Dose response of prematurely condensed chromosome rings after gamma irradiation.

This paper presents a calibration curve for prematurely condensed chromosome rings (PCC-ring) which are scarce in cytogenetic dosimetry; here we analyzed the behavior of the PCC-ring frequency and PCC index after gamma irradiation in the dose interval from 0 to 20 Gy. PCC-rings were induced in lymphocytes with Calyculin A. A total of 5788 PCC cells in G1, G2/M, and M/A stages were analyzed. The best fitting curve between the frequency of PCC ring (Y) and the Dose (D) was obtained with the equation Y = (0.0308 ± 0.0012) D. The distribution of rings by cell followed a Poisson distribution. The PCC index was correlated with radiation dose and decreased in a dose-dependent manner. This PCC-ring dose-effect curve can be used in case of high dose accidental overexposure to gamma radiation, allowing a dose assessment in a reliable way in most of the simulated irradiation analyzed.