飞行人员2007年宇宙辐射受照水平的估算分析

[目的]根据国际放射防护委员会（ICRP）和我国国家标准中关于飞行人员宇宙辐射防护的要求,估算某航空公司飞行人员2007年飞行中受到的宇宙辐射受照水平。[方法]根据2007年航空公司各航班的飞行数据,用中国民航总局组织开发的民航飞行宇宙辐射有效剂量计算系统（CARD）计算各航班的年均宇宙辐射有效剂量及年均剂量率,估算飞行人员的辐射受照水平;用美国联邦航空局（FAA）的CARI-6软件计算部分航线飞行人员宇宙辐射受照水平,并对上述两种计算方法的结果进行比较。[结果]2007年460个航班中,单程飞行1次受到宇宙辐射有效剂量最大为17.10μSv,最小为0.36μSv,平均为3.78μSv。全公司飞行员年均受照有效剂量最大为1.81mSv/a,最小为0.72mSv/a,平均为1.45mSv/a;乘务员最大为2.54mSv/a,最小为1.45mSv/a,平均为1.81mSv/a。[结论]飞行人员受到的宇宙辐射有效剂量均在ICRP和我国国家标准建议的限值以下。     

1例疑似放射性职业病患者受照剂量的估算

为确认1例疑似放射性职业病患者受照剂量,按照《外照射慢性放射病剂量估算规范》要求进行受照剂量估算。结果显示,有效剂量约为1.64Sv,眼晶体吸收剂量约为3.92Gy,皮肤吸收剂量约为19.01Gy。提示,放射工作人员应提高自身防护意识,减少受照剂量。     

2例低剂量率放射事故受照者生物剂量估算

目的观察某次钴源丢失事故中受照人员健康损害情况。方法应用常规染色体畸变分析技术,利用本实验室建立的低剂量率离体照射人外周血染色体畸变的剂量—效应曲线进行生物剂量估算。结果2名事故受照人员的“双着丝粒体 着丝粒环”(d ic r)畸变频率明显高于自发频率,其中1人为均匀照射,另1人为不均匀照射,根据“d ic r”估算的受照人员生物剂量分别为0.53 Gy和1.09 Gy。结论本次事故中,2名受照人员已观察到明显的染色体损伤。     

2例~(192)Ir辐射事故受照人员的剂量估算和医学处理

目的通过对一起192Ir辐射事故中2例外照射受照人员的剂量估算、医学处理的分析,为核与辐射事故医学应急救治提供资料和经验。方法采用热释光剂量计法估算物理剂量;染色体畸变、CB微核分析及HPRT基因位点突变频率分析法估算生物剂量;观察受照者的临床表现、免疫功能、精液常规、眼晶体、心理等变化。结果物理剂量估算,"陈"的全身平均吸收剂量为2.85 m Gy~88.50 m Gy、"宋"的全身平均吸收剂量为2.85 m Gy~64.05 m Gy;事故后2例受照者均有神经衰弱症状,"陈"CD8+细胞比率升高,"宋"NK细胞比率下降、精子活率和活力出现异常。"陈"发生急性放射性皮肤损伤Ⅱ度。心理测评显示,2例受照者均出现焦虑、抑郁。结论系统地对2例192Ir受照者进行了剂量估算、医学处理,为类似病例的处置提供借鉴。     

2003-2007年广东省放射工作人员受照剂量水平与分析

目的 对2003-2007年广东省放射工作人员个人剂量监测资料进行总结分析。方法 采用热释光剂量测量法。结果 5年共监测20 997人次,受照剂量超过5 mSv的人员占2.0%,只有1人受照剂量超过20 mSv,人均年剂量当量0.66 mSv,实测集体剂量当量13.85人·Sv。核工业人均年剂量当量最大,为1.80mSv,其次是核医学和工业探伤,分别为0.58和0.45 mSv,其他工种受照剂量都较小;核工业对集体剂量的贡献最大,达9.14人·Sv,占66.0%,其次是X射线诊断,为2.18人·mSv,占15.7%。结论 广东省放射工作人员人均受照剂量基本呈逐年下降,同时低于全国平均水平。     

鹤壁60Co源放射事故受照者的生物剂量估算

目的估算一例河南鹤壁60Co源放射事故受照者的生物剂量。方法利用临床应急生物剂量指标进行初步估算。受照后33d取血培养，进行淋巴细胞染色体畸变分析，以第一次有丝分裂细胞双着丝粒体加着丝粒环(“双 环”)畸变频率作为进一步生物剂量估算依据。用“双 环”畸变在细胞间的泊松分布情况，检验照射的均匀性。结果根据临床表现粗略估算全身等效剂量为1～2Gy，右手局部皮肤剂量≥20Gy。依据“双 环”畸变频率估算全身等效剂量为1．54Gy，95％可信限下限值为1．32Gy，上限值为1．75Gy。检验证实“双 环”畸变在细胞间的分布大体符合泊松分布。结论综合判断患者受到比较均匀的照射，确诊为轻度骨髓型急性放射病伴急性放射性右手皮肤损伤Ⅳ。。     

2例严重的~(60)Co放射事故受照人员的牙齿剂量估算

目的用电子自旋共振方法对山东事故中两例受照人员的3颗牙齿进行剂量估算。方法将受照人员的牙齿经过处理后得到牙釉质样品,进行ESR信号测量,将样品ESR信号的相对强度代入本实验室建立的牙釉质剂量响应曲线后,得到的3颗牙齿的吸收剂量。结果两例受照人员牙釉质ESR吸收剂量剂量分别为:受照人A的牙齿剂量为26.1~29.4Gy;受照人B的两颗牙齿剂量分别为14.9~18.3Gy,15.2~18.5Gy。结论两例受照人员牙釉质ESR剂量测量方法为大剂量照射事故剂量估算提供了一种重要的依据。     

131I放射性药物生产工作人员剂量估算与评价

目的 理论估算¹³¹I放射性药物生产过程中放射工作人员的外照射和内照射剂量,与现场辐射监测结果比较,探讨放射工作人员年受照剂量估算与评价方法。方法 以某一¹³¹I放射性药物生产企业为例,通过估算工作人员在分装、转移、包装以及转运四个环节工作人员全身和手部剂量率以及工作人员操作过程中对¹³¹I核素的摄入量,全面分析工作人员外照射和内照射剂量。结果 理论估算外照射最大受照剂量为3.23 mSv/a;实测推算工作人员外照射最大受照剂量为1.72 mSv/a,理论估算结果比监测结果保守;工作人员手部外照射受照剂量偏高112.3 mSv/a,约占年剂量限值的1/5;内照射剂量为0.23 mSv/a,占总受照剂量7.1%。结论 放射性药物生产¹³¹I项目对工作人员辐射影响分析时,工作人员手部受照剂量偏高,应采取必要的辐射防护措施,加强防护和管理;其次工作人员内照射剂量不容忽视,应设计合理的气流组织,定期对气溶胶进行有效监测。     

大亚湾核电站维修人员职业外照射监测结果与分析

目的 了解大亚湾核电站2003~2005年维修工作人员的职业性外照射剂量。方法 热释光剂量测量方法。结果 三年的实测集体剂量当量是6.13人·Sv,平均年剂量当量是1.86mSv。2003~2005年的人均年剂量当量分别是1.99、1.97和1.64mSv,实测集体剂量当量分别是2.40、1.73和2.00人·Sv。在各工种中,现场通用技术服务人员的人均年剂量当量最大,为2.28mSv,对实测集体剂量当量的贡献也最大,为5.74人·Sv,占实测集体剂量当量93.6%,其它工种的人均年剂量当量及对实测集体剂量当量的贡献都较小。三年里超过国家标准年剂量限值有一人,为33.60mSv。结论 核电站维修工作人员的受照剂量比其他工种放射工作人员的受照剂量高。     

某汽车能源有限公司85Kr测厚仪放射防护评价分析

采用现场调查和检测检验法，对某汽车能源有限公司车载动力电池项目85Kr测厚仪工作场所放射剂量水平及防护措施进行评价。结果显示，源容器表面5 cm处周围的辐射水平为0.48~7.26 μSv/h，剂量当量率控制值＜25 μSv/h；源容器表面100 cm处周围的辐射水平为0.14~2.32 μSv/h，剂量当量率控制值＜2.5 μSv/h。放射工作人员年受照剂量估算为0.029 mSv。该公司在确保现有放射防护管理措施的情况下，可有效预防和控制辐射事故的发生。     

241Am-Be中子源测井的辐射剂量估算与防护措施探讨

目的 调查研究²⁴¹Am-Be中子源测井过程中操作人员所受辐射剂量,探讨测井中子源的管理及防护对策。方法 通过对某公司操作现场观摩和现场测量,获取中子源表面γ剂量率、中子剂量率以及取源、运输、装源等过程的操作时间和距离等参数,计算²⁴¹Am-Be中子源测井过程中操作人员所受到的辐射剂量,分析操作人员所受个人有效剂量的来源和占比。结果 一次源罐检查、搬运和检测过程中的中子照射和γ射线照射的有效剂量分别为94.17μSv和2.72μSv,一次装源和取源的中子照射和γ射线照射的有效剂量分别为36.66μSv和24.08μSv,中子源一次测井全过程的中子照射和γ射线照射的有效剂量分别为130.83μSv和26.80μSv;按每年测井100次估算,则中子源测井总的年有效剂量为15.78 mSv。结论 某公司²⁴¹Am-Be中子源测井过程中操作人员所受剂量主要为中子照射剂量,需要加强中子源管理和采取有效的中子辐射安全管理与防护措施。     

The third analysis of cancer mortality among Japanese nuclear workers, 1991-2002: estimation of excess relative risk per radiation dose

The present study estimated excess relative risk per sievert (ERR/Sv) of cancer mortality among the cohort of 200?583 male Japanese nuclear workers, with an average individual cumulative dose of 12.2 mSv (<10 mSv, 75.4%; 100 + mSv, 2.6%), conducting Poisson regression using dose category specific observed and expected numbers of deaths, and average doses obtained from the official report of the Radiation Effects Association (REA) on the analysis of mortality of Japanese nuclear industry workers for 1991-2002, which reported the estimates of ERR/Sv for leukaemia but not for all cancers or any other cancer site. The possible confounding biases from drinking alcohol and smoking tobacco were evaluated by examining the association of cumulative radiation dose with the mortality of cancers related to drinking or smoking. For leukaemia (80 deaths), the estimate of ERR/Sv was - 1.93 (95% confidence interval (CI) = - 6.12, 8.57). For all cancers excluding leukaemia (2636 deaths), while the ERR/Sv was estimated to be 1.26 (95%CI = - 0.27, 3.00), confounding by alcohol consumption was suspected since the ERR/Sv estimate of alcohol-related cancers was 4.64 (95%CI = 1.13, 8.91) and the ERR/Sv estimate of all cancers excluding leukaemia and alcohol-related cancers was 0.20 (95%CI = - 1.42, 2.09). In conclusion, confounding by important lifestyle factors related to cancer risk may have a substantial effect on risk estimates, especially when conducting studies of low cumulative dose and, accordingly, low statistical power. Pooled analysis or meta-analysis of nuclear workers for solid cancers needs to take this point into account.     

Occupational doses from radon in Spanish spas

Recent international recommendations have included exposure to natural radiation as one of the sources to monitor in certain occupationally exposed groups. Among those mentioned are workers in thermal spas, who may be exposed to high radiation doses due to the high concentration of radon in the indoor air of the spa. This paper presents the methodology and the results of an evaluation of radiation doses to the staff in different thermal spas in Spain. Different series of samples were collected and measurements made for the radon concentrations in water in 54 spas and in air in 20 spas. In six of the latter group, the air radon concentration was studied in different working areas occupied by the employees. The radon concentrations in water were between <2 and 775 x 10(3) Bq m(-3). The radon concentrations in air were between <10 and 5,200 Bq m(-3). The latter were used to estimate the dose received by each occupational group in the spa by taking into account the radon concentration in their main working area. By means of an exposure-dose conversion factor of 1.43 Sv per J h m(-3), the estimated effective doses were found to lie between 1 and 44 mSv y(-1). This upper limit is higher than the recommended annual limit of 20 mSv y(-1) for an occupational dose.     

An overexposure in industrial radiography using an 192Ir radionuclide

An industrial radiographer was accidentally exposed to a high dose of ionizing radiation from an 192Ir source during radiography of weldjoints in gas pipelines. Some symptoms of high radiation exposure occurred immediately after the incident. The clinical effect of skin erythema developed within 7 d, leading to progressive tissue deterioration. The dose to the body was estimated to be about 2-3 Gy, and the dose to the fingertips was approximately 24 Gy.     

最近一个太阳活动周期内飞行人员宇宙辐射水平的评估

目的 计算最近一个太阳活动周期内(1997 - 2007年)飞行人员每年的宇宙辐射受照水平,为制定飞行人员的辐射防护管理措施提供依据.方法 根据460条飞行航线数据,用民航宇宙辐射剂量计算系统CARD计算飞行人员飞行过程中受到的宇宙辐射有效剂量.结果 最近一个太阳活动周期内,在460条航线中,一次飞行过程中受宇宙辐射有...     

Analysis of potential radiobiological effects related to a unified skin dose limit

A unified skin dose limit of 0.5 Sv at a depth of 70 microm averaged over the highest 10 cm2 of skin exposed was evaluated to replace the existing limit of 0.5 Sv averaged over 1 cm2. This limit would apply to all exposures including non-uniform exposures such as from hot particles on or off skin, skin contamination, or beams of charged particles or photons. The probabilities and severity of both stochastic and deterministic risks were estimated for a wide range of worst-case exposure scenarios using published radiobiological data and calculations of radial- and depth-dose distributions. Results indicate that exposures at the unified dose limit have the potential to cause effective doses of about 17 microSv (1.7 mrem), estimated stochastic risks of <3.3 x 10(-7) fatal skin cancers, and <1.6 x 10(-4) non-fatal skin cancers. The worst deterministic effects were estimated to be (a) based on a 2 Gy threshold, transient erythema induction to an area of 2.5 cm2 for uniform skin contamination over this same area and 0.65 cm2 for a 60Co hot particle 3 mm off of skin, (b) based on data for pig skin, 50% probability that 0.5 cm2 of skin would suffer 20% dermal thinning for uniform contamination with 106Rh spread over the same area, and (c) 10% probability of barely detectable transient acute necrosis or ulceration for 60Co or activated fuel particles 0.4 mm off of skin. It was concluded that the unified limit would provide a more logical system of dose control with possible savings of whole-body dose and other benefits.     

南宁市地铁1号线各站段氡浓度水平以及地表γ剂量率水平研究

目的 掌握南宁市地铁1号线车站内氡浓度水平以及γ射线辐射水平,评价其对地铁工作人员造成的辐射剂量。方法 采用闪烁瓶法和瞬时监测相结合的方法,对南宁市地铁1号线氡浓度水平和γ射线瞬时剂量率进行监测,并对数据进行分析和比较,根据联合国原子辐射效应科学委员会推荐的评价方法估算地铁工作人员受到氡及其衰变子体以及γ辐射水平造成的人均年有效照射剂量,评价其卫生学效应。结果 南宁市地铁1号线全线氡浓度水平均值为18.5 Bq/m³,地铁氡及其子体给工作人员造成的人均年有效剂量为0.133 mSv/a,地铁站地表γ射线辐射水平均值为0.097 μSv/h,所造成的地铁工作人员年有效剂量0.194 mSv/a,二者造成的总剂量为0.327 mSv/a。结论 南宁市地铁1号线氡浓度水平和γ射线瞬时剂量率不会对地铁工作人员和乘客造成额外明显的受照负担。     

A retrospective evaluation of radiation dose associated with low dose FDG protocols in whole-body PET/CT

The objective of the study is to retrospectively measure patient radiation dose resulting from whole body X-ray CT and FDG PET studies using a low-dose protocol performed on the Siemens Biograph mCT scanner. A total of 483 patient studies were reviewed. For each, the CT dose-length product was used to estimate radiation dose to the patient as a result of the whole body X-ray CT component of the PET/CT study. The net injected FDG dose was used to calculate the whole body effective dose based on ICRP recommendations. Dose calculations were also modified to take into account individual patient weight. The total effective dose received by each patient was taken as the sum of the PET and CT components of the study. The mean effective dose from the CT component of the diagnostic study was found to be 8.2 mSv (3.4–23.4 mSv), for a CT protocol of 120 kV_p and effective tube current–time product of 80 mAs with automatic exposure control. For an average injected FDG activity of 304 MBq the mean PET effective dose was found to be 6.3 mSv when using the ICRP standard models, or 6.0 mSv when scaling effective dose to individual patient weight or patient blood volume. The average total effective dose across the entire patient cohort for a combined PET/CT study was found to be ~14.5 mSv (9.6–29.8 mSv). Low-dose protocols for whole-body PET/CT scanning result in an effective radiation dose to the patient of approximately 14.5 mSv. Additional reductions through the use of iterative CT reconstruction and optimized low-dose FDG protocols could see total effective doses for whole-body PET/CT fall to below 10 mSv.     

Reconstruction of the inhalation dose in the 30-km zone after the Chernobyl accident.

Due to lack of measurements of activity concentrations in air, the assessment of the inhalation dose of the population evacuated from the 30-km zone after the Chernobyl accident is not possible from continuous filter measurements. Since the evaluation of the inhalation dose in each settlement of the zone is of great interest for epidemiological purposes, an approach was chosen that utilizes the available data on ground deposition of 137Cs, a recently performed best estimate of the radionuclide vector and its spatial distribution as well as the radionuclide dependent deposition velocity. The derived inhalation dose values in the 30-km zone range between 3 mSv to 150 mSv effective dose for adults depending on the distance to the reactor site and the day of evacuation. For 1-y-old infants the values range between 10 to 700 mSv. In Chernobyl town, an effective inhalation dose of 25 mSv until evacuation day was assessed. Thyroid doses due to inhalation ranged from 0.02 to 1 Sv for adults, for 1-y-old infants from 0.02 to 6 Sv. The inhalation dose in each settlement of the 30-km zone is approximately 8-13 times higher than the external exposure in each settlement if evacuation of the settlement occurred at an early stage. For settlements with evacuation at a later stage (day 10 or later) the inhalation dose was about 50-70% higher than the external dose. The dominant contribution to the effective inhalation dose comes from 131I (about 40%) and tellurium and rubidium isotopes (about 20-30%). Despite high zirconium and cerium ground depositions, zirconium and cerium isotopes contribute rather little to the inhalation dose which is mainly due to the great particle sizes to which they are attached. The relative contribution of short-lived radionuclides is, despite higher activities than at greater distances, less than 5%.