Physically-based biodosimetry using in vivo EPR of teeth in patients undergoing total body irradiation

Abstract

Purpose: The ability to estimate individual exposures to radiation following a large attack or incident has been identified as a necessity for rational and effective emergency medical response. In vivo electron paramagnetic resonance (EPR) spectroscopy of tooth enamel has been developed to meet this need.

Materials and methods: A novel transportable EPR spectrometer, developed to facilitate tooth dosimetry in an emergency response setting, was used to measure upper incisors in a model system, in unirradiated subjects, and in patients who had received total body doses of 2 Gy.

Results: A linear dose response was observed in the model system. A statistically significant increase in the intensity of the radiation-induced EPR signal was observed in irradiated versus unirradiated subjects, with an estimated standard error of dose prediction of 0.9 ± 0.3 Gy.

Conclusions: These results demonstrate the current ability of in vivo EPR tooth dosimetry to distinguish between subjects who have not been irradiated and those who have received exposures that place them at risk for acute radiation syndrome. Procedural and technical developments to further increase the precision of dose estimation and ensure reliable operation in the emergency setting are underway. With these developments EPR tooth dosimetry is likely to be a valuable resource for triage following potential radiation exposure of a large population.

Keywords:

• electron paramagnetic resonance (EPR)
• biodosimetry
• triage

Acknowledgements

The authors would especially like to thank the volunteers and patients who made this research possible. We would also like to acknowledge the wider team of engineers who have assisted in the development of the in vivo tooth dosimetry instrument, including Tim Raynolds, Maciej Kmiec, Oleg Grinberg, and Kai-Ming Lo and Piotr Starewicz at Resonance Research Inc. Clinical studies were facilitated through collaboration with members of the Sections of Hematology/Oncology and Radiation Oncology at the Dartmouth Hitchcock Medical Center, including coordination by Bonny Wood, and Lynn Root, RN and Idalina Williams, RN. This research was supported by the NIH-NIAID Centers for Medical Countermeasures Against Radiation (CMCR) grants U19-AI-06773, within the University of Rochester Center for Biophysical Assessment and Risk Management Following Irradiation (CBARMFI), and U19-AI-91173 as the Dartmouth Physically-Based Biodosimetry Center for Medical Countermeasures against Radiation (Dart-Dose CMCR). Commercial development of the technology by Clin-EPR, LLC is supported by a Phase I SBIR (R43-AI-081495) also through NIAID.

Declaration of interest:

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.