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Low Dose Rate

Although the health risks of exposure to high doses of radiation at high dose rates during a nuclear or a radiological disaster are well recognized, much research remains to be done to establish the role of dose rate, particularly at low dose rates. To date we have employed metabolomic and bioinformatics approaches to study the unique effects of dose rate on the urinary excretion of metabolites in mice exposed to external beam irradiation at the low dose rate (LDR) of 0.00309 Gy/min compared to high dose rate (HDR). The mice were exposed to the total dose of 1.1 Gy and 4.45 Gy at both dose rates. We took advantage of the high resolving power of ultra-performance liquid chromatography (UPLC) and the high sensitivity of time-of-flight mass spectrometry (TOFMS) to determine the changes in the urinary metabolome of mice exposed to 4.45 Gy and 1.1 Gy at LDR compared to mice exposed to the same doses at HDR.

The results of this study revealed that exposure to external beam γ-irradiation perturbed energy metabolism, fatty acid oxidation, and amino acid metabolism independent of dose rate. Dose rate is speculated to modulate the magnitude of metabolic perturbations and the targets within metabolic pathways.

Future studies will probe intermediate, higher and lower dose rates with the aim of refining these signatures of effects over a wider range of dose rates.

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Center for High-Throughput Minimally-Invasive Radiation Biodosimetry