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Applied Radiation and Isotopes

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https://www.readbyqxmd.com/read/28427834/doped-silica-fibre-thermoluminescence-measurements-of-radiation-dose-in-the-use-of-223-ra
#1
Bradley, S F Abdul Sani, A S Siti Shafiqah, S M Collins, R P Hugtenburg, H A Abdul Rashid, Nurul Najua Zulkepely, M J Maah
Using tailor-made sub-mm dimension doped-silica fibres, thermoluminescent dosimetric studies have been performed for α-emitting sources of (223)RaCl2 (the basis of the Bayer Healthcare product Xofigo®). The use of (223)RaCl2 in the palliative treatment of bone metastases resulting from late-stage castration-resistant prostate cancer focuses on its favourable uptake in metabolically active bone metastases. Such treatment benefits from the high linear energy transfer (LET) and associated short path length (<100µm) of the α-particles emitted by (223)Ra and its decay progeny...
April 14, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28431336/beam-induced-back-streaming-electron-suppression-analysis-for-an-accelerator-type-neutron-generator-designed-for-40-ar-39-ar-geochronology
#2
Cory Waltz, Mauricio Ayllon, Tim Becker, Lee Bernstein, Ka-Ngo Leung, Leo Kirsch, Paul Renne, Karl Van Bibber
A facility based on a next-generation, high-flux D-D neutron generator has been commissioned and it is now operational at the University of California, Berkeley. The current generator designed for (40)Ar/(39)Ar dating of geological materials produces nearly monoenergetic 2.45MeV neutrons at outputs of 10(8)n/s. The narrow energy range is advantageous relative to the (235)U fission spectrum neutrons due to (i) reduced (39)Ar recoil energy, (ii) minimized production of interfering argon isotopes from K, Ca, and Cl, and (iii) reduced total activity for radiological safety and waste generation...
April 13, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28431335/minimization-of-the-amount-of-kryptofix-222-khco3-for-applications-to-microscale-18-f-radiolabeling
#3
Ren Iwata, Claudio Pascali, Kazunori Terasaki, Yoichi Ishikawa, Shozo Furumoto, Kazuhiko Yanai
Conversion of aqueous [(18)F]fluoride to reactive [(18)F]fluoride is an important first step in the radiosynthesis of (18)F-labeled compounds by nucleophilic substitution. A versatile method for the rapid preparation of reactive [(18)F]fluoride by the combined use of an Oasis MAX cartridge and a methanolic solution of the Kryptofix 222-KHCO3 complex (K.222/KHCO3) was developed. The latter amount was optimized with the aim to keep it as low as possible while achieving recovery yields of [(18)F]fluoride comparable to those attained with the commonly used QMA cartridge...
April 13, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28437735/detective-quantum-efficiency-dqe-in-pet-scanners-a-simulation-study
#4
George E Karpetas, Christos M Michail, George P Fountos, Nektarios I Kalyvas, Ioannis G Valais, Ioannis S Kandarakis, George S Panayiotakis
The aim of the present study is to introduce the detective quantum efficiency (DQE) for the image quality assessment of positron emission tomography (PET) scanners. For this purpose, a thin layer chromatography (TLC) plane source was simulated using a previously validated, scanner and source geometry, Monte Carlo (MC) model. The model was developed with the Geant4 application for tomographic emission (GATE) MC package and reconstructed images obtained with the software for tomographic image reconstruction (STIR), with cluster computing...
April 12, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28434643/assessment-of-cell-death-mechanisms-triggered-by-177-lu-anti-cd20-in-lymphoma-cells
#5
E Azorín-Vega, E Rojas-Calderón, B Martínez-Ventura, J Ramos-Bernal, L Serrano-Espinoza, N Jiménez-Mancilla, D Ordaz-Rosado, G Ferro-Flores
The aim of this research was to evaluate the cell cycle redistribution and activation of early and late apoptotic pathways in lymphoma cells after treatment with (177)Lu-anti-CD20. Experimental and computer models were used to calculate the radiation absorbed dose to cancer cell nuclei. The computer model (Monte Carlo, PENELOPE) consisted of twenty spheres representing cells with an inner sphere (cell nucleus) embedded in culture media. Radiation emissions of the radiopharmaceutical located in cell membranes and in culture media were considered for nuclei dose calculations...
April 12, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28432929/performance-testing-of-the-neutron-flux-monitors-from-10kev-to-1mev-developed-for-bnct-a-preliminary-study
#6
Xingcai Guan, Masanobu Manabe, Shingo Tamaki, Fuminobu Sato, Isao Murata, Tieshan Wang
The neutron flux monitors from 10keV to 1MeV designed for boron neutron capture therapy (BNCT) were experimentally tested with prototype monitors in an appropriate neutron field produced at the intense deuterium-tritium neutron source facility OKTAVIAN of Osaka University, Japan. The experimental test results and related analysis indicated that the performance of the monitors was good and the neutron fluxes from 10keV to 1MeV of practical BNCT neutron sources can be measured within 10% by the monitors.
April 12, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28431337/a-possible-approach-to-14mev-neutron-moderation-a-preliminary-study-case
#7
D Flammini, R Pilotti, A Pietropaolo
Deuterium-Tritium (D-T) interactions produce almost monochromatic neutrons with about 14MeV energy. These neutrons are used in benchmark experiments as well as for neutron cross sections assessment in fusion reactors technology. The possibility to moderate 14MeV neutrons for purposes beyond fusion is worth to be studied in relation to projects of intense D-T sources. In this preliminary study, carried out using the MCNP Monte Carlo code, the moderation of 14MeV neutrons is approached foreseeing the use of combination of metallic materials as pre-moderator and reflectors coupled to standard water moderators...
April 12, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28427044/on-the-reverse-micelle-effect-in-liquid-scintillation-counting
#8
Youcef Nedjadi, Jean-Pascal Laedermann, François Bochud, Claude Bailat
This work looks into the tracks of electrons in nanoemulsive scintillating media using the Monte Carlo Geant4-DNA code which simulates event-by-event interactions of electrons in liquid water down to the eV, without resorting to the condensed history method. It demonstrates that the average number of micelles in which electrons deposit energy is quite large, increasing with their emission energy, decreasing with micelle size, and rising with micelle concentration. The probability of an electron ending its track in a micelle is found to be rather large and micelle size-dependent below 1keV, and approximating the aqueous fraction at higher energies...
April 12, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28427043/neutron-radiation-shielding-properties-of-polymer-incorporated-self-compacting-concrete-mixes
#9
Santhosh M Malkapur, L Divakar, Mattur C Narasimhan, Narayana B Karkera, P Goverdhan, V Sathian, N K Prasad
In this work, the neutron radiation shielding characteristics of a class of novel polymer-incorporated self-compacting concrete (PISCC) mixes are evaluated. Pulverized high density polyethylene (HDPE) material was used, at three different reference volumes, as a partial replacement to river sand in conventional concrete mixes. By such partial replacement of sand with polymer, additional hydrogen contents are incorporated in these concrete mixes and their effect on the neutron radiation shielding properties are studied...
April 12, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28411534/development-of-an-active-tritium-sampler-for-discriminating-chemical-forms-without-the-use-of-combustion-gases-in-a-fusion-test-facility
#10
Masahiro Tanaka, Hiromi Kato, Yukie Yamamoto, Chie Iwata
A new type of active tritium sampler that can discriminate between chemical forms in a fusion test facility without the use of combustion gases was developed. The proposed tritium sampler was operated using water vapour instead of combustion gases. To test the operation and performance of the device when water vapour is used, we evaluated the catalytic oxidation properties, and the evaporation and collection of water vapour under actual sampling conditions. The properties of the added water mass and the operation temperature of catalysts in the proposed sampling system were then determined...
April 8, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28411536/development-of-tritiated-nitroxide-for-nuclear-battery
#11
Johnny Russo, Marc Litz, William Ray, Gerald M Rosen, David I Bigio, Robert Fazio
Beta radioisotope energy sources, such as tritium ((3)H), have shown significant potential in satisfying the needs of a sensor-driven world. The limitations of current beta sources include: (i) low beta-flux power, (ii) intrinsic isotope leakage and (iii) beta self-absorption. The figure of merit is the beta-flux power (dPβ/dS in μWn/cm(2)), where an optimal portion of incident beta particles penetrates the semiconductor depletion region. Thus, the goal of this research was to identify a compound to contain a beta emitter that can permit beta-flux power of at least 0...
April 7, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28407496/study-of-the-wall-effect-of-the-sample-position-well-of-the-frisch-grid-ionization-chamber
#12
Huaiyong Bai, Zhimin Wang, Luyu Zhang, Haoyu Jiang, Yi Lu, Jinxiang Chen, Guohui Zhang
When measuring the charged particles using a Frisch-grid ionization chamber, the sample is usually placed at the bottom of a sample position well on the common cathode. Thus, there will be the wall effect of the sample position well and this will change the measured energy spectrum of the charged particles. The wall effect of the sample position well is proved to be noticeable by the present work using experiments and simulations.
April 7, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28433701/thyroid-monitoring-of-adults-and-children-after-reactor-accidents-with-a-new-dose-rate-measurement-device
#13
Oliver Meisenberg, Udo C Gerstmann
A specialized dose rate measurement device that was designed for monitoring the thyroid dose of children and adults after reactor accidents was tested. In measurements with neck phantoms and a human patient, the device was found to be capable of measuring the required low dose rates, even within increased ambient radiation. It is suitable for the application in emergency care centers.
April 6, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28427042/long-term-performance-assessment-of-hpge-detectors-used-in-the-neutron-activation-analysis-laboratory-of-ipen-cnen-sp-brazil
#14
G S Zahn, F A Genezini, R B Ticianelli, M Saiki
In this work, verification data for 11 HPGe detectors from two different manufacturers and three different intrinsic configurations were analyzed in respect to the stability of both the efficiency and resolution for the 122keV peak from (57)Co and the 1332keV peak from (60)Co. The results allow a discussion about the stability of these parameters over time (in some cases, almost 15 years), their sensitivity to imminent detector failures and their performance after a failure has been corrected; moreover, the results show a clear correlation between the manufacturer or configuration and the long-term performance of the detector...
April 6, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28433700/isotopic-characterization-and-thermal-neutron-flux-determination-of-a-pube-neutron-source
#15
Ravi Ankit Purty, Akanchha, Shikha Prasad
The Indian Institute of Technology Kanpur (IIT Kanpur) possesses a PuBe neutron source facility with an initial activity of 5 Ci, dated September 1966 (nearly 50 years ago). An understanding of the present activity and the rate of its change will allow implementation of proper radiological safety procedures and future radiological safety planning. Knowing the absolute neutron flux will help us in future neutron activation studies. These details are also important to ensure proper security precautions. In our work, we attempt to identify the isotopic composition to determine the rate of change of the source and the absolute thermal neutron flux of plutonium beryllium (PuBe) sample at IIT Kanpur...
April 5, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28432930/an-innovative-procedure-for-norm-scales-treatment-and-radionuclides-separation
#16
Jamal Al Abdullah, Mohammad Said Al-Masri, Yusr Amin, Hussam Khalily, Mohammad Ammar, Samer Nassour
The present study focuses on the development of a new chemical treatment method for naturally occurring radioactive materials (NORM) scale wastes from the oil industry. The method consists of three-stages, including the separation of oil using the Fenton oxidation process at room temperature, the complete dissolution of soluble and slightly soluble salts and separation of Ra and Pb isotopes. The proposed method can be considered as an innovative procedure for NORM scales treatment and radionuclides separation, which in turn support the radioactive waste management with economic benefits...
April 5, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28411537/longitudinal-monitoring-of-whole-body-counter-nai-tl-detector-efficiency
#17
R J Shypailo
Assessing accuracy of radiation counting systems over time is critical. We examined long-term WBC performance in detail. Efficiency factors for 54 detectors were updated annually over several years. Newer efficiency values were compared with baseline and with annual values. Overall system efficiency has declined (-1.9% over 3 yrs) and appears to be doing so at an increasing rate. Having more specific performance data on individual components can make the process of system maintenance and repair more straightforward and efficient...
April 5, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28411535/thermally-enhanced-tld-output-impacts-on-the-response-curve
#18
H A Soliman, Mohamed A Hassan, Enas Esmat, A M Sadek, Ahmed M Maghraby
Pre-irradiation background reading of thermoluminescent LiF dosimeters results in severe changes in the glow curve qualitatively and quantitatively. Current work focuses on the possible changes in the response of TLD-700 dosimeters after this effect. This work examines changes in the level of the glow curve as a whole and on the level of individual peaks as well. It was found that the response of TLD-700 dosimeters has increased by factors ranging from 20% to 44% in terms of area under the glow curve. Changes in individual peaks were examined by performing deconvolution for the glow curves...
April 5, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28410474/a-methodology-to-determine-natural-radioactivity-by-%C3%AE-spectrometry-without-using-calibrated-standard-samples
#19
Enrique R González, Raúl T Mainardi, Gabriela B Grad, Edgardo V Bonzi
When determining the radioactivity in materials by γ spectra, different processes are involved difficulting the fit. Besides, calibrated standard samples are necessary. In this work we propose a methodology to determine natural radioactivity using simulated γ spectra by Monte Carlo and without the use of calibrated standard samples. We applied this methodology to determine radioactivity of K 40 isotopes from a light salt sample. Then we applied this process in soil samples and the results where compared with the values obtained by an other laboratory...
April 5, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28395223/potassium-compounds-for-gamma-spectrometer-efficiency-verification
#20
E Eren Belgin, G A Aycik
Now-a-days several standard and well calibrated radioactive sources are available for gamma spectrometer efficiency calibration but at some situations, like lack of standard calibrators, in need of verification of standards or preparation a standard with the same properties with the interested sample, (40)K is a cheap and easily available radioisotope that could be used. In this study, eighteen different inorganic potassium compounds that have different potassium abundances, types of elements, densities and particle sizes were studied as efficiency verification sources...
April 5, 2017: Applied Radiation and Isotopes
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