Search for dissertations about: "radiofysik"

Showing result 1 - 5 of 147 swedish dissertations containing the word radiofysik.

  1. 1. Ion recombination in liquid ionization chambers development of an experimental method to quantify general recombination

    University dissertation from Umeå : Umeå universitet

    Author : Jonas Andersson; Umeå universitet.; [2013]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; General recombination; initial recombination; liquid ionization chamber; radiation dosimetry; radiofysik; radiofysik;

    Abstract : An experimental method (the two-dose-rate method) for the correction of general recombination losses in liquid ionization chambers has been developed and employed in experiments with different liquids and radiation qualities. The method is based on a disassociation of initial and general recombination, since an ionized liquid is simultaneously affected by both of these processes. READ MORE

  2. 2. Applications of statistical methods in quantitative magnetic resonance imaging

    University dissertation from Umeå : Umeå universitet

    Author : Patrik Brynolfsson; Umeå universitet.; [2017]
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Quantitative imaging; tumor imaging; dynamic contrast-enhanced MRI; diffusion weighted MRI; texture analysis; radiofysik; radiofysik;

    Abstract : Magnetic resonance imaging, MRI, offers a vast range of imaging methods that can be employed in the characterization of tumors. MRI is generally used in a qualitative way, where radiologists interpret the images for e.g. diagnosis, follow ups, or assessment of treatment response. READ MORE

  3. 3. Contributions to quantitative dynamic contrast-enhanced MRI

    University dissertation from Umeå : Umeå Universitet

    Author : Anders Garpebring; Umeå universitet.; [2011]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dynamic contrast-enhanced MRI; quantitative imaging; parameter estimation; uncertainty estimation; arterial input function; radiofysik; radiofysik;

    Abstract : Background: Dynamic contrast-enhanced MRI (DCE-MRI) has the potential to produce images of physiological quantities such as blood flow, blood vessel volume fraction, and blood vessel permeability. Such information is highly valuable, e.g., in oncology. READ MORE

  4. 4. Quantitative methods for tumor imaging with dynamic PET

    University dissertation from Umeå : Umeå Universitet

    Author : Ida Häggström; Umeå universitet.; [2014]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Dynamic positron emission tomography; PET; tumor imaging; compartment modeling; Monte Carlo; radiofysik; radiofysik;

    Abstract : There is always a need and drive to improve modern cancer care. Dynamic positron emission tomography (PET) offers the advantage of in vivo functional imaging, combined with the ability to follow the physiological processes over time. READ MORE

  5. 5. Magnetic resonance imaging with ultrashort echo time as a substitute for X-ray computed tomography

    University dissertation from Umeå : Umeå universitet

    Author : Adam Johansson; Umeå universitet.; [2014]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; magnetic resonance imaging; computed tomography substitute; ultrashort echo time; parallel imaging; radial imaging; radiofysik; radiofysik;

    Abstract : Radiotherapy dose calculations have evolved from simple factor based methods performed with pen and paper, into computationally intensive simulations based on Monte Carlo theory and energy deposition kernel convolution.Similarly, in the field of positron emission tomography (PET), attenuation correction, which was originally omitted entirely, is now a crucial component of any PET reconstruction algorithm. READ MORE