Sökning: "Radiation field"

Visar resultat 1 - 5 av 441 avhandlingar innehållade orden Radiation field.

  1. 1. 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 :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

  3. 2. Cellular effects of ionizing radiation : Relevant for understanding cancer risk after medical and environmental radiation exposures

    Författare :Pamela Chiaka Akuwudike; Andrzej Wojcik; Lovisa Lundholm; Kerstin Borgmann; Stockholms universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiation; DNA damage; radiation-induced carcinogenesis; second primary cancer; cisplatin chemoradiotherapy; dose fractionation; low dose; low dose rate; dose and dose rate effectiveness factor DDREF ; molekylär biovetenskap; Molecular Bioscience;

    Sammanfattning : Radiation-induced cancers are stochastic and delayed effects of exposure to ionizing radiation. The dose-response relationship for radiation-induced cancers at both low dose/low dose rates and high doses (doses encountered during radiotherapy) remains unclear. LÄS MER

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

    Författare :Lennart Olofsson; Mikael Karlsson; Magnus Karlsson; Björn Zackrisson; Erik Traneus; Umeå universitet; []
    Nyckelord :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

  5. 4. Single-photon multiple ionisation of atoms and molecules investigated by coincidence spectroscopy : Site-specific effects in acetaldehyde and carbon dioxide

    Författare :Sergey Zagorodskikh; Raimund Feifel; Vitali Zhaunerchyk; Melanie Mucke; Maria Novella Piancastelli; Tom Field; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; acetaldehyde; carbon dioxide; xenon; electron correlation; double ionisation; triple ionisation; core-valence ionisation; site-specific Auger decay; multiple Auger decay; branching ratios; site-specific photodissociation; molecular rearrangement; time-of-flight multi-electron-ion coincidence spectroscopy; synchrotron radiation; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : In this thesis, multiple ionisation processes of free atoms and molecules upon single photon absorption are studied by means of a versatile multi-electron-ion coincidence spectroscopy method based on a magnetic bottle, primarily in combination with synchrotron radiation. The latter offered the possibility to access not only valence but also core levels, revealing processes, which promote the target systems into different charge states. LÄS MER

  7. 5. Modern Computational Physical Chemistry : An Introduction to Biomolecular Radiation Damage and Phototoxicity

    Författare :Jorge Llano; Leif A. Eriksson; Ulf Ryde; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; statistical mechanics; biophysical chemistry; interface; surface thermodynamics; bioelectrochemistry; ionizing radiation; radiation therapy; condensed matter; computational chemistry; nucleic acids; radiation damage; electrode potential; electronic transport; photochemistry; strand break; photodynamic action; cytostatic; solvation; solvated electron; absolute potential; chemical potential; Biologi; Biology; Biologi;

    Sammanfattning : The realm of molecular physical chemistry ranges from the structure of matter and the fundamental atomic and molecular interactions to the macroscopic properties and processes arising from the average microscopic behaviour.Herein, the conventional electrodic problem is recast into the simpler molecular problem of finding the electrochemical, real chemical, and chemical potentials of the species involved in redox half-reactions. LÄS MER