EPR dosimetry in chemically treated fingernails

Area of Science:

• Biophysics
• Radiation Dosimetry
• Chemical Analysis

Background:

• Electron Paramagnetic Resonance (EPR) measurements of radiation-induced radicals in human fingernails offer a method for retrospective radiation dose estimation.
• Mechanically induced EPR signals (MIS) and background signals (BKS) can interfere with accurate dose assessment due to overlapping spectral parameters with radiation-induced signals (RIS).

Purpose of the Study:

• To investigate chemical treatments for reducing MIS and BKS in fingernail samples for EPR-based radiation dosimetry.
• To assess the impact of chemical treatment on the accuracy and sensitivity of radiation dose estimation.

Main Methods:

• Human fingernail samples were subjected to various chemical treatments to mitigate interfering EPR signals.
• EPR spectroscopy was used to measure radiation-induced signals (RIS) and assess the reduction of MIS and BKS after treatment.
• Dose-response curves were analyzed before and after chemical treatment.

Main Results:

• A 20-minute treatment with 0.1 M dithiothreitol (DTT) aqueous solution effectively reduced MIS and BKS by a factor of 10.
• This reduction facilitates the potential measurement of doses as low as 1 Gy shortly after irradiation.
• The DTT treatment, while reducing interfering signals, also decreased RIS intensity and altered dose dependence, necessitating calibration curves.

Conclusions:

• Chemical treatment of fingernails with DTT is a promising method to improve the accuracy of EPR-based radiation dosimetry.
• A field-deployable protocol for EPR dosimetry using treated fingernails could aid in the triage of individuals exposed to significant radiation doses.
• Further development is needed to optimize the chemical treatment and calibration for practical application in radiation accident dosimetry.