gamma-h2ax-based dose estimation for whole and partial body radiation exposuregamma-h2ax-based剂量估算对整体和部分的身体辐射.pdfVIP

Gamma-H2AX-Based Dose Estimation for Whole and Partial Body Radiation Exposure 1,2 1 1 Simon Horn *, Stephen Barnard , Kai Rothkamm 1 Health Protection Agency Centre for Radiation, Chemical and Environmental Hazards, Chilton, Oxfordshire, United Kingdom, 2 Queen’s University Belfast Centre for Cancer Research and Cell Biology, Belfast, United Kingdom Abstract Most human exposures to ionising radiation are partial body exposures. However, to date only limited tools are available for rapid and accurate estimation of the dose distribution and the extent of the body spared from the exposure. These parameters are of great importance for emergency triage and clinical management of exposed individuals. Here, measurements of c-H2AX immunofluorescence by microscopy and flow cytometry were compared as rapid biodosimetric tools for whole and partial body exposures. Ex vivo uniformly X-irradiated blood lymphocytes from one donor were used to generate a universal biexponential calibration function for c-H2AX foci/intensity yields per unit dose for time points up to 96 hours post exposure. Foci – but not intensity – levels remained significantly above background for 96 hours for doses of 0.5 Gy or more. Foci-based dose estimates for ex vivo X-irradiated blood samples from 13 volunteers were in excellent agreement with the actual dose delivered to the targeted samples. Flow cytometric dose estimates for X-irradiated blood samples from 8 volunteers were in excellent agreement with the actual dose delivered at 1 hour post exposure but less so at 24 hours post exposure. In partial body exposures, simulated by mixing ex vivo irradiated and unirradiated lymphocytes, foci/intensity distributions were significantly over-dispersed