Gamma-H2AX-based dose estimation for whole and partial body radiation exposure

Area of Science:

• Radiation Biology
• Biodosimetry
• Molecular Biology

Background:

• Partial body radiation exposure is common, but tools for rapid dose assessment are limited.
• Accurate dose distribution and extent of exposure are crucial for emergency triage and clinical management.
• Existing biodosimetric tools lack speed and precision for partial body exposures.

Purpose of the Study:

• To evaluate gamma-H2AX immunofluorescence (microscopy and flow cytometry) as rapid biodosimetric tools for whole and partial body radiation exposures.
• To establish a universal calibration function for gamma-H2AX foci yields.
• To assess the utility of dispersion analysis for partial body exposure scenarios.

Main Methods:

• Generated a universal biexponential calibration function for gamma-H2AX foci/intensity yields using ex vivo X-irradiated blood lymphocytes.
• Compared microscopy and flow cytometry for dose estimation in uniformly and partially irradiated blood samples from volunteers.
• Utilized the zero contaminated Poisson test for analyzing dispersion in partial body exposure simulations.

Main Results:

• Gamma-H2AX foci levels remained elevated for 96 hours post-exposure at doses ≥ 0.5 Gy.
• Foci-based dose estimates showed excellent agreement with actual doses for whole-body exposures.
• Dispersion analysis of foci/intensity distributions accurately determined irradiated fraction size and dose in simulated partial body exposures.

Conclusions:

• Gamma-H2AX analysis of lymphocytes provides rapid and accurate whole-body radiation dose assessment.
• Dispersion analysis of gamma-H2AX foci/intensity distributions is effective for determining partial body doses and irradiated fraction.
• These methods enhance capabilities for emergency response and clinical management of radiation incidents.