ABSTRACT
Objective To explore the natural attenuation pattern of three biological dose estimation indexes in vivo by investigating the effect on biological dosimetry of peripheral blood sampling at different time points from the victim partially exposed to 192Ir radiation source at5.7 accident in Nanjing.Methods Peripheral blood of the patient was collected on days 5,40 and 280 after exposure,respectively.The yields of dicentrics plus rings chromosomes (dic + r),cytokinesis-block micronuclei (CBMN) and nucleoplasmic bridge + fusion + horse shoe + circular(NPB + FHC) were analyzed.The dynamic reduction and dose estimation were both observed using the biomarkers mentioned above after exposure.Results Compared to the estimates on days 5 after exposure,the dose values estimated on days 40 and 280 decreased by 34％ and 49％ fordic + r method,48％ and 79％ for the CBMN assay,and 48％ and 75％ for NPN + FHC method,respectively.Conclusions Three biological dose estimation indexes show a progressive decrease in vivo,with the half-life of dic + r/cell being 40 days.The doses estimated using these three indexes on days 40 after exposure showed a relative deviation more than 20％ compared with those on days 5 after exposure.
ABSTRACT
Objective To use three different methods in attempt to estimate the biological dose of the patient partially exposed to 192Ir source at5.7 accident in Nanjing,so as to provide dosimetric information for clinical remedy of exposed patients in the emergency of a nuclear accident.Methods Peripheral blood samples were collected on days 5 after exposure.The biological dose was estimated by the yields of dicentrics plus rings ( dic + r),cytokinesis-block micronuclei (CBMN) assay and nucleoplasmic bridge plus FHC (NPB + FHC).The homogeneity of radiation exposure was examined by Poisson distribution of dicentrics.Results By using three different methods,the whole body equivalent dose was dic + r estimated to be 1.51 Gy (95％ CI 1.40-1.61),1.47 Gy (95％ CI 1.36-1.60) by CBMN and 1.30 Gy (95％ CI 1.00-1.60) by NPB + FHC,respectively.A non-poisson distribution was also detected,suggesting partial body radiation exposure.Conclusions The estimated whole body equivalent dose ot a non-uniform radiation exposure was consistent with clinical diagnosis,suggesting that the yields ofdic + r,CBMN,as well as NPB + FHC,are efficient approaches to the estimation of biological doses.
ABSTRACT
Objective To make a rapid dose estimation for a patient exposed locally to high dose radiation exposure in early stage of 5.7 192Ir source accident in Nanjing.Methods Based on source parameters,exposure pattern,and time duration,the doses were estimated using MCNP simulations with the aid of the proper East Asia adult male voxel phantom and main physiological parameters of the exposed patient.Result Absorbed doses to 16 organs or tissues were estimated to be in the range 0.03 to 9.16 Gy.Also,the iso-dose curves for the skin of legs showed clearly the dose difference between right and left legs.Absorbed doses to patient's testicles and prostrate,about 9.16 Gy,were higher than those to other organs or tissues.The skin of both legs was exposed locally to high dose radiation exposure,for which the estimated doses were in agreement with the results obtained from infrared thermal imaging.Conclusions Monte Carlo simulation technique and common software can be used for dose estimation in early stage of radiation accidents effectively with integrating proper models.