我国人群辐射致胃癌危险系数估算研究

目的 估算我国人群胃癌辐射致癌危险系数.方法 应用美国电离辐射效应委员会研发的日本原子弹爆炸幸存者胃癌辐射致癌危险模型,估算其辐射致癌超额相对危险和绝对危险系数.综合日本人群辐射致癌危险转移为美国人群危险的多种转移方法,确定由日本人群向我国人群危险转移模型为相乘相加混合模型(算数尺度下,相乘和相加模型权重分别为0.7和0.3).根据我国肿瘤登记年报胃癌基线发病率,利用曲线拟合方法,估算其性别-年龄别基线发病率.综合日本人群胃癌辐射致癌危险系数及我国人群胃癌基线发病率,结合适用于我国人群的危险转移方法,估算我国人群胃癌辐射致癌危险系数.结果 估算获得我国人群胃癌辐射致癌超额相对危险系数值,男性为0.26/Sv,女性为0.64/Sv(30岁受照,60岁患癌).受照年龄越小,患癌年龄越小此系数越大.结论 我国人群胃癌辐射致癌危险系数高于日本原子弹爆炸幸存者,二者随性别-年龄变化趋势相同.     

辐射流行病学研究中的统计分析方法(二): 危险和辐射致癌危险概率的计算

辐射流行病学研究中的统计分析方法（二）：危险和辐射致癌危险概率的计算李伟林作者单位：２５０００７苏州，苏州医学院放射医学系１队列研究１．１不分层资料：这种研究资料可列成表１形式。表１队列研究（不分层）资料危险计算表项目暴露组对照组合计随防期间病例数ｍ...     

辐射致白血病危险从日本人群向中国人群的转移探讨

目的 通过日本原爆人群的辐射致白血病危险估算中国人群白血病的超额相对危险(ERR)值,探讨合适的人群危险转移方法.方法 危险计算使用BEIR Ⅶ 辐射致癌计算模型及人群危险转移模型,中国人群率采用《2012中国肿瘤登记年报》中2009年中国肿瘤基线发病率.通过不同国家人群率的比较,来调整权重系数.结果 得到经人群转移后的中国人群白血病ERR值;对中国人群男性拟定相加模型权重系数为0.2、相乘模型为0.8,对女性相加模型权重系数为0.15、相乘模型为0.85.结论 在辐射致白血病危险人群转移中从总体考虑调整权重系数,得到适于估算中国人群辐射致白血病危险的人群ERR值.应用新的中国人群发病率将辐射致白血病危险直接从日本人群转移到中国人群,得出适于中国人群的辐射致白血病危险的转移方法.     

日本癌症发病率的新资料

设在日本广岛和长崎的辐射效应研究所(RERF)对原子弹爆炸幸存者进行了40多年的随访调查,此项研究计划包括寿命调查(LSS)、病理学研究、成年人健康调查(AHS)、宫内受照和遗传学研究。     

生物剂量学技术在放射流行病学中的应用

低剂量电离辐射致癌危害的流行病学研究遇到了很大的困难，以研究电离辐射与生物效应定量关系主核心的放射生物剂量学与相关技术可望对流行病的剂量重建，辐射致癌危险估算，生物学模型建立和危险预测有人群中癌易感性和辐射致癌敏感性检测等提供帮助，两者的结合将把放射流行病学推向分子放射流行病学的新阶段。     

辐射致癌危险预测模型的改进

对辐射致癌危险度的计算,是基于特定肿瘤的危险预测模型。最近,对原有模型中使用的一些参数进行了改进,包括采用两种危险系数即死亡率危险系数和发病率危险系数、提出年龄和性别特异性的致癌危险系数等。应用这些改进的危险系数,计算并给出了不同核素和不同暴露方式下组织和器官的辐射致癌危险度估计值。     

辐射致癌危险预测模型的改进

对辐射致癌危险度的计算，足基于特定肿瘤的危险预测模型。最近，对原有模型中使用的一些参数进行了改进，包括采用两种危险系数即死亡率危险系数和发病率危险系数、提出年龄和性别特异性的致癌危险系数等，应用这些改进的危险系数，计算并给出了不同核素和不同暴露方式下组织和器官的辐射致癌危险度估计值。     

辐射致癌病因概率的计算方法及其应用的进展

辐射致癌病因概率（ＰＣ）是致癌病因中归因于辐射的份额,得自辐射引起某种癌症的超额相对危险与全部相对危险的比值ＥＲＲ／（１＋ＥＲＲ）。ＰＣ概念的出现是为了解决辐射致癌的职业赔偿,为此１９８５年美国国立卫生研究院（ＮＩＨ）编制了计算ＰＣ的放射流行病学表,...     

照射和骨髓治疗活存小鼠中白内障的发生率

哺乳动物眼晶体发生白内障,是电离辐射的重要后期效应之一。人发生放射性白内障的资料来自日本原子弹爆炸幸存者、辐射事故伤员、放疗病人和辐射工作者;根据前两类人员受到一次全身不均匀丙、中射线照射后的观察,发生放射性白内障的潜伏期皆为数年以上。二次大战以后,很多国家都很重视急性     

辐射致癌病因概率计算方法研究进展

为解决辐射致癌患者的赔偿问题,美国国立卫生研究院提出用病因概率（probability of causation,PC）来评估癌症和所受电离辐射之间的关联程度,我国也发布了根据PC判断放射性肿瘤的相关国家标准。本文总结了与PC计算相关的辐射致癌超额危险模型的研究进展,并介绍了超额危险在不同人群之间的转换方法、与低剂量和低剂量率的依赖关系、其他流行病学危险因子的修正方法以及PC的应用情况。     

Absence of evidence for differences in the dose-response for cancer and non-cancer endpoints by acute injury status in the Japanese atomic-bomb survivors

Purposes : To ascertain possible evidence for radiosensitive subgroups in the Japanese atomic-bomb survivors. Materials and methods : Time- and age-adjusted relative risk models were fitted to the Japanese atomic-bomb survivor mortality data, taking account of the modifying effects of acute injury status and adjusting for random dosimetric errors. Results : For leukaemia, there were statistically significantly higher relative risks among those persons reporting either epilation (two-sided p =0.03) or burns (two-sided p =0.02), but after adjustment is made for the effects of dosimetric error these results become statistically non-significant (two-sided p >0.05) For all other endpoints (cancers other than leukaemia, benign neoplasms, cardiovascular disease, non-cancer and non-cardiovascular disease) there were no statistically significant modifying effects on relative risk of acute injury status, whether or not adjustment is made for the effects of dosimetric error. Conclusions : Apart from leukaemia, there are generally no indications for cancer or other disease endpoints of variations in dose-response by acute injury status. The increased risks observed for leukaemia among those reporting epilation or burns are much diminished after adjustment for dosimetric error, and so there is no strong evidence of a sensitive subgroup within the Life Span Study cohort.     

Absence of evidence for differences in the dose-response for cancer and non-cancer endpoints by acute injury status in the Japanese atomic-bomb survivors

PURPOSES: To ascertain possible evidence for radiosensitive subgroups in the Japanese atomic-bomb survivors. MATERIALS AND METHODS: Time- and age-adjusted relative risk models were fitted to the Japanese atomic-bomb survivor mortality data, taking account of the modifying effects of acute injury status and adjusting for random dosimetric errors. RESULTS: For leukaemia, there were statistically significantly higher relative risks among those persons reporting either epilation (two-sided p=0.03) or burns (two-sided p=0.02), but after adjustment is made for the effects of dosimetric error these results become statistically non-significant (two-sided p>0.05) For all other endpoints (cancers other than leukaemia, benign neoplasms, cardiovascular disease, non-cancer and non-cardiovascular disease) there were no statistically significant modifying effects on relative risk of acute injury status, whether or not adjustment is made for the effects of dosimetric error. CONCLUSIONS: Apart from leukaemia, there are generally no indications for cancer or other disease endpoints of variations in dose-response by acute injury status. The increased risks observed for leukaemia among those reporting epilation or burns are much diminished after adjustment for dosimetric error, and so there is no strong evidence of a sensitive subgroup within the Life Span Study cohort.     

Comparing second cancer risk for multiple radiotherapy modalities in survivors of hodgkin lymphoma

Objectives:To assess if excess absolute risk (EAR) of radiation-induced solid cancer can be used to rank radiotherapy plans for treatment of Hodgkin lymphoma (HL) in a statistically significant way.Methods:EAR models, calibrated with data from the Life Span Study and HL survivors, have been incorporated into a voxelised risk-calculation software, which is used to compare four treatment modalities planned for five virtual HL patients. Organ-specific parameters are generated repeatedly in a Monte Carlo fashion to model their uncertainties. This in turn enables a quantitative estimation of the EAR uncertainties.Results:Parameter-driven uncertainties on total EAR are around 13%, decreasing to around 2–5% for relative EAR comparisons. Total EAR estimations indicate that intensity modulated proton therapy decreases the average risk by 40% compared to the intensity modulated radiation therapy plan, 28% compared to the volumetric modulated arc therapy plan whereas the three-dimensional conformal radiation therapy plan is equivalent within the uncertainty.Conclusion:Relative EAR is a useful metric for distinguishing between radiotherapy plans in terms of second cancer risk.Advances in knowledge:Relative EAR is not dominated by model or parameter uncertainties and can be used to guide the choice of radiotherapy for HL patients.     

A-bomb survivors: reassessment of the radiation hazard

Newly released data from the Radiation Effects Research Foundation on the survivors of the Hiroshima and Nagasaki A-bombing allow a reassessment of radiation hazards. It appears that deaths from marrow damage (such as aplastic anaemia) continued after 1950. The Life Span Study cohort appears biased in favour of persons with high immunological competence, the result of infants and the elderly being more likely to die before 1950 than young adults. A study of survivors of in utero exposures suggests that embryos are more sensitive to the lethal effects of radiation than more mature foetuses. Current estimates of cancer risks from radiation may only apply to young adults with high immunological competence; young children and the elderly may be at greater risk.     

Towards a common global ethic: a rational approach to terrorism

Newly released data from the Radiation Effects Research Foundation on the survivors of the Hiroshima and Nagasaki A‐bombing allow a reassessment of radiation hazards. It appears that deaths from marrow damage (such as aplastic anaemia) continued after 1950. The Life Span Study cohort appears biased in favour of persons with high immunological competence, the result of infants and the elderly being more likely to die before 1950 than young adults. A study of survivors of in utero exposures suggests that embryos are more sensitive to the lethal effects of radiation than more mature foetuses. Current estimates of cancer risks from radiation may only apply to young adults with high immunological competence; young children and the elderly may be at greater risk.     

Dose-response models and methods of risk prediction and causation estimation

Dose-response models are mathematical expressions that describe the relationship between absorbed dose and radiogenic effects. The limited quality and quantity of human dose-response data make it necessary to use fairly simplistic models. Most current low-LET data support the linear-quadratic model in which radiogenic effects are linearly dependent at low doses and then become quadratically curved at higher doses. Some types of effects never exhibit a quadratic component, remaining linear over a wide range of absorbed dose. Future progress in developing more refined dose-response models is more likely to come from a better understanding of the fundamentals of radiation carcinogenesis rather than better data or better curve-fitting techniques. The risk of radiation injury is a prospective estimation of the probability that some harm will result in the future as a consequence of having been irradiated. Quantitative risk estimates for the carcinogenic, genetic, and fetal effects of low level radiation that have been determined by national and international organizations are of the order of magnitude of one chance fatality in 10,000/rem. Causation estimation is the retrospective analysis of the probability that cancer observed in an irradiated individual was caused by radiation as opposed to some other agent. Depending on the dose type of cancer, gender, age at time of irradiation, and time since irradiation, the probability of causation can range from 0% to 100%. Methods for calculation of the probability of causation for certain types of cancer and irradiation circumstances have been developed recently by the National Institutes of Health.     

Comparisons of lung tumour mortality risk in the Japanese A-bomb survivors and in the Colorado Plateau uranium miners: support for the ICRP lung model

PURPOSES: To estimate the ratio of risks for exposure to radon progeny relative to low-LET radiation based on human lung cancer data, taking account of possible time and age variations in radiation-induced lung cancer risk. MATERIALS AND METHODS: Fitting two sorts of time- and age-adjusted relative risk models to a case-control dataset nested within the Colorado Plateau uranium miner cohort and to the Japanese atomic (A)-bomb survivor mortality data. RESULTS: If all A-bomb survivors are compared with the Colorado data, there are statistically significant (two-sided p < 0.05) differences between the two datasets in the pattern of the variation of relative risk with time after exposure, age at exposure and attained age. The excess relative risk decreases much faster with time, age at exposure and attained age in the Colorado uranium miners than in the Japanese A-bomb survivors. If only male A-bomb survivors are compared with the Colorado data, there are no longer statistically significant differences between the two datasets in the pattern of variation of relative risk with time after exposure, age at exposure or attained age. There are no statistically significant differences between the male and female A-bomb survivors in the speed of reduction of relative risk with time after exposure, age at exposure or attained age, although there are indications of rather faster reduction of relative risk with time and age among male survivors than among female survivors. The implicit risk conversion factor for exposure to radon progeny relative to the A-bomb radiation in the male survivors is 1.8 x 10(-2) Sv WLM(-1) (95% CI 6.1 x10(-3), 1.1 x 10(-1)) using a model with exponential adjustments for the effects of radiation for time since exposure and age at exposure, and 1.9 x 10(-2) Sv WLM(-1) (95% CI 6.2 x 10(-3), 1.6 x 10(-1)) using a model with adjustments for the effects of radiation proportional to powers of time since exposure and attained age. Estimates of the risk conversion factor calculated using variant assumptions as to the definition of lung cancer in the Colorado data, or by excluding miners for whom exposure estimates may be less reliable, are very similar. The absence of information on cigarette smoking in the Japanese A-bomb survivors, and the possibility that this may confound the time trends in radiation-induced lung cancer risk in that cohort, imply that these findings should be interpreted with caution. CONCLUSIONS: There are no statistically significant differences between the male A-bomb survivors data and the Colorado miner data in the pattern of variation of relative risk with time after exposure and age at exposure. The risk conversion factor is very close to the value suggested by the latest ICRP lung model, albeit with substantial uncertainties.