li Xiang; Frush, Donald; Samei, Ehsan [Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 and Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States) and Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Clinical Imaging Physics Group, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27705 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27710 (United States); and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States)

2012-11-15

Purpose: The potential health risks associated with low levels of ionizing radiation have created a movement in the radiology community to optimize computed tomography (CT) imaging protocols to use the lowest radiation dose possible without compromising the diagnostic usefulness of the images. Despite efforts to use appropriate and consistent radiation doses, studies suggest that a great deal of variability in radiation dose exists both within and between institutions for CT imaging. In this context, the authors have developed an automated size-specific radiation dose monitoring program for CT and used this program to assess variability in size-adjusted effective dose from CT imaging. Methods: The authors radiation dose monitoring program operates on an independent health insurance portability and accountability act compliant dosimetry server. Digital imaging and communication in medicine routing software is used to isolate dose report screen captures and scout images for all incoming CT studies. Effective dose conversion factors (k-factors) are determined based on the protocol and optical character recognition is used to extract the CT dose index and dose-length product. The patient's thickness is obtained by applying an adaptive thresholding algorithm to the scout images and is used to calculate the size-adjusted effective dose (ED{sub adj}). The radiation dose monitoring program was used to collect data on 6351 CT studies from three scanner models (GE Lightspeed Pro 16, GE Lightspeed VCT, and GE Definition CT750 HD) and two institutions over a one-month period and to analyze the variability in ED{sub adj} between scanner models and across institutions. Results: No significant difference was found between computer measurements of patient thickness and observer measurements (p= 0.17), and the average difference between the two methods was less than 4%. Applying the size correction resulted in ED{sub adj} that differed by up to 44% from effective dose

Conceptualising Business Models: Definitions, Frameworks and Classifications

OpenAIRE

Erwin Fielt

2013-01-01

The business model concept is gaining traction in different disciplines but is still criticized for being fuzzy and vague and lacking consensus on its definition and compositional elements. In this paper we set out to advance our understanding of the business model concept by addressing three areas of foundational research: business model definitions, business model elements, and business model archetypes. We define a business model as a representation of the value logic of an organization in...

Pattern Recognition-Based Analysis of COPD in CT

DEFF Research Database (Denmark)

Sørensen, Lauge Emil Borch Laurs

recognition part is used to turn the texture measures, measured in a CT image of the lungs, into a quantitative measure of disease. This is done by applying a classifier that is trained on a training set of data examples with known lung tissue patterns. Different classification systems are considered, and we...... will in particular use the pattern recognition concepts of supervised learning, multiple instance learning, and dissimilarity representation-based classification. The proposed texture-based measures are applied to CT data from two different sources, one comprising low dose CT slices from subjects with manually...... annotated regions of emphysema and healthy tissue, and one comprising volumetric low dose CT images from subjects that are either healthy or suffer from COPD. Several experiments demonstrate that it is clearly beneficial to take the lung tissue texture into account when classifying or quantifying emphysema...

PROGNOSTICAL COMPETENCE OF THE FUTURE TEACHERS-ACTORS: TO THE ISSUE OF THE CONCEPT DEFINITION

Directory of Open Access Journals (Sweden)

Elena Viktorovna Tsalko

2016-02-01

Full Text Available In this paper on the basis of the notions of competence, forecasting, prognostical competence the author’s definition of future actors-teachers’ prognostical competence is developed. Under prognostic competence of future actors-teachers we understand a special competence that allows the subject, engaged in professional activities as a performer of roles in the theater (movies, TV, as well as performing teaching activities in the field of arts, to receive the necessary anticipatory information about the phenomenon under investigation (on performing roles in the theatre, films, and television, on the learning process and actors-teachers training. Components of prognostical competence as a type of competencies (cognitive, instrumental and operational and motivational-value are singled out. The feature of the future actor-teacher’s professional activities in the context of prognostical competence is viewed. It is the simultaneous solving the artistic-creative, organizational and teaching-upbringing problems.Purpose. The purpose of the paper is the definition of prognostical competence of future teachers-actors.Methodology. In the research the methods of theoretical level are used: comparison, analysis and synthesis, generalization, concretization; analytical methods; idealization and modeling.Result. The result of the research is the development of the author’s concept of «prognostical competence of the future teachers-actors».Practical implications. Application of the results: The results may be applied to the work of teachers-actors’ trainers as well as the researchers in Pedagogy.

Social Accountable Medical Education: A concept analysis

Science.gov (United States)

ABDOLMALEKI, MOHAMMADREZA; YAZDANI, SHAHRAM; MOMENI, SEDIGHEH; MOMTAZMANESH, NADER

2017-01-01

Introduction: Considering the pervasiveness of social accountable medical education concept around the world and the growing trend of literature in this regard as well as various interpretations made about this concept, we found it necessary to analyze the concept of social accountable medical education. Methods: In this study, the modified version of McKenna’s approach to concept analysis was used to determine the concept, explain structures and substructures and determine the border concepts neighboring and against social accountability in medical education. Results: By studying the selected sources,the components of the concept were obtained to identify it and express an analytic definition of social accountability in medical education system. Then, a model case with all attributes of the given concept and the contrary and related concepts were mentioned to determine the boundary between the main concept and auxiliary ones. Conclusion: According to the results of this study in the field of social accountability, the detailed and transparent analytical definition of social accountable medical education can be used in future studies as well as the function and evaluation of medical education system. PMID:28761884

PET/CT in patients with hepatocellular carcinoma using [{sup 18}F]fluorocholine: preliminary comparison with [{sup 18}F]FDG PET/CT

Energy Technology Data Exchange (ETDEWEB)

Talbot, Jean-Noel; Gutman, Fabrice; Kerrou, Khaldoun; Grahek, Dany; Montravers, Francoise [Hopital Tenon, AP-HP, et Universite Pierre et Marie Curie, Department of Nuclear Medicine, Paris (France); Fartoux, Laetitia; Poupon, Raoul; Rosmorduc, Olivier [Hopital Saint-Antoine, AP-HP, et Universite Pierre et Marie Curie, Department of Hepatology, Paris (France); Grange, Jean-Didier [Hopital Tenon, AP-HP, et Universite Pierre et Marie Curie, Department of Hepatology, Paris (France); Ganne, Nathalie [Hopital Jean Verdier, AP-HP, Department of Hepatology, Bondy (France)

2006-11-15

The diagnostic accuracy of [{sup 18}F]fluorodeoxyglucose (FDG) PET is insufficient to characterise hepatocellular carcinoma (HCC) in liver masses and to diagnose all cases of recurrent HCC. HCC has been reported to take up [{sup 11}C]acetate, but routine use of this tracer is difficult. Choline is another tracer of lipid metabolism, present in large amounts in HCC. In a proof-of-concept study, we evaluated [{sup 18}F]fluorocholine (FCH) uptake by HCC and compared FCH PET/CT with FDG PET/CT. Twelve patients with newly diagnosed (n=8) or recurrent HCC (n=4) were prospectively enrolled. HCC was assessed by histology in eight cases and by American Association for the Study of Liver Diseases (AASLD) criteria in four cases. All patients underwent whole-body PET/CT 10 min after injection of 4 MBq/kg FCH. Within 1 week, 9 of the 12 patients also underwent whole-body FDG PET/CT 1 h after injection of 5 MBq/kg FDG. The per-patient analysis showed a detection rate of 12/12 using FCH PET/CT for both newly diagnosed and recurrent HCC. The median signal to noise ratio was 1.5{+-}0.38. There was a trend towards a higher FCH SUV{sub max} in well-differentiated HCC (15.6{+-}7.9 vs 11.9{+-}0.9, NS). Of the nine patients who underwent FCH and FDG PET/CT, all nine were positive with FCH whereas only five were positive with FDG. FCH provides a high detection rate for HCC, making it potentially useful in the initial evaluation of HCC or in the detection of recurrent disease. The favourable result of this proof-of-concept study opens the way to a phase III prospective study. (orig.)

Structural Measures to Track the Evolution of SNOMED CT Hierarchies

Science.gov (United States)

Wei, Duo; Gu, Huanying (Helen); Perl, Yehoshua; Halper, Michael; Ochs, Christopher; Elhanan, Gai; Chen, Yan

2015-01-01

The Systematized Nomenclature of Medicine Clinical Terms (SNOMED CT) is an extensive reference terminology with an attendant amount of complexity. It has been updated continuously and revisions have been released semi-annually to meet users’ needs and to reflect the results of quality assurance (QA) activities. Two measures based on structural features are proposed to track the effects of both natural terminology growth and QA activities based on aspects of the complexity of SNOMED CT. These two measures, called the structural density measure and accumulated structural measure, are derived based on two abstraction networks, the area taxonomy and the partial-area taxonomy. The measures derive from attribute relationship distributions and various concept groupings that are associated with the abstraction networks. They are used to track the trends in the complexity of structures as SNOMED CT changes over time. The measures were calculated for consecutive releases of five SNOMED CT hierarchies, including the Specimen hierarchy. The structural density measure shows that natural growth tends to move a hierarchy’s structure toward a more complex state, whereas the accumulated structural measure shows that QA processes tend to move a hierarchy’s structure toward a less complex state. It is also observed that both the structural density and accumulated structural measures are useful tools to track the evolution of an entire SNOMED CT hierarchy and reveal internal concept migration within it. PMID:26260003

The role of CT in patient management after liver transplantation

International Nuclear Information System (INIS)

Galanski, M.; Drewes, J.; Gubernatis, G.; Chavan, A.; Prokop, M.

1992-01-01

To evaluate the value of CT in clarifying the nature of complications after orthopedic liver transplantation, we restrospectively evaluated the files of 88 patients in light of the clinical course and all available diagnostic data. The liver tranplantations were performed in the years 1986 and 1987. As a rule, the examinations comprised of continuous 8 mm-thick CT sections of the abdomen. In the majority of the cases, contrast medium was administered for opacification of the bowel loops, either orally or through a tube. Bowel movement was reduced by intravenous (i.v.) Buscopan. In our series an increase in the periportal hypodensities was found to be an unfavourable prognostic sign. A high percentage of patients with this CT finding subsequently progressed to graft failure due to reasons other than graft rejection. Hence in the final analysis, the CT sign is non-specific and does not permit the definitive diagnosis of graft rejection. Nevertheless, CT is important for excluding conditions that demand surgical intervention, in particular abscess formation. (orig./MG)

Usefulness of CT-guided automatic needle biopsy of solitary pulmonary nodule smaller than 15 mm

International Nuclear Information System (INIS)

Jin, Gong Yong; Lim, Yeong Su

2004-01-01

To evaluate the usefulness of the CT-guided percutaneous lung biopsy for the solitary pulmonary nodules smaller than 15 mm in diameter. Between April 2002 and May 2003, we evaluated twenty-five patients (11 men, 14 women, mean ages: 52.5 years) who had solitary pulmonary nodules, which we could not discriminate as being benign or malignant on the CT findings. All the subjects had CT-guided percutaenous cutting needle biopsy (PCNB) performed on them at our institution. A definitive diagnosis of benignity or malignancy was established to retrospectively analyze the patient's records. We evaluated the accuracy, sensitivity, specificity and complications of PCNB for the definitive diagnosis of benignity or malignancy. The sensitivity and specificity of PCNB were determined using the Chi-square test, and the correlations with pneumothorax and emphysema after biopsy were analyzed using Spearman's rank correlation coefficient. In two nodules of the twenty-five nodules, no definitive diagnosis could be established. Of the remaining twenty-three nodules, 7 (30.4%) were malignant and 16 (69.6%) were benign. Twenty (87%) of the twenty-three definitively diagnosed nodules were correctly diagnosed with PCNB. Of the twenty nodules, 6 (30%) were malignant and 14 (70%) were benign. The sensitivity and specificity of the malignant nodules were 85.7% (6/7) and 100% (16/16), respectively. The sensitivity and specificity of the benign nodules were 87.5% (14/16) and 85.7% (6/7), respectively. Post-biopsy complication occurred in nine patients (36%): Hemoptysis (n=4, 16%) and pneumothorax (n=5, 20%). However, there was not a statistical significance between pneumothorax and emphysema after biopsy (r=0.3, p=0.15). When CT-guided percutaneous lung biopsy of the solitary pulmonary nodules smaller than 15 mm in diameter was performed without an on-site cytopathologist, we know that PCNB can yield high diagnostic accuracy and very few complications

Foix-Chavany syndrome. CT study and clinical report of three cases

Energy Technology Data Exchange (ETDEWEB)

Ferrari, G; Boninsegna, C [Santa Chiara Hospital, Trento (Italy). Div. of Neurology; Beltramello, A

1979-01-01

The Foix-Chavany syndrome is a neurological entity characterized by linguo-bucco-facial apraxia almost always caused by disturbed cerebral circulation. Three typical cases of this syndrome are described and the role of the CT scan to obtain a definite diagnosis is emphasized.

Analysis of a human phenomenon: self-concept.

Science.gov (United States)

LeMone, P

1991-01-01

This analysis of self-concept includes an examination of definitions, historical perspectives, theoretical basis, and closely related terms. Antecedents, consequences, defining attributes, and a definition were formulated based on the analysis. The purpose of the analysis was to provide support for the use of the label "self-concept" as a broad category that encompasses the self-esteem, identity, and body-image nursing diagnoses within Taxonomy I. This classification could allow the use of a broad diagnostic label to better describe conditions that necessitate nursing care. It may also further explain the relationships between and among those diagnoses that describe human responses to disturbance of any component of the self-concept.

Renewable energy for sustainable urban development: Redefining the concept of energisation

Energy Technology Data Exchange (ETDEWEB)

Nissing, Christian [Environmental and Process Systems Engineering Research Group, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town (South Africa); Blottnitz, Harro von, E-mail: Harro.vonBlottnitz@uct.ac.z [Environmental and Process Systems Engineering Research Group, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town (South Africa); African Centre for Cities, University of Cape Town (South Africa)

2010-05-15

It is widely recognised that access to and supply of modern energy play a key role in poverty alleviation and sustainable development. The emerging concept of energisation seems to capture this idea; however, there is no unified definition at the point of writing. In this paper, the aim is to propose a new and comprehensive definition of the concept of energisation. The chronological development of this concept is investigated by means of a literature review, and a subsequent critique is offered of current definitions and usage of the concept. Building upon these first insights, two planned cases of energisation in post-apartheid South Africa are contrasted to an unplanned one: they are the national electrification programme, the integrated energy centres initiative, and a wood fuelled local economy in Khayelitsha, Cape Town's biggest township. Especially the latter case, based on original data collection by the authors, provides a new understanding of specific elements affecting energisation. Finally, a new and detailed definition of the concept of sustainable energisation is developed by systematically reiterating three key elements: the target group, the concept of energy services, and sustainable development.

Renewable energy for sustainable urban development. Redefining the concept of energisation

Energy Technology Data Exchange (ETDEWEB)

Nissing, Christian [Environmental and Process Systems Engineering Research Group, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town (South Africa); Von Blottnitz, Harro [Environmental and Process Systems Engineering Research Group, Department of Chemical Engineering, University of Cape Town, Private Bag X3, Rondebosch 7701, Cape Town (South Africa); African Centre for Cities, University of Cape Town (South Africa)

2010-05-15

It is widely recognised that access to and supply of modern energy play a key role in poverty alleviation and sustainable development. The emerging concept of energisation seems to capture this idea; however, there is no unified definition at the point of writing. In this paper, the aim is to propose a new and comprehensive definition of the concept of energisation. The chronological development of this concept is investigated by means of a literature review, and a subsequent critique is offered of current definitions and usage of the concept. Building upon these first insights, two planned cases of energisation in post-apartheid South Africa are contrasted to an unplanned one: they are the national electrification programme, the integrated energy centres initiative, and a wood fuelled local economy in Khayelitsha, Cape Town's biggest township. Especially the latter case, based on original data collection by the authors, provides a new understanding of specific elements affecting energisation. Finally, a new and detailed definition of the concept of sustainable energisation is developed by systematically reiterating three key elements: the target group, the concept of energy services, and sustainable development. (author)

Renewable energy for sustainable urban development: Redefining the concept of energisation

International Nuclear Information System (INIS)

Nissing, Christian; Blottnitz, Harro von

2010-01-01

It is widely recognised that access to and supply of modern energy play a key role in poverty alleviation and sustainable development. The emerging concept of energisation seems to capture this idea; however, there is no unified definition at the point of writing. In this paper, the aim is to propose a new and comprehensive definition of the concept of energisation. The chronological development of this concept is investigated by means of a literature review, and a subsequent critique is offered of current definitions and usage of the concept. Building upon these first insights, two planned cases of energisation in post-apartheid South Africa are contrasted to an unplanned one: they are the national electrification programme, the integrated energy centres initiative, and a wood fuelled local economy in Khayelitsha, Cape Town's biggest township. Especially the latter case, based on original data collection by the authors, provides a new understanding of specific elements affecting energisation. Finally, a new and detailed definition of the concept of sustainable energisation is developed by systematically reiterating three key elements: the target group, the concept of energy services, and sustainable development.

A new method for measuring coronary artery diameters with CT spatial profile curves

International Nuclear Information System (INIS)

Shimamoto, Ryoichi; Suzuki, Jun-ichi; Yamazaki, Tadashi; Tsuji, Taeko; Ohmoto, Yuki; Morita, Toshihiro; Yamashita, Hiroshi; Honye, Junko; Nagai, Ryozo; Akahane, Masaaki; Ohtomo, Kuni

2007-01-01

Purpose: Coronary artery vascular edge recognition on computed tomography (CT) angiograms is influenced by window parameters. A noninvasive method for vascular edge recognition independent of window setting with use of multi-detector row CT was contrived and its feasibility and accuracy were estimated by intravascular ultrasound (IVUS). Methods: Multi-detector row CT was performed to obtain 29 CT spatial profile curves by setting a line cursor across short-axis coronary angiograms processed by multi-planar reconstruction. IVUS was also performed to determine the reference coronary diameter. IVUS diameter was fitted horizontally between two points on the upward and downward slopes of the profile curves and Hounsfield number was measured at the fitted level to test seven candidate indexes for definition of intravascular coronary diameter. The best index from the curves should show the best agreement with IVUS diameter. Results: Of the seven candidates the agreement was the best (agreement: 16 ± 11%) when the two ratios of Hounsfield number at the level of IVUS diameter over that at the peak on the profile curves were used with water and with fat as the background tissue. These edge definitions were achieved by cutting the horizontal distance by the curves at the level defined by the ratio of 0.41 for water background and 0.57 for fat background. Conclusions: Vascular edge recognition of the coronary artery with CT spatial profile curves was feasible and the contrived method could define the coronary diameter with reasonable agreement

Time-resolved CT angiography in aortic dissection

International Nuclear Information System (INIS)

Meinel, Felix G.; Nikolaou, Konstantin; Weidenhagen, Rolf; Hellbach, Katharina; Helck, Andreas; Bamberg, Fabian; Reiser, Maximilian F.; Sommer, Wieland H.

2012-01-01

Objectives: We performed this study to assess feasibility and additional diagnostic value of time-resolved CT angiography of the entire aorta in patients with aortic dissection. Materials and methods: 14 consecutive patients with known or suspected aortic dissection (aged 60 ± 9 years) referred for aortic CT angiography were scanned on a dual-source CT scanner (Somatom Definition Flash; Siemens, Forchheim, Germany) using a shuttle mode for multiphasic image acquisition (range 48 cm, time resolution 6 s, 6 phases, 100 kV, 110 mAs/rot). Effective radiation doses were calculated from recorded dose length products. For all phases, CT densities were measured in the aortic lumen and renal parenchyma. From the multiphasic data, 3 phases corresponding to a triphasic standard CT protocol, served as a reference and were compared against findings from the time-resolved datasets. Results: Mean effective radiation dose was 27.7 ± 3.5 mSv. CT density of the true lumen peaked at 355 ± 53 HU. Compared to the simulated triphasic protocol, time-resolved CT angiography added diagnostic information regarding a number of important findings: the enhancement delay between true and false lumen (n = 14); the degree of membrane oscillation (n = 14); the perfusion delay in arteries originating from the false lumen (n = 9). Other additional information included true lumen collapse (n = 4), quantitative assessment of renal perfusion asymmetry (n = 2), and dynamic occlusion of aortic branches (n = 2). In 3/14 patients (21%), these additional findings of the multiphasic protocol altered patient management. Conclusions: Multiphasic, time-resolved CT angiography covering the entire aorta is feasible at a reasonable effective radiation dose and adds significant diagnostic information with therapeutic consequences in patients with aortic dissection.

Metaphysical Concept of Secularization versus Islamic Concept of Secularization

Directory of Open Access Journals (Sweden)

Volkan ERTİT

2017-12-01

Full Text Available In early 21st century, the question “Is Turkey becoming secularized contrary to popular belief?” was one of the discussions occupying Turkish public opinion. These discussions led to the encounter of two different concepts of secularization, “theological (Islamic” and "metaphysical", and to put forward different claims using the same concept. Hence, it became evidentwas understood that a discussion was necessary to understand what secularization is and what it is not before starting any debate on Turkey's secularization. That is because the metaphysical discussion that defines secularization as the decline in the social influence of metaphysical realm (religion, religion-like mechanisms, folk religions, superstitious beliefs, etc. is overshadowed by the Islamic definition describing secularization as "irreligiousness" or "non-Islamism". Therefore, discussingTo understand the social transformation in Turkey, this article attempts to explain that metaphysical rather than theological definition of secularization is necessary for understanding the social implications of the process of modernization.

Green economy and related concepts

NARCIS (Netherlands)

Loiseau, Eleonore; Saikku, Laura; Antikainen, Riina; Droste, Nils; Hansjürgens, Bernd; Pitkänen, Kati; Leskinen, Pekka; Kuikman, Peter; Thomsen, Marianne

2016-01-01

For the last ten years, the notion of a green economy has become increasingly attractive to policy makers. However, green economy covers a lot of diverse concepts and its links with sustainability are not always clear. In this article, we focus on definitions of green economy and related concepts

Transboundary natural area protection: Broadening the definition of national security

Science.gov (United States)

Haven B. Cook

2007-01-01

This paper looks at the definition and concept of national security, and examines how the environment is linked with national security. The traditional, state view of national security that guides most foreign policy includes the concepts of military power, sovereignty and geopolitical stability. This paper advocates broadening the definition of security to include...

Patient doses in CT examinations in Switzerland: Implementation of national diagnostic reference levels

International Nuclear Information System (INIS)

Treier, R.; Aroua, A.; Verdun, F. R.; Samara, E.; Stuessi, A.; Trueb, P. R.

2010-01-01

Diagnostic reference levels (DRLs) were established for 21 indication-based CT examinations for adults in Switzerland. One hundred and seventy-nine of 225 computed tomography (CT) scanners operated in hospitals and private radiology institutes were audited on-site and patient doses were collected. For each CT scanner, a correction factor was calculated expressing the deviation of the measured weighted computed tomography dose index (CTDI) to the nominal weighted CTDI as displayed on the workstation. Patient doses were corrected by this factor providing a realistic basis for establishing national DRLs. Results showed large variations in doses between different radiology departments in Switzerland, especially for examinations of the petrous bone, pelvis, lower limbs and heart. This indicates that the concept of DRLs has not yet been correctly applied for CT examinations in clinical routine. A close collaboration of all stakeholders is mandatory to assure an effective radiation protection of patients. On-site audits will be intensified to further establish the concept of DRLs in Switzerland. (authors)

Extending Life Concepts to Complex Systems

Directory of Open Access Journals (Sweden)

Jean Le Fur

2013-01-01

Full Text Available There is still no consensus definition of complex systems. This article explores, as a heuristic approach, the possibility of using notions associated with life as transversal concepts for defining complex systems. This approach is developed within a general classification of systems, with complex systems considered as a general ‘living things’ category and living organisms as a specialised class within this category. Concepts associated with life are first explored in the context of complex systems: birth, death and lifetime, adaptation, ontogeny and growth, reproduction. Thereafter, a refutation approach is used to test the proposed classification against a set of diverse systems, including a reference case, edge cases and immaterial complex systems. The summary of this analysis is then used to generate a definition of complex systems, based on the proposal, and within the background of cybernetics, complex adaptive systems and biology. Using notions such as ‘birth’ or ‘lifespan’ as transversal concepts may be of heuristic value for the generic characterization of complex systems, opening up new lines of research for improving their definition.

Dose optimization in CT examination of children

International Nuclear Information System (INIS)

Hojreh, A.; Prosch, H.

2012-01-01

Problems arise due to the increased clinical use of computed tomography (CT) and the high radiosensitivity of children. The ALARA concept (as low as reasonably achievable) prevails in pediatric radiology. Justified indications and full utilization of available dose optimization methods. Medical physicists and the manufacturers should support pediatric radiology in the implementation of the ALARA concept. The referring physicians and radiology staff should be integrated into training programs. Sufficient diagnostic image quality is paramount and not the pretty images. (orig.) [de

Classifications, definitions and concepts of locality in Africa.

Science.gov (United States)

1983-01-01

Sub-Saharan Africa, one of the world's least urbanized regions, has within the last 30 years or so been experiencing a very high rate of urban population growth. The prevalence of small localities, invariably spread out over large land surfaces, complicates the classifications and definitions of localities as well as making the identification of settlement patterns in a mapping exercise and during a census or survey field operation difficult. The distinguishing features of a locality are: 1) a distinct (separate) population cluster, 2) inhabitants live in neighboring quarters, and 3) it has a name or a locally recognized status. Even in African countries, where the definition of locality as a distinct population cluster has been employed, problems have cropped up with respect to classifications and identifications. Another problem with the classification of localities is related to the rapid changes that occur in rural settlement patterns. Despite the rapid growth of urban localities within the past few years in sub-Saharan Africa, the proportion of the population living in urban localities is still low. Whereas a locality is a distinct population cluster, with definable boundaries, the village as employed in some countries does not have clear cut boundaries. The definition of a locality as a distinct population cluster in which the inhabitants live in neighboring living quarters and which has a name or a locally recognized status is highly recommended. The UN proposal for the adoption of a classification scheme by size of locality needs to be examined by African countries. The urban/rural dichotomy is recommended for the classification of some tabulations from censuses and surveys--especially on the total population and population of major and minor civil divisions.

Calling to Nursing: Concept Analysis.

Science.gov (United States)

Emerson, Christie

The aims of this article are (a) to analyze the concept of a calling as it relates nursing and (b) to develop a definition of calling to nursing with the detail and clarity needed to guide reliable and valid research. The classic steps described by Walker and Avant are used for the analysis. Literature from several disciplines is reviewed including vocational psychology, Christian career counseling, sociology, organizational management, and nursing. The analysis provides an operational definition of a calling to nursing and establishes 3 defining attributes of the concept: (a) a passionate intrinsic motivation or desire (perhaps with a religious component), (b) an aspiration to engage in nursing practice, as a means of fulfilling one's purpose in life, and (c) the desire to help others as one's purpose in life. Antecedents to the concept are personal introspection and cognitive awareness. Positive consequences to the concept are improved work meaningfulness, work engagement, career commitment, personal well-being, and satisfaction. Negative consequences of having a calling might include willingness to sacrifice well-being for work and problems with work-life balance. Following the concept analysis, philosophical assumptions, contextual factors, interdisciplinary work, research opportunities, and practice implications are discussed.

The personal knowledge base conception of information literacy

NARCIS (Netherlands)

A.A.J. (Jos) van Helvoort

2014-01-01

Although most authors on Information Literacy do not really differ in their definitions of the information literacy concept, phenomenographic research makes clear that in the context of education at least two different conceptions can be distinguished: an “Information Problem Solving” conception and

MR vs CT imaging: low rectal cancer tumour delineation for three-dimensional conformal radiotherapy.

LENUS (Irish Health Repository)

O'Neill, B D P

2009-06-01

Modern three-dimentional radiotherapy is based upon CT. For rectal cancer, this relies upon target definition on CT, which is not the optimal imaging modality. The major limitation of CT is its low inherent contrast resolution. Targets defined by MRI could facilitate smaller, more accurate, tumour volumes than CT. Our study reviewed imaging and planning data for 10 patients with locally advanced low rectal cancer (defined as < 6 cm from the anal verge on digital examination). Tumour volume and location were compared for sagittal pre-treatment MRI and planning CT. CT consistently overestimated all tumour radiological parameters. Estimates of tumour volume, tumour length and height of proximal tumour from the anal verge were larger on planning CT than on MRI (p < 0.05). Tumour volumes defined on MRI are smaller, shorter and more distal from the anal sphincter than CT-based volumes. For radiotherapy planning, this may result in smaller treatment volumes, which could lead to a reduction in dose to organs at risk and facilitate dose escalation.

Estimation and comparison of effective dose (E) in standard chest CT by organ dose measurements and dose-length-product methods and assessment of the influence of CT tube potential (energy dependency) on effective dose in a dual-source CT

International Nuclear Information System (INIS)

Paul, Jijo; Banckwitz, Rosemarie; Krauss, Bernhard; Vogl, Thomas J.; Maentele, Werner; Bauer, Ralf W.

2012-01-01

Highlights: ► The dual-energy protocol delivers the lowest effective dose of the investigated protocols for standard chest CT examinations, thus enabling functional imaging (like dual-energy perfusion) and can produce weighted images without dose penalty. ► The high-pitch protocol goes along with a 16% increase in dose compared to the standard 120 kV protocol and thus should preferably be used in pediatric, acute care settings (e.g. pulmonary embolism, aortic dissection and the like) or restless patients. ► The difference in effective dose estimates between ICRP 60 and 103 is minimal. ► Tube potential definitely has an effect on estimates of effective dose. - Abstract: Purpose: To determine effective dose (E) during standard chest CT using an organ dose-based and a dose-length-product-based (DLP) approach for four different scan protocols including high-pitch and dual-energy in a dual-source CT scanner of the second generation. Materials and methods: Organ doses were measured with thermo luminescence dosimeters (TLD) in an anthropomorphic male adult phantom. Further, DLP-based dose estimates were performed by using the standard 0.014 mSv/mGycm conversion coefficient k. Examinations were performed on a dual-source CT system (Somatom Definition Flash, Siemens). Four scan protocols were investigated: (1) single-source 120 kV, (2) single-source 100 kV, (3) high-pitch 120 kV, and (4) dual-energy with 100/Sn140 kV with equivalent CTDIvol and no automated tube current modulation. E was then determined following recommendations of ICRP publication 103 and 60 and specific k values were derived. Results: DLP-based estimates differed by 4.5–16.56% and 5.2–15.8% relatively to ICRP 60 and 103, respectively. The derived k factors calculated from TLD measurements were 0.0148, 0.015, 0.0166, and 0.0148 for protocol 1, 2, 3 and 4, respectively. Effective dose estimations by ICRP 103 and 60 for single-energy and dual-energy protocols show a difference of less than 0.04 m

Motivation: Approaching an Elusive Concept through the Factors That Shape It

Science.gov (United States)

Jang, Bong Gee; Conradi, Kristin; McKenna, Michael C.; Jones, Jill S.

2015-01-01

The main purpose of this article is to provide educators with clear definitions of motivational factors in reading so that instructional planning can capitalize on important distinctions. The authors present definitions of a small set of related motivational concepts (including attitudes, interests, self-efficacy, self-concept, goals, and value)…

An evolutionary concept analysis of futility in health care.

Science.gov (United States)

Morata, Lauren

2018-06-01

To report a concept analysis of futility in health care. Each member of the healthcare team: the physician, the nurse, the patient, the family and all others involved perceive futility differently. The current evidence and knowledge in regard to futility in health care manifest a plethora of definitions, meanings and interpretations without consensus. Concept analysis. Databases searched included Medline, Cumulative Index of Nursing and Allied Health Literature, Academic Search Premier, Cochrane Database of Systematic Reviews and PsycINFO. Search terms included "futil*," "concept analysis," "concept," "inefficacious," "non-beneficial," "ineffective" and "fruitless" from 1935-2016 to ensure a historical perspective of the concept. A total of 106 articles were retained to develop the concept. Rogers' evolutionary concept analysis was used to evaluate the concept of futility from ancient medicine to the present. Seven antecedents (the patient/family autonomy, surrogate decision-making movement, the patient-family/physician relationship, physician authority, legislation and court rulings, catastrophic events and advancing medical technology) lead to four major attributes (quantitative, physiologic, qualitative, and disease-specific). Ultimately, futile care could lead to consequences such as litigation, advancing technology, increasing healthcare costs, rationing, moral distress and ethical dilemmas. Futility in health care demonstrates components of a cyclical process and a consensus definition is proposed. A framework is developed to clarify the concept and articulate relationships among attributes, antecedents and consequences. Further testing of the proposed definition and framework are needed. © 2018 John Wiley & Sons Ltd.

A Phase II Comparative Study of Gross Tumor Volume Definition With or Without PET/CT Fusion in Dosimetric Planning for Non–Small-Cell Lung Cancer (NSCLC): Primary Analysis of Radiation Therapy Oncology Group (RTOG) 0515

International Nuclear Information System (INIS)

Bradley, Jeffrey; Bae, Kyounghwa; Choi, Noah; Forster, Ken; Siegel, Barry A.; Brunetti, Jacqueline; Purdy, James; Faria, Sergio; Vu, Toni; Thorstad, Wade; Choy, Hak

2012-01-01

Background: Radiation Therapy Oncology Group (RTOG) 0515 is a Phase II prospective trial designed to quantify the impact of positron emission tomography (PET)/computed tomography (CT) compared with CT alone on radiation treatment plans (RTPs) and to determine the rate of elective nodal failure for PET/CT-derived volumes. Methods: Each enrolled patient underwent definitive radiation therapy for non–small-cell lung cancer (≥60 Gy) and had two RTP datasets generated: gross tumor volume (GTV) derived with CT alone and with PET/CT. Patients received treatment using the PET/CT-derived plan. The primary end point, the impact of PET/CT fusion on treatment plans was measured by differences of the following variables for each patient: GTV, number of involved nodes, nodal station, mean lung dose (MLD), volume of lung exceeding 20 Gy (V20), and mean esophageal dose (MED). Regional failure rate was a secondary end point. The nonparametric Wilcoxon matched-pairs signed-ranks test was used with Bonferroni adjustment for an overall significance level of 0.05. Results: RTOG 0515 accrued 52 patients, 47 of whom are evaluable. The follow-up time for all patients is 12.9 months (2.7–22.2). Tumor staging was as follows: II = 6%; IIIA = 40%; and IIIB = 54%. The GTV was statistically significantly smaller for PET/CT-derived volumes (98.7 vs. 86.2 mL; p < 0.0001). MLDs for PET/CT plans were slightly lower (19 vs. 17.8 Gy; p = 0.06). There was no significant difference in the number of involved nodes (2.1 vs. 2.4), V20 (32% vs. 30.8%), or MED (28.7 vs. 27.1 Gy). Nodal contours were altered by PET/CT for 51% of patients. One patient (2%) has developed an elective nodal failure. Conclusions: PET/CT-derived tumor volumes were smaller than those derived by CT alone. PET/CT changed nodal GTV contours in 51% of patients. The elective nodal failure rate for GTVs derived by PET/CT is quite low, supporting the RTOG standard of limiting the target volume to the primary tumor and involved nodes.

Comparative evaluation of CT-based and respiratory-gated PET/CT-based planning target volume (PTV) in the definition of radiation treatment planning in lung cancer: preliminary results

Energy Technology Data Exchange (ETDEWEB)

Guerra, Luca; Elisei, Federica [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); Meregalli, Sofia; Niespolo, Rita [San Gerardo Hospital, Radiotherapy, Monza (Italy); Zorz, Alessandra; De Ponti, Elena; Morzenti, Sabrina; Crespi, Andrea [San Gerardo Hospital, Medical Physics, Monza (Italy); Brenna, Sarah [University of Milan-Bicocca, School of Radiation Oncology, Monza (Italy); Gardani, Gianstefano [San Gerardo Hospital, Radiotherapy, Monza (Italy); University of Milan-Bicocca, Milan (Italy); Messa, Cristina [San Gerardo Hospital, Nuclear Medicine, Monza (Italy); University of Milan-Bicocca, Tecnomed Foundation, Milan (Italy); National Research Council, Institute for Bioimaging and Molecular Physiology, Milan (Italy)

2014-04-15

The aim of this study was to compare planning target volume (PTV) defined on respiratory-gated positron emission tomography (PET)/CT (RG-PET/CT) to PTV based on ungated free-breathing CT and to evaluate if RG-PET/CT can be useful to personalize PTV by tailoring the target volume to the lesion motion in lung cancer patients. Thirteen lung cancer patients (six men, mean age 70.0 years, 1 small cell lung cancer, 12 non-small cell lung cancer) who were candidates for radiation therapy were prospectively enrolled and submitted to RG-PET/CT. Ungated free-breathing CT images obtained during a PET/CT study were visually contoured by the radiation oncologist to define standard clinical target volumes (CTV1). Standard PTV (PTV1) resulted from CTV1 with the addition of 1-cm expansion of margins in all directions. RG-PET/CT images were contoured by the nuclear medicine physician and radiation oncologist according to a standardized institutional protocol for contouring gated images. Each CT and PET image of the patient's respiratory cycle phases was contoured to obtain the RG-CT-based CTV (CTV2) and the RG-PET/CT-based CTV (CTV3), respectively. RG-CT-based and RG-PET/CT-based PTV (PTV2 and PTV3, respectively) were then derived from gated CTVs with a margin expansion of 7-8 mm in head to feet direction and 5 mm in anterior to posterior and left to right direction. The portions of gated PTV2 and PTV3 geometrically not encompassed in PTV1 (PTV2 out PTV1 and PTV3 out PTV1) were also calculated. Mean ± SD CTV1, CTV2 and CTV3 were 30.5 ± 33.2, 43.1 ± 43.2 and 44.8 ± 45.2 ml, respectively. CTV1 was significantly smaller than CTV2 and CTV3 (p = 0.017 and 0.009 with Student's t test, respectively). No significant difference was found between CTV2 and CTV3. Mean ± SD of PTV1, PTV2 and PTV3 were 118.7 ± 94.1, 93.8 ± 80.2 and 97.0 ± 83.9 ml, respectively. PTV1 was significantly larger than PTV2 and PTV3 (p = 0.038 and 0.043 with Student's t test, respectively). No

Investigation of virtual reality concept based on system analysis of conceptual series

Science.gov (United States)

Romanova, A.; Shuklin, D. A.; Kalinkina, M. E.; Gotskaya, I. B.; Ponomarev, Y. E.

2018-05-01

The paper covers approaches to the definition of virtual reality from the point of view of the humanitarian sciences and technology. Each approach analyzing problems of concept perception of methods interpreted by representatives of philosophy, psychology and sociology is singled out. Terminological analysis of the basic concepts is carried out and their refinement is constructed in the process of comparing the concepts of virtuality and virtual reality. Using the analysis of selected sources, a number of singularity characteristics of the given concept are singled out and its definition is specified. Results consist in combining the interpretation of all approaches to determine the concept of virtual reality. Due to the use of a comprehensive approach to the definition of the investigated concept, which allows us to consider the object of research as a set of elements that are subject to study with the help of a corresponding set of methods, one can conclude that the concept under study is complex and multifaceted. The authors noted that virtual reality technologies have a flexible concept depending on the field of application.

Comparing definitions in guidelines and written standards - a case study: 'Trueness'

International Nuclear Information System (INIS)

Pavese, F

2010-01-01

This paper describes the structure of a repository initiated by IMEKO TC21 to allow the comparison of different definitions and use of the same term or concept in written standards and guidelines available internationally. The method used is illustrated for a case study: the critical concept of 'trueness' and its definitions.

Reappraising the concept of massive transfusion in trauma

DEFF Research Database (Denmark)

Stanworth, Simon J; Morris, Timothy P; Gaarder, Christine

2010-01-01

ABSTRACT : INTRODUCTION : The massive-transfusion concept was introduced to recognize the dilutional complications resulting from large volumes of packed red blood cells (PRBCs). Definitions of massive transfusion vary and lack supporting clinical evidence. Damage-control resuscitation regimens...... of modern trauma care are targeted to the early correction of acute traumatic coagulopathy. The aim of this study was to identify a clinically relevant definition of trauma massive transfusion based on clinical outcomes. We also examined whether the concept was useful in that early prediction of massive...... transfusion as a concept in trauma has limited utility, and emphasis should be placed on identifying patients with massive hemorrhage and acute traumatic coagulopathy....

Space Mission Concept Development Using Concept Maturity Levels

Science.gov (United States)

Wessen, Randii R.; Borden, Chester; Ziemer, John; Kwok, Johnny

2013-01-01

Over the past five years, pre-project formulation experts at the Jet Propulsion Laboratory (JPL) has developed and implemented a method for measuring and communicating the maturity of space mission concepts. Mission concept development teams use this method, and associated tools, prior to concepts entering their Formulation Phases (Phase A/B). The organizing structure is Concept Maturity Level (CML), which is a classification system for characterizing the various levels of a concept's maturity. The key strength of CMLs is the ability to evolve mission concepts guided by an incremental set of assessment needs. The CML definitions have been expanded into a matrix form to identify the breadth and depth of analysis needed for a concept to reach a specific level of maturity. This matrix enables improved assessment and communication by addressing the fundamental dimensions (e.g., science objectives, mission design, technical risk, project organization, cost, export compliance, etc.) associated with mission concept evolution. JPL's collaborative engineering, dedicated concept development, and proposal teams all use these and other CML-appropriate design tools to advance their mission concept designs. This paper focuses on mission concept's early Pre-Phase A represented by CMLs 1- 4. The scope was limited due to the fact that CMLs 5 and 6 are already well defined based on the requirements documented in specific Announcement of Opportunities (AO) and Concept Study Report (CSR) guidelines, respectively, for competitive missions; and by NASA's Procedural Requirements NPR 7120.5E document for Projects in their Formulation Phase.

Corporate entrepreneurship - Distilling the concept

Directory of Open Access Journals (Sweden)

Colene Hind

2015-07-01

Full Text Available Background: Corporate entrepreneurship (CE is credited for many positive organisational outcomes, including systemic growth and increased revenue. Several terms associated with CE, including strategic renewal, corporate venturing and intrapreneurship are frequently used interchangeably and often confuse scholars, researchers and practitioners. The lack of clarity about the exact meaning of these terms is detrimental to the synergy in the current body of knowledge and the development of models involving these concepts. Objective: The aim of this paper was to describe CE as a unique concept, distinguishable from related concepts. Methodology: Several definitions of CE as well as the related terms were dissected, to identify core elements associated with each of them. The validity of these comprehensive definitions was tested by requesting 68 master’s degree students to classify the definitions. Inter-rater reliabilities were calculated in order to assess the level of agreement in the classification of the constructs. Results: The results indicate that CE is difficult to distinguish from strategic renewal and corporate venturing, but that intrapreneurship seems to be better defined and separate from the other constructs. Conclusion: These results emphasise the conceptual confusion that exists around CE and the need for further clarification of terminology. KEY WORDS Corporate entrepreneurship, strategic renewal, corporate venturing, intrapreneurship.

Acute kidney injury: definition, diagnosis and epidemiology.

Science.gov (United States)

Rossaint, Jan; Zarbock, Alexander

2016-02-01

Acute kidney injury (AKI) is a common complication in hospitalized patients and great efforts by leading experts have been made in order to establish common definitions of AKI. The clinical use of these consensus definitions has led to a substantially improved understanding of AKI. In addition, the consensus definitions allow to compare AKI incidence and outcomes between different patient populations. As a result, it has become evident that AKI in the Western population represents a clinical syndrome with an incidence close to that of myocardial infarction. The aim of this review is to revisit the current concepts and definitions of AKI, to highlight its diagnosis, and to emphasize its epidemiological characteristics. Here, we will focus on the available literature reporting the epidemiology of AKI in critically ill patients. Sepsis, major surgery, and nephrotoxic drugs are the main causes of AKI in these patients, and its occurrence is associated with an increased risk for sustained chronic kidney injury. We also discuss the concept of renal angina as a possible future concept for improved clinical risk stratification to detect AKI. In this regard, we emphasize the importance of the use of novel biomarkers in the diagnosis of AKI, as they hold the potential to improve early diagnosis and prevention in the clinical setting.

ITER definition phase

International Nuclear Information System (INIS)

1989-01-01

The International Thermonuclear Experimental Reactor (ITER) is envisioned as a fusion device which would demonstrate the scientific and technological feasibility of fusion power. As a first step towards achieving this goal, the European Community, Japan, the Soviet Union, and the United States of America have entered into joint conceptual design activities under the auspices of the International Atomic Energy Agency. A brief summary of the Definition Phase of ITER activities is contained in this report. Included in this report are the background, objectives, organization, definition phase activities, and research and development plan of this endeavor in international scientific collaboration. A more extended technical summary is contained in the two-volume report, ''ITER Concept Definition,'' IAEA/ITER/DS/3. 2 figs, 2 tabs

18F-fluorodeoxyglucose PET and PET-CT in early detection of cancer recurrent

International Nuclear Information System (INIS)

Xing Yan; Zhao Jinhua

2007-01-01

Early detection of recurrent can improve prognosis and survival of patients with cancer. 18 F- fluorodeoxyglucose( 18 F-FDG) PET can detect metabolic changes before structural changes. The fused imaging provided by PET-CT can precisely localize the foci and demonstrate the complementary roles of functional and anatomic assessments in the diagnosis of cancer recurrence. In addition to the accurate diagnosis and definition of the whole extent of recurrent cancer, 18 F-FDG PET and PET-CT can impact patients management. (authors)

CT imaging of necrosive fasciitis; CT-Bildgebung der nekrotisierenden Fasziitis

Energy Technology Data Exchange (ETDEWEB)

Schulze, M.; Overkamp, D.; Joanoviciu, S.; Horger, M.

2008-07-15

NF is a rare but dramatic and often fatal infection of the fascii and adjoining soft tissues. Contrary to the Fournier's definition, it is most common in elderly people. Patients with immune problems have a higher risk (e.g. Diabetes mellitus, alcohol or drug abuse, AIDS, leukaemia, chemotherapy and immunosuppressive medication). Predisposition factors are diverticulitis, insect bites, or surgical interventions (Uppot RN, Levy HM, PLatel PH, Radiology 2003; 226; 115; Wysoki MG, Santora TA, Shah RM et al. Necrotizing fasciitis: CT characteristics, Radiology 1997; 203;859). Men are affected more frequently than women. In principle, NF may occur everywhere in the body but incidence in the region of the scrotum, perineum and lower extremities are the most common. (orig.)

Pacing: a concept analysis of the chronic pain intervention.

Science.gov (United States)

Jamieson-Lega, Kathryn; Berry, Robyn; Brown, Cary A

2013-01-01

The intervention of pacing is regularly recommended for chronic pain patients. However, pacing is poorly defined and appears to be interpreted in varying, potentially contradictory manners within the field of chronic pain. This conceptual lack of clarity has implications for effective service delivery and for researchers' ability to conduct rigorous study. An examination of the background literature demonstrates that while pacing is often one part of a multidisciplinary pain management program, outcome research is hindered by a lack of a clear and shared definition of this currently ill-defined construct. To conduct a formal concept analysis of the term 'pacing'. A standardized concept analysis process (including literature scoping to identify all uses of the concept, analysis to determine defining attributes of the concept and identification of model, borderline and contrary cases) was used to determine what the concept of pacing does and does not represent within the current evidence base. A conceptual model including the core attributes of action, time, balance, learning and self-management emerged. From these attributes, an evidence-based definition for pacing was composed and distributed to stakeholders for review. After consideration of stakeholder feedback, the emergent definition of pacing was finalized as follows: "Pacing is an active self-management strategy whereby individuals learn to balance time spent on activity and rest for the purpose of achieving increased function and participation in meaningful activities". The findings of the present concept analysis will help to standardize the use and definition of the term pacing across disciplines for the purposes of both pain management and research.

Self-determination and older people--a concept analysis.

Science.gov (United States)

Ekelund, Christina; Dahlin-Ivanoff, Synneve; Eklund, Kajsa

2014-03-01

Self-determination has emerged as an important concept within health care, used to emphasize clients' control and independence as they participate in rehabilitation. To strengthen clients' self-determination is a central aim in occupational therapy. However, there is a lack of a clear definition of self-determination concerning community-dwelling older people. The definition should be flexible in different contexts, such as cultural. To define and clarify the concept of self-determination in relation to community-dwelling frail older people. Walker & Avant's analysis procedure was carried out to identify textual attributes to the concept of self-determination, supplemented by a content analysis of 21 articles that were used to define and further justify the textual attributes. Self-determination was used in diverse contexts for community-dwelling older people, concerning: decision-making in everyday life, professionals' views, health, and legal/ethical rights. Different textual attributes were identified, to propose a conceptual definition of self-determination in relation to community-dwelling frail older people: A process in which a person has control and legal/ethical rights, and has the knowledge and ability to make a decision of his/her own free choice. This concept analysis has contributed to clarifying the concept for the convenience of research with community-dwelling frail older people.

Concept Analysis of Spirituality: An Evolutionary Approach.

Science.gov (United States)

Weathers, Elizabeth; McCarthy, Geraldine; Coffey, Alice

2016-04-01

The aim of this article is to clarify the concept of spirituality for future nursing research. Previous concept analyses of spirituality have mostly reviewed the conceptual literature with little consideration of the empirical literature. The literature reviewed in prior concept analyses extends from 1972 to 2005, with no analysis conducted in the past 9 years. Rodgers' evolutionary framework was used to review both the theoretical and empirical literature pertaining to spirituality. Evolutionary concept analysis is a formal method of philosophical inquiry, in which papers are analyzed to identify attributes, antecedents, and consequences of the concept. Empirical and conceptual literature. Three defining attributes of spirituality were identified: connectedness, transcendence, and meaning in life. A conceptual definition of spirituality was proposed based on the findings. Also, four antecedents and five primary consequences of spirituality were identified. Spirituality is a complex concept. This concept analysis adds some clarification by proposing a definition of spirituality that is underpinned by both conceptual and empirical research. Furthermore, exemplars of spirituality, based on prior qualitative research, are presented to support the findings. Hence, the findings of this analysis could guide future nursing research on spirituality. © 2015 Wiley Periodicals, Inc.

Grounding abstractness: Abstract concepts and the activation of the mouth

Directory of Open Access Journals (Sweden)

Anna M Borghi

2016-10-01

Full Text Available One key issue for theories of cognition is how abstract concepts, such as freedom, are represented. According to the WAT (Words As social Tools proposal, abstract concepts activate both sensorimotor and linguistic/social information, and their acquisition modality involves the linguistic experience more than the acquisition of concrete concepts. We report an experiment in which participants were presented with abstract and concrete definitions followed by concrete and abstract target-words. When the definition and the word matched, participants were required to press a key, either with the hand or with the mouth. Response times and accuracy were recorded. As predicted, we found that abstract definitions and abstract words yielded slower responses and more errors compared to concrete definitions and concrete words. More crucially, there was an interaction between the target-words and the effector used to respond (hand, mouth. While responses with the mouth were overall slower, the advantage of the hand over the mouth responses was more marked with concrete than with abstract concepts. The results are in keeping with grounded and embodied theories of cognition and support the WAT proposal, according to which abstract concepts evoke linguistic-social information, hence activate the mouth. The mechanisms underlying the mouth activation with abstract concepts (re-enactment of acquisition experience, or re-explanation of the word meaning, possibly through inner talk are discussed. To our knowledge this is the first behavioral study demonstrating with real words that the advantage of the hand over the mouth is more marked with concrete than with abstract concepts, likely because of the activation of linguistic information with abstract concepts.

To the question of the definition of «lawyer»

Directory of Open Access Journals (Sweden)

Віктор Вікторович Заборовский

2016-04-01

Full Text Available The article is devoted to the problem with the definition of the concept of «lawyer». The aim is to identify the most complete understanding of the definition of the concept of «lawyer», which will continue to contribute to the proper study of the features status of the lawyer. The author used the formal-legal method on the basis of systematic and integrated its holding. The article makes a critical analysis of both scientific and legislatively fixed (including the European Union approaches to the definition of «lawyer». The conclusion is that the most common in the legal literature is a point of view that the disclosure of the definition of the concept of «lawyer» is done by the disclosure of professional (functional the appointment of such a person for protection, representation, or in general - to provide legal assistance to other parties. Specify on the feasibility of using a dual legal basis for the formation of the definition of the concept of «lawyer», according to which it consists of two parts, namely, the status and the functional side. The article questioned the feasibility of the existence of this definition, the fixed provisions of the legislation on the legal profession, and offers the author's definition of the term «lawyer» - a natural person who, in the manner prescribed by law has received status of the lawyer, and the right, in accordance with this status, to carry out lawyer for the protection, representation and provision of other types of legal assistance to the client.

Pitch and timbre : definition, meaning and use

NARCIS (Netherlands)

Houtsma, A.J.M.

1997-01-01

Pitch and timbre are terms frequently used in studies on sound perception. Despite the existence of formal definitions, these terms are often used ambiguously in the literature. This paper is intended as a review of the ANSI definitions and their shortcomings, of modern ways to define the concepts

CT examination of segmental liver transplants from living donors. Anatomy and pathological findings

International Nuclear Information System (INIS)

Krupski, G.; Maas, R.; Rogiers, X.; Burdelski, M.; Broelsch, C.E.

1994-01-01

A lack of suitable pediatric donors and significantly better results than conventional transplantation have contributed to the steady increase in the number of segmental liver transplants from living donors throughout the world. This article describes the diagnostic impact of axial CT scans following transplantation in a retrospective evaluation of 18 CT examinations of 10 children with an average age of two years. Both spiral and conventional CT scans permit precise visualization of the postoperative anatomy of the upper abdomen that is more distinct than the images provided by ultrasonic scans. Thus, CT scans better facilitate detection of pathological findings. In 60% of the patients (67% of the examinations), the CT scan permitted a definite diagnosis; in the remaining cases, no morphological correlate to the clinical and laboratory findings was detected. In addition to traditional ultrasonic scanning, computed tomography represents a further noninvasive imaging technique for postoperative diagnostics following segmental liver transplants from living donors. (orig.) [de

PET CT Thresholds for Radiotherapy Target Definition in Non-Small-Cell Lung Cancer: How Close are we to the Pathologic Findings?

International Nuclear Information System (INIS)

Wu Kailiang; Ung, Yee C.; Hornby, Jennifer

2010-01-01

Purpose: Optimal target delineation threshold values for positron emission tomography (PET) and computed tomography (CT) radiotherapy planning is controversial. In this present study, different PET CT threshold values were used for target delineation and then compared pathologically. Methods and Materials: A total of 31 non-small-cell lung cancer patients underwent PET CT before surgery. The maximal diameter (MD) of the pathologic primary tumor was obtained. The CT-based gross tumor volumes (GTV CT ) were delineated for CT window-level thresholds at 1,600 and -300 Hounsfield units (HU) (GTV CT1 ); 1,600 and -400 (GTV CT2 ); 1,600 and -450 HU (GTV CT3 ); 1,600 and -600 HU (GTV CT4 ); 1,200 and -700 HU (GTV CT5 ); 900 and -450 HU (GTV CT6 ); and 700 and -450 HU (GTV CT7 ). The PET-based GTVs (GTV PET ) were autocontoured at 20% (GTV 20 ), 30% (GTV 30 ), 40% (GTV 40 ), 45% (GTV 45 ), 50% (GTV 50 ), and 55% (GTV 55 ) of the maximal intensity level. The MD of each image-based GTV in three-dimensional orientation was determined. The MD of the GTV PET and GTV CT were compared with the pathologically determined MD. Results: The median MD of the GTV CT changed from 2.89 (GTV CT2 ) to 4.46 (GTV CT7 ) as the CT thresholds were varied. The correlation coefficient of the GTV CT compared with the pathologically determined MD ranged from 0.76 to 0.87. The correlation coefficient of the GTV CT1 was the best (r = 0.87). The median MD of GTV PET changed from 5.72cm to 2.67cm as the PET thresholds increased. The correlation coefficient of the GTV PET compared with the pathologic finding ranged from 0.51 to 0.77. The correlation coefficient of GTV 50 was the best (r = 0.77). Conclusion: Compared with the MD of GTV PET , the MD of GTV CT had better correlation with the pathologic MD. The GTV CT1 and GTV 50 had the best correlation with the pathologic results.

The CT diagnosis and differential diagnosis of malignant tumours of the paranasal sinuses

International Nuclear Information System (INIS)

Graber, H.R.; Zaunbauer, W.; Haertel, M.

1986-01-01

The CT appearances of malignant tumours of the paranasal sinuses are illustrated on the basis of 15 patients, and the differential diagnosis discussed. Malignant soft tissue tumours in the paranasal sinuses are characterised on CT by their non-homogeneous structure; they may destroy the bony margins of the sinus and infiltrate neighbouring regions in certain preferred directions, and they may enhance following the administration of contrast. Precise definition of the malignant tumour by CT permits their exact staging, may help to determine therapy and is valuable for serial observation. It remains to be seen, however, whether the improved radiological diagnosis results in improved prognosis of malignant tumours of the paranasal sinuses. (orig.) [de

Value of early follow-up CT in paediatric tuberculous meningitis

International Nuclear Information System (INIS)

Andronikou, Savvas; Wieselthaler, Nicky; Smith, Bruce; Douis, Hassan; Fieggen, A. Graham; Toorn, Ronald van; Wilmshurst, Jo

2005-01-01

The value of CT in the diagnosis of tuberculous meningitis (TBM) in children is well reported. Follow-up CT scanning for these patients is, however, not well described and, in particular, the value of early follow-up CT has not been addressed for children with TBM. To assess the value of early follow-up CT in children with TBM in identifying diagnostic, prognostic and therapeutically relevant features of TBM. A retrospective 4-year review of CT scans performed within 1 week and 1 month of initial CT in children with proven (CSF culture-positive) and probable TBM (CSF profile-positive but culture-negative) and comparison with initial CT for the diagnostic, prognostic and therapeutic CT features of TBM. The CT scans of 50 children were included (19 ''definite'' TBM; 31 ''probable'' TBM). Of these, 30 had CT scans performed within 1 week of the initial CT. On initial CT, 44 patients had basal enhancement. Only 24 patients had contrast medium-enhanced follow-up scans. Important findings include: 8 of 29 patients (who were not shunted) developed new hydrocephalus. New infarcts developed in 24 patients; 45% of those who did not have infarction initially developed new infarcts. Three of the six patients who did not show basal enhancement on initial scans developed this on the follow-up scans, while in seven patients with pre-existing basal enhancement this became more pronounced. Two patients developed hyperdensity in the cisterns on non-contrast medium scans. Eight patients developed a diagnostic triad of features. Three patients developed CT features of TBM where there was none on the initial scans. Early follow-up CT is useful in making a diagnosis of TBM by demonstrating features that were not present initially and by demonstrating more sensitive, obvious or additional features of TBM. In addition, follow-up CT is valuable as a prognostic indicator as it demonstrates additional infarcts which may have developed or become more visible since the initial study. Lastly

Value of early follow-up CT in paediatric tuberculous meningitis

Energy Technology Data Exchange (ETDEWEB)

Andronikou, Savvas [University of Cape Town, Department of Radiology, Cape Town (South Africa); Wieselthaler, Nicky; Smith, Bruce; Douis, Hassan [Red Cross Children' s Hospital, Department of Paediatric Radiology, School of Child and Adolescent Health, Cape Town (South Africa); Fieggen, A. Graham; Toorn, Ronald van; Wilmshurst, Jo [Red Cross Children' s Hospital, Department of Paediatric Radiology, School of Child and Adolescent Health, Cape Town (South Africa); Red Cross Children' s Hospital, Department of Neurosciences, School of Child and Adolescent Health, Cape Town (South Africa)

2005-11-01

The value of CT in the diagnosis of tuberculous meningitis (TBM) in children is well reported. Follow-up CT scanning for these patients is, however, not well described and, in particular, the value of early follow-up CT has not been addressed for children with TBM. To assess the value of early follow-up CT in children with TBM in identifying diagnostic, prognostic and therapeutically relevant features of TBM. A retrospective 4-year review of CT scans performed within 1 week and 1 month of initial CT in children with proven (CSF culture-positive) and probable TBM (CSF profile-positive but culture-negative) and comparison with initial CT for the diagnostic, prognostic and therapeutic CT features of TBM. The CT scans of 50 children were included (19 ''definite'' TBM; 31 ''probable'' TBM). Of these, 30 had CT scans performed within 1 week of the initial CT. On initial CT, 44 patients had basal enhancement. Only 24 patients had contrast medium-enhanced follow-up scans. Important findings include: 8 of 29 patients (who were not shunted) developed new hydrocephalus. New infarcts developed in 24 patients; 45% of those who did not have infarction initially developed new infarcts. Three of the six patients who did not show basal enhancement on initial scans developed this on the follow-up scans, while in seven patients with pre-existing basal enhancement this became more pronounced. Two patients developed hyperdensity in the cisterns on non-contrast medium scans. Eight patients developed a diagnostic triad of features. Three patients developed CT features of TBM where there was none on the initial scans. Early follow-up CT is useful in making a diagnosis of TBM by demonstrating features that were not present initially and by demonstrating more sensitive, obvious or additional features of TBM. In addition, follow-up CT is valuable as a prognostic indicator as it demonstrates additional infarcts which may have developed or become more

SU-F-T-252: An Investigation of Gamma Knife Frame Definition Error When Using a Pre-Planning Workflow

International Nuclear Information System (INIS)

Johnson, P

2016-01-01

Purpose: To determine causal factors related to high frame definition error when treating GK patients using a pre-planning workflow. Methods: 160 cases were retrospectively reviewed. All patients received treatment using a pre-planning workflow whereby stereotactic coordinates are determined from a CT scan acquired after framing using a fiducial box. The planning software automatically detects the fiducials and compares their location to expected values based on the rigid design of the fiducial system. Any difference is reported as mean and maximum frame definition error. The manufacturer recommends these values be less than 1.0 mm and 1.5 mm. In this study, frame definition error was analyzed in comparison with a variety of factors including which neurosurgeon/oncologist/physicist was involved with the procedure, number of post used during framing (3 or 4), type of lesion, and which CT scanner was utilized for acquisition. An analysis of variance (ANOVA) approach was used to statistically evaluate the data and determine causal factors related to instances of high frame definition error. Results: Two factors were identified as significant: number of post (p=0.0003) and CT scanner (p=0.0001). Further analysis showed that one of the four scanners was significantly different than the others. This diagnostic scanner was identified as an older model with localization lasers not tightly calibrated. The average value for maximum frame definition error using this scanner was 1.48 mm (4 posts) and 1.75 mm (3 posts). For the other scanners this value was 1.13 mm (4 posts) and 1.40 mm (3 posts). Conclusion: In utilizing a pre-planning workflow the choice of CT scanner matters. Any scanner utilized for GK should undergo routine QA at a level appropriate for radiation oncology. In terms of 3 vs 4 post, it is hypothesized that three posts provide less stability during CT acquisition. This will be tested in future work.

SU-F-T-252: An Investigation of Gamma Knife Frame Definition Error When Using a Pre-Planning Workflow

Energy Technology Data Exchange (ETDEWEB)

Johnson, P [University of Miami, Miami, FL (United States)

2016-06-15

Purpose: To determine causal factors related to high frame definition error when treating GK patients using a pre-planning workflow. Methods: 160 cases were retrospectively reviewed. All patients received treatment using a pre-planning workflow whereby stereotactic coordinates are determined from a CT scan acquired after framing using a fiducial box. The planning software automatically detects the fiducials and compares their location to expected values based on the rigid design of the fiducial system. Any difference is reported as mean and maximum frame definition error. The manufacturer recommends these values be less than 1.0 mm and 1.5 mm. In this study, frame definition error was analyzed in comparison with a variety of factors including which neurosurgeon/oncologist/physicist was involved with the procedure, number of post used during framing (3 or 4), type of lesion, and which CT scanner was utilized for acquisition. An analysis of variance (ANOVA) approach was used to statistically evaluate the data and determine causal factors related to instances of high frame definition error. Results: Two factors were identified as significant: number of post (p=0.0003) and CT scanner (p=0.0001). Further analysis showed that one of the four scanners was significantly different than the others. This diagnostic scanner was identified as an older model with localization lasers not tightly calibrated. The average value for maximum frame definition error using this scanner was 1.48 mm (4 posts) and 1.75 mm (3 posts). For the other scanners this value was 1.13 mm (4 posts) and 1.40 mm (3 posts). Conclusion: In utilizing a pre-planning workflow the choice of CT scanner matters. Any scanner utilized for GK should undergo routine QA at a level appropriate for radiation oncology. In terms of 3 vs 4 post, it is hypothesized that three posts provide less stability during CT acquisition. This will be tested in future work.

How unique is continuity of care? A review of continuity and related concepts.

Science.gov (United States)

Uijen, Annemarie A; Schers, Henk J; Schellevis, François G; van den Bosch, Wil J H M

2012-06-01

The concept of 'continuity of care' has changed over time and seems to be entangled with other care concepts, for example coordination and integration of care. These concepts may overlap, and differences between them often remain unclear. In order to clarify the confusion of tongues and to identify core values of these patient-centred concepts, we provide a historical overview of continuity of care and four related concepts: coordination of care, integration of care, patient-centred care and case management. We identified and reviewed articles including a definition of one of these concepts by performing an extensive literature search in PubMed. In addition, we checked the definition of these concepts in the Oxford English Dictionary. Definitions of continuity, coordination, integration, patient-centred care and case management vary over time. These concepts show both great entanglement and also demonstrate differences. Three major common themes could be identified within these concepts: personal relationship between patient and care provider, communication between providers and cooperation between providers. Most definitions of the concepts are formulated from the patient's perspective. The identified themes appear to be core elements of care to patients. Thus, it may be valuable to develop an instrument to measure these three common themes universally. In the patient-centred medical home, such an instrument might turn out to be an important quality measure, which will enable researchers and policy makers to compare care settings and practices and to evaluate new care interventions from the patient perspective.

Value of integrated PET/CT in clinical staging of patients with lung cancer

International Nuclear Information System (INIS)

Zhao Jun; Guan Yihui; Zuo Chuantao; Hua Fengchun; Lin Xiangtong

2004-01-01

Objectives: The purpose of this study was to evaluate the value of combined fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) in patients with lung cancer, and to compare the results of PET/CT with those of FDG PET and CT alone. Methods: Forty-two patients were studied in this group. 3D whole body images were acquired using Siemens Biograph Sensetionl6 PET/CT scanner. Attenuation corrected PET images, CT and fusion images were interpreted. Reports were compared for each patient including identified the number of lesions, their anatomical localization and certainty of diagnosis. Results: PET/CT increased the number of lesions reported as being definitely abnormal or normal (+22%). In 12 patients (28.6%), the PET/CT report positively impacted surgical management when compared to the PET report alone. 6 patients were correctly downstaged negating further treatment or imaging, 3 patient was upstaged to inoperable and in another 3 ones improved localization by PET/CT led to an altered surgical incision with decreased morbidity. Lesion-based evaluation showed sensitivity for regional lymph node involvement of 61% for CT alone, 88% for FDG PET alone, and 96% for integrated PET/CT imaging respectively. In addition, PET/CT could identify some benign disease, including lung tuberculosis, cyst of liver and kidney, calculus etc. Conclusion: PET/CT improves anatomical localization and increases the certainty in reporting abnormal and normal lesions. PET/CT imaging is superior to CT alone and has additional benefit over FDG PET alone, and is accurate in clinical staging for lung cancer. (authors)

SU-F-J-214: Dose Reduction by Spatially Optimized Image Quality Via Fluence Modulated Proton CT (FMpCT)

International Nuclear Information System (INIS)

De Angelis, L; Landry, G; Dedes, G; Parodi, K; Hansen, D; Rit, S; Belka, C

2016-01-01

Purpose: Proton CT (pCT) is a promising imaging modality for reducing range uncertainty in image-guided proton therapy. Range uncertainties partially originate from X-ray CT number conversion to stopping power ratio (SPR) and are limiting the exploitation of the full potential of proton therapy. In this study we explore the concept of spatially dependent fluence modulated proton CT (FMpCT), for achieving optimal image quality in a clinical region of interest (ROI), while reducing significantly the imaging dose to the patient. Methods: The study was based on simulated ideal pCT using pencil beam (PB) scanning. A set of 250 MeV protons PBs was used to create 360 projections of a cylindrical water phantom and a head and neck cancer patient. The tomographic images were reconstructed using a filtered backprojection (FBP) as well as an iterative algorithm (ITR). Different fluence modulation levels were investigated and their impact on the image was quantified in terms of SPR accuracy as well as noise within and outside selected ROIs, as a function of imaging dose. The unmodulated image served as reference. Results: Both FBP reconstruction and ITR without total variation (TV) yielded image quality in the ROIs similar to the reference images, for modulation down to 0.1 of the full proton fluence. The average dose was reduced by 75% for the water phantom and by 40% for the patient. FMpCT does not improve the noise for ITR with TV and modulation 0.1. Conclusion: This is the first work proposing and investigating FMpCT for producing optimal image quality for treatment planning and image guidance, while simultaneously reducing imaging dose. Future work will address spatial resolution effects and the impact of FMpCT on the quality of proton treatment plans for a prototype pCT scanner capable of list mode data acquisition. Acknowledgement: DFG-MAP DFG - Munich-Centre for Advanced Photonics (MAP)

SU-F-J-214: Dose Reduction by Spatially Optimized Image Quality Via Fluence Modulated Proton CT (FMpCT)

Energy Technology Data Exchange (ETDEWEB)

De Angelis, L; Landry, G; Dedes, G; Parodi, K [Ludwig-Maximilians-Universitaet Muenchen (LMU Munich), Garching b. Muenchen (Germany); Hansen, D [Aarhus University Hospital, Aarhus, Jutland (Denmark); Rit, S [University Lyon, Lyon, Auvergne-Rhone-Alpes (France); Belka, C [LMU Munich, Munich (Germany)

2016-06-15

Purpose: Proton CT (pCT) is a promising imaging modality for reducing range uncertainty in image-guided proton therapy. Range uncertainties partially originate from X-ray CT number conversion to stopping power ratio (SPR) and are limiting the exploitation of the full potential of proton therapy. In this study we explore the concept of spatially dependent fluence modulated proton CT (FMpCT), for achieving optimal image quality in a clinical region of interest (ROI), while reducing significantly the imaging dose to the patient. Methods: The study was based on simulated ideal pCT using pencil beam (PB) scanning. A set of 250 MeV protons PBs was used to create 360 projections of a cylindrical water phantom and a head and neck cancer patient. The tomographic images were reconstructed using a filtered backprojection (FBP) as well as an iterative algorithm (ITR). Different fluence modulation levels were investigated and their impact on the image was quantified in terms of SPR accuracy as well as noise within and outside selected ROIs, as a function of imaging dose. The unmodulated image served as reference. Results: Both FBP reconstruction and ITR without total variation (TV) yielded image quality in the ROIs similar to the reference images, for modulation down to 0.1 of the full proton fluence. The average dose was reduced by 75% for the water phantom and by 40% for the patient. FMpCT does not improve the noise for ITR with TV and modulation 0.1. Conclusion: This is the first work proposing and investigating FMpCT for producing optimal image quality for treatment planning and image guidance, while simultaneously reducing imaging dose. Future work will address spatial resolution effects and the impact of FMpCT on the quality of proton treatment plans for a prototype pCT scanner capable of list mode data acquisition. Acknowledgement: DFG-MAP DFG - Munich-Centre for Advanced Photonics (MAP)

Clinical Reasoning in Medicine: A Concept Analysis

Directory of Open Access Journals (Sweden)

Shahram Yazdani

2018-01-01

Full Text Available Background: Clinical reasoning plays an important role in the ability of physicians to make diagnoses and decisions. It is considered the physician’s most critical competence, but it is an ambiguous conceptin medicine that needs a clear analysis and definition. Our aim was to clarify the concept of clinical reasoning in medicine by identifying its components and to differentiate it from other similar concepts.It is necessary to have an operational definition of clinical reasoning, and its components must be precisely defined in order to design successful interventions and use it easily in future research.Methods: McKenna’s nine-step model was applied to facilitate the clarification of the concept of clinical reasoning. The literature for this concept analysis was retrieved from several databases, including Scopus, Elsevier, PubMed, ISI, ISC, Medline, and Google Scholar, for the years 1995– 2016 (until September 2016. An extensive search of the literature was conducted using the electronic database. Accordingly, 17 articles and one book were selected for the review. We applied McKenna’s method of concept analysis in studying clinical reasoning, so that definitional attributes, antecedents, and consequences of this concept were extracted.Results: Clinical reasoning has nine major attributes in medicine. These attributes include: (1 clinical reasoning as a cognitive process; (2 knowledge acquisition and application of different types of knowledge; (3 thinking as a part of the clinical reasoning process; (4 patient inputs; (5 contextdependent and domain-specific processes; (6 iterative and complex processes; (7 multi-modal cognitive processes; (8 professional principles; and (9 health system mandates. These attributes are influenced by the antecedents of workplace context, practice frames of reference, practice models of the practitioner, and clinical skills. The consequences of clinical reasoning are the metacognitive improvement of

Use of CT or MR dosimetry in high dose rate (HDR) brachytherapy for prostate cancer

International Nuclear Information System (INIS)

Liu, C.; Das, R.; See, A.; Duchesne, G.M.; Van Dyk, S.; Tai, K.H.

2003-01-01

Brachytherapy (BT) has, in recent years, become a well-utilised treatment option for prostate cancer. Tumour control probability relies on accurate dosimetry, which in turn relies on the accurate definition of the prostate gland. In external beam radiotherapy and BT, MRI has been shown to be a superior imaging modality when delineating the prostate gland especially at the apex. To date, data on MRI planning in prostate BT has focussed mainly on permanent interstitial implants. No data currently exists comparing MRI vs CT planning in HDR BT and its subsequent impact on prostate dosimetry. To determine the effects of MRI vs CT in HDR BT with respect to prostatic volumes and normal tissue doses, with the evaluations made using dose-volume histograms (DVH). Dosimetry parameters derived using CT and MRI (T2 weighted) scans of 11 patients who had received TRUS guided implants for HDR BT, were compared using the PlatoTM computer planning system. Treatment plans were generated on volumes marked by the same radiation oncologist for each patient. Comparison was made of the treatment plans (dosimetry) between: 1. CT generated plans; 2. CT generated plans assessed using MRI marked volumes and 3. MRI generated plans. We confirm the previously reported results that CT scans can overestimate prostatic volumes compared with MRI. Variations were noted in CT and MRI based plans that may allow improved sparing of the rectum and urethra when using MRI planning. The main disadvantages of using MRI scans are access to facilities as well as identifying a dummy source to adequately define the tips of our catheters. It is feasible to utilise MRI scans for HDR BT planning. The clearer definition of anatomical structures has added advantages when contouring the prostate

Concept analysis of nurses' happiness.

Science.gov (United States)

Ozkara San, Eda

2015-01-01

The purpose of this analysis is to examine and clarify the concept of nurses' happiness (NH), understand the different uses of the concept, explore the conditions that foster it, and consider the consequences of NH, including the phenomena that emerge as a result of NH occurrence. The author utilizes Walker and Avant's eight-stage concept analysis. Computer and manual searches were conducted of articles in the English language addressing NH from 1990 to present. EBSCO and PubMed are the electronic databases used to access literature for this paper. For both databases, the researcher has examined this new term by splitting the term nurses' happiness into its two root words, namely nurses and happiness. An inductive analysis of articles produced descriptive themes. Definitions of happiness and NH are analyzed. Antecedents, attributes, and consequences of NH are described. Model, borderline, contrary, and related cases for NH are also identified. This concept analysis helps in the understanding of the definition of NH, the attributes that contribute to the occurrence of NH in clinical practice, as well as the consequences of NH, and how it should be measured from a nursing perspective. Ozkara San. © 2014 Wiley Periodicals, Inc.

Self-Concept and Self-Esteem: A Cross-Cultural Perspective.

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Wood, Melinda

1991-01-01

Describes issues of self-concept and self-esteem that arise when people find themselves living in a cross-cultural environment. Discusses Western definition of self-concept and other self-concept models. Discusses self-esteem and integration and adjustment as it relates to bicultural persons. (ABL)

How Effective Is Example Generation for Learning Declarative Concepts?

Science.gov (United States)

Rawson, Katherine A.; Dunlosky, John

2016-01-01

Declarative concepts (i.e., key terms and corresponding definitions for abstract concepts) represent foundational knowledge that students learn in many content domains. Thus, investigating techniques to enhance concept learning is of critical importance. Various theoretical accounts support the expectation that example generation will serve this…

The concept of work ability.

Science.gov (United States)

Tengland, Per-Anders

2011-06-01

The concept of "work ability" is central for many sciences, especially for those related to working life and to rehabilitation. It is one of the important concepts in legislation regulating sickness insurance. How the concept is defined therefore has important normative implications. The concept is, however, often not sufficiently well defined. AIM AND METHOD The objective of this paper is to clarify, through conceptual analysis, what the concept can and should mean, and to propose a useful definition for scientific and practical work. RESULTS Several of the defining characteristics found in the literature are critically scrutinized and discussed, namely health, basic standard competence, occupational competence, occupational virtues, and motivation. These characteristics are related to the work tasks and the work environment. One conclusion is that we need two definitions of work ability, one for specific jobs that require special training or education, and one for jobs that most people can manage given a short period of practice. Having work ability, in the first sense, means having the occupational competence, the health required for the competence, and the occupational virtues that are required for managing the work tasks, assuming that the tasks are reasonable and that the work environment is acceptable. In the second sense, having work ability is having the health, the basic standard competence and the relevant occupational virtues required for managing some kind of job, assuming that the work tasks are reasonable and that the work environment is acceptable. CONCLUSION These definitions give us tools for understanding and discussing the complex, holistic and dynamic aspects of work ability, and they can lay the foundations for the creation of instruments for evaluating work ability, as well as help formulate strategies for rehabilitation.

CT and MR imaging in the evaluation of leptomeningeal metastases

International Nuclear Information System (INIS)

Xiao Jiahe; Wang Dayou; Deng Kaihong

1999-01-01

Objective: To study the manifestations of leptomeningeal metastases on CT and MR imaging, and evaluate the diagnostic significance of both modalities for this disease. Methods: Clinical and neuroradiological data of 21 cases with leptomeningeal metastases were retrospectively reviewed. In this series, 16 patients were studied by CT and 7 patients by MRI, 2 patients by both CT and MRI. Results: Abnormal enhancement of pia and subarachnoid space, appearing as diffuse pattern in 10 cases, nodular pattern in 8 cases and mixed pattern with diffuse plus nodules in 3 cases, were visualized by CE-CT and Gd-MRI. Diffuse enhancement followed the convolutions of gyri and surface of brainstem, and extended into cerebral cisterns and sulci. the foci appeared as enhanced nodules 0.2-3.0 cm in diameter and 1 or more in number. Nodules with infiltration of cerebral parenchymal were found in 4 patients. In 86% of all cases, diffuse or nodular foci occurred in basilar systems and adjacent cerebellar and cerebral sulci. There were 4 cases associated with ependymal nodular enhancement and 10 cases with widened irregular tentorial enhancement. Intracerebral metastases in 9 cases and hydrocephalus in 13 cases were found in this series. Conclusions: CE-CT and Gd-MRI are had significant clinical diagnostic value for leptomeningeal metastases, Gd-MRI is superior to CE-CT. Because of the limitation in the evaluation of leptomeningeal invasion by neoplasms on CT and MRI, definitive diagnosis of leptomeningeal metastases depends on combination of clinical and imaging data

Impacts of Policies on Poverty: The Definition of Poverty

OpenAIRE

Bellù, Lorenzo Giovanni; Liberati, Paolo

2005-01-01

This module illustrates how poverty can be defined in the context of policy impact analysis. After reporting and discussing the definition of poverty as “the lack of, or the inability to achieve, a socially acceptable standard of living”, it discusses the mono-dimensional and multi-dimensional approaches to the definition of poverty. Furthermore, the module focuses on the absolute and the relative concept of poverty, also drawing some analogies and differences with the concept of food secu...

Dosimetric comparison of stereotactic body radiotherapy using 4D CT and multiphase CT images for treatment planning of lung cancer: Evaluation of the impact on daily dose coverage

International Nuclear Information System (INIS)

Wang Lu; Hayes, Shelly; Paskalev, Kamen; Jin Lihui; Buyyounouski, Mark K.; Ma, Charlie C.-M.; Feigenberg, Steve

2009-01-01

Purpose: To investigate the dosimetric impact of using 4D CT and multiphase (helical) CT images for treatment planning target definition and the daily target coverage in hypofractionated stereotactic body radiotherapy (SBRT) of lung cancer. Materials and methods: For 10 consecutive patients treated with SBRT, a set of 4D CT images and three sets of multiphase helical CT scans, taken during free-breathing, end-inspiration and end-expiration breath-hold, were obtained. Three separate planning target volumes (PTVs) were created from these image sets. A PTV 4D was created from the maximum intensity projection (MIP) reconstructed 4D images by adding a 3 mm margin to the internal target volume (ITV). A PTV 3CT was created by generating ITV from gross target volumes (GTVs) contoured from the three multiphase images. Finally, a third conventional PTV (denoted PTV conv ) was created by adding 5 mm in the axial direction and 10 mm in the longitudinal direction to the GTV (in this work, GTV = CTV = clinical target volume) generated from free-breathing helical CT scans. Treatment planning was performed based on PTV 4D (denoted as Plan-1), and the plan was adopted for PTV 3CT and PTV conv to form Plan-2 and Plan-3, respectively, by superimposing 'Plan-1' onto the helical free-breathing CT data set using modified beam apertures that conformed to either PTV 3CT or PTV conv . We first studied the impact of PTV design on treatment planning by evaluating the dosimetry of the three PTVs under the three plans, respectively. Then we examined the effect of the PTV designs on the daily target coverage by utilizing pre-treatment localization CT (CT-on-rails) images for daily GTV contouring and dose recalculation. The changes in the dose parameters of D 95 and D 99 (the dose received by 95% and 99% of the target volume, respectively), and the V p (the volume receiving the prescription dose) of the daily GTVs were compared under the three plans before and after setup error correction

CT diagnosis of thyroid carcinoma

International Nuclear Information System (INIS)

Luo Dehong; Shi Mulan; Luo Douqiang

1998-01-01

Purpose: To study the CT appearances of thyroid carcinoma and its cervical metastatic lymphadenopathy, as well as to evaluate the diagnostic criteria of tumor invasion of adjacent structures. Methods: CT findings of surgery and pathology proved thyroid carcinoma in 52 patients were analyzed. Results: All of the primary tumor were heterogeneous in density, 32 tumors (82.5%) were ill-defined. Fine granular calcifications were revealed in 11 primary tumors and metastatic lymph nodes in 5 cases. Cystic formation with intracystic high density papillary-like nodules were found in 4 primary tumors and metastatic lymphadenopathy in 5 cases. Trachea, esophagus and carotic artery invasion were proved by surgery in 22, 21 and 10 cases respectively. Serrated inner wall and tumor nodule protrusion into tracheal lumen were the definite signs of trachea invasion. Use tumor encasement over 1/2 of the circumference of esophagus and 1/3 of the circumference of carotid artery as the diagnostic criterion of invasion, sensitivity was 71.4%, 100.0% specificity was 96.3%, 95.2% respectively. Conclusion: Fine granular calcification and cystic formation with high attenuation intracystic papillary-like nodules were characteristic manifestations of primary thyroid carcinoma (especially papillary carcinoma) and its metastatic lymphadenopathy as well. Contrast enhanced CT scan is helpful in the diagnosis of thyroid carcinoma and the delineation of tumor extent, which is very important in surgical planning

Teamwork: a concept analysis.

Science.gov (United States)

Xyrichis, Andreas; Ream, Emma

2008-01-01

This paper is a report of an analysis of the concept of teamwork. Teamwork is seen as an important facilitator in delivering quality healthcare services internationally. However, research studies of teamwork in health care are criticized for lacking a basic conceptual understanding of what this concept represents. A universal definition for healthcare settings and professionals is missing from published literature. Walker and Avant's approach was used to guide this concept analysis. Literature searches used bibliographic databases (Medline, CINAHL, Web of Science, Proquest CSA), internet search engines (GoogleScholar), and hand searches. Literature published between 1976 and 2006 was reviewed but only material in English was included. Based on the analysis undertaken, teamwork is proposed as a dynamic process involving two or more healthcare professionals with complementary backgrounds and skills, sharing common health goals and exercising concerted physical and mental effort in assessing, planning, or evaluating patient care. This is accomplished through interdependent collaboration, open communication and shared decision-making, and generates value-added patient, organizational and staff outcomes. Praising the value of teamwork without a common understanding of what this concept represents endangers both research into this way of working and its effective utilization in practice. The proposed definition helps reconcile discrepancies between how this concept is understood by nurses and doctors, as well as allied health professionals. A common understanding can facilitate communication in educational, research and clinical settings and is imperative for improving clarity and validity of future research.

CT simulation in nodal positive breast cancer

International Nuclear Information System (INIS)

Horst, E.; Schuck, A.; Moustakis, C.; Schaefer, U.; Micke, O.; Kronholz, H.L.; Willich, N.

2001-01-01

Background: A variety of solutions are used to match tangential fields and opposed lymph node fields in irradiation of nodal positive breast cancer. The choice is depending on the technical equipment which is available and the clinical situation. The CT simulation of a non-monoisocentric technique was evaluated in terms of accuracy and reproducibility. Patients, Material and Methods: The field match parameters were adjusted virtually at CT simulation and were compared with parameters derived mathematically. The coordinate transfer from the CT simulator to the conventional simulator was analyzed in 25 consecutive patients. Results: The angles adjusted virtually for a geometrically exact coplanar field match corresponded with the angles calculated for each set-up. The mean isocenter displacement was 5.7 mm and the total uncertainty of the coordinate transfer was 6.7 mm (1 SD). Limitations in the patient set-up became obvious because of the steep arm abduction necessary to fit the 70 cm CT gantry aperture. Required modifications of the arm position and coordinate transfer errors led to a significant shift of the marked matchline of >1.0 cm in eight of 25 patients (32%). Conclusion: The virtual CT simulation allows a precise and graphic definition of the field match parameters. However, modifications of the virtual set-up basically due to technical limitations were required in a total of 32% of cases, so that a hybrid technique was adapted at present that combines virtual adjustment of the ideal field alignment parameters with conventional simulation. (orig.) [de

Some problems of special theory of relativity. (Concept of relativistic length)

International Nuclear Information System (INIS)

Strel'tsov, V.N.

1977-01-01

Two available definitions of the concept of length (distance) related (a) to moving the length standard and (b) to sending a light signal (similar to the radar method for measuring distances) are analyzed. Considerations in favour of the preferable use of the (b) definition are discussed. The extension of the (b) definition for fast moving bodies results in the introduction of the definition of relativistic length and volume. The increase of the longitudinal dimensions of fast moving objects is a consequence of the above definition. It should be noted that, e.g., for a rod, the definition corresponds to measurements on the lines orthogonal to the world strip of the given rod. It is shown that the known Michelson-Morley and Throuton-Noble experiments are naturally explained in the framework of the proposed concept of relativistic length. It is also shown that the definition introduced, unlike the conventional one, satisfies the principle of relativity

Intentional learning: A concept analysis.

Science.gov (United States)

Mollman, Sarah; Candela, Lori

2018-01-01

To use a concept analysis to determine a clear definition of the term "intentional learning" for use in nursing. The term intentional learning has been used for years in educational, business, and even nursing literature. It has been used to denote processes leading to higher order thinking and the ability to use knowledge in new situations; both of which are important skills to develop in nursing students. But the lack of a common, accepted definition of the term makes it difficult for nurse educators to base instruction and learning experiences on or to evaluate its overall effectiveness in educating students for diverse, fast-paced clinical practices. A concept analysis following the eight-step method developed by Walker and Avant (2011). Empirical and descriptive literature.  Five defining attributes were identified: (1) self-efficacy for learning, (2) active, effortful, and engaged learning, (3) mastery of goals where learning is the goal, (4) self-directed learning, and (5) self-regulation of learning. Through this concept analysis, nursing will have a clear definition of intentional learning. This will enable nurse educators to generate, evaluate, and test learning experiences that promote further development of intentional learning in nursing students. Nurses in practice will also be able to evaluate if the stated benefits are demonstrated and how this impacts patient care and outcomes. © 2017 Wiley Periodicals, Inc.

Estimation and comparison of effective dose (E) in standard chest CT by organ dose measurements and dose-length-product methods and assessment of the influence of CT tube potential (energy dependency) on effective dose in a dual-source CT.

Science.gov (United States)

Paul, Jijo; Banckwitz, Rosemarie; Krauss, Bernhard; Vogl, Thomas J; Maentele, Werner; Bauer, Ralf W

2012-04-01

To determine effective dose (E) during standard chest CT using an organ dose-based and a dose-length-product-based (DLP) approach for four different scan protocols including high-pitch and dual-energy in a dual-source CT scanner of the second generation. Organ doses were measured with thermo luminescence dosimeters (TLD) in an anthropomorphic male adult phantom. Further, DLP-based dose estimates were performed by using the standard 0.014mSv/mGycm conversion coefficient k. Examinations were performed on a dual-source CT system (Somatom Definition Flash, Siemens). Four scan protocols were investigated: (1) single-source 120kV, (2) single-source 100kV, (3) high-pitch 120kV, and (4) dual-energy with 100/Sn140kV with equivalent CTDIvol and no automated tube current modulation. E was then determined following recommendations of ICRP publication 103 and 60 and specific k values were derived. DLP-based estimates differed by 4.5-16.56% and 5.2-15.8% relatively to ICRP 60 and 103, respectively. The derived k factors calculated from TLD measurements were 0.0148, 0.015, 0.0166, and 0.0148 for protocol 1, 2, 3 and 4, respectively. Effective dose estimations by ICRP 103 and 60 for single-energy and dual-energy protocols show a difference of less than 0.04mSv. Estimates of E based on DLP work equally well for single-energy, high-pitch and dual-energy CT examinations. The tube potential definitely affects effective dose in a substantial way. Effective dose estimations by ICRP 103 and 60 for both single-energy and dual-energy examinations differ not more than 0.04mSv. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

The niche party concept and its measurement.

Science.gov (United States)

Meyer, Thomas M; Miller, Bernhard

2015-03-01

The concept of the niche party has become increasingly popular in analyses of party competition. Yet, existing approaches vary in their definitions and their measurement approaches. We propose using a minimal definition that allows us to compare political parties in terms of their 'nicheness'. We argue that the conceptual core of the niche party concept is based on issue emphasis and that a niche party emphasizes policy areas neglected by its rivals. Based on this definition, we propose a continuous measure that allows for more fine-grained measurement of a party's 'nicheness' than the dominant, dichotomous approaches and thereby limits the risk of measurement error. Drawing on data collected by the Comparative Manifesto Project, we show that (1) our measure has high face validity and (2) exposes differences among parties that are not captured by alternative, static or dichotomous measures.

Spiritual nursing care: A concept analysis.

Science.gov (United States)

Monareng, Lydia V

2012-10-08

Although the concept 'spiritual nursing care' has its roots in the history of the nursing profession, many nurses in practice have difficulty integrating the concept into practice. There is an ongoing debate in the empirical literature about its definition, clarity and application in nursing practice. The study aimed to develop an operational definition of the concept and its application in clinical practice. A qualitative study was conducted to explore and describe how professional nurses render spiritual nursing care. A purposive sampling method was used to recruit the sample. Individual and focus group interviews were audio-taped and transcribed verbatim. Trustworthiness was ensured through strategies of truth value, applicability, consistency and neutrality. Data were analysed using the NUD*IST power version 4 software, constant comparison, open, axial and selective coding. Tech's eight steps of analysis were also used, which led to the emergence of themes, categories and sub-categories. Concept analysis was conducted through a comprehensive literature review and as a result 'caring presence' was identified as the core variable from which all the other characteristics of spiritual nursing care arise. An operational definition of spiritual nursing care based on the findings was that humane care is demonstrated by showing caring presence, respect and concern for meeting the needs not only of the body and mind of patients, but also their spiritual needs of hope and meaning in the midst of health crisis, which demand equal attention for optimal care from both religious and nonreligious nurses.

A 4D global respiratory motion model of the thorax based on CT images: A proof of concept.

Science.gov (United States)

Fayad, Hadi; Gilles, Marlene; Pan, Tinsu; Visvikis, Dimitris

2018-05-17

Respiratory motion reduces the sensitivity and specificity of medical images especially in the thoracic and abdominal areas. It may affect applications such as cancer diagnostic imaging and/or radiation therapy (RT). Solutions to this issue include modeling of the respiratory motion in order to optimize both diagnostic and therapeutic protocols. Personalized motion modeling required patient-specific four-dimensional (4D) imaging which in the case of 4D computed tomography (4D CT) acquisition is associated with an increased dose. The goal of this work was to develop a global respiratory motion model capable of relating external patient surface motion to internal structure motion without the need for a patient-specific 4D CT acquisition. The proposed global model is based on principal component analysis and can be adjusted to a given patient anatomy using only one or two static CT images in conjunction with a respiratory synchronized patient external surface motion. It is based on the relation between the internal motion described using deformation fields obtained by registering 4D CT images and patient surface maps obtained either from optical imaging devices or extracted from CT image-based patient skin segmentation. 4D CT images of six patients were used to generate the global motion model which was validated by adapting it on four different patients having skin segmented surfaces and two other patients having time of flight camera acquired surfaces. The reproducibility of the proposed model was also assessed on two patients with two 4D CT series acquired within 2 weeks of each other. Profile comparison shows the efficacy of the global respiratory motion model and an improvement while using two CT images in order to adapt the model. This was confirmed by the correlation coefficient with a mean correlation of 0.9 and 0.95 while using one or two CT images respectively and when comparing acquired to model generated 4D CT images. For the four patients with segmented

Diagnostic Accuracy of MRI Versus CT for the Evaluation of Acute Appendicitis in Children and Young Adults.

Science.gov (United States)

Kinner, Sonja; Pickhardt, Perry J; Riedesel, Erica L; Gill, Kara G; Robbins, Jessica B; Kitchin, Douglas R; Ziemlewicz, Timothy J; Harringa, John B; Reeder, Scott B; Repplinger, Michael D

2017-10-01

Appendicitis is frequently diagnosed in the emergency department, most commonly using CT. The purpose of this study was to compare the diagnostic accuracy of contrast-enhanced MRI with that of contrast-enhanced CT for the diagnosis of appendicitis in adolescents when interpreted by abdominal radiologists and pediatric radiologists. Our study included a prospectively enrolled cohort of 48 patients (12-20 years old) with nontraumatic abdominal pain who underwent CT and MRI. Fellowship-trained abdominal and pediatric radiologists reviewed all CT and MRI studies in randomized order, blinded to patient outcome. Likelihood for appendicitis was rated on a 5-point scale (1, definitely not appendicitis; 5, definitely appendicitis) for CT, the unenhanced portion of the MRI, and the entire contrast-enhanced MRI study. ROC curves were generated and AUC compared for each scan type for all six readers and then stratified by radiologist type. Image test characteristics, interrater reliability, and reading times were compared. Sensitivity and specificity were 85.9% (95% CI, 76.2-92.7%) and 93.8% (95% CI, 89.7-96.7%) for unenhanced MRI, 93.6% (95% CI, 85.6-97.9%) and 94.3% (95% CI, 90.2-97%) for contrast-enhanced MRI, and 93.6% (95% CI, 85.6-97.9%) and 94.3% (95% CI, 90.2-97%) for CT. No difference was found in the diagnostic accuracy or interpretation time when comparing abdominal radiologists to pediatric radiologists (CT, 3.0 min vs 2.8 min; contrast-enhanced MRI, 2.4 min vs 1.8 min; unenhanced MRI, 1.5 min vs 2.3 min). Substantial agreement between abdominal and pediatric radiologists was seen for all methods (κ = 0.72-0.83). The diagnostic accuracy of MRI to diagnose appendicitis was very similar to CT. No statistically significant difference in accuracy was observed between imaging modality or radiologist subspecialty.

Systematisation of spatial uncertainties for comparison between a MR and a CT-based radiotherapy workflow for prostate treatments

International Nuclear Information System (INIS)

Nyholm, Tufve; Nyberg, Morgan; Karlsson, Magnus G; Karlsson, Mikael

2009-01-01

In the present work we compared the spatial uncertainties associated with a MR-based workflow for external radiotherapy of prostate cancer to a standard CT-based workflow. The MR-based workflow relies on target definition and patient positioning based on MR imaging. A solution for patient transport between the MR scanner and the treatment units has been developed. For the CT-based workflow, the target is defined on a MR series but then transferred to a CT study through image registration before treatment planning, and a patient positioning using portal imaging and fiducial markers. An 'open bore' 1.5T MRI scanner, Siemens Espree, has been installed in the radiotherapy department in near proximity to a treatment unit to enable patient transport between the two installations, and hence use the MRI for patient positioning. The spatial uncertainty caused by the transport was added to the uncertainty originating from the target definition process, estimated through a review of the scientific literature. The uncertainty in the CT-based workflow was estimated through a literature review. The systematic uncertainties, affecting all treatment fractions, are reduced from 3-4 mm (1Sd) with a CT based workflow to 2-3 mm with a MR based workflow. The main contributing factor to this improvement is the exclusion of registration between MR and CT in the planning phase of the treatment. Treatment planning directly on MR images reduce the spatial uncertainty for prostate treatments

Radiotherapy volume delineation using 18F-FDG-PET/CT modifies gross node volume in patients with oesophageal cancer.

Science.gov (United States)

Jimenez-Jimenez, E; Mateos, P; Aymar, N; Roncero, R; Ortiz, I; Gimenez, M; Pardo, J; Salinas, J; Sabater, S

2018-05-02

Evidence supporting the use of 18F-FDG-PET/CT in the segmentation process of oesophageal cancer for radiotherapy planning is limited. Our aim was to compare the volumes and tumour lengths defined by fused PET/CT vs. CT simulation. Twenty-nine patients were analyzed. All patients underwent a single PET/CT simulation scan. Two separate GTVs were defined: one based on CT data alone and another based on fused PET/CT data. Volume sizes for both data sets were compared and the spatial overlap was assessed by the Dice similarity coefficient (DSC). The gross tumour volume (GTVtumour) and maximum tumour diameter were greater by PET/CT, and length of primary tumour was greater by CT, but differences were not statistically significant. However, the gross node volume (GTVnode) was significantly greater by PET/CT. The DSC analysis showed excellent agreement for GTVtumour, 0.72, but was very low for GTVnode, 0.25. Our study shows that the volume definition by PET/CT and CT data differs. CT simulation, without taking into account PET/CT information, might leave cancer-involved nodes out of the radiotherapy-delineated volumes.

Extraction of UMLS® Concepts Using Apache cTAKES™ for German Language.

Science.gov (United States)

Becker, Matthias; Böckmann, Britta

2016-01-01

Automatic information extraction of medical concepts and classification with semantic standards from medical reports is useful for standardization and for clinical research. This paper presents an approach for an UMLS concept extraction with a customized natural language processing pipeline for German clinical notes using Apache cTAKES. The objectives are, to test the natural language processing tool for German language if it is suitable to identify UMLS concepts and map these with SNOMED-CT. The German UMLS database and German OpenNLP models extended the natural language processing pipeline, so the pipeline can normalize to domain ontologies such as SNOMED-CT using the German concepts. For testing, the ShARe/CLEF eHealth 2013 training dataset translated into German was used. The implemented algorithms are tested with a set of 199 German reports, obtaining a result of average 0.36 F1 measure without German stemming, pre- and post-processing of the reports.

Prevalence of ligamentum arteriosum calcification on multi-section spiral CT and digital radiography.

Science.gov (United States)

Hong, Gil-Sun; Goo, Hyun Woo; Song, Jae-Woo

2012-06-01

To investigate the prevalence of ligamentum arteriosum calcification (LAC) on multi-section spiral CT and digital radiography. Five hundred and eight children and 232 adults who performed multi-section chest CT were included in this study and were divided into nine age groups: A (0-5 years), B (6-10 years), C (11-15 years), D (16-20 years), E (21-30 years), F (31-40 years), G (41-50 years), H (51-60 years), and I (61-70 years). Two radiologists assessed the presence of LAC on axial and coronal CT images, defined as focal calcific density on both or on one plane with attenuation >100 Hounsfield unit. The prevalence of LAC on CT was compared between children and adults, and between unenhanced and enhanced CT in children. The prevalence of LAC on digital radiography was evaluated in 476 children. The prevalence of definite LAC on unenhanced multi-section CT was significantly higher in children (37.8 %) than in adults (11.2 %) (P CT were 4.5, 12.8, 8.1, 19.0, 0.0, 0.0, 0.0, 2.0, and 1.9 %. In children, the prevalence of LAC was significantly higher on unenhanced than on enhanced CT (37.8 vs. 16.4 %, P children. LAC is frequently observed in children and adults on multi-section spiral CT, more frequently than previously reported. Compared with that on multi-section spiral CT, the prevalence of LAC on digital radiography is substantially low.

A proposed lexicon of terms and concepts for human-bear management in North America

Science.gov (United States)

Hopkins, John B.; Herrero, Stephen; Shideler, Richard T.; Gunther, Kerry A.; Schwartz, Charles C.; Kalinowski, Steven T.

2010-01-01

We believe that communication within and among agency personnel in the United States and Canada about the successes and failures of their human–bear (Ursidae) management programs will increase the effectiveness of these programs and of bear research. To communicate more effectively, we suggest agencies clearly define terms and concepts used in human–bear management and use them in a consistent manner. We constructed a human–bear management lexicon of terms and concepts using a modified Delphi method to provide a resource that facilitates more effective communication among human–bear management agencies. Specifically, we defined 40 terms and concepts in human–bear management and suggest definitions based on discussions with 13 other professionals from the United States and Canada. Although new terms and concepts will emerge in the future and definitions will evolve as we learn more about bear behavior and ecology, our purpose is to suggest working definitions for terms and concepts to help guide human–bear management and research activities in North America. Applications or revisions of these definitions may be useful outside of North America.

Comparison of CT numbers between cone-beam CT and multi-detector CT

International Nuclear Information System (INIS)

Kim, Dong Soo; Han, Won Jeong; Kim, Eun Kyung

2010-01-01

To compare the CT numbers on 3 cone-beam CT (CBCT) images with those on multi-detector CT (MDCT) image using CT phantom and to develop linear regressive equations using CT numbers to material density for all the CT scanner each. Mini CT phantom comprised of five 1 inch thick cylindrical models with 1.125 inches diameter of materials with different densities (polyethylene, polystyrene, plastic water, nylon and acrylic) was used. It was scanned in 3 CBCTs (i-CAT, Alphard VEGA, Implagraphy SC) and 1 MDCT (Somatom Emotion). The images were saved as DICOM format and CT numbers were measured using OnDemand 3D. CT numbers obtained from CBCTs and MDCT images were compared and linear regression analysis was performed for the density, ρ(g/cm 3 ), as the dependent variable in terms of the CT numbers obtained from CBCTs and MDCT images. CT numbers on i-CAT and Implagraphy CBCT images were smaller than those on Somatom Emotion MDCT image (p<0.05). Linear relationship on a range of materials used for this study were ρ=0.001 H+1.07 with R2 value of 0.999 for Somatom Emotion, ρ=0.002 H+1.09 with R2 value of 0.991 for Alphard VEGA, ρ=0.001 H+1.43 with R2 value of 0.980 for i-CAT and ρ=0.001 H+1.30 with R2 value of 0.975 for Implagraphy. CT numbers on i-CAT and Implagraphy CBCT images were not same as those on Somatom Emotion MDCT image. The linear regressive equations to determine the density from the CT numbers with very high correlation coefficient were obtained on three CBCT and MDCT scan.

Comparison of CT numbers between cone-beam CT and multi-detector CT

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong Soo; Han, Won Jeong; Kim, Eun Kyung [Department of Oral and Maxillofacial Radiology, School of Dentistry, Dankook University, Cheonan (Korea, Republic of)

2010-06-15

To compare the CT numbers on 3 cone-beam CT (CBCT) images with those on multi-detector CT (MDCT) image using CT phantom and to develop linear regressive equations using CT numbers to material density for all the CT scanner each. Mini CT phantom comprised of five 1 inch thick cylindrical models with 1.125 inches diameter of materials with different densities (polyethylene, polystyrene, plastic water, nylon and acrylic) was used. It was scanned in 3 CBCTs (i-CAT, Alphard VEGA, Implagraphy SC) and 1 MDCT (Somatom Emotion). The images were saved as DICOM format and CT numbers were measured using OnDemand 3D. CT numbers obtained from CBCTs and MDCT images were compared and linear regression analysis was performed for the density, {rho}(g/cm{sup 3}), as the dependent variable in terms of the CT numbers obtained from CBCTs and MDCT images. CT numbers on i-CAT and Implagraphy CBCT images were smaller than those on Somatom Emotion MDCT image (p<0.05). Linear relationship on a range of materials used for this study were {rho}=0.001 H+1.07 with R2 value of 0.999 for Somatom Emotion, {rho}=0.002 H+1.09 with R2 value of 0.991 for Alphard VEGA, {rho}=0.001 H+1.43 with R2 value of 0.980 for i-CAT and {rho}=0.001 H+1.30 with R2 value of 0.975 for Implagraphy. CT numbers on i-CAT and Implagraphy CBCT images were not same as those on Somatom Emotion MDCT image. The linear regressive equations to determine the density from the CT numbers with very high correlation coefficient were obtained on three CBCT and MDCT scan.

Added diagnostic benefit of 16-row whole-body spiral CT in patients with multiple trauma differentiated by region and injury severity according to the ATLS registered concept

International Nuclear Information System (INIS)

Maurer, M.H.; Knopke, S.; Schroeder, R.J.

2008-01-01

Purpose: to determine the added diagnostic benefit of using MS-CT in multiple trauma patients differentiated by severity of injury and affected body region. Materials and methods: a retrospective analysis was performed of the 16-row whole-body spiral CT findings in 275 multiple trauma patients (73% men, 27% women; age 39.6 ± 18.9 years) with regard to additional findings and new findings obtained with CT compared to the findings obtained by conventional projection radiography and abdominal ultrasound in the emergency room. The additional and new findings were differentiated by body region (head, face, chest, pelvis, abdomen, spine) and the degree of severity according to the three classes of injuries distinguished by the ATLS registered concept (class 1: simple injury, class 2: potentially life threatening, class 3: immediately life threatening). Results: a total of 921 additional findings (findings potentially relevant for further diagnosis and therapy in addition to the findings obtained by conventional radiography or ultrasound) were obtained by MS-CT in all patients. The distribution by number of patients and body region was as follows: 22 neck, 76 face, 125 chest, 112 abdomen, 50 pelvis, and 91 spine. Most additional findings were categorized as potentially life threatening (ATLS class 2). In addition, there were 439 completely new findings, involving the head in 128 patients (mostly ATLS class 3), the face in 18, the chest in 47, the abdomen in 26, and the spine in 9 patients. Most new findings involving the face, abdomen, and spine were ATLS class 2 injuries. (orig.)

CT-guided stereotactic evacuation of hypertensive intracerebral hematomas

International Nuclear Information System (INIS)

Hondo, Hideki

1983-01-01

Computerized tomography (CT) is now effective not only for definite diagnosis and location of intracerebral hematomas but also for coordination of the center of a hematoma. CT-guided stereotactic evacuation of hypertensive intracerebral hematoma was performed in 51 cases: 34 of basal ganglionic hematoma with or without ventricular perforation, 11 of subcortical hematoma, 3 of thalamic hematoma and 3 of cerebellar hematoma. Three dimensional CT images or biplane CT images were taken to determine the coordinates of the target point, which was the center of the hematoma. Then, a silicon tube (O.D. 3.5 phi, I.D. 2.1 phi) was inserted into the center of the hematoma through a burr-hole under local anesthesia, and the liquid or solid hematoma was aspirated as completely as possible with a syringe. Urokinase (6,000 I.U./5 ml saline) was administered through this silicon tube every 6 or 12 hours for several days until the hematoma had drained out competely. The silicon tube was taken out when repeated CT scanning revealed no hematoma. The results of clinical follow-ups indicated that this procedure is as good as, or rather better than conventional microsurgery with evacuation of hematoma under direct vision. Moreover this CT-guided stereotactic approach for evacuation of the hematoma has the following advantages: 1) the procedure is simple and safe, 2) operation can be performed under local anesthesia, and 3) the hematoma is drained out completely with the aid of urokinase. This surgery seems indicated as an emergency treatment for high-age or high risk patients and also as a routine surgery for intracerebral hematomas in patients showing no herination signs. (author)

VSCE technology definition study

Science.gov (United States)

Howlett, R. A.; Hunt, R. B.

1979-01-01

Refined design definition of the variable stream control engine (VSCE) concept for advanced supersonic transports is presented. Operating and performance features of the VSCE are discussed, including the engine components, thrust specific fuel consumption, weight, noise, and emission system. A preliminary engine design is presented.

A Concept Analysis of Attitude toward Getting Vaccinated against Human Papillomavirus

Science.gov (United States)

Ratanasiripong, Nop T.; Chai, Kathleen T.

2013-01-01

In the research literature, the concept of attitude has been used and presented widely. However, attitude has been inconsistently defined and measured in various terms. This paper presents a concept analysis, using the Wilsonian methods modified by Walker and Avant (2004), to define and clarify the concept of attitude in order to provide an operationalized definition for a research study on attitudes toward a behavior: getting vaccinated against HPV. While the finding is not conclusive, three attributes of attitude: belief, affection, and evaluation are described. A theoretical definition and sample cases are constructed to illustrate the concept further. Antecedents, consequences, and empirical referents are discussed. Recommendations regarding the use of the concept of attitude in research, nursing practice, and nursing education are also made. PMID:23781335

Informatics with Systems Science and Cybernetics--Concepts and Definitions.

Science.gov (United States)

Samuelson, Kjell

This dictionary defines information science, computer science, systems theory, and cybernetic terms in English and provides the Swedish translation of each term. An index of Swedish terms refers the user to the page where the English equivalent and definition appear. Most of the 38 references listed are in English. (RAA)

Usefulness of MR imaging for diseases of the small intestine: comparison with CT

Energy Technology Data Exchange (ETDEWEB)

Kim, Ji Hoon; Ha, Hyun Kwon; Sohn, Min Jae; Shin, Byung Suck; Lee, Young Suk; Chung, Soo Yoon; Kim, Pyo Nyun; Lee, Moon Gyu; Auh, Yong Ho [Ulsan University College of Medicine, Seoul (Korea, Republic of)

2000-03-01

To evaluate the usefulness of MR imaging for diseases of the small intestine, emphasizing a comparison with CT. Thirty-four patients who underwent both CT and MR imaging using FLASH 2D and HASTE sequences were analyzed. All patients had various small bowel diseases with variable association of peritoneal lesions. We compared the detectabilities of CT and MR imaging using different MR pulse sequences. The capability for analyzing the characteristics of small intestinal disease was also compared. MR imaging was nearly equal to CT for detecting intraluminal or peritoneal masses, lesions in the bowel and mesentery, and small bowel obstruction, but was definitely inferior for detecting omental lesions. The most successful MR imaging sequence was HASTE for demonstrating bowel wall thickening, coronal FLASH 2D for mesenteric lesions, and axial FLASH 2D for omental lesions. MR imaging yielded greater information than CT in six of 12 inflammatory bowel diseases, while it was equal to CT in six of seven neoplasms and inferior in five of seven mesenteric ischemia. In determining the primary causes of 15 intestinal obstructions, MR imaging was correct in 11 (73%) and CT in nine (60%) patients. MR imaging can serve as an alternative diagnostic tool for patients with suspected inflammatory bowel disease, small intestinal neoplasm or obstruction.

Innovation in gynaecological brachytherapy: new technologies, pulse dose-rate brachytherapy, image, definition of new volumes of interest and their impact on dosimetry: application in a clinical research programme 'S.T.I.C.'

International Nuclear Information System (INIS)

Haie-Meder, C.; Peiffert, D.

2006-01-01

Brachytherapy plays a fundamental role in the therapeutic approach of patients with stage I-IV cervical carcinoma. Technical modalities have evolved during the last decades: stepping source technology, imaging modalities development, specially IMN, treatment planning system integrating 3D images. Images from CT-Scan and MRI have contributed to a better knowledge of tumoral extension and critical organs. CT and/or MRI compatible applicators allow a sectional image based approach with a better definition of tumour volume compared to traditional approaches. The introduction of 3D image based approach for GTV and CTV requires new definitions and a common language. In 2000, a working group within GEC-ESTRO was created to support 3D image based 3D treatment planning approach in cervix cancer BT. The task was to determine a common terminology enabling various groups to use a common language. Recommendations were described and proposed based on clinical experience and dosimetric concepts of different institutions. Two CTVs were described en relation to the risk for recurrence: high-risk CTV and intermediate risk CTV. In order to better define the role of such definitions and their potential impact on the complication incidence in patients with cervical cancer, a special French programme was developed. The aim of this programme is to study the incidence of the severe 2-year complication rate in two comparable patient populations: one population is treated using PDR brachytherapy with CT-Scan or MRI with the applicators in place allowing a 3D dosimetry with optimization, the second population is treated using standard X-rays radiographs, without any delineation of the target nor optimisation. Each population arm includes 425 patients. A medico-economic assessment is performed, allowing a real cost of the most sophisticated approach compared to a historical dosimetric system. (author)

Equivalence of the Traditional and Non-Standard Definitions of Concepts from Real Analysis

Directory of Open Access Journals (Sweden)

John Cowles

2014-06-01

Full Text Available ACL2(r is a variant of ACL2 that supports the irrational real and complex numbers. Its logical foundation is based on internal set theory (IST, an axiomatic formalization of non-standard analysis (NSA. Familiar ideas from analysis, such as continuity, differentiability, and integrability, are defined quite differently in NSA–some would argue the NSA definitions are more intuitive. In previous work, we have adopted the NSA definitions in ACL2(r, and simply taken as granted that these are equivalent to the traditional analysis notions, e.g., to the familiar epsilon-delta definitions. However, we argue in this paper that there are circumstances when the more traditional definitions are advantageous in the setting of ACL2(r, precisely because the traditional notions are classical, so they are unencumbered by IST limitations on inference rules such as induction or the use of pseudo-lambda terms in functional instantiation. To address this concern, we describe a formal proof in ACL2(r of the equivalence of the traditional and non-standards definitions of these notions.

Transcranial sonography: integration into target volume definition for glioblastoma multiforme

International Nuclear Information System (INIS)

Vordermark, Dirk; Becker, Georg; Flentje, Michael; Richter, Susanne; Goerttler-Krauspe, Irene; Koelbl, Oliver

2000-01-01

Purpose: Recent studies indicate that transcranial sonography (TCS) reliably displays the extension of malignant brain tumors. The effect of integrating TCS into radiotherapy planning for glioblastoma multiforme (GBM) was investigated herein. Methods and Materials: Thirteen patients subtotally resected for GBM underwent TCS during radiotherapy planning and were conventionally treated (54 to 60 Gy). Gross tumor volumes (GTVs) and stereotactic boost planning target volumes (PTVs, 3-mm margin) were created, based on contrast enhancement on computed tomography (CT) only (PTV CT ) or the combined CT and TCS information (PTV CT+TCS ). Noncoplonar conformal treatment plans for both PTVs were compared. Tumor progression patterns and preoperative magnetic resonance imaging (MRI) were related to both PTVs. Results: A sufficient temporal bone window for TCS was present in 11 of 13 patients. GTVs as defined by TCS were considerably larger than the respective CT volumes: Of the composite GTV CT+TCS (median volume 42 ml), 23%, 13%, and 66% (medians) were covered by the overlap of both methods, CT only and TCS only, respectively. Median sizes of PTV CT and PTV CT+TCS were 34 and 74 ml, respectively. Addition of TCS to CT information led to a median increase of the volume irradiated within the 80% isodose by 32 ml (median factor 1.51). PTV CT+TCS volume was at median 24% of a 'conventional' MRI(T2)-based PTV. Of eight progressions analyzed, three and six occurred inside the 80% isodose of the plans for PTV CT and for PTV CT+TCS , respectively. Conclusion: Addition of TCS tumor volume to the contrast-enhancing CT volume in postoperative radiotherapy planning for GBM increases the treated volume by a median factor of 1.5. Since a high frequency of marginal recurrences is reported from dose-escalation trials of this disease, TCS may complement established methods in PTV definition

Team-Based Care: A Concept Analysis.

Science.gov (United States)

Baik, Dawon

2017-10-01

The purpose of this concept analysis is to clarify and analyze the concept of team-based care in clinical practice. Team-based care has garnered attention as a way to enhance healthcare delivery and patient care related to quality and safety. However, there is no consensus on the concept of team-based care; as a result, the lack of common definition impedes further studies on team-based care. This analysis was conducted using Walker and Avant's strategy. Literature searches were conducted using PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and PsycINFO, with a timeline from January 1985 to December 2015. The analysis demonstrates that the concept of team-based care has three core attributes: (a) interprofessional collaboration, (b) patient-centered approach, and (c) integrated care process. This is accomplished through understanding other team members' roles and responsibilities, a climate of mutual respect, and organizational support. Consequences of team-based care are identified with three aspects: (a) patient, (b) healthcare professional, and (c) healthcare organization. This concept analysis helps better understand the characteristics of team-based care in the clinical practice as well as promote the development of a theoretical definition of team-based care. © 2016 Wiley Periodicals, Inc.

Characterizing semantic mappings adaptation via biomedical KOS evolution: a case study investigating SNOMED CT and ICD.

Science.gov (United States)

Dos Reis, Julio Cesar; Pruski, Cédric; Da Silveira, Marcos; Reynaud-Delaître, Chantal

2013-01-01

Mappings established between Knowledge Organization Systems (KOS) increase semantic interoperability between biomedical information systems. However, biomedical knowledge is highly dynamic and changes affecting KOS entities can potentially invalidate part or the totality of existing mappings. Understanding how mappings evolve and what the impacts of KOS evolution on mappings are is therefore crucial for the definition of an automatic approach to maintain mappings valid and up-to-date over time. In this article, we study variations of a specific KOS complex change (split) for two biomedical KOS (SNOMED CT and ICD-9-CM) through a rigorous method of investigation for identifying and refining complex changes, and for selecting representative cases. We empirically analyze and explain their influence on the evolution of associated mappings. Results point out the importance of considering various dimensions of the information described in KOS, like the semantic structure of concepts, the set of relevant information used to define the mappings and the change operations interfering with this set of information.

A CT-assisted method of dosimetry in brachytherapy of lung cancer

International Nuclear Information System (INIS)

Senan, S.; Lagerwaard, F.J.; Pan, C. de; Sipkema, D.; Murrer, L.H.P.; Burgers, S.A.

2000-01-01

The toxicity of endobronchial brachytherapy (EB), in particular fatal haemoptysis and bronchial wall necrosis, has been correlated with the total dose, fraction size, volume encompassed by the 100% isodose, and a proximal tumor location. We describe a CT-based planning method which, by improving target volume definition and volumeric dose information, can improve the therapeutic ratio of EB. Sixteen CT-assisted EB procedures were performed in patients who were treated with palliative high-dose rate EB. The CT data were used to analyze applicator position in relation to anatomy. An example of a three-dimensional optimized treatment plan was generated and analyzed using different types of dose-volume histograms. The procedure was well tolerated by patients and no post-procedure complications were observed. The bronchial applicator was eccentrically positioned at the level of the carina/mainstem bronchus in 12 (of 14) CT scans. A planning CT prior to EB was not found to be useful as the final target volume and/or the final applicator position were not reliably predicted before the therapeutic bronchoscopy. CT-scans performed with the applicator in situ allowed the bronchial segments in the target volume to be identified and enabled dose prescription to the bronchial mucosa. CT-assisted EB is feasible and underlines the need for using centered applicators for proximally located tumors. By enabling accurate mucosal dose prescription, CT-assisted EB may reduce the toxicity of fractionated EB in the curative setting. However, faster on-line EB treatment planning is needed for the routine clinical application of this technique. (author)

Concept and development of measurement method of time sensitivity profile (TSP) in X-ray CT. Comparison of non-helical, single-slice helical, and multi-slice helical scans

International Nuclear Information System (INIS)

Tsujioka, Katsumi; Ida, Yoshihiro; Ohtsubo, Hironori; Takahashi, Yasukata; Niwa, Masayoshi

2000-01-01

We focused on the time element contained in a single CT image, and devised the concept of a time-sensitivity profile (TSP) describing how the time element is translated into an image. We calculated the data collection time range when the helical pitch is changed in non helical scans, single slice helical scans, and multi slice helical scans. We then calculated the time sensitivity profile (TSP) from the weighting applied when the data collection time range is translated into an image. TSP was also measured for each scanning method using our self-made moving phantom. TSPs obtained from the calculation and the experiments were very close. TSP showed interesting characteristics with each scanning method, especially in the case of multi slice helical scanning, in which TSP became shorter as helical pitch increased. We referred to the TSP's FWHM as the effective scanning time. When we conducted multi slice helical scanning at helical pitch 3, the effective scanning time increased to about 24% longer than that of a non helical scan. When we conducted multi slice helical scanning at helical pitch 5 or 6, the effective scanning time was about half that of a non helical scan. The time sensitivity profile (TSP) is a totally new concept that we consider an important element in discussing the time resolution of a CT scanner. The results of this review will provide significant data in determining the scanning parameters when scanning a moving object. (author)

Detection and compensation of organ/lesion motion using 4D-PET/CT respiratory gated acquisition techniques

International Nuclear Information System (INIS)

Bettinardi, Valentino; Picchio, Maria; Di Muzio, Nadia; Gianolli, Luigi; Gilardi, Maria Carla; Messa, Cristina

2010-01-01

Purpose: To describe the degradation effects produced by respiratory organ and lesion motion on PET/CT images and to define the role of respiratory gated (RG) 4D-PET/CT techniques to compensate for such effects. Methods: Based on the literature and on our own experience, technical recommendations and clinical indications for the use of RG 4D PET/CT have been outlined. Results: RG 4D-PET/CT techniques require a state of the art PET/CT scanner, a respiratory monitoring system and dedicated acquisition and processing protocols. Patient training is particularly important to obtain a regular breathing pattern. An adequate number of phases has to be selected to balance motion compensation and statistical noise. RG 4D PET/CT motion free images may be clinically useful for tumour tissue characterization, monitoring patient treatment and target definition in radiation therapy planning. Conclusions: RG 4D PET/CT is a valuable tool to improve image quality and quantitative accuracy and to assess and measure organ and lesion motion for radiotherapy planning.

Dosimetric consequences of the shift towards computed tomography guided target definition and planning for breast conserving radiotherapy

Directory of Open Access Journals (Sweden)

Korevaar Erik W

2008-01-01

Full Text Available Abstract Background The shift from conventional two-dimensional (2D to three-dimensional (3D-conformal target definition and dose-planning seems to have introduced volumetric as well as geometric changes. The purpose of this study was to compare coverage of computed tomography (CT-based breast and boost planning target volumes (PTV, absolute volumes irradiated, and dose delivered to the organs at risk with conventional 2D and 3D-conformal breast conserving radiotherapy. Methods Twenty-five patients with left-sided breast cancer were subject of CT-guided target definition and 3D-conformal dose-planning, and conventionally defined target volumes and treatment plans were reconstructed on the planning CT. Accumulated dose-distributions were calculated for the conventional and 3D-conformal dose-plans, taking into account a prescribed dose of 50 Gy for the breast plans and 16 Gy for the boost plans. Results With conventional treatment plans, CT-based breast and boost PTVs received the intended dose in 78% and 32% of the patients, respectively, and smaller volumes received the prescribed breast and boost doses compared with 3D-conformal dose-planning. The mean lung dose, the volume of the lungs receiving > 20 Gy, the mean heart dose, and volume of the heart receiving > 30 Gy were significantly less with conventional treatment plans. Specific areas within the breast and boost PTVs systematically received a lower than intended dose with conventional treatment plans. Conclusion The shift towards CT-guided target definition and planning as the golden standard for breast conserving radiotherapy has resulted in improved target coverage at the cost of larger irradiated volumes and an increased dose delivered to organs at risk. Tissue is now included into the breast and boost target volumes that was never explicitly defined or included with conventional treatment. Therefore, a coherent definition of the breast and boost target volumes is needed, based on

Dosimetric consequences of the shift towards computed tomography guided target definition and planning for breast conserving radiotherapy

International Nuclear Information System (INIS)

Laan, Hans Paul van der; Dolsma, Wil V; Maduro, John H; Korevaar, Erik W; Langendijk, Johannes A

2008-01-01

The shift from conventional two-dimensional (2D) to three-dimensional (3D)-conformal target definition and dose-planning seems to have introduced volumetric as well as geometric changes. The purpose of this study was to compare coverage of computed tomography (CT)-based breast and boost planning target volumes (PTV), absolute volumes irradiated, and dose delivered to the organs at risk with conventional 2D and 3D-conformal breast conserving radiotherapy. Twenty-five patients with left-sided breast cancer were subject of CT-guided target definition and 3D-conformal dose-planning, and conventionally defined target volumes and treatment plans were reconstructed on the planning CT. Accumulated dose-distributions were calculated for the conventional and 3D-conformal dose-plans, taking into account a prescribed dose of 50 Gy for the breast plans and 16 Gy for the boost plans. With conventional treatment plans, CT-based breast and boost PTVs received the intended dose in 78% and 32% of the patients, respectively, and smaller volumes received the prescribed breast and boost doses compared with 3D-conformal dose-planning. The mean lung dose, the volume of the lungs receiving > 20 Gy, the mean heart dose, and volume of the heart receiving > 30 Gy were significantly less with conventional treatment plans. Specific areas within the breast and boost PTVs systematically received a lower than intended dose with conventional treatment plans. The shift towards CT-guided target definition and planning as the golden standard for breast conserving radiotherapy has resulted in improved target coverage at the cost of larger irradiated volumes and an increased dose delivered to organs at risk. Tissue is now included into the breast and boost target volumes that was never explicitly defined or included with conventional treatment. Therefore, a coherent definition of the breast and boost target volumes is needed, based on clinical data confirming tumour control probability and normal

Computed tomographic (CT) scans in cerebral palsy (CP)

International Nuclear Information System (INIS)

Kolawole, T.M.; Patel, P.J.; Mahdi, A.H.

1989-01-01

The CT findings in 120 cerebral palsied children are analysed. The 72.5% positive findings are correlated with the clinical types, as well as the aetiological basis for the cerebral palsy. The spastic type, 83.3% of the total number of children, had the highest positive findings. The yield was increased in children with seizures (91.3%) and those in the postnatal group (90%), as well as those with birth trauma and neonatal asphyxia (94%). The findings were those of atrophy in 30.8%, hydrocephalus, in 10%, infarct in 11.6%, porencephaly in 8.3% and others. The atropic changes and their patterns are explained. Treatable lesions, such as tumour, hydrocephalus, subdural haematoma, porencephaly and hygroma were identified in 22.5% of cases. It is concluded that CT scan is definitely efficacious in the management of cerebral palsied children. (orig.)

The Utility of PET/CT in the Planning of External Radiation Therapy for Prostate Cancer.

Science.gov (United States)

Calais, Jeremie; Cao, Minsong; Nickols, Nicholas G

2018-04-01

Radiotherapy and radical prostatectomy are the definitive treatment options for patients with localized prostate cancer. A rising level of prostate-specific antigen after radical prostatectomy indicates prostate cancer recurrence, and these patients may still be cured with salvage radiotherapy. To maximize chance for cure, the irradiated volumes should completely encompass the extent of disease. Therefore, accurate estimation of the location of disease is critical for radiotherapy planning in both the definitive and the salvage settings. Current first-line imaging for prostate cancer has limited sensitivity for detection of disease both at initial staging and at biochemical recurrence. Integration of PET into routine evaluation of prostate cancer patients may improve both staging accuracy and radiotherapy planning. 18 F-FDG PET/CT is now routinely used in radiation planning for several cancer types. However, 18 F-FDG PET/CT has low sensitivity for prostate cancer. Additional PET probes evaluated in prostate cancer include 18 F-sodium fluoride, 11 C-acetate, 11 C- or 18 F-choline, 18 F-fluciclovine, and 68 Ga- or 18 F-labeled ligands that bind prostate-specific membrane antigen (PSMA). PSMA ligands appear to be the most sensitive and specific but have not yet received Food and Drug Administration New Drug Application approval for use in the United States. Retrospective and prospective investigations suggest a potential major impact of PET/CT on prostate radiation treatment planning. Prospective trials randomizing patients to routine radiotherapy planning versus PET/CT-aided planning may show meaningful clinical outcomes. Prospective clinical trials evaluating the addition of 18 F-fluciclovine PET/CT for planning of salvage radiotherapy with clinical endpoints are under way. Prospective trials evaluating the clinical impact of PSMA PET/CT on prostate radiation planning are indicated. © 2018 by the Society of Nuclear Medicine and Molecular Imaging.

Correlation of CT and MR findings with clinical outcome

International Nuclear Information System (INIS)

Kim, Hak Soo; Kim, In One; Choi, Du Hwan; Yeon, Kyung Mo; Hwang, Yong Seung

1991-01-01

A retrospective analysis of the CT and MR findings of 14 pediatric patients with brain stem tumors was performed to evaluate whether the clinical outcome could be predicted from a radiographic pattern of the tumors. CT was performed in 11 patients and MR was performed in 14 patients. Ten patients were treated with radiation therapy (RT) alone, 2 patients with RT and chemotherapy, and 2 patients underwent subtotal resection. After treatment, 9 patients died within 10 months, and 5 patients were alive for 9 months to 51 months. There was no statistically significant correlation between survival and tumor location or size, but in 2 cases of exophytic growing tumor, a subtotal resection of the tumor was possible and the patients were alive for 9 months and 24 months, respectively. The tumors with a cystic portion and definite rim enhancement revealed a poor response to conventional RT, and all 6 patients died within 10 months. In conclusion, a better prognosis is predicted in the case of an exophytic growing tumor after surgical resection, but the definite ring-enhancing tumor showed a poor response on conventional RT. Also, we should consider a more active therapeutic approach such as hyperfractionated RT or combinations of chemotherapy to improve the prognosis

A Potential Tension in DSM-5: The General Definition of Mental Disorder versus Some Specific Diagnostic Criteria.

Science.gov (United States)

Amoretti, M Cristina; Lalumera, Elisabetta

2018-05-30

The general concept of mental disorder specified in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders is definitional in character: a mental disorder might be identified with a harmful dysfunction. The manual also contains the explicit claim that each individual mental disorder should meet the requirements posed by the definition. The aim of this article is two-fold. First, we shall analyze the definition of the superordinate concept of mental disorder to better understand what necessary (and sufficient) criteria actually characterize such a concept. Second, we shall consider the concepts of some individual mental disorders and show that they are in tension with the definition of the superordinate concept, taking pyromania and narcissistic personality disorder as case studies. Our main point is that an unexplained and not-operationalized dysfunction requirement that is included in the general definition, while being systematically violated by the diagnostic criteria of specific mental disorders, is a logical error. Then, either we unpack and operationalize the dysfunction requirement, and include explicit diagnostic criteria that can actually meet it, or we simply drop it.

The diagnostic value of contrast-enhanced CT in Acute bilateral renal cortical necrosis: a case report

International Nuclear Information System (INIS)

Choi, Pil Youb; Lee, Su Han; Lee, Woo Dong

1996-01-01

Acute renal cortical necrosis in which there is destruction of the renal cortex and sparing of the renal medulla, is a relatively rare cause of acute renal failure. A definitive diagnosis of acute renal cortical necrosis is based on renal biopsy, but on CT(computed tomography) the rather specific contrast-enhanced appearance of acute renal cortical necrosis has been described. As renal biopsy is not available, contrast-enhanced CT is a useful, noninvasive investigate modality for the early diagnosis of acute renal cortical necrosis. We report the characteristic CT findings of acute renal cortical necrosis in a patient with acute renal failure following an operation for abdominal trauma

Satellite Power Systems (SPS) concept definition study, exhibit C. Volume 2, part 2: System engineering, cost and programmatics

Science.gov (United States)

Hanley, G. M.

1979-01-01

Volume 2, Part 2, of a seven volume Satellite Power Systems (SPS) report is presented. Part 2 covers cost and programmatics and is divided into four sections. The first section gives illustrations of the SPS reference satellite and rectenna concept, and an overall scenario for SPS space transportation involvement. The second section presents SPS program plans for the implementation of PHASE C/D activities. These plans describe SPS program schedules and networks, critical items of systems evolution/technology development, and the natural resources analysis. The fourth section presents summary comments on the methods and rationale followed in arriving at the results documented. Suggestions are also provided in those areas where further analysis or evaluation will enhance SPS cost and programmatic definitions.

Spiritual nursing care: A concept analysis

Directory of Open Access Journals (Sweden)

Lydia V. Monareng

2012-10-01

Full Text Available Although the concept ‘spiritual nursing care’ has its roots in the history of the nursing profession, many nurses in practice have difficulty integrating the concept into practice. There is an ongoing debate in the empirical literature about its definition, clarity and application in nursing practice. The study aimed to develop an operational definition of the concept and its application in clinical practice. A qualitative study was conducted to explore and describe how professional nurses render spiritual nursing care. A purposive sampling method was used to recruit the sample. Individual and focus group interviews were audio-taped and transcribed verbatim. Trustworthiness was ensured through strategies of truth value, applicability, consistency and neutrality. Data were analysed using the NUD*IST power version 4 software, constant comparison, open, axial and selective coding. Tech’s eight steps of analysis were also used, which led to the emergence of themes, categories and sub-categories. Concept analysis was conducted through a comprehensive literature review and as a result ‘caring presence’ was identified as the core variable from which all the other characteristics of spiritual nursing care arise. An operational definition of spiritual nursing care based on the findings was that humane care is demonstrated by showing caring presence, respect and concern for meeting the needs not only of the body and mind of patients, but also their spiritual needs of hope and meaning in the midst of health crisis, which demand equal attention for optimal care from both religious and nonreligious nurses.

Is Social Capital a Good Concept?

DEFF Research Database (Denmark)

Bjørnskov, Christian; Sønderskov, Kim Mannemar

The aim of this paper is to explore whether the concept of social capital as popularized by Robert Putnam is a good social science concept. Taken Gerring’s and Adcock and Collier’s work on concept formation and measurement validity as the starting point, the paper first discusses necessary...... conditions for concepts to be good in a strict sense. Afterwards, an empirical section explores the validity of the unidimensionality assumption of most definitions of social capital. This assumption is rejected in four separate tests at both the micro and macro level. A final section therefore discusses...

Concept analysis of culture applied to nursing.

Science.gov (United States)

Marzilli, Colleen

2014-01-01

Culture is an important concept, especially when applied to nursing. A concept analysis of culture is essential to understanding the meaning of the word. This article applies Rodgers' (2000) concept analysis template and provides a definition of the word culture as it applies to nursing practice. This article supplies examples of the concept of culture to aid the reader in understanding its application to nursing and includes a case study demonstrating components of culture that must be respected and included when providing health care.

Implications of Artefacts Reduction in the Planning CT Originating from Implanted Fiducial Markers

International Nuclear Information System (INIS)

Kassim, Iskandar; Joosten, Hans; Barnhoorn, Jaco C.; Heijmen, Ben J.M.; Dirkx, Maarten L.P.

2011-01-01

The efficacy of metal artefact reduction (MAR) software to suppress artefacts in reconstructed computed tomography (CT) images originating from small metal objects, like tumor markers and surgical clips, was evaluated. In addition, possible implications of using digital reconstructed radiographs (DRRs), based on the MAR CT images, for setup verification were analyzed. A phantom and 15 patients with different tumor sites and implanted markers were imaged with a multislice CT scanner. The raw image data was reconstructed both with the clinically used filtered-backprojection (FBP) and with the MAR software. Using the MAR software, improvements in image quality were often observed in CT slices with markers or clips. Especially when several markers were located near to each other, fewer streak artefacts were observed than with the FBP algorithm. In addition, the shape and size of markers could be identified more accurately, reducing the contoured marker volumes by a factor of 2. For the phantom study, the CT numbers measured near to the markers corresponded more closely to the expected values. However, the MAR images were slightly more smoothed compared with the images reconstructed with FBP. For 8 prostate cancer patients in this study, the interobserver variation in 3D marker definition was similar (<0.4 mm) when using DRRs based on either FBP or MAR CT scans. Automatic marker matches also showed a similar success rate. However, differences in automatic match results up to 1 mm, caused by differences in the marker definition, were observed, which turned out to be (borderline) statistically significant (p = 0.06) for 2 patients. In conclusion, the MAR software might improve image quality by suppressing metal artefacts, probably allowing for a more reliable delineation of structures. When implanted markers or clips are used for setup verification, the accuracy may slightly be improved as well, which is relevant when using very tight clinical target volume (CTV) to

Normal CT characteristics of the thymus in adults

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Simanovsky, Natalia, E-mail: natalias@hadassah.org.il [Department of Medical Imaging, Hadassah - Hebrew University Medical Center, Jerusalem (Israel); Hiller, Nurith; Loubashevsky, Natali; Rozovsky, Katya [Department of Medical Imaging, Hadassah - Hebrew University Medical Center, Jerusalem (Israel)

2012-11-15

Background: The thymus changes with age. Its shape and the proportion of solid tissue and fat vary between individuals, yet there is no comprehensive work describing the size and morphology of the normal thymus on CT. As a result, many adults with some preserved soft tissue in the thymus may undergo extensive work-up to exclude mediastinal tumor. Our aim was to quantify CT characteristics of the normal thymus in an adult population. Methods: CT chest scans of 194 trauma patients aged 14-78 years (mean 52.6 years), were retrospectively reviewed. The density, volume, shape and predominant side of the thymus were recorded for 56 patients in whom some solid tissue was preserved. Statistical analysis of these characteristics according to the patient age and gender was performed. Results: Thymic density and volume decreased progressively with age. No solid tissue component was seen in the thymus in patients older than 54 years. In the majority of patients, the thymus had an arrowhead shape, with middle position. However, great variability in thymic shape and border were noted. There was a highly significant relationship between density and patient age (p < 0.0001). Conclusion: We hope that our work will help in the definition of normal thymic CT parameters in adults, help to prevent unnecessary and expensive imaging procedures, and reduce patient exposure to ionizing radiation.

Normal CT characteristics of the thymus in adults

International Nuclear Information System (INIS)

Simanovsky, Natalia; Hiller, Nurith; Loubashevsky, Natali; Rozovsky, Katya

2012-01-01

Background: The thymus changes with age. Its shape and the proportion of solid tissue and fat vary between individuals, yet there is no comprehensive work describing the size and morphology of the normal thymus on CT. As a result, many adults with some preserved soft tissue in the thymus may undergo extensive work-up to exclude mediastinal tumor. Our aim was to quantify CT characteristics of the normal thymus in an adult population. Methods: CT chest scans of 194 trauma patients aged 14–78 years (mean 52.6 years), were retrospectively reviewed. The density, volume, shape and predominant side of the thymus were recorded for 56 patients in whom some solid tissue was preserved. Statistical analysis of these characteristics according to the patient age and gender was performed. Results: Thymic density and volume decreased progressively with age. No solid tissue component was seen in the thymus in patients older than 54 years. In the majority of patients, the thymus had an arrowhead shape, with middle position. However, great variability in thymic shape and border were noted. There was a highly significant relationship between density and patient age (p < 0.0001). Conclusion: We hope that our work will help in the definition of normal thymic CT parameters in adults, help to prevent unnecessary and expensive imaging procedures, and reduce patient exposure to ionizing radiation.

A concept analysis of professional commitment in nursing.

Science.gov (United States)

García-Moyano, Loreto; Altisent, Rogelio; Pellicer-García, Begoña; Guerrero-Portillo, Sandra; Arrazola-Alberdi, Oihana; Delgado-Marroquín, María Teresa

2017-01-01

The concept of professional commitment is being widely studied at present. However, although it is considered an indicator for the most human part of nursing care, there is no clear definition for it, and different descriptors are being used indiscriminately to reference it. The aim of this study is to clarify the concept of professional commitment in nursing through the Rodgers' evolutionary concept analysis process. Systematic search using English and Spanish descriptors and concept analysis. Studies published between 2009 and June 2015, front-to-back analysis of the Nursing Ethics journal and manual check of articles cited in studies related to the Nijmegen Professionalism Scale. The procedure of concept analysis developed by Rodgers was used. Ethical considerations: Although the topic was not labeled as sensitive and subject to ethical approval, its realization was approved by the Ethical Committee of Clinical Research of Aragon (CEICA) approved the study on 18 March 2015 and also careful procedures have been followed according to ethics expressed in the Declaration of Helsinki. A total of 17 published studies. A clear definition of the concept was made, and surrogate terms, concept dimension, differential factors related to the concept, sociocultural variations and consequences for nursing practice were identified. There is a need for continuous advancement in the development of the concept, specific actions to encourage this and the improvement of evaluation methods for its study.

Clinical Application of colored three-dimensional CT (3D-CT) for brain tumors using helical scanning CT (HES-CT)

International Nuclear Information System (INIS)

Ogura, Yuko; Katada, Kazuhiro; Fujisawa, Kazuhisa; Imai, Fumihiro; Kawase, Tsukasa; Kamei, Yoshifumi; Kanno, Tetsuo; Takeshita, Gen; Koga, Sukehiko

1995-01-01

We applied colored three-dimensional CT (colored 3D-CT) images to distinguish brain tumors from the surrounding vascular and bony structures using a work station system and helical scanning CT (HES-CT). CT scanners with a slip-ring system were employed (TCT-900S and X vigor). A slice thickness of 2 mm and bed speed of 2 mm/s were used. The volume of contrast medium injected was 60 to 70 ml. Four to 8 colors were used for the tissue segmentation on the workstation system (xtension) using the data transferred from HES-CT. Tissue segmentation succeeded on the colored 3D-CT images in all 13 cases. The relationship between the tumors and the surrounding structures were easily recognized. The technique was useful to simulate operative fields, because deep structures could be visualized by cutting and drilling the colored 3D-CT volumetric data. On the basis of our findings, we suggest that colored 3D-CT images should be used as a supplementary aid for preoperative simulation. (author)

Facilitation of self-empowerment of women living with borderline personality disorder: A concept analysis

Directory of Open Access Journals (Sweden)

N. Ntshingila

2016-10-01

Objective: : The objective is to define the central concept of “facilitation of self empowerment”. Method: Analysis and synthesis reasoning methods as indicated by Walker and Avant (2011 were used to define the central concept. Results: A definition of the concept “facilitation of self-empowerment” was formulated from the dictionary and subject definitions. Conclusion: The central concept is important for developing a model as a frame of reference to assist psychiatric nurse practitioners in facilitating the mental health of women living with borderline personality disorder.

Definition of gross tumor volume in lung cancer: inter-observer variability

NARCIS (Netherlands)

van de Steene, Jan; Linthout, Nadine; de Mey, Johan; Vinh-Hung, Vincent; Claassens, Cornelia; Noppen, Marc; Bel, Arjan; Storme, Guy

2002-01-01

BACKGROUND AND PURPOSE: To determine the inter-observer variation in gross tumor volume (GTV) definition in lung cancer, and its clinical relevance. MATERIALS AND METHODS: Five clinicians involved in lung cancer were asked to define GTV on the planning CT scan of eight patients. Resulting GTVs were

What is mental health? Evidence towards a new definition from a mixed methods multidisciplinary international survey

Science.gov (United States)

Manwell, Laurie A; Barbic, Skye P; Roberts, Karen; Durisko, Zachary; Lee, Cheolsoon; Ware, Emma; McKenzie, Kwame

2015-01-01

Objective Lack of consensus on the definition of mental health has implications for research, policy and practice. This study aims to start an international, interdisciplinary and inclusive dialogue to answer the question: What are the core concepts of mental health? Design and participants 50 people with expertise in the field of mental health from 8 countries completed an online survey. They identified the extent to which 4 current definitions were adequate and what the core concepts of mental health were. A qualitative thematic analysis was conducted of their responses. The results were validated at a consensus meeting of 58 clinicians, researchers and people with lived experience. Results 46% of respondents rated the Public Health Agency of Canada (PHAC, 2006) definition as the most preferred, 30% stated that none of the 4 definitions were satisfactory and only 20% said the WHO (2001) definition was their preferred choice. The least preferred definition of mental health was the general definition of health adapted from Huber et al (2011). The core concepts of mental health were highly varied and reflected different processes people used to answer the question. These processes included the overarching perspective or point of reference of respondents (positionality), the frameworks used to describe the core concepts (paradigms, theories and models), and the way social and environmental factors were considered to act. The core concepts of mental health identified were mainly individual and functional, in that they related to the ability or capacity of a person to effectively deal with or change his/her environment. A preliminary model for the processes used to conceptualise mental health is presented. Conclusions Answers to the question, ‘What are the core concepts of mental health?’ are highly dependent on the empirical frame used. Understanding these empirical frames is key to developing a useful consensus definition for diverse populations. PMID:26038353

A One-Step Cone-Beam CT-Enabled Planning-to-Treatment Model for Palliative Radiotherapy-From Development to Implementation

Energy Technology Data Exchange (ETDEWEB)

Wong, Rebecca K.S., E-mail: rebecca.wong@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Letourneau, Daniel; Varma, Anita [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Bissonnette, Jean Pierre; Fitzpatrick, David; Grabarz, Daniel; Elder, Christine [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Martin, Melanie; Bezjak, Andrea [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Panzarella, Tony [Department of Biostatistics, Princess Margaret Hospital, Toronto, Ontario (Canada); Gospodarowicz, Mary [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Hospital, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada)

2012-11-01

Purpose: To develop a cone-beam computed tomography (CT)-enabled one-step simulation-to-treatment process for the treatment of bone metastases. Methods and Materials: A three-phase prospective study was conducted. Patients requiring palliative radiotherapy to the spine, mediastinum, or abdomen/pelvis suitable for treatment with simple beam geometry ({<=}2 beams) were accrued. Phase A established the accuracy of cone-beam CT images for the purpose of gross tumor target volume (GTV) definition. Phase B evaluated the feasibility of implementing the cone-beam CT-enabled planning process at the treatment unit. Phase C evaluated the online cone-beam CT-enabled process for the planning and treatment of patients requiring radiotherapy for bone metastases. Results: Eighty-four patients participated in this study. Phase A (n = 9) established the adequacy of cone-beam CT images for target definition. Phase B (n = 45) established the quality of treatment plans to be adequate for clinical implementation for bone metastases. When the process was applied clinically in bone metastases (Phase C), the degree of overlap between planning computed tomography (PCT) and cone-beam CT for GTV and between PCT and cone-beam CT for treatment field was 82% {+-} 11% and 97% {+-} 4%, respectively. The oncologist's decision to accept the plan under a time-pressured environment remained of high quality, with the cone-beam CT-generated treatment plan delivering at least 90% of the prescribed dose to 100% {+-} 0% of the cone-beam CT planning target volume (PTV). With the assumption that the PCT PTV is the gold-standard target, the cone-beam CT-generated treatment plan delivered at least 90% and at least 95% of dose to 98% {+-} 2% and 97% {+-} 5% of the PCT PTV, respectively. The mean time for the online planning and treatment process was 32.7 {+-} 4.0 minutes. Patient satisfaction was high, with a trend for superior satisfaction with the cone-beam CT-enabled process. Conclusions: The cone

Transforming care in nursing: a concept analysis.

Science.gov (United States)

Vázquez-Calatayud, Mónica; Oroviogoicoechea, Cristina; Saracibar, Maribel; Pumar-Méndez, María J

2017-04-01

Although the concept of 'Transforming care' is promising for improving health care, there is no consensus in the field as to its definition. The aim of this concept analysis is to develop a deeper understanding of the term 'Transforming care' within the nursing discipline, in order to facilitate its comprehension, implementation, and evaluation. We performed a comprehensive literature review on electronic databases such as Medline (PubMed), Cinahl (Ebsco), Cochrane Library, PsycINFO (Ovid), Web of Science, Wiley-Blackwell, ScienceDirect, and SpringerLink and used Walker and Avant's approach to analyse the concept. From the 20 studies selected for this analysis, 3 main attributes of 'Transforming care' were identified: patient-centredness, evidence-based change, and transformational leadership driven. We suggest an operational definition to facilitate the implementation of the concept in practice. Furthermore, we propose that implementation is guided by the following key ideas: (1) fostering a culture of continuous improvement; (2) encouraging bottom-up initiatives; (3) promoting patient-centred care; and (4) using transformational leadership. Lastly, the evaluation of 'Transforming care' initiatives should assess care processes and professionals' and patients' outcomes.

[Concept, definition and classification of intra-abdominal hypertension in pregnancy].

Science.gov (United States)

Marshalov, D V; Salov, I A; Shifman, E M; Petrenko, A P

2013-01-01

The article stresses methodological aspects of intaabdominal hypertension at pregnancy. Formal-logical analysis of conceptual framework and available classifications of intaabdominal hypertension was carried out. The article presents new definition and classification of intaabdominal hypertension.

Bubble-like appearances are characteristic thin-section CT findings of adenocarcinoma

International Nuclear Information System (INIS)

Kojima, Yoko; Saito, Haruhiro; Ito, Hiroyuki

2008-01-01

Adenocarcinomas are often diagnosed as old inflammatory lesions which are sometimes overlooked. Some of these adenocarcinomas display characteristic thin-section computed tomography (TS-CT) findings. We reported on these bubble-like appearances (BLA). We studied the BLA characteristics of adenocarcinomas. We reviewed the TS-CT findings of 17 (6 men, 11 women) cases of adenocarcinoma with bubble-like appearances. All 17 patients had undergone surgery between August 2003 and March 2007. We studied correlations between the TS-CT findings, the pathological findings and the clinical characteristics. The average tumor diameter was 35.4 mm. The definition of BLA is; having a irregular shape with straight margins, peripheral ground-glass opacity (GGO), dilated air bronchograms (more than 3), prominent pleural indentation. The pathological characteristics of tumors with BLA were; peripheral bronchioloalveolar cell carcinoma (BAC) patterns, almost total collapse (about 80% of the tumor area), and several ectatic small bronchi. Six cases were initially overlooked, because the TS-CT findings appeared as old inflammation. The average tumor doubling time was 1167 days. After resection, there have been no recurrences. On TS-CT images, BLA type adenocarcinomas appear as irregular in shape and they have a very slow doubling time. These types of lesions require careful attention because they are often diagnosed as old inflammatory scarring. (author)

Ultra-low dose CT attenuation correction for PET/CT

International Nuclear Information System (INIS)

Xia Ting; Kinahan, Paul E; Alessio, Adam M; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren

2012-01-01

A challenge for positron emission tomography/computed tomography (PET/CT) quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently available, lowest dose CT techniques, extended duration cine CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging. (paper)

Ultra-low dose CT attenuation correction for PET/CT

Science.gov (United States)

Xia, Ting; Alessio, Adam M.; De Man, Bruno; Manjeshwar, Ravindra; Asma, Evren; Kinahan, Paul E.

2012-01-01

A challenge for PET/CT quantitation is patient respiratory motion, which can cause an underestimation of lesion activity uptake and an overestimation of lesion volume. Several respiratory motion correction methods benefit from longer duration CT scans that are phase matched with PET scans. However, even with the currently-available, lowest dose CT techniques, extended duration CINE CT scans impart a substantially high radiation dose. This study evaluates methods designed to reduce CT radiation dose in PET/CT scanning. Methods We investigated selected combinations of dose reduced acquisition and noise suppression methods that take advantage of the reduced requirement of CT for PET attenuation correction (AC). These include reducing CT tube current, optimizing CT tube voltage, adding filtration, CT sinogram smoothing and clipping. We explored the impact of these methods on PET quantitation via simulations on different digital phantoms. Results CT tube current can be reduced much lower for AC than that in low dose CT protocols. Spectra that are higher energy and narrower are generally more dose efficient with respect to PET image quality. Sinogram smoothing could be used to compensate for the increased noise and artifacts at radiation dose reduced CT images, which allows for a further reduction of CT dose with no penalty for PET image quantitation. Conclusion When CT is not used for diagnostic and anatomical localization purposes, we showed that ultra-low dose CT for PET/CT is feasible. The significant dose reduction strategies proposed here could enable respiratory motion compensation methods that require extended duration CT scans and reduce radiation exposure in general for all PET/CT imaging. PMID:22156174

The GOSTT concept and hybrid mixed/virtual/augmented reality environment radioguided surgery

International Nuclear Information System (INIS)

Valdés Olmos, R. A.; Van Leeuwen, F. W. B.; Vidal-Sicart, S.; Giammarile, F.; Zaknun, J. J.; Mariani, G.

2014-01-01

The popularity gained by the sentinel lymph node (SLN) procedure in the last two decades did increase the interest of the surgical disciplines for other applications of radioguided surgery. An example is the gamma-probe guided localization of occult or difficult to locate neoplastic lesions. Such guidance can be achieved by intralesional delivery (ultrasound, stereotaxis or CT) of a radiolabelled agent that remains accumulated at the site of the injection. Another possibility rested on the use of systemic administration of a tumour-seeking radiopharmaceutical with favourable tumour accumulation and retention. On the other hand, new intraoperative imaging devices for radioguided surgery in complex anatomical areas became available. All this a few years ago led to the delineation of the concept Guided intraOperative Scintigraphic Tumour Targeting (GOSTT) to include the whole spectrum of basic and advanced nuclear medicine procedures required for providing a roadmap that would optimise surgery. The introduction of allied signatures using, e.g. hybrid tracers for simultaneous detection of the radioactive and fluorescent signals did amply the GOSTT concept. It was now possible to combine perioperative nuclear medicine imaging with the superior resolution of additional optical guidance in the operating room. This hybrid approach is currently in progress and probably will become an important model to follow in the coming years. A cornerstone in the GOSTT concept is constituted by diagnostic imaging technologies like SPECT/CT. SPECT/CT was introduced halfway the past decade and was immediately incorporated into the SLN procedure. Important reasons attributing to the success of SPECT/CT were its combination with lymphoscintigraphy, and the ability to display SLNs in an anatomical environment. This latter aspect has significantly been improved in the new generation of SPECT/CT cameras and provides the base for the novel mixed reality protocols of image-guided surgery. In

The GOSTT concept and hybrid mixed/virtual/augmented reality environment radioguided surgery.

Science.gov (United States)

Valdés Olmos, R A; Vidal-Sicart, S; Giammarile, F; Zaknun, J J; Van Leeuwen, F W; Mariani, G

2014-06-01

The popularity gained by the sentinel lymph node (SLN) procedure in the last two decades did increase the interest of the surgical disciplines for other applications of radioguided surgery. An example is the gamma-probe guided localization of occult or difficult to locate neoplastic lesions. Such guidance can be achieved by intralesional delivery (ultrasound, stereotaxis or CT) of a radiolabelled agent that remains accumulated at the site of the injection. Another possibility rested on the use of systemic administration of a tumour-seeking radiopharmaceutical with favourable tumour accumulation and retention. On the other hand, new intraoperative imaging devices for radioguided surgery in complex anatomical areas became available. All this a few years ago led to the delineation of the concept Guided intraOperative Scintigraphic Tumour Targeting (GOSTT) to include the whole spectrum of basic and advanced nuclear medicine procedures required for providing a roadmap that would optimise surgery. The introduction of allied signatures using, e.g. hybrid tracers for simultaneous detection of the radioactive and fluorescent signals did amply the GOSTT concept. It was now possible to combine perioperative nuclear medicine imaging with the superior resolution of additional optical guidance in the operating room. This hybrid approach is currently in progress and probably will become an important model to follow in the coming years. A cornerstone in the GOSTT concept is constituted by diagnostic imaging technologies like SPECT/CT. SPECT/CT was introduced halfway the past decade and was immediately incorporated into the SLN procedure. Important reasons attributing to the success of SPECT/CT were its combination with lymphoscintigraphy, and the ability to display SLNs in an anatomical environment. This latter aspect has significantly been improved in the new generation of SPECT/CT cameras and provides the base for the novel mixed reality protocols of image-guided surgery. In

Development of planar CT system for multi-layer PCB inspection

Energy Technology Data Exchange (ETDEWEB)

Kim, Seung Ho; Youn, Hanbean; Kam, Soohwa; Park, Eunpyeong; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of)

2015-05-15

X-ray defect inspection apparatus can be used in the production line to inspect the PCB. However, a simple X-ray radiography cannot discriminate defects from the multi-layer PCBs because the layers of them overlays the defects. To complement this issue, computed tomography (CT) technology is applied to the NDT system which can offer 3-dimensional information of object. However, CT requires hundreds of projection images to examine a single PCB, hence real-time inspection is nearly impossible. In this study, we develop a planar computed tomography (pCT) system appropriate for the multi-layer PCB inspection. For the image reconstruction of planar cross-section images, we use the digital tomosynthesis (DTS) concept in association with the limited angle scanning. and performance characterization of the pCT system for the PCB inspection. The 3-d Fourier characteristics and more quantitative performance, such as contrast, uniformity, depth resolution will be presented. The cross-sectional images of multi-layer PCBs will also be demonstrated.

First-in-Human PET/CT Imaging of Metastatic Neuroendocrine Neoplasms with Cyclotron-Produced 44Sc-DOTATOC: A Proof-of-Concept Study.

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Singh, Aviral; van der Meulen, Nicholas P; Müller, Cristina; Klette, Ingo; Kulkarni, Harshad R; Türler, Andreas; Schibli, Roger; Baum, Richard P

2017-05-01

44 Sc is a promising positron emission tomography (PET) radionuclide (T 1/2  = 4.04 hours, E β+average  = 632 keV) and can be made available, using a cyclotron production route, in substantial quantities as a highly pure product. Herein, the authors report on a first-in-human PET/CT study using 44 Sc-DOTATOC prepared with cyclotron-produced 44 Sc. The production of 44 Sc was carried out through the 44 Ca(p,n) 44 Sc nuclear reaction at Paul Scherrer Institut, Switzerland. After separation, 44 Sc was shipped to Zentralklinik Bad Berka, Germany, where radiolabeling was performed, yielding radiochemically pure 44 Sc-DOTATOC. Two patients, currently followed up after peptide receptor radionuclide therapy of metastatic neuroendocrine neoplasms, participated in this proof-of-concept study. Blood sampling was performed before and after application of 44 Sc-DOTATOC. PET/CT acquisitions, performed at different time points after injection of 44 Sc-DOTATOC, allowed detection of even very small lesions on delayed scans. No clinical adverse effects were observed and the laboratory hematological, renal, and hepatic profiles remained unchanged. In this study, cyclotron-produced 44 Sc was used in the clinic for the first time. It is attractive for theranostic application with 177 Lu, 90 Y, or 47 Sc as therapeutic counterparts. 44 Sc-based radiopharmaceuticals will be of particular value for PET facilities without radiopharmacy, to which they can be shipped from a centralized production site.

CT determinants of prognosis in pancreatic carcinoma

International Nuclear Information System (INIS)

Schreiber, A.E.; Honda, H.; Berbaum, K.; Franken, E.A.; Lu, C.H.

1988-01-01

Abdominal CT scans of 61 patients with pathologically proved pancreatic carcinoma were analyzed to determine the radiographic features that predict length of survival. Excluded from study were patients who underwent definitive surgical procedures (Whipple procedure or pancreatectomy) or who received radiation or chemotherapy. Scans were evaluated in 18 radiographic and clinicopathologic categories. Multifactorial regression analysis indicated that the factors that most accurately predict the length of patient survival are (1) size, (2) associated lymphadenopathy, (3) hepatic metastasis, (4) hepatoduodenal ligament involvement, and (5) involvement of the mesentery and/or peritoneum

Clinical application of gated CT and dynamic CT

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Ishikawa, T; Oyama, Y; Ashida, H; Uji, T [Saint Marianna Univ., Kawasaki, Kanagawa (Japan). School of Medicine

1980-03-01

Gated CT and dynamic CT were outlined. Experiences of portal hypertension accompanied by venous mass in posterior mediastinum and the usefulness of dynamic CT for this disease were described. Gated CT of the heart could visualize intracardiac structures and morphological abnormalities by improving technique of post-data-aquisition correlation. Changes with time in CT images of normal kidneys were discussed on patients whose unilateral or bilateral kidneys were thought to be normal and who had received dynamic scan. Dynamic scan could visualize well blood circulation and mechanism of urine excretion in the kidney, which suggests a possibility of CT to detect not only morphological abnormalities but also functional disturbance of the kidney. The effectiveness of conventional CT study might be promoted in dynamic CT of the head.

CT of multiple sclerosis: reassessment of delayed scanning with high doses of contrast material

International Nuclear Information System (INIS)

Spiegel, S.M.; Vinuela, F.; Fox, A.J.; Pelz, D.M.

1985-01-01

A prospective study involving 87 patients was carried out to evaluate the necessity for a high dose of contrast material in addition to delayed computed tomographic (CT) scanning for optimal detection of the lesions of multiple sclerosis in the brain. In patients with either clinically definite multiple sclerosis or laboratory-supported definite multiple sclerosis, CT scans were obtained with a uniform protocol. Lesions consistent with multiple sclerosis were demonstrated on the second scan in 54 patients. In 36 of these 54 patients, the high-dose delayed scan added information. These results are quite similar to those of a previous study from this institution using different patients, in whom the second scan was obtained immediately after the bolus injection of contrast material containing 40 g of organically bound iodine. The lack of real difference in the results of the two studies indicate that the increased dose, not just the delay in scanning, is necessary for a proper study

Characteristics of images of angiographically proven normal coronary arteries acquired by adenosine-stress thallium-201 myocardial perfusion SPECT/CT-IQ[Symbol: see text]SPECT with CT attenuation correction changed stepwise.

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Takahashi, Teruyuki; Tanaka, Haruki; Kozono, Nami; Tanakamaru, Yoshiki; Idei, Naomi; Ohashi, Norihiko; Ohtsubo, Hideki; Okada, Takenori; Yasunobu, Yuji; Kaseda, Shunichi

2015-04-01

Although several studies have shown the diagnostic and prognostic value of CT-based attenuation correction (AC) of single photon emission computed tomography (SPECT) images for diagnosing coronary artery disease (CAD), this issue remains a matter of debate. To clarify the characteristics of CT-AC SPECT images that might potentially improve diagnostic performance, we analyzed images acquired using adenosine-stress thallium-201 myocardial perfusion SPECT/CT equipped with IQ[Symbol: see text]SPECT (SPECT/CT-IQ[Symbol: see text]SPECT) from patients with angiographically proven normal coronary arteries after changing the CT attenuation correction (CT-AC) in a stepwise manner. We enrolled 72 patients (Male 36, Female 36) with normal coronary arteries according to findings of invasive coronary angiography or CT-angiography within three months after a SPECT/CT study. Projection images were reconstructed at CT-AC values of (-), 40, 60, 80 and 100 % using a CT number conversion program according to our definition and analyzed using polar maps according to sex. CT attenuation corrected segments were located from the mid- and apical-inferior spread through the mid- and apical-septal regions and finally to the basal-anterior and basal- and mid-lateral regions in males, and from the mid-inferior region through the mid-septal and mid-anterior, and mid-lateral regions in females as the CT-AC values increased. Segments with maximal mean counts shifted from the apical-anterior to mid-anterolateral region under both stress and rest conditions in males, whereas such segments shifted from the apical-septal to the mid-anteroseptal region under both stress and rest conditions in females. We clarified which part of the myocardium and to which degree CT-AC affects it in adenosine-stress thallium-201 myocardial perfusion SPECT/CT-IQ[Symbol: see text]SPECT images by changing the CT-AC value stepwise. We also identified sex-specific shifts of segments with maximal mean counts that changed as

A case study of analyzing student teachers' concept images of the ...

African Journals Online (AJOL)

Administrator

Key words: Definite integral, concept images, process conceptions, object .... led me to conceive a three dimensional matrix with process-object layers in rows, ...... Conference on Psychology of Mathematics Education, Norwich. ... On the Dual Nature of Mathematical Conceptions: Reflections on Processes and Objects as.

On the meaning and use of the risk appetite concept.

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Aven, Terje

2013-03-01

The risk appetite concept has been given considerable attention recently in enterprise risk management contexts. A number of definitions exist, most with a link to risk acceptability, but also values and goals. The usefulness of the concept is, however, disputed; some authors argue that we can in fact do better without it. In this article, we provide a thorough discussion of what the risk appetite concept is actually trying to express and how it best can be used in the relevant decision making. The main purposes of the article are (i) to argue that the risk appetite concept, suitably interpreted, has a role to play in risk management, (ii) to show that the risk appetite concept is well supported by some types of risk perspectives and not by others, and (iii) to show how the risk appetite concept is linked to other related concepts, such as risk seeking and risk acceptability. The risk perspectives studied range from expected value and probability based definitions of risk to views on risk, that are founded on uncertainties. © 2012 Society for Risk Analysis.

[68Ga]-DOTATOC-PET/CT for meningioma IMRT treatment planning

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Bamberg Michael

2009-11-01

Full Text Available Abstract Purpose The observation that human meningioma cells strongly express somatostatin receptor (SSTR 2 was the rationale to analyze retrospectively in how far DOTATOC PET/CT is helpful to improve target volume delineation for intensity modulated radiotherapy (IMRT. Patients and Methods In 26 consecutive patients with preferentially skull base meningioma, diagnostic magnetic resonance imaging (MRI and planning-computed tomography (CT was complemented with data from [68Ga]-DOTA-D Phe1-Tyr3-Octreotide (DOTATOC-PET/CT. Image fusion of PET/CT, diagnostic computed tomography, MRI and radiotherapy planning CT as well as target volume delineation was performed with OTP-Masterplan®. Initial gross tumor volume (GTV definition was based on MRI data only and was secondarily complemented with DOTATOC-PET information. Irradiation was performed as EUD based IMRT, using the Hyperion Software package. Results The integration of the DOTATOC data led to additional information concerning tumor extension in 17 of 26 patients (65%. There were major changes of the clinical target volume (CTV which modify the PTV in 14 patients, minor changes were realized in 3 patients. Overall the GTV-MRI/CT was larger than the GTV-PET in 10 patients (38%, smaller in 13 patients (50% and almost the same in 3 patients (12%. Most of the adaptations were performed in close vicinity to bony skull base structures or after complex surgery. Median GTV based on MRI was 18.1 cc, based on PET 25.3 cc and subsequently the CTV was 37.4 cc. Radiation planning and treatment of the DOTATOC-adapted volumes was feasible. Conclusion DOTATOC-PET/CT information may strongly complement patho-anatomical data from MRI and CT in cases with complex meningioma and is thus helpful for improved target volume delineation especially for skull base manifestations and recurrent disease after surgery.

State of the science of maternal-infant bonding: a principle-based concept analysis.

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Bicking Kinsey, Cara; Hupcey, Judith E

2013-12-01

to provide a principle-based analysis of the concept of maternal-infant bonding. principle-based method of concept analysis for which the data set included 44 articles published in the last decade from Pubmed, CINAHL, and PyschINFO/PsychARTICLES. literature inclusion criteria were English language, articles published in the last decade, peer-reviewed journal articles and commentary on published work, and human populations. after a brief review of the history of maternal-infant bonding, a principle-based concept analysis was completed to examine the state of the science with regard to this concept. The concept was critically examined according to the clarity of definition (epistemological principle), applicability of the concept (pragmatic principle), consistency in use and meaning (linguistic principle), and differentiation of the concept from related concepts (logical principle). Analysis of the concept revealed: (1) Maternal-infant bonding describes maternal feelings and emotions towards her infant. Evidence that the concept encompasses behavioural or biological components was limited. (2) The concept is clearly operationalised in the affective domain. (3) Maternal-infant bonding is linguistically confused with attachment, although the boundaries between the concepts are clearly delineated. despite widespread use of the concept, maternal-infant bonding is at times superficially developed and subject to confusion with related concepts. Concept clarification is warranted. A theoretical definition of the concept of maternal-infant bonding was developed to aid in the clarification, but more research is necessary to further clarify and advance the concept. nurse midwives and other practitioners should use the theoretical definition of maternal-infant bonding as a preliminary guide to identification and understanding of the concept in clinical practice. Copyright © 2013 Elsevier Ltd. All rights reserved.

Prebiotics: why definitions matter

Science.gov (United States)

Hutkins, Robert W; Krumbeck, Janina A; Bindels, Laure B; Cani, Patrice D; Fahey, George; Goh, Yong Jun; Hamaker, Bruce; Martens, Eric C; Mills, David A; Rastal, Robert A; Vaughan, Elaine; Sanders, Mary Ellen

2015-01-01

The prebiotic concept was introduced twenty years ago, and despite several revisions to the original definition, the scientific community has continued to debate what it means to be a prebiotic. How prebiotics are defined is important not only for the scientific community, but also for regulatory agencies, the food industry, consumers and healthcare professionals. Recent developments in community-wide sequencing and glycomics have revealed that more complex interactions occur between putative prebiotic substrates and the gut microbiota than previously considered. A consensus among scientists on the most appropriate definition of a prebiotic is necessary to enable continued use of the term. PMID:26431716

CT, MRI, and FDG-PET/CT imaging findings of abdominopelvic desmoplastic small round cell tumors: Correlation with histopathologic findings

International Nuclear Information System (INIS)

Zhang Weidong; Li Chuanxing; Liu Qingyu; Hu Yingying; Cao Yun; Huang Jinhua

2011-01-01

Objective: To analyze computed tomography (CT), magnetic resonance imaging (MRI), and fluorodeoxyglucose-positron emission tomography (FDG-PET)/CT imaging features of abdominopelvic desmoplastic small round cell tumor (DSRCT) and to improve the diagnostic efficacy of these techniques for the detection of such tumor. Methods: We retrospectively analyzed 7 cases of abdominopelvic DSRCT confirmed by histopathologic analysis. Among the 7 patients, 5 patients had undergone CT scanning, 2 of which were also examined with FDG-PET/CT imaging, and 2 had undergone MRI. Unenhanced and contrast-enhanced examinations were performed in all patients, and 2 patients had also undergone dynamic CT contrast-enhanced examinations. Image characteristics, such as shape, size, number, edge, attenuation, and intensity of each lesion before and after contrast enhancement were analyzed and compared with the pathomorphology of the tumors. Results: Multiple large masses in the abdominopelvis were detected in 6 cases, and a large mass in the pelvis was detected in 1 case. Six cases showed largest mass in pelvis, and 1 case in mesentery. None of the masses had a definite organ origin. CT showed soft tissue masses with patchy foci of hypodense areas. MR T1-weighted images revealed lesions with mild hypointense areas and patchy hypointense areas in 2 cases and lesions with patchy hyperintense areas in 1 case. T2-weighted images showed lesions with mixed isointense and hyperintense areas in 1 case and lesions with mixed hypointense, isointense, and hyperintense areas in another. Contrast-enhanced CT and T1-weighted images showed mildly heterogeneous enhancement of the lesions. Other associated findings included peritoneal seeding (n = 3), peritoneal effusions (n = 3), hepatic metastasis (n = 2), bone metastasis (n = 1), and mesenteric and retroperitoneal lymphadenopathy (n = 4). FDG-PET/CT showed multiple nodular foci of increased metabolic activity in the abdominopelvic masses, in the hepatic and

TU-G-207-01: CT Imaging Using Energy-Sensitive Photon-Counting Detectors

International Nuclear Information System (INIS)

Taguchi, K.

2015-01-01

Last few years has witnessed the development of novel of X-ray imaging modalities, such as spectral CT, phase contrast CT, and X-ray acoustic/fluorescence/luminescence imaging. This symposium will present the recent advances of these emerging X-ray imaging modalities and update the attendees with knowledge in various related topics, including X-ray photon-counting detectors, X-ray physics underlying the emerging applications beyond the traditional X-ray imaging, image reconstruction for the novel modalities, characterization and evaluation of the systems, and their practical implications. In addition, the concept and practical aspects of X-ray activatable targeted nanoparticles for molecular X-ray imaging will be discussed in the context of X-ray fluorescence and luminescence CT. Learning Objectives: Present background knowledge of various emerging X-ray imaging techniques, such as spectral CT, phase contrast CT and X-ray fluorescence/luminescence CT. Discuss the practical need, technical aspects and current status of the emerging X-ray imaging modalities. Describe utility and future impact of the new generation of X-ray imaging applications

Clinical Utility of SPECT/CT Imaging Post-Radioiodine Therapy: Does It Enhance Patient Management in Thyroid Cancer?

Science.gov (United States)

Hassan, Fahim U; Mohan, Hosahalli K

2015-12-01

The aim of this study was to evaluate post-therapy iodine-131 single-photon emission computed tomography/computed tomography ((131)I-SPECT/CT) imaging in comparison to conventional planar (131)I whole-body imaging, and to assess its clinical impact on the management of patients. We retrospectively reviewed planar (131)I whole-body and (131)I-SPECT/CT imaging findings in 67 patients who underwent (131)I therapy for thyroid cancer. Two nuclear medicine physicians reviewed the scans independently. The foci of increased tracer uptake were identified in the neck, thorax and elsewhere. Within the neck, the foci of (131)I-increased uptake were graded qualitatively as probable or definite uptake in thyroid remnants and probable or definite uptake in the lymph nodes. Serum thyroglobulin level, histopathology and other imaging findings served as the reference standard. Of the 67 patients, 57 (85%) had radioiodine avid disease and 10 (15%) demonstrated non-radioiodine avid disease. Overall, post-therapy (131)I-SPECT/CT downstaged lymph node staging in 10 patients and upstaged it in 4 patients. This translated into a change of management for 9/57 (16%) patients with radioiodine avid disease. A change of management was observed in 5/10 patients with non-radioiodine avid disease confirmed in the post-(131)I-SPECT/CT study. Additionally, clinically significant findings such as incidental lung cancer, symptomatic pleural effusion and consolidation were also diagnosed in both groups of patients. In patients with thyroid cancer, (131)I-SPECT/CT is a valuable addition to standard post-therapy planar imaging. SPECT/CT also improved diagnostic confidence and provided crucial clinical information leading to change of management for a significant number of these patients.

The generation of calandria tube (CT) inner diameter profiles from fuel channel (FC) inspection data

Energy Technology Data Exchange (ETDEWEB)

Sedran, P.J., E-mail: paul.sedran@amec.com [AMEC NSS, Toronto, ON (Canada); Rankin, B., E-mail: brankin@nbpower.com [NB Power, Fredericton, NB (Canada); Lemire, C., E-mail: Lemire.Christian@hydro.qc.ca [Hydro-Quebec, Montreal, QC (Canada)

2015-07-01

Studies of CT deformation at spacer locations, key to the development of FC deformation modelling, have been limited by the availability of gauging measurements from removed CTs. In [1], it was proposed that CT dimensional profiles could be generated using FC inspection data. Since then, the concept was investigated further by assessing: (1) the normalisation of gap measurements to the diameter of the spacer coil, (2) the validity of gap measurements from inspections of Point Lepreau and Gentilly-2, and the CT dimensional profiles generated from the inspection data.It was concluded, from the work presented in this paper, that the CT-PT gap data and the CT dimensional profiles generated using the data from the two subject inspections are reasonable. (author)

Comparison of five segmentation tools for 18F-fluoro-deoxy-glucose-positron emission tomography-based target volume definition in head and neck cancer.

Science.gov (United States)

Schinagl, Dominic A X; Vogel, Wouter V; Hoffmann, Aswin L; van Dalen, Jorn A; Oyen, Wim J; Kaanders, Johannes H A M

2007-11-15

Target-volume delineation for radiation treatment to the head and neck area traditionally is based on physical examination, computed tomography (CT), and magnetic resonance imaging. Additional molecular imaging with (18)F-fluoro-deoxy-glucose (FDG)-positron emission tomography (PET) may improve definition of the gross tumor volume (GTV). In this study, five methods for tumor delineation on FDG-PET are compared with CT-based delineation. Seventy-eight patients with Stages II-IV squamous cell carcinoma of the head and neck area underwent coregistered CT and FDG-PET. The primary tumor was delineated on CT, and five PET-based GTVs were obtained: visual interpretation, applying an isocontour of a standardized uptake value of 2.5, using a fixed threshold of 40% and 50% of the maximum signal intensity, and applying an adaptive threshold based on the signal-to-background ratio. Absolute GTV volumes were compared, and overlap analyses were performed. The GTV method of applying an isocontour of a standardized uptake value of 2.5 failed to provide successful delineation in 45% of cases. For the other PET delineation methods, volume and shape of the GTV were influenced heavily by the choice of segmentation tool. On average, all threshold-based PET-GTVs were smaller than on CT. Nevertheless, PET frequently detected significant tumor extension outside the GTV delineated on CT (15-34% of PET volume). The choice of segmentation tool for target-volume definition of head and neck cancer based on FDG-PET images is not trivial because it influences both volume and shape of the resulting GTV. With adequate delineation, PET may add significantly to CT- and physical examination-based GTV definition.

Comparison of Five Segmentation Tools for 18F-Fluoro-Deoxy-Glucose-Positron Emission Tomography-Based Target Volume Definition in Head and Neck Cancer

International Nuclear Information System (INIS)

Schinagl, Dominic A.X.; Vogel, Wouter V.; Hoffmann, Aswin L.; Dalen, Jorn A. van; Oyen, Wim J.; Kaanders, Johannes H.A.M.

2007-01-01

Purpose: Target-volume delineation for radiation treatment to the head and neck area traditionally is based on physical examination, computed tomography (CT), and magnetic resonance imaging. Additional molecular imaging with 18 F-fluoro-deoxy-glucose (FDG)-positron emission tomography (PET) may improve definition of the gross tumor volume (GTV). In this study, five methods for tumor delineation on FDG-PET are compared with CT-based delineation. Methods and Materials: Seventy-eight patients with Stages II-IV squamous cell carcinoma of the head and neck area underwent coregistered CT and FDG-PET. The primary tumor was delineated on CT, and five PET-based GTVs were obtained: visual interpretation, applying an isocontour of a standardized uptake value of 2.5, using a fixed threshold of 40% and 50% of the maximum signal intensity, and applying an adaptive threshold based on the signal-to-background ratio. Absolute GTV volumes were compared, and overlap analyses were performed. Results: The GTV method of applying an isocontour of a standardized uptake value of 2.5 failed to provide successful delineation in 45% of cases. For the other PET delineation methods, volume and shape of the GTV were influenced heavily by the choice of segmentation tool. On average, all threshold-based PET-GTVs were smaller than on CT. Nevertheless, PET frequently detected significant tumor extension outside the GTV delineated on CT (15-34% of PET volume). Conclusions: The choice of segmentation tool for target-volume definition of head and neck cancer based on FDG-PET images is not trivial because it influences both volume and shape of the resulting GTV. With adequate delineation, PET may add significantly to CT- and physical examination-based GTV definition