Sökning: "radiofysik"

Visar resultat 21 - 25 av 69 avhandlingar innehållade ordet radiofysik.

  1. 21. Development of methods and strategies for optimisation of x-ray examinations

    Detta är en avhandling från Göteborgs universitet

    Författare :Jonny Hansson; Göteborgs universitet.; Gothenburg University.; [2019]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; optimisation; visual grading; VGC Analyzer;

    Sammanfattning : 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. LÄS MER

  2. 22. Small-Scale Absorbed Dose Modelling in Selective Internal Radiation Therapy Microsphere Distribution in Normal Liver Tissue

    Detta är en avhandling från Göteborg : University of Gothenburg

    Författare :Jonas Högberg; Göteborgs universitet.; Gothenburg University.; [2015]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; clusters; dosimetry; heterogeneity; liver; microspheres; radioembolisation; simulations; SIRT; surgery; yttrium-90;

    Sammanfattning : Radioembolisation (RE), with yttrium-90 (90Y) labelled microspheres, is an increasingly common treatment method for unresectable liver tumours. The tolerable mean absorbed dose for normal liver (NL) tissue is higher in RE than in External Beam Radiation Therapy (EBRT); absorbed dose heterogeneity is thought to be one important reason, together with a low absorbed dose rate, but the knowledge of microsphere distributions is limited. LÄS MER

  3. 23. Intravoxel incoherent motion modeling - Optimization of acquisition, analysis and tumor tissue characterization

    Detta är en avhandling från Göteborgs universitet

    Författare :Oscar Jalnefjord; Göteborgs universitet.; Gothenburg University.; [2018]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; IVIM; MRI; diffusion; perfusion; cancer;

    Sammanfattning : Intravoxel incoherent motion (IVIM) analysis provides a means to obtain information on diffusion and perfusion from a single MRI sequence. The measurements are completely noninvasive and the results have been shown to be of interest, for example, in oncological applications. LÄS MER

  4. 24. Microdosimetry of radiohalogens in thyroid models

    Detta är en avhandling från Göteborgs universitet

    Författare :Anders Josefsson; Göteborgs universitet.; Gothenburg University.; [2014]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Microdosimetry; radiohalogens; radioiodine; astatine-211; thyroid gland; man; rat; mouse;

    Sammanfattning : The radiohalogens 123I, 124I, 125I, 131I, and 211At are routinely used or proposed for diagnostic and therapeutic purposes. The different characteristics and application areas of these radioiodine isotopes, together with the possibility to bind them to the same carrier molecule, give many advantages, for example, by enabling relevant biodistribution and dosimetric studies important for dose-planning before radionuclide therapy. LÄS MER

  5. 25. Tumour vasculature, oxygenation and radiosensitivity - a numerical modelling study

    Detta är en avhandling från Göteborg : University of Gothenburg

    Författare :Jakob Heydorn Lagerlöf; Göteborgs universitet.; Gothenburg University.; [2014]
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Angiogenesis; Dosimetry; Hypoxia; Modelling; Radionuclide therapy; Radiotherapy; Tumour Control Probability;

    Sammanfattning : This thesis aims to investigate theoretically how parameters such as vessel density, blood oxygenation, blood velocity, spatial oxygen variation along vessels, tissue oxygen consumption and their distributions in uence the radiosensitivity of tumours. Numerical calculations are made in Matlab using voxel-based models. LÄS MER