Search for dissertations about: "radiofysik"

Showing result 6 - 10 of 106 swedish dissertations containing the word radiofysik.

  2. 6. Contributions to quantitative dynamic contrast-enhanced MRI

    Author : Anders Garpebring; Mikael Karlsson; Ronnie Wirestam; Nils Östlund; Jón Hauksson; Steven Sourbron; Umeå universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dynamic contrast-enhanced MRI; quantitative imaging; parameter estimation; uncertainty estimation; arterial input function; radiofysik; radiation physics;

    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. 7. Quantitative methods for tumor imaging with dynamic PET

    Author : Ida Häggström; Anne Larsson; Mikael Karlsson; Lennart Johansson; Jens Sörensen; Magnus Dahlbom; Umeå universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Dynamic positron emission tomography; PET; tumor imaging; compartment modeling; Monte Carlo; radiofysik; radiation physics;

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

    Author : Adam Johansson; Tufve Nyholm; Karlsson Mikael; James Balter; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; magnetic resonance imaging; computed tomography substitute; ultrashort echo time; parallel imaging; radial imaging; radiofysik; radiation physics;

    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

  6. 9. Integration of MRI into the radiotherapy workflow

    Author : Joakim Jonsson; Tufve Nyholm; Mikael Karlsson; Magnus Karlsson; Uulke van der Heide; Umeå universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; magnetic resonance imaging; radiotherapy; treatment planning; image registration; workflow; radiofysik; radiation physics;

    Abstract : The modern day radiotherapy treatments are almost exclusively based on computed tomography (CT) images. The CT images are acquired using x-rays, and therefore reflect the radiation interaction properties of the material. READ MORE

  7. 10. Corrections for improved quantitative accuracy in SPECT and planar scintigraphic imaging

    Author : Anne Larsson; Lennart Johansson; Katrine Åhlström Riklund; Bertil Axelsson; Umeå universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Quantitative SPECT; scintigraphic imaging; attenuation correction; scatter correction; collimator-detector response; septal penetration; background correction; Monte Carlo simulation; Radiological physics; Radiofysik;

    Abstract : A quantitative evaluation of single photon emission computed tomography (SPECT) and planar scintigraphic imaging may be valuable for both diagnostic and therapeutic purposes. For an accurate quantification it is usually necessary to correct for attenuation and scatter and in some cases also for septal penetration. READ MORE