Sökning: "radiation dose"

Visar resultat 6 - 10 av 399 avhandlingar innehållade orden radiation dose.

1. 6. CT Urography : Efforts to Reduce the Radiation Dose

   Författare :Pär Dahlman; Anders Magnusson; Anders Sundin; Uppsala universitet; []
   Nyckelord :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; Radiologi; Radiology;

   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

3. 7. 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 :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

4. 8. Studies on the Gamma Radiation Environment in Sweden with Special Reference to 137Cs

   Författare :Sara Almgren; Göteborgs universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; gamma radiation; caesium; 137Cs; deposition; migration; precipitation; in situ; CDE; NWF; Chernobyl; soil sampling; field measurements; dose measurements; dose rate; TLD; natural radiation; Kriging;

   Sammanfattning : Gamma radiation in the environment today mainly originates from naturally occurring radionuclides, but anthropogenic radionuclides, such as 137Cs, contribute in some areas. In order to assess population exposure in case of fallout from nuclear weapons (NWF) or accidents, knowledge and monitoring of external gamma radiation and radionuclide concentrations in the environment is important. LÄS MER

5. 9. Evaluation of absorbed dose and image quality in mammography

   Författare :Bengt Hemdal; Malmö Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; optically stimulated luminescence; radioluminescence; in vivo dosimetry; dose reduction; dose protocol; average glandular dose; absorbed dose; Breast cancer; mammography; Monte Carlo; image quality; image quality criteria; contrast-detail phantom;

   Sammanfattning : Mammography refers to the X-ray examination of the human breast, and is considered the single most important diagnostic tool in the early detection of breast cancer, which is by far the most common cancer among women. There is good evidence from clinical trials, that mammographic screening can reduce the breast cancer mortality with about 30%. LÄS MER

7. 10. On the use of radiography and radiation dose consideration in orthodontic treatment

   Författare :Christina Stervik; Göteborgs universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; effective dose; errors; estimated risk; intra-oral radiograph; organ dose; orthodontic treatment; orthodontists; panoramic image; questionnaires; radiation doses;

   Sammanfattning : The aims of this thesis were to analyse the use of radiography and radiation risk associated with orthodontic treatment. Study I measured absorbed doses to radiosensitive organs in the head and neck in an anthropomorphic phantom head using thermo¬luminescent dosimeters (TLDs) from digital intra-oral and panoramic radiography. LÄS MER