Scoring rings in the cell fusion-induced premature chromosome condensation (PCC) assay for high dose radiation exposure estimation after gamma-ray exposure.

Purpose: This study aimed to construct a calibration curve for high-dose exposure using cell fusion-induced premature chromosome condensation (PCC). Some of the associated practicalities and methodological details were also investigated. Materials and methods: Peripheral blood from two donors was used. PCC mediated by fusing mitotic CHO cells with interphase lymphocytes was carried out. Lymphocytes were irradiated with 60Co (0-20 Gy) and held at 37 °C for 24 h post exposure. Results: The protocol for PCC induction was effective at all doses and the number of rings increased with increasing dose. No significant difference was found between the donors (p = .896) and data were pooled. Ring aberration frequencies followed a Poisson distribution and the dose-response relationship favored a linear fitting: Y = 0.0007(±0.0004)+0.0186(±0.001)×D. Blind tests showed that the estimated doses were all within the 95% confidence limits of the delivered doses. This study has shown that it is valid to score only 100 cells per sample in a triage mode for doses above 5 Gy and that it is valid to score only hollow rings to reduce the scoring time. Conclusion: Scoring rings in cell fusion-induced PCC assay can be a feasible and fast approach for the analysis of high-dose exposures.