Honoring Miral Dizdaroglu: the dizdar, a lesion-resolved unit for quantifying radiation-induced DNA damage.

PURPOSE: We propose a unit-the dizdar, Dz-defined as the number of lesions per kilogram of DNA. In biomedical and exposure settings, this would provide a common unit for reporting irradiation-induced lesion burdens, complementing absorbed dose. The dizdar is named in honor of Dr. Miral Dizdaroglu, whose pioneering work established rigorous chemical identification and quantitative measurement of oxidative and radiation-induced DNA lesions. We give an overview of the foundation he laid for DNA damage and discuss how this naturally leads to a vector of quantities, D=(Dz)z, with, Dz = NznDNA indexed by lesion class z. This complements absorbed dose (Gy) by capturing the primary molecular drivers of biological outcomes. Building on Miral's legacy and on this concept of lesion quantification, we are developing a new methodology that uses nanopore resistive pulse sensing to rapidly and quantitatively measure DNA lesions.

CONCLUSION: This approach provides a basis for time-dependent measurements of DNA damage and, with further validation, could help assess repair dynamics and the biological effects of different radiation delivery modalities. Advances in single-molecule methods, uncertainty quantification, & calibration can help bridge dosimetry to biological effectiveness via the dizdar, quantifying one link in the stochastic chain that leads to cell death and cancer. In turn, this may deepen our understanding of radiation-induced DNA damage and have applications in emergency response, radiation processing, space research, & cancer treatment.