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2.
本文综述了目前部分放射性核素迁移研究进程,介绍核素迁移的机理、概要介绍研究方法与进展,并指出今后核素迁移研究的发展方向。 相似文献
3.
LUO Quan-Yong CHEN Li-Bo YU Yong-Li LU Han-Kui ZHU Rui-Sen 《核技术(英文版)》2005,16(4):214-216
To monitor the extent and the duration of lymphocyte subset changes in patients with thyroid carcinoma undergoing therapeutic ^131I administration, the percentage of lymphocyte subsets were serially analyzed before and after ^131I treatment. In patients who received 1850 MBq of ^131I for ablation of thyroid remnants, only tor NK cells and B cells showed a significant reduction. In patients received 3700 MBq of ^131I for treatment of local lymph node metastases, NK cells, B cells and CD4+ were found decreased. In patients received 7400 MBq of ^131I for treatment of distant metastases, NK cells, B cells and CD4+ and CD8+ were all affected. However, there is no significant reduction compared to the baseline in the percentage of all lymphocyte subsets three months after ^131I treatment. The results show that the sensitivity of lymphocytes to ^131I internal radiation depends upon lymphocyte phenotype and ^131I activity. The immunosuppression effects are temporary and reversible. 相似文献
4.
为评价99Tcm(V)二巯基丁二酸钠(DMSA)显像和99Tcm枸缘酸(Citrate)显像在骨转移癌和骨及骨关节炎症诊断中的意义,对骨转移癌患者和骨及骨关节炎症患者各18例分别进行99Tcm亚甲基二膦酸(MDP)、99Tcm(V)DMSA和99TcmCitrate全身显像,并比较了它们的显像结果。18例经病理学、CT或MRI证实有骨转移癌的患者,99TcmMDP显像共检出64个病灶,99Tcm(V)DMSA显像显示在与99TcmMDP显像相同部位同检出49个病灶,而99TcmCitrate显像仅检出1个病灶。18例经细菌学、CT或MRI证实的骨及骨关节炎症患者,99TcmMDP显像共检出22个病灶,99Tcm(V)DMSA显像显示在与99Tcm MDP显像相同部位同检出17个病灶,99TcmCitrate显像检出16个病灶。本组病例99Tcm(V)DMSA显像诊断骨转移癌的灵敏度为76.56%,特异性为22.73%; 99TcmCitrate显像诊断骨转移癌的灵敏度仅为1.56%,特异性为27.27%。99Tcm(V)DMSA显像诊断骨及骨关节炎症的灵敏度为77.27%,特异性为23.44%;99TcmCitrate显像诊断骨及骨关节炎症的灵敏度为72.73%,特异性为98.44%。以上结果表明,99Tcm(V)DMSA显像在诊断骨转移癌和骨组织炎症时应该慎重,因为它不能区分骨组织的良恶性病变性质,其对骨组织的良恶性病变性质的鉴别诊断应排除外骨组织炎症、骨折等骨组织良性病变的干扰。而99TcmCitrate 相似文献
5.
The time scales required for nuclear waste disposal are very large compared with those for other engineering endeavors. Because of this, there are many uncertainties associated with the quantitative performance assessment of canisters containing high-level radioactive waste in a waste form. Multiple lines of evidence can be helpful in building confidence in the long-term behavior (corrosion and dissolution) of the canister and waste form. These lines of evidence are derived from long-term supports and probabilistic models and developed based on shorter term tests, bounding and conservative approaches, and available observations on natural analogs. This paper presents the progress made for important lines of evidence considered in quantitatively assessing radionuclide release behavior from canisters and waste forms. This paper considers risk-significant issues for canisters and waste forms (i.e., risk informed approach) in the probabilistic performance assessment of the disposal system which has also other components such as geology and hydrology. 相似文献
6.
贵州省土壤中天然放射性核素含量调查 总被引:1,自引:0,他引:1
本文报告贵州省土壤中天然放射性核素含量调查结果。全省共采集318个土壤样品,样品中核素的测定采用放化分析方法。结果表明,贵州省土壤中天然放射性核素含量,按各类土壤面积加权平均值为:~(238)U,45.6Bq·kg~(-1)(范围3.2—123.1Bq·kg~(-1));~(232)Th,41.3Bq·kg~(-1)(8.3—88.0Bq·kg~(-1));~(226)Ra,71.4Bq·kg~(-1)(3.7—226.1Bq·kg~(-1));(~(40)K,350.0Bq·kg~(-1)(23.7—802.6Bq·Kg~(-1)),属正常水平。 相似文献
7.
本文报告了1984年包头地区水体中天然放射性核素浓度调查结果,黄河包头段的浓度范围分别是:U,13.8~80.5Bq·m~(-3);Th,0.30~1.72Bq·m~(-3);~(226)Ra,21.1~83.7Bq·m~3;~(40)K,99.6~114.1Bq·m~(-3)。其它水体中的浓度范围分别是:U,15.0~119.4Bq·m~(-3);Th,0.19~1.11Bqm~(-3);~(226)Ra,19.4~203.9Bqm~(-3);~(40)K,24.9~469.3Bqm~(-3)。 相似文献
8.
概述了国际放射性核素监测系统中对放射性核素数据在测量过程的安全认证的要求,在推导并模拟铀、钍系衰变链中的相应子体和^7Be等核素从取样至测量过程中放射性活度变化规律以它们比值的基础上,建立样品取样测量运动及认证模式,在计算机拟合的基础上给出了^97Zr、^137Cs、^140Ba等与CTBT监测系统要求相关的裂变产物核素的最低检测限度, 相似文献
9.
内蒙古自治区土壤中天然放射性核素含量调查 总被引:2,自引:0,他引:2
本文报道内蒙古自治区土壤中天然放射性核素含量的调查方法和结果。全区共采集668个土壤样品,其中25×25 km 网格点样品334个。测量采用γ能谱法。调查结果表明,内蒙古自治区土壤中天然放射性核素含量按面积和样品数加权的均值分别为:~(238)U,29.76和28.60 Bq·kg~(-1);~(232)Th,33.42和34.89 Bq·kg~(-1);~(226)Ra,27.49和26.95Bq·kg~(-1);~(40)K,655.56和624.63 Bq·kg~(-1)。 相似文献
10.
A. Sakaguchi K. Kawai T. Imanaka S. Endo M. Yamamoto 《The Science of the total environment》2010,408(22):5392-5398
The first results on the feasibility of using 236U to reconstruct the level and spatial distribution of close-in fallout deposition from the Hiroshima A-bomb are reported, coupled with the use of global fallout 137Cs and 239 + 240Pu. The results for global fallout 236U in soil samples (0-30 cm) from Ishikawa prefecture showed that the deposition density of 236U from the global fallout can be accurately evaluated using AMS. All deposited 236U, 137Cs and 239 + 240Pu appeared to have been recovered using 30-cm cores. It was also noted from the depth profiles for 236U/239 + 240Pu and 236U/137Cs ratios that the downward behavior of 236U in the soil was apparently similar to that of 239 + 240Pu, while the 137Cs was liable to be retained in upper layers compared with 236U and 239 + 240Pu. The accumulated levels were 1.78 × 1013 atoms m− 2 for 236U, 4340 Bq m− 2 for 137Cs and 141 Bq m− 2 for 239 + 240Pu. The ratios of 236U/137Cs and 236U/239 + 240Pu were (4.10 ± 0.12) × 109 and (1.26 ± 0.04) × 1011 atoms Bq− 1, respectively. Results of 236U, 137Cs and 239 + 240Pu measurements for the seven soil cores (0-30 cm) from Hiroshima were discussed on the basis of ratios of 236U/137Cs and 236U/239 + 240Pu by comparing with those from the background area in Ishikawa, indicating that the global fallout dominates the current level of 236U accumulation in soil in the Black-rain area around Hiroshima after the Hiroshima bomb, and the contribution of the close-in fallout 236U produced by the Hiroshima A-bomb seems difficult to observe. 相似文献