Effects of Different Premature Chromosome Condensation Method on Dose-curve of ~(60)Co γ-Ray

Objective To study the effect of traditional method and improved method of the premature chromosome condensation(PCC) on the dose-effect curve of 60Co γ ray,for choosing the rapid and accurate biological dose estimating method for the accident emergency.Methods Collected 3 healthy male cubits venous blood(23 to 28 years old),and irradiated by 0,1.0,5.0,10.0,15.0,20.0 Gy 60Co γ ray(absorbed dose rate:0.635 Gy/min).Observed the relation of dose-effect curve in the 2 incubation time(50 hours and 60 hours) of the traditional method and improved method.Used the dose-effect curve to verify the esposure of 10.0 Gy(absorbed dose rate:0.670 Gy/min).Results ①In the traditional method of 50-hour culture,the PCC cell count in 15.0 Gy and 20.0 Gy was of no statistical significance.But there were statistical significance in the traditional method of 60-hours culture and improved method(50-hour culture and 60-hour culture).Used the last 3 culture methods to make dose curve.②In the above 3 culture methods,the related coefficient between PCC ring and exposure dose was quite close(all of more than 0.996,P0.01),the linear regression equation was established and the correlation index was quite close,the dose-effect curve was fitting the linear model.But there were no statistical significance among regression coefficient(P0.05),the morphology of regression straight lines almost overlap.③Used the above 3 dose-effect curves to estimate the irradiation results(10.0 Gy),the error was less than or equal to 8%,all of them were within the allowable range of the biological experiment(15%).Conclusion The 3 dose-effect curves of the above 3 culture methods can apply to biological dose estimating of large doses of ionizing radiation damage.Especially the improved method of 50-hour culture,it is much faster to estimate and it should be regarded as the first choice in accident emergency.