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Visar resultat 1 - 5 av 2047 avhandlingar som matchar ovanstående sökkriterier.

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. Colorectal cancer and radiation response : The role of EGFR, AKT and cancer stem cell markers

   Författare :Sara Häggblad Sahlberg; Bo Stenerlöw; Bengt Glimelius; Marika Nestor; Torgny Stigbrand; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; colorectal cancer; radiation; AKT; EGFR; cancer stem cells; CD133; CD44; Biomedical Radiation Science; Biomedicinsk strålningsvetenskap; Biologi med inriktning mot molekylär cellbiologi; Biology with specialization in Molecular Cell Biology;

   Sammanfattning : The primary treatment for colorectal cancer is surgery. Radiotherapy and chemotherapy, sometimes combined, are also frequently used to diminish recurrence risk. In response to radiation exposure, several cellular signaling cascades are activated to repair DNA breaks, prevent apoptosis and to keep the cells proliferating. LÄS MER

7. 5. Accurate description of heterogeneous tumors for biologically optimized radiation therapy

   Författare :Johan Nilsson; Bengt Lind; Anders Brahme; Margareta Edgren; Søren Bentzen; Stockholms universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; heterogeneous tumors; radiation therapy; biological optimization; tumor hypoxia; effective radiation sensitivity; effective radiation resistance; Radiation biology; Strålningsbiologi;

   Sammanfattning : In this thesis, a model of tissue oxygenation is presented, that takes into account the heterogeneous nature of tumor vasculature. Even though the model is rather simple, the resulting oxygen distributions agree very well with clinically observed oxygen distributions for most tumors and healthy normal tissues. LÄS MER