Sökning: "50 MeV electrons"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden 50 MeV electrons.

  1. 1. Biological effects of high energy radiation and ultra high dose rates

    Författare :Björn Zackrisson; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiobiology; 50 MV x-rays; 50 MeV electrons; in vitro; in vivo; RBE; OER; ultra high dose-rate; radiobiological models; model selection; models of stochastic processes;

    Sammanfattning : Recently a powerful electron accelerator, 50 MeV race-track microtron, has been taken into clinical use. This gives the opportunity to treat patients with higher x-ray and electron energies than before. Furthermore, treatments can be performed were the entire fractional dose can be delivered in parts of a second. LÄS MER

  3. 2. Production of photoneutron beams and radionuclides by photonuclear reactions using a 50 MeV racetrack microtron

    Författare :Bo Nordell; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Neutron therapy; Photoneutron spectrum; Bremsstrahlung; Angular distribution; Carbon 11; Iodine 123;

    Sammanfattning : The feasibility of using electrons accelerated by a 50 MeV racetrack microtron to generate a mixed beam of neutrons and photons for radiation therapy and for production of radionuclides has been investigated.To develop target systems for these purposes the angular distribution and yield of bremsstrahlung from different targets have been studied theoretically. LÄS MER

  4. 3. Development of improved radiation therapy techniques using narrow scanned photon beams

    Författare :Björn Andreassen; Anders Brahme; Håkan Danared; Roger Svensson; Antony Lomax; Stockholms universitet; []
    Nyckelord :IMRT; Scanned photon beams; PET-CT treatment verification; Monte Carlo; NATURAL SCIENCES; NATURVETENSKAP; Medical Radiation Physics; medicinsk strålningsfysik;

    Sammanfattning : The present thesis is focused on the development and application of narrow scanned high energy photon beam for radiation therapy. The introduction of physically and biologically optimized intensity modulated radiation therapy (IMRT) requires a flexible and accurate dose delivery method to maximize the treatment outcome. LÄS MER

  5. 4. Electron Transport in Semiconductor Nanowires

    Författare :Mikael Björk; Fasta tillståndets fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; heterostructures; single electron transistors; resonant tunneling; quantum dots; weak antilocalization; Halvledarfysik; field effect transistors; Semiconductory physics; Fysicumarkivet A:2004:Björk; Low-dimensional structures; nanowires; chemical beam epitaxy;

    Sammanfattning : In this thesis, semiconductor nanowires are studied from the point of view of growth and electrical properties. The growth of nanowires is done by chemical beam epitaxy (CBE), an ultra-high vacuum technique allowing a precise control of precursor deposition and low growth rates. LÄS MER

  7. 5. New Efficient Detector for Radiation Therapy Imaging using Gas Electron Multipliers

    Författare :Janina Östling; Mats Danielsson; Anders Brahme; Fabio Sauli; Stockholms universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Portal imaging; Gas Electron Multiplier; Gas detector; Medical engineering; Medicinsk teknik;

    Sammanfattning : Currently film is being replaced by electronic detectors for portal imaging in radiation therapy. This development offers obvious advantages such as on-line quality assurance and digital images that can easily be accessed, processed and communicated. LÄS MER