共查询到20条相似文献,搜索用时 31 毫秒
1.
Rubel Chakravarty Meera Venkatesh Ashutosh Dash 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):45-51
A novel electrochemical process to avail clinical grade 99mTc from (n,γ)99Mo has been demonstrated. The electrochemical parameters were optimized to maximize the 99mTc yield with minimal 99Mo contamination. 99Mo/99mTc generators containing up to 29.6 GBq (800 mCi) 99Mo were developed and their performance were extensively evaluated for 10 days without changing the operating conditions.
Very high radioactive concentration of 99mTcO4
− of acceptable quality, commensurate with hospital radiopharmacy requirements could be availed from the system with >90% yield.
The compatibility of the product for the formulation of 99mTc labeled radiopharmaceuticals such as 99mTc-DMSA and 99mTc-EC was found to be satisfactory in terms of high labeling yields. The proposed route represents an important step for enhancing
the scope of accessing clinical grade 99mTc from low specific activity (n, γ)99Mo. 相似文献
2.
Yong Yi Peng Zhou Guangshan Liu 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(1):157-162
The atmospheric deposition fluxes of 7Be, 210Pb and 210Po at Xiamen were measured. The samples were collected from March 2004 to April 2005 and the sampling period was one month.
The 7Be and 210Pb activity were measured using HPGe γ-spectrometer after concentration using Fe(OH)3 co-precipitation method. The 210Po was counted with an α-spectrometer after the sample was digested and spontaneous plated onto a silver planchet. At Xiamen,
the atmospheric deposition fluxes of 7Be varied between 0.11 and 2.93 Bq·m−2·d−1 and the average was 1.64 Bq·m−2·d−1; 210Pb fluxes varied between 0.04 and 0.85 Bq·m−2·d−1, and the average was 0.51 Bq·m−2·d−1; 210Po fluxes varied between 0.002 and 0.133 Bq·m−2·d−1, and the average was 0.061 Bq·m−2·d−1. There were positive correlations between the deposition fluxes of 7Be, 210Pb or 210Po and the amount of precipitation. The residence time of aerosols varied between 6.0 and 54.0 days with a mean of 27.1 days,
which were calculated by 210Po/210Pb fluxes ratios. 相似文献
3.
A. Amekudzie O. Adukpo J. Annkah A. Faanu G. Emi-Reynolds 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(3):795-800
As part of monitoring the exposure of the Ghanaian public to natural radioactivity, radioactivity concentrations in titanium
enamel frits use for coating, spraying and decorating steel bowls were investigated. Samples collected from Ghana Utensil
Manufacturing Company in Ghana were analyzed using γ-ray spectrometry with a high purity germanium detector. The samples were
found to contain an average absorbed dose rate of 509.38 nGy h−1, while an average annual effective dose was calculated to be 2.50 mSv. 相似文献
4.
S. Anilkumar A. K. Deepa K. Narayani A. K. Rekha P. V. Achuthan G. Krishnamachari D. N. Sharma 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(1):161-166
The migration of 237Np in an undisturbed Chinese loess column was investigated by direct γ-ray method. The column was taken from a field test site and installed in a laboratory simulation hall. Radionuclide 237Np in the form of neptunium nitrate, mixed with quartz, was introduced into the column and covered with loess. Artificial
rainfall was applied to the column for about 3 years and, the counting rates of 237Np in the column from 56 to 616 days at different vertical positions were detected with a γ-ray detection system. Based on the counting rates of 237Np in the simulation column at different vertical positions and the distance from the source layer, the relationship of the
mass center of 237Np in the column at different experimental periods to the experimental time was established, C
m = 0.36 log(t)-2.75. Here C
m is the mass center of 237Np in the column, cm, and t is the experimental time in days. Based on this relationship, the mass center of 237Np for the 1,073-day experiment was predicted and compared to that obtained with the final destructive method. The good agreement
between the prediction and the experimental values indicates that the direct γ-ray method could be used to predict the migration of strongly adsorbed radionuclides such as 237Np in environmental media with the help of laboratory simulation columns. 相似文献
5.
T. Belgya 《Journal of Radioanalytical and Nuclear Chemistry》2008,276(3):609-614
The 14N(n,γ)15N reaction is a primary γ-ray source for high energy calibration of detectors. The relative γ-ray-intensities of 15N and the relative γ-ray detection efficiency function have been simultaneously determined up to 10 MeV from γ-peak areas
alone. Absolute γ-ray-intensities were obtained with proper renormalization to known absolute intensity. The influence of
these new intensity values are assessed for use in PGAA. Any consistently used set of calibration intensities applied in the
creation of library values and for analysis do not influence the concentrations. Contrary to this, quantities based on sums
of γ-ray cross sections may provide different answers with the new 15N intensities and they give means to validate them. 相似文献
6.
Z. Y. Chen F. Xie X. H. Wang Y. F. Chang Z. B. Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(1):257-261
A method of efficiency calibration for the measurement of 88Kr and 138Xe by HPGe γ-spectrometer is proposed in the present paper. The question for the efficient calibration is, how to achieve
homogeneous sources of 88Kr-88Rb and 138Xe-138Cs. The fission product gases were obtained by irradiating a precisely measured amount of U3O8 (90% 235U) filled in a quartz glass ampoule. Source cell was first filled up with stearic acid, and then the fission product gases
were charged into it. Xenon and krypton are not adsorbed on stearic acid, therefore, homogeneous sources of 88Kr-88Rb and 138Xe-138Cs can be prepared. The results of the experiment demonstrate that the method is feasible and successful. 相似文献
7.
Ashok Behera Kakali De Susmita Chandra Sankha Chattopadhyay Mridula Misra 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):123-129
In vivo imaging of tumours using radiolabelled somatostatin (SST) analogues has become an accepted clinical tool in oncology.
HYNIC-Tyr3 octreotide and Tyr3 octreotide were synthesized by FMOC solid-phase peptide synthesis using a semi-automated synthesizer. These were analyzed
and purified by RP-HPLC, mass spectroscopy, IR spectroscopy, 1H NMR and 13C NMR. The prochelator 6-BOC-HYNIC was also synthesised and characterised indigenously. HYNIC-Tyr3 octreotide was labelled with 99mTc using Tricine and EDDA as coligand by SnCl2 method. Labelling with 99mTc was performed at 100 °C for 15 min and radiochemical analysis by ITLC and HPLC methods. The radiochemical purity of the
complex was over 98% and log p value was found to be −1.27 ± 0.12. The stability of radiolabelled peptide complex was checked at 37 °C up to 24 h. Blood
clearance and protein-binding study was also performed. In vivo biodistribution studies in rat showed uptake of 99mTc-HYNIC-TOC in kidney than any other organs. The blood clearance was faster with rapid excretion through kidneys and relatively
low uptake in liver. 相似文献
8.
Zidan Mohamed M. Houmani Amran Ab. Majid Shahidan Radiman Zaharudin Ahmad 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(2):271-277
226Ra is a member of the 238U natural decay series and is one of the most important isotope to be determined among the naturally occurring nuclides in
environmental samples. In order to evaluate the radiation dose from 226Ra, it is important to know its mobility in different types of soils. The aim of the present study is to quantify the influence
of physico-chemical soil properties on 226Ra adsorption. The distribution coefficients (K
d-value) of 226Ra in Selangor soil series samples were measured in one core, at three depth levels to evaluate the adsorbability of 226Ra. The soil samples were spiked with 226Ra tracer and the activities of 226Ra in the separated phase from batch sorption test were measured by a low background but high efficiency well-type HPGe detector.
Several physico-chemical soil properties were also characterised for each soil samples. Pearson’s correlation and stepwise
multiple regression test were applied at the 0.05 level of significance throughout all analysis to determine the relationships
and influences between distribution coefficients (K
d-value) of 226Ra with physicochemical soil properties for the Selangor soil series. The observed K
d value was in the range of 50.55–172.28 mL g−1 (mean: 93.20 ± 46.99 mL g−1). The regression showed that the highest positive correlations were observed for organic matter (OM) and cation exchange
capacity (CEC) (r = 0.96**, 0.81**, respectively) with K
d-values. The results indicate that the stepwise multiple regression model incorporating the soil’s OM and CEC accounts for
98% of the variability in distribution coefficients of 226Ra. 相似文献
9.
Y. Yang J. X. Zhang J. J. Wang L. Zhu 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(1):31-36
To develop potential new Tc radiopharmaceuticals, a novel compound [99mTc(CO)2(NO)(EHIDA)]0 (EHIDA: 2,6-diethylphenylcarbamoylmethyliminodiacetic acid) has been prepared by reacting [99mTc(CO)3)(EHIDA)]− with NOBF4 both in water and acetonitrile. The conversion of [99mTc(CO)3)(EHIDA)]− to [99mTc(CO)2(NO)(EHIDA)]0 was supported by TLC, HPLC and eletrophoresis. The radiochemical purity (more than 99%) was proved by TLC and HPLC. The biodistribution
in mice demonstrated that [Tc(CO)2(NO)(EHIDA)]0 showed higher uptake in blood, kidney and lung (15 min, blood: 19.24±2.95; kidney: 13.61±3.49; lung: 10.81±1.09.) but a lower
uptake in liver (15 min, 5.73±0.74). The slower clearances (120 min, blood: 12.75±1.34; kidney: 13.61±3.49) from blood and
kidney were also found. This research describes two methods for the conversion of [99mTc(CO)3]+ into [99mTc(CO)2)(NO)]2+ by using NOBF4 as the source of NO+ both in organic solvent and water. The latter method offers the possibility to introduce the NO-group in high yield in water. 相似文献
10.
Lixiong Wang Tongzai Yang Zonghua Xiong Lei Tang Yanqiu Yang Liang Yang 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(1):111-116
Technetium-99 is one of several long-lived fission products which, when detected in the environment can give an indication
of a specific nuclear activity. The most sensitive analytical technique for 99Tc yet reported is by isotopic dilution mass spectrometry with technetium-97 as the yield tracer. A method for the preparation
of 97Tc is reported in this paper. 97Tc was obtained by irradiation of a sample of natural ruthenium metal in a high flux reactor. After cooling for 2 years, the
technetium was isolated from the sample by technique combining; deposition, solvent extraction, and ion-exchange chromatography
techniques. 99mTc and 103Ru were used as radio-tracers for the process. The results showed that more than 70% of the Tc was recovered the decontamination
factor is more than 2.3 × 107. The 97Tc was calibrated by isotope dilution mass spectrometry with 99Tc as the yield tracer. The final yield was 29.56 μg of 97Tc suitable for use as a mass spectrometric spike (weight % 97Tc spike: 97Tc, 84.77%; 98Tc, 15.03%; 99Tc, 0.20%). 相似文献
11.
Separation and purification of <Superscript>249</Superscript>Cf and <Superscript>245</Superscript>Cm
There is a need to provide radioactivity standards of the higher actinides in support of both decommissioning and remediation
activities as well as routine environmental analysis. In the case 249Cf, this will provide a useful calibration nuclide for both α-and γ-spectrometry as well as improving knowledge of the decay
scheme for this nuclide. There is anecdotal evidence to suggest that the chemical yield of americium and curium may differ
in radiochemical analysis. Thus, a chemical yield tracer of 245Cm may help to resolve this issue and will be suitable for both, suitable for use as a chemical yield tracer for both α-particle
spectrometry and mass spectrometry. An aged source of 249Cf was used as the source material for the separation of these two nuclides by cation-exchange, using 2-hydroxy-2-methyl-propanoic
acid at controlled pH as an eluant, 249Cf being eluted before the 245Cm daughter. The purity of both nuclides was measured by γ-ray spectrometry. 相似文献
12.
D. A. Haas S. R. Biegalski K. M. Foltz Biegalski 《Journal of Radioanalytical and Nuclear Chemistry》2008,277(3):561-565
In support of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), improvements have been made to the model of the Automated
Radioxenon Sampler/Analyzer (ARSA) β-γ coincidence detector for radioxenon monitoring. MCNPX is used to simulate the detector
response for all the electrons and photons emitted from 131mXe, 133Xe, 133mXe, 135Xe, and 137Cs signals. A MatLab code was written to incorporate the MCNPX results in the calculation of β-γ coincidence spectra. These
will aid in the development of the Spectral Deconvolution Analysis Tool (SDAT)1 and to calibrate β-γ coincidence systems. The models developed for this work include improvements over previous models in
their ability to address Compton scattering in the β-cell, and the β-distribution offset in the 31 keV γ-ray region for 133Xe. 相似文献
13.
A. T. Abdul Rahman A. T. Ramli 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(3):653-657
A survey was carried out to determine terrestrial gammaradiation dose rates, the concentration level of 238U and 232Th and α and β activities for the surface soil in Ulu Tiram, Malaysia A 125 measurements were performed using a NaI(T1) gamma-ray
detector with crystal size of 1″ × 1″ on 15 soil samples collected from the site area about 102 km2
238U and 232Th concentrations were determined in soils by using hyper pure germanium (HPGe) gamma-ray spectrometry. The activity of α
and β from the surface soil was counted by using alpha beta counting system. The average value of 238U and 232Th concentrations in soil samples collected are 3.63±0.39 ppm within the range of 1.74±0.20 to 4.58±0.48 and 43.00±2.31 ppm
within the range of 10.68±0.76 to 82 10±4.01 ppm, respectively. The average estimate of α and β activity in soil samples collected
are 0.65±0.09 Bqg−1 and 0.68±0.08 Bqg−1, respectively. The average of terrestrial gamma-radiation dose rates measured in Ulu Tiram was found to be 200 nGy h−1, within the range of 96 to 409 nGy h−1. The population weighted outdoor annual effective dose was 1.2 mSv. 相似文献
14.
Yanyan Kong Xingqin Zhou Guoxian Cao Xijie Xu Meifen Zou Xiaofeng Qin Rongjun Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):93-101
Pyrroloquinoline quinone (PQQ), an essential nutrient, antioxidant, redox modulator and nerve growth factor found in a class
of enzymes called quinoproteins, was labeled with 99mTc by using stannous fluoride (SnF2) method. Radiolabeling qualification, quality control and characterization of 99mTc-PQQ and its biodistribution studies in mice were performed and discussed. Effects of pH values, temperature, time and reducing
agents concentration on the radiolabeling yield were investigated. The quality control procedure of 99mTc-PQQ was determined by thin layer chromatography (TLC), radio high-performance liquid chromatography (RHPLC) and paper electrophoresis
methods. The average radiolabeling yield was 94 ± 1% under optimum conditions of 0.99 mg of PQQ, 30 μg of SnF2, 0.5 mg of ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) and 18.5 MBq of Na99mTcO4 at pH 6 and 25 °C with a response volume of 1 ± 0.1 mL. 99mTc-PQQ was stable and anionic. Lipid–water partition coefficient of 99mTc-PQQ was −1.49 ± 0.16. The pharmacokinetics parameters of 99mTc-PQQ were t
1/2α = 18.16 min, t
1/2β = 100.45 min, K
12 = 0.013 min−1, K
21 = 0.017 min−1, K
e = 0.016 min−1, AUC (area under the curve) = 1040.78 ID% g−1 min and CL (plasma clearance) = 0.096 mL min−1. The dual-exponential equation was Y = 10.88e−0.038t
+ 5.21e−0.0069t
. The biodistribution of 99mTc-PQQ was studied in ICR (Institute for Cancer Research 7701 Burhelme Are., Fox Chase, Philadelphia, PA 1911 USA) mice. In
vitro autoradiographic studies clearly showed that the 99mTc-PQQ radioactivity accumulated predominantly in the hippocampus and cortex, which had a high density of N-methyl-d-aspartate Receptor (NMDAR). The enrichment can be blocked by NMDAR redox modulatory site antagonists-ebselen (EB) and 99mTc-PQQ is therefore a promising candidate for the molecular imaging of NMDAR. To date, however, there have been no studies
characterizing 99mTc-PQQ. 相似文献
15.
The autodegradation-resistant mutant thermolysins (TLNs), L155A (Leu155 to Ala) and L155S (Leu155 to Ser), were previously constructed by site-directed mutagenesis to enhance thermostability. These mutations suppressed
autodegradation at position 154–155, resulting in increased thermostability. However, a new autodegradation site became apparent
in these mutant TLNs, at position 155–156. In this study, further stabilization of the mutant TLNs to suppress this new autodegradation
was attempted by the substitution of Ile156 to Asp and Val (L155A-I156N, L155A-I156V, L155S-I156N, and L155S-I156V). SDS–PAGE analysis showed that the autodegradation
at 155–156 of all double-mutant TLNs was suppressed. Thermostability at 80 °C was enhanced in all double-mutant TLNs (half-life
at 80 °C: WT, 18.3 min; L155A, 25.0 min; L155S, 24.0 min; L155A-I156N, 60.8 min; L155A-I156V, 62.4 min; L155S-I156N, 93.3 min;
and L155S-I156V, 40.0 min), and k
cat/K
m values were: WT, 220; L155A, 240; L155S, 123; L155A-I156N, 62; L155A-I156V, 760; L155S-I156N, 240; and L155S-I156V, 520 min−1 mM−1. 相似文献
16.
Exploration and modification of data for k
0-PGAA (prompt γ-ray activation analysis) values used as standards for k
0 standardization are needed. An integrated system has been installed and calibrated in Hot Laboratories Center for PGAA, using
252Cf isotopic neutron source with neutron flux of 6.16E8 n/cm2 s. The prompt k
0-factors of about 12 elements were determined versus the 1951.1 keV γ-ray of the 35Cl, as well as analyzing crude oil and oil product samples. The concentrations of the elements in crude oil H, B, Mg, Al,
Na, Si, P, S, Cl, V and Cd were 1.18E5, 0.084, 5.48E2, 8.45E2 4.88E2, 1.62E2, 3.72E2, 8.2, 144.3, 393 and 209.2 ppm while
in oil product samples were 1.32E5, 5.87, 4.56E2, 4.22E2, 7.16E3, 699, 157, 8.74, 492.3, 61 and 198.2 ppm. Validation of the
k
0-PGAA was applied in analyzing standard IAEA reference material (soil-7) which give good agreement with the literature data.
The 252Cf neutron beam in radiation position was characterized by the cadmium-ratio method, and found that the cadmium ratio (f), was 160. 相似文献
17.
The analysis of 226Ra in natural waters can be tedious and time-consuming. For the determination and differentiation of activities of 226Ra and 222Rn in drinking water by γ-ray spectrometry a simple and fast method is presented. Activities of 226Ra > 0.5 Bq L−1 can be determined according to stabilization of the sample without further procedures. For a more sensitive detection sample
volumes of up to 5 litres are applicable by a rapid precipitation procedure without large expenditure. Further laborious enrichment
methods are not necessary. Thus, detection limits of 0.1 Bq L−1 can be obtained when using sample volumes of 5 litres. Therefore the method is suitable for the monitoring of radioactivity
in drinking water samples in accordance with the legal guidance of the European Union. 相似文献
18.
Mamdouh S. Masoud Amina A. Soayed Ahmed S. Elkholany 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(3):1123-1130
The reaction of 99mTc of different oxidation states (+7, +4) with 2-thiouracil and 5-nitrobarbituric acid have been studied at different temperatures,
pH and concentrations. The reaction mixtures have been analyzed at different times using thin layer chromatography (TLC) and
a radio detector to show the peaks at the plates. 99mTc is obtained from the Mo generators with oxidation state (+7). The use of SnCl2 as a reducing agent gave 99mTc with oxidation state (+4). It is very difficult to separate the complexes formed from the reactions in very small concentration.
The percentage of 99mTc and its oxidation state involved in the complexes can be determined. The labeling efficiencies (percentage of complex)
in the reaction of 99mTc+7 with 5-nitro-barbituric-acid increases mostly at pH 10. Both oxidation states of 99mTc(+7, +4) can be detected at pH’s 4 and 10, but at pH 4, the reduced form 99mTCO2, is more pronounced. At pH 7 no complexes were detected and most of 99mTc remains as 99mTCO4
−
. By increasing the ligand concentration, the labeling efficiencies of the complex increases. For the reaction of 99mTc of oxidation states (+4, +7) with 2-thiouracil at different temperatures and analytical times it is concluded that several
complexes with different Rf values were observed in equilibrium and most of these complexes were unstable. 相似文献
19.
M. Sadeghi P. Sarabadani H. Karami 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(2):297-303
Maghemite nano-particles were synthesized by a solid-state chemical reaction for its highly selective use as, cyclotron-produced,
109Cd (462.9 days) purification method of choice. 109Cd radiochemical separation starts with Ag activities precipitated with HCl 0.0015 M followed by, on a second step, 109Cd separation from Cu carrier and 65Zn (243.8 days) using Ca (NO3)2 0.01 M. Experimental parameters such, pH and sorbent concentration, on 109Cd extraction efficiency were investigated. Phase morphology, nanostructure and size of nano-particles were studied by X-ray
diffraction (XRD) and scanning electron microscopy (SEM). A 10–20 nm average grain size was derived from XRD line broadening
and SEM data. Heat treatment on Fe3+:Fe2+ ratios equal to 2:1, produced powders, resulting in tetragonal (maghemite) structure at 300 °C and rhombohedra (hematite)
at 600 °C. 109Cd chemical and radionuclidic purity were determined by ICP-AES and HPGe detector gamma-ray spectrometry. The overall recovery
and radionuclide purity were 80.0% from obtained 129.63 kBq/C MeV (70 kBq/μAh) initial activity and 91.4%, respectively. 相似文献
20.
Heung N. Lee S. W. Kim M. G. Hur S. D. Yang W. H. Kim K. Y. Jee 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):617-620
3H and 14C Measurements of the dry active waste (DAW), such as the cotton, paper, and vinyl, generated from a nuclear power plant (NPP)
were conducted with wet oxidation using open vessel equipment based on simulation results. The recovery efficiency with the
simulated samples was around 93% with a relative standard deviation (RSD) of 1–3%. A liquid scintillation counter (LSC) was
used for counting and adjusted to a quenching correction curve. The counting value was evaluated for the minimum detectable
activity (MDA), which was found to be about 4 × 10−1 Bq/g for 3H and 2 × 10−2 for 14C when approximately 5 g of the samples were measured. The measured DAW samples for the cotton, paper, and vinyl generated
from NPP achieved of RSD values of 25, 25, and 60%, respectively, for 3H and 0–50% for 14C. 相似文献