Search for dissertations about: "radiation assessment"

Showing result 11 - 15 of 118 swedish dissertations containing the words radiation assessment.

2. 11. Evolutionary ecology of ultraviolet-B radiation stress tolerance in amphibians

   Author : Maarit Pahkala; Trevor Beebee; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; amphibians; anomalies; embryonic development; geographic variation; growth; Rana arvalis; Rana temporaria; survival; UV-B radiation; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; populationsbiologi; Population Biology;

   Abstract : During the last decades many amphibian species and populations have experienced declines and extinctions in different parts of the world. Anthropogenic activities are believed to account for these declines, and one of the hypothesized causes has been the increased level of ultraviolet-B (UV-B) radiation due to depletion of the stratospheric ozone layer. READ MORE

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

   Author : Traimate Sangsuwan; Siamak Haghdoost; Eva Forssell-Aronsson; Stockholms universitet; []
   Keywords : 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;

   Abstract : 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. READ MORE

5. 13. Volumetric assessment of hippocampus and cerebral white matter lesions in structural MRI

   Author : Erik Olsson; Göteborgs universitet; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; structural MRI; white matter lesions; hippocampal volumetry; reliability; mild cognitive impairment; dementia; low dose radiation;

   Abstract : Assessment in structural MRI like hippocampal volumetry and white matter lesion (WML) assessment is receiving widespread attention and recommen-dation as important research and diagnostic tools. The aim in this thesis is to contribute to enhanced reliability and validity in structural MRI assessment. READ MORE

6. 14. On ionising radiation and breast cancer risk

   Author : Anders Mattsson; Karolinska Institutet; Karolinska Institutet; []
   Keywords : ionising radiation; breast cancer induction; cancer induction; risk models; risk modification; pooled analysis; mammmographic screening; gained lost years of life;

   Abstract : Background: It is well known that exposure to ionising radiation increases the risk for breast cancer occurrence. However, better understanding of breast cancer risks in terms of dose-response relationships formulated according to radiobiological target theories, age-at-exposure patterns and temporal dependence are important for the understanding of the underlying biological mechanism of radiation carcinogenesis as well as for the concern about possible risks associated with the very low doses received from routine mammographic screening. READ MORE

7. 15. Evaluation of image quality and diagnostic accuracy in breast tomosynthesis. Comparison with digital mammography and estimates of radiation risk

   Author : Tony Svahn; Malmö Medicinsk strålningsfysik; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; diagnostic accuracy; breast tomosynthesis BT ; digital mammography DM ; average glandular dose AGD ; receiver operating characteristics ROC ; risk assessment; search-model SM ; proper ROC PROPROC ;

   Abstract : Recent advances in the digital detector technology have paved the way for modalities such as two-dimensional digital mammography (DM) and three-dimensional breast tomosynthesis (BT). In this work, experimental studies were conducted to investigate the influence of reducing the average glandular dose (AGD) on detection of simulated lesions in DM and to compare the diagnostic accuracy of BT and DM. READ MORE