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本文报道了新疆土壤中主要天然放射性核素的水平及所致居民外照射剂量的估算结果.土壤中天然放射性核素238U、232Th、226Ra和40K的活度,分别为36.9、39.4、36.2和648Bq·kg-1,所致居民外照射剂量为599μSv·a-1.137Cs的积分沉积密度为3.4kBq·m-2,所致居民外照射剂量为7.46μSv·a-1.合计606μSv·a-1. 相似文献
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本文调查了1983~1988年秦山核电站周围5km、20km, 80km范围内天然辐射外照射水平,20km范围内的土壤、食品和水中总β、90Sr,137Cs活度.估算了当地居民所受的外照射剂量和因食入90Sr、137Cs造成的内剂量.结果表明:5km,20km和80km的天然辐射外照射剂量相近,其人均年有效剂量当量1.0mSv,由食品所致居民90Sr和137Cs的年有效剂量当量分别为0.62μSv.a-1和0.19μSv.a-1,其结果与浙江省全省环境调查结果基本一致. 相似文献
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阿拉善盟是我国主要荒漠区之一,它位于内蒙古自治区最西端,东经79°11′~106°52′,北纬37°24′~42°25′。西起马宗山接甘肃,东抵贺兰山邻宁夏,南至河西走廊北山,北接蒙古共和国。海拔900~1500米,土地面积27万平方公里。全盟地广人... 相似文献
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本文报道了应用IN-90Ge(Li)γ谱仪测定的浙江省土壤中放射性核素水平的结果,238U、226Ra、232Th、40K的活度分别为45.8(25.3~112.8 )、39.4(14.5~126.8)、62.1(20.0~160.3)和620(237~1080)Bq·kg-1.室外1米高处的吸收剂量率为8.73×10-8Gy·h-1,室内为11.87×10-8Gy·h-1,γ辐射产生的居民人均年有效剂量当量为0.691mSv. 相似文献
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河北省放射卫生研究所 《中华放射医学与防护杂志》1988,8(S1):35-38
本文报道了采用萃取分光光度、硫酸钡载带-α测定、四苯硼钠重量法和银片自沉积法等分别测定了77样主要食品及饮水中的U、Th、226Ra、40K、210po和210pb的含量,并估算了U、Th、226Ra、40K、210po和210pb所致居民内照射剂量。 相似文献
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ECT所用的放射性^99mTc都在通风柜内标记。通风柜能屏蔽绝大部分射线。放射性药物在通风柜中对工作人员造成的外照射主要有两部分:一是对在里面操作的手臂形成照射;二是从操作手孔泄露出去的射线对人体局部或全身形成照射。由于被操作的放射性药物活度较大(如18.5GBq),这两部分对工作人员的剂量贡献不能忽略,应适当做好防护。 相似文献
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本文报道了外照射慢性放射病人(简称慢放病人)的剂量估算。根据射线工作量、X线机型号和容量、防护条件, 采用全国对x射线工作人员的剂量调查资料或对慢放病人的实际监测数据, 对从事x射线诊断的慢放病人进行了剂量估算。根据镭源活度、操作时间、离源距离, 及其镭疗的病人次数, 对早期从事谲疗工作的巨放病人进行了剂量估算。给出了29例慢放病人剂量的估算结果。其照射量(无受体)、红骨髓剂量、躯干平均剂量和有效剂量当量的平均值分别为7.5×10-2C·kg-11.3Gy、1.2Gy和1.6Sv。 相似文献
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本文报道了天津地区土壤中238U、226Ra、232Th和40K含量及其所致外照射剂量.结果表明:天津地区上壤中238U、226Ra、232Th和40K平均含量(Bq·kg-1),分别为16.0±6.6、28.9±11.6、36.9土10.0和468±123,地表1米高处平均空气吸收剂量率为5.7±1.1 × 10-3Gy·h-1,平均年有效剂量当量为405±8μSv. 相似文献
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With the aim of assessing potential public impact, preliminary investigations on tap waters collected from highly populated areas in Amman and Aqaba, Jordan were conducted by measuring gross alpha and beta activities as well as uranium and radium radionuclides. Gross activities deduced by liquid scintillation counting (LSC) were ranged in <50-250±23 mBq l−1 for alpha and <188-327±29 mBq l−1 for beta in Amman whereas higher concentrations were found in Aqaba. The results show that gross β activities are generally higher than the corresponding gross α activities and direct correlations between gross activities and total dissolved solids (TDS) exist. Moreover, the effect of TDS on gross analyses was studied and devoted to the optimization of LSC parameters. 234U, 235U and 238U concentrations were determined by alpha spectrometry after separation from the matrix by extraction chromatography and electroplating. 226Ra and 228Ra concentrations were measured, respectively, using de-gassing and gas proportional counter techniques. Uranium and radium concentrations do not reach the WHO recommended levels and the radioisotopic activity ratios were discussed. The associated age-dependent dose from water ingestion in Amman was estimated. The total dose for adults had an average value of 0.15 mSv y−1, which exceeds the WHO recommended limit of 0.1 mSv y−1 but still below the Jordanian limit of 0.5 mSv y−1. Although the Jordanian limit was exceeded for babies and infants, the lifetime risk assessment showed values as low as 10−4. Thereby it is concluded that tap waters of Amman is radiologically safe and pose no significant hazard to the public. Finally, a comparison of the investigated waters with worldwide data was made. 相似文献
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目的:开发便于快速估算环境放射性污染所致公众成员外照射剂量的应用软件。方法:基于国际放射防护委员会(ICRP)提供的数据,创建公众(成人与不同年龄组儿童)在不同环境暴露情形下的外照射剂量率转换系数数据库;在Windows操作系统内利用Python语言编写数据调用与计算程序,并借助PyQt工具包设计软件界面;为测试该软件的计算结果,试算了几种最可能出现放射性核素在3种环境暴露情景下所致公众成员的外照射剂量差异,并开展了合理性分析。结果:本研究开发软件可在带Windows系统的个人电脑上快速完成放射性核素污染外照射所致公众的器官当量剂量与全身有效剂量的估算,计算结果合理。结果表明,公众成员的年龄越小,器官当量剂量和有效剂量通常越大;对于相同活度浓度且达到放射性平衡
90Sr的土壤表面污染和水体污染,婴儿的有效剂量约为成人的6.08倍和2.51倍。
结论:本研究开发的软件具有操作简单、计算速度快等优点,适用于核事故应急等情形下快速估算公众成员外照射剂量。 相似文献
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Objective To investigate the concentrations of indoor radon (222Rn) and its daughter products as well as indoor thoron (220Rn) in selected houses in Yuhang district and Sanmen county,Zhejiang province,and estimate their annual effective doses to the population.Methods Solid state nuclear track detectors were used in selected dwellings in Yuhang district and Sanmen county,and the detectors were placed in bedrooms or living rooms.Without changing the ventilation habits of residents,These detectors were continuously placed from March to September in 2009.Results Indoor 222 Rn and 220Rn concentrations in low-rise buildings were the highest among all types of houses.The indoor concentration of 222 Rn had no relation with the building age (F = 0.53,P > 0.05),but that of 220 Rn was dependent on the building age (F = 3.56,P < 0.05).Moreover,the investigation demonstrated indoor 220 Rn concentrations in houses with no decoration were higher than in the houses decorated (t = 2.33,P <0.05).The average indoor concentrations of 222Rn and 220Rn in Yuhang district were 32.5 Bq/m3 and 314.3 Bq/m3,respectively,and the annual effective doses were 0.88 mSy and 0.42 mSv respectively.The average indoor concentrations of 222Rn and 220Rn in Sanmen county were 26.8 Bq/m3 and 399.5 Bq/m3,and the annual effective doses were 0.72 mSy and 0.53 mSv respectively.Conclusion The concentrations of indoor 222 Rn in some areas of Zhejiang province are at natural background level,and the concentrations of indoor 220Rn in rural areas are relatively higher.The total annual effective dose from 220Rn and its progeny was larger than that from 222Rn and its progeny by 50 percents. 相似文献
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目的 估算与分析我国航空机组人员职业照射水平,为加强其职业健康管理提供科学依据。方法 通过FlightAware网站采集我国客运量较大机场之间互相飞行的共计104条航线飞行数据,从覆盖我国机场数量、程序用户体验和实例计算航线有效剂量等方面,比较分析CARI、SIEVERT、PCAIRE和JISCARD-EX 4种宇宙辐射剂量估算程序。基于航线日志,择优采用CARI-7A估算我国航空机组人员宇宙辐射职业照射水平。结果 4种宇宙辐射剂量估算程序计算的不同太阳活动水平航线有效剂量差异均具有统计学意义(M=7.52~180.98,P<0.05); PCAIRE估算的2014年至2021年我国68条航线的年有效剂量显著高于CARI-7A的估算结果(Z= 2.52,P<0.05)。基于CARI-7A,估算获得2014—2021年我国航空机组人员宇宙辐射年有效剂量水平,其中乘务员为1.26(0.57~2.35) mSv,飞行员为1.03(0.47~1.92) mSv。我国部分高频次航线单次航班航空机组人员所受宇宙辐射有效剂量范围为0.57~6.88 μSv。结论 我国航空机组人员宇宙辐射职业照射水平符合国家标准要求,但高于医学、工业应用职业照射水平,仍需进一步加强航空机组人员职业照射剂量控制与职业健康管理。 相似文献
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Purpose The aim of the study was to explore the cause of the difference in the maximal rectal dose between the first and second high
dose rate (HDR) brachytherapy applications by comparing the thickness of the anterior rectal wall.
Materials and methods The rectal dose and the thickness of the anterior rectal wall were analyzed in 26 patients with prostate cancer. After undergoing
external beam radiation treatment with a total isocenter dose of 50 Gy, they were treated with HDR brachytherapy of 7.5 Gy/fraction,
two fractions daily. The interval between the first HDR brachytherapy session and the second was 5 h. The rectal doses were
directly surveyed during irradiation of the HDR brachytherapy. Thickening of the anterior rectal wall was measured at the
same level by axial computed tomography scans obtained before the first and second HDR brachytherapy applications.
Results The maximal surveyed rectal doses during the first and second HDR brachytherapy applications were 188 ± 51 cGy and 220 ± 35 cGy,
respectively (P < 0.01). The fluctuation ratio exceeded 1 in each case. The thickness of the anterior rectal wall before the first and second
HDR brachytherapy applications was 18.78 ± 4.34 mm and 14.95 ± 4.09 mm (P < 0.01), respectively. The fluctuation difference exceeded 0 in each case.
Conclusion The different rectal dose is attributable to thinning of the anterior rectal wall. The total rectal dose is within the range
of doses at risk of exerting a toxic effect on the rectum. 相似文献
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在事故受照射人员的医学处理中, 为了估计损伤程度, 要求提供受照者的剂量学参数, 这些参数应能较好的反映人体损伤效应。目前, 文献上使用的剂量表达方法是多种多样的, 我国的剂量学工作者对干细胞活存计权方法做了研究。研究结果表明, 对于骨髓型放射病剂量范围内的照射, 干细胞剂量可以表达全身造血组织的损伤程度。当然, 对于高度不均匀的外照射, 全身辐射损伤除了用干细胞剂量参数表达外, 还应给出受高剂量照射部证或某些关键器官的剂量。此外, 还对事故物理剂量测量方法做了实验研究。结果表明, 中国生产的4种手表红宝石具有良好的剂量学特性, 是一种比较实用的个人事故剂量计。 相似文献
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目的 研究氡析出对居室建材外照射剂量模型的影响,为准确评价建材放射性外照射危害提供依据。方法 分析建材中氡的析出机制,推导建材单位比活度226Ra所致外照射剂量率氡析出修正因子的数学模型,利用Matlab程序解析计算、探讨氡析出修正因子与扩散长度、氡面发射系数以及建材厚度的关系。计算、比较部分建材在修正与未修正氡析出影响下所致的吸收剂量率。结果 建材单位比活度226Ra所致吸收剂量率的氡析出修正因子与扩散长度、建材厚度不相关,与发射系数负相关,在数值上等于“1-FRn”(FRn为氡面发射系数)。在修正与未修正氡析出影响两种情况下,部分建材所致吸收剂量率的相对百分偏差为2.23%~10.02%。结论 建材氡的析出对其外照射辐射剂量模型有一定影响,可选取氡析出修正因子为“1-FRn”进行修正,从而更科学地评价建材外照射危害。 相似文献
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本文报道了用热释光方法监测的3124例放射工作人员所接受的外照射年剂量水平。年剂量最小者为0.2mGy, 最大者为70.0mGy, 均值为1.79mGy。按职业分类, 医用诊断X射线、核医学、放射治疗、工业探伤、地质物探、教学科研及其它人员的年剂量依次为1.95mGy、1.15mGy、0.9lmGy、2.11MGy、l.76MGy、1.76mGy, 0.65mGy、1.14mGy.95.9%的人员年剂量没有超过国家限值的3/10;89.8%人员的年剂量没超过限值的1/10。 相似文献
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目的 探讨将体型特异性剂量估算值(SSDE)用于估算冠状动脉CT血管成像(CTA)中患者器官剂量和个体有效剂量的可行性。方法 回顾性连续纳入冠状动脉CTA患者421例,均于第3代双源Force型CT采用前瞻性心电门控触发轴扫协议检查。通过Radimetrics计算患者水当量直径以计算每位患者的SSDE;使用Monte Carlo模拟估算患者扫描范围内器官的吸收剂量包括心脏、肺、肝和乳腺。使用国际放射防护委员会(ICRP)103报告的器官敏感加权系数,将患者主要敏感器官的剂量加权求和计算个体有效剂量。使用线性相关分析验证SSDE与器官剂量及个体有效剂量的相关性,并推导基于SSDE估算器官剂量和个体有效剂量的转换系数。使用平均差值比评价该估算方法的准确性。结果 容积CT剂量指数(CTDIvol)为(16.8±8.7) mGy,SSDE为(20.8±8.8) mGy,个体有效剂量为(4.4±2.9) mSv。基于SSDE估算器官剂量的线性拟合公式为:心脏Y=1.2X-6.4(R2=0.91,P<0.05,平均误差0.1%);乳腺Y=1.4X-7.4(R2=0.91,P<0.05,平均误差7.9%);肺脏Y=0.89X-4.6(R2=0.86,P<0.05,平均误差8.3%);肝脏Y=0.36X-1.8(R2=0.64,P<0.05,平均误差-17.9%)。基于SSDE估算个体有效剂量的线性拟合公式为:男Y=0.21X-1.2(R2=0.92,P<0.05,平均误差0.2%);女Y=0.39X-2.2(R2=0.93,P<0.05,平均误差1.7%)。结论 在冠状动脉CTA检查中通过SSDE和相应的转换系数可估算被照射器官吸收剂量和个体有效剂量,将有助于在临床工作中实现患者辐射剂量及风险的个性化评估和精准管理。 相似文献