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 60 Co 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 detec%on limit based on methemoglobin has a lower limit of dose es%ma%on 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 a+er γ irradia%on. The rela%onship between dosage and the increased methemoglobin level can be expressed by a linear quadra%c equa%on of y = 8.75 x 2 + 168.09 x + 32.66, with the correla%on coef fi cient, r, equal to 0.96. The best suggested %me for blood collec%on is up to 1 day a+er γ irradia%on. The doses absorbed by mice as es%mated from the use of the dose-response rela%onship 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.