~(201)TlCl放射化学纯度测定方法的选择

本文以同一批一价~(201)Tl和三价~(201)Tl为供试品,采用醋酸纤维薄膜电泳、纸电泳、预饱和层析及非饱和层析等不同方法进行比较,发现上述方法均能将氯化铊中一价铊和三价铊分离,且当~(201)Tl中含少量三价铊时,测得一价供试品中一价铊(~(201)Tl)分别为99.92％(CV0.06％)、99.75％(CV0.02％)、99.87％(CV0.09％)和99.84％(CV0.09％),数值接近。但是,当以三价铊(~(201)Tl)作为供试品时,各方法测得的三价铊(~(201)Tl)含量分别为26.83％(CV29.82％)、19.06％(CV40.69％)、90.88％(CV0.53％)和15.65％(CV35.90％)。实验表明,四个方法测定三价铊的结果很不一致。采用Na_2HPO_4-丙酮(10:90)为溶剂、并在层析前预饱和15分钟、再上行层析的方法,能有效地测出供试品中三价~(201)Tl,而且误差小、重复性理想。为此,上述方法作为~(201)TlCl放射化学纯度的测定方法是适宜的。     

氯化亚铊(~(201)Tl)注射液和~(203)Pb水溶液中杂质元素的ICP-AES法分析

氯化亚铊(~(201)Tl)注射液是诊断心肌梗塞、缺血等症的性能优越、获得广泛应用的放射性药物。一些发达国家均已相继试制成功,并大量生产以满足临床的需要。我所放射性氯化亚铊(~(201)Tl)注射液研制组利用本所回旋加速器所产生的30MV质子辐照天然铊靶而获得~(201)Tl。其核反应为:     

回旋加速器制备放射性氯化亚铊(~(201)Tl)注射液

本文叙述制备放射性氯化亚铊(~(201)Tl)注射液的方法。靶子为高纯金属铊片,装于具有水冷、气冷腔的2π靶室内,利用扇形聚焦回旋加速器所产生的30MeV质子进行辐照。靶片溶解后,联合使用液-液萃取和阴离子交换法进行化学处理,可同时获得无载体~(203)Pb。产品~(201)Tl核纯度大于99％(~(200)Tl～0.76％,~(202)Tl～0.04％),放化纯度大于98％,含铊量小于0.27×10~(-7)μg/Bq(1.0μg/mCi)~(201)Tl。化学杂质Fe、Al等均小于1ppm,~(201)Tl厚靶产额约为18.8MBq/μAh。产品经临床前药理试验、药检试验和临床试用,质量良好。     

回旋加速器制备放射性氯化铊(~(201)Tl)注射液

本文叙述了我国首次制备放射性药物氯化铊(~(201)Tl)注射液的方法。靶子加工成一定厚度     

放射性氯化铊(~(201)Tl)注射液的临床前药理研究

氯化铊(~(201)Tl)注射液在美、英、法、日及其他一些国家已先后生产供货,并成为心肌缺血性疾病诊断用的主要放射性药物。近年有人试用于肺癌和甲状腺癌等肿瘤的诊断,已取得一定的成功。根据我国政府药政部门的要求,对国外已用于临床的药物,在国内首次研制中     

PDB-18C6从金靶中分离~(199)Tl

~(199)Tl比~(201)Tl吸附剂量减少三分之一,探测效率改进两倍多。本文用二苯并-18-冠-6甲醛聚合物(PDB-18C6)从金靶中分离~(199)Tl。着重研究了粒度分别为80—90和140—200目时的PDB-18C6在不同溶剂中及冠醚树脂在盐酸溶液中对Tl(Ⅰ)、Au(Ⅲ)、Cu(Ⅱ)的络合作用;冠醚树脂的用量对Tl(Ⅰ)、Au(Ⅲ)、Cu(Ⅱ)络合作用的影响;AU(Ⅲ)离子存在下冠醚树脂对络合Tl(Ⅰ)离子的影响;淋洗剂浓度与淋洗效率的关系;冠醚树脂上Tl(Ⅰ)、Au(Ⅲ)、Cu(Ⅱ)的分离;Tl(Ⅰ)、Au(Ⅲ)的回收效率;冠醚树脂的再生;从α粒子能量为25-27MeV辐照的金靶中分离~(199)Tl等。     

一个新的~(201)Pb-~(201)Tl发生器的研制

本文描述了从母体~(201)Pb分离子体~(201)Tl的一种新方法。该法采用无机离子交换剂柱,先将靶物溶解液通过离子交换柱,~(201)Pb~(2+)吸附在无机离子交换剂柱上,其他离子,如Tl~(3+)、Cu~(2+)等不吸附而通过离子交换柱被除去,经过32小时,即当子体~(201)Tl生长达到高峰时,以0.1mol/lHCl(0.7％Cl_2)溶液淋洗~(201)Tl。研究结果表明,本发生器具有简单、快速、效果良好的特点。     

心肌显像剂~(99m)Tc-TBI和~(201)Tl的内照射辐射吸收剂量的计算和比较

用MIRD法及自编软件计算了~(99m)Tc-TBI和~(201)Tl的内照射辐射吸收剂量。~(201)Tl的吸收剂量与文献值相似。二者共同的临界器官是肾和胰,~(99m)Tc-TBI还有肝脏。3.7×10~7Bq ~(99m)Tc-TBI的吸收剂量仅为~(201)Tl的1/10左右,因此~(99m)Tc-TBI一次心肌显像用量可达3.7×10~3Bq甚至更高。这样高的活度能大大增加信息量,不仅可以增进心肌平面或断层影像的质量,而且可以满足多门电路心脏室壁运动显像的要求。这是~(99m)Tc-TBI的突出优点,尽管它在有些方面存在着不如~(201)Tl之处。     

回旋加速器辐照制备无载体~(203)Pb的研究

采用氧化铊靶和15MeV的氘束,通过~(203)Tl(d,2n)~(203)Pb核反应,产生出放射性同位素~(203)Pb。将辐照过的氧化铊靶经过一系列的放化分离程序,可以获得高纯的~(203)Pb示踪剂,铊的含量为～1μg/ml(最终产品为10ml)。~(203)Pb的化学回收率为71±5％。在本实验辐照条件下,辐照停止时~(203)Pb的核反应产额为180±36μCi/μA·h。     

用镀金靶在回旋加速器内束流装置中生产~(199)Tl

利用回旋加速器内束流装置上引出的。粒子束流强度可达150—200μA,能量在24—25 MeV,轰击用铜为衬底的镀金靶头。发生~(197)Au(α,2n)~(199)Tl核反应,产生(199)Tl。研究了从铜、金和镓中分离铊的条件。~(199)Tl与~(200)Tl的活度分别为2.3×10~5Bq和7.1×10~2Bq,即~(200)Tl占~(199)Tl总活度的0.29％。     

C_(60)衍生物的放射性碘标记

富勒烯Ｃ6 0 是由 60个碳原子组成的球型分子 ,包含 1 2个五元环和 2 0个六元环 ,直径为0 .71ｎｍ。独特的结构赋予了它特殊的物理、化学和生物性质。Ｃ6 0 是一个优良的电子接受体 ,通过光诱导产生单重态氧的效率高达 1 0 0 % ,被喻为“单重态氧的发生器”。它极易与游离基反应 ,又被喻为“吸收游离基的海绵”。它具有 3 0个双键 ,可以发生许多有机反应 ,连接各种化学药物 ,是药物设计的理想载体[1] 。Ｃ6 0 仅溶于一些非极性和弱极性的有机溶剂 ,在水等极性溶剂中不溶。富勒烯作为药物载体 ,首先要制成水溶性衍生物。更为重要的是还必须了…     

~(201)Tl心肌灌注显像潘生丁试验在心肌梗塞诊断中的应用

本文介绍了103例心肌梗塞患者~(201)Tl心肌灌注显像潘生丁试验的结果,并对55例同时进行平面及断层显像的资料进行了分析。在断层即刻和延迟显像中灌注异常阳性率分别为93％及80％。诊断LAD、RCA和LCX各支病变的灵敏度为93％、89％及73％。51例有灌注异常的患者中有40例(72％)显示填充现象,提示同时存在有缺血性病变。结果显示~(201)Tl心肌灌注显像潘生丁试验不仅有助于心肌梗塞的诊断和病变部位及范围的了解,还有助于预后的估测和治疗方案的确定。     

Radiation dose to patients from radiopharmaceuticals (addendum 2 to ICRP publication 53)

A joint Task Group of ICRP Committees 2 (Doses from Radiation Exposures) and 3 (Protection in Medicine; lead Committee for this report) has prepared a compilation of data on radiation dose to patients from radiopharmaceuticals. The report provides biokinetic models, absorbed doses, and effective doses, using ICRP Publication 60 dosimetry, for 10 new radiopharmaceuticals: [Methyl-11C]thymidine; [2-11C]thymidine; 14C urea (incl. carbon dioxide and bicarbonate); 15O water; 99mTc HIG, Pertechnegas, Technegas, and tetrofosmin; and 111In HIG and octreotide. It also provides recalculated dose data for the 19 most frequently used radiopharmaceuticals from ICRP Publication 53, using ICRP Publication 60 dosimetry, viz. 18F FDG; 51Cr EDTA; 67Ga citrate; 75Se SeHCAT; 99mTc DMSA, DTPA, RBC, IDA, large colloids, WBC, MAA, non-absorbable markers, pertechnetate, and phosphates and phosphonates; 123I Hippuran and MIBG; 131I Hippuran and NP59; and 201Tl thallous ion. Printing errors detected in ICRP Publication 53 are also listed. Furthermore, the report reproduces with minor corrections and updates, and therefore supersedes, the information on 6 radiopharmaceuticals given in Addendum 1 to ICRP Publication 53: 3H neutral fat and fatty acids; 14C neutral fat and fatty acids; 68Ga EDTA; and 99mTc HM-PAO, MAG3, and MIBI. There is an integrated index to all radiopharmaceuticals treated in ICRP publications so far, including a listing of effective doses per unit activity administered to adults. This issue of the Annals of the ICRP also includes an Addendum to ICRP Publication 72 concerning age-dependent doses to members of the public from intakes of radionuclides.     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

Advanced three-dimensional two-phase flow simulation tools for application to reactor safety (ASTAR)

This paper summarizes the cumulative work undertaken in the frame of the EU shared-cost action “ASTAR Project”—the current status and future perspectives in the field of advanced numerical simulation of three-dimensional two-phase flow processes. This 3-year running project, which started in September 2000, involves seven partner institutes from around Europe. Specific emphasis is given to the further development of characteristic-based upwind differencing (also called “hyperbolic”) numerical methods and their application to transient two-phase flow. The paper summarizes the common basis adopted for the physical and mathematical modelling of two-phase flow in the form of a single-pressure “two-fluid” model and the various numerical solution techniques developed by the partners. Several benchmark exercises are presented which have been used as verification and assessment procedures for comparing the different modelling and numerical approaches. Comments on the suitability, accuracy, numerical stability, algorithmic robustness and computational efficiency serve as indicators for the possible extension of these methods to future code development activities. Two further tasks of the ASTAR project dealt with the production of high quality experimental field data in the LINX facility of PSI, for the validation of CFD models for two-phase bubbly flow, and the coupling of a two-phase CFD module with a system code. Details of these tasks have been published separately, and will not be recalled in this paper.     

Development of a false alarm free, Advanced Loose Parts Monitoring System (ALPS)

An Advanced Loose Parts Monitoring System (its acronym is ALPS) has been developed and installed on each unit of the Paks Nuclear Power Plant, Hungary. ALPS uses sophisticated methods to identify the events hidden in the quite extensive background noise of nuclear power plants. A classification algorithm based on an expert system, which is trained during the start-up period of each fuel cycle, helps to improve the false alarm rate. Thus the false alarm rate was reduced to a minimum, statistically below 1%. In practice, even the remaining “false alarms” were identified to be originating from other noise sources using ALPS. The main principles of ALPS are presented. It is demonstrated, that even weak signals, comparable with the resolution of the analog-digital board, i.e. comparable with detection noises, can be identified at high certainty. Other events like vibration of the shaft of motor operated isolating valves have been identified by ALPS. Furthermore, experiences gained during the installation period are also discussed.     

Dependence of the NaI(Tl) Pulse Shape on Thallium Concentration and Temperature

The pulse shape of ?-induced photopeak scintillations in NaI(Tl) has been measured as a function of temperature for several standard commercial crystals and for crystals containing known thallium concentrations. A detailed analysis of the data indicates that the first two microseconds of the pulse is characterized by at least nine separate decay processes. Four of these are attributed to one radiative and three metastable states associated with a thallous ion. Two fast processes are attributed to emission characteristic of pure NaI while two others are associated with high thallium concentration. Energy transport is suggested as the ninth process.     

Uranium Extraction from Sea Water with Composite Adsorbents, (II)

A composite hydrous oxide, prepared from the mixed solution of titanium tetrachloride and ferrous chloride by addition of sodium hydroxide solultion, was investigated because of its rather high uranium adsorption capacity and its magnetic property. Results obtained may lead to easier handling of adsorbent species in the extraction of uranium from sea water.

The uranium adsorption capacity of the composite hydrous oxide was measured using sea water to which a small amount of uranyl chloride was added. The initial uranium concentration was 10.1 μg/l. Physical and chemical properties, such as specific surface area, mean pore radius and amount of surface OH groups, were also measured. The composite hydrous oxide was found to be composed mainly of relatively small particles of anatase and large particles of magnetite. Uranium adsorption capacity reaches its maximum when the precipitation temperatures are 50–70°C. The capacity of the composite hydrous oxide was found to be closely related to the mean pore size and the amount of surface OH groups.     

SCALE calculation for evaluation of spent fuel condition during long-term storage

Experiences with an advanced spent nuclear fuel management in Slovakia are presented in this paper. The evaluation and monitoring procedures are based on practices at the Slovak wet interim spent fuel storage facility in NPP Jaslovské Bohunice. Since 1999, leak testing of WWER-440 fuel assemblies were completed using a special leak tightness detection system developed by Framatome-anp, “Sipping in Pool”. This system utilized external heating for the precise defects determination.Optimal methods for spent fuel disposal and monitoring were designed. A new conservative factor for specifying of spent fuel leak tightness is introduced in the paper. Limit values of leak tightness were established from the combination of SCALE4.4a (ORIGEN-ARP) calculations and measurements from the “Sipping in Pool” system. These limit values are: limiting fuel cladding leak tightness coefficient for tight fuel assembly – k_FCT(T) = 3 × 10⁻¹⁰, limiting fuel cladding leak tightness coefficient for fuel assembly with leakage – k_FCT(L) = 8 × 10⁻⁷.