Retrospective Reconstruction of Biological Dose in Early Radiation Accident Cases Through Chromosomal Translocations Analysis Using G-Banding

OBJECTIVE: To analyze stable chromosomal aberrations and reconstruct the biological dose in 6 victims of the Henan "4.26" 60Co radiation accident, 9 and 20 years after irradiation. METHODS: G-banding chromosomal specimens were prepared using conventional culture and trypsin digestion methods. Stable chromosomal aberrations in six victims were analyzed with an automated chromosome scanning system and karyotype analysis software to estimate the biological dose based on chromosomal translocation indicators. RESULTS: The number of stable chromosomal aberrations per cell at the two follow-ups demonstrated a significant dose-effect relationship with the radiation dose. A noticeable increase in translocations per cell was observed 20 years after the accident compared with 9 years. At 9 years post-irradiation, the mean absorbed doses for four cases, estimated from translocations per cell, were similar to those estimated from dicentrics plus rings at 5 days post-irradiation, while a slight decrease was observed in one case. At 20 years post-irradiation, the mean absorbed dose based on translocations per cell for five cases was essentially the same as the dose estimated from dicentrics plus rings at 5 days post-irradiation. CONCLUSION: The G-banding approach, characterized by its simplicity and low cost, is feasible for analyzing chromosomal translocations and retrospectively reconstructing the biological dose of early radiation accidents.