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https://www.readbyqxmd.com/read/28048549/th-a-204-01-part-i-key-data-for-ionizing-radiation-dosimetry
#1
S Seltzer
: The ICRU is currently finalizing a report on key data for radiation dosimetry. This multi-year review has resulted in a number of recommendations regarding "fundamental" data that are used in dosimetry related to radiation therapy. This educational session will explain the background for the ICRU committee's work, the content and conclusions of the report and the impact on outputs, including NIST primary standards, ADCL calibration coefficients and clinical reference dosimetry. Parameters and beam modalities potentially affected by this report include: The mean excitation energy, I, for graphite, air, and water, The average energy required to create an ion pair in dry air (commonly referred to as W/e), The uncertainty in the determination of air kerma in kV x-rays The absolute value of Co-60 and Cs-137 primary standards and the dissemination of calibration coefficients, The determination of air kerma strength for Ir-192 HDR brachytherapy sources Ion chamber kQ factors for linac MV beams Ion chamber kQ factors for proton beams...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047887/th-a-204-02-part-ii-worldwide-radiation-metrology
#2
M McEwen
: The ICRU is currently finalizing a report on key data for radiation dosimetry. This multi-year review has resulted in a number of recommendations regarding "fundamental" data that are used in dosimetry related to radiation therapy. This educational session will explain the background for the ICRU committee's work, the content and conclusions of the report and the impact on outputs, including NIST primary standards, ADCL calibration coefficients and clinical reference dosimetry. Parameters and beam modalities potentially affected by this report include: The mean excitation energy, I, for graphite, air, and water, The average energy required to create an ion pair in dry air (commonly referred to as W/e), The uncertainty in the determination of air kerma in kV x-rays The absolute value of Co-60 and Cs-137 primary standards and the dissemination of calibration coefficients, The determination of air kerma strength for Ir-192 HDR brachytherapy sources Ion chamber kQ factors for linac MV beams Ion chamber kQ factors for proton beams...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046487/th-a-204-00-key-dosimetry-data-impact-of-new-icru-recommendations
#3
Ronald Tosh
: The ICRU is currently finalizing a report on key data for radiation dosimetry. This multi-year review has resulted in a number of recommendations regarding "fundamental" data that are used in dosimetry related to radiation therapy. This educational session will explain the background for the ICRU committee's work, the content and conclusions of the report and the impact on outputs, including NIST primary standards, ADCL calibration coefficients and clinical reference dosimetry. Parameters and beam modalities potentially affected by this report include: The mean excitation energy, I, for graphite, air, and water, The average energy required to create an ion pair in dry air (commonly referred to as W/e), The uncertainty in the determination of air kerma in kV xrays The absolute value of Co-60 and Cs-137 primary standards and the dissemination of calibration coefficients, The determination of air kerma strength for Ir-192 HDR brachytherapy sources Ion chamber kQ factors for linac MV beams Ion chamber kQ factors for proton beams...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046369/su-g-201-05-comparison-of-different-methods-for-output-verification-of-eleckta-nucletron-s-valencia-skin-applicators
#4
J Barrett, M Yudelev
PURPOSE: The provided output factors for Elekta Nucletron's skin applicators are based on Monte Carlo simulations. These outputs have not been independently verified, and there is no recognized method for output verification of the vendor's applicators. The purpose of this work is to validate the outputs provided by the vendor experimentally. METHODS: Using a Flexitron Ir-192 HDR unit, three experimental methods were employed to determine dose with the 30 mm diameter Valencia applicator: first a gradient method using extrapolation ionization chamber (Far West Technology, EIC-1) measurements in solid water phantom at 3 mm SCD was used...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/27930922/molecular-dynamics-simulations-of-cesium-adsorption-on-illite-nanoparticles
#5
Laura N Lammers, Ian C Bourg, Masahiko Okumura, Kedarnath Kolluri, Garrison Sposito, Masahiko Machida
The charged surfaces of micaceous minerals, especially illite, regulate the mobility of the major radioisotopes of Cs ((134)Cs, (135)Cs, (137)Cs) in the geosphere. Despite the long history of Cs adsorption studies, the nature of the illite surface sites remains incompletely understood. To address this problem, we present atomistic simulations of Cs competition with Na for three candidate illite adsorption sites - edge, basal plane, and interlayer. Our simulation results are broadly consistent with affinities and selectivities that have been inferred from surface complexation models...
March 15, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/27885075/suitability-of-portable-radionuclide-identifiers-for-emergency-incorporation-monitoring
#6
Roman Galeev, Gernot Butterweck, Markus Boschung, Bénédicte Hofstetter-Boillat, Eike Hohmann, Sabine Mayer
The suitability of portable nuclide inspectors for incorporation measurements were tested with three probes (LaBr3(Ce), NaI(Tl) and HPGe) differing in sensitive volume and energy resolution. The efficiencies for the measurement of whole-body and lung radionuclide burden were calibrated using a whole-body block phantom with traceable radionuclide sources of (60)Co, (133)Ba, (137)Cs, (152)Eu and (40)K. A standing geometry was chosen as it allows rapid positioning of persons for the measurements. Decision and detection limits were determined for the unshielded detector in a normal laboratory radiation environment according to ISO 11929 for (134)Cs, (137)Cs and (60)Co...
November 24, 2016: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/27878901/radioactive-cesium-and-potassium-in-cattle-living-in-the-zone-in-preparation-for-the-lifting-of-the-evacuation-order-of-the-fukushima-nuclear-accident
#7
Itaru Sato, Jun Sasaki, Hiroshi Satoh, Takahisa Murata, Kumiko Otani, Keiji Okada
To contribute to the reconstruction of livestock industry in Fukushima, radioactive cesium ((134) Cs, (137) Cs) and potassium ((4) °K) were measured in various tissues of beef cattle living in an area where the evacuation order will be lifted in the near future. Radioactive cesium concentration was less than 100 Bq/kg in most of the samples. Skeletal muscles and kidney had the highest concentrations of radioactive cesium, whereas the liver was lowest among samples, excepting blood. Radioactive cesium concentration in the sirloin, tenderloin and top round was significantly higher than that in the neck muscle...
November 23, 2016: Animal Science Journal, Nihon Chikusan Gakkaihō
https://www.readbyqxmd.com/read/27746518/carbon-cesium-and-iodine-isotopes-in-japanese-cedar-leaves-from-iwaki-fukushima
#8
Sheng Xu, Gordon T Cook, Alan J Cresswell, Elaine Dunbar, Stewart P H T Freeman, Xiaolin Hou, Helen Kinch, Philip Naysmith, David W C Sanderson, Luyuan Zhang
Japanese cedar leaves from Iwaki, Fukushima were analyzed for carbon, cesium and iodine isotopic compositions before and after the 2011 nuclear accident. The Δ(14)C values reflect ambient atmospheric (14)C concentrations during the year the leaves were sampled/defoliated, and also previous year(s). The elevated (129)I and (134,137)Cs concentrations are attributed to direct exposure to the radioactive fallout for the pre-fallout-expended leaves and to internal translocation from older parts of the tree for post-fallout-expended leaves...
2016: Journal of Radioanalytical and Nuclear Chemistry
https://www.readbyqxmd.com/read/27613705/shielding-design-for-a-cs-137-rod-type-standard-point-source-for-well-chamber-constancy-checks
#9
Mahsheed Sabet, David Cryer, David Waterhouse
Well type chambers are used for radioactive source calibrations in brachytherapy, but do not provide radiation shielding. Routine constancy checks on a well chamber are required between periodic secondary standard laboratory calibrations to ensure consistent device performance, and ultimately to ensure accurate patient dose delivery. In this work, a method is described to provide suitable shielding for a Cs-137 rod-type point source to enable use for constancy checks. A novel plunger-type shielded housing was designed and constructed for the Cs-137 source that when combined with a suitably shielded well-chamber container minimised user exposure during constancy checks...
September 9, 2016: Australasian Physical & Engineering Sciences in Medicine
https://www.readbyqxmd.com/read/27552123/estimating-thickness-of-the-inner-dead-layer-of-n-type-hpge-detector
#10
Huynh Dinh Chuong, Tran Thien Thanh, Le Thi Ngoc Trang, Vo Hoang Nguyen, Chau Van Tao
In this study, a procedure to estimate thickness of the inner dead-layer of an n-type coaxial HPGe detector is described. Experimental measurements are carried out with standard point sources: (54)Mn, (57)Co, (60)Co, (88)Y, (109)Cd, (134)Cs, (137)Cs, and (152)Eu at distances of 5 and 10cm from source to detector. Shape and dimensions of a high-purity germanium (HPGe) detector are determined by radiography to characterize the geometry accurately for Monte Carlo simulation. The role of thickness of the inner dead-layer on full energy peak efficiency is illustrated by MCNP5 code, and it is observed that slope coefficient of efficiency curve has a linear relationship with thickness of the dead-layer...
October 2016: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/27546490/utilization-of-134-cs-137-cs-in-the-environment-to-identify-the-reactor-units-that-caused-atmospheric-releases-during-the-fukushima-daiichi-accident
#11
Masamichi Chino, Hiroaki Terada, Haruyasu Nagai, Genki Katata, Satoshi Mikami, Tatsuo Torii, Kimiaki Saito, Yukiyasu Nishizawa
The Fukushima Daiichi nuclear power reactor units that generated large amounts of airborne discharges during the period of March 12-21, 2011 were identified individually by analyzing the combination of measured (134)Cs/(137)Cs depositions on ground surfaces and atmospheric transport and deposition simulations. Because the values of (134)Cs/(137)Cs are different in reactor units owing to fuel burnup differences, the (134)Cs/(137)Cs ratio measured in the environment was used to determine which reactor unit ultimately contaminated a specific area...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27538842/internal-thyroid-doses-to-fukushima-residents-estimation-and-issues-remaining
#12
Eunjoo Kim, Osamu Kurihara, Naoaki Kunishima, Takumaro Momose, Tetsuo Ishikawa, Makoto Akashi
Enormous quantities of radionuclides were released into the environment following the disastrous accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011. It is of great importance to determine the exposure doses received by the populations living in the radiologically affected areas; however, there has been significant difficulty in estimating the internal thyroid dose received through the intake of short-lived radionuclides (mainly, (131)I), because of the lack of early measurements on people...
August 2016: Journal of Radiation Research
https://www.readbyqxmd.com/read/27494655/temporal-variation-of-sedimentation-rates-and-potential-factors-influencing-those-rates-over-the-last-100years-in-bohai-bay-china
#13
Yan Zhang, Xueqiang Lu, Xiaolong Shao, Chen Chen, Xiaojuan Li, Feng Zhao, Gang Li, Eijij Matsumoto
Fourteen sediment cores were collected from Bohai Bay, China, which is close to the fast-developing megacities such as Beijing and Tianjin, and dated using excess Pb-210 and Cs-137. Using the constant rate of supply model (CRS), the temporal variation of sedimentation rates over the last 100years in Bohai Bay was determined, and its main factors influencing sedimentation rates were discussed. The sedimentation rates before 1980 were relatively stable, ranging from 0.26±0.04g/(cm(2)·y) in 1920 to 0.39±0.08g/(cm(2)·y) in 1980...
August 2, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/27489519/dose-distribution-verification-for-gyn-brachytherapy-using-ebt-gafchromic-film-and-tg-43-calculation
#14
Somayeh Gholami, Hamid Reza Mirzaei, Ali Jabbary Arfaee, Ramin Jaberi, Hassan Ali Nedaie, Seied Rabi Mahdavi, Eftekhar Rajab Bolookat, Ali S Meigooni
AIM: Verification of dose distributions for gynecological (GYN) brachytherapy implants using EBT Gafchromic film. BACKGROUND: One major challenge in brachytherapy is to verify the accuracy of dose distributions calculated by a treatment planning system. MATERIALS AND METHODS: A new phantom was designed and fabricated using 90 slabs of 18 cm × 16 cm × 0.2 cm Perspex to accommodate a tandem and Ovoid assembly, which is normally used for GYN brachytherapy treatment...
September 2016: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/27474279/simultaneous-determination-of-radiocesium-135-cs-137-cs-and-plutonium-239-pu-240-pu-isotopes-in-river-suspended-particles-by-icp-ms-ms-and-sf-icp-ms
#15
Liguo Cao, Jian Zheng, Hirofumi Tsukada, Shaoming Pan, Zhongtang Wang, Keiko Tagami, Shigeo Uchida
Due to radioisotope releases in the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, long-term monitoring of radiocesium ((135)Cs and (137)Cs) and Pu isotopes ((239)Pu and (240)Pu) in river suspended particles is necessary to study the transport and fate of these long-lived radioisotopes in the land-ocean system. However, it is expensive and technically difficult to collect samples of suspended particles from river and ocean. Thus, simultaneous determination of multi-radionuclides remains as a challenging topic...
October 1, 2016: Talanta
https://www.readbyqxmd.com/read/27447690/radioactive-contamination-of-arthropods-from-different-trophic-levels-in-hilly-and-mountainous-areas-after-the-fukushima-daiichi-nuclear-power-plant-accident
#16
Sota Tanaka, Kaho Hatakeyama, Sentaro Takahashi, Tarô Adati
In order to understand the influence of the Fukushima Daiichi nuclear power plant accident on the ecosystem in hilly and mountainous areas of Fukushima Prefecture, chronological changes in the levels of radiocesium in arthropod species were investigated. From 2012 to 2014, arthropods from different trophic levels were sampled and the air radiation dose rates at the sampling sites were analyzed. The air radiation dose rates showed a significant and constant reduction over the 2 years at the sampling sites in Fukushima...
November 2016: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/27423074/radiocaesium-contamination-of-wild-boars-in-fukushima-and-surrounding-regions-after-the-fukushima-nuclear-accident
#17
Shoichi Fuma, Yoshihisa Kubota, Sadao Ihara, Hiroyuki Takahashi, Yoshito Watanabe, Tatsuo Aono, Haruhi Soeda, Satoshi Yoshida
Analysis of radioactivity data obtained under the food monitoring campaign in Japan indicates that elevated (134)Cs+(137)Cs activity concentrations in wild boar meat remained constant or slowly decreased in Fukushima and surrounding prefectures from 2011 to 2015. The activity concentrations in some samples are still over the regulatory limit of 100 Bq kg(-1) fresh weight, even in 2015. Activity concentrations of (137)Cs in muscle of wild boars we captured in 2011 were higher than those in kidney, liver, spleen, heart and lung...
November 2016: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/27400653/assessment-of-residual-doses-to-population-after-decontamination-in-fukushima-prefecture
#18
Airi Mori, Shogo Takahara, Azusa Ishizaki, Masashi Iijima, Yukihisa Sanada, Masahiro Munakata
Large quantities of radioactive materials were released into the environment as a result of the Fukushima Daiichi Nuclear Power Station accident. Many inhabitants residing in the affected areas are now exposed to radiation in their daily lives. In an attempt to manage this radiation dose, an additional radiation dose of 1 mSv/y was adopted as a long-term dosimetric target. An activity level reading of 0.23 μSv/h was then determined as a guidance value to achieve the target by implementing decontamination measures...
January 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/27357196/estimated-association-between-dwelling-soil-contamination-and-internal-radiation-contamination-levels-after-the-2011-fukushima-daiichi-nuclear-accident-in-japan
#19
Masaharu Tsubokura, Shuhei Nomura, Kikugoro Sakaihara, Shigeaki Kato, Claire Leppold, Tomoyuki Furutani, Tomohiro Morita, Tomoyoshi Oikawa, Yukio Kanazawa
OBJECTIVES: Measurement of soil contamination levels has been considered a feasible method for dose estimation of internal radiation exposure following the Chernobyl disaster by means of aggregate transfer factors; however, it is still unclear whether the estimation of internal contamination based on soil contamination levels is universally valid or incident specific. METHODS: To address this issue, we evaluated relationships between in vivo and soil cesium-137 (Cs-137) contamination using data on internal contamination levels among Minamisoma (10-40 km north from the Fukushima Daiichi nuclear power plant), Fukushima residents 2-3 years following the disaster, and constructed three models for statistical analysis based on continuous and categorical (equal intervals and quantiles) soil contamination levels...
2016: BMJ Open
https://www.readbyqxmd.com/read/27289189/apparatus-development-for-measurement-of-134-cs-and-137-cs-radioactivity-of-soil-contaminated-by-the-fukushima-daiichi-nuclear-power-plant-accident
#20
Tsuyoshi Kajimoto, Satoru Endo, Kenichi Tanaka, Yasuharu Okashiro, Hiroaki Kai, Syuuji Fujii, Atsushi Mishima, Takahide Matsubara, Shinji Yoshida
We developed an apparatus containing a NaI(Tl) scintillator to measure the (134)Cs and (137)Cs radioactivity of soil contaminated by the Fukushima Daiichi Nuclear Power Plant accident. The unfolding method with the least-squares technique was used to determine the radioactivity. Detector responses for each radionuclide in soil were calculated with EGS5 code for the unfolding method. The radionuclides that were measured were (40)K, (134)Cs, (137)Cs, (208)Tl, (214)Bi, and (228)Ac. The measured spectrum agreed well with the spectrum calculated from the response matrix and measured radioactivities...
September 2016: Applied Radiation and Isotopes
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