Development of serum copper-based biological dosimetry in whole body gamma irradiation of mice.

A new biological dosimeter based on serum copper has been developed. Serum copper in mice subjected to a Co-60 source at a dose rate of 0.5 Gy min(-1) was detected using the bis(cyclohexanone) oxaldihydrazone colorimetric method. The dose range was from 0.5-7 Gy. The results demonstrate that serum copper decreases with increasing dose. A linear dose response is obtained. The detection limit based on serum copper is the same as that with the lower limit of dose assessment; i.e., about 1 Gy. The decrease in serum copper continues until the 28th day after gamma radiation. The absorbed doses in mice assessed using the linear curve are close to "blind" doses of 4 and 6 Gy. Therefore, serum copper is a quick, simple, and accurate biomarker for early assessment of radiation exposure of mice in the range of 0.5-7 Gy.