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ObjectiveTo establish a dose-effect curve for semi-automatic analysis of dicentric chromosomes(DC) based on an automatic chromosome analysis system. Methods A total of three healthy volunteers were recruited as the study subjects, and their peripheral blood was collected and stimulated by X-ray at doses of 0.00, 0.10, 0.25, 0.50, 0.75, 1.00, 2.00, 3.00, 4.00, and 5.00 Gy, with the absorbed dose rate of 1.0 Gy/min. Images of DC in the mid-stage of cell division were collected using a high-throughput automatic chromosome analysis system. The DCScore software was used to automatically analyze DC aberrations, and a dose-effect curve for semi-automatic analysis of DC was fitted after manual confirmation. The fitted dose-effect curve for semi-automatic analysis of DC was validated for accuracy using three proficiency test samples from the national quality assessment of biological dose. Results The incidence of DC increased with increasing irradiation doses in the range of 0.00-5.00 Gy (P<0.01). The dose-effect curve for the fitted semi-automatic analysis of DC was ŷ =0.000 8 (±0.000 2) +0.009 2(±0.000 9) D+0.014 2(±0.000 4) D2 (R2= 0.999 8). The relative deviation between the estimated dose and the actual dose of the three test samples was about 20.00%, indicating curve applicability for biological dose estimation. Moreover, excluding the time spent on manual analysis, the semi-automatic analysis method increased the analysis efficiency by 26.0 times. Conclusion The semi-automatic analysis dose-effect curve for DC stimulated by X-ray is constructed for biological dose estimation, which can reduce the manual analysis time, and holds great potential for application in nuclear emergency response to large-scale radiation accidents.
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Objective:To improve the ability of radiation health technical institutions for biological dose estimation.Methods:A total of 144 institutions nationwide, including the CDC, prevention and treatment center for occupational disease, colleges and universities, scientific research institutes, nuclear industry systems, and medical and physical examination institutions, were organized to carry out the intercomparison of national biological dose estimation capabilities in 2022. The institutions participating in the comparison were divided into two types of A and B, through the identification of chromosome aberrations, to estimate the irradiation dose (A) or chromosome aberration rate (B). The results were summarized and compared, and the main problems were analyzed and discussed.Results:There were 60 institutions in type A, 52 qualified institutions (including 12 excellent institutions) and 8 unqualified institutions, with a pass rate of 86.7% (20.0% excellent) and a failure rate of 13.3%. There were 84 institutions participating in the biological dose estimation comparison of type B, with 48 qualified institutions, and 36 unqualified institutions, the qualified rate was 57.1%, and the unqualified rate was 42.9%.Conclusions:Most of the institutions participating in type A comparison have the ability to estimate biological dose, and more than half of the institutions participating in type B comparison have the ability to analyze chromosome aberration. The overall ability of institutions participating in type A comparison is higher than in type B.
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@#A large number of people would be exposed to irradiation in large-scale nuclear and radiation accidents or nuclear terrorist attacks. Therefore, it is urgent to establish rapid and high-throughput biodosimetry for in triage, providing a basis for emergency management. Imaging flow cytometry (IFC) possesses the high through put advantages of traditional flow cytometry and the sensitivity and specificity of microscope, and has a good application prospect in the research and development of rapid, automated, and high-throughput biological dose estimation technology. This article reviews the application progress of IFC in biodosimetry, and provides a reference for the development of biological dose estimation and detection equipment for large-scale nuclear and radiation accidents.
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Objective:To assess proton biological dose with using two kinds of relative biological effect models and to compare them with traditional clinical proton biological dose ( Dose1.1). Methods:Based on Particle simulation tools(TOPAS), physical dose, LET d and LET t were calculated in water phantom and two anthropomorphic phantoms (brain and prostate tumors) respectively. Then DoseLET d and DoseLET t were calculated according to different relative biological effect models, an RBE was 1.1 in traditional clinical proton biological dose calculation. Three kinds of biological doses were compared in the water phantom. To quantify the differences between three method in anthropomorphic phantoms, three points ( D1, D2, D3) were selected according to the physical dose to compare the biological dose. Results:DoseLET d and DoseLET t in water phantom showed the same trend with water depth and both of them were higher than Dose1.1 at the end of proton beam range. The maximal difference between DoseLET d and DoseLET t in the anthropomorphic phantoms was 10.08 cGy, where the relative difference was less than 5%. When DoseLET d and DoseLET t were compared with Dose1.1, the maximal differences in brain tumor target were 71.97 cGy and 61.91 cGy respectively, where the relative differences were less than 25%. The maximal differences in prostate tumor target were 25.95 and 19.96 cGy respectively, where the relative differences were less than 12%. However, the differences outside the target were very small, where the maximal differences in brain and prostate tumors were 5.99 cGy and 9.92 cGy respectively, and the relative differences were less than 5%. Conclusions:Biological doses calculated by two method are of little difference in both water and anthropomorphic phantoms, however, large differences were observed when they were compared with the traditional clinical proton biological dose especially in the high dose area.
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Objective:To evaluate biological dose and retrospective biodosimetry of a case of large area back skin injury caused by suspected interventional procedure.Methods:Peripheral blood from the patient was collected at about 7 months after interventional procedure, and the chromosomal aberrations in peripheral blood cells were analyzed to evaluate the retrospective biodosimetry using the correction factor of dose estimation, Dolphin′s model and Qdr method, respectively. Results:Based on the amounts of semi-automated dic and manually detected dic plus ring, the whole-body average absorbed dose of the victim was estimated to be 0.68-0.95 Gy by four different dose response curves. Over dispersion of dic or dic plus ring was also detected, and the efficiency of dose assessment was obviously increased using dic semi-automatic detection. Based on three different retrospective biodosimetry models, the estimated average absorbed dose was further corrected to be between 1.80-2.86 Gy, which was consistent with clinical diagnosis of degree Ⅳ radiation skin injury.Conclusions:A case of suspected radiation skin injury was confirmed by chromosomal aberration analysis and it’s biodosimetry was reconstructed, suggesting that the unstable chromosomal aberration analysis may be applicable to assess the retrospective biodosimetry of non-uniform local radiation exposure.
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Objective To analyze the biological dose estimation ability of the radiation health technology institutions nationwide from 2015 to 2017,and their development in recent years.Methods SPSS 19.0 software was used to analyze and pack the data involved in the 2015-2017 year assessments by using x2 test.Statistical analysis was conducted of qualification rate,excellent rate,participating units and dose estimation deviation distribution.Results The qualification rate gradually increased from 2015 to 2017.Compared with 2015,the passing rate significantly increased in 2017 with statistically significant difference(x2 =3.978,P ＜0.05).A total of 53 units participated in the biological dose assessment,of which 30 units were involved over the three consecutive years,accounting for 57％.In the distribution of the relative deviation of dose estimates made by the units participating in the three-year assessment,the proportion of estimated deviations in the range of 5％-10％ increased whereas those in the range of 15％-20％ and ＞ 20％ decreased.Conclusions During 2015-2017 year period the biological dose estimation ability of all units involved in the assessment nationwide was basically stable,with gradually improved test level,qualification rate and steady excellence rate.
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OBJECTIVE: To estimate the biological dose by the chromosome aberration analysis in a victim suffered in the radioactive source-loss accident in Nanjing City. METHODS: Peripheral blood sample of the victim was collected 6 days after radioactive exposure. Individual radioactive biological dose was estimated by identifying the aberration of the dicentrics plus centric rings in the metaphase chromosome of cells. The distribution of chromosome aberration was tested by the Poisson distribution. Impure Poisson distribution was used to estimate the radiation dose. RESULTS: Among the 353 cells observed at metaphase,75 aberration of dicentrics plus centric rings were found,43 cells had 1 aberration and 7 cells had 2 aberrations. Moreover,there were 3 multi-aberration cells with 3,4 and 11 aberrations respectively. The average individual radiation dose was estimated to be 1. 52 Gy,which was consistent with the clinical diagnosis as mild acute bone marrow radiation disease. The Poisson distribution u test revealed that the patient suffered from nonhomogeneous radiation.By the impure Poisson distribution test,the radiation exposure proportion of the whole body was estimated to be 55% and the average dose was 3. 02 Gy. CONCLUSION: The biological dose estimation was successfully performed,the results showed that this was a case of nonhomogeneous irradiation.
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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.
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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.
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Objective On basis of physical dose optimization, LQ model was used to investigate the difference between the curves of biological effective dose and physical isodose. The influence of applying the biological dose concept on three dimensional conformal radiotherapy of prostate carcinoma was discussed. Methods Four treatment plannings were designed for physical dose optimization: three fields, four-box fields, five fields and six fields. Target dose uniformity and protection of the critical tissue -rectum were used as the principal standard for designing the treatment planning. Biological effective dose (BED) was calculated by LQ model. The difference between the BED curve drawn in the central layer and the physical isodose curve was studied. The difference between the adjusted physical dose (APD) and the physical dose was also studied. Results Five field planning was the best in target dose uniformity and protection of the critical tissue -rectum. The physical dose was uniform in the target, but the biological effective doses revealed great discrepancy in the biological model. Adjusted physical dose distribution also displayed larger discrepancy than the physical dose unadjusted. Conclusions Intensified Modulated Radiotherapy (IMRT) technique with inversion planning using biological dose concept may be much more advantageous to reach a high tumor control probability and low normal tissue complication probability.
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Objective A biological dose estimation by cytokinesis-block micronucleus(CBMN)assay was performed on 2 patients exposed to accidental radiation.Method Micronucleus assay and dose estimation by CBMN in peripheral blood and bone marrow were performed in 2 patients(A and B)suffering from radiation sickness.Results No binucleated lymphocytes were observed in peripheral blood of 2 patients.The results of bone marrow examination showed that only one binucleated cell was discovered in patient A.The rough estimation of radiation dose of A was above 20Gy according to the degree of reduction of binucleated cell in our previous study.The micronucleus frequency was 2.42 per cell and the dose estimation was 8.7(8.0-9.4)Gy for patient B.These results were approximately in accordance with that of dose estimations by physical method,chromosome aberration analysis,ESR method,and clinical manifestations.Conclusion MN assay is simple,quick and accurate.It is a reliable biodosimetry in addition to chromosome aberration analysis.