用荧光原位杂交对早先受照者剂量验证和剂量重建的探讨

介绍了近年来用荧光原位杂交技术研究早先受照的辐射生物剂量方法学和体外剂量效应关系曲线的研究，探讨了国外应用该技术对早照剂量重建和验证的研究，荧光原位杂交将为人们研究早先受照染色体损伤和剂量重建提供一个新的手段。     

多色荧光原位杂交技术的建立及其在早先受照射者剂量重建中的应用

目的 建立多色荧光原位杂交方法，并探讨用该方法进行早先辐射受照射者的剂量重建的可行性。方法 筛选8对染色体端粒和着丝粒特异性人工细菌染色体(BAC)克隆，建立多色荧光原位杂交方法，用该方法分析^60Coγ射线离体照射的新生儿脐带血淋巴细胞染色体畸变，并建立相应的标准剂量—效应曲线，参照标准剂量—效应曲线来估算两例早先受照射者的累积吸收剂量。结果 本研究中建立的多色荧光原位杂交方法用生物素和(或)地高辛将端粒和着丝粒BACDNA标记成绿、红、黄(绿 红)3种荧光染色，使得1，2，3，7，8，9，14和15号染色体很容易辨认。用该方法分析受^60Coγ射线照射的新生儿脐带血淋巴细胞染色体畸变，除断片外，其他染色体畸变的剂量—效应曲线均为线性二次剂量反应模式。用所有细胞或稳定性细胞中的完全相互易位率作指标，估算了两例早先受射照者的吸收剂量。结论 本研究所建立的多色荧光原位杂交方法可以用来进行早先受照射者的剂量重建。     

染色体畸变分析作为辐射生物剂量计的最新进展

介绍了用染色体畸变分析作为辐射生物剂量计的简史和在急性事故性照射以及早先受照中的应用。重点介绍了新近发展起来的荧光原位杂交方法对原爆幸存者，早先事故受照者和慢性职业受照者听相互易位等快速检测以及累积剂量的估算。     

染色体畸变分析作为辐射生物剂量计的最新进展

介绍了用染色体畸变分折作为辐射生物剂量计的简史和在急性事故性照射以及早先受照中的应用。重点介绍了新近发展起来的荧光原位杂交方法对原爆幸存者、早先事故受照者和慢性职业受照者中的相互易位等快速检测以及累积剂量的估算。     

染色体易位分析在回顾性生物剂量重建中的研究进展

外周血淋巴细胞染色体易位分析用于日本原爆幸存者、早先核与辐射事故受照者回顾性剂量重建已有近40年的发展史,其应用价值已得到国际学界的广泛认可。随着mFISH、dGH等分子细胞遗传学技术的发展,国际上更多关注的是受到长期慢性低剂量暴露的放射工作人员、早年参加核爆炸实验的退伍军人和医疗照射受照者等暴露人群的生物剂量的估算与...     

双色荧光原位杂交检测60Coγ射线诱发染色体畸变的剂量效应关系

目的　探索荧光原位杂交 (FISH)技术检测稳定性染色体畸变 (易位 )作为辐射生物剂量计的可行性。方法　用 1号、4号全染色体组合探针的FISH技术及常规法检测不同剂量60 Coγ射线诱发的染色体易位率和双着丝粒体率并拟合剂量效应曲线。结果　FISH技术检出的易位率、双着丝粒体率及常规法检出的双着丝粒体率与剂量间均可拟合成线性平方方程Y =c αD βD2 。FISH技术和常规法检出的双着丝粒体率差异无显著性 (P >0 0 5 )。对于 1号和 4号染色体 ,辐射诱发的易位率、双着丝粒体率的观察值与基于DNA含量的预期值相比 ,差异皆无显著性。结论荧光原位杂交技术能快速、准确地检测易位且有良好的量效关系 ,因此 ,可望成为估算慢性受照者的累积剂量和早先受照者剂量重建的理想方法     

荧光原位杂交检测上海6.25事故受照者的染色体畸变

电离辐射能诱发多种染色体畸变 ,其中染色体易位属于稳定性畸变 ,并且畸变率与最初照射剂量相关良好 ,因而易位畸变分析是回顾性剂量估计及远后效应评估的重要指标。应用染色体特异性探针进行荧光原位杂交 ,能灵敏和迅速地计数易位等稳定性畸变 ,因而非常适合于早先受照者的染色体畸变分析。本实验采用该技术研究了 6 2 5钴源事故受照者外周血淋巴细胞的染色体畸变。一、材料和方法1 材料 :5例60 Ｃｏ源事故受照者曾在照后 2 4ｈ取外周血进行染色体畸变分析估计生物剂量为 1 9～ 5 1Ｇｙ ,属急性全身均匀照射。在照后第 8、9年分别取静脉…     

《荧光原位杂交分析染色体易位估算辐射生物剂量技术方法》解读

国家职业卫生标准——《荧光原位杂交分析染色体易位估算辐射生物剂量技术方法》是在收集整理、全面阅读了与该标准有关的国内外文献资料和我国现行有效的放射性疾病诊断标准,将资料汇总分析后经实验室反复验证的基础上制定的.此标准主要用于早先事故受照人员的生物剂量估算,为临床放射损伤的诊断提供科学依据.为了使放射性疾病临床工作者更好地理解、贯彻执行该标准,该文对标准的相关内容进行了解读.     

荧光原位杂交技术与辐射生物剂量计

一种快速检测染色体畸变、特别是相互易位和微小互换的新方法——荧光原位杂交(FISH)技术,近年来在放射医学研究领域异常活跃,本文对其发展过程、探针来源、分类、特性、操作程序、影响因素以及在放射医学领域中剂量－效应关系研究、早先受照人群的剂量估算等方面都作了较为详细的描述。     

荧光原位杂交技术作为辐射生物剂量计的可行性研究

荧光原位杂交技术检测辐射诱发畸变的结果与Ｇ显带等传统方法的结果相吻合，但同时又具有其它方法所不具备的优点，特别是能准确检测易位，所以将可能成为估算慢性照射剂量和早先事故照射剂量重建的理想手段     

Comparison of X-ray dose-response curves obtained by chromosome painting using conventional and PAINT nomenclatures

Purpose: The compare the suitability of PAINT and conventional nomenclature systems for the construction of chromosome aberration dose-effect curves for X-rays using FISH techniques, and to compare these curves with those based on solid-stained dicentrics analysed in first division metaphases by the FPG technique. Materials and methods: Blood samples were irradiated at 0.1, 0.25, 0.50, 0.75, 1, 1.5, 2, 3, 4 and 5Gy 180kV X-rays. FISH painting was performed using probes for chromosomes 1, 4 and 11 in combination with a pan-centromeric probe. Results: Translocations showed a higher background frequency than dicentrics. This influences the ratio of translocations:dicentrics at the lower doses and the uncertainties of dose-effect curves for translocations. The dose-effect curves for dicentrics obtained by FISH and solid stain were in close agreement. Conclusion: For short-term biological dosimetry purposes by FISH, the use of dic (BA) (PAINT nomenclature) or total dicentrics (conventional nomenclature) should give similar dose estimates. For dose reconstruction, the use of total or complete translocations result in similar uncertainties.     

Comparison of X-ray dose-response curves obtained by chromosome painting using conventional and PAINT nomenclatures

PURPOSE: The compare the suitability of PAINT and conventional nomenclature systems for the construction of chromosome aberration dose-effect curves for X-rays using FISH techniques, and to compare these curves with those based on solid-stained dicentrics analysed in first division metaphases by the FPG technique. MATERIALS AND METHODS: Blood samples were irradiated at 0.1, 0.25, 0.50, 0.75, 1, 1.5, 2, 3, 4 and 5 Gy 180 kV X-rays. FISH painting was performed using probes for chromosomes 1, 4 and 11 in combination with a pan-centromeric probe. RESULTS: Translocations showed a higher background frequency than dicentrics. This influences the ratio of translocations:dicentrics at the lower doses and the uncertainties of dose-effect curves for translocations. The dose-effect curves for dicentrics obtained by FISH and solid stain were in close agreement. CONCLUSION: For short-term biological dosimetry purposes by FISH, the use of dic(BA) (PAINT nomenclature) or total dicentrics (conventional nomenclature) should give similar dose estimates. For dose reconstruction, the use of total or complete translocations result in similar uncertainties.     

Effect of americium-241 alpha-particles on the dose-response of chromosome aberrations in human lymphocytes analysed by fluorescence in situ hybridization

PURPOSE: To evaluate by the fluorescent in-situ hybridization (FISH) technique the dose-response and intercellular distribution of alpha-particle-induced chromosome aberrations. In particular, the validity of using the yield of characteristic types of chromosome abnormalities in stable cells as quantitative indicators for retrospective dose reconstruction has been evaluated. MATERIAL AND METHODS: Monolayers of human peripheral lymphocytes were exposed at doses from 0.02 to 1 Gy to alpha-particles emitted from a source of americium-241. The most probable energy of the alpha-particles entering the cells was 2.7 MeV. FISH painting was performed using DNA probes for chromosomes 2, 4 and 8 in combination with a pan-centromeric probe. In complete first-division cells, identified by harlequin staining, aberrations involving painted target chromosomal material were recorded as well as aberrations involving only unpainted chromosomal material. RESULTS: In total, the percentage of complex aberrations was about 35% and no dose dependence was observed. When complex-type exchanges were reduced to simple base types, the different cell distributions were clearly over-dispersed, and the linear coefficients of the dose-effect curves for translocations were significantly higher than for dicentrics. For past dose reconstruction, only a few complex aberrations were in stable cells. The linear coefficient obtained for transmissible aberrations in stable cells was more than seven times lower than that obtained in all analysed cells, i.e. including unstable cells. CONCLUSION: FISH-based analysis of complex rearrangements allows discrimination between partial-body exposures to low-linear energy transfer radiation and high-linear energy transfer exposures. In assessing past or chronic exposure to alpha-particles, the use of a dose-effect curve obtained by FISH-based translocation data, which had not excluded data determined in unstable cells, would underestimate the dose. Insertions are ineffective biomarkers because their frequency is too low.     

放射外照射事故剂量重建中的蒙特卡罗模拟方法

目的 建立放射外照射事故剂量重建的计算机系统。方法 基于MIRD的人体及其器官的数学模型，采用蒙特卡罗(MC)方法，结合 放射事故的受照模式，建立放射外照射事故剂量重建的计算机系统。结果 成功研制了放射事故剂量重建的计算机系统。用这个系统计算了河南省^60Co放射事故危重病人的剂量，其计算结果与实验模拟测量和生物剂量检测结果十分一致。结论 本系统方便、快捷，它不但可估算事故受照人员的器官剂量和全身剂量，而且也能用于事故早期剂量的估计。     

医用X射线工作者回顾性剂量估算进展

随着X射线的广泛应用,其对医用工作者的辐射致癌效应越来越受到人们关注。准确的辐射致癌危险评价应建立在完整的个人剂量信息的基础之上。然而在X射线应用的早期并没有医用X射线工作者的个人剂量信息,因此需要通过进行剂量重建来估算早期的个人剂量信息。笔者对国内外早期医用诊断X射线工作者的剂量估算的现状和进展进行了综述。     

Estimation of organ dose equivalents from residents of radiation-contaminated buildings with Rando phantom measurements.

Since August 1996, a dose reconstruction model has been conducted with thermoluminescent dosimeter (TLD)-embedded chains, belts and badges for external dose measurements on the residents in radiation-contaminated buildings. The TLD dosimeters, worn on the front of the torso, would not be adequate for dose measurement in cases when the radiation is anisotropic or the incident angles of radiation sources are not directed in the front-to-back direction. The shielding and attenuation by the body would result in the dose equivalent estimation being somewhat skewed. An organ dose estimation method with a Rando phantom under various exposure geometries is proposed. The conversion factors, obtained from the phantom study, may be applicable to organ dose estimations for residents in the contaminated buildings if the incident angles correspond to the phantom simulation results. There is a great demand for developing a mathematical model or Monte Carlo calculation to deal with complicated indoor layout geometry problems involving ionizing radiation. Further research should be directed toward conducting laboratory simulation by investigating the relationship between doses delivered from multiple radiation sources. It is also necessary to collaborate with experimental biological dosimetry, such as chromosome aberration analysis, fluorescence in situ hybridization (FISH) and retrospective ESR-dosimetry with teeth, applied to the residents, so that the organ dose equivalent estimations may be more reliable for radio-epidemiological studies.     

Twenty years of FISH-based translocation analysis for retrospective ionizing radiation biodosimetry

Purpose: The fluorescent in situ hybridization (FISH) technique, which easily detects reciprocal translocations, is currently used to estimate doses in retrospective biological dosimetry, after suspected accidental overexposure to ionizing radiation (IR). This study of 42 cases aimed to verify the appropriateness of this assay for radiation dose reconstruction, compared to the dicentric assay, and to evaluate other limitations.

Material and methods: We labeled chromosomes 2, 4, and 12 by 3-color FISH painting to detect translocations on lymphocytes of patients with suspected past IR overexposure.

Result: Translocation dose estimation showed doses significantly different from 0?Gy in 25 of the 42 cases. The lowest positive dose measured was 0.3?Gy. Several months after IR exposure, the doses measured by translocation and dicentric assays are quite similar. For a year, dose estimation by translocation assay becomes more relevant as dicentric frequency starts to decrease, coming close to 0 for more than a year after the exposure. The persistence of translocations enabled us to corroborate an overexposure 44 years earlier. Interpretation of the observed translocation yield requires the knowledge of the patient’s other radiation exposures. A dose assessment by this biomarker is relevant only if the radiation exposure is confirmed.

Conclusions: This technique is appropriate for corroborating a former IR exposure of individuals. When the radiation dose is greater than 1?Gy, the translocations in complex exchanges must be considered. Another relevant point is the use of an appropriate background yield of translocations. The dose assessment, however, also depends on exposure to various genotoxic agents besides IR. If no evidence about the existence of radiation exposure is available, dose assessment is not useful. For this reason, report only the translocation frequency and its comparison with the background yield by age class is preferable.     

Biodosimetry using chromosomal translocations measured by FISH in a population chronically exposed to low dose-rate 60 Co γ-irradiation

Purpose : To evaluate the cumulative γ-radiation personal exposure by analysing lymphocyte chromosome translocations using FISH painting and to compare FISH-derived biodoses with those derived from retrospective physical dose reconstruction in residents receiving chronic low dose-rate γ-irradiation while living in radio-contaminated buildings. Materials and methods : Chromosome translocation frequencies were evaluated by scoring 933 to 3077 metaphases under fluorescence microscope for each of the five male and four female exposed individuals after they had relocated from the radioactive environment for 34-82 months. FISH painting was conducted using kits of whole-chromosome probes for chromosomes 1, 2 and 4 in orange and 3, 5 and 6 in green and counter-stained with 4',6-diamidino-2-phenylindole (DAPI). The retrospective dose estimation termed Taiwan Cumulative Dose (TCD) was conducted by assessment using detailed information of historical exposure and the environmental radioactivity for each apartment during previous residency. Results : A total of 20 244 well-prepared metaphases were scored. Biodoses were calculated from the translocation frequencies and physical doses were estimated from detail questionnaires for each individual. The translocation frequencies measured ranged from 2.2 ×10 -3 to 26.8 ×10 -3 translocations per cell and the dose equivalent from 52.2 to 992.2mSv. A good correlation was observed between the physical and biodoses. A plot of TCD against FISH-derived doses produced D fish =0.65 D TCD, when fitted by a linear model, and D fish = 0.53 D TCD + 1.26 ×10 -4 D 2 TCD, when fitted with a linear-quadratic model. Given the scatter in the data and the extremely small quadratic dose contribution, neither model could be ruled out. Conclusion : Chromosome translocations provide a valid method of dose estimation in extremely protracted low dose-rate γ-radiation exposure. Validation of the TCD method by FISH-measured translocations supports the use of TCD for epidemiological studies.     

Biodosimetry using chromosomal translocations measured by FISH in a population chronically exposed to low dose-rate 60Co gamma-irradiation.

PURPOSE: To evaluate the cumulative gamma-radiation personal exposure by analysing lymphocyte chromosome translocations using FISH painting and to compare FISH-derived biodoses with those derived from retrospective physical dose reconstruction in residents receiving chronic low dose-rate gamma-irradiation while living in radio-contaminated buildings. MATERIALS AND METHODS: Chromosome translocation frequencies were evaluated by scoring 933 to 3077 metaphases under fluorescence microscope for each of the five male and four female exposed individuals after they had relocated from the radioactive environment for 34-82 months. FISH painting was conducted using kits of whole-chromosome probes for chromosomes 1, 2 and 4 in orange and 3, 5 and 6 in green and counter-stained with 4',6-diamidino-2-phenylindole (DAPI). The retrospective dose estimation termed Taiwan Cumulative Dose (TCD) was conducted by assessment using detailed information of historical exposure and the environmental radioactivity for each apartment during previous residency. RESULTS: A total of 20 244 well-prepared metaphases were scored. Biodoses were calculated from the translocation frequencies and physical doses were estimated from detail questionnaires for each individual. The translocation frequencies measured ranged from 2.2x10(-3) to 26.8x10(-3) translocations per cell and the dose equivalent from 52.2 to 992.2mSv. A good correlation was observed between the physical and biodoses. A plot of TCD against FISH-derived doses produced D(fish) =0.65 D(TCD), when fitted by a linear model, and D(fish) = 0.53 D(TCD)+ 1.26x10(-4 ) D(2)(TCD), when fitted with a linear-quadratic model. Given the scatter in the data and the extremely small quadratic dose contribution, neither model could be ruled out. CONCLUSION: Chromosome translocations provide a valid method of dose estimation in extremely protracted low dose-rate gamma-radiation exposure. Validation of the TCD method by FISH-measured translocations supports the use of TCD for epidemiological studies.     

用FISH技术对忻州事故宫内受照者进行回顾性剂量重建

目的 对忻州事故中宫内受照者"京"进行回顾性剂量重建.方法 受照后16年取"京"及其母亲"芳"的外周静脉血,用常规方法分析非稳定性染色体畸变,用CB法分析双核淋巴细胞微核;用全染色体探针的FISH方法分析染色体易位,参照本实验室建立的全基因组易位率与吸收剂量之间的剂量-效应曲线进行剂量估算.参照"芳"的剂量校正系数推算"京"在宫内的受照剂量.结果 受照16年后未观察到两位受照者的外周血非稳定性染色体畸变,淋巴细胞微核率在正常范围内.参照本实验室建立的吸收剂量与全基因组易位率之间的剂量-效应曲线,"芳"在16年后用FISH方法估算的剂量为0.76(0.41～1.00)Gy,而"芳"在事故后短期内估算的生物剂量为2.30(2.07～2.50)Gy,其剂量校正系数为3.03;"京"在16年后估算的剂量为0.61(0.44～0.86)Gy,推算"京"在宫内受照的剂量为1.85(1.33～2.61)Gy.结论 16年后用FISH方法对宫内受照者进行剂量重建,参照受照母亲的剂量校正系数,可推算出胎儿宫内受照的大致剂量,为临床提供依据.