| 1. |
- Andersson, Jonny K, 1972, et al.
(författare)
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Cost description of clinical examination and MRI in wrist ligament injuries
- 2018
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Ingår i: Journal of Plastic Surgery and Hand Surgery. - : Medical Journals Sweden AB. - 2000-656X .- 2000-6764. ; 52:1, s. 30-36
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The total number and cost of wrist MRIs in the catchment area of the Vastra Gotaland Region in Sweden (population 1 723 000) during 1 year was analysed, together with the number and content of referrals. Methods: Six radiology departments reported the numbers and rate of all MRI investigations intended to diagnose wrist ligament injuries (n=411) and other injuries to the wrist. Results: The additional cost of the difference between MRIs and a clinical examination by a hand surgeon, plus indirect costs for patients with suspected wrist ligament injuries, was calculated as 957 000 euros. Conclusions: It is recommended that MRI should only be used in patients in whom there are clinical difficulties in terms of diagnosing wrist ligament injuries. It is suggested that patients with suspected wrist ligament injuries should be referred directly to an experienced hand surgeon, capable of performing a standardised wrist examination and, when needed, diagnostic arthroscopy and final treatment. The proposed algorithm for the diagnosis and treatment of suspected wrist ligament injuries presented in the present study could save time for the patient and for the radiology departments, as well as reducing costs. The ability to implement the early and appropriate treatment of acute ligament injuries could be improved at the same time.
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| 2. |
- Andersson, Ronnie, 1975, et al.
(författare)
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Druckbehälter
- 2018
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Patent (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Balk, Lennart, et al.
(författare)
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Biomarkers in Natural Fish Populations Indicate Adverse Biological Effects of Offshore Oil Production
- 2011
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:5, s. e19735-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Despite the growing awareness of the necessity of a sustainable development, the global economy continues to depend largely on the consumption of non-renewable energy resources. One such energy resource is fossil oil extracted from the seabed at offshore oil platforms. This type of oil production causes continuous environmental pollution from drilling waste, discharge of large amounts of produced water, and accidental spills. Methods and principal findings: Samples from natural populations of haddock (Melanogrammus aeglefinus) and Atlantic cod (Gadus morhua) in two North Sea areas with extensive oil production were investigated. Exposure to and uptake of polycyclic aromatic hydrocarbons (PAHs) were demonstrated, and biomarker analyses revealed adverse biological effects, including induction of biotransformation enzymes, oxidative stress, altered fatty acid composition, and genotoxicity. Genotoxicity was reflected by a hepatic DNA adduct pattern typical for exposure to a mixture of PAHs. Control material was collected from a North Sea area without oil production and from remote Icelandic waters. The difference between the two control areas indicates significant background pollution in the North Sea. Conclusion: It is most remarkable to obtain biomarker responses in natural fish populations in the open sea that are similar to the biomarker responses in fish from highly polluted areas close to a point source. Risk assessment of various threats to the marine fish populations in the North Sea, such as overfishing, global warming, and eutrophication, should also take into account the ecologically relevant impact of offshore oil production.
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| 4. |
- Brandberg, Y, et al.
(författare)
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Health-related quality of life in patients with high-risk melanoma randomised in the Nordic phase 3 trial with adjuvant intermediate-dose interferon alfa-2b.
- 2012
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Ingår i: European journal of cancer. - : Elsevier BV. - 1879-0852 .- 0959-8049. ; 48:13, s. 2012-2019
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To compare health-related quality of life (HRQoL) and side-effects in patients with high-risk melanoma participating in a randomised phase III trial of adjuvant interferon alfa-2b (IFN). PATIENTS AND METHODS: A total of 855 patients with histologically verified resected cutaneous melanoma in AJCC stage IIb (T4 N0 M0) or stage III (Tx N1-3 M0) were randomised to: Arm A: observation only (n=284); Arm B: 1-year treatment: induction: IFN alfa-2b, 10 MU (flat dose), SC, 5days/week, 4weeks, maintenance: IFN alfa-2b, 10 MU (flat dose), SC, 3days/week for 12months (n=285); or Arm C: 2years of same treatment as Arm B. HRQoL was assessed using The European Organisation for Research and Treatment of Cancer Core Questionnaire (EORTC QLQ-C30) before randomisation and at 8 pre-defined time-points during 2years. IFN-related side-effects were assessed by a study-specific questionnaire. RESULTS: >80% of eligible patients returned questionnaires at the different assessment points. Statistically significant interactions between randomisation arm and time after randomisation were found for almost all EORTC QLQ-30 variables. While patients in Arm A improved or remained at baseline levels; patients in Arms B and C reported decreased functioning and quality of life, and an increase in side-effects during their treatment. Patients in Arm B improved after the 12th month assessment, when IFN treatment was scheduled to end, to the 16th month assessment (p<0.001). The same pattern of improvement was found for 5 of 7 interferon-related side-effects. CONCLUSION: A significant negative impact on HRQoL of IFN treatment was demonstrated, however the impact were reversible when treatment was stopped.
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| 5. |
- Båth, Magnus, 1974, et al.
(författare)
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A conceptual optimisation strategy for radiography in a digital environment.
- 2005
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 114:1-3, s. 230-5
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Tidskriftsartikel (refereegranskat)abstract
- Using a completely digital environment for the entire imaging process leads to new possibilities for optimisation of radiography since many restrictions of screen/film systems, such as the small dynamic range and the lack of possibilities for image processing, do not apply any longer. However, at the same time these new possibilities lead to a more complicated optimisation process, since more freedom is given to alter parameters. This paper focuses on describing an optimisation strategy that concentrates on taking advantage of the conceptual differences between digital systems and screen/film systems. The strategy can be summarised as: (a) always include the anatomical background during the optimisation, (b) perform all comparisons at a constant effective dose and (c) separate the image display stage from the image collection stage. A three-step process is proposed where the optimal setting of the technique parameters is determined at first, followed by an optimisation of the image processing. In the final step the optimal dose level-given the optimal settings of the image collection and image display stages-is determined.
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| 6. |
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| 7. |
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| 8. |
- Båth, Magnus, 1974, et al.
(författare)
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VGC ANALYZER: A SOFTWARE FOR STATISTICAL ANALYSIS OF FULLY CROSSED MULTIPLE-READER MULTIPLE-CASE VISUAL GRADING CHARACTERISTICS STUDIES
- 2016
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1-4, s. 46-53
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Tidskriftsartikel (refereegranskat)abstract
- Visual grading characteristics (VGC) analysis is a non-parametric rank-invariant method for analysis of visual grading data. In VGC analysis, image quality ratings for two different conditions are compared by producing a VGC curve, similar to how the ratings for normal and abnormal cases in receiver operating characteristic (ROC) analysis are used to create an ROC curve. The use of established ROC software for the analysis of VGC data has therefore previously been proposed. However, the ROC analysis is based on the assumption of independence between normal and abnormal cases. In VGC analysis, this independence cannot always be assumed, e.g. if the ratings are based on the same patients imaged under both conditions. A dedicated software intended for analysis of VGC studies, which takes possible dependencies between ratings into account in the statistical analysis of a VGC study, has therefore been developed. The software-VGC Analyzer-determines the area under the VGC curve and its uncertainty using non-parametric resampling techniques. This article gives an introduction to VGC Analyzer, describes the types of analyses that can be performed and instructs the user about the input and output data.
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| 9. |
- Båth, Magnus, 1974, et al.
(författare)
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VGC Analyzer – a software for statistical analysis of multiple-reader multiple-case visual grading characteristics (VGC) studies
- 2015
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Ingår i: Optimisation in X-ray and Molecular Imaging 2015 - the Fourth Malmö Conference on Medical Imaging, Gothenburg, Sweden, 28-30 May 2015.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Visual grading characteristics (VGC) analysis is a non-parametric rank-invariant method for analysis of visual grading data. In VGC analysis, image quality ratings for two different systems are compared by producing a VGC curve, similar to how the ratings for normal and abnormal cases in receiver operating characteristic (ROC) analysis are used to create an ROC curve. The use of established ROC software for the analysis of VGC data has therefore previously been proposed. However, ROC analysis is based on the assumption of independence between normal and abnormal cases. In VGC analysis this independence cannot always be assumed, e.g. if the ratings are based on the same patients imaged with both systems. The purpose of the present work was therefore to develop a software that takes possible dependencies between ratings into account in the statistical analysis of a VGC study. A computer program that performs a statistical analysis of rating data from a fully-crossed multiple-reader multiple-case VGC study was written in IDL (Research Systems, Inc., Boulder, CO). The software – VGC Analyzer – determines the area under the VGC curve (AUCVGC) averaged over the readers and applies non-parametric methods for the statistical tests: a bootstrapping resampling technique to determine the confidence interval of the AUCVGC and a permutation resampling technique to determine the p-value for testing the null hypothesis that the two compared systems are equal (AUCVGC=0.5). A paired resampling is used if there is a dependency between the ratings for the two modalities. Analyses are performed both based on the trapezoidal and the binormal VGC curves and results are given both for the fixed-reader and the random-reader situations. VGC Analyzer can be obtained freely from the authors, and can hopefully simplify the use of VGC analysis in evaluations of image quality.
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| 10. |
- Carlander, Anna, et al.
(författare)
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The effect of radiation dose reduction on clinical image quality in chest radiography of premature neonates using a dual-side readout technique computed radiography system
- 2010
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 139:1-3, s. 275-280
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present study was to investigate if the exposure could be reduced from the clinical setting (resulting in an effective dose of 8 microSv for a neonate of weight 0.7 kg and height 25 cm at a tube voltage of 90 kV) without negatively influencing the image quality for a dual-side readout technique computed radiography (CR) system in chest radiography of premature neonates. Chest radiographs of premature neonates were acquired with the double-side readout technique CR system. The images underwent simulated dose reduction in steps of 20 % to represent five different radiation dose levels. Four image quality criteria, related to the visibility of important anatomical structures, were used in a visual grading study where five experienced radiologists rated how well the criteria were fulfilled for all images. When reducing the radiation dose, a decrease in image quality could be observed already at the 80 % dose level for all the structures. The results indicate that a decrease in exposure from the clinically used setting affects the image quality negatively for the CR system.
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| 11. |
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| 12. |
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| 13. |
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| 14. |
- Daborg, Jonny, et al.
(författare)
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Cerebrospinal fluid levels of complement proteins C3, C4 and CR1 in Alzheimer's disease.
- 2012
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Ingår i: Journal of neural transmission (Vienna, Austria : 1996). - : Springer Science and Business Media LLC. - 1435-1463 .- 0300-9564. ; 119:7, s. 789-97
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is strongly associated with loss of synapses. The complement system has been shown to be involved in synaptic elimination. Several studies point to an association between AD and the complement system. The purpose of this study was to examine the association of cerebrospinal fluid (CSF) levels of complement components 3 and 4 (C3 and C4, respectively), and complement receptor 1 (CR1) with AD in 43 patients with AD plus dementia, 42 patients with mild cognitive impairment (MCI) who progressed to AD during follow-up (MCI-AD), 42 patients with stable MCI and 44 controls. Complement levels were also applied in a multivariate model to determine if they provided any added value to the core AD biomarkers Aβ42, T-tau and P-tau. We found elevated CSF levels of C3 and C4 in AD compared with MCI without progression to AD, and elevated CSF levels of CR1 in MCI-AD and AD when these groups were merged. These results provide support for aberrant complement regulation as a part in the AD process, but the changes are not diagnostically useful.
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| 15. |
- Hansson, Jonny, et al.
(författare)
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A practical approach to prioritise among optimisation tasks in X-ray imaging: introducing the 4-bit concept
- 2010
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 139:1-3, s. 393-399
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Tidskriftsartikel (refereegranskat)abstract
- According to European and national legislation, as well as international recommendations, X-ray examinations shall be optimised. However, with limited resources and hundreds of different types of X-ray examinations, it may be difficult to prioritise among the optimisation tasks at a radiology department. This work is focused on describing a method that can be used to determine the order of which the examinations should be optimised. In the Medical Exposure Directive from 1997, the European Commission prescribes the content of an optimisation process in relation to medical exposure. A reasonable interpretation of the directive is that the assurance of medical purpose for a justified examination is superior to the need of decreased radiation dose. This was used as a basis for developing a method for prioritisation among optimisation tasks. For each examination type, the following four yes/no questions are raised: (i) Is the present image quality unacceptable? (ii) Is the examination of particular importance? (iii) Is the radiation dose suspiciously high? (iv) Are there special dose level concerns, e.g. diagnostic reference levels? Arguing that a positive response to any of the four questions results in the examination being higher prioritised than otherwise and that the questions are labelled in order of decreasing relevance, it can be shown that the resulting flow chart, determining the order of which the examinations should be optimised, can be described by a 4-bit binary scale. In this way, each examination type is given a number from 0 to 15, a higher number corresponding to the examination being prioritised higher in the optimisation work. The method was applied to a general radiology department and resulted in a well-discriminated distribution of examinations prioritised for optimisation tasks. In conclusion, taking into account both medical outcome and potential risk, the proposed method can be used to determine the order in which examinations at a radiology department should be optimised.
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| 16. |
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| 17. |
- Hansson, Jonny, et al.
(författare)
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An optimisation strategy in a digital environment applied to neonatal chest imaging.
- 2005
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 114:1-3, s. 278-85
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to find the optimum tube voltage for neonatal chest imaging in computed radiography. The study was designed to take full advantage of the benefits of digital imaging, for example, by comparing the tube voltages at constant effective dose. A phantom study using a living rabbit was first conducted. Images were collected at tube voltages ranging from 40 to 90 kV(p). The reproduction of four structures (central vessels, peripheral vessels, carina and thoracic vertebrae) was rated by 10 radiologists. The reproduction of both central and peripheral vessels was relatively independent of tube voltage. The carina was better reproduced at higher tube voltages whereas the opposite was true for the thoracic vertebrae. Based on the higher importance of the reproduction of the carina it was decided that 90 kV(p) was the optimal tube voltage. To validate the result from the phantom study, a follow-up study was conducted in which images of neonates collected at the tube voltage regularly used at Sahlgrenska University Hospital (70 kV(p)) were compared with images collected at the tube voltage proposed by the phantom study. The follow-up study confirmed the results from the phantom study that the reproduction of the carina was better at 90 than at 70 kV(p). In conclusion, for neonatal chest imaging-given the same effective dose-90 kVp gives better reproduction of important structures than the regularly used 70 kV(p).
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| 18. |
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| 19. |
- Hansson, Jonny, et al.
(författare)
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Comparison of three methods for determining CT dose profile: presenting the tritium method
- 2010
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 139:1-3, s. 434-438
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present work was to describe a method of using an imaging plate from a computed radiography system to determine the computed tomography (CT) dose profile (the tritium method) and to compare this method with point-dose measurements using a solid-state detector (CT Dose Profiler; RTI Electronics, Mölndal, Sweden) and the indirect method of comparing the air kerma-length product (P(KL)) at different beam collimations. The three methods were used to determine the full width at half maximum (FWHM) of the dose profile of a multi-slice CT at different nominal beam collimations. For all beam collimations, the obtained deviation between the tritium method and the CT Dose Profiler was smaller than 0.1 mm. The maximum relative error was 2 %. For the P(KL) method, the deviation from the CT Dose Profiler was between 0.2 and 0.4 mm, resulting in a relative error larger than 10 % for the smallest beam collimation even after normalisation to a known FWHM. In conclusion, the proposed method of using an imaging plate to determine the FWHM of the CT dose profile has a high accuracy and shows good agreement with the more advanced method of point-dose measurements using a solid-state detector.
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| 20. |
- Hansson, Jonny
(författare)
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Development of methods and strategies for optimisation of x-ray examinations
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The overall aim of the work presented in this thesis was to develop methods and strategies for the optimisation process prescribed by legal authorities for medical X-ray imaging. This overall aim was divided into four detailed aims: 1) to analyse and describe the conditions for the optimisation of a given projectional X-ray examination in a digital environment, 2) to develop an overall strategy for the optimisation work in a radiology department, 3) to develop and implement a suitable method for statistical analysis of visual grading characteristics (VGC) data, and, 4) to evaluate the characteristics of the new statistical method by comparison with receiver operating characteristics (ROC) statistical methodology and by simulations. The four aims are coupled to the five papers presented in this thesis. In Paper I, the conditions for the optimisation of a given projectional X-ray examination in a digital environment are analysed and a proposed optimisation strategy, based on the analysis, is described. In Paper II an overall strategy for the prioritisation of the optimisation work in a radiology department is presented. Paper III describes the development of a suitable method for statistical analysis of VGC data, which is implemented in the software VGC Analyzer. In Papers IV and V, the characteristics of the new statistical method are thoroughly evaluated by comparison with ROC statistical methodology and by simulations. The strategies developed helped clarify the prerequisites in the process of optimising medical X-ray imaging and were shown to be useful in clinical applications. However, the objective of optimising the radiation protection in medical use of radiation is not fully clarified in legal requirements, and needs further discussion. The development of resampling methods for statistical analysis of VGC data, implemented in VGC Analyzer, provides a method that is easy to apply in clinical optimisation projects where visual grading is judged to be the appropriate evaluation method.
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| 21. |
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| 22. |
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| 23. |
- Hansson, Jonny, et al.
(författare)
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EVALUATION OF VGC ANALYZER BY COMPARISON WITH GOLD STANDARD ROC SOFTWARE AND ANALYSIS OF SIMULATED VISUAL GRADING DATA
- 2021
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 0144-8420 .- 1742-3406. ; 195:3-4, s. 378-390
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present work was to evaluate the use of resampling statistical methods for analysis of visual grading data-implemented in the software VGC Analyzer-by comparing the reanalyzed results from previously performed visual grading studies with the results calculated by gold standard receiver operating characteristic (ROC) methodology, Obuchowski-Rockette (OR)-Dorfman-Berbaum-Metz (DBM) multiple-readers and multiple-case (MRMC) and by analysis of simulated visual grading data where the true distribution was presumed to be known. The reanalysis was performed on two multiple-reader studies with non-paired data and paired data, respectively. The simulation study was performed by simulating a large number of visual grading characteristics (VGC) studies and by analyzing the statistical distribution of null hypothesis (H-0) rejection rate. The comparison with OR-DBM MRMC showed good agreement when analyzing non-paired data for both fixed-reader and random-reader settings for the calculated area under the curve values and the confidence intervals (CIs). For paired data analysis, VGC Analyzer showed significantly lower CIs compared with the ROC software. This effect was also illustrated by the simulation study, where the VGC Analyzer, in general, showed good accuracy for simulated studies with stable statistical basis. For simulated studies with unstable statistics, the accuracy in the H-0 rejection rate decreased. The present study has shown that resampling methodology can be used to accurately perform the statistical analysis of a VGC study, although the resampling technique used makes the method sensitive to small data sets.
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| 24. |
- Hansson, Jonny, et al.
(författare)
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Reanalysis of visual grading characteristics (VGC) data using VGC Analyzer
- 2015
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Ingår i: Optimisation in X-ray and Molecular Imaging 2015 - the Fourth Malmö Conference on Medical Imaging, Gothenburg, Sweden, 28-30 May 2015.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Purpose: Visual grading studies have a weak point in that the statistical evaluation of collected data is often performed in a questionable manner. The introduction of visual grading characteristics (VGC) analysis in 2007 aimed at an improvement by presenting a non-parametric rank-invariant method of comparing visual grading data from two modalities. The resulting figure-of-merit, the area under the VGC curve (AUCVGC), was initially proposed to be determined using standard software for receiver operating characteristics (ROC) analysis. However, due to different properties of ROC and VGC data, it can be assumed that the uncertainty of the AUCVGC is not determined correctly using ROC software. A novel developed software tool (VGC Analyzer) for statistical analysis of VGC data using non-parametric resampling methods has recently been verified on simulated data. The purpose of the present work was to reanalyse data from previously published VGC studies using VGC Analyzer in order to evaluate the validity of the reported results of the previous studies and to investigate the behaviour of VGC Analyzer on real data. Method: Visual grading data from previously performed studies on optimisation of x-ray examinations were reanalysed using VGC Analyzer. The outcome (the mean and 95% confidence interval (CI) of the AUCVGC and the p-value) was compared with previously reported data from the studies where single reader adapted ROC software had been used and rating data from multiple readers had been pooled. The studies included both paired and non-paired data and were analysed using both fixed readers and random readers. Major findings: The results showed good agreement between the AUCVGC determined with VGC Analyzer and the previously used methods. However, on non-paired data, narrower CIs were reported by previous studies compared to VGC Analyzer whereas in one study with paired data the reported CIs were similar or even broader using ROC software. Significance testing based on the CI and the p-value from VGC Analyzer in most cases gave the same result, but sometimes led to different results in statistically weak studies when the random reader approach was used. In these cases a p-value < 0.05 was obtained although the CI of the AUCVGC included 0.5. Conclusions: The results of the present work indicate that studies using single reader adapted ROC software for analysing VGC data may, especially in non-paired data studies, underestimate the uncertainty of the obtained AUCVGC, leading to an increased risk of Type I errors. On the other hand, incorrect use of ROC software for analysis of paired data may overestimate the uncertainty of the obtained AUCVGC, leading to increased risk of Type II errors.
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| 25. |
- Hansson, Jonny, et al.
(författare)
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THE VALIDITY OF USING ROC SOFTWARE FOR ANALYSING VISUAL GRADING CHARACTERISTICS DATA: AN INVESTIGATION BASED ON THE NOVEL SOFTWARE VGC ANALYZER
- 2016
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1-4, s. 54-59
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present work was to investigate the validity of using single-reader-adapted receiver operating characteristics (ROC) software for analysis of visual grading characteristics (VGC) data. VGC data from four published VGC studies on optimisation of X-ray examinations, previously analysed using ROCFIT, were reanalysed using a recently developed software dedicated to VGC analysis (VGC Analyzer), and the outcomes [the mean and 95 % confidence interval (CI) of the area under the VGC curve (AUCVGC) and the p-value] were compared. The studies included both paired and non-paired data and were reanalysed both for the fixed-reader and the random-reader situations. The results showed good agreement between the softwares for the mean AUCVGC. For non-paired data, wider CIs were obtained with VGC Analyzer than previously reported, whereas for paired data, the previously reported CIs were similar or even broader. Similar observations were made for the p-values. The results indicate that the use of single-reader-adapted ROC software such as ROCFIT for analysing non-paired VGC data may lead to an increased risk of committing Type I errors, especially in the random-reader situation. On the other hand, the use of ROC software for analysis of paired VGC data may lead to an increased risk of committing Type II errors, especially in the fixed-reader situation.
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| 26. |
- Häggström, Margaretha, 1962, et al.
(författare)
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Att undervisa i hållbar utveckling - Relationellt perspektiv
- 2022
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Hur kan lärare arbeta med hållbar utveckling i en tid då globala kriser och klimatförändringar väcker både rädsla och oro? Och hur kan elever samtidigt känna hopp inför sin framtid och sitt vuxna liv? Dessa frågor är utgångspunkt för det utvecklings- och forskningsprojekt som utgör basen i denna bok. Du får följa med i berättelser som lärare och elever skapat tillsammans för att utveckla kunskap om social, ekologisk och ekonomisk hållbarhet. Boken redogör för de pedagogiska utgångspunkterna, men ger också rikligt med praktiska exempel på metoder och former för undervisning i och genom demokratiska och relationella förhållningssätt. Du får konkreta tips på hur du kan integrera hållbar utveckling i undervisningen. Såväl kritiska aspekter som lärdomar och möjligheter lyfts fram. I centrum står eleven och läraren utifrån det relationspedagogiska perspektivet. Att undervisa i hållbar utveckling: Relationellt perspektiv vänder sig till lärarstudenter och verksamma lärare i årskurs F-6. Bokens syfte är att inspirera, stödja och utgöra diskussionsunderlag i skolans arbete med miljöperspektivet och hållbar utveckling.
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| 27. |
- Jonny, Ahs, et al.
(författare)
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DE 112009002424 T5
- 2012
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Patent (övrigt vetenskapligt/konstnärligt)
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| 28. |
- Portelius, Erik, 1977, et al.
(författare)
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Distinct cerebrospinal fluid amyloid beta peptide signatures in sporadic and PSEN1 A431E-associated familial Alzheimer's disease.
- 2010
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Ingår i: Molecular neurodegeneration. - : Springer Science and Business Media LLC. - 1750-1326. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Alzheimer's disease (AD) is associated with deposition of amyloid beta (Abeta) in the brain, which is reflected by low concentration of the Abeta1-42 peptide in the cerebrospinal fluid (CSF). There are at least 15 additional Abeta peptides in human CSF and their relative abundance pattern is thought to reflect the production and degradation of Abeta. Here, we test the hypothesis that AD is characterized by a specific CSF Abeta isoform pattern that is distinct when comparing sporadic AD (SAD) and familial AD (FAD) due to different mechanisms underlying brain amyloid pathology in the two disease groups. RESULTS: We measured Abeta isoform concentrations in CSF from 18 patients with SAD, 7 carriers of the FAD-associated presenilin 1 (PSEN1) A431E mutation, 17 healthy controls and 6 patients with depression using immunoprecipitation-mass spectrometry. Low CSF levels of Abeta1-42 and high levels of Abeta1-16 distinguished SAD patients and FAD mutation carriers from healthy controls and depressed patients. SAD and FAD were characterized by similar changes in Abeta1-42 and Abeta1-16, but FAD mutation carriers exhibited very low levels of Abeta1-37, Abeta1-38 and Abeta1-39. CONCLUSION: SAD patients and PSEN1 A431E mutation carriers are characterized by aberrant CSF Abeta isoform patterns that hold clinically relevant diagnostic information. PSEN1 A431E mutation carriers exhibit low levels of Abeta1-37, Abeta1-38 and Abeta1-39; fragments that are normally produced by gamma-secretase, suggesting that the PSEN1 A431E mutation modulates gamma-secretase cleavage site preference in a disease-promoting manner.
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| 29. |
- Precht, H., et al.
(författare)
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Radiographers' perspectives' on Visual Grading Analysis as a scientific method to evaluate image quality
- 2019
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Ingår i: Radiography. - : Elsevier BV. - 1078-8174. ; 25:Suppl. 1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Radiographers routinely undertake many initiatives to balance image quality with radiation dose (optimisation). For optimisation studies to be successful image quality needs to be carefully evaluated. Purpose was to 1) discuss the strengths and limitations of a Visual Grading Analysis (VGA) method for image quality evaluation and 2) to outline the method from a radiographer's perspective. Methods: A possible method for investigating and discussing the relationship between radiographic image quality parameters and the interpretation and perception of X-ray images is the VGA method. VGA has a number of advantages such as being low cost and a detailed image quality assessment, although it is limited to ensure the images convey the relevant clinical information and relate the task based radiography. Results: Comparing the experience of using VGA and Receiver Operating Characteristic (ROC) it is obviously that less papers are published on VGA (Pubmed n=1.384) compared to ROC (Pubmed n=122.686). Hereby the scientific experience of the VGA method is limited compared to the use of ROC. VGA is, however, a much newer method and it is slowly gaining more and more attention. Conclusion: The success of VGA requires a number of steps to be completed, such as defining the VGA criteria, choosing the VGA method (absolute or relative), including observers, finding the best image display platforms, training observers and selecting the best statistical method for the study purpose should be thoroughly considered. (C) 2019 Published by Elsevier Ltd on behalf of The College of Radiographers.
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| 30. |
- Svalkvist, Angelica, et al.
(författare)
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Comparison of different approaches of estimating effective dose from reported exposure data in 3D imaging with interventional fluoroscopy systems
- 2014
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Ingår i: SPIE Medical Imaging 2014, 15-20 February 2014, San Diego, California, USA. Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE. - 1605-7422. ; 9033
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Three-dimensional (3D) imaging with interventional fluoroscopy systems is today a common examination. The examination includes acquisition of two-dimensional projection images, used to reconstruct section images of the patient. The aim of the present study was to investigate the difference in resulting effective dose obtained using different levels of complexity in calculations of effective doses from these examinations. In the study the Siemens Artis Zeego interventional fluoroscopy system (Siemens Medical Solutions, Erlangen, Germany) was used. Images of anthropomorphic chest and pelvis phantoms were acquired. The exposure values obtained were used to calculate the resulting effective doses from the examinations, using the computer software PCXMC (STUK, Helsinki, Finland). The dose calculations were performed using three different methods: 1. using individual exposure values for each projection image, 2. using the mean tube voltage and the total DAP value, evenly distributed over the projection images, and 3. using the mean kV and the total DAP value, evenly distributed over smaller selection of projection images. The results revealed that the difference in resulting effective dose between the first two methods was smaller than 5%. When only a selection of projection images were used in the dose calculations the difference increased to over 10%. Given the uncertainties associated with the effective dose concept, the results indicate that dose calculations based on average exposure values distributed over a smaller selection of projection angles can provide reasonably accurate estimations of the radiation doses from 3D imaging using interventional fluoroscopy systems. © 2014 SPIE.
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| 31. |
- Svalkvist, Angelica, et al.
(författare)
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Comparison of different approaches of estimating the effective dose from CBCT examinations performed using interventional fluoroscopy systems
- 2013
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Ingår i: Nationellt möte om sjukhusfysik 2013, 13-14 november 2013, Varberg.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Three-dimensional (3D) imaging with interventional fluoroscopy systems is today a common examination. The examination includes the collection of a large number of twodimensional projection images of the patient. The projection images are then used to reconstruct CT like images of the patient. The technique is often referred to as cone-beam CT (CBCT). The resulting patient radiation doses from CBCT examinations have previously been reported to be comparable to the radiation doses from conventional CT examinations. However, determining the radiation doses from CBCT examinations is not a straight-forward task. Especially as detailed exposure parameters from the examinations are not provided by the system commercially available. Hence, variations in exposure parameters between the different projection images included in the examination can not always be accounted for. The aim of this study was therefore to evaluate the errors connected to using different methods for calculating the radiation doses from CBCT examinations performed using interventional fluoroscopy systems. In the study the Siemens Artis Zee interventional fluoroscopy system (Siemens Medical Solutions, Erlangen, Germany) was used. An eight-second DynaCT digital radiography protocol was used to collect images of the anthropomorphic pelvis phantom. The exposure values obtained from the examination was used to perform Monte Carlo based calculations of the effective doses resulting from the examination, using the computer software PCXMC (STUK, Helsinki, Finland). Both individual exposure values (kV and mAs) for each projection image included in the examination and constant mean values (kV/mAs and DAP) for all projections were used as input for the dose calculations. In addition, the effects of not including all the projection images in the dose calculations were investigated. Preliminary results show that the effective dose from a pelvis examination using this system is approximately 6 mSv. Only very small variations in resulting effective doses were found between the different methods used for dose calculations (variations smaller than 4%). The results thereby indicate that simplified dose calculations, e.g. using mean exposure values and/or not accounting for each projection image included in the examination, can be used to estimate the radiation doses from CBCT examinations performed using interventional fluoroscopy systems with reasonable accuracy
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| 32. |
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| 33. |
- Thilander-Klang, Anne, 1959, et al.
(författare)
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Evaluation of subjective assessment of the low-contrast visibility in constancy control of computed tomography
- 2010
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 139:1-3, s. 449-454
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the present work was to investigate the reliability of subjective assessments of the low-contrast visibility in constancy control of computed tomography (CT). Axial CT images of a low-contrast phantom were acquired on an 8-slice multi-detector CT scanner at nine tube current settings ranging from 75 to 440 mA. Five medical physicists assessed the visibility of the low-contrast details in two sessions. In the first session, containing 54 images, the visibility was rated on an absolute scale by determining the number of visible details in each contrast group in each image. In the second session, 180 image pairs were presented to the observers with the task of determining if the two images had been acquired under identical conditions or not. In the absolute session, both the intra- and inter-observer variabilities were high. In the relative session, the variability was smaller, but an exposure difference of 50 % was needed for all observers to correctly identify a change in all cases. In conclusion, the present study indicates that subjective assessments of the low-contrast visibility in constancy control of CT are not reliable.
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| 34. |
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| 35. |
- Thilander-Klang, Anne, 1959, et al.
(författare)
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Kontroll av moderna datortoramografer
- 2004
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Ingår i: Röntgenveckan 2004, Göteborg, 6-10 september 2004.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 36. |
- Zachrisson, Sara, et al.
(författare)
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Optimering av urografiundersökningar
- 2007
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Ingår i: Nationellt möte om Sjukhusfysik, 20-21 September 2007, Eskilstuna.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 37. |
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| 38. |
- Zachrisson, Sara, et al.
(författare)
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Optimisation of tube voltage for conventional urography using a Gd2O2S:Tb flat panel detector
- 2010
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Ingår i: Radiation protection dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 139:1-3, s. 86-91
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Tidskriftsartikel (refereegranskat)abstract
- With the increasing use of computed tomography (CT) for urography examinations, the indications for 'conventional' projection urography have changed and are more focused on high-contrast details. The purpose of the present study was to optimise the beam quality for urography examinations performed with a Gd(2)O(2)S:Tb flat-panel detector for the new conditions. Images of an anthropomorphic phantom were collected at different tube voltages with a CXDI-40G detector (Canon Inc., Tokyo, Japan). The images were analysed by radiologists and residents in a visual grading characteristics (VGCs) study. The tube voltage resulting in the best image quality was 55 kV, which therefore was selected for a clinical study. Images from 62 patients exposed with either 55 or 73 kV (original tube voltage) at constant effective doses were included. The 55-kV images underwent simulated dose reduction to represent images collected at 80, 64, 50, 40 and 32 % of the original dose level. All images were included in a VGC study where the observers rated the visibility of important anatomical landmarks. For images collected at 55 kV, an effective dose of approximately 85 % resulted in the same image quality as for images collected at 73 kV at 100 % dose. In conclusion, a low tube voltage should be used for conventional urography focused on high-contrast details. The study indicates that using a tube voltage of 55 kV instead of 73 kV for a Gd(2)O(2)S:Tb flat-panel detector, the effective dose can be reduced by approximately 10-20 % for normal-sized patients while maintaining image quality.
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