Introduction and aim: In SPECT imaging, the finite spatial resolution of the imaging system leads to a blurring of the reconstructed image. Consequently, counts originating from each point in the source distribution will be spread out over a volume in the reconstructed image, leading to spill-over of counts between different structures and distortion of the apparent activity concentration. This pr

Introduction: The purpose of this study was to develop a technique for automatic segmentation based on Fourier descriptors for separating smooth objects from the background in SPECT-images. The aim of the segmentation method was to be able to automatically outline kidneys in SPECT-images of patients undergoing radionuclide therapy with 177Lu-DOTATATE. The potential advantage of combining SPECT- an

Purpose: The main purposes of this study is to a) evaluate the suitability of a Varian aS1000 EPID as a safe quality assurance device for control of machine specific parameters, such as linac output, beam quality and beam symmetry, and b) to investigate the usefulness of the SPC concept for evaluation of the obtained data. Method and Materials: Measurements were performed using a Varian Clinac 23

Radiochromic film, polymer gel and radiochromic plastic are three different kinds of dosimeters developed for radiation therapy. Even though all three types of dosimeters are suitable for optical scanning, the proposed readout method is different for each detector system. In this study, the scanning properties of three optical CT scanners were investigated to determine if they could be developed i

Diffusion MRI is an imaging technique capable of inferring information about the tissue microstructure, based on magnetic resonance imaging (MRI). Diffusion MRI data can be analysed using tractography, a tool able to represent the structure of the white matter (WM) in the brain. Tractography is commonly used qualitatively, but in this report, an algorithm for quantitative tractography was develope

Diffusion tensor magnetic resonance imaging (DT-MRI or DTI) is an imaging technique that is sensitive to the diffusion movement of water contained in tissue. It is used to quantify parameters such as the diffusivity and its directionality. Because diffusion is intimately connected to the tissue microarchitecture DTI is one of the few techniques that can quantify tissue microstructure non-invasivel

Breast tomosynthesis (BT) is a new X-ray modality that reconstructs the breast volume in many slices instead of, as in mammography, showing a single 2D projection of the breast. The slice thickness is typically 1 mm for clinically used BT-units. In screening the review of breast images with BT takes two to four times longer than the review of mammography images. In an effort to reduce the review t

Introduction: Arterial spin labelling (ASL) is a non-invasive magnetic resonance imaging (MRI) technique for assessment of perfusion. ASL uses magnetically labelled blood water as a diffusible endogenous tracer to measure the perfusion of brain tissue, i.e. the cerebral blood flow (CBF). Traditionally, ASL samples images at a specific point in time allowing the CBF to be calculated using a model o

The purpose is to investigate whether the correlation between equity returns and changes in CDS spreads is stronger for sub-investment grade companies than for investment grade companies in the European iTraxx indices.

The thesis is an attempt to investigate the use of “informal justice as a political method” ( or “IRPM” in short) by the two Swedish right-wing organizations “info14/Fria Nationalister” and “Svenska motståndsrörelsen” using the organizations’ own web-published material for the period of 2000-2009, and to put the organizations’ use of “IRPM” into a Swedish empirical context. The thesis goes about

Syftet med vår uppsats är att studera förekomsten och effekterna av fenomenet interlocking directorates (överlappande styrelseuppdrag) i en styrelse inom en kooperativ organisation. Uppsatsens syfte är även att med hjälp av det empiriska underlaget förbättra och anpassa en teoretisk referensram till en kooperativ organisation. I metodkapitlet diskuteras varför vi har valt en abduktiv och kvalitati

This paper investigates if the importance of sunk costs differs between markets with different exchange rate risk. First, it examines the importance of sunk costs on the export participation decision by estimating the effect the previous export status has on the current export decision. Second, it analyses the effects of product-market characteristics on the export participation decision. Third, i

In this thesis I have investigated pauses in writing in word-internal contexts and clause boundaries. I have been looking at the differences between 15-year-olds and adults with dyslexia and been focusing on how many pauses and how much pause time they have in these contexts. People with dyslexia have difficulties coding words, which mean that they are bad spellers and readers. Normally we automat

Studiens syfte var att undersöka varför patienter valt att ensidigt avsluta sitt deltagande i KBT i grupp, vilka förväntningar de avhoppade patienterna hade haft på behandlingen, hur de upplevde behandlingen och om dessa upplevelser var relaterade till avhoppet. Semistrukturerade intervjuer utfördes med sju personer, vilka alla hade hoppat av från KBT-grupper innan behandlingen var slutförd. Reasons behind patients’ decisions to unilaterally terminate Cognitive Behavioral Group Therapy (CBGT), and whether the experience of the therapy was related to the termination of the treatment were examined. In addition to this, the patients’ expectations on the treatment prior to commencement and patients’ experiences of the treatment were examined. Semi-structured interviews were conducted

In this study the efficiency of the Nordic stock markets are tested. The evaluation period is 16 years, between 1995 and 2010. Monthly data on stock returns, D/Y, P/C, P/E, PTBV and EV/EBITDA are used to create six different single sorted portfolios. The portfolio evaluation periods and holding periods are set to six months. Our findings indicate that all of our single sorted portfolios could gene

This study aims to examine the media influence on the general public view of the imprisonment. It also aims to examine if there are any other variables that influence how the law is communicated to the society. This study is about how imprisonment is communicated by the media, but not all imprisonments and not all types of media - it addresses the newspapers report of imprisonment for the crime of

During 2007, a legal reform in Sweden took place, this change led to complications in interpreting the needs of individuals and the application of the laws by the governing social authorities. The aim of the thesis is to explore the underlying norms that influence social workers interpretation of young offenders needs, aged 15 to 17 years, and if the interpretations are consistent. The aim was ach

The Swedish Social Services Act states that certain authorities and their staff have a duty to immediately report to the Social Services if, in the course of their work, they have reason to suspect a child is in need of the protection of the Social Services. The purpose of this study was to examine some of the professional norms within the municipal school when it comes to the duty to report. The