Sökning: "Anders Ahnesjö"

Visar resultat 11 - 14 av 14 avhandlingar innehållade orden Anders Ahnesjö.

  1. 11. Developing and evaluating dose calculation models for verification of advanced radiotherapy

    Författare :Jörgen Olofsson; Mikael Karlsson; Anders Ahnesjö; Crister Ceberg; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiation therapy; high-energy photons; dose calculation; multi-source model; pencil kernel; uncertainties; action levels; Radiological physics; Radiofysik;

    Sammanfattning : A prerequisite for modern radiotherapy is the ability to accurately determine the absorbed dose (D) that is given to the patient. The subject of this thesis has been to develop and evaluate efficient dose calculation models for high-energy photon beams delivered by linear accelerators. LÄS MER

  3. 12. Probabilistic treatment planning based on dose coverage : How to quantify and minimize the effects of geometric uncertainties in radiotherapy

    Författare :David Tilly; Anders Ahnesjö; Erik Grusell; Uwe Oelfke; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Radiotherapy; treatment simulation; probabilistic planning; dose calculation; probabilistic optimization; statistical shape model; Medicinsk radiofysik; Medical Radiophysics;

    Sammanfattning : Traditionally, uncertainties are handled by expanding the irradiated volume to ensure target dose coverage to a certain probability. The uncertainties arise from e.g. the uncertainty in positioning of the patient at every fraction, organ motion and in defining the region of interests on the acquired images. LÄS MER

  4. 13. Micro/nanometric Scale Study of Energy Deposition and its Impact on the Biological Response for Ionizing Radiation : Brachytherapy radionuclides, proton and carbon ion beams

    Författare :Fernanda Villegas Navarro; Anders Ahnesjö; Carmen Villagrasa; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Ionizing radiation; Monte Carlo track structure code; Microdosimetric spread; Energy deposition clustering; RBE; Medicinsk radiofysik; Medical Radiophysics;

    Sammanfattning : Research in radiotherapy for cancer treatment focuses on finding methods that can improve the compromise between tumour cell inactivation versus damage to the surrounding healthy tissue. As new radiation modalities such as proton therapy become accessible for everyday clinical practice, a better understanding of the variation in biological response of the tumour and healthy tissues would improve treatment planning to achieve optimal outcome. LÄS MER

  5. 14. Patient Positioning in Radiotherapy Using Body Surface Scanning

    Författare :Kenneth Wikström; Anders Ahnesjö; Sven Bäck; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiotherapy; positioning; body surface; laser scanning; cancer; SGRT; ITV; lung cancer; surrogate; tumour motion; 4DCT; Medicinsk radiofysik; Medical Radiophysics;

    Sammanfattning : External radiotherapy uses ionising radiation to damage the DNA of the tumour cells and thereby inhibit their uncontrolled proliferation. The technical development regarding imaging and visualisation for radiotherapy has increased considerably during the last decades. LÄS MER