development of methemoglobin-based biological dosimetry in gamma–irradiated mice

background: a new biological dosimeter based on methemoglobin level was developed in this study. materials and methods: methemoglobin level in erythrocytes from mice subjected to γ rays from a 60co source was detected using the methemoglobin kit. the dose range was from 0.5 to 8 gy and the dose rate was 0.5 gy/min. results: the results demonstrate that methemoglobin level increases with increasing dose. the detection limit based on methemoglobin has a lower limit of dose estimation of about 1 gy. the high levels of methemoglobin are maintained for at least 28 days, and the maximal increase of methemoglobin observed occurs at about 30 min after γ irradiation. the relationship between dosage and the increased methemoglobin level can be expressed by a linear quadratic equation of y = -8.75 x2 + 168.09 x + 32.66, with the correlation coefficient, r, equal to 0.96. the best suggested time for blood collection is up to 1 day after γ irradiation. the doses absorbed by mice as estimated from the use of the dose-response relationship were close to the blind doses of 1, 2, 4 and 8 gy. conclusion: methemoglobin is a quick, simple, and precise biomarker for the early assessment of the absorbed dose in mice.