03/25/2025
By Mark Tries
The Biomedical Engineering and Biotechnology Program invites you to attend a Dissertation Defense by Nada Alsufyani on “Quantification of Biological Response to Low Dose Ionizing Radiation: A Dose-Response Modeling Approach."
Date: April 8, 2025
Time: 2 – 4:30 p.m.
Location: This will be a virtual defense via Zoom. Those interested in attending should contact Nada Alsufyani and committee member Mark Tries at least 24 hours prior to the proposal defense to request access to the meeting.
Committee Chair:
Mark Tries, Ph.D., Associate Professor, Physics and Applied Physics
Committee Members:
Romy Guthier, Ph.D., Assistant Professor, Physics and Applied Physics
Marian Jandel, Ph.D., Associate Professor, Physics and Applied Physics
Abstract:
This dissertation explores the biological effects of low-dose ionizing radiation (LDIR). It investigates the mechanisms underlying adaptive responses that challenge traditional radiation risk models, particularly the linear no-threshold (LNT) model. The research aims to refine the dose-response framework by examining molecular, cellular and epidemiological evidence, specifically focusing on DNA damage response (DDR), DNA repair pathways, immune response and apoptosis. The study identifies key biomarkers involved in radiation-induced adaptive responses, including DNA repair proteins encoded by the protein kinase, DNA-activated, catalytic subunit gene (PRKDC) and antioxidant enzymes like superoxide dismutase (SOD) and catalase (CAT). Experimental findings demonstrate that LDIR activates defense mechanisms, with the most pronounced effects observed in the 1 – 5 mSv dose range. These findings suggest a potential threshold for adaptive responses below which radiation exposure may enhance cellular resistance to subsequent damage. Epidemiological data further support the notion that low-dose environmental and occupational radiation exposures do not consistently correlate with increased cancer risks, further substantiating the concept of radiation hormesis. However, at doses exceeding 20 mSv, a transition to LNT behavior is observed, aligning with the traditional understanding of radiation risk at higher doses. In conclusion, this dissertation contributes to advancing our understanding of the biological effects of LDIR and adopts a refined model of radiation risk that incorporates adaptive responses. The findings provide a foundation for future research in radiation biology, policy development and therapeutic applications, with a focus on personalized approaches to radiation safety and the potential for long-term adaptive effects.
All interested persons are welcome to attend.