Sökning: "radiation dose"

Visar resultat 1 - 5 av 349 avhandlingar innehållade orden radiation dose.

  1. 1. Dose painting : Can radiotherapy be improved with image driven dose-responses derived from retrospective radiotherapy data?

    Författare :Eric Grönlund; Anders Ahnesjö; Silvia Johansson; Daniela Thorwarth; Uppsala universitet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiotherapy; functional imaging; dose painting; dose painting by numbers; robust optimization; Medicinsk radiofysik; Medical Radiophysics;

    Sammanfattning : The main aim of curative radiotherapy for cancer is to prescribe and deliver doses that eradicate the tumor and spare the normal healthy tissues. Radiotherapy is commonly performed by delivering a homogeneous radiation dose to the tumor. LÄS MER

  3. 2. Energy and intensity modulated radiation therapy with electrons

    Författare :Lennart Olofsson; Mikael Karlsson; Magnus Karlsson; Björn Zackrisson; Erik Traneus; Umeå universitet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiation sciences; Radiation therapy; Conformal therapy; IMRT; Electrons; Electron treatment head; Electron MLC; Bremsstrahlung reduction; Integral dose; Penumbra; Output factor; Strålningsvetenskap; Radiation biology; Strålningsbiologi; radiofysik; radiation physics;

    Sammanfattning : In recent years intensity modulated radiation therapy with photons (xIMRT) has gained attention due to its ability to reduce the dose in the tissues close to the tumour volume. However, this technique also results in a large low dose volume. LÄS MER

  4. 3. The microdosimetric variance-covariance method used for beam quality characterization in radiation protection and radiation therapy

    Författare :Jan Erik Lillhök; Lennart Lindborg; Bernd Grosswendt; Stockholms universitet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; ionizing radiation; radiation quality; radiation protection; radiation therapy; microdosimetry; nanodosimetry; variance-covariance method; Radiological physics; Radiofysik; medicinsk strålningsfysik; Medical Radiation Physics;

    Sammanfattning : Radiation quality is described by the RBE (relative biological effectiveness) that varies with the ionizing ability of the radiation. Microdosimetric quantities describe distributions of energy imparted to small volumes and can be related to RBE. LÄS MER

  5. 4. CT Urography : Efforts to Reduce the Radiation Dose

    Författare :Pär Dahlman; Anders Magnusson; Anders Sundin; Uppsala universitet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Urinary tract malignancy; renal cell carcinoma; urography; x-ray computed tomography; radiation dosage; dose escalation; hematuria diagnosis; Diagnostic radiology; Diagnostisk radiologi; Radiology; Radiologi;

    Sammanfattning : Computed tomography urography (CTU) is today the imaging method used to investigate patients with suspected urinary tract malignancy, replacing the old imaging method intravenous pyelography (IVP) about a decade ago. The downside of this shift was that the effective radiation dose to the examined patient was eight times higher for CTU compared to IVP. LÄS MER

  7. 5. Short and long-term effects of exposure to low dose and low dose rate of gamma radiation : using in vitro and in vivo models

    Författare :Traimate Sangsuwan; Siamak Haghdoost; Eva Forssell-Aronsson; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Low dose; Low dose rate; High dose rate; Ionizing radiation; Adaptive response; Senescence; Premature senescence; Oxidative stress; Drosophila embryo; Mutation; DNA repair; molekylär biovetenskap; Molecular Bioscience;

    Sammanfattning : Assessment of human health risks from exposure to ionizing radiation (IR) is mainly based on the extrapolation of results from epidemiological studies on populations exposed to relatively high doses and often at high dose rates (HDR). Risk estimates after exposure to low doses and in particular at low dose rates (LDR) remain controversial due to a lack of epidemiological evidence. LÄS MER