<p>This research addresses low dose ionizing radiation exposure and risk. While it is well understood that high doses of radiation lead to deleterious health effects, there is controversy surrounding the definitive level of risk associated with exposure to low doses of radiation. These types of low level exposures are relevant to patients undergoing medical imaging procedures. This thesis considers the health effects associated with nuclear medicine, specifically positron emission tomography (PET), with the radiopharmaceutical 2-deoxy-2-(¹⁸F)fluoro-D-glucose(¹⁸F-FDG). These effects were studied in mice to eliminate the high degree of variability among human patients.</p> <p>The early response to various injection activities of ¹⁸F-FDG was first considered in terms of the DNA damage response in the haematopoietic cells of wild-type <em>Trp53+/+</em> mice. The late effects of PET scans with clinically relevant doses of ¹⁸F-FDG, such as carcinogenesis, were evaluated in cancer prone <em>Trp53+/-</em> mice. The role of p53 in the response to low dose radiation was also investigated to explore how short term responses correlate with p53-mediated cancer risk. This work has helped to advance the understanding of low dose radiation biology and the health risks associated with medical imaging procedures.</p> / Doctor of Philosophy (PhD)