Fingernail electron paramagnetic resonance dosimetry protocol for localized hand exposure accident

Exposure to ionizing radiation induces free radicals in human nails. These free radicals generate a radiation-induced signal (RIS) in electron paramagnetic resonance (EPR) spectroscopy. Compared with the RIS of tooth enamel samples, that in human nails is more affected by moisture and heat, but has the advantages of being sensitive to radiation and easy to collect. The fingernail as a biological sample is applicable in retrospective dosimetry in cases of localized hand exposure accidents. In this study, the dosimetric characteristics of fingernails were analyzed in fingernail clippings collected from Korean donors. The dose response, fading of radiation-induced and mechanically induced signals, treatment method for evaluation of background signal, minimum detectable dose, and minimum detectable mass were investigated to propose a fingernail-EPR dosimetry protocol. In addition, to validate the practicality of the protocol, blind and field experiments were performed in the laboratory and a non-destructive testing facility. The relative biases in the dose assessment result of the blind and field experiments were 8.43% and 21.68% on average between the reference and reconstructed doses. The results of this study suggest that fingernail-EPR dosimetry can be a useful method for the application of retrospective dosimetry in cases of radiological accidents.(c) 2022 Korean Nuclear Society, Published by Elsevier Korea LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Exposure to ionizing radiation generates free radicals in human nails, which can be detected by radiation-induced signal (RIS) in electron paramagnetic resonance (EPR) spectroscopy. Fingernails are more affected by moisture and heat compared to tooth enamel samples, but they are sensitive to radiation and easy to collect. This study analyzed the dosimetric characteristics of fingernails and proposed a fingernail-EPR dosimetry protocol for retrospective dosimetry in localized hand exposure accidents. The practicality of the protocol was validated through blind and field experiments, showing promising results for the application of fingernail-EPR dosimetry in radiological accidents.