Metadata for scientific publications contain various explicit and implicit spatio-temporal references. Data on conference locations as well as author and editor affiliations – both changing over time ...– enable insights into the geographic distribution of scientific fields and particular specializations. At the same time, these byproducts of scientific bibliographies offer a great opportunity to integrate data across different bibliographies to get a more complete picture of a domain. In this paper, we demonstrate how the Linked Data paradigm can assist in enriching and integrating such collections. Starting from the bibliographies of the GIScience, COSIT, ACM GIS, and AGILE conference series, we show how to convert the data to Linked Data and integrate the previously separate datasets. We focus on the spatio-temporal aspects and discuss how they help in matching and disambiguating entities such as authors or universities. We introduce a novel user interface to explore the integrated dataset, demonstrating the potential of Linked Data for innovative applications using spatio-temporal information, and discuss how more complex queries can be addressed. While we focus on bibliographies, the presented work is part of the broader vision of a Linked Science infrastructure for e-Science.
The application service provider (ASP) model is not novel, but widely used in several non-health care-related business areas. In this article, ASP is described as a potential solution for long-term ...and back-up archiving of the picture archiving and communication system (PACS) of the Hospital District of Helsinki and Uusimaa (HUS). HUSpacs is a regional PACS for 21 HUS hospitals serving altogether 1.4 million citizens. The ultimate goal of this study was to define the specifications for the ASP archiving service and to compare different commercial options for archiving solutions (costs derived by unofficial requests for proposal): in-house PACS components, the regional ASP concept and the hospital-based ASP concept. In conclusion, the large scale of the HUS installation enables a cost-effective regional ASP archiving, resulting in a four to five times more economical solution than hospital-based ASP.
Radiation synovectomy is an effective technique for the treatment of chronic synovitis in patients with rheumatoid arthritis (RA), and is an alternative for surgical synovectomy. Holmium ferric ...hydroxide macroaggregates (166Ho-FHMA) is suitable for radiation synovectomy, especially because it emits high-energy beta particles and a smaller proportion of low-energy photons that are suitable for gamma-camera imaging.
The aim of this study was to develop a method to fuse 166Ho-FHMA single photon emission computed tomography (SPECT) and magnetic resonance (MRI) images, to show the distribution of 166Ho-FHMA inside the joint with images that localize synovitis.
The knees of 6 patients with RA were treated with 166Ho-FHMA. (99m)Tc-human immunoglobulin ((99m)Tc-HIG) SPECT images and MRI images were taken before 166Ho-FHMA injections. 166Ho-FHMA SPECT images were taken 4, 28, and 40 hours after injections. SPECT and MRI images were merged using a specific image fusion method, called mutual information algorithm, to study associations between anatomical and metabolic information from these images.
Fusion of SPECT and MRI images indicated that intensity of radioactivity was associated with the amount of synovitis. Activity distribution of 166Ho-FHMA could be registered using anatometabolic images.
A new method to fuse the distribution of radiation in the synovectomy of the knee was developed using SPECT/MRI image registration. Image registration of SPECT and MRI can be used to determine the activity distribution of radioisotopes in relation to synovitis.
Ambiguity and plausibility Ali, Ahmed Loai; Schmid, Falko; Al-Salman, Rami ...
Proceedings of the 22nd ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems,
11/2014
Conference Proceeding
With the ubiquity of technology and tools, current Volunteered Geographic Information (VGI) projects allow the public to contribute, maintain, and use geo-spatial data. One of the most prominent and ...successful VGI project is OpenStreetMap (OSM), where more than one million volunteers collected and contributed data that is obtainable for everybody. However, this kind of contribution mechanism is usually associated with data quality issues, e.g., geographic entities such as gardens or parks can be assigned with inappropriate classification by volunteers. Based on the observation that geographic features usually inherit certain properties and characteristics, we propose a novel classification-based approach allowing the identification of entities with inappropriate classification. We use the rich data set of OSM to analyze the properties of geographic entities with respect to their implicit characteristics in order to develop classifiers based on them. Our developed classifiers show high detection accuracies. However, due to the absence of proper training data we additionally performed a user study to verify our findings by means of intra-user-agreement. The results of our study support the detections of our classifiers and show that our classification-based approaches can be a valuable tool for managing and improving VGI data.
Content annotations in semantic cultural heritage portals commonly make spatiotemporal references to historical regions and places using names whose meanings are different in different times. For ...example, historical administrational regions such as countries, municipalities, and cities have been renamed, merged together, split into parts, and annexed or moved to and from other regions. Even if the names of the regions remain the same (e.g., “Germany”), the underlying regions and their relationships to other regions may change (e.g., the regional borders of “Germany” at different times). As a result, representing and finding the right ontological meanings for historical geographical names on the semantic web creates severe problems both when annotating contents and during information retrieval. This paper presents a model for representing the meaning of changing geospatial resources. Our aim is to enable precise annotation with temporal geospatial resources and to enable semantic search and browsing using related names from other historical time periods. A simple model and metadata schema is presented for representing and maintaining geospatial changes from which an explicit time series of temporal part-of ontologies can be created automatically. The model has been applied successfully to represent the complete change history of municipalities in Finland during 1865–2007. The resulting ontology time series is used in the semantic cultural heritage portal CultureSampo to support faceted semantic search of contents and to visualize historical regions on overlaying maps originating from different historical eras.
Nonuniform attenuation correction in brain SPECT can be done routinely by means of additional gamma transmission CT (TCT) measurements, using different commercially available line-source isotopes, ...201Tl, 153Gd, and 99mTc are among the most commonly used isotopes, depending on practical and cost-effectiveness issues. We have measured additional radiation burden from static uncollimated brain SPECT transmission sources for these isotopes. The influence of the transmission isotope on brain quantification was also measured and compared with uniform attenuation correction for phantom and human data. Full iterative transmission and emission reconstruction were compared with filtered backprojection techniques. Rod sources with 201Tl, 153Gd, and 99mTc were used on a triple-head gamma camera. Dosimetry was performed using LiF TLD-100 pellets and an anthropomorphic RANDO phantom. Effective dose equivalents were calculated on the basis of measured and extrapolated absorbed doses. For brain activity measurements, a Hoffman phantom was used. Images were corrected for scatter (triple-energy window) and were reconstructed by Chang attenuation correction and filtered backprojection as well as full iterative reconstruction (ordered-subsets expectation maximization OSEM). To study the effect of inhomogeneous bone attenuation, realistic measurements were performed on 10 young, healthy volunteers with 153Gd TCT. After stereotactic image realignment, a volume-of-interest analysis normalized to total counts was performed. Brain SPECT-TCT using 201Tl, 153Gd, and 99mTc produced total effective dose-rate equivalents of 50.3 +/- 11.2, 32.0 +/- 2.7, and 71.1 +/- 7.1 microSv/GBq x h, respectively, representing dose equivalents of 18.6, 11.9, and 26.3 microSv for a typical 20-min brain SPECT scan at maximal used source strength. Standardized quantification resulted in insignificant differences between the isotopes and methods (Chang versus OSEM) used for nonuniform correction. Iterative reconstruction enhanced image contrast and provided more accurate gray-to-white matter ratios. Between nonuniform and uniform attenuation with an optimized attenuation coefficient, slight central discrepancies were found for volunteer studies. Significantly lower intersubject variation was found for nonuniform corrected values in infratentorial and posterior brain regions. Brain transmission scanning using 201Tl, 153Gd, or 99mTc results in limited effective radiation dose equivalents compared with the typical radiation burden. Relative brain perfusion quantification is not significantly different for the various nonuniform TCT isotopes. Iterative reconstruction improves gray-to-white contrasts but has no significant influence on brain perfusion semiquantification. Nonuniform attenuation correction decreases intersubject variability in the posterior brain regions that were compared, which may lead to improved sensitivity toward clinical applications.
Filtered back-projection (FBP) is generally used as the reconstruction method for single-photon emission tomography although it produces noisy images with apparent streak artefacts. It is possible to ...improve the image quality by using an algorithm with iterative correction steps. The iterative reconstruction technique also has an additional benefit in that computation of attenuation correction can be included in the process. A commonly used iterative method, maximum-likelihood expectation maximisation (ML-EM), can be accelerated using ordered subsets (OS-EM). We have applied to the OS-EM algorithm a Bayesian one-step late correction method utilising median root prior (MRP). Methodological comparison was performed by means of measurements obtained with a brain perfusion phantom and using patient data. The aim of this work was to quantitate the accuracy of iterative reconstruction with scatter and non-uniform attenuation corrections and post-filtering in SPET brain perfusion imaging. SPET imaging was performed using a triple-head gamma camera with fan-beam collimators. Transmission and emission scans were acquired simultaneously. The brain phantom used was a high-resolution three-dimensional anthropomorphic JB003 phantom. Patient studies were performed in ten chronic pain syndrome patients. The images were reconstructed using conventional FBP and iterative OS-EM and MRP techniques including scatter and nonuniform attenuation corrections. Iterative reconstructions were individually post-filtered. The quantitative results obtained with the brain perfusion phantom were compared with the known actual contrast ratios. The calculated difference from the true values was largest with the FBP method; iteratively reconstructed images proved closer to the reality. Similar findings were obtained in the patient studies. The plain OS-EM method improved the contrast whereas in the case of the MRP technique the improvement in contrast was not so evident with post-filtering.
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