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Sample records for mgi arvid kaarma

  1. Kaarma Bold Italic / Tõnu Kaalep

    Index Scriptorium Estoniae

    Kaalep, Tõnu, 1966-

    2000-01-01

    Raamatukujundajast Jüri Kaarmast ja tema loomingust. Kommenteerib abikaasa Eve Kask. J. Kaarma sellest, miks temast sai raamatukujundaja, oma parimatest õpetajatest (E. Kärmas, I. Paul), töömeetodist, loomingust, uue kirjatüübi konstrueerimisest jm

  2. Kaarma Bold Italic / Tõnu Kaalep

    Index Scriptorium Estoniae

    Kaalep, Tõnu, 1966-

    2011-01-01

    Raamatukujundajast Jüri Kaarmast ja tema loomingust. Kommenteerib abikaasa Eve Kask. J. Kaarma sellest, miks temast sai raamatukujundaja, oma parimatest õpetajatest (E. Kärmas, I. Paul), töömeetodist, loomingust, uue kirjatüübi konstrueerimisest jm

  3. Melanie Kaarma moealbum / Juta Kivimäe

    Index Scriptorium Estoniae

    Kivimäe, Juta, 1952-

    2008-01-01

    Näitus "Melanie Kaarma - 85. Tagasivaade moeloomingule" Vabaduse galeriis kuni 5. I 2009. Melanie Kaarma lõpetas 1948. a. Tallinna Riikliku Tarbekunsti Instituudi kostüümikunstnikuna, oli aastatel 1952-1957 aastaväljaannetena ilmunud "Moealbumi" kunstnik ja vastutav toimetaja

  4. Mouse Genome Informatics (MGI)

    Data.gov (United States)

    U.S. Department of Health & Human Services — MGI is the international database resource for the laboratory mouse, providing integrated genetic, genomic, and biological data to facilitate the study of human...

  5. Maksuameti võimatu missioon / Lemmi Kann ; kommenteerinud Lasse Lehis, Rait Kaarma, Taavi Veskimägi

    Index Scriptorium Estoniae

    Kann, Lemmi

    2009-01-01

    Väljavõte artiklist: Maksude optimeerijad tõmmatakse liistule / Lemmi Kann (aripaev.ee, 17.03.2009). Kommenteerivad Eesti Maksumaksjate Liidu juhatuse esimees Lasse Lehis, Alvin, Rödl & Partner Advokaadibüroo OÜ advokaat Rait Kaarma ja Riigikogu liige Taavi Veskimägi

  6. MouseMine: a new data warehouse for MGI.

    Science.gov (United States)

    Motenko, H; Neuhauser, S B; O'Keefe, M; Richardson, J E

    2015-08-01

    MouseMine (www.mousemine.org) is a new data warehouse for accessing mouse data from Mouse Genome Informatics (MGI). Based on the InterMine software framework, MouseMine supports powerful query, reporting, and analysis capabilities, the ability to save and combine results from different queries, easy integration into larger workflows, and a comprehensive Web Services layer. Through MouseMine, users can access a significant portion of MGI data in new and useful ways. Importantly, MouseMine is also a member of a growing community of online data resources based on InterMine, including those established by other model organism databases. Adopting common interfaces and collaborating on data representation standards are critical to fostering cross-species data analysis. This paper presents a general introduction to MouseMine, presents examples of its use, and discusses the potential for further integration into the MGI interface.

  7. Lines of MgI Detected in Solar Prominences

    Czech Academy of Sciences Publication Activity Database

    Heinzel, Petr; Kupryakov, Yu. A.; Schwartz, P.

    2016-01-01

    Roč. 40, č. 1 (2016), s. 87-91 ISSN 1845-8319. [Hvar Astrophysical Colloquium /14./. Hvar, 26.09.2016-30.09.2016] Institutional support: RVO:67985815 Keywords : prominences * limb-flare * MgI emession Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  8. Multi-MGy Radiation Hardened Camera for Nuclear Facilities

    International Nuclear Information System (INIS)

    Girard, Sylvain; Boukenter, Aziz; Ouerdane, Youcef; Goiffon, Vincent; Corbiere, Franck; Rolando, Sebastien; Molina, Romain; Estribeau, Magali; Avon, Barbara; Magnan, Pierre; Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Raine, Melanie

    2015-01-01

    There is an increasing interest in developing cameras for surveillance systems to monitor nuclear facilities or nuclear waste storages. Particularly, for today's and the next generation of nuclear facilities increasing safety requirements consecutive to Fukushima Daiichi's disaster have to be considered. For some applications, radiation tolerance needs to overcome doses in the MGy(SiO 2 ) range whereas the most tolerant commercial or prototypes products based on solid state image sensors withstand doses up to few kGy. The objective of this work is to present the radiation hardening strategy developed by our research groups to enhance the tolerance to ionizing radiations of the various subparts of these imaging systems by working simultaneously at the component and system design levels. Developing radiation-hardened camera implies to combine several radiation-hardening strategies. In our case, we decided not to use the simplest one, the shielding approach. This approach is efficient but limits the camera miniaturization and is not compatible with its future integration in remote-handling or robotic systems. Then, the hardening-by-component strategy appears mandatory to avoid the failure of one of the camera subparts at doses lower than the MGy. Concerning the image sensor itself, the used technology is a CMOS Image Sensor (CIS) designed by ISAE team with custom pixel designs used to mitigate the total ionizing dose (TID) effects that occur well below the MGy range in classical image sensors (e.g. Charge Coupled Devices (CCD), Charge Injection Devices (CID) and classical Active Pixel Sensors (APS)), such as the complete loss of functionality, the dark current increase and the gain drop. We'll present at the conference a comparative study between these radiation-hardened pixel radiation responses with respect to conventional ones, demonstrating the efficiency of the choices made. The targeted strategy to develop the complete radiation hard camera

  9. Multi-MGy Radiation Hardened Camera for Nuclear Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Sylvain; Boukenter, Aziz; Ouerdane, Youcef [Universite de Saint-Etienne, Lab. Hubert Curien, UMR-CNRS 5516, F-42000 Saint-Etienne (France); Goiffon, Vincent; Corbiere, Franck; Rolando, Sebastien; Molina, Romain; Estribeau, Magali; Avon, Barbara; Magnan, Pierre [ISAE, Universite de Toulouse, F-31055 Toulouse (France); Paillet, Philippe; Duhamel, Olivier; Gaillardin, Marc; Raine, Melanie [CEA, DAM, DIF, F-91297 Arpajon (France)

    2015-07-01

    There is an increasing interest in developing cameras for surveillance systems to monitor nuclear facilities or nuclear waste storages. Particularly, for today's and the next generation of nuclear facilities increasing safety requirements consecutive to Fukushima Daiichi's disaster have to be considered. For some applications, radiation tolerance needs to overcome doses in the MGy(SiO{sub 2}) range whereas the most tolerant commercial or prototypes products based on solid state image sensors withstand doses up to few kGy. The objective of this work is to present the radiation hardening strategy developed by our research groups to enhance the tolerance to ionizing radiations of the various subparts of these imaging systems by working simultaneously at the component and system design levels. Developing radiation-hardened camera implies to combine several radiation-hardening strategies. In our case, we decided not to use the simplest one, the shielding approach. This approach is efficient but limits the camera miniaturization and is not compatible with its future integration in remote-handling or robotic systems. Then, the hardening-by-component strategy appears mandatory to avoid the failure of one of the camera subparts at doses lower than the MGy. Concerning the image sensor itself, the used technology is a CMOS Image Sensor (CIS) designed by ISAE team with custom pixel designs used to mitigate the total ionizing dose (TID) effects that occur well below the MGy range in classical image sensors (e.g. Charge Coupled Devices (CCD), Charge Injection Devices (CID) and classical Active Pixel Sensors (APS)), such as the complete loss of functionality, the dark current increase and the gain drop. We'll present at the conference a comparative study between these radiation-hardened pixel radiation responses with respect to conventional ones, demonstrating the efficiency of the choices made. The targeted strategy to develop the complete radiation hard camera

  10. Fuel retention and recovery in natural and MGI disruptions on KSTAR

    International Nuclear Information System (INIS)

    Yu, Y.W.; Hong, S.H.; Yoon, S.W.; Kim, K.P.; Kim, W.C.; Seo, D.C.

    2013-01-01

    Fuel retention and recovery are studied during natural and Massive Gas Injection (MGI) induced disruptions in KSTAR with full graphite wall. The amount of released particles in natural disruptions in 15 s after the discharge is ∼5–10 times higher than that of non-disruption shots, but the difference is only ∼ 2 MGI induced disruptions depends on magnetic field (B t ) and MGI amount. The MGI disruption under a low B t and a medium MGI amount shows shorter thermal quench (TQ) and current quench (CQ), thereby higher fuel recovery. High B t plasma requires higher MGI amount for both disruption mitigation and fuel recovery. A high recovery of 4.2 × 10 22 D (∼0.78 monolayers) is obtained by MGI disruption in KSTAR 2011

  11. Mouse Genome Informatics (MGI) Resource: Genetic, Genomic, and Biological Knowledgebase for the Laboratory Mouse.

    Science.gov (United States)

    Eppig, Janan T

    2017-07-01

    The Mouse Genome Informatics (MGI) Resource supports basic, translational, and computational research by providing high-quality, integrated data on the genetics, genomics, and biology of the laboratory mouse. MGI serves a strategic role for the scientific community in facilitating biomedical, experimental, and computational studies investigating the genetics and processes of diseases and enabling the development and testing of new disease models and therapeutic interventions. This review describes the nexus of the body of growing genetic and biological data and the advances in computer technology in the late 1980s, including the World Wide Web, that together launched the beginnings of MGI. MGI develops and maintains a gold-standard resource that reflects the current state of knowledge, provides semantic and contextual data integration that fosters hypothesis testing, continually develops new and improved tools for searching and analysis, and partners with the scientific community to assure research data needs are met. Here we describe one slice of MGI relating to the development of community-wide large-scale mutagenesis and phenotyping projects and introduce ways to access and use these MGI data. References and links to additional MGI aspects are provided. © The Author 2017. Published by Oxford University Press.

  12. The radiation asymmetry in MGI rapid shutdown on J-TEXT tokamak

    Science.gov (United States)

    Tong, Ruihai; Chen, Zhongyong; Huang, Duwei; Cheng, Zhifeng; Zhang, Xiaolong; Zhuang, Ge; J-TEXT Team

    2017-10-01

    Disruptions, the sudden termination of tokamak fusion plasmas by instabilities, have the potential to cause severe material wall damage to large tokamaks like ITER. The mitigation of disruption damage is an essential part of any fusion reactor system. Massive gas injection (MGI) rapid shutdown is a technique in which large amounts of noble gas are injected into the plasma in order to safely radiate the plasma energy evenly over the entire plasma-facing first wall. However, the radiated energy during the thermal quench (TQ) in massive gas injection (MGI) induced disruptions is found toroidal asymmetric, and the degrees of asymmetry correlate with the gas penetration and MGI induced magnetohydrodynamics (MHD) activities. A toroidal and poloidal array of ultraviolet photodiodes (AXUV) has been developed to investigate the radiation asymmetry on J-TEXT tokamak. Together with the upgraded mirnov probe arrays, the relation between MGI triggered MHD activities with radiation asymmetry is studied.

  13. Mouse Genome Informatics (MGI) Is the International Resource for Information on the Laboratory Mouse.

    Science.gov (United States)

    Law, MeiYee; Shaw, David R

    2018-01-01

    Mouse Genome Informatics (MGI, http://www.informatics.jax.org/ ) web resources provide free access to meticulously curated information about the laboratory mouse. MGI's primary goal is to help researchers investigate the genetic foundations of human diseases by translating information from mouse phenotypes and disease models studies to human systems. MGI provides comprehensive phenotypes for over 50,000 mutant alleles in mice and provides experimental model descriptions for over 1500 human diseases. Curated data from scientific publications are integrated with those from high-throughput phenotyping and gene expression centers. Data are standardized using defined, hierarchical vocabularies such as the Mammalian Phenotype (MP) Ontology, Mouse Developmental Anatomy and the Gene Ontologies (GO). This chapter introduces you to Gene and Allele Detail pages and provides step-by-step instructions for simple searches and those that take advantage of the breadth of MGI data integration.

  14. Microstructural evolution during dry wear test in magnesium and Mg-Y alloy

    Energy Technology Data Exchange (ETDEWEB)

    Somekawa, Hidetoshi, E-mail: SOMEKAWA.Hidetoshi@nims.go.jp [Research Center for Strategic Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Maeda, Shunsuke; Hirayama, Tomoko; Matsuoka, Takashi [Department of Mechanical Engineering, Doshisha University, 1-3 Miyakodani, Tatara, Kyotanabe 610-0321 (Japan); Inoue, Tadanobu [Research Center for Strategic Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047 (Japan); Mukai, Toshiji [Department of Mechanical Engineering, Kobe University, 1-1 Rokkodai, Kobe, 657-8501 (Japan)

    2013-01-20

    The friction and wear properties of pure magnesium and the Mg-Y alloy were investigated using the pin-on-disk configuration. The friction and wear resistance of the Mg-Y alloy was superior to those of pure magnesium. The wear mechanism was abrasion under all the conditions. The deformed microstructural evolutions near the surface region were observed by transmission electron microscopy and electron backscatter diffraction. The stress and strain states were also evaluated by finite element analysis (FEA). The deformed microstructures of both alloys consisted of the {l_brace}10-12{r_brace} twinning formation and the FEA results showed the occurrence of plastic deformation even at the beginning of the test. The formation of low angle grain boundaries was also confirmed with an increase in the applied load in the Mg-Y alloy. On the other hand, grain refinement due to dynamic recrystallization was observed in pure magnesium as the wear test progressed. The different microstructures resulted from difference in the surface temperature during the wear test, which was estimated to be around 393 K and 363 K for pure magnesium and the Mg-Y alloy, respectively. The high increment temperature in the fine-grained alloys brought about the occurrence of grain boundary sliding, i.e., material softening, which led to a decrease in the friction and wear properties. The present results indicated that one of the methods for enhancing the friction and wear properties is to increase the dynamic recrystallization temperature.

  15. HUBUNGAN CITRA MERK BUS (MGI DENGAN KEPUASAN KONSUMEN PADA TRAYEK BANDUNG-SUKABUMI

    Directory of Open Access Journals (Sweden)

    Ulfa Chairunnisa

    2018-02-01

    Full Text Available This research aims to study correlation between brand image and customer satisfaction. Quantitative design using correlational method involved 350 MGI bus customer in Bandung-Sukabumi route. Instruments used are Brand Image Inventory (37 item and Customer Satisfaction Index (37 item. Cooeficient  correlation resulted is 0.684 which means that there is positive correlation between brand image and customer satisfction. High brand image correlated with high customer satisfaction while low brand image correlated with low customer satisfaction.

  16. HUBUNGAN CITRA MERK BUS (MGI) DENGAN KEPUASAN KONSUMEN PADA TRAYEK BANDUNG-SUKABUMI

    OpenAIRE

    Ulfa Chairunnisa

    2018-01-01

    This research aims to study correlation between brand image and customer satisfaction. Quantitative design using correlational method involved 350 MGI bus customer in Bandung-Sukabumi route. Instruments used are Brand Image Inventory (37 item) and Customer Satisfaction Index (37 item). Cooeficient  correlation resulted is 0.684 which means that there is positive correlation between brand image and customer satisfction. High brand image correlated with high customer satisfaction while low bran...

  17. The influence of yttrium (Y) on the corrosion of Mg-Y binary alloys

    International Nuclear Information System (INIS)

    Liu Ming; Schmutz, Patrik; Uggowitzer, Peter J.; Song Guangling; Atrens, Andrej

    2010-01-01

    Research highlights: → The Y-intermetallic can accelerate corrosion and Y can increase the protectiveness of the surface layer. → In 0.1 M NaCl, the corrosion rate of Mg-Y alloys increased with increasing Y due to the Y intermetallic. → In 0.1 M NaCl, there was filiform corrosion. → In 0.1 M Na 2 SO 4 , the corrosion rate of Mg-Y alloys decreased with increasing Y in the range 3-7%Y. → Hydrogen evolution was observed from particular parts of the alloy surface. - Abstract: Corrosion of Mg-Y alloys was studied using electrochemical evaluations, immersion tests and direct observations. There were two important effects. In 0.1 M NaCl, the corrosion rate increased with increasing Y content due to increasing amounts of the Y-containing intermetallic. In 0.1 M Na 2 SO 4 , the corrosion rate decreased with increasing Y content above 3%, attributed to a more protective surface film, despite the intermetallic. The corrosion rate evaluated by electrochemical impedance spectroscopy was somewhat smaller than that evaluated from H evolution as expected from the Mg corrosion mechanism. A mechanism is proposed for filiform corrosion. Direct in situ corrosion observations revealed that a predominant feature was hydrogen evolution from particular parts of the alloy surface.

  18. Determination of gold and silver in geological standard samples MGI by instrument neutron activation analysis

    International Nuclear Information System (INIS)

    Lu Huijiuan; Zhou; Yunlu

    1987-01-01

    Gold and silver in geological standard samples MGI were determined by instrument neutron activation analysis. The various interferences of nuclides were considered. Corrected factors of the geometry in different positions have been determined. Using the geological standard sample MGM and radiochemical separation neutron activation method as reference, the reliability of this method is proved. Gold content in samples is 0.4-0.009 g/t, silver content is 9-0.3 g/t. Standard deviation is less than 3.5%, the precision of the measurement is 4.8-11.6%

  19. Effects of spin-orbit coupling on laser cooling of BeI and MgI

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Mingjie, E-mail: wanmingjie1983@sina.com; Huang, Duohui; Shao, Juxiang; Li, Yuanyuan [Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007 (China); Yu, You [College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu 610225 (China); Li, Song [College of Physical Science and Technology, Yangtze University, Jingzhou 434023 (China)

    2015-10-28

    We present the ab initio study of spin-orbit coupling effects on laser cooling of BeI and MgI molecules. Potential energy curves for the X{sup 2}Σ{sup +}{sub 1/2}, A{sup 2}Π{sub 1/2,3/2}, and 2{sup 2}Π{sub 3/2,1/2} states are calculated using multi-reference configuration interaction method plus Davidson corrections. Spectroscopic parameters of BeI and MgI are in excellent agreement with available experimental and theoretical values. The A{sup 2}Π{sub 3/2} state of MgI is a repulsive state. It is an unsuitable scheme for the A{sup 2}Π{sub 3/2}(υ′)← X{sup 2}Σ{sup +}{sub 1/2} (υ″) transition for laser cooling of MgI. Highly diagonally distributed Franck-Condon factors f{sub 00} for the A{sup 2}Π{sub 1/2,3/2} (υ′ = 0) ← X{sup 2}Σ{sup +}{sub 1/2} (υ″ = 0) transitions and suitable radiative lifetimes τ for the A{sup 2}Π{sub 1/2,3/2} (υ′ = 0) of BeI and MgI are obtained. Three laser wavelength drives are required for the A{sup 2}Π{sub 1/2,3/2}(υ′)←X{sup 2}Σ{sup +}{sub 1/2} (υ″) transitions of BeI and MgI. The proposed cooling wavelengths of BeI and MgI are both in the violet region. The results imply the feasibility of laser cooling of BeI and MgI, and that laser cooling of BeI is more possible.

  20. Investigations on MGy ionizing dose effects in thin oxides of micro-electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Gaillardin, M.; Paillet, P.; Raine, M.; Martinez, M.; Marcandella, C.; Duhamel, O.; Richard, N.; Leray, J.L. [CEA, DAM, DIF, F-91297 Arpajon (France); Goiffon, V.; Corbiere, F.; Rolando, S.; Molina, R.; Magnan, P. [ISAE, Universite de Toulouse, 10 avenue Edouard Belin, BP 54032, 31055 Toulouse Cedex 4 (France); Girard, S.; Ouerdane, Y.; Boukenter, A. [Universite de Saint-Etienne, Laboratoire H. Curien, UMR-5516, 42000, Saint-Etienne (France)

    2015-07-01

    Total ionizing dose (TID) effects have been studied for a long time in micro-electronic components designed to operate in natural and artificial environments. In most cases, TID induces both charge trapping in the bulk of irradiated oxides and the buildup of interface traps located at semiconductor/dielectric interfaces. Such effects result from basic mechanisms driven by both the shape of the electric field which stands into the oxide and by fabrication process parameters inducing pre-existing traps in the oxide's bulk. From the pioneering studies based on 'thick' oxide technologies to the most recent ones dedicated to innovative technologies, most studies concluded that the impact of total ionizing dose effects reduces with the oxide thinning. This is specifically the case for the gate-oxide of Metal-Oxide-Semiconductor Field Effect Transistors (MOSFET) for which it is generally considered that TID is not a major issue anymore at kGy dose ranges. TID effects are now mainly due to charge trapping in the field oxides such as Shallow Trench Isolation. This creates either parasitic conduction paths or Radiation-Induced Narrow Channel Effects (RINCE). Static current-voltage (I-V) electrical characteristics are then modified through a significant increase of the off-current of NMOS transistors or by shifting the whole I-V curves (of both NMOS and PMOS transistors). Based on these assumptions, no significant shift of I-V curves should be observed in modern bulk CMOS technologies. However, such phenomenon may not be directly extrapolated to higher TID ranges, typically of several MGy for which only few data are available in the literature. This paper presents evidences of large threshold voltage shifts measured at MGy dose levels despite the fact that transistors are designed in a submicron bulk technology which features a 7-nm thin gate-oxide on GO2 transistors dedicated to mixed analog/digital integrated circuits. Such electrical shifts are encountered

  1. Investigations on MGy ionizing dose effects in thin oxides of micro-electronic devices

    International Nuclear Information System (INIS)

    Gaillardin, M.; Paillet, P.; Raine, M.; Martinez, M.; Marcandella, C.; Duhamel, O.; Richard, N.; Leray, J.L.; Goiffon, V.; Corbiere, F.; Rolando, S.; Molina, R.; Magnan, P.; Girard, S.; Ouerdane, Y.; Boukenter, A.

    2015-01-01

    Total ionizing dose (TID) effects have been studied for a long time in micro-electronic components designed to operate in natural and artificial environments. In most cases, TID induces both charge trapping in the bulk of irradiated oxides and the buildup of interface traps located at semiconductor/dielectric interfaces. Such effects result from basic mechanisms driven by both the shape of the electric field which stands into the oxide and by fabrication process parameters inducing pre-existing traps in the oxide's bulk. From the pioneering studies based on 'thick' oxide technologies to the most recent ones dedicated to innovative technologies, most studies concluded that the impact of total ionizing dose effects reduces with the oxide thinning. This is specifically the case for the gate-oxide of Metal-Oxide-Semiconductor Field Effect Transistors (MOSFET) for which it is generally considered that TID is not a major issue anymore at kGy dose ranges. TID effects are now mainly due to charge trapping in the field oxides such as Shallow Trench Isolation. This creates either parasitic conduction paths or Radiation-Induced Narrow Channel Effects (RINCE). Static current-voltage (I-V) electrical characteristics are then modified through a significant increase of the off-current of NMOS transistors or by shifting the whole I-V curves (of both NMOS and PMOS transistors). Based on these assumptions, no significant shift of I-V curves should be observed in modern bulk CMOS technologies. However, such phenomenon may not be directly extrapolated to higher TID ranges, typically of several MGy for which only few data are available in the literature. This paper presents evidences of large threshold voltage shifts measured at MGy dose levels despite the fact that transistors are designed in a submicron bulk technology which features a 7-nm thin gate-oxide on GO2 transistors dedicated to mixed analog/digital integrated circuits. Such electrical shifts are encountered

  2. A MGy radiation-hardened sensor instrumentation link for nuclear reactor monitoring and remote handling

    Energy Technology Data Exchange (ETDEWEB)

    Verbeeck, Jens; Cao, Ying [KU Leuven - KUL, Div. LRD-MAGyICS, Kasteelpark Arenberg 10, 3001 Heverlee (Belgium); Van Uffelen, Marco; Mont Casellas, Laura; Damiani, Carlo; Morales, Emilio Ruiz; Santana, Roberto Ranz [Fusion for Energy - F4E, c/Josep,n deg. 2, Torres Diagonal Litoral, Ed. B3, 08019 Barcelona (Spain); Meek, Richard; Haist, Bernhard [Oxford Technologies Ltd. OTL, 7 Nuffield Way, Abingdon OX14 1RL (United Kingdom); De Cock, Wouter; Vermeeren, Ludo [SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Steyaert, Michiel [KU Leuven, ESAT-MICAS, KasteelparkArenberg 10, 3001 Heverlee (Belgium); Leroux, Paul [KU Leuven, ESAT-MICAS, KasteelparkArenberg 10, 3001 Heverlee (Belgium)

    2015-07-01

    Decommissioning, dismantling and remote handling applications in nuclear facilities all require robotic solutions that are able to survive in radiation environments. Recently raised safety, radiation hardness and cost efficiency demands from both the nuclear regulatory and the society impose severe challenges in traditional methods. For example, in case of the dismantling of the Fukushima sites, solutions that survive accumulated doses higher than 1 MGy are mandatory. To allow remote operation of these tools in nuclear environments, electronics were used to be shielded with several centimeters of lead or even completely banned in these solutions. However, shielding electronics always leads to bulky and heavy solutions, which reduces the flexibility of robotic tools. It also requires longer repair time and produces extra waste further in a dismantling or decommissioning cycle. In addition, often in current reactor designs, due to size restrictions and the need to inspect very tight areas there are limitations to the use of shielding. A MGy radiation-hardened sensor instrumentation link developed by MAGyICS provides a solution to build a flexible, easy removable and small I and C module with MGy radiation tolerance without any shielding. Hereby it removes all these pains to implement electronics in robotic tools. The demonstrated solution in this poster is developed for ITER Remote Handling equipments operating in high radiation environments (>1 MGy) in and around the Tokamak. In order to obtain adequately accurate instrumentation and control information, as well as to ease the umbilical management, there is a need of front-end electronics that will have to be located close to those actuators and sensors on the remote handling tool. In particular, for diverter remote handling, it is estimated that these components will face gamma radiation up to 300 Gy/h (in-vessel) and a total dose of 1 MGy. The radiation-hardened sensor instrumentation link presented here, consists

  3. Study on the early surface films formed on Mg-Y molten alloy in different atmospheres

    Directory of Open Access Journals (Sweden)

    A.R. Mirak

    2015-09-01

    Full Text Available In the present study, the non-isothermal early stages of surface oxidation of liquid Mg-1%Y alloy during casting were studied under UPH argon, dry air, and air mixed with protective fluorine-bearing gases. The chemistry and morphology of the surface films were characterized by SEM and EDX analyses. The results indicate a layer of smooth and tightly coherent oxidation film composed of MgO and Y2O3 formed on the molten Mg-Y alloy surface with 40–60 nm thickness under dry air. A dendritic/cellular microstructure is clearly visible with Y-rich second phases gathered in surface of the melt and precipitated along the grain/cell boundaries under all gas conditions. Under fluorine-bearing gas mixtures, the surface film was a mixed oxide and fluoride and more even; a flat and folded morphology can be seen under SF6 with oxide as dominated phase and under 1, 1, 1, 2-tetra-fluoroethane, a smooth and compact surface film uniformly covering the inner surface of the bubble with equal oxide and fluoride thickness, which results in a film without any major defects. MgF2 phase appears to be the key characteristic of a good protective film.

  4. In situ electrochemical XRD study of (de)hydrogenation of MgyTi100-y thin films

    NARCIS (Netherlands)

    Vermeulen, P.; Wondergem, H.J.; Graat, P.C.J.; Borsa, D.M.; Schreuders, H.; Dam, B.; Griessen, R.; Notten, P.H.L.

    2008-01-01

    X-ray diffraction and electrochemical (de)hydrogenation were performed in situ to monitor the symmetry of the unit cells of MgyTi100-y thin film alloys (with 70 to 90 at.% Mg) along the pressure composition isotherms at room temperature. The diffraction patterns show that the crystal structures of

  5. Simulation of MGI efficiency for plasma energy conversion into Ar radiation in JET and implications for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Pestchanyi, Serguei, E-mail: serguei.pestchanyi@kit.edu [Association EURATOM-KIT, Karlsruhe (Germany); Koslowski, Rudi; Reux, Cedric [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Lehnen, Michael [Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2015-10-15

    Highlights: • We simulated disruption mitigation using massive gas injection with the TOKES code. • Cross-reference analysis of JET experiments on MGI and their simulations have been done. • The analysis allows suggesting the mechanism for saturation of radiated energy fraction at 70–80%. • Rough extrapolation of the result on ITER conditions has been done. - Abstract: Effectiveness of massive gas injection (MGI) for mitigation of disruptive wall damage has been investigated. Cross-reference analysis of the available JET experiments on MGI and their simulations with the TOKES code allow suggesting that in JET conditions one can convert into radiation the electron thermal energy and the plasma current energy, but the ion thermal energy does not convert into radiation because of very ineffective excitation of injected noble gas (NG) ions by D ions and long equipartition time between D ions and electrons. The model assumes rather high electron temperature during current quench (CQ), which contradicts with its time duration. Rough extrapolation of the result on ITER conditions shows that one can expect irradiation of total plasma energy if CQ duration in ITER is not shorter as in JET.

  6. Iodide-conducting polymer electrolytes based on poly-ethylene glycol and MgI2: Synthesis and structural characterization

    International Nuclear Information System (INIS)

    Vittadello, Michele; Waxman, David I.; Sideris, Paul J.; Gan Zhehong; Vezzù, Keti; Negro, Enrico; Safari, Ahmad; Greenbaum, Steve G.; Di Noto, Vito

    2011-01-01

    A major obstacle for a viable technological development of dye sensitized solar cells (DSSCs) is still the synthesis of a high performance iodide-conducting polymer electrolyte. Here we present a series of eight electrolytic complexes with formula PEG1000/(MgI 2 ) x (I 2 ) y (0.0038 ≤ x ≤ 0.5801, 0 ≤ y ≤ 0.0636). The synthesis involves the preparation of a disordered form of MgI 2 by a metallorganic route, which enables us to dissolve high amounts of salt in the chosen polymer host. The thermal analysis of the resulting polymer electrolytes was performed using modulated differential scanning calorimetry measurements. Vibrational studies were carried out using medium FT-IR, far FT-IR and FT-Raman. The variation of the CO and OH stretching modes in the medium infrared, as a function of the mole-to-mole ratio n Mg /n O , was investigated by Gaussian decomposition to provide insight into the polymer–polymer and salt–polymer interactions in these materials. The FT-Raman spectra confirmed and complemented the vibrational assignment. The conductivity study of these systems was performed by electrical spectroscopy in the frequency interval 10 mHz–10 MHz. The direct current conductivity (σ DC ) profiles versus the reciprocal temperature exhibited a Vögel-Tamman-Fülcher (VTF) behavior. The best σ DC at 50 °C was 5 × 10 −5 S cm −1 . The overall results indicate the presence of bivalent, monovalent and neutral species, Mg 2+ , [MgI] + and MgI 2 , respectively, which participate in the conduction process. These results are consistent with what was previously observed in PEG400-based systems doped with δ-MgCl 2 . The presence of at least one Mg site containing a distribution in parameters was observed using 25 Mg solid state magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The site has been assigned to a Mg complex involving the coordination by oxygen atoms of the polymer backbone.

  7. A > 4 MGy radiation tolerant 8 THzOhm transimpedance amplifier with 50 dB dynamic range

    International Nuclear Information System (INIS)

    Verbeeck, J; Steyaert, M; Leroux, P

    2013-01-01

    A 130 nm Transimpedance Amplifier has been developed with a 255 MHz bandwidth, 90 dBΩ transimpedance gain and a dynamic input range of 1:325 or 50 dB for a photo-diode capacitance of 0.75 pF. The equivalent integrated input noise is 160 nA - 25°C. The gain of the voltage amplifier, used in the transimpedance amplifier (TIA), degrades less than 3% over a temperature range from -40 °C up to 125 °C. The TIA and attenuator exhibit a radiation tolerance larger than 4 MGy, as evidenced by radiation assessment.

  8. Immuno-enhancement in tumor-bearing mice induced by whole body X-irradiation with 75 mGy

    International Nuclear Information System (INIS)

    Zhang Ying; Li Xiuyi; Gong Shouliang; Liu Shuzheng

    2000-01-01

    Objective: In present study the authors observed the effect of whole body irradiation (WBI) with 75 mGy X-rays on the immune function of tumor-bearing mice. Methods: Lewis lung carcinoma cells were implanted into the right thigh muscle of C57BL/6J mice. Ten days after tumor implantation, the tumor-bearing mice were administrated with 75 mGy X-rays WBI, then the mice were sacrificed 18 h after irradiation to detect the immune parameters including the spontaneous proliferation of thymocytes, the proliferative response of splenocytes to ConA and LPS, the cytotoxic activities of specific cytotoxic lymphocytes (CTL) and natural killer cells (NK), as well as lymphokine activated killer cells (LAK) in spleen. The methods the authors used were 3 H-TdR incorporation or release assay. Results: the immune parameters of exposed tumor-bearing mice were much higher than those of sham-irradiated tumor-bearing mice (P<0.01). Conclusion: These results suggested that low dose radiation (LDR) could enhance the immune function of tumor-bearing mice, which might be of practical significance in the prevention and therapy of cancer

  9. Design of a MGy radiation tolerant resolver-to-digital convertor IC for remotely operated maintenance in harsh environments

    Energy Technology Data Exchange (ETDEWEB)

    Leroux, Paul, E-mail: paul.leroux@kuleuven.be [KU Leuven, Dept. of Electrical Engineering (ESAT), AdvISe, Kleinhoefstraat 4, 2440 Geel (Belgium); Van Koeckhoven, Wesley; Verbeeck, Jens [KU Leuven, Dept. of Electrical Engineering (ESAT), AdvISe, Kleinhoefstraat 4, 2440 Geel (Belgium); Van Uffelen, Marco; Esqué, Salvador; Ranz, Roberto; Damiani, Carlo [Fusion for Energy, Torres Diagonal Litoral B3, Josep Pla 2, 08019 Barcelona (Spain); Hamilton, David [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance (France)

    2014-10-15

    During future ITER maintenance operations, sensors and their embarked electronics will be exposed to a hostile and radioactive environment. This paper presents the design of a MGy radiation tolerant 16 bit resolver-to-digital converter (RDC) in 130 nm CMOS technology. The RDC features a Type II digital tracking loop, able to track resolvers with speeds up to 300 rps, and excitation frequencies up to 4 kHz. The RDC uses two integrated ΔΣ-analog-to-digital converters (ADCs) to digitize the resolver outputs. The 16 bit, 10 kHz ADCs utilize a correlated double sampling technique to remove radiation induced offset and 1/f-noise. The front-end features a static angular resolution of 16 bits (4.2 arcsec{sub rms}) and a resolution of 10 bits (6 arcmin{sub rms}) at a rotor speed of 100 rps. The circuit has a simulated radiation tolerance exceeding 1 MGy. It has the ability to operate under temperatures up to 125 °C, and to allow multiplexing with signals from other conventional sensors for compact, robust read-out architectures.

  10. Synthesis and characterization of BaxMgyAl2O4: Eu,Dy nanophosphors prepared using solution-combustion method

    CSIR Research Space (South Africa)

    Kebede, MA

    2011-07-01

    Full Text Available Europium-doped barium magnesium aluminate (BaxMgyAl2O4:Eu) phosphors were obtained at low temperature using the solution-combustion of corresponding metal nitrate-urea solution mixtures. The particle sizes, morphology, structural and luminescent...

  11. Design and assessment of a 6 ps-resolution time-to-digital converter with 5 MGy gamma-dose tolerance for nuclear instrumentation

    International Nuclear Information System (INIS)

    Cao, Y.; Leroux, P.; De Cock, W.; Steyaert, M.

    2011-01-01

    Time-to-Digital Converters (TDCs) are key building blocks in time-based mixed-signal systems, used for the digitization of analog signals in time domain. A short survey on state-of-the-art TDCs is given. In order to realize a TDC with picosecond time resolution as well as multi MGy gamma-dose radiation tolerance, a novel multi-stage noise-shaping (MASH) delta-sigma (ΔΣ) TDC structure is proposed. The converter, implemented in 0.13 μm, achieves a time resolution of 5.6 ps and an ENOB of 11 bits, when the over sampling ratio (OSR) is 250. The TDC core consumes only 1.7 mW, and occupies an area of 0.11 mm 2 . Owing to the usage of circuit level radiation hardened-by-design techniques, such as passive RC oscillators and constant-g m biasing, the TDC exhibits enhanced radiation tolerance. At a low dose rate of 1.2 kGy/h, the frequency of the counting clock in the TDC remains constant up to at least 160 kGy. Even after a total dose of 3.4 MGy at a high dose rate of 30 kGy/h, the TDC still achieves a time resolution of 10.5 ps with an OSR of 250. (authors)

  12. Design and assessment of a 6 ps-resolution time-to-digital converter with 5 MGy gamma-dose tolerance for nuclear instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Y. [ESAT-MICAS Div., Katholieke Universiteit Leuven, B-3001 Heverlee (Belgium); SCK.CEN, Belgian Nuclear Research Centre, B-2400 Mol (Belgium); Leroux, P. [ESAT-MICAS Div., Katholieke Universiteit Leuven, B-3001 Heverlee (Belgium); ICT-RELIC Div., Katholieke Hogeschool Kempen, B-2440 Geel (Belgium); De Cock, W. [SCK.CEN, Belgian Nuclear Research Centre, B-2400 Mol (Belgium); Steyaert, M. [ESAT-MICAS Div., Katholieke Universiteit Leuven, B-3001 Heverlee (Belgium)

    2011-07-01

    Time-to-Digital Converters (TDCs) are key building blocks in time-based mixed-signal systems, used for the digitization of analog signals in time domain. A short survey on state-of-the-art TDCs is given. In order to realize a TDC with picosecond time resolution as well as multi MGy gamma-dose radiation tolerance, a novel multi-stage noise-shaping (MASH) delta-sigma ({Delta}{Sigma}) TDC structure is proposed. The converter, implemented in 0.13 {mu}m, achieves a time resolution of 5.6 ps and an ENOB of 11 bits, when the over sampling ratio (OSR) is 250. The TDC core consumes only 1.7 mW, and occupies an area of 0.11 mm{sup 2}. Owing to the usage of circuit level radiation hardened-by-design techniques, such as passive RC oscillators and constant-g{sub m} biasing, the TDC exhibits enhanced radiation tolerance. At a low dose rate of 1.2 kGy/h, the frequency of the counting clock in the TDC remains constant up to at least 160 kGy. Even after a total dose of 3.4 MGy at a high dose rate of 30 kGy/h, the TDC still achieves a time resolution of 10.5 ps with an OSR of 250. (authors)

  13. Total body 100-mGy X-irradiation does not induce Alzheimer's disease-like pathogenesis or memory impairment in mice

    International Nuclear Information System (INIS)

    Wang, Bing; Tanaka, Kaoru; Ji, Bin

    2014-01-01

    The cause and progression of Alzheimer's disease (AD) are poorly understood. Possible cognitive and behavioral consequences induced by low-dose radiation are important because humans are exposed to ionizing radiation from various sources. Early transcriptional response in murine brain to low-dose X-rays (100 mGy) has been reported, suggesting alterations of molecular networks and pathways associated with cognitive functions, advanced aging and AD. To investigate acute and late transcriptional, pathological and cognitive consequences of low-dose radiation, we applied an acute dose of 100-mGy total body irradiation (TBI) with X-rays to C57BL/6J Jms mice. We collected hippocampi and analyzed expression of 84 AD-related genes. Mouse learning ability and memory were assessed with the Morris water maze test. We performed in vivo PET scans with 11 C-PIB, a radiolabeled ligand for amyloid imaging, to detect fibrillary amyloid beta peptide (Aβ) accumulation, and examined characteristic AD pathologies with immunohistochemical staining of amyloid precursor protein (APP), Aβ, tau and phosphorylated tau (p-tau). mRNA studies showed significant downregulation of only two of 84 AD-related genes, Apbb1 and Lrp1, at 4 h after irradiation, and of only one gene, Il1α, at 1 year after irradiation. Spatial learning ability and memory were not significantly affected at 1 or 2 years after irradiation. No induction of amyloid fibrillogenesis or changes in APP, Aβ, tau, or p-tau expression was detected at 4 months or 2 years after irradiation. TBI induced early or late transcriptional alteration in only a few AD-related genes but did not significantly affect spatial learning, memory or AD-like pathological change in mice. (author)

  14. Optimal conditions of LDR to protect the kidney from diabetes: exposure to 12.5 mGy X-rays for 8 weeks efficiently protects the kidney from diabetes.

    Science.gov (United States)

    Cheng, Jie; Li, Fengsheng; Cui, Jiuwei; Guo, Weiying; Li, Cai; Li, Wei; Wang, Guixia; Xing, Xiao; Gao, Ying; Ge, Yuanyuan; Wang, Guanjun; Cai, Lu

    2014-05-08

    We reported the attenuation of diabetes-induced renal dysfunction by exposure to multiple low-dose radiation (LDR) at 25 mGy every other day by suppressing renal oxidative damage. We here explored the optimal conditions of LDR to protect the kidney from diabetes. Male C57BL/6J mice with type 1 diabetes were induced with multiple injections of low-dose streptozotocin. Diabetic mice received whole body X-irradiation at a dose of 12.5, 25 or 50 mGy every other day for either 4 or 8 weeks. Age-matched normal mice were similarly irradiated at the dose of 25 mGy for 4 or 8 weeks. The renal function and histopathological changes were examined at the 4th and 8th weeks of the study. Diabetes induced renal dysfunction is shown by the decreased creatinine and increased microalbumin in the urine. Renal oxidative damage, detected by protein nitration and lipid oxidation, and remodeling, reflected by increased expression of connective tissue growth factor, collagen IV and fibronectin, were significantly increased in diabetic mice. All these renal pathological and function changes in diabetic mice were significantly attenuated by exposure to LDR at all regimens, among which, however, exposure to LDR at 12.5 mGy for 8 weeks provided the best protective effect on the kidney of diabetic mice. Our results suggest that whole-body LDR at 12.5 mGy every other day for 8 weeks is the optimal condition of LDR to protect the kidney from diabetes. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. From nGy to MGy - new TL dosimetry of complex radiation at high-energy accelerators and thermonuclear fusion facilities

    International Nuclear Information System (INIS)

    Obryk, B.; Bilski, P.; Budzanowski, M.; Olko, P.

    2011-01-01

    One of the well known advantages of thermoluminescence (TL) detectors made of lithium fluoride doped with magnesium, copper and phosphorus (LiF:Mg,Cu,P) is their very high sensitivity to ionizing radiation. LiF:Mg,Cu,P detectors enable measurements of radiation doses from tens of nano grays up to a few kilo grays, when the total saturation of the signal of the so-called main dosimetric peak (at about 220 C. degrees) occurs. In 2006 for the first time we observed unprecedented high-temperature emission of LiF detectors heated to temperatures up to 600 C. degrees, after exposures to radiation doses ranging from 1 kGy to 1 MGy. For quantification of the glow curve shape changes of LiF:Mg,Cu,P detectors in this range of doses and determination of the absorbed dose, the high temperature coefficient (UHTR) was defined. This newly established dosimetric method was tested in a range of radiation qualities, such as gamma radiation, electron and proton beams, thermal neutron fields and in high-energy mixed fields around the SPS and PS accelerators at CERN. A number of dosimetric sets with LiF:Mg,Cu,P detectors are currently installed around the LHC at CERN. The new method for ultra-high dose range monitoring with a single LiF:Mg,Cu,P detector, which is capable of covering at least twelve orders of magnitude of doses, can be used for dosimetry at high energy accelerators and has great potential for accident dosimetry in particular. (authors)

  16. Optimization of Monocrystalline MgxCd1-xTe/MgyCd1-yTe Double-Heterostructure Solar Cells

    Science.gov (United States)

    Becker, Jacob J.

    Polycrystalline CdS/CdTe solar cells continue to dominate the thin-film photovoltaics industry with an achieved record efficiency of over 22% demonstrated by First Solar, yet monocrystalline CdTe devices have received considerably less attention over the years. Monocrystalline CdTe double-heterostructure solar cells show great promise with respect to addressing the problem of low Voc with the passing of the 1 V benchmark. Rapid progress has been made in driving the efficiency in these devices ever closer to the record presently held by polycrystalline thin-films. This achievement is primarily due to the utilization of a remote p-n heterojunction in which the heavily doped contact materials, which are so problematic in terms of increasing non-radiative recombination inside the absorber, are moved outside of the CdTe double heterostructure with two MgyCd1-yTe barrier layers to provide confinement and passivation at the CdTe surfaces. Using this design, the pursuit and demonstration of efficiencies beyond 20% in CdTe solar cells is reported through the study and optimization of the structure barriers, contacts layers, and optical design. Further development of a wider bandgap MgxCd1-xTe solar cell based on the same design is included with the intention of applying this knowledge to the development of a tandem solar cell constructed on a silicon subcell. The exploration of different hole-contact materials--ZnTe, CuZnS, and a-Si:H--and their optimization is presented throughout the work. Devices utilizing a-Si:H hole contacts exhibit open-circuit voltages of up to 1.11 V, a maximum total-area efficiency of 18.5% measured under AM1.5G, and an active-area efficiency of 20.3% for CdTe absorber based devices. The achievement of voltages beyond 1.1V while still maintaining relatively high fill factors with no rollover, either before or after open-circuit, is a promising indicator that this approach can result in devices surpassing the 22% record set by polycrystalline

  17. Very low-dose (0.15 mGy) chest CT protocols using the COPDGene 2 test object and a third-generation dual-source CT scanner with corresponding third-generation iterative reconstruction software.

    Science.gov (United States)

    Newell, John D; Fuld, Matthew K; Allmendinger, Thomas; Sieren, Jered P; Chan, Kung-Sik; Guo, Junfeng; Hoffman, Eric A

    2015-01-01

    The purpose of this study was to evaluate the impact of ultralow radiation dose single-energy computed tomographic (CT) acquisitions with Sn prefiltration and third-generation iterative reconstruction on density-based quantitative measures of growing interest in phenotyping pulmonary disease. The effects of both decreasing dose and different body habitus on the accuracy of the mean CT attenuation measurements and the level of image noise (SD) were evaluated using the COPDGene 2 test object, containing 8 different materials of interest ranging from air to acrylic and including various density foams. A third-generation dual-source multidetector CT scanner (Siemens SOMATOM FORCE; Siemens Healthcare AG, Erlangen, Germany) running advanced modeled iterative reconstruction (ADMIRE) software (Siemens Healthcare AG) was used.We used normal and very large body habitus rings at dose levels varying from 1.5 to 0.15 mGy using a spectral-shaped (0.6-mm Sn) tube output of 100 kV(p). Three CT scans were obtained at each dose level using both rings. Regions of interest for each material in the test object scans were automatically extracted. The Hounsfield unit values of each material using weighted filtered back projection (WFBP) at 1.5 mGy was used as the reference value to evaluate shifts in CT attenuation at lower dose levels using either WFBP or ADMIRE. Statistical analysis included basic statistics, Welch t tests, multivariable covariant model using the F test to assess the significance of the explanatory (independent) variables on the response (dependent) variable, and CT mean attenuation, in the multivariable covariant model including reconstruction method. Multivariable regression analysis of the mean CT attenuation values showed a significant difference with decreasing dose between ADMIRE and WFBP. The ADMIRE has reduced noise and more stable CT attenuation compared with WFBP. There was a strong effect on the mean CT attenuation values of the scanned materials for ring

  18. Qualification method for a 1 MGy-tolerant front-end chip designed in 65 nm CMOS for the read-out of remotely operated sensors and actuators during maintenance in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Verbeeck, Jens, E-mail: jens.verbeeck@esat.kuleuven.be [KU Leuven (KUL), Div. LRD-MAGyICS, Kasteelpark Arenberg 10, 3001 Heverlee (Belgium); Cao, Ying [KU Leuven (KUL), Div. LRD-MAGyICS, Kasteelpark Arenberg 10, 3001 Heverlee (Belgium); Van Uffelen, Marco; Casellas, Laura Mont; Damiani, Carlo; Morales, Emilio Ruiz; Santana, Roberto Ranz [Fusion for Energy (F4E), c/Josep, no. 2, Torres Diagonal Litoral, Ed. B3, 08019 Barcelona (Spain); Meek, Richard; Haist, Bernhard [Oxford Technologies Ltd. (OTL), 7 Nuffield Way, Abingdon OX14 1RL (United Kingdom); Hamilton, David [ITER Organisation (IO), Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul les Durance Cedex (France); Steyaert, Michiel [KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, 3001 Heverlee (Belgium); Leroux, Paul [KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, 3001 Heverlee (Belgium); KU Leuven, ESAT, Advanced Integrated Sensing Lab (AdvISe), Kleinhoefstraat 4, 2440 Geel (Belgium)

    2015-10-15

    This paper describes the radiation qualification procedure for a 1 MGy-tolerant Application Specific Integrated Circuit (ASIC) developed in 65 nm CMOS technology. The chip is intended for the read-out of electrical signals of sensors and actuators during maintenance in ITER. First the general working principle of the ASIC is shown. The developed IC allows to read-out, condition and digitize multiple low bandwidth (<10 kHz) sensors. In addition the IC is able to multiplex the digitized sensor signals. To comply with ITER-relevant constraints an adapted radiation qualification procedure has been proposed. The radiation-qualification procedure describes the test criteria and test conditions of the developed ASICs, which are also compared with COTS alternatives, to meet the stringent qualification procedures for electronics exposed to radiation in ITER.

  19. As-Deposited (La1-xSrx)(Ga1-y-zMgyCoz)O3-(x+y+z)/2 Crystallized Thin Films Prepared by Pulsed Laser Deposition for Application to Solid Oxide Fuel Cell Electrolyte

    Science.gov (United States)

    Mitsugi, Fumiaki; Kanazawa, Seiji; Ohkubo, Toshikazu; Nomoto, Yukiharu; Ishihara, Tatsumi; Takita, Yusaku

    2004-01-01

    Doped lanthanum gallate (La1-xSrx)(Ga1-y-zMgyCoz)O3-(x+y+z)/2 (LSGMCO) perovskite oxide films were deposited on a quartz glass, LaAlO3 single-crystal substrate and porous anode electrode of a solid oxide fuel cell (SOFC) by pulsed laser deposition. It was necessary to increase the substrate temperature up to 800°C for a crystallization of the LSGMCO films. The film deposited on the LaAlO3 single-crystal substrate grew along the c-axis. The as-deposited LSGMCO thick film fabricated on the porous substrate at 800°C and at an oxygen pressure of 20Pa was formed from polycrystal columns and showed a high conductivity of 0.7S/cm at a measurement temperature of 800°C. The activation energies were 0.72 eV at 600-800°C and 1.05 eV at 400-600°C.

  20. Specific considerations for obtaining appropriate La1-xSrxGa1-yMgyO3-δ thin films using pulsed-laser deposition and its influence on the performance of solid-oxide fuel cells

    Science.gov (United States)

    Hwang, Jaeyeon; Lee, Heon; Lee, Jong-Ho; Yoon, Kyung Joong; Kim, Hyoungchul; Hong, Jongsup; Son, Ji-Won

    2015-01-01

    To obtain La1-xSrxGa1-yMgyO3-δ (LSGM) thin films with the appropriate properties, pulsed-laser deposition (PLD) is employed, and specific considerations regarding control of the deposition parameters is investigated. It is demonstrated that with a target of stoichiometric composition, appropriate LSGM thin films cannot be produced because of the deviation of the composition from the target to the thin film. Only after adjusting the target composition an LSGM thin film with an appropriate composition and phase can be obtained. The optimized LSGM thin film possesses an electrical conductivity close to that of the bulk LSGM. In contrast, non-optimized thin films do not yield any measurable electrical conductivity. The impact of the optimization of the LSGM thin-film electrolyte on the cell performance is quite significant, in that a solid-oxide fuel cell (SOFC) with an optimized LSGM thin-film electrolyte produces a maximum power density of 1.1 W cm-2 at 600 °C, whereas an SOFC with a non-optimal LSGM thin-film electrolyte is not operable.

  1. Korruptsioonikonverents valitsuse ja kolmanda sektori koostöö heaks / Rait Kaarma, Kersti Kurre

    Index Scriptorium Estoniae

    Kaarma, Rait

    2004-01-01

    Eesti Maksumaksjate Liidu korraldatud rahvusvahelisest konverentsist "Korruptsioonivastane võitlus Eestis". Väljavõtted Avo Üpruse, Pille Kustovi, Bogdan Senschuki, Anne Schmidti ja Norman Aasa sõnavõttudest

  2. In situ X-ray and neutron diffraction of the Ruddlesden-Popper compounds (RE2-xSrx)0.98(Fe0.8Co0.2)1-yMgyO4-δ (RE=La, Pr): Structure and CO2 stability

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Hauback, B.C.; Hendriksen, Peter Vang

    2013-01-01

    The crystal structure of the Ruddlesden-Popper compounds (La 1.0Sr1.0)0.98Fe0.8Co 0.2O4-δ and (La1.2Sr0.8) 0.98(Fe0.8Co0.2)0.8Mg 0.2O4-δ was investigated at 1000 °C in N 2 (aO2=1×10-4) by in-situ powder neutron diffraction. In-situ powder X-ray diffraction (PXD) was also employed to investigate....... The equivalent pseudo-cubic thermal and chemical expansion coefficients are in agreement with values determined by dilatometry. The chemical stability in CO2 containing environments of various Ruddlesden-Popper compounds with chemical formula (RE2-xSr x)0.98(Fe0.8Co0.2) 1-yMgyO4-δ (RE=La, Pr), as well...

  3. Ülevaade tolli ja käibemaksu teabepäevast / Rait Kaarma, Mariliis Kannukene, Hiie Õunpuu

    Index Scriptorium Estoniae

    Kaarma, Rait

    2004-01-01

    30. märtsil toimunud teabepäevast tolli ja käibemaksu teemal. Ülevaade Heli Tariku, Ruth Paade, Lembar Kivistiku, Martin Hubergi ja Kaia Loobi sõnavõttudest. Lisad: kirjalik tollideklaratsioon (SAD) esitatakse, kui ; tollimaksumäärade, keeldude ja piirangutega saab tutvuda

  4. Pro-demokraatlik interventsioon : [bakalaureusetöö] / Rait Kaarma ; Tartu Ülikooli Õigusinstituut ; juhendaja: René Värk

    Index Scriptorium Estoniae

    Kaarma, Rait

    2003-01-01

    Demokraatia ja rahvusvaheline õigus, õiguse demokraatiale areng, sõjalise jõu kasutamine klassikalises sõjalises õiguses, pro-demokraatliku interventsiooni doktriin, unilateraalne ja kollektiivne pro-demokraatlik interventsioon

  5. Colour centres in LiF for measurement of abssorbed doses up to 100 MGy

    International Nuclear Information System (INIS)

    McLaughlin, W.L.

    1996-01-01

    Radiation damage studies on electronic components, polymers, composites, ceramics, metals and insulating materials exposed to very large doses of ionising photons and particles (i.e. electrons, protons, and neutrons) require reproducible and accurate passive dosimetry. Absorbed doses in the range 10 2 -2 x 10 6 Gy have previously been measured with optical quality, undoped LiF by spectrophotometry of radiation-induced absorption bands of stable colour centres. These include the relatively stable F centre (247 nm), M centre (443 nm), R 1 centre (315 nm), R 2 centre (374 nm), and N 2 centre (547 nm). It is now possible to extend this range to 10 8 Gy by spectrophotometry of the N 1 centre (517 nm) and an 'X' centre (785 nm). These dosemeters can be used from cryogenic (4 K) to relatively high radiation temperatures (up to 500 K). The radiation-induced coloration can be bleached for re-use of the dosemeters by a two hour thermal annealing treatment at 830 K. (Author)

  6. Ductility improvement by twinning and twin–slip interaction in a Mg-Y alloy

    International Nuclear Information System (INIS)

    Zhou, Na; Zhang, Zhenyan; Jin, Li; Dong, Jie; Chen, Bin; Ding, Wenjiang

    2014-01-01

    Highlights: • A high elongation of ∼33% was achieved for magnesium alloy through common extrusion. • Basal slip and extension twinning are the dominant deformation modes for the high ductility. • Non-basal slip, contraction twinning and twin-slip interaction also contribute to the ductility. - Abstract: An extruded Mg-3.0Y alloy with non-basal texture of 〈42 ¯ 2 ¯ 3〉 component was fabricated by common extrusion and exhibited a high elongation of ∼33%. The deformation modes and microstructure evolution of the extruded Mg-3.0Y alloy during the tensile test at room temperature were investigated to explore the reasons for the high ductility by transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD). The results suggested that texture changed from 〈42 ¯ 2 ¯ 3〉 to 〈101 ¯ 0〉 component during the tensile deformation, which is attributed the slip and twinning activity. Basal slip and extension twinning are the dominant deformation modes for the high ductility. Meanwhile, the activation of non-basal slip, contraction twinning and twin–slip interaction also contributes to the good ductility of Mg-3.0Y alloy

  7. MGI-oriented High-throughput Measurement of Interdiffusion Coefficient Matrices in Ni-based Superalloys

    Directory of Open Access Journals (Sweden)

    TANG Ying

    2017-01-01

    Full Text Available One of the research hotspots in the field of high-temperature alloys was to search the substitutional elements for Re in order to prepare the single-crystal Ni-based superalloys with less or even no Re addition. To find the elements with similar or even lower diffusion coefficients in comparison with that of Re was one of the effective strategies. In multicomponent alloys, the interdiffusivity matrix were used to comprehensively characterize the diffusion ability of any alloying elements. Therefore, accurate determination of the composition-dependant and temperature-dependent interdiffusivities matrices of different elements in γ and γ' phases of Ni-based superalloys was high priority. The paper briefly introduces of the status of the interdiffusivity matrices determination in Ni-based superalloys, and the methods for determining the interdiffusivities in multicomponent alloys, including the traditional Matano-Kirkaldy method and recently proposed numerical inverse method. Because the traditional Matano-Kirkaldy method is of low efficiency, the experimental reports on interdiffusivity matrices in ternary and higher order sub-systems of the Ni-based superalloys were very scarce in the literature. While the numerical inverse method newly proposed in our research group based on Fick's second law can be utilized for high-throughput measurement of accurate interdiffusivity matrices in alloys with any number of components. After that, the successful application of the numerical inverse method in the high-throughput measurement of interdiffusivity matrices in alloys is demonstrated in fcc (γ phase of the ternary Ni-Al-Ta system. Moreover, the validation of the resulting composition-dependant and temperature-dependent interdiffusivity matrices is also comprehensively made. Then, this paper summarizes the recent progress in the measurement of interdiffusivity matrices in γ and γ' phases of a series of core ternary Ni-based superalloys achieved in our research group. Up to now, the interdiffusivity matrices in γ and γ' phases of the core ternary systems including Ni-Al-X (X=Rh, Ta, W, Re, Os and Ir have been efficiently measured, and their reliability has also been carefully validated. Based on the experimental results, the interdiffusivities for different elements in Ni-based superalloys are carefully compared, from which the potential substitutional alloying elements for Re in Ni-based supperalloys as well as the points for alloy composition design are proposed. Finally, the research work of next step on the measurement of interdiffusivity matrices in Ni-based superalloys as well as the development trends of high-throughput measurement of interdiffusivities in our research group are pointed out.

  8. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana. Arvid Naess. Articles written in Sadhana. Volume 31 Issue 4 August 2006 pp 429-443. Estimation of failure probabilities of linear dynamic systems by importance sampling · Anna Ivanova Olsen Arvid Naess · More Details Abstract Fulltext PDF. An iterative method for estimating the failure ...

  9. Photoluminescence, modulation spectroscopy and surface photovoltage characterization of quaternary Zn1-x-yCdxMgySe compounds

    International Nuclear Information System (INIS)

    Dumcenco, D.O.; Levcenco, S.V.; Huang, Y.S.; Firszt, F.; Hsu, H.P.; Tiong, K.K.

    2011-01-01

    An optical characterization of wurtzite Zn 1-x-y Cd x Mg y Se crystalline alloys grown by the modified high-pressure Bridgman method has been carried out by temperature-dependent photoluminescence (PL) and contactless electroreflectance (CER) in the temperature range of 10-300 K, and photoreflectance (PR) measurements between 300-400 K as well as surface photovoltage spectroscopy (SPS) at 300 K. Low temperature PL spectra of the investigated samples consist of an excitonic line, the 'edge emission' due to radiative recombination of shallow donor-acceptor pairs and a broad band related to recombination through deep level defects. Three excitonic features, A, B and C, in the vicinity of band edge were observed in the CER and PR spectra. The peak positions of band-edge excitonic features in the PL spectra are shifted slightly towards lower energies as compared to the lowest corresponding transition energies of A exciton determined from CER and PR data. The increase of the CER-PL shift with the increasing of Mg content in the investigated crystals is explained by the rising of compositional disorder causing the smearing of the band-edge energies. In addition, the coincidence of energy positions of features obtained from SPS measurements with excitonic transition energies E 0 A determined from CER/PR data at 300 K confirm the proper surface treatment of the samples. (authors)

  10. Global radiation damage at 300 and 260 K with dose rates approaching 1 MGy s{sup −1}

    Energy Technology Data Exchange (ETDEWEB)

    Warkentin, Matthew; Badeau, Ryan; Hopkins, Jesse B. [Cornell University, Ithaca, NY 14853 (United States); Mulichak, Anne M.; Keefe, Lisa J. [Argonne National Laboratory, Argonne, IL 60439 (United States); Thorne, Robert E., E-mail: ret6@cornell.edu [Cornell University, Ithaca, NY 14853 (United States)

    2012-02-01

    Approximately half of global radiation damage to thaumatin crystals can be outrun at 260 K if data are collected in less than 1 s. Global radiation damage to 19 thaumatin crystals has been measured using dose rates from 3 to 680 kGy s{sup −1}. At room temperature damage per unit dose appears to be roughly independent of dose rate, suggesting that the timescales for important damage processes are less than ∼1 s. However, at T = 260 K approximately half of the global damage manifested at dose rates of ∼10 kGy s{sup −1} can be outrun by collecting data at 680 kGy s{sup −1}. Appreciable sample-to-sample variability in global radiation sensitivity at fixed dose rate is observed. This variability cannot be accounted for by errors in dose calculation, crystal slippage or the size of the data sets in the assay.

  11. Raman scattering in three-cation diluted magnetic semiconductor Cd1-x-yMnxMgyTe

    International Nuclear Information System (INIS)

    Agekyan, V.F.; Gridneva, L.K.; Karpov, S.V.; Serov, A.Yu.

    1995-01-01

    Investigations of Raman scattering (RS) in quaternary compounds were conducted to determine and interpret LO and TO frequencies, characterizing CdTe, MnTe, MgTe components in mixed crystal. Raman spectrum in the range of low frequencies is interpreted as interaction of quasi local vibrations with acoustic continuum

  12. Tondi Sõjakoolist laia maailma / Piret Kuusik ; juhendajad Merike Jürjo, Reet Viikholm

    Index Scriptorium Estoniae

    Kuusik, Piret

    2011-01-01

    Uurimistöö käsitleb Tondi Sõjakooliga seonduvat ning tolleaegseid etiketi- ja käitumisnorme. Töö annab ülevaate aspirant Arvid Tarsi ning temaga koos õppinud nelja kursuslase isikutest ja nende saatusest

  13. The CMS team celebrates the arrival of the "Tube". From left to right, sitting: Blanca Perea Solano, Jeannine Muffat-Joly, Ariella Cattai (Tracker Technical Coordinator). Standing: Georges Roiron, Hans Postema, Eric Albert, Paolo Petagna, Arvid Larsson, Nuno Bernardino Rodrigues, Enzo Carrone, Jack Hill.

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    CMS: Aerospace goes underground : gleaming aluminium on the outside and carbon black on the inside, as long as a sedan and taller than a man, a strange hollow cylinder arrived at CERN by truck August 26.

  14. Effect of Porous Structure on the Magnetic Properties of NixMgyZn1−x−yFe2O4 Magnetic Materials

    International Nuclear Information System (INIS)

    Qi Xin; Zhou Xin; Shu Di; Zhao Jing-Jing; Wang Wei; Chen Juan

    2011-01-01

    We deal with the preparation of NiMgZnFe III -SO 4 layered double hydroxides (LDHs) with the layered precursor method and introduce excessive ZnO into the NiMgZnFe III -SO 4 LDHs to produce Ni x Mg y Zn 1−x−y Fe 2 O 4 ferrites that contain massive ZnO. Then the Ni x Mg y Zn 1−x−y Fe 2 O 4 ferrites are treated with NaOH solution to remove ZnO to produce the porous Ni x Mg y Zn 1−x−y Fe 2 O 4 magnetic material: when y = 0, porous NiZnFe 2 O 4 ferrite magnetic materials are obtained; when y ≠ 0, porous NiMgZnFe 2 O 4 ferrite magnetic materials are obtained. From analyses of these two ferrites, their pore-forming mechanism and comparison of their properties before and after they undergo the alkali treatment, we find that after being treated by the NaOH solution, NiZnFe 2 O 4 /NiMgZnFe 2 O 4 have better uniform-structure pores, which will greatly expand their pore volume, widen their application scope and improve their magnetic properties. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  15. Assessment of the Prognostic and Treatment-Predictive Performance of the Combined HOXB13:IL17BR-MGI Gene Expression Signature in the Trans-ATAC Cohort

    Science.gov (United States)

    2013-12-01

    Shak S, Tang G, et al. A multigene assay to predict recurrence of tamoxifen-treated, node-negative breast cancer. N Engl J Med 2004; 351: 2817–26. 7...Barlow WE, Shak S, et al, for The Breast Cancer Intergroup of North America. Prognostic and predictive value of the 21-gene recurrence score assay in

  16. Use of the Materials Genome Initiative (MGI approach in the design of improved-performance fiber-reinforced SiC/SiC ceramic-matrix composites (CMCs

    Directory of Open Access Journals (Sweden)

    Jennifer S. Snipes

    2016-07-01

    Full Text Available New materials are traditionally developed using costly and time-consuming trial-and-error experimental efforts. This is followed by an even lengthier material-certification process. Consequently, it takes 10 to 20 years before a newly-discovered material is commercially employed. An alternative approach to the development of new materials is the so-called materials-by-design approach within which a material is treated as a complex hierarchical system, and its design and optimization is carried out by employing computer-aided engineering analyses, predictive tools and available material databases. In the present work, the materials-by-design approach is utilized to design a grade of fiber-reinforced (FR SiC/SiC ceramic matrix composites (CMCs, the type of materials which are currently being used in stationary components, and are considered for use in rotating components, of the hot sections of gas-turbine engines. Towards that end, a number of mathematical functions and numerical models are developed which relate CMC constituents’ (fibers, fiber coating and matrix microstructure and their properties to the properties and performance of the CMC as a whole. To validate the newly-developed materials-by-design approach, comparisons are made between experimentally measured and computationally predicted selected CMC mechanical properties. Then an optimization procedure is employed to determine the chemical makeup and processing routes for the CMC constituents so that the selected mechanical properties of the CMCs are increased to a preset target level.

  17. Eesti Filharmoonia Kammerkoor esineb Eestimaa külades

    Index Scriptorium Estoniae

    2008-01-01

    Reigi ja Emmaste kirikus 6. juunil, Kihelkonna ja Kaarma kirikus 7. juunil, Valjala ja Muhu kirikus 8. juunil, Viimsi Püha Jaakobi kirikus 10. juunil ja Harju-Madise Mattiase kirikus 11. juunil toimuvatest kontsertidest

  18. Klubi "Spirit" = Club Spirit / Hanno Soans ; tõlk. Liisi Ojamaa

    Index Scriptorium Estoniae

    Soans, Hanno, 1974-

    2000-01-01

    Eesti klubikultuurist 1990-ndatel. Klubi "Spirit" kujundusest. Sisearhitektid Tarmo Piirmets, Martti Siimann. Arhitekt Jüri Irik Arhitektuuribüroost Ehala & Irik. Projekt ja klubi valmis 2000. Flaierid kujundas Aadam Kaarma. 10 ill. Vaated, korruste plaanid

  19. Kadri Mälk ja Just Must / Mirjam Peil

    Index Scriptorium Estoniae

    Peil, Mirjam, 1939-

    2008-01-01

    Rahvusvaheline ehtekunstinäitus "Just Must" Eesti Ajaloomuuseumi Suurgildi hoones, kuraator Kadri Mälk ja kujundaja Taso Mähar. Osalesid 59 kunstnikku 18 riigist. Näitusega kaasneb Aadam Kaarma kujundatud kataloog. 10 fotot ehetest

  20. Rahvavalgustajad, teadlased, kirjanikud... / Helmut Piirimäe

    Index Scriptorium Estoniae

    Piirimäe, Helmut, 1930-

    1980-01-01

    Tartu Ülikooli ajaloost. Naabermaade kultuuriloosse oma tegevusega jälgi jätnud TÜ kasvandikest Georg Manzel (Mancelius), Christian Fürecker, Janis Reiters (Johannes Reuter), Olof (Olaus) Verelius, Isak Börk (Björk), Johannes Terserus, Abraham Thauvonius, Arvid Moller ja Petrus Schomerus

  1. Systems-theory of psychosis--the relevance of "internal censorship".

    Science.gov (United States)

    Emrich, H M; Leweke, F M; Schneider, U

    2006-02-01

    The different aspects of the neurobiology of psychotic disorders are presently discussed under the perspective of Arvid Calssons neurochemical theory of mesolimbic/cortico-thalamic loops. In this regard the question as to whether--neuropsychologically--a "filter-defect" or a disturbance of "internal censorship" is causative for psychoses. This topic is discussed in the present paper.

  2. Magnetic soft mode behaviour investigated via multi-spin flip Raman spectroscopy on near surface Cd1-xMnxTe/Cd1-yMgyTe quantum wells

    International Nuclear Information System (INIS)

    Kehl, Christian

    2011-01-01

    The main motivation for this thesis was the experimental confirmation of the theoretically predicted magnetic soft mode and the analysis of its dependence on the hole-concentration and external B-field, as well as its disappearance with increasing sample temperature. For that purpose, CdMnTe/CdMgTe QWs (Mn: 0.6%, 1.0%) positioned close to the sample surface (13-19 nm) were investigated in an in-plane applied external magnetic field (up to 4.5 T in Voigt-geometry) via a two-colour experiment i.e. using two light sources. This allows the spin excitation of Mn-ions by simultaneously tuning the hole-concentration towards the ferromagnetic phase transition by photo-generated carriers. Thus, one tuneable laser is responsible for resonant below-barrier excitation as a probe for Multi-SF Raman scattering. The other laser excites photo-generated carriers from above barrier (2.41 eV) for tuning the hole concentration in the QW. Positioning the QW close to the sample surface causes a surface-induced p-doping of the QW (intrinsic hole concentration in the QW) and enables the active tuning of the hole concentration by photo-generated carriers due to different tunnelling behaviour of electrons and holes from the QW to the surface. The Mn-g-factor was decreased by quasi-continuously increasing the above-barrier illumination, while the below-barrier excitation was kept at a constant low power. This results in a Mn-g-factor reduction starting from its atomic value g=2.01 to lowest evaluated Mn-g-factor in this thesis g=1.77. This is a magnetic softening of 12%. Apart from the general magnetic soft mode behaviour at low temperatures, one of the main experimental results in this thesis is the confirmation of the theoretical prediction that the magnetic soft mode behaviour in the external B-field does not only depend on the carrier concentration but also on the B-field strength itself. An additional aspect is the temperature dependence of the magnetic soft mode. The Mn-g-factor decrease is suppressed with increasing temperature almost reaching the atomic Mn-g-factor at 4.2 K (g=1.99). The results of the investigations concerning the cap layer thickness impact on the QW carrier characteristics were investigated in the cap thickness range of 13 nm to 19 nm. The cap thickness configures on the one hand the intrinsic hole concentration of the QW due to the surface-induced p-doping and sets the ''starting point'' for the Mn-g-factor reduction. On the other hand the cap thickness determines the probability of electron tunnelling to the surface and thus the efficiency of the hole tuning by light. The latter is the criterion for the range of Mn-g-factor reduction by light. This two dependences were pointed out by the photo-generated hole influence on the QW PL-spectra which results in tuning the exciton-trion ratio. In summary both mechanisms are of relevance for the hole tuning and thus for the magnetic soft-mode behaviour. The mechanism of tunnelling time prevails at small cap layer thicknesses while the surface-induced p-doping plays the major role for larger cap thicknesses (>25 nm). (orig.)

  3. Excitation functions of 120Te(d,xn)121,120m,gI reactions from threshold up to 13.5 MeV: comparative studies on the production of 120gI

    International Nuclear Information System (INIS)

    Hohn, A.; Coenen, H.H.; Qaim, S.M.

    2000-01-01

    Excitation functions of the nuclear reactions 120 Te(d,xn) 121,120m,g I were measured for the first time from their respective thresholds up to 13.5 MeV. Thin samples prepared by electrolytic deposition of 99.0% enriched 120 Te on Ti-backing were used. Integral yields of 121,120m,g I were calculated from the measured cross section data. A comparison of the 122 Te(p,3n)-, 120 Te(p,n)- and 120 Te(d,2n)-processes for the production of 120g I is given. The 120 Te(d,2n)-process is unsuitable for production purposes since the yield of 120g I is very low and the level of 121 I impurity very high. The choice lies either on the 122 Te(p,3n)- or the 120 Te(p,n)-reaction and is governed by the available proton energy and the financial resources for procuring the enriched target material

  4. Täna kell 18.30 avatakse Okupatsioonide muuseumis...

    Index Scriptorium Estoniae

    2004-01-01

    Linnakultuuriaineline näitus "Paraad". Keskne idee on seotud rula kui eluhoiakuga. Osalevad Tuukka & Kätlin Kaila ning Vaughan Baker (London), Jani Tolin ja Freeman (Helsingi), Aadam Kaarma, Anu Samarüütel, Tarrvi Laamann, Marko Mäetamm & Kaido Ole, Lazer, Väike J, Veronika Valk, DJ Critical

  5. Vabadus võtta vabalt / Maria-Kristiina Soomre

    Index Scriptorium Estoniae

    Soomre, Maria-Kristiina, 1978-

    2004-01-01

    Tänavakunstinäitus "Paraad" Eesti Lähimineviku Okupatsioonide Muuseumis. Osalevad Tuukka & Kätlin Kaila ning Vaughan Baker (London), Jani Tolin ja Freeman (Helsingi), Aadam Kaarma, Anu Samarüütel, Tarrvi Laamann, Marko Mäetamm & Kaido Ole, Lazer, Väike J, Veronika Valk, Kaarel Kulbin, DJ Critical

  6. "Ekspeditsioon Wunderlich" = "Expedition Wunderlich" / Carl-Dag Lige, Hannes Praks ; kommenteerinud Triin Ojari

    Index Scriptorium Estoniae

    Lige, Carl-Dag, 1982-

    2016-01-01

    Näitus "Ekspeditsioon Wunderlich" Eesti Arhitektuurimuuseumis. Autorid Katrin Talvik, Merilin Tee, Sabine Suuster, Martin Saar, Karl Taul, Alden Jõgisuu, Tõnu Lensment, Aadam Kaarma, Cael-Dag Lige, Hannes Praks. Näitus on Eesti Kunstiakadeemia ja Eesti Arhitektuurimuuseumi ühisprojekt

  7. Münchenis esitletakse Eesti juveelikunsti

    Index Scriptorium Estoniae

    2009-01-01

    Münchenis toimuval üritusel Schmuckzene esitletakse raamatut "Just Must", mis ilmus 2008. aastal Tallinnas samanimelise ehtekunstinäituse raames. Koostaja Kadri Mälk, kujundaja Aadam Kaarma, fotod Tanel Veenre. Kirjastus Arnoldsche Art Publishers arvas raamatu aasta viie parema ehtekunstiraamatu hulka

  8. Tallinna Kunstihoone, Bajozi Veinikelder ja AS Kiil & Co kuulutasid käesoleva aasta sügisel välja multiplitseeritava kunstiteose

    Index Scriptorium Estoniae

    2005-01-01

    Žürii (liikmed loetletud) valis välja Merike Estna, Maksim Surini, Andres Lõo, Evelin Kuusiku, Kärt Ojavee ja Aadam Kaarma teosed. Auhinnasaajate järjekord ja preemiad tehakse teatavaks konkursitööde näituse "Mitmik" avamisel Tallinna Kunstihoone galeriis 8. XII

  9. Nõukogude mood 1940. ja 50. aastatel / I. Andrejeva

    Index Scriptorium Estoniae

    Andrejeva, I.

    1985-01-01

    Sõjaaja riietusest, moejoonest. Moskva Moemajast (1949. aastast üleliiduline), moekunstnikke. Ajakirja "Zhurnal Mod" loomisest. 1940. aastate lõpuks kinnistunud moesuunast. Tegutsenud moemajad. Ajakirjas "Zhurnal Mod" (1954, nr. 2) väljakuulutatud kleidimudelite konkursi võitja - Melanie Kaarma, üks III preemia - Astrid Bulkina. S. Razumovskajalt artikkel "Eesti moekunstnikud" (Zhurnal Mod, 1954, nr. 3)

  10. Aia alt pilvekatusega kunstisaali / Meeli Müüripeal

    Index Scriptorium Estoniae

    Müüripeal, Meeli, 1963-

    2006-01-01

    Sabile restaureeritud sünagoog-kunstisaalist (1890).1993. a. läti skulptori Ojars Arvids Feldbergsi (sünd. 1947) poolt avatud Pedvale keskkonnakunsti keskusest, sealsetest Brinkpedvale (18. sajand) ja Frikspedvale mõisahoonetest. 1999. a. pälvis Pedvale vabaõhu kunstisaal UNESCO Melina Mercouri auhinna. Pedvales on tuleetendusega esinenud Raul Meel, eesti kunstnike töödest nimetatud Villu Jaanisoo töö "Tugitool". 16 ill

  11. Ehtekunsti kõrgmäestik Münchenis / Kadri Mälk, Piret Hirv, Tanel Veenre

    Index Scriptorium Estoniae

    Mälk, Kadri, 1958-

    2009-01-01

    Ehtekunsti suurüritusest "Schmuckszene" ("Ehtepaik"). Arnoldsche Art Publishers esitles viit aasta paremaks ehtekunstiraamatuks tituleeritut, nende seas Eestis trükikojas Pakett trükitud raamatut "Just must" (kujundaja Aadam Kaarma, fotod: Tanel Veenre). Darling Publications'i poolt esitletud raamatust "The Compendium Finale of Contemporary Jewellery Makes", kus tutvustatakse kümmet eesti ehtekunstnikku, tekstide autorid on Kadri Mälk, Harry Liivrand ja Tamara Luuk

  12. Kunstiakadeemia - 85 / Reet Varblane

    Index Scriptorium Estoniae

    Varblane, Reet, 1952-

    1999-01-01

    28. XI tähistas Eesti Kunstiakadeemia oma 85. aastapäeva. Kunstihariduse tulevikule pühendatud paneeldiskussioonist Sakala keskuse väikeses saalis, pressikonverentsist, pidulikust aktusest. Kunstiakadeemia esimesteks audoktoriteks promoveeriti Boris Bernshtein, Kaljo Põllu, Enno Hallek, Ilja Kabakov. Auliikmeteks nimetati Mari Adamson, Leo Gens, Leili Kuldkepp, Helene Kuma, Paul Luhtein, Arseni Mölder, Evald Okas, Helmut Oruvee, Bruno Tomberg, Jaan Vares. Juubelialbumi kujundas Jüri Kaarma, ajaloolise ülevaate kirjutas Leo Gens

  13. In situ X-ray and neutron diffraction of the Ruddlesden–Popper compounds (RE2−xSrx)0.98(Fe0.8Co0.2)1−yMgyO4−δ (RE=La, Pr): Structure and CO2 stability

    International Nuclear Information System (INIS)

    Chatzichristodoulou, C.; Hauback, B.C.; Hendriksen, P.V.

    2013-01-01

    The crystal structure of the Ruddlesden–Popper compounds (La 1.0 Sr 1.0 ) 0.98 Fe 0.8 Co 0.2 O 4−δ and (La 1.2 Sr 0.8 ) 0.98 (Fe 0.8 Co 0.2 ) 0.8 Mg 0.2 O 4−δ was investigated at 1000 °C in N 2 (a O2 =1×10 −4 ) by in-situ powder neutron diffraction. In-situ powder X-ray diffraction (PXD) was also employed to investigate the temperature dependence of the lattice parameters of the compounds in air and the oxygen activity dependence of the lattice parameters at 800 °C and 1000 °C. The thermal and chemical expansion coefficients, determined along the two crystallographic directions of the tetragonal unit cell, are highly anisotropic. The equivalent pseudo-cubic thermal and chemical expansion coefficients are in agreement with values determined by dilatometry. The chemical stability in CO 2 containing environments of various Ruddlesden–Popper compounds with chemical formula (RE 2−x Sr x ) 0.98 (Fe 0.8 Co 0.2 ) 1−y Mg y O 4−δ (RE=La, Pr), as well as their stability limit in H 2 /H 2 O=4.5 were also determined by in-situ PXD for x=0.9, 1.0 and y=0, 0.2. - Graphical abstract: Influence of electronic configuration on bond length, lattice parameters and anisotropic thermal and chemical expansion. Highlights: ► The thermal and chemical expansion coefficients are largely anisotropic. ► The expansion of the perovskite layers is constrained along the a direction. ► The studied compositions show remarkable thermodynamic stability upon reduction. ► The thermal and chemical expansion coefficients are lower than related perovskites. ► The investigated materials decompose in CO 2 containing atmospheres

  14. Comparison of X-ray radiation exposure during digital subtraction angiography (DSA) and multislice CT angiography (CTA)

    International Nuclear Information System (INIS)

    Bai, Mei; Liu, Bin; Zheng, Junzheng

    2008-01-01

    Full text: Purpose: To compare radiation risk during digital subtraction angiography (DSA) and CT angiography (CTA). Materials and methods: Eighty patients randomly divided into two groups of 40 patients each, were evaluated for coronary atherosclerotic heart disease with 64-slice spiral CT angiography and DSA respectively. For CTA group we divided patients into two subgroups: regular mode and ECG modulation mode. Matix of thermoluminescent dosimeters (TLDs) were placed on patients' skin surface during each examination to access peak skin dose (PSD). A male ART phantom was equipped with TLDs in six different positions to assess achievable organ dose. Effective dose was calculated by commercially available computer programs. Results: For DSA, PSD was 64mGy. Phantom organ dose for lung, heart, stomach, liver, kidney and brain were 11.07mGy, 5.87mGy, 1.42mGy, 2.11mGy, 6.76mGy and 0.001mGy respectively, and effective dose was 4mSv. For regular mode CTA, PSD was 74.5mGy, and CTD vol was 37.9mGy. Phantom organ dose for lung, heart, stomach, liver, kidney and brain were 58mGy, 64.2mGy, 6.6mGy, 9.9mGy, 2.7mGy, 0.072mGy respectively, and effective dose was 16mSv. For ECG modulation mode, PSD was 50.9mGy, and CTD vol was 26.3mGy. Conclusion: According to measured PSD value, deterministic radiation risk for regular mode CTA was little higher than DSA. However for stochastic radiation risk which can be indicated by organ dose and effective dose, regular mode CTA was much higher than DSA. Comparing with regular mode, ECG modulation mode can effectively reduce both stochastic and deterministic radiation risk. (author)

  15. Linnalood / Andri Ksenofontov ; kommenteerinud R[eet] V[arblane

    Index Scriptorium Estoniae

    Ksenofontov, Andri, 1962-

    2010-01-01

    Erki Kasemetsa näitus "Kohad/Cities Revealed" ja Liina Siibi näitus "Gimme Danger" sarjast "Cityscape" Tallinna Linnagaleriis. Näitus "Jüri Kaarma lugemistuba" Vabaduse Galeriis. Rühmituse Johnson&Johnson näitus "Nothing Left to Save" Draakoni galeriis. Karel Koplimetsa, Sigrid Viiri ja Taaniel Raudsepa kunstiprojekt "OÜ Visible Solutions" Hobusepea galeriis. Inglise kunstniku Pamela June Crooki isikunäitus galeriis Vaal. Peeter Lauritsa fotonäitus "Trickster's Office" ArtDepoo galeriis

  16. Eesti oma kunstisuveniirid

    Index Scriptorium Estoniae

    2005-01-01

    8. XII avati Tallinna Kunstihoone galeriis mitmikute näitus. Tallinna Kunstihoone, Bajozi veinikeldri ja AS Kiil & Co poolt 2005. a. sügisel väljakuulutatud mitmiku, käsitöönduslikult multiplitseeritava mahulise kunstiteose konkursi tulemused: I preemia (5000 kr.) - Merike Estna ja Maksim Shurini teos "Sound Picture", II (3000 kr.) - Andres Lõo "Jüri Arrak I" ja "J.A. I", III (2000 kr.) - Evelin Kuusiku "Pudel", eripreemia - Kärt Ojavee ja Aadam Kaarma "Albino"

  17. Kirikusisustus / Krista Kodres

    Index Scriptorium Estoniae

    Kodres, Krista, 1957-

    2005-01-01

    Luteri kirikus Eestis 16.-18. sajandil. Kantsel, arhitektoonika ja teoloogiline sõnum. Eesti vanimad kantslid (Rannu, Jämaja). Tallinna Püha Vaimu kiriku kantsel. Evangelisti-ja apostliprogrammid. Pildiseeriatega programmid -Tallinna Niguliste kiriku kantsel (T. Heintze, 1624), Kaarma kiriku kantsel (J. Jakobson, 1645), Kolga-Jaani kiriku kantsel (u. 1680.-90. aastad). Teksti osa kantsli kujunduses. Töökojad ja stiilide muutumine. Ristimisnõu, triumfikrutsifiks, pihitool, pingid, väärid, orelirõdud, lühtrid. Bilbiograafia lk. 457-458

  18. 2013 MDEQ-FEMA Rankin-Simpson Co. Lidar Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fugro as a subconsultant to MGI was authorized to undertake this project, as a part of Work Order No. 112, dated November 1, 2012, issued to MGI in accordance with...

  19. Adult exposures from MDCT including multiphase studies: first Italian nationwide survey

    Energy Technology Data Exchange (ETDEWEB)

    Palorini, Federica; Origgi, Daniela [Fisica Sanitaria Istituto Europeo di Oncologia, Milan (Italy); Granata, Claudio [UOC di Radiologia Istituto Giannina Gaslini, Genoa (Italy); Matranga, Domenica [Universita degli Studi di Palermo, Dipartimento di Scienze per la Promozione della Salute e Materno-infantile ' ' G. D' Alessandro' ' , Palermo (Italy); Salerno, Sergio [Policlinico Universita di Palermo, Dipartimento di Scienze Radiologiche, Palermo (Italy)

    2014-02-15

    To evaluate the radiation dose in routine multidetector computed tomography (MDCT) examinations in Italian population. This was a retrospective multicentre study included 5,668 patients from 65 radiology departments who had undergone common CT protocols: head, chest, abdomen, chest-abdomen-pelvis (CAP), spine and cardiac. Data included patient characteristics, CT parameters, volumetric CT dose index (CTDI{sub vol}) and dose length product (DLP) for each CT acquisition phase. Descriptive statistics were calculated, and a multi-regression analysis was used to outline the main factors affecting exposure. The 75th percentiles of CTDI{sub vol} (mGy) and DLP (mGy cm) for whole head were 69 mGy and 1,312 mGy cm, respectively; for chest, 15 mGy and 569 mGy cm; spine, 42 mGy and 888 mGy cm; cardiac, 7 mGy and 131 mGy cm for calcium score, and 61 mGy and 1,208 mGy cm for angiographic CT studies. High variability was present in the DLP of abdomen and CAP protocols, where multiphase examinations dominated (71 % and 73 % respectively): for abdomen, 18 mGy, with 555 and 920 mGy cm in abdomen and abdomen-pelvis acquisitions respectively; for CAP, 17 mGy, with 508, 850 and 1,200 mGy cm in abdomen, abdomen-pelvis and CAP acquisitions respectively. The results of this survey could help in the definition of updated diagnostic reference levels (DRL). (orig.)

  20. A survey of patients dose management in computed tomography with special emphasis to paetriatric patients in Ghana

    International Nuclear Information System (INIS)

    Inkoon, S.; Emi-Reynolds, G.; Boadu, M.; Schandorf, C.

    2010-01-01

    A survey of the frequency of common computed tomography (CT) examinations and the doses of six (6) CT facilities in Ghana has been undertaken. The technique factors for both adult and paediatric examinations were assessed. The dosimetric parameter used was the weighted computerized tomography dose index (CTDIw) for a single slice and the dose length product (DLP) for complete CT examinations of chest, chest high resolution (HR), lumbar spine, abdomen and pelvis. The effective dose (E) was estimated to give the stochastic radiation risk of a non-uniform exposure in terms of a whole body exposure. It was observed that some facilities used the same adult CT technique factors for paediatric patients. Mean values of adult CTDIw ranged as: chest (7.1-29.7 mGy), chest HR (7.1-30.0 mGy), lumbar spine (13.4-42.4 mGy), abdomen (7.8-42.4 mGy) and pelvis (8.9-42.4 mGy). Mean paediatric CTDIw values ranged as: chest (6.4-29.7 mGy), chest HR (6.4-30.0 mGy), lumbar spine (10.1-42.4 mGy), abdomen (10.1-42.4 mGy) and pelvis (10.1-42.4 mGy). The mean adult DLP values ranged as: chest (178-594 mGy cm), chest HR (168-594 mGy cm), lumbar spine (287-848 mGy cm), abdomen (233-848 mGy cm) and pelvis (228-848 mGy cm). However the mean paediatric DLP values ranged as: chest (128-594 mGy cm), chest HR (113-594 mGy cm), lumbar spine (253-848 mGy cm), abdomen (146-848 mGy cm) and pelvis (202-848 mGy cm). The E values for adults ranged as follows: chest (3.0-10.1 mSv), chest HR (2.9-10.1 mSv), lumbar spine (4.3-12.7 mSv), abdomen (3.5-12.7 mSv) and pelvis (4.3-12.7 mSv). The results show some agreement with diagnostic reference levels of CTDIw DLP and E values from literature. Nevertheless, further optimisation studies are needed to further reduce patient doses and modifications of technique factors especially for paediatrics (author)

  1. Patient dosimetry in hysterosalpingography

    International Nuclear Information System (INIS)

    Khoury, H.J.; Maia, A.; Oliveira, M.; Kramer, R.; Drexler, G.

    2001-01-01

    The objectives of this study were to determine the entrance surface dose to the patient and to estimate the dose to the uterus and ovaries due to hysterosalpingography (HSG) diagnostic examinations performed in Recife-Pe, Brazil. The entrance doses were measured using four thermoluminescent dosimeters per patient, attached to anatomical landmarks on the patient's skin. The study was carried out on 25 patients between 21 and 45 years of age who underwent the HSG examinations in two training hospitals and one private radiodiagnostic institute. The number of exposures performed ranged from 4 to 15 radiographs per patient measured. Entrance surface doses varied between 4.99 and 36.6 mGy, with an average of 12.6mGy. The doses to the ovaries and uterus ranged from 0.80 mGy to 5.8 mGy and 1.10mGy to 8.05 mGy, respectively. (author)

  2. Optimizing the balance between radiation dose and image quality in pediatric head CT: findings before and after intensive radiologic staff training.

    Science.gov (United States)

    Paolicchi, Fabio; Faggioni, Lorenzo; Bastiani, Luca; Molinaro, Sabrina; Puglioli, Michele; Caramella, Davide; Bartolozzi, Carlo

    2014-06-01

    The purpose of this study was to assess the radiation dose and image quality of pediatric head CT examinations before and after radiologic staff training. Outpatients 1 month to 14 years old underwent 215 unenhanced head CT examinations before and after intensive training of staff radiologists and technologists in optimization of CT technique. Patients were divided into three age groups (0-4, 5-9, and 10-14 years), and CT dose index, dose-length product, tube voltage, and tube current-rotation time product values before and after training were retrieved from the hospital PACS. Gray matter conspicuity and contrast-to-noise ratio before and after training were calculated, and subjective image quality in terms of artifacts, gray-white matter differentiation, noise, visualization of posterior fossa structures, and need for repeat CT examination was visually evaluated by three neuroradiologists. The median CT dose index and dose-length product values were significantly lower after than before training in all age groups (27 mGy and 338 mGy ∙ cm vs 107 mGy and 1444 mGy ∙ cm in the 0- to 4-year-old group, 41 mGy and 483 mGy ∙ cm vs 68 mGy and 976 mGy ∙ cm in the 5- to 9-year-old group, and 51 mGy and 679 mGy ∙ cm vs 107 mGy and 1480 mGy ∙ cm in the 10- to 14-year-old group; p training were significantly lower than the levels before training (p staff training can be effective in reducing radiation dose while preserving diagnostic image quality in pediatric head CT examinations.

  3. Memoriaalkunst / Krista Kodres

    Index Scriptorium Estoniae

    Kodres, Krista, 1957-

    2005-01-01

    Eestis uusajal. Surnu kujutisega hauaplaadid. Ballivi hauaplaat (1520) Tallinna Niguliste kirikus. O. Ryningi hauamonument (H. von Aken, 1594) ning P. De la Gardie ja S. Gyllenhielmi hauamonument (A. Passer, 1589-95) Tallinna toomkirikus. Passeri töökoja hauaplastika. 17. sajandi figuraalsed hauaplaadid. Heraldilised hauaplaadid ja tekstitahvlid. Raidkivist epitaafid (A. Passer, J. Winter, J. Hansson, B. Raschky). B. von Roseni kabeli ehissein (F. Hoppenstätt, 1655) Tallinna Niguliste kirikus. C. J Eckesparre perekonna epitaaf-uks (G. Böhme, 18. saj. keskpaik) Kaarma kirikus. J. Hastferi epitaaf (N. Millich?, A. Heroldt?, 1676) Tallinna toomkirikus. 17. sajandi lõpu ja 18. sajandi hauamonumendid (J. G. Stockenberg, J. G. Heroldt). Bilbiograafia lk. 458-460

  4. Estimation of radiation dose for adult and pediatric patients during X-ray examinations in Khartoum State

    International Nuclear Information System (INIS)

    Altahir, Ataalmanan Yosif Ataalmanan

    2018-01-01

    The aim of this study to evaluate the patient doses in X-ray examinations for skull and in three main hospitals in Khartoum State. The examination parameters took from 125 radiographs for both male and female were the females was 58 and the male 67 patients undergoing skull (AP), were the age of pediatric patients 1-18 years and adults 19-79 years. The result shows that the calculation of ESAK for according to gender for male skull 0.206 mGy, and ESAK according to gender for male skull 0.0719 mGy, for female skull 0.0942 mGy, for male chest 0.082 mGy and female for female chest 0.098 mGy. The calculation of ESAK according to patients age, adults and pediatric, the ESAK estimation for adults 0.122 mGy for skull, 0.1306 mGy for chest, and for pediatric 0.0432 mGy for skull, 0.055 mGy for chest. This data will be useful for the formulation of national reference levels as recommended by the International Atomic Energy Agency (IAEA). (Author)

  5. Radiation absorbed doses in cephalography

    International Nuclear Information System (INIS)

    Eliasson, S.; Julin, P.; Richter, S.; Stenstroem, B.

    1984-01-01

    Radiation absorbed doses to different organs in the head and neck region in lateral (LAT) and postero-anterior (PA) cephalography were investigated. The doses were measured by thermoluminescence dosimeters (TLD) on a tissue equivalent phantom head. Lanthanide screens in speed group 4 were used at 90 and 85 k Vp. A near-focus aluminium dodger was used and the radiation beam was collimated strictly to the face. The maximum entrance dose from LAT was 0.25 mGy and 0.42 mGy from a PA exposure. The doses to the salivary glands ranged between 0.2 and 0.02 mGy at LAT and between 0.15 and 0.04 mGy at PA exposures. The average thyroid gland dose without any shielding was 0.11 mGy (LAT) and 0.06 mGy (PA). When a dodger was used the dose was reduced to 0.07 mGy (LAT). If the thyroid gland was sheilded off, the dose was further reduced to 0.01 mGy and if the thyroid region was collimated out of the primary radiation field the dose was reduced to only 0.005 mGy. (authors)

  6. Biologically-Inspired Spike-Based Automatic Speech Recognition of Isolated Digits Over a Reproducing Kernel Hilbert Space

    Directory of Open Access Journals (Sweden)

    Kan Li

    2018-04-01

    Full Text Available This paper presents a novel real-time dynamic framework for quantifying time-series structure in spoken words using spikes. Audio signals are converted into multi-channel spike trains using a biologically-inspired leaky integrate-and-fire (LIF spike generator. These spike trains are mapped into a function space of infinite dimension, i.e., a Reproducing Kernel Hilbert Space (RKHS using point-process kernels, where a state-space model learns the dynamics of the multidimensional spike input using gradient descent learning. This kernelized recurrent system is very parsimonious and achieves the necessary memory depth via feedback of its internal states when trained discriminatively, utilizing the full context of the phoneme sequence. A main advantage of modeling nonlinear dynamics using state-space trajectories in the RKHS is that it imposes no restriction on the relationship between the exogenous input and its internal state. We are free to choose the input representation with an appropriate kernel, and changing the kernel does not impact the system nor the learning algorithm. Moreover, we show that this novel framework can outperform both traditional hidden Markov model (HMM speech processing as well as neuromorphic implementations based on spiking neural network (SNN, yielding accurate and ultra-low power word spotters. As a proof of concept, we demonstrate its capabilities using the benchmark TI-46 digit corpus for isolated-word automatic speech recognition (ASR or keyword spotting. Compared to HMM using Mel-frequency cepstral coefficient (MFCC front-end without time-derivatives, our MFCC-KAARMA offered improved performance. For spike-train front-end, spike-KAARMA also outperformed state-of-the-art SNN solutions. Furthermore, compared to MFCCs, spike trains provided enhanced noise robustness in certain low signal-to-noise ratio (SNR regime.

  7. Biologically-Inspired Spike-Based Automatic Speech Recognition of Isolated Digits Over a Reproducing Kernel Hilbert Space.

    Science.gov (United States)

    Li, Kan; Príncipe, José C

    2018-01-01

    This paper presents a novel real-time dynamic framework for quantifying time-series structure in spoken words using spikes. Audio signals are converted into multi-channel spike trains using a biologically-inspired leaky integrate-and-fire (LIF) spike generator. These spike trains are mapped into a function space of infinite dimension, i.e., a Reproducing Kernel Hilbert Space (RKHS) using point-process kernels, where a state-space model learns the dynamics of the multidimensional spike input using gradient descent learning. This kernelized recurrent system is very parsimonious and achieves the necessary memory depth via feedback of its internal states when trained discriminatively, utilizing the full context of the phoneme sequence. A main advantage of modeling nonlinear dynamics using state-space trajectories in the RKHS is that it imposes no restriction on the relationship between the exogenous input and its internal state. We are free to choose the input representation with an appropriate kernel, and changing the kernel does not impact the system nor the learning algorithm. Moreover, we show that this novel framework can outperform both traditional hidden Markov model (HMM) speech processing as well as neuromorphic implementations based on spiking neural network (SNN), yielding accurate and ultra-low power word spotters. As a proof of concept, we demonstrate its capabilities using the benchmark TI-46 digit corpus for isolated-word automatic speech recognition (ASR) or keyword spotting. Compared to HMM using Mel-frequency cepstral coefficient (MFCC) front-end without time-derivatives, our MFCC-KAARMA offered improved performance. For spike-train front-end, spike-KAARMA also outperformed state-of-the-art SNN solutions. Furthermore, compared to MFCCs, spike trains provided enhanced noise robustness in certain low signal-to-noise ratio (SNR) regime.

  8. Assessment of radiation exposure on a dual-source computed tomography-scanner performing coronary computed tomography-angiography

    International Nuclear Information System (INIS)

    Kirchhoff, S.; Herzog, P.; Johnson, T.; Boehm, H.; Nikolaou, K.; Reiser, M.F.; Becker, C.H.

    2010-01-01

    Objective: The radiation exposure of a dual-source-64-channel multi-detector-computed-tomography-scanner (Somatom-Defintion, Siemens, Germany) was assessed in a phantom-study performing coronary-CT-angiography (CTCA) in comparison to patients' data randomly selected from routine scanning. Methods: 240 CT-acquisitions of a computed tomography dose index (CTDI)-phantom (PTW, Freiburg, Germany) were performed using a synthetically generated Electrocardiography (ECG)-signal with variable heart rates (30-180 beats per minute (bpm)). 120 measurements were acquired using continuous tube-output; 120 measurements were performed using ECG-synchronized tube-modulation. The pulsing window was set at minimum duration at 65% of the cardiac cycle between 30 and 75 bpm. From 90-180 bpm the pulsing window was set at 30-70% of the cardiac cycle. Automated pitch adaptation was always used. A comparison between phantom CTDI and two patient groups' CTDI corresponding to the two pulsing groups was performed. Results: Without ECG-tube-modulation CDTI-values were affected by heart-rate-changes resulting in 85.7 mGray (mGy) at 30 and 45 bpm, 65.5 mGy/60 bpm, 54.7 mGy/75 bpm, 46.5 mGy/90 bpm, 34.2 mGy/120 bpm, 27.0 mGy/150 bpm and 22.1 mGy/180 bpm equal to effective doses between 14.5 mSievert (mSv) at 30/45 bpm and 3.6 mSv at 180 bpm. Using ECG-tube-modulation these CTDI-values resulted: 32.6 mGy/30 bpm, 36.6 mGy/45 bpm, 31.4 mGy/60 bpm, 26.8 mGy/75 bpm, 23.7 mGy/90 bpm, 19.4 mGy/120 bpm, 17.2 mGy/150 bpm and 15.6 mGy/180 bpm equal to effective doses between 5.5 mSv at 30 bpm and 2.6 mSv at 180 bpm. Significant CTDI-differences were found between patients with lower/moderate and higher heart rates in comparison to the phantom CTDI-results. Conclusions: Dual source CTCA is particularly dose efficient at high heart rates when automated pitch adaptation, especially in combination with ECG-based tube-modulation is used. However in clinical routine scanning for patients with higher heart rates

  9. Niche partitioning of marine group I Crenarchaeota in the euphotic and upper mesopelagic zones of the East China Sea.

    Science.gov (United States)

    Hu, Anyi; Jiao, Nianzhi; Zhang, Rui; Yang, Zao

    2011-11-01

    Marine group I Crenarchaeota (MGI) represents a ubiquitous and numerically predominant microbial population in marine environments. An understanding of the spatial dynamics of MGI and its controlling mechanisms is essential for an understanding of the role of MGI in energy and element cycling in the ocean. In the present study, we investigated the diversity and abundance of MGI in the East China Sea (ECS) by analysis of crenarchaeal 16S rRNA gene, the ammonia monooxygenase gene amoA, and the biotin carboxylase gene accA. Quantitative PCR analyses revealed that these genes were higher in abundance in the mesopelagic than in the euphotic zone. In addition, the crenarchaeal amoA gene was positively correlated with the copy number of the MGI 16S rRNA gene, suggesting that most of the MGI in the ECS are nitrifiers. Furthermore, the ratios of crenarchaeal accA to amoA or to MGI 16S rRNA genes increased from the euphotic to the mesopelagic zone, suggesting that the role of MGI in carbon cycling may change from the epipelagic to the mesopelagic zones. Denaturing gradient gel electrophoretic profiling of the 16S rRNA genes revealed depth partitioning in MGI community structures. Clone libraries of the crenarchaeal amoA and accA genes showed both "shallow" and "deep" groups, and their relative abundances varied in the water column. Ecotype simulation analysis revealed that MGI in the upper ocean could diverge into special ecotypes associated with depth to adapt to the light gradient across the water column. Overall, our results showed niche partitioning of the MGI population and suggested a shift in their ecological functions between the euphotic and mesopelagic zones of the ECS.

  10. An investigation into CT radiation dose variations for head examinations on matched equipment

    International Nuclear Information System (INIS)

    Zarb, Francis; Foley, Shane; Toomey, Rachel; Rainford, Louise; Holm, Susanne; Evanoff, Michael G.

    2016-01-01

    This study investigated radiation dose and image quality differences for computed tomography (CT) head examinations across centres with matched CT equipment. Radiation dose records and imaging protocols currently employed across three European university teaching hospitals were collated, compared and coded as Centres A, B and C from specification matched CT equipment models. Patient scans (n = 40) obtained from Centres A and C were evaluated for image quality, based on the visualisation of Commission of European Community (CEC) image quality criteria using visual grading characteristic (VGC) analysis, where American Board of Radiology examiners (n = 11) stated their confidence in identifying anatomical criteria. Mean doses in terms of CT dose index (CTDI vol -mGy) and dose length product (DLP-mGy cm) were as follows: Centre A-33.12 mGy and 461.45 mGy cm; Centre B -101 mGy (base)/32 mGy (cerebrum) and 762 mGy cm and Centre C-71.98 mGy and 1047.26 mGy cm, showing a significant difference (p ≤ 0.05) in DLP across centres. VGC analysis indicated better visualisation of CEC criteria on Centre C images (VGC AUC 0.225). All three imaging protocols are routinely used clinically, and image quality is acceptable in each centre. Clinical centres with identical model CT scanners have variously customised their protocols achieving a range of dose savings and still resulting in clinically acceptable image quality. (authors)

  11. Long-Term Musical Group Interaction Has a Positive Influence on Empathy in Children

    Science.gov (United States)

    Rabinowitch, Tal-Chen; Cross, Ian; Burnard, Pamela

    2013-01-01

    Musical group interaction (MGI) is a complex social setting requiring certain cognitive skills that may also elicit shared psychological states. We argue that many MGI-specific features may also be important for emotional empathy, the ability to experience another person's emotional state. We thus hypothesized that long-term repeated participation…

  12. Evaluation of radiation dose during the percutaneous angioplasty for arteriovenous shunt assembling

    Science.gov (United States)

    Ting, Chien-Yi; Wu, Wen-Shiann; Tang, Kuo-Ting; Wang, Hsin-Ell; Lin, Chun-Chih

    2017-11-01

    Percutaneous angioplasty (PTA) for dysfunctional hemodialysis is usually performed by radiologists, but not cardiologists, in Taiwan, so that the radiation dose in patients and physicians are usually unknown and related studies are rare. In this study, we are pioneering an investigation into the radiation dose in percutaneous angioplasty for arteriovenous shunt assembling and the effect of RADPAD device, a lead-free surgical drape containing Bi and Ba, on the decrease of a radiation dose in the non-targeted organs of the patient and also the operator. The radiation dose in a typical digital subtraction angiography (DSA) by the PTA protocol under a fixed field of view (FOV), was measured with optically simulated luminescent dosimeters arranged in a PIXY RS-102 anthropomorphic phantom. The results indicate that there is a significant dose reduction at the hands (0.022±0.002 mGy before treatment vs. 0.014±0.001 mGy after treatment; P=0.021), but not at the lens (0.027±0.003 mGy before treatment vs. 0.018±0.001 mGy after treatment; P=0.058), and the gonads (0.026±0.003 mGy before treatment vs. 0.020±0.001 mGy after treatment; P=0.058), of the cardiologist/operator after treatment with the RADPAD drape. At the patient's abdomen, the dose significantly decreased from 1.597±0.104 mGy to 0.031±0.002 mGy (PRADPAD shield. For the chest, lens and thyroid in the patient, the doses were respectively 0.154±0.100 mGy (compared to 0.049±0.001 mGy after treated with the RADPAD drape; P=0.0002), 0.066±0.001 mGy (compared to 0.021±0.001 mGy after the RADPAD treatment; P=0.009), and 0.208±0.002 mGy (compared to 0.042±0.003 mGy after shielded with the RADPAD drape; PRADPAD drape significantly reduced radiation exposure to the patient during the PTA for the arteriovenous shunt assembling, which is suggested should be applied to the current cardiac catheterization.

  13. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    Science.gov (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  14. The effects of low dose radiation (LDR) on mice of immune function

    International Nuclear Information System (INIS)

    Feng Li; Deng Daping

    2007-01-01

    Objective: To find out the Effects of Low Dose Radiation(LDR) on mice of immune function. Methods: Through flow cytometry to observe and analyse the effects of the leukomonocyte. Through immunohistochemistry to study IL-2, TNF-α. Results: At dose of 100mGy the stimulative effect on CD 4 + cells, CD 8 + cells and NK activity was higher than that at other doses. At dose of 500mGy leukomonocyte activity was lower. At dose of 100mGy, the colorations about IL-2, TNF-α deepen. Conclusion: LDR could stimulate immune function, especially at dose of 100mGy. while at dose of 500mGy, radiation could restrain the leukomonocyte activity. (authors)

  15. Measurement and estimation of maximum skin dose to the patient for different interventional procedures

    International Nuclear Information System (INIS)

    Cheng Yuxi; Liu Lantao; Wei Kedao; Yu Peng; Yan Shulin; Li Tianchang

    2005-01-01

    Objective: To determine the dose distribution and maximum skin dose to the patient for four interventional procedures: coronary angiography (CA), hepatic angiography (HA), radiofrequency ablation (RF) and cerebral angiography (CAG), and to estimate the definitive effect of radiation on skin. Methods: Skin dose was measured using LiF: Mg, Cu, P TLD chips. A total of 9 measuring points were chosen on the back of the patient with two TLDs placed at each point, for CA, HA and RF interventional procedures, whereas two TLDs were placed on one point each at the postero-anterior (PA) and lateral side (LAT) respectively, during the CAG procedure. Results: The results revealed that the maximum skin dose to the patient was 1683.91 mGy for the HA procedure with a mean value of 607.29 mGy. The maximum skin dose at the PA point was 959.3 mGy for the CAG with a mean value of 418.79 mGy; While the maximum and the mean doses at the LAT point were 704 mGy and 191.52 mGy, respectively. For the RF procedure the maximum dose was 853.82 mGy and the mean was 219.67 mGy. For the CA procedure the maximum dose was 456.1 mGy and the mean was 227.63 mGy. Conclusion: All the measured dose values in this study are estimated ones which could not provide the accurate maximum value because it is difficult to measure using a great deal of TLDs. On the other hand, the small area of skin exposed to high dose could be missed as the distribution of the dose is successive. (authors)

  16. Effect of gamma irradiation at intermediate doses on the performance of reverse osmosis membranes

    International Nuclear Information System (INIS)

    Combernoux, Nicolas; Labed, Véronique; Schrive, Luc; Wyart, Yvan; Carretier, Emilie; Moulin, Philippe

    2016-01-01

    The goal of this study is to explain the degradation of Polyamide (PA) composite reverse osmosis membrane (RO) in function of the irradiation dose. Irradiations were performed with a gamma 60 Co source in wet conditions and under oxygen atmosphere. For different doses of 0.2 and 0.5 MGy with a constant dose rate of 0.5 kGy h −1 , RO membranes performances (NaCl retention, permeability) were studied before and after irradiation. ATR-FTIR, ion chromatography and gas chromatography were used to characterize structural modification. Results showed that the permeability of RO membranes irradiated at 0.2 MGy exhibited a small decrease, related to scissions of the PVA coating. However, retention did not change at this dose. At 0.5 MGy, permeability showed a large increase of a factor around 2 and retention began to decrease from 99% to 95%. Chromatography measurements revealed a strong link between permselectivity properties variation, ion leakage and oxygen consumption. Add to ATR-FTIR observations, these results emphasized that the cleavages of amide and ester bonds were observed at 0.5 MGy, more precisely the loss of hydrogen bonds between polyamide chains. By different analysis, modifications of the polysulfone layer occur until a dose of 0.2 MGy. - Highlights: • Irradiation of RO membranes at intermediate dose (0.2 and 0.5 MGy). • For a dose rate of 0.5 kGy h −1 RO membranes are radiation resistant until 0.2 MGy. • Cleavages of polymer bonds in the active layer at 0.5 MGy. • Decrease in permselectivity properties of the membrane at 0.5 MGy. • High oxygen consumption between 0.2 and 0.5 MGy related to the membranes degradation.

  17. Report of questionnaire concerning the conditions and exposure doses at thoracoabdominal radiography and CT

    International Nuclear Information System (INIS)

    2009-01-01

    Japan Association of Radiological Technologists, at 2 years after its presentation of the Guideline for Medical Radiation Exposure (2006), made a questionnaire in the title on its homepage on Nov. 6-Dec. 5, 2008, and this paper is its report. The questionnaire asked the conditions and exposure doses at thoracoabdominal radiography and CT: in the former, asked were conditions like the machine/detector, tube voltage, filter, incident angle, entrance plane dose (EPD) (mGy) etc., and 237 facilities including 56 public hospitals and 15 universities answered. EPD calculated by numerical dose determination was found to be 0.22 and 0.76 mGy at the frontal and lateral thoracic projection, respectively, which were less than the upper limit defined in International Atomic Energy Agency (IAEA) guidance (0.4 and 1.5 mGy). However, doses in 6 and 2.6% of facilities at the respective projection exceeded the IAEA levels. EPD at the frontal abdominal projection calculated was 2.22 mGy, and all facilities met with the IAEA demand level (<10 mGy). In the CT questionnaire, conditions asked were the machine manufacturer/brand, scanning mode and range, tube voltage, rotation time, beam width and pitch, slice width, CTDIvol (CT Dose Index weighted/pitch) (mGy) and so on, which 212 facilities involving 58 public hospitals and 14 universities answered. CTDIvol was found to be 91.7 mGy at head CT which greatly exceeded the maximal levels of International Commission of Radiological Protection (ICRP), IAEA and the Association (60, 50 and 65 mGy, respectively). CTDIvol at thoracic CT was 15.2 mGy (no standard upper limit at present), and at abdominal CT, 20.0 mGy (the same as the Association level). The latter suggested the suitable dose setting at this CT. Thus the problem at head CT was much highlighted here. (K.T.)

  18. Study on human mesenchymal stem cells from bone marrow pretreated with low dose radiation

    International Nuclear Information System (INIS)

    Yang Yan; Wang Guangjun; Wang Juan

    2008-01-01

    Objective: To study effects of human bone marrow mesenchymal stem cells (hBM-MSC) from bone marrow pretreated with low dose radiation (LDR). Methods: The cells were the hBM-MSC. They were exposed to X rays at the dose of 50 mGy, 75 mGy, 100 mGy (dose rate 12.5 mGy/min). The growth curve, cell cycle and apoptosis of hBM-MSC treated by LDR were investigated. The content changes of stem cell factor(SCF), interleukin-6 (IL-6), macrophage colony stimulating factor(M-CSF) secreted by hBM-MSC after treated by LDR were determined by enzyme linked immunosorbent assay method. Results: The growth rates of hBM-MSC treated by LDR obviously increase from 72 h. The cell cycle and apoptosis were examined with FORTRAN Atomatic Checkout Systom. The results show that the G 0 /G 1 stage cells decrease after exposure to LDR, the percent of G 0 /G 1 stage cells of 75 mGy at 72 h is the lowest(30.86%). However, the S stage cells percentage gradually increase at 48 h and 72 h. The most one is 75 mGy group at 72 h, which reaches to 68.88%. The apoptosis percentages have increased tendency at 24 h and 48h in all dose groups, especially in 100 mGy at 24 h(25.99%), while have decreased tendency at 72 h and the most decreased group is the 50 mGy(6.8%), transient enhancement of apoptosis in the early stage and soon being decreased. The contents of SCF have increased tendency at 24 h, 48 h. As for IL-6, the contents in different dose groups at 24 h and 48 h have up-regulation. These groups, 50 mGy at 24 h, 48 h, 75 mGy at 24 h, 48 h, 100 mGy at 24 h have statistical difference compared with their control groups respectively. The content of IL-6 has greatest enhancement at dose of 50 mGy. The contents of M-SCF in all the groups at 24 h, 48 h and 72 h except for the 50 mGy dose at 72 h have also been found increased. The greatest increased content occur in the 75 mGy dose group at 72 h. Conclusion: This conclusion show that LDR has hormesis effect on hBM-MSC in cell growth, cell cycle and content

  19. Ultralow-dose CT of the craniofacial bone for navigated surgery using adaptive statistical iterative reconstruction and model-based iterative reconstruction: 2D and 3D image quality.

    Science.gov (United States)

    Widmann, Gerlig; Schullian, Peter; Gassner, Eva-Maria; Hoermann, Romed; Bale, Reto; Puelacher, Wolfgang

    2015-03-01

    OBJECTIVE. The purpose of this article is to evaluate 2D and 3D image quality of high-resolution ultralow-dose CT images of the craniofacial bone for navigated surgery using adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard filtered backprojection (FBP). MATERIALS AND METHODS. A formalin-fixed human cadaver head was scanned using a clinical reference protocol at a CT dose index volume of 30.48 mGy and a series of five ultralow-dose protocols at 3.48, 2.19, 0.82, 0.44, and 0.22 mGy using FBP and ASIR at 50% (ASIR-50), ASIR at 100% (ASIR-100), and MBIR. Blinded 2D axial and 3D volume-rendered images were compared with each other by three readers using top-down scoring. Scores were analyzed per protocol or dose and reconstruction. All images were compared with the FBP reference at 30.48 mGy. A nonparametric Mann-Whitney U test was used. Statistical significance was set at p ASIR-100 at 3.48 mGy, ASIR-100 at 2.19 mGy, and MBIR at 0.82 mGy. MBIR at 2.19 and 3.48 mGy scored statistically significantly better than the FBP reference (p = 0.032 and 0.001, respectively). For 3D images, the FBP reference at 30.48 mGy did not statistically significantly differ from all reconstructions at 3.48 mGy; FBP and ASIR-100 at 2.19 mGy; FBP, ASIR-100, and MBIR at 0.82 mGy; MBIR at 0.44 mGy; and MBIR at 0.22 mGy. CONCLUSION. MBIR (2D and 3D) and ASIR-100 (2D) may significantly improve subjective image quality of ultralow-dose images and may allow more than 90% dose reductions.

  20. Dosimetry for Patients undergoing Radiographic Examinations in Sudan

    International Nuclear Information System (INIS)

    Halato, M.A.; Kafi, S.T.; Ahmed, A.M.; Sid Ahamed, F.A.; Ibrahim, Z.; Suliman, M.F.; Suliman, I.I.

    2009-01-01

    In this study we estimated the entrance skin doses ESDs for patients undergoing selected diagnostic X -ray examinations in two large public hospitals in Khartoum state, Sudan. The study included the examinations of the chest posterior-anterior (PA) , skull antero-posterior (AP), skull Lateral (LAT) , Lumber spine AP/LAT, abdomen Intravenous urogram (IVU) and Pelvis AP. Totally, 241 patients were included in this study. ESDs were estimated from patients specific exposure parameters using established relation between output (μ Gy/mAs) and tube voltage (kVp). The estimated ESDs ranged from 0.18 - 1.05 mGy for chest PA, 0.98 - 3.48 mGy for Skull (AP), 0.66 - 2.75 mGy for skull (LAT), 1.22 - 4.35 mGy for abdomen (IVU), 1.18 - 5.75 mGy for Pelvis, 1.52 - 5.01 mGy Lumbar spine AP and 2.48 - 10.41 mGy for Lumbar spine (LAT). These values compare well with the international reference dose levels. This study provides additional data that can help the regulatory authority to establish reference dose level for diagnostic radiology in Sudan

  1. The Third International Intercomparison on EPR Tooth Dosimetry: Part 2, final analysis

    International Nuclear Information System (INIS)

    Wieser, A.; Debuyst, R.; Fattibene, P.; Meghzifene, A.; Onori, S.; Bayankin, S. N.; Brik, A.; Bugay, A.; Chumak, V.; Ciesielski, B.; Hoshi, M.; Imata, H.; Ivannikov, A.; Ivanov, D.; Junczewska, M.; Miyazawa, C.; Penkowski, M.; Pivovarov, S.; Romanyukha, A.; Romanyukha, L.; Schauer, D.; Scherbina, O.; Schultka, K.; Sholom, S.; Skvortsov, V.; Stepanenko, V.; Thomas, J. A.; Tielewuhan, E.; Toyoda, S.; Trompier, F.

    2006-01-01

    The objective of the Third International Intercomparison on EPR Tooth Dosimetry was to evaluate laboratories performing tooth enamel dosimetry <300 mGy. Final analysis of results included a correlation analysis between features of laboratory dose reconstruction protocols and dosimetry performance. Applicability of electron paramagnetic resonance (EPR) tooth dosimetry at low dose was shown at two applied dose levels of 79 and 176 mGy. Most (9 of 12) laboratories reported the dose to be within 50 mGy of the delivered dose of 79 mGy, and 10 of 12 laboratories reported the dose to be within 100 mGy of the delivered dose of 176 mGy. At the high-dose tested (704 mGy) agreement within 25% of the delivered dose was found in 10 laboratories. Features of EPR dose reconstruction protocols that affect dosimetry performance were found to be magnetic field modulation amplitude in EPR spectrum recording, EPR signal model in spectrum deconvolution and duration of latency period for tooth enamel samples after preparation. (authors)

  2. IN VITRO CULTURE OF HOLOPARASITE Rafflesia arnoldii R. Brown

    Directory of Open Access Journals (Sweden)

    Lazarus Agus Sukamto

    2010-07-01

    Full Text Available Potongan kuncup bunga digunakan sebagai eksplan yang ditumbuhkan pada media dasar Murashige and Skoog (MS dengan tambahan 0; 0.1; 0.5; 1 and 5 mg/I 2,4-D atau Picloram dan 2 g/I Phytagel. Eksplan tumbuh menjadi kalus pada media yang ditambahkan 0,1 dan 1 mg/I 2,4-D atau 0,5 dan 1 mg/I Picloram. Kultur kalus tersebut dipelihara pada media MS + 1 mg/I 2,4-D. Kemudian kalus ditumbuhkan pada medium dengan penambahan 1, 3, 5 dan 10 mg/I 2,4-D atau Picloram. Setelah dua bulan 66,67-100% kultur membentuk kalus. Semua kalus berstruktur kompak. Beberapa kalus yang diperlakuan dengan 5-10 mg/I 2,4-D menumbuhkan benang-benang putih pada permukaannya. Perlakuan Picloram menghasilkan kalus yang lebih banyak, tetapi 2,4-D menghasilkan kualitas kalus yang lebih baik. Kalus R. arnoldii tidak membentuk somatik embrio dengan penambahan 0,1 mg/I Zeatin dalam media kultur. Ini adalah laporan yang pertama kali tentang pembentukan kalus dari kultur R. arnoldii secara in vitro.

  3. Occupational and patient exposure in coronary angiography procedures

    International Nuclear Information System (INIS)

    Sulieman, A.; Alzimami, K.; Gafar, R.; Babikir, E.; Alsafi, K.; Suliman, I.I.

    2014-01-01

    Cardiac catheterization is the gold standard in the diagnosis and management of coronary artery diseases. The objectives of this study were to evaluate the radiation dose of patients and staff during cardiology procedures. Staff was monitored using thermoluminescence dosimeter (TLD) chips for 86 procedures. The mean patient dose was 2813.6 µGy m 2 and the mean fluoroscopic time was 4.8 min. The mean radiation doses for cardiologists were 0.9 mGy for the forehead, 0.92 mGy for the thyroid, 1.38 mGy for the chest, 1.28 mGy for the waist and 1.41 mGy for the hand. The mean radiation doses for assistants were 0.72 mGy for the chest, 0.82 mGy for the hand. High patient and staff exposure is due to lack of experience and protective equipment, exacerbated by a high workload. Interventional procedures remain operator dependent; therefore, continuous training is crucial. - Highlights: • Patients and staff radiation doses were evaluated during coronary angiography procedures. • Radiation doses were measured using calibrated TLD GR200A. • Radiation doses to patients and staff are comparable with previous studies. • Patient radiation doses fall below the threshold for radiation-induced skin injuries

  4. Determination of gonad, eye and bone marrow doses with EMI-5005 head and whole body scans

    International Nuclear Information System (INIS)

    Nishizawa, Kanae; Iwata, Takeo; Furuya, Yoshiro; Maruyama, Takashi; Hashizume, Tadashi.

    1979-01-01

    Dose determinations of tissues and organs during head and whole body scanning with an EMI computed tomographic equipment have been carried out using a Rando woman phantom. The surface dose on the phantom was measured with a Sakura lith Contact film dosimeter system. The absorbed doses in the eyes, thyroids, ovaries and the bone marrow were measured with a thermoluminescent dosimeter. The resultant surface doses for head scanning were 2.8 rad (28 mGy) per scan at maximum and 0.26 rad (2.6 mGy) per scan at minimum, and the doses for whole body scanning were 2.7 rad (27 mGy) per scan at maximum and 0.1 rad (1.0 mGy) per scan at minimum. For the complete gynecological scanning consisting of 8 slices, the eye, thyroid, ovary and the bone marrow dose was 2.4 mrad (24 μGy), 3.5 mrad (35 μGy), 500 mrad (5 mGy) and 225 mrad (2.25 mGy), respectively. And, for a typical head scanning consisting of 5 slices, the eye, thyroid, ovary and the bone marrow dose was 1400 mrad (14 mGy), 46 mrad (460 μGy), 0.60 mrad (6 μGy) and 73 mrad (730 μGy), respectively. (author)

  5. Measurements of radiation dose to patients undergoing some common radiographic x-ray examinations in Wad Madani hospitals

    International Nuclear Information System (INIS)

    Mohammedzein, T. S.

    2009-12-01

    The aim of this study was to assess patient doses in most common radiographic x-ray examinations in Wad Madani hospitals of Al Gazera State. The examination parameters of 388 radiographs were used to calculate the Entrance Surface Air Kerma (ESAK) of patients undergoing skull (AP and LAT), chest (PA), pelvis (AP), abdomen (AP) and lumbar spin (AP and LAT) in six major hospitals. Hospital mean ESAKs estimated range from 0.0729-0.69 mGy for chest PA, 0.338-6.64 mGy for skull PA, 0.195-5.8 mGy for skull LAT, 0.595-3.42 mGy for pelvis AP, 0.772-6.31 mGy for lumbar spine AP, 2.1-15.2 mGy for lumbar spine LAT and 0.742-5.79 mGy for abdomen. This data will be useful for the formulation of national reference levels as recommended by International Atomic Energy Agency (IAEA). (Author)

  6. Low-dose neutron dose response of zebrafish embryos obtained from the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility

    International Nuclear Information System (INIS)

    Ng, C.Y.P.; Kong, E.Y.; Konishi, T.; Kobayashi, A.; Suya, N.; Cheng, S.H.; Yu, K.N.

    2015-01-01

    The dose response of embryos of the zebrafish, Danio rerio, irradiated at 5 h post fertilization (hpf) by 2-MeV neutrons with ≤100 mGy was determined. The neutron irradiations were made at the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility in the National Institute of Radiological Sciences (NIRS), Chiba, Japan. A total of 10 neutron doses ranging from 0.6 to 100 mGy were employed (with a gamma-ray contribution of 14% to the total dose), and the biological effects were studied through quantification of apoptosis at 25 hpf. The responses for neutron doses of 10, 20, 25, and 50 mGy approximately fitted on a straight line, while those for neutron doses of 0.6, 1 and 2.5 mGy exhibited neutron hormetic effects. As such, hormetic responses were generically developed by different kinds of ionizing radiations with different linear energy transfer (LET) values. The responses for neutron doses of 70 and 100 mGy were significantly below the lower 95% confidence band of the best-fit line, which strongly suggested the presence of gamma-ray hormesis. - Highlights: • Neutron dose response was determined for embryos of the zebrafish, Danio rerio. • Neutron doses of 0.6, 1 and 2.5 mGy led to neutron hormetic effects. • Neutron doses of 70 and 100 mGy accompanied by gamma rays led to gamma-ray hormesis

  7. Estimation of entrance dose during selected fluoroscopic examinations in some hospitals in Khartoum state

    International Nuclear Information System (INIS)

    Mohammed, Heba Abdalkareem Osman

    2016-01-01

    A diagnostic fluoroscopy is a modality that involves visualizing the anatomy using radiation in real time. Therefore, patients doses have a potential for being great, increasing the chance of the radiation induced carcinogenesis. The objective of this study was to determine the mean entrance surface dose (ESD) from selected fluoroscopic examinations namely, hysterosalpingography (HSG) and ascendingurethogram (ASU) in three hospitals in Khartoum State. A total of 87 and 110 patents for HSG and ASU respectively were examined. The data were collected over four months. The mean ESD for patients who underwent HSG were 16.2 mGy, 20.6 mGy and 25.9 mGY respectively, while the ESD for patient who underwent ascendingurethrogram for AP view were 3.5mGy, 2.9mGy and 11.9mGy and for OB view 15.9 mGy, 18.3 mGy and 25.4 mGy. Patient doses were calculated using mathematical equation and the results were compared with the ESDs calculated using mathematical equation and the results were found to be comparable with the ESDs reported in previous studies and within the guidance level established by the ICRP. Fluoroscopy time, operator skills, x-ray machine type and clinical complexity of the procedures were shown to be major contributors to the variations reported in the measured ESDs. The study demonstrated the need for standardization of techniques throughout the hospitals and suggested that there ia a need to optimize the procedures.(Author)

  8. Dose evaluation in special fluoroscopy procedures: Hysterosalpingography and Dacryocystography; Avaliacao de dose em procedimentos especiais de fluoroscopia: histerossalpingografia e dacriocistografia

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Cintya Carolina Barbosa

    2006-04-15

    The hysterosalpingography (HSG) and dacryocystography (DCG) are among the special fluoroscopy procedures. The HSG is a radiodiagnostic technique used to detect uterine and tubal pathologies and it is fundamental for the investigation of infertility. The DCG is a form of lacrimal system imaging, being important to show the level of obstruction, the presence of dilatation of the lacrimal sac, as well as alterations in nearby structures. At this research, the study of skin entrance dose was evaluated for these two special fluoroscopy procedures, besides the analyses of staff doses whose performs the exams. The exams of 22 HSG patients and 8 DCG patients were evaluated using TL-100 dosimeters attached on patient' skin at anatomical landmarks evolved on each exam. In the case of HSG, the results showed that skin entrance doses varied from 0.5 mGy to 73.4 mGy, with an average value of 22.1 mGy. The estimated uterus dose was 5.5 mGy, and 6.6 mGy was the average dose estimated to the ovaries. The patient' skin entrance dose undergoing to DCG examinations varied from 2.1 mGy to 10.6 mGy, and the average eye's dose was 6.1 mGy. The results of staff dose showed that, on HSG, the average dose on doctor's right hand was 4.3 mGy per examination. This value had to the fact that the physician introduces the contrast manually while all contrast exposures. In relation of DCG, the staff's dose values were nearby background radiation, evidencing that, inside of permitted limits, there is no risk for the physicians at this procedure. (author)

  9. Validation of the mother-generated index in Iran: A specific postnatal quality-of-life instrument

    Directory of Open Access Journals (Sweden)

    Roghayeh Khabiri

    2013-01-01

    Full Text Available Background: The mother-generated index (MGI is one of only a few existing specific questionnaires for assessing the postnatal quality of life (QoL. MGI is a single-form questionnaire that asks postnatal mothers to specify up to eight areas of their lives which have been affected by giving birth to a baby. Using this tool, it is possible to score and rank the QoL of mothers. This study aimed to validate the questionnaire for use in Iran. Methods : Forward translation was used to translate the questionnaire from English to Farsi (Persian. The questionnaire was then administered to a sample of postnatal women attending two teaching hospitals in Tehran, Iran. Face validity and criterion validity were performed to establish the validity for the Iranian version of the MGI. Face validity was assessed by asking women to indicate whether they understood the wording of the questions, how easy the questionnaire was, and so on. Criterion validity was examined using the Short Form 36-item (SF-36 Health Survey. It was hypothesized that the MGI would significantly correlate with the SF-36. Results: In all, 124 women were approached. Of these, 119 women were eligible and 96 women agreed to take part in the study. Face validity was good and all of the women found the MGI straightforward to complete; as criterion validity, the MGI scores and the subscales of the SF-36 were moderately correlated (for all subscales: Pearson r > 0.4; P < 0.001. The mean MGI primary score was 5.38 (SD = 3.05. Women who had comorbidity had significantly lower MGI scores than women without comorbidity (P = 0.04. Correlation between aggregate of comments and primary score was high (r = 0.68, P < 0.01. Conclusions: In general, the Iranian version of the MGI performed well and our data suggest that it is a valid measure to assess health-related QoL among postnatal women.

  10. Dose evaluation in special fluoroscopy procedures: Hysterosalpingography and Dacryocystography; Avaliacao de dose em procedimentos especiais de fluoroscopia: histerossalpingografia e dacriocistografia

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Cintya Carolina Barbosa

    2006-04-15

    The hysterosalpingography (HSG) and dacryocystography (DCG) are among the special fluoroscopy procedures. The HSG is a radiodiagnostic technique used to detect uterine and tubal pathologies and it is fundamental for the investigation of infertility. The DCG is a form of lacrimal system imaging, being important to show the level of obstruction, the presence of dilatation of the lacrimal sac, as well as alterations in nearby structures. At this research, the study of skin entrance dose was evaluated for these two special fluoroscopy procedures, besides the analyses of staff doses whose performs the exams. The exams of 22 HSG patients and 8 DCG patients were evaluated using TL-100 dosimeters attached on patient' skin at anatomical landmarks evolved on each exam. In the case of HSG, the results showed that skin entrance doses varied from 0.5 mGy to 73.4 mGy, with an average value of 22.1 mGy. The estimated uterus dose was 5.5 mGy, and 6.6 mGy was the average dose estimated to the ovaries. The patient' skin entrance dose undergoing to DCG examinations varied from 2.1 mGy to 10.6 mGy, and the average eye's dose was 6.1 mGy. The results of staff dose showed that, on HSG, the average dose on doctor's right hand was 4.3 mGy per examination. This value had to the fact that the physician introduces the contrast manually while all contrast exposures. In relation of DCG, the staff's dose values were nearby background radiation, evidencing that, inside of permitted limits, there is no risk for the physicians at this procedure. (author)

  11. Dose evaluation in special fluoroscopy procedures: Hysterosalpingography and Dacryocystography

    International Nuclear Information System (INIS)

    Lopes, Cintya Carolina Barbosa

    2006-04-01

    The hysterosalpingography (HSG) and dacryocystography (DCG) are among the special fluoroscopy procedures. The HSG is a radiodiagnostic technique used to detect uterine and tubal pathologies and it is fundamental for the investigation of infertility. The DCG is a form of lacrimal system imaging, being important to show the level of obstruction, the presence of dilatation of the lacrimal sac, as well as alterations in nearby structures. At this research, the study of skin entrance dose was evaluated for these two special fluoroscopy procedures, besides the analyses of staff doses whose performs the exams. The exams of 22 HSG patients and 8 DCG patients were evaluated using TL-100 dosimeters attached on patient' skin at anatomical landmarks evolved on each exam. In the case of HSG, the results showed that skin entrance doses varied from 0.5 mGy to 73.4 mGy, with an average value of 22.1 mGy. The estimated uterus dose was 5.5 mGy, and 6.6 mGy was the average dose estimated to the ovaries. The patient' skin entrance dose undergoing to DCG examinations varied from 2.1 mGy to 10.6 mGy, and the average eye's dose was 6.1 mGy. The results of staff dose showed that, on HSG, the average dose on doctor's right hand was 4.3 mGy per examination. This value had to the fact that the physician introduces the contrast manually while all contrast exposures. In relation of DCG, the staff's dose values were nearby background radiation, evidencing that, inside of permitted limits, there is no risk for the physicians at this procedure. (author)

  12. Preliminary evaluation of exposures of computerized tomography patients in Latin America: IAEA project RLA/9/67

    International Nuclear Information System (INIS)

    Kodlulovich, S.; Silveira, V.; Khoury, H.J.

    2013-01-01

    The aim of this study was to obtain preliminary values of reference levels in CT . Were sent to each country forms with information of radiological protection and routine CT protocols. The CT dose index and absorbed dose to organs was estimated from the technical data for each equipment . The results showed that the total number of examinations performed 92 % are adult patients and 8 % are children. The most frequent examination of the skull was adult (40 % ) and abdomen for children (42 % ) . About the service , 67 % of the equipment are multicut and 76 % have specific protocols for pediatric patients. The CTDI vol values for head exams of adults vary between 2 and 352 mGy for pediatric patients under 1 year 1-191 mGy under 7 years old 5-335 mGy. For chest values ranged from 3 to 26 mGy for adults, between 1 and 89 mGy for children under 1 year and between 3-114 mGy for children between 1 and 7 years. Exams of the abdomen/pelvis of adults the range was 3-47 mGy , between 4-90 mGy for children under 1 year and between 2-31 mGy for children between 1 and 7 years. This study showed that although there are pediatric protocols, there is a wide variation in values of CTDl vol indicating a high potential for dose reduction. This result requires immediate action for optimization and implementation of diagnostic reference values in Latin America

  13. Preliminary evaluation of exposures of computerized tomography patients in Latin America: IAEA project RLA/9/67; Avaliacao preliminar das exposicoes de pacientes em tomografia computadorizada na America Latina: Projeto IAEA RLA/9/67

    Energy Technology Data Exchange (ETDEWEB)

    Kodlulovich, S.; Silveira, V. [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil); Khoury, H.J. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamcnto de Energia Nuclear; and others

    2013-07-01

    The aim of this study was to obtain preliminary values of reference levels in CT . Were sent to each country forms with information of radiological protection and routine CT protocols. The CT dose index and absorbed dose to organs was estimated from the technical data for each equipment . The results showed that the total number of examinations performed 92 % are adult patients and 8 % are children. The most frequent examination of the skull was adult (40 % ) and abdomen for children (42 % ) . About the service , 67 % of the equipment are multicut and 76 % have specific protocols for pediatric patients. The CTDI{sub vol} values for head exams of adults vary between 2 and 352 mGy for pediatric patients under 1 year 1-191 mGy under 7 years old 5-335 mGy. For chest values ranged from 3 to 26 mGy for adults, between 1 and 89 mGy for children under 1 year and between 3-114 mGy for children between 1 and 7 years. Exams of the abdomen/pelvis of adults the range was 3-47 mGy , between 4-90 mGy for children under 1 year and between 2-31 mGy for children between 1 and 7 years. This study showed that although there are pediatric protocols, there is a wide variation in values of CTDl{sub vol} indicating a high potential for dose reduction. This result requires immediate action for optimization and implementation of diagnostic reference values in Latin America.

  14. Radiation Measurement And Risk Estimation For Pediatric Patients During Routine Diagnostic Examination

    International Nuclear Information System (INIS)

    Bushra, E.; Sulieman, A.; Osman, H.

    2011-01-01

    The aim of the present work was to evaluate Entrance Surface Dose (ESD) to the patient using Thermo luminescence dosimeters (TLD) during some common routine pediatrics X-ray examinations in main pediatrics hospitals in Sudan. ESD and Effective Dose (E) for pediatrics have been carried out for 250 patients undergoing five different examinations. The mean ESD ranged for neonates ranged between 0.17 mGy-0.30 mGy per radiograph with scattered thyroid dose 0.01 to 0.19 mGy. The risk of radiation induced cancer of was 0.13 x 10-6.

  15. Evaluation of patient exposure with Flat Panel Detector (FPD) in X-ray TV system

    International Nuclear Information System (INIS)

    Yamada, M.; Komiya, N.; Kawaguchi, A.; Suzuki, M.; Suzuki, Shoichi; Asada, Yasuki

    2008-01-01

    The use of flat-panel detector (FPD) systems in TV equipment for gastrointestinal tract examination is increasing. The use of FPD systems is believed to reduce the exposure dose. When our institution changed its TV equipment from an image intensifier (GE; MS90Tj) system to an FPD (Shimadzu; SONIALVISION safire DAR-3500) system, we measured the doses produced and carried out a comparative examination of the extent to which exposure could be reduced. Two TV systems were used. We used an analyzer to measure output waveform, tube voltage, and half-value layer (HVL), and an ionization chamber dosimeter to carry out dose-in-air measurements. Body thickness, number of image acquisitions, and fluoroscopy time are required for the calculation of entrance skin dose (ESD). We therefore measured body thicknesses in 1000 upper gastrointestinal tract (UGI) and barium enemas and obtained average body thicknesses for males and females by age group. Values used for number of image acquisitions and fluoroscopy times were the averages in our institution over a two-year period. When an I.I. system was used, the average ESD during UGI examination were 126.8 mGy fluoroscopy dose and 11.62 mGy imaging dose, for an average total dose of 138.42 mGy per examination. ESD during barium enema averaged 201.73 mGy fluoroscopy dose and 45.2 mGy imaging dose, for an average total dose of 246.92 mGy per examination. When an FPD system was used, the average ESD during UGI examination were 58.71 mGy fluoroscopy dose and 5.72 mGy imaging dose, for an average total dose of 64.43 mGy per examination. ESD during barium enema averaged 112.21 mGy fluoroscopy dose and 24.55 mGy imaging dose, for an average total dose of 136.76 mGy per examination. The use of an FPD system reduced both fluoroscopy dose and imaging dose by 50%. The number of TV systems equipped with FPD in Japan has increased from around 1300 in 2006 to around 1700 in 2007. The use of FPD systems can be expected to increase in future. This

  16. Application of low-dose radiation protocols in survey CT scans

    International Nuclear Information System (INIS)

    Fu Qiang; Liu Ting; Lu Tao; Xu Ke; Zhang Lin

    2009-01-01

    Objective: To characterize the protocols with low-dose radiation in survey CT scans for localization. Methods: Eighty standard adult patients, head and body phantoms were recruited. Default protocols provided by operator's manual setting were that all the tube voltage for head, chest, abdomen and lumbar was 120 kV; the tube currents were 20,10,20 and 40 mA, respectively. Values of kV and mA in the low-dose experiments were optimized according to the device options. For chest and abdomen, the tube position were compared between default (0 degree) and 180 degree. Phantoms were scanned with above protocols, and the radiation doses were measured respectively. Paired t-test were used for comparisons of standard deviation in CT value, noise and exposure surface dose (ESD) between group with default protocols and group with optimized protocols. Results: The optimized protocols in low-dose CT survey scans were 80 kV, 10 mA for head, 80 kV, 10 mA for chest, 80 kV, 10 mA for abdomen and 100 kV, 10 mA for lumbar. The values of ESD for phantom scan in default and optimized protocols were 0.38 mGy/0.16 mGy in head, 0.30 mGy/0.20 mGy in chest, 0.74 mGy/0.30 mGy in abdomen and 0.81 mGy/0.44 mGy in lumbar, respectively. Compared with default protocols, the optimized protocols reduced the radiation doses 59%, 33%, 59% and 46% in head, chest, abdomen and lumbar. When tube position changed from 0 degree to 180 degree, the ESD were 0.24 mGy/0.20 mGy for chest; 0.37 mGy/0.30 mGy for abdomen, and the radiation doses were reduced 20% and 17%. Conclusion: A certain amount of image noise is increased in low-dose protocols, but image quality is still acceptable without problem in CT localization. The reduction of radiation dose and the radiation harm to patients are the superiority. (authors)

  17. Positron annihilation and thermally stimulated current of electron beam irradiated polyetheretherketone

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Shigetaka; Shinyama, Katsuyoshi; Baba, Makoto [Hachinohe Inst. of Tech., Hachinohe, Aomori (Japan); Suzuki, Takenori

    1997-03-01

    Positron lifetime measurements were applied to electron beam irradiated poly(ether-ether-ketone). The lifetime, {tau}{sub 3}, of the ortho-positronium of unirradiated and 5 MGy irradiated specimen became rapidly longer above about 150degC. {tau}{sub 3} of 50 MGy and 100 MGy irradiated specimen was shorter than that of unirradiated one. Thermally stimulated current (TSC) decreased with increasing the dose before voltage application. In the case of voltage application, a TSC peak appeared and the peak value decreased with increased the dose. The correlation between the results of positron annihilation and TSC was investigated. (author)

  18. Breast Radiation Dose With CESM Compared With 2D FFDM and 3D Tomosynthesis Mammography.

    Science.gov (United States)

    James, Judy R; Pavlicek, William; Hanson, James A; Boltz, Thomas F; Patel, Bhavika K

    2017-02-01

    We aimed to compare radiation dose received during contrast-enhanced spectral mammography (CESM) using high- and low-energy projections with radiation dose received during 2D full field digital mammography (FFDM) and 3D tomosynthesis on phantoms and patients with varying breast thickness and density. A single left craniocaudal projection was chosen to determine the doses for 6214 patients who underwent 2D FFDM, 3662 patients who underwent 3D tomosynthesis, and 173 patients who underwent CESM in this retrospective study. Dose measurements were also collected in phantoms with composition mimicking nondense and dense breast tissue. Average glandular dose (AGD) ± SD was 3.0 ± 1.1 mGy for CESM exposures at a mean breast thickness of 63 mm. At this thickness, the dose was 2.1 mGy from 2D FFDM and 2.5 mGy from 3D tomosynthesis. The nondense phantom had a mean AGD of 1.0 mGy with 2D FFDM, 1.3 mGy with 3D tomosynthesis, and 1.6 mGy with CESM. The dense breast phantom had a mean AGD of 1.3 mGy with 2D FFDM, 1.4 mGy with 3D tomosynthesis, and 2.1 mGy with CESM. At a compressed thickness of 4.5 cm, radiation exposure from CESM was approximately 25% higher in dense breast phantoms than in nondense breast phantoms. The dose in the dense phantom at a compressed thickness of 6 cm was approximately 42% higher than the dose in the nondense phantom at a compressed thickness of 4.5 cm. CESM was found to increase AGD at a mean breast thickness of 63 mm by approximately 0.9 mGy and 0.5 mGy compared with 2D FFDM and 3D tomosynthesis, respectively. Of note, CESM provides a standard image (similar to 2D FFDM) that is obtained using the low-energy projection. Overall, the AGD from CESM falls below the dose limit of 3 mGy set by Mammography Quality Standards Act regulations.

  19. Occupational external radiation exposure in the GDR in 1976

    International Nuclear Information System (INIS)

    Rothe, W.

    1980-01-01

    In 1976 a total of 36,794 occupationally exposed persons were monitored by the National Board of Nuclear Safety and Radiation Protection, using film badges. The monthly over-exposures (more than 4 mGy) totalled 415. In 11 cases the monthly exposure exceeded 30 mGy and 6 annual exposure values were in the range of 50 to 120 mGy. An attempt has been made to assess the annual collective and annual per caput doses for the exposed population as a whole and some subgroups without completely summing up the individual exposure data. (author)

  20. Evaluation of experimental animal biological state at exposure to low-dose ionizing radiation

    International Nuclear Information System (INIS)

    Rozanov, V.A.; Rejtarova, T.Je.; Chernyikov, G.B.; Timoshevs'ka, Je.V.; Kozozojeva, O.O.

    1997-01-01

    New approaches to quantitative evaluation of ionizing radiation absorbed dose within the low-dose range (up to 400 mGy) according to the degree of the organism biological response was developed. The purpose of the stage of the work published in Communication 1 is to evaluate the shifts in the animal behaviour and cellular composition of the blood at irradiation by the dose of 100,200 and 400 mGy. Distinct dose dependence of behaviour reactions and hematological indices within the dose range of 100-400 mGy was not noted

  1. Radiation dose in vertebroplasty

    International Nuclear Information System (INIS)

    Mehdizade, A.; Lovblad, K.O.; Wilhelm, K.E.; Somon, T.; Wetzel, S.G.; Kelekis, A.D.; Yilmaz, H.; Abdo, G.; Martin, J.B.; Viera, J.M.; Ruefenacht, D.A.

    2004-01-01

    We wished to measure the absorbed radiation dose during fluoroscopically controlled vertebroplasty and to assess the possibility of deterministic radiation effects to the operator. The dose was measured in 11 consecutive procedures using thermoluminescent ring dosimeters on the hand of the operator and electronic dosimeters inside and outside of the operator's lead apron. We found doses of 0.022-3.256 mGy outside and 0.01-0.47 mGy inside the lead apron. Doses on the hand were higher, 0.5-8.5 mGy. This preliminary study indicates greater exposure to the operator's hands than expected from traditional apron measurements. (orig.)

  2. Radiation hormesis of radish using an X-ray photography device

    Energy Technology Data Exchange (ETDEWEB)

    Sakuma, Atsushi [Asahikawa Kousei Hospital, Hokkaido (Japan)

    2000-07-01

    Radiation hormesis was studied at an X-ray photography room. Seed of radish (Kaiwaredaikon) was irradiated by X-ray, from 10 to 3000 mGy. Since the growth of plant was the highest around 500 mGy, 100 seeds were irradiated at a dose of 500 mGy. Fifty seeds were selected and the growth rate was measured after 1 and 2 weeks. After 2 weeks, the growth of the seeds irradiated (129{+-}5 mm) was found to be higher than those without irradiation (115{+-}5 mm). (author)

  3. Coronary cineangiography and ionizing radiation exposure to patients: analysis of primary and secondary beam

    International Nuclear Information System (INIS)

    Ramirez, Alfredo; Leyton, Fernando; Silva, Ana Maria; Farias, Eric

    2001-01-01

    The purpose of this work was to determine the level of exposure dose to patients during coronariographies in different areas of body. This study has presented the medical surveillance of 18 cases and the radiation monitoring of these patients by TLD in thyroid and pelvis (secondary beam) and, in the right and left scapular region (primary beam) for each one of these procedures. The ionizing radiation received was 215 ± 200 mGy in left scapular region (range 1-710) and 255±213 mGy in the right scapular region (range 22-635) p=NS. In the pelvic region the ionizing radiation was 0,22±0,06 mGy and in the thyroid region was 3,62±2,44 mGy

  4. Investigation of LiF, Mg and Ti (TLD-100 Reproducibility

    Directory of Open Access Journals (Sweden)

    Sadeghi M.

    2015-12-01

    Full Text Available LiF, Mg and Ti cubical TLD chips (known as TLD-100 are widely used for dosimetry purposes. The repeatability of TL dosimetry is investigated by exposing them to doses of (81, 162 and 40.5 mGy with 662keV photons of Cs-137. A group of 40 cubical TLD chips was randomly selected from a batch and the values of Element Correction Coefficient (ECC were obtained 4 times by irradiating them to doses of 81 mGy (two times, 162mGy and 40.5mGy. Results of this study indicate that the average reproducibility of ECC calculation for 40 TLDs is 1.5%, while these values for all chips do not exceed 5%.

  5. Investigation of LiF, Mg and Ti (TLD-100) Reproducibility.

    Science.gov (United States)

    Sadeghi, M; Sina, S; Faghihi, R

    2015-12-01

    LiF, Mg and Ti cubical TLD chips (known as TLD-100) are widely used for dosimetry purposes. The repeatability of TL dosimetry is investigated by exposing them to doses of (81, 162 and 40.5 mGy) with 662keV photons of Cs-137. A group of 40 cubical TLD chips was randomly selected from a batch and the values of Element Correction Coefficient (ECC) were obtained 4 times by irradiating them to doses of 81 mGy (two times), 162mGy and 40.5mGy. Results of this study indicate that the average reproducibility of ECC calculation for 40 TLDs is 1.5%, while these values for all chips do not exceed 5%.

  6. Dosimetry comparison of pelvimetry methods using conventional radiographs and CT

    International Nuclear Information System (INIS)

    Resten, A.; Suissa, M.; Musset, D.; Mausoleo, F.; Valero, M.; Taylor, S.

    2001-01-01

    To determine the fetal and maternal exposure to radiation by use of thermoluminescent dosimeters in order to compare conventional and CT-scan X-ray. Dosimetry was performed with an anthropomorph phantom. Thermoluminescent dosimeters were positioned on the surface and in the depth of the phantom. Digital radiography of the pelvis was performed according to a standard technique. CT-scan of the pelvis was performed according to the Buthiau's technique. With CT, the dose reached 0.31 to 4.95 mGy, with a dose of 2.32 mGy for the fetal gonads. With standard technique, the doses reached 0.03 to 0.39 mGy, with a dose of 0.39 mGy for the fetal gonads. With CT the fetus and the mother were exposed to 1/10. of the total dose delivered using conventional X-rays and the dose distribution was more homogeneous. (author)

  7. Evaluation of occupational and patient radiation doses in orthopedic surgery

    International Nuclear Information System (INIS)

    Sulieman, A.; Alzimami, K.; Habeeballa, B.; Osman, H.; Abdelaziz, I.; Sassi, S.A.; Sam, A.K.

    2015-01-01

    This study intends to measure the radiation dose to patients and staff during (i) Dynamic Hip Screw (DHS) and (ii) Dynamic Cannula Screw (DCS) and to evaluate entrance surface Air kerma (ESAK) dose and organ doses and effective doses. Calibrated Thermoluminescence dosimeters (TLD-GR200A) were used. The mean patients’ doses were 0.46 mGy and 0.07 mGy for DHS and DCS procedures, respectively. The mean staff doses at the thyroid and chest were 4.69 mGy and 1.21 mGy per procedure. The mean organ and effective dose for patients and staff were higher in DHS compared to DCS. Orthopedic surgeons were exposed to unnecessary radiation doses due to the lack of protection measures. The radiation dose per hip procedure is within the safety limit and less than the previous studies

  8. Maltese CT doses for commonly performed examinations demonstrate alignment with published DRLs across europe

    International Nuclear Information System (INIS)

    Zarb, F.; McEntee, M.; Rainford, L.

    2012-01-01

    This work recommends dose reference levels (DRLs) for abdomen, chest and head computerised tomography (CT) examinations in Malta as the first step towards national CT dose optimisation. Third quartiles volume CT dose index values for abdomen: 12.1 mGy, chest: 13.1 mGy and head: 41 mGy and third quartile dose-length product values for abdomen: 539.4, chest: 492 and head: 736 mGy cm -1 are recommended as Maltese DRLs derived from this first Maltese CT dose survey. These values compare well with DRLs of other European countries indicating that CT scanning in Malta is consistent with standards of good practice. Further work to minimise dose without affecting image quality and extending the establishment of DRLs for other CT examinations is recommended. (authors)

  9. Occupational radiation exposure in the GDR in 1980

    International Nuclear Information System (INIS)

    Poulheim, K.F.; Rothe, W.; Scheler, R.

    1982-01-01

    As in the previous year, the centralized monitoring of radiation workers for occupational exposure was carried out on the basis of film badges (38,781 persons), measurements with a whole-body counter and analyses of biosamples (351 persons in all). According to the film data, the monthly exposures exceeding 4 mGy totalled 682 including 48 doses higher than 10 mGy. Four workers received annual doses above 50 mGy, with the highest value being 1410 mGy. For the exposed population as a whole and some sub-groups, annual collective and mean annual doses have been given. In assessing internal exposure situation, use has been made of both data from the centralized monitoring program and those determined by some nuclear facilities themselves under the auspices of the SAAS. The results gave no indication of internal doses exceeding the annual limits of intake. (author)

  10. Occupational radiation exposure in the GDR in 1979

    International Nuclear Information System (INIS)

    Poulheim, K.F.; Rothe, W.; Scheler, R.

    1982-01-01

    As in the previous year, the centralized monitoring of radiation workers for occupational exposure was carried out on the basis of film badges (38,178 persons), measurements with a whole-body counter (247 persons) and analyses of biosamples (318 persons). According to the film data, the monthly exposures exceeding 4 mGy totalled 610 including 92 doses higher than 10 mGy. Six workers received annual doses above 50 mGy, with the highest value being 123 mGy. For the exposed population as a whole and some sub-groups, annual collective and mean annual doses have been given. In assessing the internal exposure situation, use has been made of both data from the centralized monitoring program and those determined by some nuclear facilities themselves under the auspices of the SAAS. The results gave no indication of internal doses exceeding the annual limits of intake. (author)

  11. Ultra-Fast All-Optical Self-Aware Protection Switching Based on a Bistable Laser Diode

    DEFF Research Database (Denmark)

    An, Yi; Vukovic, Dragana; Lorences Riesgo, Abel

    2014-01-01

    We propose a novel concept of all-optical protection switching with link failure automatic awareness based on AOWFF. The scheme is experimentally demonstrated using a single MG-Y laser diode with a record switching time ~200 ps....

  12. Evaluation of external and internal irradiation on uranium mining enterprise staff by tooth enamel EPR spectroscopy

    Science.gov (United States)

    Zhumadilov, Kassym; Ivannikov, Alexander; Khailov, Artem; Orlenko, Sergei; Skvortsov, Valeriy; Stepanenko, Valeriy; Kuterbekov, Kairat; Toyoda, Shin; Kazymbet, Polat; Hoshi, Masaharu

    2017-11-01

    In order to estimate radiation effects on uranium enterprise staff and population teeth samples were collected for EPR tooth enamel dosimetry from population of Stepnogorsk city and staff of uranium mining enterprise in Shantobe settlment (Akmola region, North of Kazakhstan). By measurements of tooth enamel EPR spectra, the total absorbed dose in the enamel samples and added doses after subtraction of the contribution of natural background radiation are determined. For the population of Stepnogorsk city average added dose value of 4 +/- 11 mGy with variation of 51 mGy was obtained. For the staff of uranium mining enterprise in Shantobe settlment average value of added dose 95 +/- 20 mGy, with 85 mGy variation was obtained. Higher doses and the average value and a large variation for the staff, probably is due to the contribution of occupational exposure.

  13. Coronary cineangiography and ionizing radiation exposure to patients: analysis of primary and secondary beam; Cineangiografia coronaria y radiacion ionizante a pacientes. Analisis en haz primario y secundario

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Alfredo; Leyton, Fernando; Silva, Ana Maria; Farias, Eric [Universidad de Chile, Santiago (Chile). Hospital Clinico; Gamarra, Jorge; Oyarzun, Carlos [Comision Chilena de Energia Nuclear (CCHEN), Santiago (Chile)

    2001-07-01

    The purpose of this work was to determine the level of exposure dose to patients during coronariographies in different areas of body. This study has presented the medical surveillance of 18 cases and the radiation monitoring of these patients by TLD in thyroid and pelvis (secondary beam) and, in the right and left scapular region (primary beam) for each one of these procedures. The ionizing radiation received was 215 {+-} 200 mGy in left scapular region (range 1-710) and 255{+-}213 mGy in the right scapular region (range 22-635) p=NS. In the pelvic region the ionizing radiation was 0,22{+-}0,06 mGy and in the thyroid region was 3,62{+-}2,44 mGy.

  14. Patient and staff dose during hysterosalpinography

    International Nuclear Information System (INIS)

    Buls, N.; Osteaux, M.

    2001-01-01

    Hysterosalpingography (HSG) is a useful and widely employed technique which uses X-ray fluoroscopy to investigate the female genital tract. Fluoroscopy is assessed by a gynaecologist, a physician who is not always trained to work with ionising radiation. Dose-area product measurements in a group of 34 patients allowed an estimation of the median effective dose (0,83 mSv) and the median dose to the ovaries (1,63 mGy) of the patient per procedure. The dose to the staff was estimated using thermoluminescent dosimetry. The following median entrance surface doses were estimated per procedure: 0,22 mGy to the lens of the eye, 0,15 mGy to the neck at thyroid level and 0,19 mGy to the back of the hand. The annual eye dose limit could be exceeded if the gynaecologist is a member of the public. (author)

  15. Survey of image quality and patient dose in simple radiographic examinations: establishing guidance levels and comparison with international standards

    International Nuclear Information System (INIS)

    Manatrakul, N.; Bunsoong, T.; Krisanachinda, A.; Suwanpradit, P.; Rungruengthanakit, P.; Kanchart, S.; Chaiwong, Rajikorn; Tsapakig, V.A.

    2008-01-01

    Purpose: To investigate image quality and patient dose for commonly radiographic examinations in Thailand, to establish national reference or guidance levels (GL) and compare with international standards, as part of an International Atomic Energy Agency (IAEA) project on Radiation Protection of Patients and Medical Exposure Control (RAS/9/034 and RAS/9/047). Materials and Methods: Film reject rate analysis, image quality and patient dose assessment before and after Quality Control (QC) implementation were investigated in 8 X-ray machines in 4 hospitals. Air kerma (in mGy) at 1 meter focus-detector-distance for different kVp settings for each X-ray machines were measured using an ionization chamber under standardized condition. The entrance skin air kerma (ESAK) for Chest PA, Lumbar spine AP, Lumbar spine LAT, Pelvis AP, Abdomen AP, Skull AP and Skull LAT were calculated for at least 10 adult patients of average body mass (60 to 80 kg) for each projection. The obtained values were compared with international standards. Results: The highest film rejection rate reduction recorded after corrective actions from 9.15% to 6.8%. Mean ESAK values were less than international standards both before and after QC implementation in all projections but Chest PA projection. Maximum ESAK in Chest PA projection before corrective action was 0.55 mGy which was higher than the IAEA GL of 0.2 mGy. However, it was reduced to 0.25 mGy after QC tests on X- ray machine and using high kilovoltage (kV) technique. Conclusion: Proposed national GL of Thailand were obtained by estimating the 3rd quartile of the whole sample: Chest PA: 0.1 mGy, Lumbar Spine AP: 2.1 mGy, Lumbar Spine LAT: 6.3 mGy, Pelvis AP: 1.8 mGy, Abdomen: 1.5 mGy, Skull PA: 1.3 mGy and Skull LAT: 0.9 mGy. (author)

  16. Thyroid Radiation Dose to Patients from Diagnostic Radiology Procedures over Eight Decades: 1930-2010.

    Science.gov (United States)

    Chang, Lienard A; Miller, Donald L; Lee, Choonsik; Melo, Dunstana R; Villoing, Daphnée; Drozdovitch, Vladimir; Thierry-Chef, Isabelle; Winters, Sarah J; Labrake, Michael; Myers, Charles F; Lim, Hyeyeun; Kitahara, Cari M; Linet, Martha S; Simon, Steven L

    2017-12-01

    This study summarizes and compares estimates of radiation absorbed dose to the thyroid gland for typical patients who underwent diagnostic radiology examinations in the years from 1930 to 2010. The authors estimated the thyroid dose for common examinations, including radiography, mammography, dental radiography, fluoroscopy, nuclear medicine, and computed tomography (CT). For the most part, a clear downward trend in thyroid dose over time for each procedure was observed. Historically, the highest thyroid doses came from the nuclear medicine thyroid scans in the 1960s (630 mGy), full-mouth series dental radiography (390 mGy) in the early years of the use of x rays in dentistry (1930s), and the barium swallow (esophagram) fluoroscopic exam also in the 1930s (140 mGy). Thyroid uptake nuclear medicine examinations and pancreatic scans also gave relatively high doses to the thyroid (64 mGy and 21 mGy, respectively, in the 1960s). In the 21st century, the highest thyroid doses still result from nuclear medicine thyroid scans (130 mGy), but high thyroid doses are also associated with chest/abdomen/pelvis CT scans (18 and 19 mGy for males and females, respectively). Thyroid doses from CT scans did not exhibit the same downward trend as observed for other examinations. The largest thyroid doses from conventional radiography came from cervical spine and skull examinations. Thyroid doses from mammography (which began in the 1960s) were generally a fraction of 1 mGy. The highest average doses to the thyroid from mammography were about 0.42 mGy, with modestly larger doses associated with imaging of breasts with large compressed thicknesses. Thyroid doses from dental radiographic procedures have decreased markedly throughout the decades, from an average of 390 mGy for a full-mouth series in the 1930s to an average of 0.31 mGy today. Upper GI series fluoroscopy examinations resulted in up to two orders of magnitude lower thyroid doses than the barium swallow. There are

  17. DNA alterations and effects on growth and reproduction in Daphnia magna during chronic exposure to gamma radiation over three successive generations

    International Nuclear Information System (INIS)

    Parisot, Florian; Bourdineaud, Jean-Paul; Plaire, Delphine; Adam-Guillermin, Christelle; Alonzo, Frédéric

    2015-01-01

    Highlights: • We exposed three successive generations of Daphnia magna to chronic gamma radiation. • We examined DNA alterations and effects on survival, growth and reproduction. • DNA alterations were accumulated over a generation and transmitted to the progeny. • Effects on survival and reproduction, and delay in growth increased over generations. - Abstract: This study examined chronic effects of external Cs-137 gamma radiation on Daphnia magna exposed over three successive generations (F0, F1 and F2) to environmentally relevant dose rates (ranging from 0.007 to 35.4 mGy h −1 ). Investigated endpoints included survival, growth, reproduction and DNA alterations quantified using random-amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). Results demonstrated that radiation effects on survival, growth and reproduction increased in severity from generation F0 to generation F2. Mortality after 21 days at 35.4 mGy h −1 increased from 20% in F0 to 30% in F2. Growth was affected by a slight reduction in maximum length at 35.4 mGy h −1 in F0 and by reductions of 5 and 13% in growth rate, respectively, at 4.70 and 35.4 mGy h −1 in F2. Reproduction was affected by a reduction of 19% in 21 day-fecundity at 35.4 mGy h −1 in F0 and by a delay of 1.9 days in brood release as low as 0.070 mGy h −1 in F2. In parallel, DNA alterations became significant at decreasing dose rates over the course of F0 (from 4.70 mGy h −1 at hatching to 0.007 mGy h −1 after ∼21 days) and from F0 to F2 (0.070 mGy h −1 at hatching to 0.007 mGy h −1 after ∼21 days), demonstrating their rapid accumulation in F0 daphnids and their transmission to offspring generations. Transiently more efficient DNA repair leading to some recovery at the organism level was suggested in F1, with no effect on survival, a slight reduction of 12% in 21 day-fecundity at 35.4 mGy h −1 and DNA alterations significant at highest dose rates only. The study improved our understanding of

  18. Evaluation of average glandular dose in mammography services in 10 cities of Colombia; Avaliacao de dose glandular media em servicos de mamografia de 10 cidades de Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Alejo-Martinez, H.; Salazar-Hurtado, E.; Puerto-Jimenez, D. [Grupo de Prevencion Temprana Del Cancer, Instituto Nacional de Cancerologia, Bogota D.C. (Colombia)

    2016-07-01

    The objective of this study was to conduct an assessment of dose in 60 mammography services that have screening programs for breast cancer in 10 cities of Colombia. The third quartile of the average glandular dose was 2,29 mGy, range between 1,0 and 5,6 mGy, for the phantom equivalent to a standard breast. This study included mammography units with conventional and digital technology. (author)

  19. Evaluation of average glandular dose in mammography services in 10 cities of Colombia

    International Nuclear Information System (INIS)

    Alejo-Martinez, H.; Salazar-Hurtado, E.; Puerto-Jimenez, D.

    2016-01-01

    The objective of this study was to conduct an assessment of dose in 60 mammography services that have screening programs for breast cancer in 10 cities of Colombia. The third quartile of the average glandular dose was 2,29 mGy, range between 1,0 and 5,6 mGy, for the phantom equivalent to a standard breast. This study included mammography units with conventional and digital technology. (author)

  20. Comparison of radiation absorbed dose in target organs in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography and computed tomography

    Directory of Open Access Journals (Sweden)

    Panjnoush M.

    2009-12-01

    Full Text Available "nBackground and Aim: The objective of this study was to measure and compare the tissue absorbed dose in thyroid gland, salivary glands, eye and skin in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography (CBCT and computed tomography (CT."nMaterials and Methods: Thermoluminescent dosimeters (TLD were implanted in 14 sites of RANDO phantom to measure average tissue absorbed dose in thyroid gland, parotid glands, submandibular glands, sublingual gland, lenses and buccal skin. The Promax (PLANMECA, Helsinki, Finland unit was selected for Panoramic, conventional linear tomography and cone beam computed tomography examinations and spiral Hispeed/Fxi (General Electric,USA was selected for CT examination. The average tissue absorbed doses were used for the calculation of the equivalent and effective doses in each organ."nResults: The average absorbed dose for Panoramic ranged from 0.038 mGY (Buccal skin to 0.308 mGY (submandibular gland, linear tomography ranged from 0.048 mGY (Lens to 0.510 mGY (submandibular gland,CBCT ranged from 0.322 mGY (thyroid glad to 1.144 mGY (Parotid gland and in CT ranged from 2.495 mGY (sublingual gland to 3.424 mGY (submandibular gland. Total effective dose in CBCT is 5 times greater than Panoramic and 4 times greater than linear tomography, and in CT, 30 and 22 times greater than Panoramic and linear tomography, respectively. Total effective dose in CT is 6 times greater than CBCT."nConclusion: For obtaining 3-dimensional (3D information in maxillofacial region, CBCT delivers the lower dose than CT, and should be preferred over a medical CT imaging. Furthermore, during maxillofacial imaging, salivary glands receive the highest dose of radiation.

  1. Patient exposures in Swedish diagnostic radiology

    International Nuclear Information System (INIS)

    Bengtsson, G.; Blomgren, P.-G.; Bergman, K.; Aaberg, L.

    1977-01-01

    Variations in doses between individuals and hospitals are discussed. Mean values and collective doses for Sweden are estimated. The mean annual collective dose per individual was estimated as follows: thyroid 0.75 mGy; mammae 0.54 mGy; lungs 0.64 mGy; bone marrow 0.92 mGy; ovaries 0.68 mGy and testes 0.65 mGy. The genetically significant dose was estimated as 0.7 mGy, a doubling since 1955. The annual mean whole body dose calculated from the energy imparted was 1.00 mGy. These figures should be subject to errors of about a factor of 2, mainly originating from the poor sampling technique. Some simplified risk estimates relating to the various examinations are made using the mean organ doses. These estimates indicated that within a factor of 3 up or down, the overall cancer risk might be 10 -4 J -1 , that is, an imparted energy of 10 000 J would lead to one radiation induced cancer. The estimate would apply to all examinations except those on extremities. The estimate of radiation induced cancer, uncertain as it may be, totals 8 cases per million Swedes per year, which is small compared with the natural cancer incidence of about 2000 per million and year. No corresponding simplification using energy absorbed seemed possible concerning the genetic risks. The study shows that using available examination techniques a dose reduction by a factor of 2 or more should be po

  2. Phototransfered thermoluminescence for dose reassessment in LiF:mg,ti , LiF: mg,Cu,p TL detectors

    International Nuclear Information System (INIS)

    Rodriguez Otazo, M.; Baly, L.

    2001-01-01

    Phototransfered Thermoluminescence (PTTL) from LiF:Mg,Ti (TLD-100) and LiF: Mg,Cu,P (GR-200) was studied at different conditions using different sources of UV light for dose reassessment purposes. The TL dosimeters were irradiated with 137Cs in the range 2 mGy to 100 mGy. The convenience of using PTTL for dose reassessment was analyzed

  3. Bridging the Gap: Linking Simulation and Testing

    Energy Technology Data Exchange (ETDEWEB)

    Krajewski, Paul E.; Carsley, John; Stoudt, Mark R.; Hovanski, Yuri

    2012-09-01

    The Materials Genome Initiative (MGI) which is a key enabler for the Advanced Manufacturing Partnership, announced in 2011 by U.S. President Barack Obama, was established to accelerate the development and deployment of advanced materials. The MGI is driven by the need to "bridge the gap" between (I) experimental results and computational analysis to enable the rapid development and validation of new mateirals, and (II) the processes required to convert these materials into useable goods.

  4. Emergency CT head and neck imaging: effects of swimmer's position on dose and image quality

    Energy Technology Data Exchange (ETDEWEB)

    Mueck, Fabian G.; Roesch, Sebastian; Geyer, Lucas; Scherr, Michael; Seidenbusch, Michael; Stahl, Robert; Deak, Zsuzsanna; Wirth, Stefan [LMU Klinikum Universitaet Muenchen (Germany). Inst. fuer Klinische Radiologie

    2014-05-15

    To compare the effects of different arm positions on dose exposure and image quality (IQ) in cervical spine CT after trauma in different patient groups. Patients in standard (STD = 126) and in swimmer's position (SWIM = 254) were included. Body mass index (BMI subgroup 1 = underweight to subgroup 4 = obese), anterior-posterior diameter (AP), left-right diameter (LR), area of an ellipse (AoE) and angle between the humeral heads (optimal STD < 3 , optimal SWIM > 10 ) were used as grouping criteria. Computed tomography dose index (CTDI) was documented. Two radiologists rated the IQ at three levels (CV1/2, CV4/5, CV7/T1) using a semi-quantitative scale (0 = not diagnostic, 1 = diagnostic with limitations, 2 = diagnostic without limitations). The Mann-Whitney U test correlations of grouping criteria with dose effects and intra-class correlation (ICC) were calculated. ICC was 0.87. BMI grouping showed the strongest correlation with dose effects: CTDI of optimal STD versus optimal SWIM positioning was 3.17 mGy versus 2.46 mGy (subgroup 1), 5.47 mGy versus 3.97 mGy (subgroup 2), 7.35 mGy versus 5.96 mGy (subgroup 3) and 8.71 mGy versus 8.18 mGy (subgroup 4). Mean IQ at CV7/T1 was 1.65 versus 1.23 (subgroup 1), 1.27 versus 1.46 (subgroup 2), 1.06 versus 1.46 (subgroup 3), 0.79 versus 1.5 (subgroup 4). Patients with a BMI > 20 kg/m{sup 2} benefited from both potential dose reduction and improved image quality at the critical cervicothoracic junction when swimmer's position was used. (orig.)

  5. Standardised approach to optimisation

    International Nuclear Information System (INIS)

    Warren-Forward, Helen M.; Beckhaus, Ronald

    2004-01-01

    Optimisation of radiographic images is said to have been obtained if the patient has achieved an acceptable level of dose and the image is of diagnostic value. In the near future, it will probably be recommended that radiographers measure patient doses and compare them to reference levels. The aim of this paper is to describe a standardised approach to optimisation of radiographic examinations in a diagnostic imaging department. A three-step approach is outlined with specific examples for some common examinations (chest, abdomen, pelvis and lumbar spine series). Step One: Patient doses are calculated. Step Two: Doses are compared to existing reference levels and the technique used compared to image quality criteria. Step Three: Appropriate action is taken if doses are above the reference level. Results: Average entrance surface doses for two rooms were as follows AP Abdomen (6.3mGy and 3.4mGy); AP Lumbar Spine (6.4mGy and 4.1mGy) for AP Pelvis (4.8mGy and 2.6mGy) and PA chest (0.19mGy and 0.20mGy). Comparison with the Commission of the European Communities (CEC) recommended techniques identified large differences in the applied potential. The kVp values in this study were significantly lower (by up to lOkVp) than the CEC recommendations. The results of this study have indicated that there is a need to monitor radiation doses received by patients undergoing diagnostic radiography examinations. Not only has the assessment allowed valuable comparison with International Diagnostic Reference Levels and Radiography Good Practice but has demonstrated large variations in mean doses being delivered from different rooms of the same radiology department. Following the simple 3-step approach advocated in this paper should either provide evidence that department are practising the ALARA principle or assist in making suitable changes to current practice. Copyright (2004) Australian Institute of Radiography

  6. Atrazine is primarily responsible for the toxicity of long-term exposure to a combination of atrazine and inorganic arsenic in the nigrostriatal system of the albino rat.

    Science.gov (United States)

    Bardullas, Ulises; Giordano, Magda; Rodríguez, Verónica Mireya

    2013-01-01

    Chronic and simultaneous exposure to a variety of chemicals present in the environment is an unavoidable fact. However, given the complexity of studying chemical mixtures, most toxicological studies have focused on the effects of short-term exposure to single substances. The aim of this study was to evaluate the effects on the nigrostriatal system of the chronic, simultaneous exposure to two widely distributed substances that have been identified as potential dopaminergic system toxicants, inorganic arsenic (iAs) and atrazine (ATR). Six groups of rats were treated daily for one year with atrazine (10mg ATR/kg), inorganic arsenic (0.5 or 50mgiAs/L of drinking water), or a combination of ATR+0.5mgiAs/L or ATR+50mgiAs/L. The 50mgiAs/L group showed locomotor hypoactivity, while all treatments decreased motor coordination in contrast no effects of treatment were found on the place and response learning tasks. Regarding markers for liver and muscle damage, there were no differences between groups in creatine kinase (CK) or aspartate transaminase (AST) activities, while decreases in lactate dehydrogenase (LDH) levels were found in some exposed groups. The striatal DA content was significantly reduced in ATR, 0.5mgiAs/L, ATR+0.5mgiAs/L, and ATR+50mgiAs/L groups, in comparison to the control group. The number of mesencephalic tyrosine hydroxylase positive cells decreased in the ATR and ATR+0.5mgiAs/L groups compared to the control. In contrast, immunoreactivity to cytochrome oxidase was reduced compared to the control in all treated groups, except for the group treated with 0.5iAsmg alone. Our results indicate that ATR has deleterious effects on dopaminergic neurons and that the combination of ATR and iAs does not exacerbate these effects. © 2013 Elsevier Inc. All rights reserved.

  7. A novel dendrimer based on poly (L-glutamic acid) derivatives as an efficient and biocompatible gene delivery vector

    International Nuclear Information System (INIS)

    Zeng Xin; Pan Shirong; Wang Chi; Wen Yuting; Wu Hongmei; Wang Cuifeng; Wu Chuanbin; Feng Min; Li Jie

    2011-01-01

    Non-viral gene delivery systems based on cationic polymers have faced limitations related to their relative low gene transfer efficiency, cytotoxicity and system instability in vivo. In this paper, a flexible and pompon-like dendrimer composed of poly (amidoamine) (PAMAM) G4.0 as the inner core and poly (L-glutamic acid) grafted low-molecular-weight polyethylenimine (PLGE) as the surrounding multiple arms was synthesized (MGI dendrimer). The novel MGI dendrimer was designed to combine the merits of size-controlled PAMAM G4.0 and the low toxicity and flexible chains of PLGE. In phosphate-buffered saline dispersions the well-defined DNA/MGI complex above a N/P ratio of 30 showed good stability with particle sizes of approximately 200 nm and a comparatively low polydispersity index. However, the particle size of the DNA/25 kDa polyethylenimine (DNA/PEI 25K) complex was larger than 700 nm under the same salt conditions. The shielding of the compact amino groups at the periphery of flexible PAMAM and biocompatible PLGE chains in MGI resulted in a dramatic decrease of the cytotoxicity compared to native PAMAM G4.0 dendrimer. The in vitro transfection efficiency of DNA/MGI dendrimer complex was higher than that of PAMAM G4.0 dendrimer. Importantly, in serum-containing medium, DNA/MGI complexes at their optimal N/P ratio maintained the same high levels of transfection efficiency as in serum-free medium, while the transfection efficiency of native PAMAM G4.0, PEI 25K and Lipofectamine 2000 were sharply decreased. In vivo gene delivery of pVEGF165/MGI complex into balloon-injured rabbit carotid arteries resulted in significant inhibition of restenosis by increasing VEGF165 expression in local vessels. Therefore, the pompon-like MGI dendrimer may be a promising vector candidate for efficient gene delivery in vivo.

  8. Breast dose reduction for chest CT by modifying the scanning parameters based on the pre-scan size-specific dose estimate (SSDE)

    Energy Technology Data Exchange (ETDEWEB)

    Kidoh, Masafumi; Utsunomiya, Daisuke; Oda, Seitaro; Nakaura, Takeshi; Yuki, Hideaki; Hirata, Kenichiro; Namimoto, Tomohiro; Sakabe, Daisuke; Hatemura, Masahiro; Yamashita, Yasuyuki [Kumamoto University, Department of Diagnostic Radiology, Faculty of Life Sciences, Honjo, Kumamoto (Japan); Funama, Yoshinori [Kumamoto University, Department of Medical Physics, Faculty of Life Sciences, Honjo, Kumamoto (Japan)

    2017-06-15

    To investigate the usefulness of modifying scanning parameters based on the size-specific dose estimate (SSDE) for a breast-dose reduction for chest CT. We scanned 26 women with a fixed volume CT dose index (CTDI{sub vol}) (15 mGy) and another 26 with a fixed SSDE (15 mGy) protocol (protocol 1 and 2, respectively). In protocol 2, tube current was calculated based on the patient habitus obtained on scout images. We compared the mean breast dose and the inter-patient breast dose variability and performed linear regression analysis of the breast dose and the body mass index (BMI) of the two protocols. The mean breast dose was about 35 % lower under protocol 2 than protocol 1 (10.9 mGy vs. 16.8 mGy, p < 0.01). The inter-patient breast dose variability was significantly lower under protocol 2 than 1 (1.2 mGy vs. 2.5 mGy, p < 0.01). We observed a moderate negative correlation between the breast dose and the BMI under protocol 1 (r = 0.43, p < 0.01); there was no significant correlation (r = 0.06, p = 0.35) under protocol 2. The SSDE-based protocol achieved a reduction in breast dose and in inter-patient breast dose variability. (orig.)

  9. Histological variations in liver of freshwater fish Oreochromis mossambicus exposed to 60Co gamma irradiation

    International Nuclear Information System (INIS)

    Sadiq Bukhari, A.; Syed Mohamed, H.E.; Broos, K.V.; Stalin, A.; Singhal, R.K.; Venubabu, P.

    2012-01-01

    The irradiation effect of 60 Co at the three dose level of 3 mGy, 30 mGy and 300 mGy on the histology of liver of the freshwater fish Oreochromis mossambicus was investigated. The liver of O. mossambicus was dissected out and processed for light microscopy studies. 60 Co exposed O. mossambicus were found to result in several alterations in the histoarchitecture of liver. The alterations included mild congestion of blood vessels, structural alteration, cellular swelling, vacuolation and necrotic liver cells, indicating a definite response to 60 Co irradiation. The results suggest that the liver of O. mossambicus exposed to 60 Co were structurally altered with increasing dose levels. It is to record that alteration in the liver does not affect the physiology, behaviour or lethality of the individuals. Self regulating mechanisms would have influenced the liver to remain sustained. To confirm the same further studies in the direction by increasing dose level is required. - Highlights: ► Fish Oreochromis mossambicus irradiated to the dose of 3 mGy, 30 mGy and 300 mGy. ► Histoarchitecture of liver altered with increasing dose levels of 60 Co. ► Alteration in the liver does not affect the physiology, behaviour or lethality. ► Self regulating mechanisms might have prevented from Lethality. ► HSI index value for exposed group reported ( 60 Co.

  10. Entrance radiation doses during paediatric cardiac catheterizations performed for diagnosis or the treatment of congenital heart disease

    International Nuclear Information System (INIS)

    Papadopoulou, D.; Yakoumakis, Em; Sandilos, P.; Thanopoulos, V.; Makri, Tr; Gialousis, G.; Houndas, D.; Yakoumakis, N.; Georgiou, Ev

    2005-01-01

    The purpose of this study was to estimate the radiation exposure of children, during cardiac catheterizations for the diagnosis or treatment of congenital heart disease. Radiation doses were estimated for 45 children aged from 1 d to 13 y old. Thermoluminescent dosemeters (TLDs) were used to estimate the posterior entrance dose (D P ), the lateral entrance dose (D LAT ), the thyroid dose and the gonads dose. A dose-area product (DAP) meter was also attached externally to the tube of the angiographic system and gave a direct value in mGy cm 2 for each procedure. Posterior and lateral entrance dose values during cardiac catheterizations ranged from 1 to 197 mGy and from 1.1 to 250.3 mGy, respectively. Radiation exposure to the thyroid and the gonads ranged from 0.3 to 8.4 mGy to 0.1 and 0.7 mGy, respectively. Finally, the DAP meter values ranged between 360 and 33,200 mGy cm 2 . Radiation doses measured in this study are comparable with those reported to previous studies. Moreover, strong correlation was found between the DAP values and the entrance radiation dose measured with TLDs. (authors)

  11. Radiation exposure of contrast-enhanced spectral mammography compared with full-field digital mammography.

    Science.gov (United States)

    Jeukens, Cécile R L P N; Lalji, Ulrich C; Meijer, Eduard; Bakija, Betina; Theunissen, Robin; Wildberger, Joachim E; Lobbes, Marc B I

    2014-10-01

    Contrast-enhanced spectral mammography (CESM) shows promising initial results but comes at the cost of increased dose as compared with full-field digital mammography (FFDM). We aimed to quantitatively assess the dose increase of CESM in comparison with FFDM. Radiation exposure-related data (such as kilovoltage, compressed breast thickness, glandularity, entrance skin air kerma (ESAK), and average glandular dose (AGD) were retrieved for 47 CESM and 715 FFDM patients. All examinations were performed on 1 mammography unit. Radiation dose values reported by the unit were validated by phantom measurements. Descriptive statistics of the patient data were generated using a statistical software package. Dose values reported by the mammography unit were in good qualitative agreement with those of phantom measurements. Mean ESAK was 10.5 mGy for a CESM exposure and 7.46 mGy for an FFDM exposure. Mean AGD for a CESM exposure was 2.80 mGy and 1.55 mGy for an FFDM exposure. Compared with our institutional FFDM, the AGD of a single CESM exposure is increased by 1.25 mGy (+81%), whereas ESAK is increased by 3.07 mGy (+41%). Dose values of both techniques meet the recommendations for maximum dose in mammography.

  12. Results of tooth enamel EPR dosimetry for population living in the vicinity of the Semipalatinsk nuclear test site

    Energy Technology Data Exchange (ETDEWEB)

    Zhumadilov, K. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan)], E-mail: kassym@hiroshima-u.ac.jp; Ivannikov, A. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan); Medical Radiological Research Center, Obninsk, 249036 (Russian Federation); Apsalikov, K. [Scientific-Research Institute for Radiation Medicine and Ecology, Semipalatinsk 490050 (Kazakhstan); Zhumadilov, Zh. [Semipalatinsk State Medical Academy, Semipalatinsk 490050 (Kazakhstan); Zharlyganova, D. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan); Stepanenko, V.; Skvortsov, V. [Medical Radiological Research Center, Obninsk, 249036 (Russian Federation); Berekenova, G. [Scientific-Research Institute for Radiation Medicine and Ecology, Semipalatinsk 490050 (Kazakhstan); Toyoda, S. [Department of Applied Physics Faculty of Science Okayama University of Science, 700-0005 (Japan); Endo, S.; Tanaka, K. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan); Miyazawa, C. [School of Dentistry, Ohu University, Koriyama-shi, Fukushima Pref. 963-8611 (Japan); Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, 734-8553 (Japan)

    2007-07-15

    The method of electron paramagnetic resonance (EPR) dosimetry was used on human tooth enamel to obtain individual absorbed doses of residents of settlements in the vicinity of the Nuclear Test Site (SNTS) in Semipalatinsk region, Kazakhstan. Measured teeth were extracted according to medical indications. In total, 105 tooth enamel samples were analyzed, including eight tooth samples from control settlement Kokpekty, which is located 400 km to the Southeast from SNTS and was not subjected to any radioactive contamination. It was found that the excess doses obtained after subtraction of the contribution of natural background radiation ranged up to about 440 mGy for residents of Dolon, whose tooth enamel was formed before 1949, and do not exceed 100 mGy for younger residents. For residents of Mostik, excess doses do not exceed 100 mGy for all ages except in one resident, for whom an extremely high dose of 1250 mGy was registered. For Bodene settlement, excess doses higher than 100 mGy were obtained for two samples from the residents having enamel formed before 1949. An extremely high dose (2800{+-}400 mGy) was obtained for one resident of Semipalatinsk City. The average excess dose for Semipalatinsk samples with enamel formation before 1949 was determined close to the average excess dose for tooth enamel samples from Dolon village.

  13. Investigating the embryo/larval toxic and genotoxic effects of {gamma} irradiation on zebrafish eggs

    Energy Technology Data Exchange (ETDEWEB)

    Simon, O., E-mail: olivier.simon@irsn.fr [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 186, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Massarin, S. [Laboratoire de Modelisation Environnementale, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 159, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Coppin, F. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 186, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Hinton, T.G. [Service d' Etude du Comportement des Radionucleides dans les Ecosystemes, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 159, BP3, 13115 Saint-Paul-lez-Durance Cedex (France); Gilbin, R. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Cadarache, Bat 186, BP3, 13115 Saint-Paul-lez-Durance Cedex (France)

    2011-11-15

    Eggs/larval of freshwater fish (Danio rerio) were exposed to low dose rates of external gamma radiation (from 1 to 1000 mGy d{sup -1}) over a 20-day period, with the objective of testing the appropriateness of the 10 mGy d{sup -1} guideline suggested by the IAEA. The present study examines different endpoints, mortality and hatching time and success of embryos as well as the genotoxicity of {gamma}-irradiations (after 48 h). The 20-day embryo-larval bioassay showed an enhanced larval resistance to starvation after chronic exposure to {gamma} irradiation (from low 1 mGy d{sup -1} to high dose rate 1000 mGy d{sup -1}) and an acceleration in hatching time. Gamma irradiation led to increased genotoxic damage Ito zebrafish egg (40-50% DNA in tail in Comet assay) from the lowest dose rate (1 mGy d{sup -1}). Possible mechanisms of {gamma} radiotoxicity and implications for radioprotection are discussed. - Highlights: > Relevant information on the {gamma} radiation impact on early life stage biota is scarce. > The eggs of zebrafish Danio rerio were selected as biological model. > We test the appropriateness of the 10 mGy d{sup -1} guideline (IAEA). > We observed effects measured at individual levels (starvation, hatching time). > Chronic gamma irradiation led to increased genotoxic damage to zebrafish egg. > {gamma} radiotoxicity mechanisms and implications for radioprotection are discussed.

  14. Adaptive response of apoptosis in EL-4 lymphoma cells induced by low dose radiation and its mechanism

    International Nuclear Information System (INIS)

    Liu Shuchun; Gong Pingsheng; Wang Zhicheng; Sun Liguang; Gong Shouliang

    2008-01-01

    EL-4 lymphoma cells were irradiated with the inductive doses (D1: 25-200 mGy, dose rate: 12.5mGy/min) and the challenging dose (D2:0.5-3.0 Gy, dose rate: 287 mGy/min), and the time interval between D1 and D2 was 6 h. The percentage of cell apoptosis and the expressive levels of cell apoptosis-associated gene pro- reins were measured with flow cytometry. The percentages of cell apoptosis in the D1 + D2 group with 25-100 mGy (D1) and 1.5 Gy (D2) or 75 mGy (D1) and 25-200 mGy (D2) were significantly lower than those in the D2 group. As compared with the D2 group, the positive percentage of cell Bcl-2 protein expression increased somewhat, and Bax decreased significantly, meanwhile the ratio of Bcl-2/Bax increased significantly and p53 decreased somewhat in D1 + D2 group with 25-100 mGy (D1) and 1.5 Gy (D2). The adaptive response of EL-4 lymphoma cell apoptosis could be induced by pre-irradiation with 25-100 mGy. Meantime, the expressive levels of cell apoptosis-associated gene Bcl-2, Bax and p53 proteins could change accordingly with cell apoptosis. These gene protein changes may play an important role in the mechanism of the adaptive response. (authors)

  15. Diagnostic Reference Levels for Patient Radiation Doses in Pelvis and Lumbar spine Radiography in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Yong; Lee, Byung Young; Lee, Jung Eun; Lee, Hyun Koo; Jung, Seunbg Hwan; Kim, Byung Woo; Kim, Hyeog Ju; Kim, Dong Sup [Radiation Safety Division National Institute of Food and Drug Safety Evaluation, Seoul (Korea, Republic of)

    2009-12-15

    entrance surface dose that patients receive during the pelvis and lumbar spine radiography show the following results: in the posteroanterior view of pelvis radiography, the minimum value is 0.59 mGy, the maximum value is 12.69 mGy and the average value is 2.88 mGy with the 1st quartile value being 1.91 mGy, the median being 0.59 mGy, and the 3rd quartile value being 3.43 mGy. Also, in the posteroanterior view of lumbar spine radiography, the minimum value is 0.64 mGy, the maximum value is 23.84 mGy, and the average value is 3.68 mGy with the 1st quartile value being 2.41 mGy, the median being 3.40 mGy, and the 3rd quartile value being 4.08 mGy. In the lateral view of lumbar spine radiography, the minimum value is 1.90 mGy, the maximum value is 45.42 mGy, and the average value is 10.08 mGy with the 1st quartile value being 6.03 mGy, the median being 9.09 mGy and the 3rd quartile value being 12.65 mGy. The diagnostic reference levels for patient radiation dose to be recommended to the medical institutes in Korea is 3.42 mGy for the posteroanterior view of pelvis radiography, 4.08 mGy for the posteroanterior view of lumbar spine radiography, and 12.65 mGy for the lateral view of lumbar spine radiography. Such values are all lower than the values recommended by 6 international organizations including World Health Organization, where the recommended values are 10 mGy for the posteroanterior view of pelvis radiography, 10 mGy for the posteroanterior view of lumbar spine radiography and 30 mGy for the lateral view of lumbar spine radiography.

  16. Diagnostic Reference Levels for Patient Radiation Doses in Pelvis and Lumbar spine Radiography in Korea

    International Nuclear Information System (INIS)

    Lee, Kwang Yong; Lee, Byung Young; Lee, Jung Eun; Lee, Hyun Koo; Jung, Seunbg Hwan; Kim, Byung Woo; Kim, Hyeog Ju; Kim, Dong Sup

    2009-01-01

    entrance surface dose that patients receive during the pelvis and lumbar spine radiography show the following results: in the posteroanterior view of pelvis radiography, the minimum value is 0.59 mGy, the maximum value is 12.69 mGy and the average value is 2.88 mGy with the 1st quartile value being 1.91 mGy, the median being 0.59 mGy, and the 3rd quartile value being 3.43 mGy. Also, in the posteroanterior view of lumbar spine radiography, the minimum value is 0.64 mGy, the maximum value is 23.84 mGy, and the average value is 3.68 mGy with the 1st quartile value being 2.41 mGy, the median being 3.40 mGy, and the 3rd quartile value being 4.08 mGy. In the lateral view of lumbar spine radiography, the minimum value is 1.90 mGy, the maximum value is 45.42 mGy, and the average value is 10.08 mGy with the 1st quartile value being 6.03 mGy, the median being 9.09 mGy and the 3rd quartile value being 12.65 mGy. The diagnostic reference levels for patient radiation dose to be recommended to the medical institutes in Korea is 3.42 mGy for the posteroanterior view of pelvis radiography, 4.08 mGy for the posteroanterior view of lumbar spine radiography, and 12.65 mGy for the lateral view of lumbar spine radiography. Such values are all lower than the values recommended by 6 international organizations including World Health Organization, where the recommended values are 10 mGy for the posteroanterior view of pelvis radiography, 10 mGy for the posteroanterior view of lumbar spine radiography and 30 mGy for the lateral view of lumbar spine radiography.

  17. Evaluation of an exposed-radiation dose on a dual-source cardiac computed tomography examination with a prospective electrocardiogram-gated fast dual spiral scan

    International Nuclear Information System (INIS)

    Matsubara, Kosuke; Koshida, Kichiro; Koshida, Haruka; Sakuta, Keita; Hayashi, Hiroyuki; Takata, Tadanori; Horii, Junsei; Kawai, Keiichi; Yamamoto, Tomoyuki

    2012-01-01

    We evaluated exposed-radiation doses on dual-source cardiac computed tomography (CT) examinations with prospective electrocardiogram (ECG)-gated fast dual spiral scans. After placing dosimeters at locations corresponding to each of the thoracic organs, prospective ECG-gated fast dual spirals and retrospective ECG-gated dual spiral scans were performed to measure the absorbed dose of each organ. In the prospective ECG-gated fast dual spiral scans, the average absorbed doses were 5.03 mGy for the breast, 9.96 mGy for the heart, 6.60 mGy for the lung, 6.48 mGy for the bone marrow, 9.73 mGy for the thymus, and 4.58 mGy for the skin. These values were about 5% of the absorbed doses for the retrospective ECG-gated dual spiral scan. However, the absorbed dose differed greatly at each scan, especially in the external organs such as the breast. For effective and safe use of the prospective ECG-gated fast dual spiral scan, it is necessary to understand these characteristics sufficiently. (author)

  18. Correlation of patient maximum skin doses in cardiac procedures with various dose indicators

    International Nuclear Information System (INIS)

    Domienik, J.; Papierz, S.; Jankowski, J.; Peruga, J.Z.; Werduch, A.; Religa, W.

    2008-01-01

    In most countries of European Union, legislation requires the determination of the total skin dose received by patients during interventional procedures in order to prevent deterministic damages. Various dose indicators like dose-area product (DAP), cumulative dose (CD) and entrance dose at the patient plane (EFD) are used for patient dosimetry purposes in clinical practice. This study aimed at relating those dose indicators with doses ascribed to the most irradiated areas of the patient skin usually expressed in terms of local maximal skin dose (MSD). The study was performed in two different facilities for two most common cardiac procedures coronary angiography (CA) and percutaneous coronary interventions (PCI). For CA procedures, the registered values of fluoroscopy time, total DAP and MSD were in the range (0.7-27.3) min, (16-317) Gy cm 2 and (43-1507) mGy, respectively, and for interventions, accordingly (2.1-43.6) min, (17-425) Gy cm 2 , (71-1555) mGy. Moreover, for CA procedures, CD and EFD were in the ranges (295-4689) mGy and (121-1768) mGy and for PCI (267-6524) mGy and (68-2279) mGy, respectively. No general and satisfactory correlation was found for safe estimation of MSD. However, results show that the best dose indicator which might serve for rough, preliminary estimation is DAP value. In the study, the appropriate trigger levels were proposed for both facilities. (authors)

  19. Radiation pretreatments of cellulose materials for the enhancement of enzymatic hydrolysis

    International Nuclear Information System (INIS)

    Ait Si Mamar, S.; Hadjadj, A.

    1990-01-01

    The conversion of wheat straw agricultural cellulosic wastes to reducing sugars and glucose has been studied by pretreatments by acid hydrolysis and gamma radiolysis over the dose 0-2 MGy. The pretreatment of cellulosic wastes by gamma radiolysis in the presence of sulfuric acid solution shows that the reducing sugars yield increases with the irradiation dose. The effect of radiation degradation on cellulosic wastes between 0.1 MGy and 2 MGy shows the glucose and reducing sugars yields after enzymatic hydrolysis by cellulase vary with the dose. In the relatively low dose range, up to about 0.5 MGy, the reducing sugars yields vary slightly. For an acid hydrolysis followed by radiation at dose range below 0.5 MGy the reducing sugars yields are practically insensitive to radiation. On the other hand, the pretreatment by radiation in higher dose range from 0.5 to 2 MGy followed by enzymatic hydrolysis is effective for the conversion of cellulosic wastes into glucose. The radiation induced degradation of cellulose into glucose depends on the type of acid hydrolysis and on the enzymatic hydrolysis time by cellulase. Pre-irradiation in air is more effective than in acid solution. (author)

  20. Radiation pretreatments of cellulose materials for the enhancement of enzymatic hydrolysis

    Science.gov (United States)

    Mamar, S. Ait Si; Hadjadj, A.

    The conversion of wheat straw agricultural cellulosic wastes to reduning sugars and glucose has been studied by pretreatments by acid hydrolysis and gamma radiolysis over the dose 0-2 MGy. The pretreatment of cellulosic wastes by gamma radiolysis in the presence of sulfuric acid solution shows that the reducing sugars yield increases with the irradiation dose. The effect of radiation degradation on cellulosic wastes between 0.1 MGy and 2 MGy shows the glucose and reducing sugars yields after enzymatic hydrolysis by cellulase vary with the dose. In the relatively low dose range, up to about 0.5 MGy, the reducing sugars yields vary slightly. For an acid hydrolysis followed by radiation at dose range below 0.5 MGy the reducing sugars yields are practically insensitive to radiation. On the other hand, the pretreatment by radiation in higher dose range from 0.5 to 2 MGy followed by enzymatic hydrolysis is effective for the conversion of cellulosic wastes into glucose. The radiation induced degradation of cellulose into glucose depends on the type of acid hydrolysis and on the enzymatic hydrolysis time by cellulase. Pre-irradiation in air is more effective than in acid solution.

  1. Radiation and mental retardation

    International Nuclear Information System (INIS)

    Pochin, E.E.

    1988-01-01

    The editorial comments on a report published by the Radiation Effects Research Foundation in Hiroshima updating information on the induction of mental changes in the light of the revised and more detailed estimate of doses of radiation during pregnancies received by those exposed at Hiroshima and Nagasaki. The estimated risks are little changed. The likelihood of a threshold for exposure during the 16th to 25th week is confirmed-at 700 mGy (with a lower 95% confidence interval of 200 mGy). For the more sensitive time between the eighth to 15th weeks a linear model with no threshold still gives a statistically adequate fit to the data. Now, however, if linear models are tested without the constraint of postulating a threshold of zero, fits are obtained indicating substantial thresholds below which mental retardation would not result. When data on all children are included the maximum likelihood threshold value averages about 250 mGy on the different criteria tested (with mean 95% confidence intervals of 0 and 550 mGy). Or if the analyses exclude five children with conditions that themselves sometimes cause mental retardation a threshold of about 400 mGy is indicated (with mean 95% confidence intervals of 150 and 600 mGy). (author)

  2. Impact of Adaptive Statistical Iterative Reconstruction (ASIR) on radiation dose and image quality in aortic dissection studies: a qualitative and quantitative analysis.

    Science.gov (United States)

    Cornfeld, Daniel; Israel, Gary; Detroy, Ezra; Bokhari, Jamal; Mojibian, Hamid

    2011-03-01

    The purpose of the study was to quantify the radiation dose reduction achieved when imaging the aorta using Adaptive Statistical Iterative Reconstruction (ASIR) and to determine if this has an effect on image quality. We retrospectively reviewed 31 CT angiography examinations of the thoracic and abdominal aorta performed with ASIR and 32 consecutive similar examinations performed without ASIR. Volume CT dose index (CTDI(vol)), dose-length product (DLP), aortic enhancement at multiple levels, aorta-to-muscle contrast-to-noise ratio at multiple levels, and subjective image quality were compared between the two groups. The mean CTDI(vol) and DLP were significantly lower for the studies performed with ASIR versus studies without ASIR (15.6 vs 21.5 mGy, with an average difference of 5.8 mGy [95% CI 2.3-9.4 mGy] and 818 vs 1075 mGy × cm with an average difference of -257 mGy × cm [54-460 mGy × cm], respectively). Aortic enhancement, aortic signal-to-noise ratio, and aortic to muscle contrast-to-noise ratio were not different between the two groups. Subjectively, one reviewer preferred the non-ASIR images and one found the images equivalent. Both reviewers believed the images were of diagnostic quality. A 29% decrease in CTDI(vol) and a 20% decrease in DLP were obtained in scans with ASIR compared with scans without ASIR, without a quantitative loss of image quality.

  3. National reference doses for dental cephalometric radiography.

    Science.gov (United States)

    Holroyd, J R

    2011-12-01

    Diagnostic reference levels (DRLs) are an important tool in the optimisation of clinical radiography. Although national DRLs are provided for many diagnostic procedures including dental intra-oral radiography, there are currently no national DRLs set for cephalometric radiography. In the absence of formal national DRLs, the Health Protection Agency (HPA) has previously published National Reference Doses (NRDs) covering a wide range of diagnostic X-ray examinations. The aim of this study was to determine provisional NRDs for cephalometric radiography. Measurements made by the Dental X-ray Protection Service (DXPS) of the HPA, as part of the cephalometric X-ray equipment testing service provided to dentists and dental trade companies throughout the UK, were used to derive provisional NRDs. Dose-area product measurements were made on 42 X-ray sets. Third quartile dose-area product values for adult and child lateral cephalometric radiography were found to be 41 mGy cm² and 25 mGy cm², respectively, with individual measurements ranging from 3 mGy cm² to 108 mGy cm². This report proposes provisional NRDs of 40 mGy cm² and 25 mGy cm² for adult and child lateral cephalometric radiographs, respectively; these doses could be considered by employers when establishing their local DRLs.

  4. Evaluation of pediatrics entrance surface air kerma during chest X-ray examinations in some Khartoum hospitals

    International Nuclear Information System (INIS)

    Mohamed, Hassan Ishag Yahya

    2015-10-01

    The aim of this study was to determine the amount of entrance surface air kerma dose in air that can reflect the amount of the risk that the children, are subjected to. The parameters that are involved in this project are x-ray tube current (mA), exposure time (sec.), and focal skin distance (FSD) in cm. ESAK is calculated using the equation: ESAK=(Output (mGy/mAs) x (100/FSD) 2 X mAs) for different examination of different patients. 65 cases were involved in this study, the results show that the ESAK mean value (0.18±0.07) mGy, (0.06±0.07) mGy, (0.045±0.017) mGy and (0.049±0.013) mGy at the hospitals (IBNIOF Omdurman, police, clinic doctor) respectively. IBNIOF presented the highest ESAK (0.18±0.07) mGy, while it was lowest in police (0.045±0.017) mGy. The estimated ESAK value were within the established international reference dose values and also the values obtained in pervious studies however, variations were observed in ESAK values among hospitals under study which could be due to the differences in exposure parameters used. Also tube output has some effect on obtained ESAK. (author)

  5. Effects of Chronic Low-Dose Radiation on Human Neural Progenitor Cells

    Science.gov (United States)

    Katsura, Mari; Cyou-Nakamine, Hiromasa; Zen, Qin; Zen, Yang; Nansai, Hiroko; Amagasa, Shota; Kanki, Yasuharu; Inoue, Tsuyoshi; Kaneki, Kiyomi; Taguchi, Akashi; Kobayashi, Mika; Kaji, Toshiyuki; Kodama, Tatsuhiko; Miyagawa, Kiyoshi; Wada, Youichiro; Akimitsu, Nobuyoshi; Sone, Hideko

    2016-01-01

    The effects of chronic low-dose radiation on human health have not been well established. Recent studies have revealed that neural progenitor cells are present not only in the fetal brain but also in the adult brain. Since immature cells are generally more radiosensitive, here we investigated the effects of chronic low-dose radiation on cultured human neural progenitor cells (hNPCs) derived from embryonic stem cells. Radiation at low doses of 31, 124 and 496 mGy per 72 h was administered to hNPCs. The effects were estimated by gene expression profiling with microarray analysis as well as morphological analysis. Gene expression was dose-dependently changed by radiation. By thirty-one mGy of radiation, inflammatory pathways involving interferon signaling and cell junctions were altered. DNA repair and cell adhesion molecules were affected by 124 mGy of radiation while DNA synthesis, apoptosis, metabolism, and neural differentiation were all affected by 496 mGy of radiation. These in vitro results suggest that 496 mGy radiation affects the development of neuronal progenitor cells while altered gene expression was observed at a radiation dose lower than 100 mGy. This study would contribute to the elucidation of the clinical and subclinical phenotypes of impaired neuronal development induced by chronic low-dose radiation.

  6. Effective mechanical means of uterine cervix accelerating maturity in pregnant women of first mature age period of different somatotypes

    Directory of Open Access Journals (Sweden)

    Yakovleva О.V.

    2013-03-01

    Full Text Available The purpose is to evaluate the effectiveness of stimulation of delivery in first mature age period of pregnant women mechanically in different somatotypes. Materials and Methods: 658 patients at 38-41 weeks of gestation of the first period of mature age (22-35 years have been considered. Differentiation by somatotypes has been performed by the method of HT Kaarma (1991. All patients of each somatotype have been divided into primiparous (n = 402 and multiparous (n = 256. Preparation for delivery by mechanical means: on the 1 st day it was introduced into the cervical canal for 16 hours, on the 2nd day — Foley catheter for 8-16 hours (before the birth. Results: In multiparous women the application of mechanical preparation of the birth canal has been effective regardless of somatotype. The percentage of operative delivery in mechanical induction has been lower in multiparous women and also not related to somatotype. In nulliparous women of asthenic and normosthenic type greater efficiency of mechanical induction in preparation for delivery has been revealed. In asthenic and pyknictype mechanical induction has been inefficient and therefore has not been recommended for the use. Conclusion: Application of mechanical means of stimulation of delivery in nulliparous pregnant women should be performed according to their somatotype.

  7. SU-F-I-46: Optimizing Dose Reduction in Adult Head CT Protocols While Maintaining Image Quality in Postmortem Head Scans

    International Nuclear Information System (INIS)

    Lipnharski, I; Carranza, C; Quails, N; Correa, N; Rajderkar, D; Bennett, J; Rill, L; Arreola, M

    2016-01-01

    Purpose: To optimize adult head CT protocol by reducing dose to an appropriate level while providing CT images of diagnostic quality. Methods: Five cadavers were scanned from the skull base to the vertex using a routine adult head CT protocol (120 kVp, 270 mA, 0.75 s rotation, 0.5 mm × 32 detectors, 70.8 mGy CTDIvol) followed by seven reduced-dose protocols with varying combinations of reduced tube current, reduced rotation time, and increased detectors with CTDIvol ranging from 38.2 to 65.6 mGy. Organ doses were directly measured with 21 OSL dosimeters placed on the surface and implanted in the head by a neurosurgeon. Two neuroradiologists assessed grey-white matter differentiation, fluid space, ventricular size, midline shift, brain mass, edema, ischemia, and skull fractures on a three point scale: (1) Unacceptable, (2) Borderline Acceptable, and (3) Acceptable. Results: For the standard scan, doses to the skin, lens of the eye, salivary glands, thyroid, and brain were 37.55 mGy, 49.65 mGy, 40.67 mGy, 4.63 mGy, and 27.33 mGy, respectively. Two cadavers had cerebral edema due to changing dynamics of postmortem effects, causing the grey-white matter differentiation to appear less distinct. Two cadavers with preserved grey-white matter received acceptable scores for all image quality features for the protocol with a CTDIvol of 57.3 mGy, allowing organ dose savings ranging from 34% to 45%. One cadaver allowed for greater dose reduction for the protocol with a CTDIvol of 42 mGy. Conclusion: Efforts to optimize scan protocol should consider both dose and clinical image quality. This is made possible with postmortem subjects, whose brains are similar to patients, allowing for an investigation of ideal scan parameters. Radiologists at our institution accepted scan protocols acquired with lower scan parameters, with CTDIvol values closer to the American College of Radiology’s (ACR) Achievable Dose level of 57 mGy.

  8. SU-F-I-46: Optimizing Dose Reduction in Adult Head CT Protocols While Maintaining Image Quality in Postmortem Head Scans

    Energy Technology Data Exchange (ETDEWEB)

    Lipnharski, I; Carranza, C; Quails, N; Correa, N; Rajderkar, D; Bennett, J; Rill, L; Arreola, M [University of Florida, Gainesville, FL (United States)

    2016-06-15

    Purpose: To optimize adult head CT protocol by reducing dose to an appropriate level while providing CT images of diagnostic quality. Methods: Five cadavers were scanned from the skull base to the vertex using a routine adult head CT protocol (120 kVp, 270 mA, 0.75 s rotation, 0.5 mm × 32 detectors, 70.8 mGy CTDIvol) followed by seven reduced-dose protocols with varying combinations of reduced tube current, reduced rotation time, and increased detectors with CTDIvol ranging from 38.2 to 65.6 mGy. Organ doses were directly measured with 21 OSL dosimeters placed on the surface and implanted in the head by a neurosurgeon. Two neuroradiologists assessed grey-white matter differentiation, fluid space, ventricular size, midline shift, brain mass, edema, ischemia, and skull fractures on a three point scale: (1) Unacceptable, (2) Borderline Acceptable, and (3) Acceptable. Results: For the standard scan, doses to the skin, lens of the eye, salivary glands, thyroid, and brain were 37.55 mGy, 49.65 mGy, 40.67 mGy, 4.63 mGy, and 27.33 mGy, respectively. Two cadavers had cerebral edema due to changing dynamics of postmortem effects, causing the grey-white matter differentiation to appear less distinct. Two cadavers with preserved grey-white matter received acceptable scores for all image quality features for the protocol with a CTDIvol of 57.3 mGy, allowing organ dose savings ranging from 34% to 45%. One cadaver allowed for greater dose reduction for the protocol with a CTDIvol of 42 mGy. Conclusion: Efforts to optimize scan protocol should consider both dose and clinical image quality. This is made possible with postmortem subjects, whose brains are similar to patients, allowing for an investigation of ideal scan parameters. Radiologists at our institution accepted scan protocols acquired with lower scan parameters, with CTDIvol values closer to the American College of Radiology’s (ACR) Achievable Dose level of 57 mGy.

  9. Evaluation of radiation dose during the percutaneous angioplasty for arteriovenous shunt assembling

    International Nuclear Information System (INIS)

    Ting, Chien-Yi; Wu, Wen-Shiann; Tang, Kuo-Ting; Wang, Hsin-Ell; Lin, Chun-Chih

    2017-01-01

    Percutaneous angioplasty (PTA) for dysfunctional hemodialysis is usually performed by radiologists, but not cardiologists, in Taiwan, so that the radiation dose in patients and physicians are usually unknown and related studies are rare. In this study, we are pioneering an investigation into the radiation dose in percutaneous angioplasty for arteriovenous shunt assembling and the effect of RADPAD device, a lead-free surgical drape containing Bi and Ba, on the decrease of a radiation dose in the non-targeted organs of the patient and also the operator. The radiation dose in a typical digital subtraction angiography (DSA) by the PTA protocol under a fixed field of view (FOV), was measured with optically simulated luminescent dosimeters arranged in a PIXY RS-102 anthropomorphic phantom. The results indicate that there is a significant dose reduction at the hands (0.022±0.002 mGy before treatment vs. 0.014±0.001 mGy after treatment; P=0.021), but not at the lens (0.027±0.003 mGy before treatment vs. 0.018±0.001 mGy after treatment; P=0.058), and the gonads (0.026±0.003 mGy before treatment vs. 0.020±0.001 mGy after treatment; P=0.058), of the cardiologist/operator after treatment with the RADPAD drape. At the patient's abdomen, the dose significantly decreased from 1.597±0.104 mGy to 0.031±0.002 mGy (P<0.001) after treated with the RADPAD shield. For the chest, lens and thyroid in the patient, the doses were respectively 0.154±0.100 mGy (compared to 0.049±0.001 mGy after treated with the RADPAD drape; P=0.0002), 0.066±0.001 mGy (compared to 0.021±0.001 mGy after the RADPAD treatment; P=0.009), and 0.208±0.002 mGy (compared to 0.042±0.003 mGy after shielded with the RADPAD drape; P<0.0001), which represents an apparent reduction in dose. However, no significant difference was found in the dose-area product between before (179.9±0.1mGy.cm 2 ) and after (177.4±0.1mGy.cm 2 ) the treatment (P=0.38). In conclusion, the RADPAD drape significantly reduced

  10. Determining and managing fetal radiation dose from diagnostic radiology procedures in Turkey

    International Nuclear Information System (INIS)

    Ozbayrak, Mustafa; Cavdar, Iffet; Seven, Mehmet; Uslu, Lebriz; Yeyin, Nami; Tanyildizi, Handan; Abuqbeitah, Mohammad; Acikgoz, A. Serdar; Tuten, Abdullah; Demir, Mustafa

    2015-01-01

    We intended to calculate approximate fetal doses in pregnant women who underwent diagnostic radiology procedures and to evaluate the safety of their pregnancies. We contacted hospitals in different cities in Turkey where requests for fetal dose calculation are usually sent. Fetal radiation exposure was calculated for 304 cases in 218 pregnant women with gestational ages ranging from 5 days to 19 weeks, 2 days. FetDose software (ver. 4.0) was used in fetal dose calculations for radiographic and computed tomography (CT) procedures. The body was divided into three zones according to distance from the fetus. The first zone consisted of the head area, the lower extremities below the knee, and the upper extremities; the second consisted of the cervicothoracic region and upper thighs; and the third consisted of the abdominopelvic area. Fetal doses from radiologic procedures between zones were compared using the Kruskal-Wallis test and a Bonferroni-corrected Mann-Whitney U-test. The average fetal doses from radiography and CT in the first zone were 0.05 ± 0.01 mGy and 0.81 ± 0.04 mGy, respectively; 0.21 ± 0.05 mGy and 1.77 ± 0.22 mGy, respectively, in the second zone; and 6.42 ± 0.82 mGy and 22.94 ± 1.28 mGy, respectively, in the third zone (p < 0.001). Our results showed that fetal radiation exposures in our group of pregnant women did not reach the level (50 mGy) that is known to increase risk for congenital anomalies. Fetal radiation exposure in the diagnostic radiology procedures in our study did not reach risk levels that might have indicated abortion

  11. Cultural differences in postnatal quality of life among German-speaking women - a prospective survey in two countries.

    Science.gov (United States)

    Grylka-Baeschlin, Susanne; van Teijlingen, Edwin; Gross, Mechthild M

    2014-08-15

    Assessment of quality of life after childbirth is an important health-outcome measurement for new mothers and is of special interest in midwifery. The Mother-Generated Index (MGI) is a validated instrument to assess postnatal quality of life. The tool has not been applied for making a cross-cultural comparison before. This study investigated (a) responses to the MGI in German-speaking women in Germany and Switzerland; and (b) associations between MGI scores on the one hand and maternity and midwifery care on the other. A two-stage survey was conducted in two rural hospitals 10 km apart, on opposite sides of the German-Swiss border. The questionnaires included the MGI and questions on socio-demographics, physical and mental health and maternity care, and were distributed during the first days after birth and six weeks postpartum. Parametric and non-parametric tests were computed with the statistical programme SPSS. A total of 129 questionnaires were returned an average of three days after birth and 83 in the follow-up after seven weeks. There were no statistically significant differences in the MGI scores between the German and the Swiss women (p = 0.22). Significantly more favourable MGI scores were found associated with more adequate information during pregnancy (p = 0.02), a more satisfactory birth experience (p German-speaking women were higher than those in other studies reported previously. Thus the tool may be able to detect differences in postnatal quality of life among women with substantially divergent cultural backgrounds. Shortcomings in maternity and midwifery care were detected, as for example the inadequate provision of information during pregnancy, a lack of individualised postpartum care during the hospital stay and insufficient support for exclusively breastfeeding mothers. The MGI is an appropriate instrument for maternity care outcome measurement in cross-cultural comparison research.

  12. Assessment of Patients’ Entrance Skin Dose from Diagnostic X-ray Examinations at Public Hospitals of Akwa Ibom State, Nigeria

    Directory of Open Access Journals (Sweden)

    Esen Nsikan U

    2015-07-01

    Full Text Available Introduction High doses of ionizing radiation can lead to adverse health outcomes such as cancer induction in humans. Although the consequences are less evident at very low radiation doses, the associated risks are of societal importance. This study aimed at assessing entrance skin doses (ESDs in patients undergoing selected diagnostic X-ray examinations at public hospitals of Akwa Ibom State, Nigeria. Materials and Methods In total, six examinations were performed on 720 patients in this study.   CALDose_X5 software program was used in estimating ESDs based on patients’ information and technical exposure parameters. Results The estimated ESDs ranged from 0.59 to 0.61 mGy for PA and RLAT projections of the thorax, respectively. ESDs for the AP and RLAT projections of the cranium were 1.65 and 1.48 mGy, respectively. Also, ESD values for the AP view of the abdomen and pelvis were 1.89 and 1.88 mGy, respectively. The mean effective dose was within the range of 0.021-0.075 mGy for the thorax (mean= 0.037, 0.008-0.045 mGy for the cranium (mean= 0.016, 0.215-0.225 mGy for the abdomen (mean= 0.219 and 0.101-0.119 mGy for the pelvis (mean= 0.112. Conclusion The obtained results were comparable to the international reference dose levels, except for the PA projection of the thorax. Therefore, quality assurance programs are required in diagnostic X-ray units of Nigeria hospitals. The obtained findings add to the available data and can help authorities establish reference dose levels for diagnostic radiography in Nigeria.

  13. The long-term effects of acute exposure to ionising radiation on survival and fertility in Daphnia magna

    International Nuclear Information System (INIS)

    Sarapultseva, Elena I.; Dubrova, Yuri E.

    2016-01-01

    The results of recent studies have provided strong evidence for the transgenerational effects of parental exposure to ionising radiation and chemical mutagens. However, the transgenerational effects of parental exposure on survival and fertility remain poorly understood. To establish whether parental irradiation can affect the survival and fertility of directly exposed organisms and their offspring, crustacean Daphnia magna were given 10, 100, 1000 and 10,000 mGy of acute γ-rays. Exposure to 1000 and 10,000 mGy significantly compromised the viability of irradiated Daphnia and their first-generation progeny, but did not affect the second-generation progeny. The fertility of F 0 and F 1 Daphnia gradually declined with the dose of parental exposure and significantly decreased at dose of 100 mGy and at higher doses. The effects of parental irradiation on the number of broods were only observed among the F 0 Daphnia exposed to 1000 and 10,000 mGy, whereas the brood size was equally affected in the two consecutive generations. In contrast, the F 2 total fertility was compromised only among progeny of parents that received the highest dose of 10,000 mGy. We propose that the decreased fertility observed among the F 2 progeny of parents exposed to 10,000 mGy is attributed to transgenerational effects of parental irradiation. Our results also indicate a substantial recovery of the F 2 progeny of irradiated F 0 Daphnia exposed to the lower doses of acute γ-rays. - Highlights: • Viability of irradiated daphnids and their F 1 progeny is compromised. • Viability of the F 2 progeny of irradiated parents is not affected. • Total fertility of irradiated daphnids and their F 1 progeny declines with the dose. • Total fertility of the F 2 progeny of parents exposed to 10,000 mGy is compromised. • The decreased fertility among the F 2 progeny is transgenerational phenomenon.

  14. Determining and managing fetal radiation dose from diagnostic radiology procedures in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Ozbayrak, Mustafa; Cavdar, Iffet; Seven, Mehmet; Uslu, Lebriz; Yeyin, Nami; Tanyildizi, Handan; Abuqbeitah, Mohammad; Acikgoz, A. Serdar; Tuten, Abdullah; Demir, Mustafa [Istanbul University, Istanbul (Turkmenistan)

    2015-12-15

    We intended to calculate approximate fetal doses in pregnant women who underwent diagnostic radiology procedures and to evaluate the safety of their pregnancies. We contacted hospitals in different cities in Turkey where requests for fetal dose calculation are usually sent. Fetal radiation exposure was calculated for 304 cases in 218 pregnant women with gestational ages ranging from 5 days to 19 weeks, 2 days. FetDose software (ver. 4.0) was used in fetal dose calculations for radiographic and computed tomography (CT) procedures. The body was divided into three zones according to distance from the fetus. The first zone consisted of the head area, the lower extremities below the knee, and the upper extremities; the second consisted of the cervicothoracic region and upper thighs; and the third consisted of the abdominopelvic area. Fetal doses from radiologic procedures between zones were compared using the Kruskal-Wallis test and a Bonferroni-corrected Mann-Whitney U-test. The average fetal doses from radiography and CT in the first zone were 0.05 ± 0.01 mGy and 0.81 ± 0.04 mGy, respectively; 0.21 ± 0.05 mGy and 1.77 ± 0.22 mGy, respectively, in the second zone; and 6.42 ± 0.82 mGy and 22.94 ± 1.28 mGy, respectively, in the third zone (p < 0.001). Our results showed that fetal radiation exposures in our group of pregnant women did not reach the level (50 mGy) that is known to increase risk for congenital anomalies. Fetal radiation exposure in the diagnostic radiology procedures in our study did not reach risk levels that might have indicated abortion.

  15. Electron beam irradiation effects on carbon fiber reinforced PEEK composite

    International Nuclear Information System (INIS)

    Sasuga, Tsuneo; Hagiwara, Miyuki; Odajima, Tosikazu; Sakai, Hideo; Nakakura, Toshiyuki; Masutani, Masahiro.

    1987-03-01

    Carbon fiber(CF) reinforced composites, using polyarylether-sulfone (PES) or polyarylether-ether-ketone (PEEK) as matrix material, were prepared and their electron beam irradiation effects were studied on the basis of changes in mechanical and dynamic viscoelastic properties and observation of fracture surfaces. The flexural strength of PES-CF composite decreased to 70 % of the initial strength after the irradiation of 3 MGy and 40 % after 15 MGy. The change in the profile of stress-strain (S-S) curves and fractographic observation by electron microscopy indicated that this composite irradiated with over 3 MGy was fractured by delamination caused by to the degradation of matrix polymer. The mechanical properties of PEEK-CF composite were scarcely decreased even after irradiated up to 180 MGy and this composite showed very high radiation resistance. The change in the profile of S-S curves and fractographic observation showed that this composite fractured due to destruction of fiber in the dose range less than 180 MGy, indicating that PEEK was excellent matrix material used in high radiation field. PEEK-PES-CF composite which was composed of the carbon fibers coated with PES solution showed less radiation resistance compared with PEEK-CF composite; the flexural strength decreased to 85 % of the initial value after the irradiation with 90 MGy. It was revealed from the changes in the profile of S-S curve that the specimen irradiated over 120 MGy was fractured due to not only fiber destruction but delamination. Deterioration mechanism of PEEK-PES-CF composite was studied by dynamic viscoelastic measurements in connection with the damage on matrix-fiber interface. It was suggested that the deterioration in mechanical properties of this composite was caused by the degradation of PES that coated on the surface of the carbon fibers. (author)

  16. Dose response relationship for unstable-type chromosome aberration rate of spleen cells from mice continuously exposed to low-dose-rate gamma-rays

    International Nuclear Information System (INIS)

    Tanaka, Kimio; Khoda, Atsushi; Ichinohe, Kazuaki; Oghiso, Yoichi

    2007-01-01

    It has been reported that people who are chronically exposed to radiation such as nuclear facility workers and medical radiologists have slightly higher incidences of chromosome aberrations than non-exposed people. However, chronological changes of chromosome aberration rates related to accumulated doses and dose-rates for low dose-rate radiation exposures have not been well studied. Precise analyses of human populations are quite limited because confounding factors influence the results. For this reason, animal experiments are important for analyses. Mice were continuously exposed to gamma-rays at 400 mGy/22 hr/day for 10 days, 20 mGy/22 hr/day for about 400 days, and 1 mGy/22 hr/day for about 615 days under SPF conditions. Chronological changes of unstable-type chromosome aberration rates of spleen cells were observed along with accumulated doses at the middle dose rate and the two low-dose rates by conventional Giemsa-staining method. Aberrations such as dicentric chromosome, ring chromosome and fragment increased in a two-phase manner within 0-1.2 Gy and 2-8 Gy at 20 mGy/22 hr/day. They slightly increased up to 0.5 Gy at 1 mGy/22 hr/day. Aberration rates for 1, 2, 8 Gy at the 20 mGy/22 hr/day and for 0.5 Gy at 1 mGy/22 hr/day were 5.1, 9.6, 13.9 and 2.2 times higher than those of age-matched, non-irradiated control mice, respectively. Chromosome aberration rates at 400 mGy/22 hr/day were 2.7 times higher than that of 20 mGy/22 hr/day for the same total dose of 1.2 Gy. The results that unstable-type chromosome aberrations increased with accumulated dose of the low-dose rate radiation will be important to establish biological dosimetry for people who are chronically exposed to radiation. (author)

  17. Photon hormesis deactivates alpha-particle induced bystander effects between zebrafish embryos

    International Nuclear Information System (INIS)

    Ng, C.Y.P.; Cheng, S.H.; Yu, K.N.

    2017-01-01

    In the present work, we studied the effects of low-dose X-ray photons on the alpha-particle induced bystander effects between embryos of the zebrafish, Danio rerio. The effects on the naive whole embryos were studied through quantification of apoptotic signals (amounts of cells undergoing apoptosis) at 24 h post fertilization (hpf) using vital dye acridine orange staining, followed by counting the stained cells under a fluorescent microscope. We report data showing that embryos at 5 hpf subjected to a 4.4 mGy alpha-particle irradiation could release a stress signal into the medium, which could induce bystander effect in partnered naive embryos sharing the same medium. We also report that the bystander effect was deactivated when the irradiated embryos were subjected to a concomitant irradiation of 10 or 14 mGy of X-rays, but no such deactivation was achieved if the concomitant X-ray dose dropped to 2.5 or 5 mGy. In the present study, the significant drop in the amount of apoptotic signals on the embryos having received 4.4 mGy alpha particles together X-rays irradiation from 2.5 or 5 mGy to 10 or 14 mGy, together with the deactivation of RIBE with concomitant irradiation of 10 or 14 mGy of X-rays supported the participation of photon hormesis with an onset dose between 5 and 10 mGy, which might lead to removal of aberrant cells through early apoptosis or induction of high-fidelity DNA repair. As we found that photons and alpha particles could have opposite biological effects when these were simultaneously irradiated onto living organisms, these ionizing radiations could be viewed as two different environmental stressors, and the resultant effects could be regarded as multiple stressor effects. The present work presented the first study on a multiple stressor effect which occurred on bystander organisms. In other words, this was a non-targeted multiple stressor effect. The photon hormesis could also explain some failed attempts to observe neutron-induced bystander

  18. Radiation induced micrencephaly in guinea pigs

    International Nuclear Information System (INIS)

    Wagner, L.K.; Johnston, D.A.; Felleman, D.J.

    1991-01-01

    A brain weight deficit of about 70 mg was induced at doses of approximately 75-mGy and a deficit of 60 mg was induced at 100 mGy. This confirms the effects projected and observed by Wanner and Edwards. Although the data do not demonstrate a clear dose-response relationship between the 75-mGy and 100-mGy groups, the data are statistically consistent with a dose-response effect because of the overlapping confidence intervals. The lack of a statistically significant observation is most likely related to the small difference in doses and the limited numbers of animals examined. There are several factors that can influence the brain weight of guinea pig pups, such as caging and housing conditions, the sex of the animal, and litter size. These should be taken into account for accurate analysis. Dam weight did not appear to have a significant effect. The confirmation of a micrencephalic effect induced x rays at doses of 75-mGy during this late embryonic stage of development is consistent with the findings of small head size induced in those exposed prior to the eight week of conception at Hiroshima. This implies a mechanism for micrencephaly different from those previously suggested and lends credence to a causal relation between radiation and small head size in humans at low doses as reported by Miller and Mulvihill. 16 refs., 13 tabs

  19. The 3rd international intercomparison on EPR tooth dosimetry: Part 1, general analysis

    International Nuclear Information System (INIS)

    Wieser, A.; Debuyst, R.; Fattibene, P.

    2005-01-01

    The objective of the 3rd International Intercomparison on Electron Paramagnetic Resonance (EPR) Tooth Dosimetry was the evaluation of laboratories performing tooth enamel dosimetry below 300 mGy. Participants had to reconstruct the absorbed dose in tooth enamel from 11 molars, which were cut into two halves. One half of each tooth was irradiated in a 60 Co beam to doses in the ranges of 30-100 mGy (5 samples), 100-300 mGy (5 samples), and 300-900 mGy (1 sample). Fourteen international laboratories participated in this intercomparison programme. A first analysis of the results and an overview of the essential features of methods applied in different laboratories are presented. The relative standard deviation of results of all methods was better than 27% for applied doses in the range of 79-704 mGy. In the analysis of the unirradiated tooth halves 8% of the samples were identified as outliers with additional absorbed dose above background dose

  20. Clinical indications and radiation doses to the conceptus associated with CT imaging in pregnancy: a retrospective study

    Energy Technology Data Exchange (ETDEWEB)

    Woussen, S.; Vanbeckevoort, D.; Bosmans, H.; Oyen, R. [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Lopez-Rendon, X.; Zanca, F. [University Hospitals Leuven, Department of Imaging and Pathology, Leuven (Belgium)

    2016-04-15

    To perform an internal audit at a university hospital with the aim of evaluating the number, clinical indication and operating procedure of computed tomography (CT) performed on pregnant patients and of estimating the radiation doses to the conceptus. A retrospective review was conducted of all CT examinations performed in a single centre on pregnant patients between January 2008 and July 2013. The radiation doses to the conceptus were estimated. The results were compared with published data. The number of CT examinations during pregnancy increased from 3-4 per year in 2008-2011 to 11 per year in 2012. The mean estimated conceptus radiation dose was considered negligible for CT of the head and cervical spine, being less than 0.01 mGy, and for CT of the chest, less than 0.1 mGy. The estimated conceptus radiation dose from abdominopelvic CT was on average 28.7 mGy (range 6.7-60.5 mGy). The number of CT scans of pregnant patients increased threefold during the last few years. Most clinical indications and doses were in line with good clinical practice and literature; only in two cases the dose to the conceptus was higher than 50 mGy. (orig.)

  1. Patient dosimetry study of a paediatric CT examination

    International Nuclear Information System (INIS)

    Hranitzky, C.; Stadtmann, H.

    2011-01-01

    Dosimetry studies are of increasing interest in diagnostic high-dose applications such as computed tomography especially for examinations of children. A routine CT scan protocol for paediatric head and neck imaging was investigated at a new multi-detector CT scanner using LiF:Mg,Cu,P thermoluminescence dosemeters (TLDs) and a 0.125 cm 3 thimble ionization chamber. Calibrations of the detectors in terms of absorbed dose to water were carried out at the Dosimetry Laboratory Seibersdorf in standard radiation fields. The dosimetry method was validated in the spiral CT X-ray field by comparing TLD and ionization chamber measurement results in cylindrical PMMA phantoms. Absorbed dose results were within stated uncertainties. An anthropomorphic phantom representing a child of about 5 years was loaded with TLD chips at various organ and tissue positions in the head and neck region as well as at some critical organ locations. Organ dose values were calculated from TLD based average absorbed dose with about 5% total uncertainty, e.g. 22 mGy (eyes), 21 mGy (thyroid), 19 mGy (brain), 3.4 mGy (thymus), and 0.03 mGy (testes). For comparison purposes an effective dose of 1.9 mSv was estimated for the investigated paediatric CT examination based on ICRP-103 age-independent tissue-weighting factors.

  2. Reference dose levels for dental panoramic radiography in Anyang City

    International Nuclear Information System (INIS)

    Han, Mi Ra; Kang, Byung Cheol; Yoon, Suk Ja; Lee, Jae Seo; Kim, Young Hee

    2009-01-01

    To measure dose-width product (DWP) values used for dental panoramic radiography in Anyang city, Korea. Thirty-six panoramic dental radiographic sets (17 analogue panoramic sets and 19 digital panoramic sets) in 36 dental clinics in Anyang city were included in the study. Each patient's panoramic exposure parameters were simulated and the panoramic radiation doses were measured at the secondary collimator using a Mult-O-Meter (Unfors Instruments, Billdal, Sweden) at each dental clinic during 2006. The third quartile DWP was determined from 310 surface dose measurements on adult. The third quartile DWP for adult panoramic radiograph was 106.7 mGy mm. For analogue and digital panoramic radiograph, 3/4 DWP were 116.8 mGy mm and 72 mGy mm respectively. The overall third quartile DWP of panoramic radiography was 106.7 mGy mm. The measured 3/4 DWPs were higher than the 3/4 DWP of 65 mGy mm recommended by NRPB. Dentists who are operating above the reference dose should lower their panoramic exposure doses below the recommended reference value by changing the exposure parameters and/or their panoramic equipment.

  3. Environmental effects of radionuclides--observations on natural ecosystems.

    Science.gov (United States)

    Copplestone, D; Toal, M E; Johnson, M S; Jackson, D; Jones, S R

    2000-03-01

    To better quantify risk to non-human species from exposure to environmental radioactivity, understanding of the behaviour of radionuclides in the biosphere needs to be increased. This study outlines current thinking on ecological risk assessment (ERA) methodology and applies the indicator species or critical groups approach to biota inhabiting a semi-natural coniferous woodland contaminated with the radionuclides 137Cs, 238Pu, 239+240Pu and 241Am. The majority of these radionuclides originate from routine aerial emissions from the nuclear fuel reprocessing plant at BNFL, Sellafield, Cumbria, UK. Radionuclide activity concentrations have been determined in biota from the woodland and estimates of absorbed dose rates (mGy d(-1)) have been calculated using the dosimetric models outlined. Dose rates to the key indicator species, Oniscus asellus, Carabus violaceous and Apodemus sylvaticus (detritivorous invertebrate, predatory invertebrate and the granivorous wood mouse) have been determined at 3.0 x 10(-3) mGy d(-1), 2.2 x 10(-3) mGy d(-1) and 1.0 x 10(-3) mGy d(-1) respectively. The values are at least three orders of magnitude lower than the 1 mGy d(-1) level below which no observable effects on populations in a terrestrial ecosystem are thought to occur. Limitations of this approach are discussed.

  4. Diagnostic reference levels in intraoral radiology: From the laboratory to clinical practice

    International Nuclear Information System (INIS)

    Alcaraz, M.; Velasco, E.; Martinez-Beneyto, Y.; Velasco, F.; Parra, C.; Canteras, M.

    2010-01-01

    To determine the diagnostic reference levels (DRLs) for obtaining a diagnostic image in the normal conditions of clinical practice and to explain the differences between the levels found and the DRLs obtained in other experimental conditions, suggesting that there has been a reduction in the European Union (EU) recommended levels. A total of 2296 official reports on dental surgeries from 16 Spanish autonomous regions compiled during 2008 were studied. A mean DRL of 3.3 mGy was determined: 2.6 mGy for installations using direct digital systems, 3.4 mGy for those using indirect systems, 4.4 mGy for those using Ultra-speed film and 3.7 mGy for those using Insight. The DRLs found in this survey are below the EU recommended values but far above previously described values, possibly because all the different systems were considered and because values refer to those of the normal work conditions of clinical practice. (authors)

  5. Environmental effects of radionuclides - observations on natural ecosystems

    International Nuclear Information System (INIS)

    Copplestone, D.; Toal, M.E.; Johnson, M.S.; Jackson, D.; Jones, S.R.

    2000-01-01

    To better quantify risk to non-human species from exposure to environmental radioactivity, understanding of the behaviour of radionuclides in the biosphere needs to be increased. This study outlines current thinking on ecological risk assessment (ERA) methodology and applies the indicator species or critical groups approach to biota inhabiting a semi-natural coniferous woodland contaminated with the radionuclides 137 Cs, 238 Pu, 239+240 Pu and 241 Am. The majority of these radionuclides originate from routine aerial emissions from the nuclear fuel reprocessing plant at BNFL, Sellafield, Cumbria, UK. Radionuclide activity concentrations have been determined in biota from the woodland and estimates of absorbed dose rates (mGy d -1 ) have been calculated using the dosimetric models outlined. Dose rates to the key indicator species, Oniscus asellus, Carabus violaceous and Apodemus sylvaticus (detritivorous invertebrate, predatory invertebrate and the granivorous wood mouse) have been determined at 3.0x10 -3 mGy d -1 , 2.2x10 -3 mGy d -1 and 1.0x10 -3 mGy d -1 respectively. The values are at least three orders of magnitude lower than the 1 mGy d -1 level below which no observable effects on populations in a terrestrial ecosystem are thought to occur. Limitations of this approach are discussed. (author)

  6. Imaging lobular breast carcinoma: comparison of synchrotron radiation DEI-CT technique with clinical CT, mammography and histology

    Science.gov (United States)

    Fiedler, S.; Bravin, A.; Keyriläinen, J.; Fernández, M.; Suortti, P.; Thomlinson, W.; Tenhunen, M.; Virkkunen, P.; Karjalainen-Lindsberg, M.-L.

    2004-01-01

    Different modalities for imaging cancer-bearing breast tissue samples are described and compared. The images include clinical mammograms and computed tomography (CT) images, CT images with partly coherent synchrotron radiation (SR), and CT and radiography images taken with SR using the diffraction enhanced imaging (DEI) method. The images are evaluated by a radiologist and compared with histopathological examination of the samples. Two cases of lobular carcinoma are studied in detail. The indications of cancer are very weak or invisible in the conventional images, but the morphological changes due to invasion of cancer become pronounced in the images taken by the DEI method. The strands penetrating adipose tissue are seen clearly in the DEI-CT images, and the histopathology confirms that some strands contain the so-called 'Indian file' formations of cancer cells. The radiation dose is carefully measured for each of the imaging modalities. The mean glandular dose (MGD) for 50% glandular breast tissue is about 1 mGy in conventional mammography and less than 0.25 mGy in projection DEI, while in the clinical CT imaging the MGD is very high, about 45 mGy. The entrance dose of 95 mGy in DEI-CT imaging gives rise to an MGD of 40 mGy, but the dose may be reduced by an order of magnitude, because the contrast is very large in most images.

  7. Increased apoptosis and DNA double-strand breaks in the embryonic mouse brain in response to very low-dose X-rays but not 50 Hz magnetic fields

    Science.gov (United States)

    Saha, Shreya; Woodbine, Lisa; Haines, Jackie; Coster, Margaret; Ricket, Nicole; Barazzuol, Lara; Ainsbury, Elizabeth; Sienkiewicz, Zenon; Jeggo, Penny

    2014-01-01

    The use of X-rays for medical diagnosis is enhancing exposure to low radiation doses. Exposure to extremely low-frequency electromagnetic or magnetic fields is also increasing. Epidemiological studies show consistent associations of childhood leukaemia with exposure to magnetic fields but any causal relationship is unclear. A limitation in assessing the consequence of such exposure is the availability of sensitive assays. The embryonic neuronal stem and progenitor cell compartments are radiosensitive tissues. Using sensitive assays, we report a statistically significant increase in DNA double-strand break (DSB) formation and apoptosis in the embryonic neuronal stem cell compartment following in utero exposure to 10–200 mGy X-rays. Both endpoints show a linear response. We also show that DSB repair is delayed following exposure to doses below 50 mGy compared with 100 mGy. Thus, we demonstrate in vivo consequences of low-dose radiation. In contrast to these impacts, we did not observe any significant induction of DSBs or apoptosis following exposure to 50 Hz magnetic fields (100 or 300 µT). We conclude that any DSB induction by treatment with magnetic fields is lower than following exposure to 10 mGy X-rays. For comparison, certain procedures involving computed tomography scanning are equivalent to 1–5 mGy X-rays. PMID:25209403

  8. Effects of Low Versus Moderate Glycemic Index Diets on Aerobic Capacity in Endurance Runners: Three-Week Randomized Controlled Crossover Trial

    Directory of Open Access Journals (Sweden)

    Krzysztof Durkalec-Michalski

    2018-03-01

    Full Text Available The glycemic index (GI of ingested carbohydrates may influence substrate oxidation during exercise and athletic performance. Therefore, the aim of this study was to assess the effect of low- and moderate-GI three-week diets on aerobic capacity and endurance performance in runners. We conducted a randomized crossover feeding study of matched diets differing only in GI (low vs. moderate in 21 endurance-trained runners. Each participant consumed both, low- (LGI and moderate-GI (MGI high-carbohydrate (~60% and nutrient-balanced diets for three weeks each. At the beginning and end of each diet, participants had their aerobic capacity and body composition measured and performed a 12-min running test. After LGI, time to exhaustion during incremental cycling test (ICT and distance covered in the 12-min run were significantly increased. The MGI diet led to an increase in maximal oxygen uptake ( V ˙ O2max, but no performance benefits were found after the MGI diet. The LGI and MGI diets improved time and workload at gas exchange threshold (GET during ICT. The results indicate that a three-week high-carbohydrate LGI diet resulted in a small but significant improvement in athletic performance in endurance runners. Observed increase in V ˙ O2max on MGI diet did not affect performance.

  9. Environmental effects of radionuclides - observations on natural ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Copplestone, D. [Industrial Ecology Research Centre, School of Biological Sciences, University of Liverpool, Liverpool L69 3BX (United Kingdom). E-mail: copplest at liv.ac.uk; Toal, M.E.; Johnson, M.S. [Industrial Ecology Research Centre, School of Biological Sciences, University of Liverpool, Liverpool L69 3BX (United Kingdom); Jackson, D.; Jones, S.R. [Westlakes Scientific Consulting, Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria CA24 3LN (United Kingdom)

    2000-03-01

    To better quantify risk to non-human species from exposure to environmental radioactivity, understanding of the behaviour of radionuclides in the biosphere needs to be increased. This study outlines current thinking on ecological risk assessment (ERA) methodology and applies the indicator species or critical groups approach to biota inhabiting a semi-natural coniferous woodland contaminated with the radionuclides {sup 137}Cs, {sup 238}Pu, {sup 239+240}Pu and {sup 241}Am. The majority of these radionuclides originate from routine aerial emissions from the nuclear fuel reprocessing plant at BNFL, Sellafield, Cumbria, UK. Radionuclide activity concentrations have been determined in biota from the woodland and estimates of absorbed dose rates (mGy d{sup -1}) have been calculated using the dosimetric models outlined. Dose rates to the key indicator species, Oniscus asellus, Carabus violaceous and Apodemus sylvaticus (detritivorous invertebrate, predatory invertebrate and the granivorous wood mouse) have been determined at 3.0x10{sup -3} mGy d{sup -1}, 2.2x10{sup -3} mGy d{sup -1} and 1.0x10{sup -3} mGy d{sup -1} respectively. The values are at least three orders of magnitude lower than the 1 mGy d{sup -1} level below which no observable effects on populations in a terrestrial ecosystem are thought to occur. Limitations of this approach are discussed. (author)

  10. ESR dosimetry study for the residents of Kazakhstan exposed to radioactive fallout on 24, August 1956

    Energy Technology Data Exchange (ETDEWEB)

    Zhumadilov, K., E-mail: kassym@hiroshima-u.ac.jp [Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan); Ivannikov, A. [Medical Radiological Research Center, Obninsk 249036 (Russian Federation); Zharlyganova, D. [Astana Medical University, 51a, Beibitshilik str., Astana 010000 (Kazakhstan); Zhumadilov, Zh. [Nazarbayev University, Life Sciences Center, D. Kunayev str., Astana 010000 (Kazakhstan); Stepanenko, V. [Medical Radiological Research Center, Obninsk 249036 (Russian Federation); Abralina, Sh.; Sadvokasova, L. [Semey State Medical Academy, Semey 071400, Abay str. 103 (Kazakhstan); Zhumadilova, A. [Astana Medical University, 51a, Beibitshilik str., Astana 010000 (Kazakhstan); Toyoda, S. [Department of Applied Physics, Faculty of Science, Okayama University of Science, Okayama 700-0005 (Japan); Endo, S. [Department of Quantum Energy Applications, Graduated School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527 (Japan); Okamoto, T. [Department of Molecular Oral Medicine and Maxillofacial Surgery, Division of Frontier Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima 734-8553 (Japan); Hoshi, M. [Research Institute for Radiation Biology and Medicine, Hiroshima University, Kasumi 1-2-3, Minami-ku, Hiroshima 734-8553 (Japan)

    2011-09-15

    The method of electron spin resonance (ESR) dosimetry has been applied to human tooth enamel in order to obtain individual absorbed doses from the population of settlements within the vicinity of the central axis of the radioactive fallout trace from the contaminating nuclear surface test of 24, August 1956. Most of the settlements (Glubokoe, Tavriya, and Gagarino) are located near Ust-Kamenogorsk city, in Kazakhstan (about 400 km to the east from the epicenter of the explosion at the Semipalatinsk Nuclear Test Site (SNTS)). It was found that the excess doses obtained after the subtraction of natural background radiation ranged up to about 120 mGy for the residents of Ust-Kamenogorsk city, whose tooth enamel was formed before 1956. For the residents of Gagarino, excess doses do not exceed 47 mGy for all ages. For the residents of Tavriya, the maximum of excess dose was determined as 54 mGy and for the residents of Glubokoe, the maximum excess dose was about 83 mGy. For the population of the Shemonaikha settlements (about 70 km from the centerline of the radioactive fallout trace) the highest excess dose is 110 mGy. Also for this study, Znamenka village (about 130 km from the epicenter) was included. The Kokpekty settlement was chosen as a control and not subjected to any radioactive contamination and is located 400 km to the Southeast from SNTS.

  11. Increased apoptosis and DNA double-strand breaks in the embryonic mouse brain in response to very low-dose X-rays but not 50 Hz magnetic fields.

    Science.gov (United States)

    Saha, Shreya; Woodbine, Lisa; Haines, Jackie; Coster, Margaret; Ricket, Nicole; Barazzuol, Lara; Ainsbury, Elizabeth; Sienkiewicz, Zenon; Jeggo, Penny

    2014-11-06

    The use of X-rays for medical diagnosis is enhancing exposure to low radiation doses. Exposure to extremely low-frequency electromagnetic or magnetic fields is also increasing. Epidemiological studies show consistent associations of childhood leukaemia with exposure to magnetic fields but any causal relationship is unclear. A limitation in assessing the consequence of such exposure is the availability of sensitive assays. The embryonic neuronal stem and progenitor cell compartments are radiosensitive tissues. Using sensitive assays, we report a statistically significant increase in DNA double-strand break (DSB) formation and apoptosis in the embryonic neuronal stem cell compartment following in utero exposure to 10-200 mGy X-rays. Both endpoints show a linear response. We also show that DSB repair is delayed following exposure to doses below 50 mGy compared with 100 mGy. Thus, we demonstrate in vivo consequences of low-dose radiation. In contrast to these impacts, we did not observe any significant induction of DSBs or apoptosis following exposure to 50 Hz magnetic fields (100 or 300 µT). We conclude that any DSB induction by treatment with magnetic fields is lower than following exposure to 10 mGy X-rays. For comparison, certain procedures involving computed tomography scanning are equivalent to 1-5 mGy X-rays.

  12. 18FDG PET in a pregnant patient

    International Nuclear Information System (INIS)

    Chatterton, Barry

    2006-01-01

    A 26-year-old pregnant female presented with cervical adenopathy which was shown on biopsy to be Hodgkin's disease. As she had some systemic symptoms, It was decided to further stage her disease, with the options being allowing the pregnancy to continue, or terminating the pregnancy and treating immediately. To keep the radiation dose as low as possible, the administered dose of l8 FDG was reduced giving a total estimated dose to the fetus as 3.2 mGy and l37 Cs used as the source for attenuation correction rather than CT (dose estimated as 0.15mGy instead of 1.5 mGy) Total dose to the fetus was estimated as 3.4mGy. ICRP indicates that termination of pregnancy is not justified for radiation doses less than 100mGy. The findings confirm that an indicated PET scan may be performed in pregnancy at acceptable radiation dose. Relatively straightforward modification of the standard scanning protocol will reduce the estimated fetal dose. Copyright (2006) The Australian and New Zealand Society of Nuclear Medicine

  13. Dose distribution over the radiation field and organs of the body during radiotherapy procedures

    International Nuclear Information System (INIS)

    Roy, S.; Begum, M.; Ambia, A.S.M.; Akhter, S.; Banu, H.

    2001-01-01

    Beam profile of the 60 Co teletherapy unit for 10 cm x 10 cm along central axis was measured to study the symmetry of the gamma beam and found that the average dose was 98.44±1.40 mGy. Output dose versus field size was also measured and values were found reasonable. Dose prescription to delivery was measured by placing TLD onto the treatment field for lung and cervix cancer patient which was found to be 39.16±2.98 Gy and 50.48±3.68 Gy respectively which are within 2 % and 0.17 % of the prescribed dose as 40.00 and 50.40 Gy respectively, reveals good agreement with the treatment planning. Six typical types of patients (both male and female) with cancers in lung, larynx, breast, cervix, oesophagus and brain treated with 60 Co teletherapy were particularly considered for dose assessment at different critical organs of interest. It was observed that the doses to the lens of eye with a maximum value of 460.35+78.87 mGy for a larynx cancer patient to a minimum value of 30.80+4.00 mGy of a cervix cancer patient. Doses to the gonad vary with a maximum value of 3810.80+389.76 mGy for a cervix cancer patient to a minimum value of 8.20+1.00 mGy for a brain cancer patient. (author)

  14. Image quality and dose in mammographic images obtained in Mexico City hospitals

    International Nuclear Information System (INIS)

    Ruiz-Trejo, C.; Brandan, M.-E.; Verdejo, M.; Flores, A.; Guevara, M.; Martin, J.; Madero-Preciado, L.

    2001-01-01

    The performance of three mammographic systems in large Mexican hospitals has been evaluated, as well as the image quality and associated dose. Quality control tests include examination of X-ray equipment, darkroom conditions, film processor, and viewboxes. Systems referred to as '1', '2', and '3' passed 50%, 75% and 75% of these tests, respectively. Quality image is assessed using five images obtained under similar nominal conditions in each X-ray equipment. System 1 generates no image of acceptable quality, while equipment 2 and 3 produce one and two, respectively. The mean glandular dose for the best images obtained in each service with an accreditation phantom has been measured, and the values are 1.4 mGy, 1.6 mGy, and 1.0 mGy, respectively. (author)

  15. Guidelines for the physician's behaviour after exposure of embryos or fetuses to ionizing radiation or after incorporation of radioactive substances for medical purposes

    International Nuclear Information System (INIS)

    Leppin, W.

    1980-01-01

    These guidelines intend to give the physician information on his further actions if radiation has been used in pregnant women for diagnostic purposes, and especially on the medical advice to be given to the woman. The guidelines deal mainly with radiation exposures up to a dose of 20 mGy (2 rd). The guidelines are to show that there is no indication in this dose range for the necessity of an abortion. If doses have been higher than 20 mGy (2 rd), which may be the fact in only a few cases, careful and complex diagnostic efforts are required for the decision on an abortion. The guidelines give some information also on the dose range above 20 mGy (2 rd). (orig.) [de

  16. Radiation risk to the patient: a case study involving multiple diagnostic X ray exposures given over a period of 25 years

    International Nuclear Information System (INIS)

    Rainbow, A.J.; McMaster Univ., Hamilton, ON; Roginski, P.; McGeen, W.

    1992-01-01

    The cumulative somatic dose index (SDI) for a number of diagnostic X ray examinations was made for a 60 year old male. The history of diagnostic X ray exposure for this patient from 1957 to 1983 showed 29 diagnostic X ray examinations including more than 100 films and 15 minutes of fluoroscopy. The total cumulative SDI to this patient was 214 mGy (about 21 rad). More than half this dose, 142 mGy, was contributed from upper GI and barium enema examinations which used fluoroscopy, with 88 mGy from the fluoroscopy alone. Using the recently revised risk coefficient for fatal cancer following whole-body irradiation of adult workers recommended by the International Commission on Radiological Protection in 1990, the authors estimate a 0.9% cancer morality risk to this patient resulting from the 29 diagnostic X ray examinations. (author)

  17. Reference dose levels for dental periapical radiography in Chonnam Province

    International Nuclear Information System (INIS)

    Han, Mi Ra; Kang, Byung Cheol; Yoon, Suk Ja; Lee, Jae Seo; Kim, Young Hee

    2009-01-01

    To establish reference doses of periapical radiography in Chonnam Province, Korea. The target-skin distances were measured for dental patient's 1235 exposures including 345 mandibular molar areas. Each periapical radiation exposure was simulated with exactly the same patients exposure parameters and the simulated radiation doses were measured utilizing Mult-O-Meter (Unfors Instruments, Billadal, Sweden). The measurements were done in 44 dental clinics with 49 dental x-ray sets in Chonnam Province for one or two weeks at each dental clinic during year 2006. The third quartile patient surface doses were 2.8 mGy for overall periapical exposures and 3.2 mGy for periapical mandibular molar exposures. The third quartile patient surface doses in Chonnam Province can be used as a guide to accepted clinical practice to reduce patient radiation exposure for the surveyed reference doses were below the recommended dental periapical radiography dose of 7 mGy by IAEA.

  18. Organ or tissue doses, effective dose and collective effective dose from X-ray diagnosis, in Japan

    International Nuclear Information System (INIS)

    Murayama, Takashi; Nishizawa, Kanae; Noda, Yutaka; Kumamoto, Yoshikazu; Iwai, Kazuo.

    1996-01-01

    Effective doses and collective effective doses from X-ray diagnostic examinations were calculated on the basis of the frequency of examinations estimated by a nationwide survey and the organ or tissue doses experimentally determined. The average organ or tissue doses were determined with thermoluminescence dosimeters put at various sites of organs or tissues in an adult and a child phantom. Effective doses (effective dose equivalents) were calculated as the sum of the weighted equivalent doses in all the organs or tissues of the body. As the examples of results, the effective doses per radiographic examination were approximately 7 mGy for male, and 9 mGy for female angiocardiography, and about 3 mGy for barium meal. Annual collective effective dose from X-ray diagnostic examinations in 1986 were about 104 x 10 3 person Sv from radiography and 118 x 10 3 person Sv from fluoroscopy, with the total of 222 x 10 3 person Sv. (author)

  19. Study of the radiated energy loss during massive gas injection mitigated disruptions on EAST

    Science.gov (United States)

    Duan, Y. M.; Hao, Z. K.; Hu, L. Q.; Wang, L.; Xu, P.; Xu, L. Q.; Zhuang, H. D.; EAST Team

    2015-08-01

    The MGI mitigated disruption experiments were carried out on EAST with a new fast gas controlling valve in 2012. Different amounts of noble gas He or mixed gas of 99% He + 1% Ar are injected into plasma in current flat-top phase and current ramp-down phase separately. The initial results of MGI experiments are described. The MGI system and the radiation measurement system are briefly introduced. The characteristics of radiation distribution and radiation energy loss are analyzed. About 50% of the stored thermal energy Wdia is dissipated by radiation during the entire disruption process and the impurities of C and Li from the PFC play important roles to radiative energy loss. The amount of the gas can affect the pre-TQ phase. Strong poloidal asymmetry of radiation begins to appear in the CQ phase, which is possibly caused by the plasma configuration changes as a result of VDE. No toroidal radiation asymmetry is observed presently.

  20. Reference dose levels for dental periapical radiography in Chonnam Province

    Energy Technology Data Exchange (ETDEWEB)

    Han, Mi Ra; Kang, Byung Cheol; Yoon, Suk Ja [Department of Oral and Maxillofacial Radiology, College of Dentistry, Dental Science Research Institute, Chonnam National University, Gwangju (Korea, Republic of); Lee, Jae Seo [Department of Oral and Maxillofacial Radiology, Chonnan National University Hospital, Gwangju (Korea, Republic of); Kim, Young Hee [Department of Oral and Maxillofacial Radiology, Hallym University Sacred Heart Hospital, Chuncheon (Korea, Republic of)

    2009-12-15

    To establish reference doses of periapical radiography in Chonnam Province, Korea. The target-skin distances were measured for dental patient's 1235 exposures including 345 mandibular molar areas. Each periapical radiation exposure was simulated with exactly the same patients exposure parameters and the simulated radiation doses were measured utilizing Mult-O-Meter (Unfors Instruments, Billadal, Sweden). The measurements were done in 44 dental clinics with 49 dental x-ray sets in Chonnam Province for one or two weeks at each dental clinic during year 2006. The third quartile patient surface doses were 2.8 mGy for overall periapical exposures and 3.2 mGy for periapical mandibular molar exposures. The third quartile patient surface doses in Chonnam Province can be used as a guide to accepted clinical practice to reduce patient radiation exposure for the surveyed reference doses were below the recommended dental periapical radiography dose of 7 mGy by IAEA.

  1. Dosimetry of beta particles using Li:Mg, Cu, P + Ptfe

    International Nuclear Information System (INIS)

    Olvera, L.; Azorin, J.; Rivera, T.

    2003-01-01

    This paper presents the experimental results of determining the thermoluminescence (Tl) response of LiF: Mg, Cu, P + Ptfe pellets excited with 90 Sr/ 90 Y beta radiation. The glow curve exhibited three peaks which appear at 121 C, 178 C and 217 C . Its relative sensitivity is 49 with respect to that of the TLD-100 dosemeter taken as a reference. The minimal dose that could be measured was 750 mGy. The Tl response as a function of dose was linear in the range of 0.7 mGy to 22.5 mGy. The study of the repeatability of the information contained in the pellets showed a standard deviation of 2 %. (Author)

  2. Materials Genome Initiative

    Science.gov (United States)

    Vickers, John

    2015-01-01

    The Materials Genome Initiative (MGI) project element is a cross-Center effort that is focused on the integration of computational tools to simulate manufacturing processes and materials behavior. These computational simulations will be utilized to gain understanding of processes and materials behavior to accelerate process development and certification to more efficiently integrate new materials in existing NASA projects and to lead to the design of new materials for improved performance. This NASA effort looks to collaborate with efforts at other government agencies and universities working under the national MGI. MGI plans to develop integrated computational/experimental/ processing methodologies for accelerating discovery and insertion of materials to satisfy NASA's unique mission demands. The challenges include validated design tools that incorporate materials properties, processes, and design requirements; and materials process control to rapidly mature emerging manufacturing methods and develop certified manufacturing processes

  3. Neuroimmune response and sleep studies after whole body irradiation with high-LET particles

    Science.gov (United States)

    Marquette, C.; Mathieu, J.; Bertho, J.-M.; Galonnier, M.; Wysoki, J.; Maubert, C.; Balanzat, E.; Gerbin, R.; Aigueperse, J.; Clarençon, D.

    2009-10-01

    In order to investigate the biological effects of galactic rays on astronaut cerebral functions after space flight, mice were exposed to different heavy ions (HZE) in whole-body conditions at doses comparable to the galactic flux: 12C, 16O and 20Ne (95 MeV/u, at 42-76 mGy). Animals were also exposed to 42 mGy of 60Co radiation for comparison with HZE. The neuroimmune response, evaluated by interleukin-1 (IL-1) measurement, showed that this cytokine was produced 3 h after irradiation by 16O or 60Co. In contrast, neither 12C (56.7 mGy) nor 20Ne (76 mGy) induced IL-1 production. However, immunohistochemical staining of 12C-irradiated mouse brain tissue showed 2 months later a marked inflammatory reaction in the hippocampus and a diffuse response in parenchyma. Sleep studies were realized before and after exposure to 42 mGy of 16O and 76 mGy of 20Ne: only the 20Ne radiation displayed a small effect. A slight decrease in paradoxical sleep, corresponding to a reduction in the number of episodes of paradoxical sleep, was manifested between 8 and 22 days after exposure. Exposure to 12C and 16O induced no changes either in cellularity of spleen or thymus, or in caspase 3 activity (as much as four months after irradiation). Taken together, these data indicate that the CNS could be sensitive to heavy ions and that responses to HZE impact depend on the nature of the particle, the dose threshold and the time delay to develop biological processes. Differences in responses to different HZE highlight the complex biological phenomena to which astronauts are submitted during space flight.

  4. Neuro-immune response and sleep studies after whole body irradiation with high-LET particles

    International Nuclear Information System (INIS)

    Marquette, C.; Bertho, J.M.; Wysoki, J.; Maubert, C.; Gerbin, R.; Aigueperse, J.; Mathieu, J.; Galonnier, M.; Clarencon, D.; Balanzat, E.

    2009-01-01

    In order to investigate the biological effects of galactic rays on astronaut cerebral functions after space flight, mice were exposed to different heavy ions (HZE) in whole-body conditions at doses comparable to the galactic flux: 12 C, 16 O and 20 Ne (95 MeV/u, at 42-76 mGy). Animals were also exposed to 42 mGy of 60 Co radiation for comparison with HZE. The neuro-immune response, evaluated by interleukin-I (IL-1) measurement, showed that this cytokine was produced 3 h after irradiation by 16 O or 60 Co. In contrast, neither 12 C (56.7 mGy) nor 20 Ne (76 mGy) induced IL-1 production. However, immunohistochemical staining of 12 C-irradiated mouse brain tissue showed 2 months later a marked inflammatory reaction in the hippocampus and a diffuse response in parenchyma. Sleep studies were realized before and after exposure to 42 mGy of 16 O and 76 mGy of 20 Ne: only the 20 Ne radiation displayed a small effect. A slight decrease in paradoxical sleep, corresponding to a reduction in the number of episodes of paradoxical sleep, was manifested between 8 and 22 days after exposure. Exposure to 12 C and 16 O induced no changes either in cellularity of spleen or thymus, or in caspase 3 activity (as much as four months after irradiation). Taken together, these data indicate that the CNS could be sensitive to heavy ions and that responses to HZE impact depend on the nature of the particle, the dose threshold and the time delay to develop biological processes. Differences in responses to different HZE highlight the complex biological phenomena to which astronauts are submitted during space flight. (authors)

  5. Use of the EC quality criteria as a common method of inspecting CT laboratories - A pilot project by the Nordic radiation protection authorities

    International Nuclear Information System (INIS)

    Torp, C.G.; Olerud, H.M.; Einarsson, G.; Groen, P.; Leitz, W.; Servomaa, A.

    2001-01-01

    In the frame of Nordic radiation protection co-operation, quality criteria for computed tomography (CT) as published by the European Commission were used for the evaluation of selected CT laboratories in each of the Nordic countries. The mean values for all five countries of the weighted CT dose index (CTDI w ) and dose length product (DLP) were 60 mGy and 740 mGy · cm for CT of the brain, 11 mGy and 420 mGy · cm for CT of the chest, and 40 mGy and 420 mGy · cm for CT of the lumbar spine, respectively. A comparison with the reference levels set in the above mentioned publication gives a diversified result: compliance for the DLP-values is generally achieved with good margins whereas the CTDI w -values were frequently larger for brain and lumbar spine examinations. The radiographic technique was generally also within the recommendations from the EC. Generally most of the image quality criteria were fulfilled, but it must be borne in mind that the study was biased in the way that two local radiologists in consensus evaluated their own images. Image material from only three patients was selected for each of the clinical indications, that means the project was not designed for ranking laboratories, but it is a way of making the departments aware of the need for optimisation regarding image quality and patient dose, and also of the problems associated with this task. During the study suggestions were brought forward concerning amendments of the quality criteria: some need a better definition, some are not relevant for the diagnostic task in question, some could be added. Instead of 'yes' and 'no', a range of maybe 5 levels of visualisation should be introduced in order to better characterize the level of diagnostic performance. (author)

  6. Pediatric CT dose reduction for suspected appendicitis: a practice quality improvement project using artificial Gaussian noise--part 1, computer simulations.

    Science.gov (United States)

    Callahan, Michael J; Kleinman, Patricia L; Strauss, Keith J; Bandos, Andriy; Taylor, George A; Tsai, Andy; Kleinman, Paul K

    2015-01-01

    The purpose of this study was to develop a departmental practice quality improvement project to systematically reduce CT doses for the evaluation of suspected pediatric appendicitis by introducing computer-generated gaussian noise. Two hundred MDCT abdominopelvic examinations of patients younger than 20 years performed with girth-based scanning parameters for suspected appendicitis were reviewed. Two judges selected 45 examinations in which the diagnosis of appendicitis was excluded (14, appendix not visualized; 31, normal appendix visualized). Gaussian noise was introduced into axial image series, creating five additional series acquired at 25-76% of the original dose. Two readers reviewed 270 image series for appendix visualization (4-point Likert scale and arrow localization). Volume CT dose index (CTDIvol) and size-specific dose estimate (SSDE) were calculated by use of patient girth. Confidence ratings and localization accuracy were analyzed with mixed models and nonparametric bootstrap analysis at a 0.05 significance level. The mean baseline SSDE for the 45 patients was 16 mGy (95% CI, 12-20 mGy), and the corresponding CTDIvol was 10 mGy (95% CI, 4-16 mGy). Changes in correct appendix localization frequencies were minor. There was no substantial trend with decreasing simulated dose level (p = 0.46). Confidence ratings decreased with increasing dose reduction (p = 0.007). The average decreases were -0.27 for the 25% simulated dose (p = 0.01), -0.17 for 33% (p = 0.03), and -0.03 for 43% (p = 0.65). Pediatric abdominal MDCT can be performed with 43% of the original dose (SSDE, 7 mGy; CTDIvol, 4.3 mGy) without substantially affecting visualization of a normal appendix.

  7. Assessment of mean glandular dose to patients from digital mammography systems

    International Nuclear Information System (INIS)

    Pwamang, Caroline K.

    2016-07-01

    Mean glandular dose assessment of patients undergoing digital mammography examination has been done. A total of 297 patient data was used for the study. Basic Quality Control tests were done to ascertain the performance of the equipment used. The results of Quality Control tests indicated that the three Mammography units used for this study were functioning within the internationally acceptable performance criteria. Patients with a breast thickness of 30 mm within the two age groups of 40-49 yrs and 50-64 yrs received doses slightly higher than the acceptable dose levels. A patient in the category 40-49 yrs with breast thickness of 30 mm received 1.83 mGy as calculated Mean Glandular Dose, 2.10 mGy was the recorded dose and 1.58 mGy was recorded under the age group 50-64 yrs. These values have deviated by -22%, -40%, and -5.33% respectively from 1.5 mGy which is the recommended dose for a breast thickness of 30 mm. Also patients with breast thickness of 70 mm under the age group 40–49 yrs had a recorded dose of 6.58 mGy, which deviated by -1.21% from the recommended value of 6.5 mGy for that breast thickness. Aside these values, all the other values were within the recommended dose values. The percentage deviation between the recommended values and the calculated values was within ±25% which was a working limit that was set for this work. Doses delivered by the Full-field Digital mammography equipment were higher than doses delivered by the Computered Radiography equipment. The calculated Mean Glandular Doses for the three facilities were within recommended dose values. (author)

  8. Investigation of the Entrance Surface Dose and Dose to Different Organs in Lumbar Spine Imaging

    Directory of Open Access Journals (Sweden)

    Sina S

    2014-12-01

    Full Text Available Background: Dose assessment using proper dosimeters is especially important in radiation protection optimization and imaging justification in diagnostic radiology. Objective: The aim of this study is to obtain the Entrance Skin Dose (ESD of patients undergoing lumbar spine imaging using two thermoluminescence dosimeters TLD-100 (LiF: Mg, Ti and GR-200 (LiF: Mg, Cu, P and also to obtain the absorbed dose to different organs in lumbar spine imaging with several views. Methods: To measure the ESD values of the patients undergoing lumbar spine imaging, the two TLD types were put on their skin surface. The ESD values for different views of lumbar spine imaging were also measured by putting the TLDs at the surface of the Rando phantom. Several TLD chips were inserted inside different organs of Rando phantom to measure the absorbed dose to different organs in lumbar spine imaging. Results: The results indicate that there is a close agreement between the results of the two dosimeters. Based on the results of this experiment, the ESD dose of the 16 patients included in this study varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for GR-200 measurements. The ESDs obtained by putting the two types of TLDs at the surface of Rando phantom are in close agreement. Conclusion: According to the results, the GR200 has greater sensitivity than the TLD-100.

  9. SU-E-I-09: Application of LiF:Mg,Cu (TLD-100H) Dosimeters for in Diagnostic Radiology

    International Nuclear Information System (INIS)

    Sina, S; Zeinali, B; Karimipourfard, M; Lotfalizadeh, F; Sadeghi, M; Faghihi, R

    2014-01-01

    Purpose: Accurate dosimetery is very essential in diagnostic radiology. The goal of this study is to verify the application of LiF:Mg,Cu,P (TLD100H) in obtaining the Entrance skin dose (ESD) of patients undergoing diagnostic radiology. The results of dosimetry performed by TLD-100H, were compared with those obtained by TLD100, which is a common dosimeter in diagnostic radiology. Methods: In this study the ESD values were measured using two types of Thermoluminescence dosimeters (TLD-100, and TLD-100H) for 16 patients undergoing diagnostic radiology (lumbar spine imaging). The ESD values were also obtained by putting the two types of TLDs at the surface of Rando phantom for different imaging techniques and different views (AP, and lateral). The TLD chips were annealed with a standard procedure, and the ECC values for each TLD was obtained by exposing the chips to equal amount of radiation. Each time three TLD chips were covered by thin dark plastic covers, and were put at the surface of the phantom or the patient. The average reading of the three chips was used for obtaining the dose. Results: The results show a close agreement between the dose measuered by the two dosimeters.According to the results of this study, the TLD-100H dosimeters have higher sensitivities (i.e.signal(nc)/dose) than TLD-100.The ESD values varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for measurements. Conclusion: The TLD-100H dosimeters are suggested as effective dosimeters for dosimetry in low dose fields because of their higher sensitivities

  10. SU-E-I-09: Application of LiF:Mg,Cu (TLD-100H) Dosimeters for in Diagnostic Radiology

    Energy Technology Data Exchange (ETDEWEB)

    Sina, S [Radiation Research Center, Shiraz University, Shiraz (Iran, Islamic Republic of); Zeinali, B; Karimipourfard, M; Lotfalizadeh, F; Sadeghi, M [Nuclear Engineering Department, Shiraz University, Shiraz (Iran, Islamic Republic of); Faghihi, R [Radiation Research Center, Shiraz University, Shiraz (Iran, Islamic Republic of); Nuclear Engineering Department, Shiraz University, Shiraz (Iran, Islamic Republic of)

    2014-06-01

    Purpose: Accurate dosimetery is very essential in diagnostic radiology. The goal of this study is to verify the application of LiF:Mg,Cu,P (TLD100H) in obtaining the Entrance skin dose (ESD) of patients undergoing diagnostic radiology. The results of dosimetry performed by TLD-100H, were compared with those obtained by TLD100, which is a common dosimeter in diagnostic radiology. Methods: In this study the ESD values were measured using two types of Thermoluminescence dosimeters (TLD-100, and TLD-100H) for 16 patients undergoing diagnostic radiology (lumbar spine imaging). The ESD values were also obtained by putting the two types of TLDs at the surface of Rando phantom for different imaging techniques and different views (AP, and lateral). The TLD chips were annealed with a standard procedure, and the ECC values for each TLD was obtained by exposing the chips to equal amount of radiation. Each time three TLD chips were covered by thin dark plastic covers, and were put at the surface of the phantom or the patient. The average reading of the three chips was used for obtaining the dose. Results: The results show a close agreement between the dose measuered by the two dosimeters.According to the results of this study, the TLD-100H dosimeters have higher sensitivities (i.e.signal(nc)/dose) than TLD-100.The ESD values varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for measurements. Conclusion: The TLD-100H dosimeters are suggested as effective dosimeters for dosimetry in low dose fields because of their higher sensitivities.

  11. Investigation of the Entrance Surface Dose and Dose to Different Organs in Lumbar Spine Imaging

    Science.gov (United States)

    Sina, S; Zeinali, B; Karimipoorfard, M; Lotfalizadeh, F; Sadeghi, M; Zamani, E; Faghihi, R

    2014-01-01

    Background: Dose assessment using proper dosimeters is especially important in radiation protection optimization and imaging justification in diagnostic radiology. Objective: The aim of this study is to obtain the Entrance Skin Dose (ESD) of patients undergoing lumbar spine imaging using two thermoluminescence dosimeters TLD-100 (LiF: Mg, Ti) and GR-200 (LiF: Mg, Cu, P) and also to obtain the absorbed dose to different organs in lumbar spine imaging with several views. Methods: To measure the ESD values of the patients undergoing lumbar spine imaging, the two TLD types were put on their skin surface. The ESD values for different views of lumbar spine imaging were also measured by putting the TLDs at the surface of the Rando phantom. Several TLD chips were inserted inside different organs of Rando phantom to measure the absorbed dose to different organs in lumbar spine imaging. Results: The results indicate that there is a close agreement between the results of the two dosimeters. Based on the results of this experiment, the ESD dose of the 16 patients included in this study varied between 2.71 mGy and 26.29 mGy with the average of 11.89 mGy for TLD-100, and between 2.55 mGy and 27.41 mGy with the average of 12.32 mGy for GR-200 measurements. The ESDs obtained by putting the two types of TLDs at the surface of Rando phantom are in close agreement. Conclusion: According to the results, the GR200 has greater sensitivity than the TLD-100. PMID:25599058

  12. SU-F-I-36: In-Utero Dose Measurements Within Postmortem Subjects for Estimating Fetal Doses in Pregnant Patients Examined with Pulmonary Embolism, Trauma, and Appendicitis CT

    Energy Technology Data Exchange (ETDEWEB)

    Lipnharski, I; Quails, N; Carranza, C; Correa, N; Bidari, S; Bickelhaup, M; Rill, L; Arreola, M [University of Florida, Gainesville, FL (United States)

    2016-06-15

    Purpose: The imaging of pregnant patients is medically necessary in certain clinical situations. The purpose of this work was to directly measure uterine doses in a cadaver scanned with CT protocols commonly performed on pregnant patients in order to estimate fetal dose and assess potential risk. Method: One postmortem subject was scanned on a 320-slice CT scanner with standard pulmonary embolism, trauma, and appendicitis protocols. All protocols were performed with the scan parameters and ranges currently used in clinical practice. Exams were performed both with and without iterative reconstruction to highlight the dose savings potential. Optically stimulated luminescent dosimeters (OSLDs) were inserted into the uterus in order to approximate fetal doses. Results: In the pulmonary embolism CT protocol, the uterus is outside of the primary beam, and the dose to the uterus was under 1 mGy. In the trauma and appendicitis protocols, the uterus is in the primary beam, the fetal dose estimates were 30.5 mGy for the trauma protocol, and 20.6 mGy for the appendicitis protocol. Iterative reconstruction reduced fetal doses by 30%, with uterine doses at 21.3 for the trauma and 14.3 mGy for the appendicitis protocol. Conclusion: Fetal doses were under 1 mGy when exposed to scatter radiation, and under 50 mGy when exposed to primary radiation with the trauma and appendicitis protocols. Consistent with the National Council on Radiation Protection & Measurements (NCRP) and the International Commission on Radiological Protection (ICRP), these doses exhibit a negligible risk to the fetus, with only a small increased risk of cancer. Still, CT scans are not recommended during pregnancy unless the benefits of the exam clearly outweigh the potential risk. Furthermore, when possible, pregnant patients should be examined on CT scanners equipped with iterative reconstruction in order to keep patient doses as low as reasonable achievable.

  13. Assessment of Regional Pediatric Computed Tomography Dose Indices in Tamil Nadu.

    Science.gov (United States)

    Saravanakumar, A; Vaideki, K; Govindarajan, K N; Jayakumar, S; Devanand, B

    2017-01-01

    The aim of this article is to assess Tamil Nadu pediatric computed tomography (CT) diagnostic reference levels (DRLs) by collecting radiation dose data for the most commonly performed CT examinations. This work was performed for thirty CT scanners installed in various parts of the Tamil Nadu region. The patient cohort was divided into two age groups: <1 year, and 1-5 years. CT dose indices were measured using a 10 cm 3 pencil ion chamber with pediatric head and body polymethyl methacrylate phantoms. Dose data such as volumetric CT dose index (CTDI v ) and dose length product (DLP) on a minimum of twenty average-sized pediatric patients in each category were recorded to calculate a mean site CTDI v and DLP value. The rounded 75 th percentile was used to calculate a pediatric DRL for each hospital, and then region by compiling all results. Data were collected for 3600 pediatric patients. Pediatric CT DRL for two age groups: <1 year (CTDI v and DLP of head [20 mGy, 352 mGy.cm], chest [7 mGy, 120 mGy.cm] and abdomen [12 mGy, 252 mGy.cm]), and 1-5 years (CTDI v and DLP of head [38 mGy, 505 mGy.cm], chest [8 mGy, 132 mGy.cm] and abdomen [14 mGy, 270 mGy.cm]) for select procedures have been calculated. Proposed pediatric DRLs of CTDI v and DLP for head procedure were lower, and for chest and abdomen procedures were higher than European pediatric DRLs for both age groups.

  14. Assessment of DNA double-strand breaks induced by intravascular iodinated contrast media following in vitro irradiation and in vivo, during paediatric cardiac catheterization.

    Science.gov (United States)

    Gould, Richard; McFadden, Sonyia L; Horn, Simon; Prise, Kevin M; Doyle, Philip; Hughes, Ciara M

    2016-01-01

    Paediatric cardiac catheterizations may result in the administration of substantial amounts of iodinated contrast media and ionizing radiation. The aim of this work was to investigate the effect of iodinated contrast media in combination with in vitro and in vivo X-ray radiation on lymphocyte DNA. Six concentrations of iodine (15, 17.5, 30, 35, 45, and 52.5 mg of iodine per mL blood) represented volumes of iodinated contrast media used in the clinical setting. Blood obtained from healthy volunteers was mixed with iodinated contrast media and exposed to radiation doses commonly used in paediatric cardiac catheterizations (0 mGy, 70 mGy, 140 mGy, 250 mGy and 450 mGy). Control samples contained no iodine. For in vivo experimentation, pre and post blood samples were collected from children undergoing cardiac catheterization, receiving iodine concentrations of up to 51 mg of iodine per mL blood and radiation doses of up to 400 mGy. Fluorescence microscopy was performed to assess γH2AX-foci induction, which corresponded to the number of DNA double-strand breaks. The presence of iodine in vitro resulted in significant increases of DNA double-strand breaks beyond that induced by radiation for ≥ 17.5 mg/mL iodine to blood. The in vivo effects of contrast media on children undergoing cardiac catheterization resulted in a 19% increase in DNA double-strand breaks in children receiving an average concentration of 19 mg/mL iodine to blood. A larger investigation is required to provide further information of the potential benefit of lowering the amount of iodinated contrast media received during X-ray radiation investigations. Copyright © 2015 John Wiley & Sons, Ltd.

  15. The effects of γ-ray on charging behaviour using polyimide

    Science.gov (United States)

    Qin, Sichen; Tu, Youping; Tan, Tian; Wang, Shaohe; Yuan, Zhikang; Wang, Cong; Li, Laifeng; Wu, Zhixiong

    2018-06-01

    Insulation material is a key component of electrical equipment in satellites; its electrical properties determine the reliability and lifetime of the whole satellite. High-energy radioactive rays in space affect the molecular structure of the polymeric insulating materials. Under the action of plasma, high energy particles, along with the magnetic fields experienced in orbits, electric charges get injected into and trapped by the insulating material creating distortions in the electric field and even electrostatic discharges. Polyimides have been widely used for insulation in spacecraft. Choosing Co-60 gamma ray with irradiation doses of 1 MGy and 5 MGy to simulate the radiation environment of space, we investigated the effect of radiation on charging behaviour. The thermal stimulated current (TSC) from a high electric field over a wide range of temperatures was measured from which the activation energy was calculated. These results for the two sources show that the percentage increase in total charge was 133.3% and 119.4%. The γ, β 3, and α charge peaks of specimens after an irradiation dose of 1 MGy rose. In comparison, the β 2 peak of the 5 MGy-dosed specimens was enhanced. Also, there is almost no change in the γ, β 3, and α peaks. To understand the mechanism behind the TSC changes, the resulting physicochemical characteristics of an irradiated specimen were observed employing various analyses of chemical characteristics (x-ray photoelectron spectroscopy, differential scanning calorimetry and x-ray diffraction). Compared with the non-dosed specimen, the relative content of C–N and the glass transition temperature of the 1 MGy sample decreased, and the crystallinity increased, thus increasing the γ and α peak intensities. Compared with the 1 MGy sample, only the glass transition temperature had risen, thereby enhancing the β peak intensity. With the foregoing, a theoretical base for the selection and modification of insulation materials for

  16. Measurement of photo-neutron cross sections and isomeric yield ratios in the {sup 89}Y(γ,xn){sup 89-x}Y reactions at the bremsstrahlung end-point energies of 65, 70 and 75 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Tatari, Mansoureh [Yazd Univ. (Iran, Islamic Republic of). Physics Dept.; Naik, Haladhara [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.; Kim, Guinyun; Kim, Kwangsoo [Kyungpook National Univ., Daegu (Korea, Republic of). Dept. of Physics; Shin, Sung-Gyun; Cho, Moo-Hyun [Pohang Univ. of Science and Technology (Korea, Republic of). Div. of Advanced Nuclear Engineering

    2017-07-01

    The flux-weighted average cross sections of the {sup 89}Y(γ,xn; x=1-4){sup 89-x}Y reactions and the isomeric yield ratios of the {sup 87m,g}Y, {sup 86m,g}Y, and {sup 85m,g}Y radionuclides produced in these reactions with the bremsstrahlung end-point energies of 65, 70 and 75 MeV have been determined by an activation and off-line γ-ray spectrometric technique using the 100 MeV electron linac in Pohang Accelerator Laboratory, Korea. The theoretical {sup 89}Y(γ,xn; x=1-4){sup 89-x}Y reaction cross sections for mono-energetic photons have been calculated using the computer code TALYS 1.6. Then the flux-weighted theoretical values were obtained to compare with the present data. The flux-weighted experimental and theoretical {sup 89}Y(γ,xn; x=1-4){sup 89-x}Y reaction cross sections increase very fast from the threshold values to a certain bremsstrahlung energy, where the other reaction channels open up. Thereafter it remains constant a while and then slowly decreases with the increase of cross sections for other reactions. Similarly, the isomeric yield ratios of {sup 87m,g}Y, {sup 86m,g}Y and {sup 85m,g}Y in the {sup 89}Y(γ,xn; x=2-4){sup 89-x}Y reactions from the present work and literature data show an increasing trend from their respective threshold values to a certain bremsstrahlung energy. After a certain point of energy, the isomeric yield ratios increase slowly with the bremsstrahlung energy. These observations indicate the role of excitation energy and its partitioning in different reaction channels.

  17. The biological effects of exposure to ionising radiation

    International Nuclear Information System (INIS)

    Higson, D.J.

    2016-01-01

    Scenarios for exposure to ionising radiation range from natural background radiation (chronic) to the explosions of atomic bombs (acute), with some medical, industrial and research exposures lying between these extremes. Biological responses to radiation that predominate at high doses incurred at high dose rates are different from those that predominate at low doses and low dose rates. Single doses from bomb explosions ranged up to many thousand mGy. Acute doses greater than about 1000 mGy cause acute radiation syndrome (ARS). Below this threshold, radiation has a variety of potential latent health effects: Change to the incidence of cancer is the most usual subject of attention but change to longevity may be the best overall measure because decreased incidences of non-cancer mortality have been observed to coincide with increased incidence of cancer mortality. Acute doses greater than 500 mGy cause increased risks of cancer and decreased life expectancy. For doses less than 100 mGy, beneficial overall health effects ('radiation hormesis') have been observed. At the other end of the spectrum, chronic exposure to natural radiation has occurred throughout evolution and is necessary for the normal life and health of current species. Dose rates greater than the present global average of about 2 mGy per year have either no discernible health effect or beneficial health effects up to several hundred mGy per year. It is clearly not credible that a single health effects model -- such as the linear no-threshold (LNT) model of risk estimation -- could fit all latent health effects. A more realistic model is suggested.

  18. Performance degradation of ferrofluidic feedthroughs in a mixed irradiation field

    Science.gov (United States)

    Simos, Nikolaos; Fernandes, S.; Mittig, Wolfgang; Pellemoine, Frederique; Avilov, M.; Kostin, M.; Mausner, L.; Ronningen, R.; Schein, M.; Bollen, G.

    2017-01-01

    Ferrofluidic feedthrough (FF) rotary seals containing either NdFeB or SmCo-type permanent magnets have been considered for use in the target and beam dump systems of the Facility for Rare Isotope Beams (FRIB). To evaluate their performance under irradiation three FF seals were irradiated in a mixed field consisting of fast neutrons, protons and γ-rays to an average absorbed dose of 0.2, 2.0, and 20.0 MGy at the Brookhaven Linac Isotope Producer facility (BLIP). The radiation types and energy profiles mimic those expected at the FRIB facility. Degradation of the operational performance of these devices due to irradiation is expected to be the result of the de-magnetization of the permanent magnets contained within the seal and the changes in the ferrofluid properties. Post-irradiation performance was evaluated by determining the ferrofluidic seal vacuum tightness and torque under static and dynamic conditions. The study revealed that the ferrofluidic feedthrough seal irradiated to a dose of 0.2 MGy maintained its vacuum tightness under both static and rotational condition while the one irradiated to a dose of 2.0 MGy exhibited signs of ferrofluid damage but no overall performance loss. At 20 MGy dose the effects of irradiation on the ferrofluid properties (viscosity and particle agglomeration) were shown to be severe. Furthermore, limited de-magnetization of the annular shaped Nd2Fe14B and Sm2Co17 magnets located within the irradiated FFs was observed for doses of 0.2 MGy and 20 MGy respectively.

  19. Effect of low dose radiation on expression of hematopoietic growth factors secreted by human mesenchymal stem cells from bone marrow

    International Nuclear Information System (INIS)

    Yang Yan; Wang Guanjun; Zhu Jingyan; Wang Juan

    2008-01-01

    Objective: To study the changes of hematopoietic growth factors secreted by human mesenchymal stem cells from bone marrow (BM-MSC) pretreated with low dose radiation (LDR). Methods: The cultured P4 and P5 BM-MSCs were exposed to X rays at the doses of 50, 75 and 100 mGy (dose rate 12.5 mGy·min -1 ). The changes of levels of stem cell factor (SCF), IL-6, macrophage colony-stimulating factor (M-CSF) secreted by BM- MSCs pretreated with LDR were determined by ELISA method. Results: As compared with control group at the same time, the levels of SCF in experimental group had a tendency of increasing after 24 h and 48 h radiation, but only in 75 mGy group the SCF level was obviously increased (P<0.05). The levels of IL-6 in 50 and 75 mGy groups at 24 h and 48 h, in 100 mGy group at 24 h were obviously increased compared with control group (P< 0.05). The levels of M-CSF in all the groups at 24 h, 48 h and 72 h except for the 50 mGy dose at 72 h were also increased (P<0.05), it increased markedly in 75 mGy dose group at 72 h. Conclusion: LDR has hormesis effect on BM-MSCs. After LDR, the BM-MSCs grow faster and in a certain phase the expression levels of hematopoietic growth factors are increased. (authors)

  20. Primary beam ionizing radiation for patients during coronary cineangiography

    International Nuclear Information System (INIS)

    Ramirez, Alfredo; Leyton, Fernando; Gamarra, Jorge; Oyarzun C, Carlos; Silva, Ana Maria; Ugalde, Hector; Dussaillant, Gaston

    2001-01-01

    Current cardiology practice incorporates hemodynamic and angiographic studies as normal procedures. Clinical actions have to be taken in interventionist cardiology that demand prolonged exposure times to radiation, which implies submitting patients to quantitatively significant doses. This work is a preliminary phase for clinical studies involving long procedures in hemodynamic and electrophysiological interventionist cardiology to show the magnitude of the radiation doses received by the patients after a proper diagnosis. The aim is to improve the patient's radiological protection as well as that of the staff involved. The study group consisted of 18 patients who underwent coronary angiography procedures with Siemens Angioskop D equipment and a Siemens Polidoros 80 generator. Four TLD Crystal detectors were used for the patient's dosimetry, which were located in the dorsal region along the left para scapular line, on the mid line of the thyroid region and a detector on the mid point between the umbilical zone and the pubis symphysis. For procedure times of 14±4.3 min., with fluoroscope times of 3.6±2.5 min., connection techniques of 87±15 kV. and 126±24 mA, the radiations recorded in the left inter scapular and right inter scapular regions were 215±199 mGy (1-710 mGy range) and 255±212 mGy ( 22 - 791mGy range ). The radiations in the pubic and thyroid regions were 0.23±0.07 mGy and 3.62±2.44 mGy, respectively (CO)

  1. Survey of pediatric MDCT radiation dose from university hospitals in Thailand. A preliminary for national dose survey

    Energy Technology Data Exchange (ETDEWEB)

    Kritsaneepaiboon, Supika [Dept. of Radiology, Faculty of Medicine, Prince of Songkla Univ., Hat Yai (Thailand)], e-mail: supikak@yahoo.com; Trinavarat, Panruethai [Dept. of Radiology, Faculty of Medicine, Chulalongkorn Univ., Bangkok (Thailand); Visrutaratna, Pannee [Dept. of Radiology, Faculty of Medicine, Chiang Mai Univ., Chiang Mai (Thailand)

    2012-09-15

    Background: Increasing pediatric CT usage worldwide needs the optimization of CT protocol examination. Although there are previous published dose reference level (DRL) values, the local DRLs should be established to guide for clinical practice and monitor the CT radiation. Purpose: To determine the multidetector CT (MDCT) radiation dose in children in three university hospitals in Thailand in four age groups using the CT dose index (CTDI) and dose length product (DLP). Material and Methods: A retrospective review of CT dosimetry in pediatric patients (<15 years of age) who had undergone head, chest, and abdominal MDCT in three major university hospitals in Thailand was performed. Volume CTDI (CTDIvol) and DLP were recorded, categorized into four age groups: <1 year, 1- < 5 years, 5- <10 years, and 10- <15 years in each scanner. Range, mean, and third quartile values were compared with the national reference dose levels for CT in pediatric patients from the UK and Switzerland according to International Commission on Radiological Protection (ICRP) recommendation. Results: Per age group, the third quartile values for brain, chest, and abdominal CTs were, respectively, in terms of CTDIvol: 25, 30, 40, and 45 mGy; 4.5, 5.7, 10, and 15.6 mGy; 8.5, 9, 14, and 17 mGy; and in terms of DLP: 400, 570, 610, and 800 mGy cm; 80, 140, 305, and 470 mGy cm; and 190, 275, 560,765 mGy cm. Conclusion: This preliminary national dose survey for pediatric CT in Thailand found that the majority of CTDIvol and DLP values in brain, chest, and abdominal CTs were still below the diagnostic reference levels (DRLs) from the UK and Switzerland regarding to ICRP recommendation.

  2. Evaluation of dose to tooth enamel from medical diagnostic X-ray examinations at Mayak PA

    Energy Technology Data Exchange (ETDEWEB)

    Wieser, A., E-mail: wieser@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany); Vasilenko, E. [Mayak Production Association, 456780 Ozyorsk (Russian Federation); Zankl, M.; Greiter, M.; Ulanovsky, A. [Helmholtz Zentrum Muenchen - German Research Center for Environmental Health, Institute of Radiation Protection, D-85764 Neuherberg (Germany); Sabayev, A.; Knyazev, V.; Zahrov, P. [Mayak Production Association, 456780 Ozyorsk (Russian Federation)

    2011-09-15

    The nuclear workers of the Mayak Production Association had regular check-ups including medical diagnostic X-ray examinations since start of the production lines in 1948. Doses from diagnostic examinations need to be considered in reconstruction of occupational doses of the workers with electron paramagnetic resonance (EPR) of tooth enamel. The numbers and types of examinations of an individual worker can be assessed from the Mayak PA archives but no information was available on doses delivered to teeth by a single specific examination. Of the twenty one applied examination procedures only three affected the teeth, these being X-ray examinations of teeth, skull and cervical spine. For these three kinds of examinations operational procedures and operating modes of X-ray units were compiled from the archive and photon spectra were obtained from a catalog of spectral data for diagnostic X-rays. Entrance doses in air kerma were calculated using the fluence of photon spectra and absorbed dose in tooth enamel for various tooth positions and exposure geometry was then calculated using dose conversion coefficients obtained from Monte Carlo simulations. Doses were calculated for examinations in 1948-2000. Except for examination of the skull, absorbed doses in enamel of incisors were found to be about twice as large as in enamel of molars. In the period before 1970 the largest mean absorbed doses in tooth enamel were due to X-ray examination of teeth, with 64 mGy and 34 mGy calculated for incisors and molars, respectively. In the same period the lowest mean doses were due to X-ray examination of the skull, with 11 mGy and 12 mGy calculated for incisors and molars, respectively. In the period from 1970 to 2000, largest mean doses in enamel were due to X-ray examination of cervical spine, with 23 mGy and 12 mGy calculated for incisors and molars, respectively.

  3. SU-E-J-11: Measurement of Eye Lens Dose for Varian On-Board Imaging with Different CBCT Acquisition Techniques

    International Nuclear Information System (INIS)

    Deshpande, S; Dhote, D; Kumar, R; Thakur, K

    2015-01-01

    Purpose: To measure actual patient eye lens dose for different cone beam computed tomography (CBCT) acquisition protocol of Varian’s On Board Imagining (OBI) system using Optically Stimulated Luminescence (OSL) dosimeter and study the eye lens dose with patient geometry and distance of isocenter to the eye lens Methods: OSL dosimeter was used to measure eye lens dose of patient. OSL dosimeter was placed on patient forehead center during CBCT image acquisition to measure eye lens dose. For three different cone beam acquisition protocol (standard dose head, low dose head and high quality head) of Varian On-Board Imaging, eye lens doses were measured. Measured doses were correlated with patient geometry and distance between isocenter to eye lens. Results: Measured eye lens dose for standard dose head was in the range of 1.8 mGy to 3.2 mGy, for high quality head protocol dose was in range of 4.5mGy to 9.9 mGy whereas for low dose head was in the range of 0.3mGy to 0.7mGy. Dose to eye lens is depends upon position of isocenter. For posterioraly located tumor eye lens dose is less. Conclusion: From measured doses it can be concluded that by proper selection of imagining protocol and frequency of imaging, it is possible to restrict the eye lens dose below the new limit set by ICRP. However, undoubted advantages of imaging system should be counter balanced by careful consideration of imaging protocol especially for very intense imaging sequences for Adoptive Radiotherapy or IMRT

  4. Patient doses in interventional cardiology procedures

    International Nuclear Information System (INIS)

    Domienik, J.; Papierz, S.; Jankowski, J.; Peruga, J.Z.

    2008-01-01

    In most countries of European Union legislation requires the determination of the total skin dose to patient resulting from interventional procedures to assess the risk of deterministic effect. To this end, various dose indicators like dose area product (DAP), cumulative dose (CD) and entrance dose at the patient plane (EFD) are used in clinical practice. The study aims at relating those dose indicators with doses ascribe to the most irradiated areas of the patient skin usually expressed in terms of local maximal skin dose (MSD). For the study the local MSD and related to their areas are investigated and compared for coronary angiography CA and intervention (PCI). Two methods implying radiographic films Kodak EDR2 and matrixes of thermoluminescent dosimeters (TLDs) are applied for direct measurements of dose distribution for selected procedures. Both methods are compared. Additionally, for patient dosimetry the following data: MSD, CD, EFD, fluoroscopy time (FT), number of acquired images, total DAP, fluoro-DAP and record-DAP were collected for randomly selected procedure. The statistical quantities like: median, 3 rd quartile, mean and standard deviation for all dosimetric parameters are determined. Preliminary study showed that the values of data collected for coronary procedures are in the ranges 0,7 - 27,3 min for fluoroscopy time, 50 - 350 Gy cm 2 for total DAP, 300 - 2000 mGy for CD, 140 - 2000 mGy for EFD and 100 - 1500 mGy for local maximal skin dose. For interventions the ranges are, accordingly 3,0 - 43,6 min , 25 - 450 Gy cm 2 , 270 - 6600 mGy, 80 - 2600 mGy and 80 - 1500 mGy. As a result of the study the correlations between dose indicators and local MSD are analyzed. The concentration of dose on irradiated films are going to be investigated in some detail as well. (author)

  5. Intracellular magnesium concentrations in dogs with gastric dilatation-volvulus.

    Science.gov (United States)

    Bebchuk, T N; Hauptman, J G; Braselton, W E; Walshaw, R

    2000-11-01

    To quantify and compare intracellular magnesium concentrations (Mgi) in clinically normal dogs (control dogs) and dogs that have gastric dilatation-volvulus (GDV dogs) and to determine whether there is a difference in Mgi and serum magnesium concentrations (Mgs) between GDV dogs with and without cardiac arrhythmias. 41 control dogs and 21 GDV dogs. Rectus abdominis muscle specimens were obtained from control and GDV dogs for determination of Mgi. Blood samples were obtained from GDV dogs for determination of Mgs, and dogs were monitored for 48 hours for cardiac arrhythmias. Muscle specimens were frozen at -40 C, oven dried at 95 C, and digested with concentrated nitric acid. Multielemental analyses were performed by simultaneous/sequential inductively coupled plasma-atomic emission spectroscopy with fixed-cross flow nebulization. The Mg, was standardized to sulfur content to correct for the amount of fat and fascia in the muscle specimen. Mean (+/- SEM) values were recorded in parts per million (ppm). Results-There were no significant differences in Mgi between control (627 +/- 11.1 ppm) and GDV (597 +/- 20.5 ppm) dogs, in Mgi between GDV dogs with (590 +/- 34 ppm) and without (584 +/- 29 ppm) cardiac arrhythmias, and in Mgs between GDV dogs with (1.77 +/- 0.26 ppm) and without (1.51 +/- 0.09 ppm) cardiac arrhythmias. There was no correlation between Mgs and Mgi (R2 = 0.0001). Results indicate that Mg depletion is not pathophysiologically important in dogs with GDV and does not play a role in the cardiac arrhythmias detected in these patients.

  6. Survey of image quality and patient dose for computed tomography

    International Nuclear Information System (INIS)

    Augusto, Fernando Mecca

    2009-01-01

    The aim of this work is to evaluate the dose index and the image quality in seventeen computed tomography scanners installed in radiology departments at the city of Rio de Janeiro. The American College of Radiology (ACR) accreditation phantom (Gammex, 464) was used for the image quality evaluation. The following parameters were investigated according to the procedure manual of the ACR phantom: CT number calibration, exactitude of the slice thickness, low and high contrast resolution, uniformity, noise and artifacts. Despite of the CT number accuracy, only one scanner passed in the test. The low contrast resolution and the uniformity criteria were not accomplished in two different scanners. The conformity for the criteria established for slice width and high contrast was not verified in 16% and 11 % of the equipment respectively. The noise, expressed as a standard deviation measured in the center of the image in an adult abdomen protocol, ranged from 2.8 to 9.5. The ACR criteria of the accreditation program were not accomplished in the sample evaluated. Some parameters failed are essential to assure the diagnostic accuracy. For the head scans CTDI 100,VOL values varied between 9 and 109 mGy and the DLP from 160 to 2000 mGy cm for adults. Values for abdomen scans varied between 8 and 94 mGy and the DLP from 180 to 3700 mGy cm for adults, and CTDI 100,VOL from 3 to 54 mGy and DLP from 46 to 1300 mGy cm for children. Similar ranges were found for hi-resolution chest scans. These results are compatibles with those from reported literature and indicate a large potential for optimization and dose reduction, specially in pediatric patients. (author)

  7. Clinical application of low-dose spiral CT for orthodontics

    International Nuclear Information System (INIS)

    Xie Na; Gan Yungen; Shu Huang; Lin FeiFei; Li Zhiyong; Sun Jie

    2009-01-01

    Objective: To determine the effect of reducing the value of mA or kV on the image quality and the radiation dose of the patients undergoing low-dose spiral CT for orthodontics. Methods: Thirty patients were divided into three groups, each group has 10 patients. They were group 1 (80 kV and 200 mA), group 2 (120 kV and 80 mA), group 3 (120 kV and 200 mA) The volume CT dose index (CTDI) was recorded and the average dose-length produce (DLP) was calculated in three groups,respectively. Image quality of three groups were compared and scored by two radiologists, and the results were statistically analysed. Results: The CTDI and DLP of 80 kV group (group 2) were 8.7 mGy and (36.80 ± 3.60) mGy · cm, respectively, those of 80 mA group (group 3) were 19.6 mGy and (82.14 ± 7.18) mGy · cm, respectively, and those of conventional-dose group (group 1) were 19.6 mGy and (82.14 ± 7.18) mGy · cm, respectively. There was no significant difference among three groups in diagnostic image quality. Conclusions: Low-dose spiral CT for orthodontics, especially the low-kV scan, may decrease the radiation exposure and guarantee the image quality. (authors)

  8. SU-F-I-36: In-Utero Dose Measurements Within Postmortem Subjects for Estimating Fetal Doses in Pregnant Patients Examined with Pulmonary Embolism, Trauma, and Appendicitis CT

    International Nuclear Information System (INIS)

    Lipnharski, I; Quails, N; Carranza, C; Correa, N; Bidari, S; Bickelhaup, M; Rill, L; Arreola, M

    2016-01-01

    Purpose: The imaging of pregnant patients is medically necessary in certain clinical situations. The purpose of this work was to directly measure uterine doses in a cadaver scanned with CT protocols commonly performed on pregnant patients in order to estimate fetal dose and assess potential risk. Method: One postmortem subject was scanned on a 320-slice CT scanner with standard pulmonary embolism, trauma, and appendicitis protocols. All protocols were performed with the scan parameters and ranges currently used in clinical practice. Exams were performed both with and without iterative reconstruction to highlight the dose savings potential. Optically stimulated luminescent dosimeters (OSLDs) were inserted into the uterus in order to approximate fetal doses. Results: In the pulmonary embolism CT protocol, the uterus is outside of the primary beam, and the dose to the uterus was under 1 mGy. In the trauma and appendicitis protocols, the uterus is in the primary beam, the fetal dose estimates were 30.5 mGy for the trauma protocol, and 20.6 mGy for the appendicitis protocol. Iterative reconstruction reduced fetal doses by 30%, with uterine doses at 21.3 for the trauma and 14.3 mGy for the appendicitis protocol. Conclusion: Fetal doses were under 1 mGy when exposed to scatter radiation, and under 50 mGy when exposed to primary radiation with the trauma and appendicitis protocols. Consistent with the National Council on Radiation Protection & Measurements (NCRP) and the International Commission on Radiological Protection (ICRP), these doses exhibit a negligible risk to the fetus, with only a small increased risk of cancer. Still, CT scans are not recommended during pregnancy unless the benefits of the exam clearly outweigh the potential risk. Furthermore, when possible, pregnant patients should be examined on CT scanners equipped with iterative reconstruction in order to keep patient doses as low as reasonable achievable.

  9. Evaluation of glandular dose in conventional and digital mammography systems

    International Nuclear Information System (INIS)

    Coutinho, Celia Maria Campos

    2009-01-01

    A survey was conducted to estimate the average glandular dose (D g ) for patients undergoing mammography and to report the distribution of incident air kerma (K i ), patient age, compressed breast thickness and glandular tissue content. From 1183 cranio caudal mammograms clinical data were collected and doses were measured. The survey data included mammograms from six mammography equipment: two screen/film units (SFM), two computed radiography units (CR) and two full-field digital (DR). Mean value for patient age and compressed breast thickness were 57 +-12 y and 5.4 +-1.4 cm, respectively. To investigate the importance of technical characteristics of three different mammography systems and breast glandularity, K i and D g were measured for individual breast of 392 patients from the original sample with compressed breast thickness in the range of 5.5 cm to 6.5 cm using tissue-equivalent phantoms of different glandularities manufactured in this study to mimic both the attenuation and the density of breast tissues. Mean K i value was 10.0 +-3.6 mGy for SFM systems, 12.0 +-3.6 mGy for CR systems and 4.9 +-1.3 mGy for DR systems. Mean D g value was 1.4 +-0.5 mGy for S/F systems, 1.7 +-0.5 mGy for CR systems and 0.9 +-0.2 mGy for D R systems. Statistical analysis for differences in mean values of K i and D g between mammography systems showed significant effect of their technical characteristics (p i and D g , it was observed statistically significant differences between the group of patients with 0 to 50% glandularity and the group of patients with 50 to 100% glandularity. (author)

  10. Disruption mitigation experiment with massive gas injection of HT-7

    International Nuclear Information System (INIS)

    Zhuang Huidong; Zhang Xiaodong

    2013-01-01

    Massive gas injection (MGI) is a promising method on disruption mitigation. The working principle of the fast valve for disruption mitigation was introduced. The disruption mitigation experiments by MGI on HT-7 were described. The experiment shows that the impurities radiation is improved by injecting appropriate amount of gas, and the current quench rate is slow down, so the electromagnetic load on the device is mitigated. The experiments show that the fast valve can completely satisfy the requirement of disruption mitigation on HT-7. (authors)

  11. Analysis by Fourier Transform Infrared (FTIR) of the gamma radiation effect on epoxy resin, used as solidification agent of radioactive wastes

    International Nuclear Information System (INIS)

    Liu, C.H.; Riella, H.G.; Guedes, S.M.L.

    1995-01-01

    The effects of gamma radiation on Epoxy resin, used as solidification agent of radioactive wastes, were studied by Fourier Transform Infrared (FTIR). The spectra showed no significant modifications on Epoxy resin functional groups (irradiated with dose from 0 to 1 MGy). Up to 1 MGy Epoxy resin did not oxidize, confirming the Epoxy good radiation strength. The presence of aromatic chain and amine group, mainly tertiary amine, give good radiolytic stability to the Epoxy, increasing the interest to use this material in nuclear facilities. (author). 3 refs, 2 figs

  12. SU-E-P-08: Establishment of Local Diagnostic Reference Levels of Routine Abdomen Exam in Computed Tomography According to Body Weight

    International Nuclear Information System (INIS)

    Wang, H; Wang, Y; Weng, H

    2015-01-01

    Purpose: The national diagnostic reference levels (NDRLs) is an efficient, concise and powerful standard for optimizing radiation protection of a patient. However, for each hospital the dose-reducing potential of focusing on establishment of local DRLs (LDRLs). A lot of study reported that Computed tomography exam contributed majority radiation dose in different medical modalities, therefore, routine abdomen CT exam was choose in initial pilot study in our study. Besides the mAs of routine abdomen CT exam was decided automatic exposure control by linear attenuation is relate to body shape of patient. In this study we would like to establish the local diagnostic reference levels of routine abdomen exam in computed tomography according to body weight of patient. Methods and Materials: There are two clinical CT scanners (a Toshiba Aquilion and a Siemens Sensation) were performed in this study. For CT examinations the basic recommended dosimetric quantity is the Computed Tomography Dose Index (CTDI). The patient sample involved 82 adult patients of both sexes and divided into three groups by their body weight (50–60 kg, 60–70 kg, 70–80 kg).Carried out the routine abdomen examinations, and all exposure parameters have been collected and the corresponding CTDIv and DLP values have been determined. The average values were compared with the European DRLs. Results: The majority of patients (75%) were between 50–70 Kg of body weight, the numbers of patient in each group of weight were 40–50:7; 50–60:29; 60–70:33; 70–80:13. The LDRLs in each group were 10.81mGy, 14.46mGy, 20.27mGy and 21.04mGy, respectively. The DLP were 477mGy, 630mGy, 887mGy and 959mGy, respectively. No matter which group the LDRLs were lower than European DRLs. Conclusions: We would like to state that this was a pioneer work in local hospital in Chiayi. We hope that this may lead the way to further developments in Taiwan

  13. Entrance surface dose measurements in pediatric radiological examinations

    International Nuclear Information System (INIS)

    Ribeiro, L.A.; Yoshimura, E.M.

    2008-01-01

    A survey of pediatric radiological examinations was carried out in a reference pediatric hospital of the city of Sao Paulo, in order to investigate the doses to children undergoing conventional X-ray examinations. The results showed that the majority of pediatric patients are below 4 years, and that about 80% of the examinations correspond to chest projections. Doses to typical radiological examinations were measured in vivo with thermoluminescent dosimeters (LiF: Mg, Ti and LiF: Mg, Cu, P) attached to the skin of the children to determine entrance surface dose (ESD). Also homogeneous phantoms were used to obtain ESD to younger children, because the technique uses a so small kVp that the dosimeters would produce an artifact image in the patient radiograph. Four kinds of pediatric examinations were investigated: three conventional examinations (chest, skull and abdomen) and a fluoroscopic procedure (barium swallow). Relevant information about kVp and mAs values used in the examinations was collected, and we discuss how these parameters can affect the ESD. The ESD values measured in this work are compared to reference levels published by the European Commission for pediatric patients. The results obtained (third-quartile of the ESD distribution) for chest AP examinations in three age groups were: 0.056 mGy (2-4 years old); 0.068 mGy (5-9 years old); 0.069 mGy (10-15 years old). All of them are below the European reference level (0.100 mGy). ESD values measured to the older age group in skull and abdomen AP radiographs (mean values 3.44 and 1.20 mGy, respectively) are above the European reference levels (1.5 mGy to skull and 1.0 mGy to abdomen). ESD values measured in the barium swallow examination reached 10 mGy in skin regions corresponding to thyroid and esophagus. It was noticed during this survey that some technicians use, improperly, X-ray fluoroscopy in conventional examinations to help them in positioning the patient. The results presented here are a

  14. TH-AB-207A-03: Skin Dose to Patients Receiving Multiple CTA and CT Exams of the Head

    International Nuclear Information System (INIS)

    Nawfel, RD; Young, G

    2016-01-01

    Purpose: To measure patient skin dose from CT angiography (CTA) and CT exams of the head, and determine if patients having multiple exams could receive cumulative doses that approach or exceed deterministic thresholds. Methods: This study was HIPAA compliant and conducted with IRB approval. Patient skin doses were measured over a 4 month period using nanoDot OSL dosimeters placed on the head of 52 patients for two CT scanners. On each scanner, 26 patients received CT exams (scanner 1: 10 females, 16 males, mean age 64.2 years; scanner 2: 18 females, 8 males, mean age 61.2 years). CT exam dose metrics, CTDIvol and dose-length product (DLP) were recorded for each exam. Additionally, skin dose was measured on an acrylic skull phantom in each scanner and on a neuro-interventional imaging system using clinical protocols. Measured dose data was used to estimate peak skin dose (PSD) for 4 patients receiving multiple exams including CTA, head CT, and cerebral angiography. Results: For scanner 1, the mean PSD for CTA exams (98.9 ± 5.3 mGy) and for routine head CT exams (39.2 ± 3.7 mGy) agreed reasonably well with the PSD measured on the phantom, 105.4 mGy and 40.0 mGy, respectively. Similarly for scanner 2, the mean PSD for CTA exams (98.8 ± 7.4 mGy) and for routine head CT exams (42.9 ± 9.4 mGy) compared well with phantom measurements, 95.2 mGy and 37.6 mGy, respectively. In addition, the mean PSD was comparable between scanners for corresponding patient exams, CTA and routine head CT respectively. PSD estimates ranged from 1.9 – 4.5 Gy among 4 patients receiving multiple exams. Conclusion: Patients having several exams including both CTA and routine head CT may receive cumulative doses approaching or exceeding the threshold for single dose deterministic effects.

  15. Average glandular dose in digital mammography and breast tomosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Olgar, T. [Ankara Univ. (Turkey). Dept. of Engineering Physics; Universitaetsklinikum Leipzig AoeR (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie; Kahn, T.; Gosch, D. [Universitaetsklinikum Leipzig AoeR (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie

    2012-10-15

    Purpose: To determine the average glandular dose (AGD) in digital full-field mammography (2 D imaging mode) and in breast tomosynthesis (3 D imaging mode). Materials and Methods: Using the method described by Boone, the AGD was calculated from the exposure parameters of 2247 conventional 2 D mammograms and 984 mammograms in 3 D imaging mode of 641 patients examined with the digital mammographic system Hologic Selenia Dimensions. The breast glandular tissue content was estimated by the Hologic R2 Quantra automated volumetric breast density measurement tool for each patient from right craniocaudal (RCC) and left craniocaudal (LCC) images in 2 D imaging mode. Results: The mean compressed breast thickness (CBT) was 52.7 mm for craniocaudal (CC) and 56.0 mm for mediolateral oblique (MLO) views. The mean percentage of breast glandular tissue content was 18.0 % and 17.4 % for RCC and LCC projections, respectively. The mean AGD values in 2 D imaging mode per exposure for the standard breast were 1.57 mGy and 1.66 mGy, while the mean AGD values after correction for real breast composition were 1.82 mGy and 1.94 mGy for CC and MLO views, respectively. The mean AGD values in 3 D imaging mode per exposure for the standard breast were 2.19 mGy and 2.29 mGy, while the mean AGD values after correction for the real breast composition were 2.53 mGy and 2.63 mGy for CC and MLO views, respectively. No significant relationship was found between the AGD and CBT in 2 D imaging mode and a good correlation coefficient of 0.98 in 3 D imaging mode. Conclusion: In this study the mean calculated AGD per exposure in 3 D imaging mode was on average 34 % higher than for 2 D imaging mode for patients examined with the same CBT.

  16. Average glandular dose in digital mammography and breast tomosynthesis

    International Nuclear Information System (INIS)

    Olgar, T.; Universitaetsklinikum Leipzig AoeR; Kahn, T.; Gosch, D.

    2012-01-01

    Purpose: To determine the average glandular dose (AGD) in digital full-field mammography (2 D imaging mode) and in breast tomosynthesis (3 D imaging mode). Materials and Methods: Using the method described by Boone, the AGD was calculated from the exposure parameters of 2247 conventional 2 D mammograms and 984 mammograms in 3 D imaging mode of 641 patients examined with the digital mammographic system Hologic Selenia Dimensions. The breast glandular tissue content was estimated by the Hologic R2 Quantra automated volumetric breast density measurement tool for each patient from right craniocaudal (RCC) and left craniocaudal (LCC) images in 2 D imaging mode. Results: The mean compressed breast thickness (CBT) was 52.7 mm for craniocaudal (CC) and 56.0 mm for mediolateral oblique (MLO) views. The mean percentage of breast glandular tissue content was 18.0 % and 17.4 % for RCC and LCC projections, respectively. The mean AGD values in 2 D imaging mode per exposure for the standard breast were 1.57 mGy and 1.66 mGy, while the mean AGD values after correction for real breast composition were 1.82 mGy and 1.94 mGy for CC and MLO views, respectively. The mean AGD values in 3 D imaging mode per exposure for the standard breast were 2.19 mGy and 2.29 mGy, while the mean AGD values after correction for the real breast composition were 2.53 mGy and 2.63 mGy for CC and MLO views, respectively. No significant relationship was found between the AGD and CBT in 2 D imaging mode and a good correlation coefficient of 0.98 in 3 D imaging mode. Conclusion: In this study the mean calculated AGD per exposure in 3 D imaging mode was on average 34 % higher than for 2 D imaging mode for patients examined with the same CBT.

  17. Assessment of dedicated low-dose cardiac micro-CT reconstruction algorithms using the left ventricular volume of small rodents as a performance measure

    International Nuclear Information System (INIS)

    Maier, Joscha; Sawall, Stefan; Kachelrieß, Marc

    2014-01-01

    Purpose: Phase-correlated microcomputed tomography (micro-CT) imaging plays an important role in the assessment of mouse models of cardiovascular diseases and the determination of functional parameters as the left ventricular volume. As the current gold standard, the phase-correlated Feldkamp reconstruction (PCF), shows poor performance in case of low dose scans, more sophisticated reconstruction algorithms have been proposed to enable low-dose imaging. In this study, the authors focus on the McKinnon-Bates (MKB) algorithm, the low dose phase-correlated (LDPC) reconstruction, and the high-dimensional total variation minimization reconstruction (HDTV) and investigate their potential to accurately determine the left ventricular volume at different dose levels from 50 to 500 mGy. The results were verified in phantom studies of a five-dimensional (5D) mathematical mouse phantom. Methods: Micro-CT data of eight mice, each administered with an x-ray dose of 500 mGy, were acquired, retrospectively gated for cardiac and respiratory motion and reconstructed using PCF, MKB, LDPC, and HDTV. Dose levels down to 50 mGy were simulated by using only a fraction of the projections. Contrast-to-noise ratio (CNR) was evaluated as a measure of image quality. Left ventricular volume was determined using different segmentation algorithms (Otsu, level sets, region growing). Forward projections of the 5D mouse phantom were performed to simulate a micro-CT scan. The simulated data were processed the same way as the real mouse data sets. Results: Compared to the conventional PCF reconstruction, the MKB, LDPC, and HDTV algorithm yield images of increased quality in terms of CNR. While the MKB reconstruction only provides small improvements, a significant increase of the CNR is observed in LDPC and HDTV reconstructions. The phantom studies demonstrate that left ventricular volumes can be determined accurately at 500 mGy. For lower dose levels which were simulated for real mouse data sets, the

  18. Assessment of dedicated low-dose cardiac micro-CT reconstruction algorithms using the left ventricular volume of small rodents as a performance measure.

    Science.gov (United States)

    Maier, Joscha; Sawall, Stefan; Kachelrieß, Marc

    2014-05-01

    Phase-correlated microcomputed tomography (micro-CT) imaging plays an important role in the assessment of mouse models of cardiovascular diseases and the determination of functional parameters as the left ventricular volume. As the current gold standard, the phase-correlated Feldkamp reconstruction (PCF), shows poor performance in case of low dose scans, more sophisticated reconstruction algorithms have been proposed to enable low-dose imaging. In this study, the authors focus on the McKinnon-Bates (MKB) algorithm, the low dose phase-correlated (LDPC) reconstruction, and the high-dimensional total variation minimization reconstruction (HDTV) and investigate their potential to accurately determine the left ventricular volume at different dose levels from 50 to 500 mGy. The results were verified in phantom studies of a five-dimensional (5D) mathematical mouse phantom. Micro-CT data of eight mice, each administered with an x-ray dose of 500 mGy, were acquired, retrospectively gated for cardiac and respiratory motion and reconstructed using PCF, MKB, LDPC, and HDTV. Dose levels down to 50 mGy were simulated by using only a fraction of the projections. Contrast-to-noise ratio (CNR) was evaluated as a measure of image quality. Left ventricular volume was determined using different segmentation algorithms (Otsu, level sets, region growing). Forward projections of the 5D mouse phantom were performed to simulate a micro-CT scan. The simulated data were processed the same way as the real mouse data sets. Compared to the conventional PCF reconstruction, the MKB, LDPC, and HDTV algorithm yield images of increased quality in terms of CNR. While the MKB reconstruction only provides small improvements, a significant increase of the CNR is observed in LDPC and HDTV reconstructions. The phantom studies demonstrate that left ventricular volumes can be determined accurately at 500 mGy. For lower dose levels which were simulated for real mouse data sets, the HDTV algorithm shows the

  19. Assessment of dedicated low-dose cardiac micro-CT reconstruction algorithms using the left ventricular volume of small rodents as a performance measure

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Joscha, E-mail: joscha.maier@dkfz.de [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Sawall, Stefan; Kachelrieß, Marc [Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany and Institute of Medical Physics, University of Erlangen–Nürnberg, 91052 Erlangen (Germany)

    2014-05-15

    Purpose: Phase-correlated microcomputed tomography (micro-CT) imaging plays an important role in the assessment of mouse models of cardiovascular diseases and the determination of functional parameters as the left ventricular volume. As the current gold standard, the phase-correlated Feldkamp reconstruction (PCF), shows poor performance in case of low dose scans, more sophisticated reconstruction algorithms have been proposed to enable low-dose imaging. In this study, the authors focus on the McKinnon-Bates (MKB) algorithm, the low dose phase-correlated (LDPC) reconstruction, and the high-dimensional total variation minimization reconstruction (HDTV) and investigate their potential to accurately determine the left ventricular volume at different dose levels from 50 to 500 mGy. The results were verified in phantom studies of a five-dimensional (5D) mathematical mouse phantom. Methods: Micro-CT data of eight mice, each administered with an x-ray dose of 500 mGy, were acquired, retrospectively gated for cardiac and respiratory motion and reconstructed using PCF, MKB, LDPC, and HDTV. Dose levels down to 50 mGy were simulated by using only a fraction of the projections. Contrast-to-noise ratio (CNR) was evaluated as a measure of image quality. Left ventricular volume was determined using different segmentation algorithms (Otsu, level sets, region growing). Forward projections of the 5D mouse phantom were performed to simulate a micro-CT scan. The simulated data were processed the same way as the real mouse data sets. Results: Compared to the conventional PCF reconstruction, the MKB, LDPC, and HDTV algorithm yield images of increased quality in terms of CNR. While the MKB reconstruction only provides small improvements, a significant increase of the CNR is observed in LDPC and HDTV reconstructions. The phantom studies demonstrate that left ventricular volumes can be determined accurately at 500 mGy. For lower dose levels which were simulated for real mouse data sets, the

  20. Risk and benefit associated with preventive mammography examinations

    International Nuclear Information System (INIS)

    Vladar, M.; Nikodemova, D.

    1998-01-01

    The risk of mammographic examination was estimated. It is concluded that a mean glandular dose (MGD) of 1 mGy per exposure can be associated with a risk of 1 radiation-induced carcinoma per less than 100 positive detected by the preventive examination. The variability of actual MGD at various hospitals can be quite large. Although the majority of measurements were made on phantoms it is assumed that the national MGD average will exceed 3 mGy for the average breast size of 55 mm

  1. Dose levels in conventional X-rays

    International Nuclear Information System (INIS)

    Guerra M, J. A.; Gonzalez G, J. A.; Pinedo S, A.; Salas L, M. A.; Vega C, H. R.; Rivera M, T.; Azorin N, J.

    2009-10-01

    There were a series of measures in the General Hospital of Fresnillo in the X-ray Department in the areas of X-1 and X-2-ray rooms and in the neonatal intensive care unit 2, was determined the dose surface entry in eyes, thyroid and gonads for patients undergoing to X-ray study of chest Tele by thermoluminescent dosimetry. Five dosemeters were used in each one of the scans; so find the following dose ranges 20 + - 23 mGy to 350 + - 41 mGy. With the results obtained we can conclude that the procedures used and the equipment calibration is adequate. (Author)

  2. Computed Tomography (CT) radiation dose in children: A survey to propose regional diagnostic reference levels in Greater Accra-Ghana

    International Nuclear Information System (INIS)

    Addo, Patience

    2016-07-01

    The aim of this work was to assess the doses delivered to paediatric patients during computed tomography (CT) examinations of the head, chest and abdomen, and establishing regional diagnostic reference levels (RDRLs) for four age groups. The patient data, technique parameters and dose descriptors collected include: age, sex, tube voltage, tube current, rotation time, slice thickness, scan length, volume CT dose index (CTDI_v_o_l) and dose length product (DLP). Currently, paediatric CT examinations account for 11% of radiation exposure. For the paediatric age groups; < 1 year, (1-5 years), (6-10 years) and (11-15 years), the proposed RDRLs for head in terms of CTDI_v_o_l are (28, 38, 48 and 86 mGy) and in terms of DLP; (395, 487, 601, 1614 mGy cm) respectively. For Chest examinations, proposed RDRLs in terms of CTDI_v_o_l are (1 and 5 mGy) and in terms of DLP; (18 and 110 mGy cm) for age groups; < 1 year and (1-5 years) respectively. For Abdomino-pelvic examinations, proposed RDRLs in terms of CTDI_v_o_l are (3, 3 and 10 mGy) and in terms of DLP; (71, 120 and 494 mGy cm) for age groups; < 1 year, (1-5 years) and (6-10 years) respectively. For abdomen examinations, proposed RDRLs in terms of CTDI_v_o_l are (3, 5 and 5 mGy) and in terms of DLP; (83, 124 and 233 mGy cm) for age groups; < 1 year, (1-5 years) and (11-15 years) respectively. RDRLs have been proposed for CTDI_v_o_l and DLP for head, chest, abdomen and Abdomino-pelvic paediatric CT examinations in this study. An optimisation is required for 11-15 years age group for the DLP values which was higher than their corresponding international DRLs. For an effective optimization of patient protection a trade-off between image quality and patients doses studies should be investigated. (au)

  3. Anti-tumor effect of low dose radiation in mice

    International Nuclear Information System (INIS)

    Fan Zhengping; Lu Jiaben; Zhu Bingchai

    1997-01-01

    The author reports the effects of the total body irradiation of low dose radiation (LDR) and/or the local irradiation of large dose on average tumor weights and tumor inhibitory rates in 170 mice inoculated S 180 sarcoma cell, and the influence of LDR on average longevity in 40 tumor-bearing animals. Results show (1) LDR in the range of 75∼250 mGy can inhibit tumor growth to some extent; (2) fractionated irradiation of 75 mGy and local irradiation of 10 Gy may produce a synergism in tumor growth inhibition; and (3)LDR may enhance average longevity in ascitic tumor-bearing mice

  4. Thermogravimetric study of γ-irradiated lanthanum oxalate

    International Nuclear Information System (INIS)

    Nayak, H.; Bhatta, D.

    2000-01-01

    Thermogravimetric study of La 2 (C 2 O 4 ) 3 , exposed to different doses (5.0 - 50.0 x 10 -2 MGy) of γ-rays has been carried out. Marginal effect is observed at lower doses which is prominent at higher dose (5.0 x 10 -1 MGy). The radiolytic damaged entities, generated by irradiation favours the reaction by creating new potential nucleation centres in the lattice. The solid product, La 2 O 3 formed by irradiation also acts as a heterogeneous catalyst and brings out changes in the reactivity of the solid. (author)

  5. SU-E-P-08: Establishment of Local Diagnostic Reference Levels of Routine Abdomen Exam in Computed Tomography According to Body Weight

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H; Wang, Y; Weng, H [Chiayi Chang Gung Memorial Hospital of The C.G.M.F, Puzi City, Chiayi County, Taiwan (China)

    2015-06-15

    Purpose: The national diagnostic reference levels (NDRLs) is an efficient, concise and powerful standard for optimizing radiation protection of a patient. However, for each hospital the dose-reducing potential of focusing on establishment of local DRLs (LDRLs). A lot of study reported that Computed tomography exam contributed majority radiation dose in different medical modalities, therefore, routine abdomen CT exam was choose in initial pilot study in our study. Besides the mAs of routine abdomen CT exam was decided automatic exposure control by linear attenuation is relate to body shape of patient. In this study we would like to establish the local diagnostic reference levels of routine abdomen exam in computed tomography according to body weight of patient. Methods and Materials: There are two clinical CT scanners (a Toshiba Aquilion and a Siemens Sensation) were performed in this study. For CT examinations the basic recommended dosimetric quantity is the Computed Tomography Dose Index (CTDI). The patient sample involved 82 adult patients of both sexes and divided into three groups by their body weight (50–60 kg, 60–70 kg, 70–80 kg).Carried out the routine abdomen examinations, and all exposure parameters have been collected and the corresponding CTDIv and DLP values have been determined. The average values were compared with the European DRLs. Results: The majority of patients (75%) were between 50–70 Kg of body weight, the numbers of patient in each group of weight were 40–50:7; 50–60:29; 60–70:33; 70–80:13. The LDRLs in each group were 10.81mGy, 14.46mGy, 20.27mGy and 21.04mGy, respectively. The DLP were 477mGy, 630mGy, 887mGy and 959mGy, respectively. No matter which group the LDRLs were lower than European DRLs. Conclusions: We would like to state that this was a pioneer work in local hospital in Chiayi. We hope that this may lead the way to further developments in Taiwan.

  6. Summary of round robin measurements of radiation induced conductivity in Wesgo AL995 alumina

    Energy Technology Data Exchange (ETDEWEB)

    Zinkle, S.J. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    This existing data on radiation induced conductivity (RIC) measurements performed on the same heat of the IEA reference ceramic insulator are summarized. Six different sets of RIC measurements have been performed on Wesgo AL995 at dose rates between 10 Gy/s and 1 MGy/s. In general, good agreement was obtained between the different groups of researchers. The data indicate that the RIC at a test temperature of 400-500{degrees}C is approximately linear with ionizing dose rate up to {approximately}1000 Gy/s, and exhibits an approximately square root dependence on dose rate between 1 kGy/s and 1 MGy/s.

  7. TH-AB-207A-03: Skin Dose to Patients Receiving Multiple CTA and CT Exams of the Head

    Energy Technology Data Exchange (ETDEWEB)

    Nawfel, RD; Young, G [Brigham & Women’s Hospital, Boston, MA (United States)

    2016-06-15

    Purpose: To measure patient skin dose from CT angiography (CTA) and CT exams of the head, and determine if patients having multiple exams could receive cumulative doses that approach or exceed deterministic thresholds. Methods: This study was HIPAA compliant and conducted with IRB approval. Patient skin doses were measured over a 4 month period using nanoDot OSL dosimeters placed on the head of 52 patients for two CT scanners. On each scanner, 26 patients received CT exams (scanner 1: 10 females, 16 males, mean age 64.2 years; scanner 2: 18 females, 8 males, mean age 61.2 years). CT exam dose metrics, CTDIvol and dose-length product (DLP) were recorded for each exam. Additionally, skin dose was measured on an acrylic skull phantom in each scanner and on a neuro-interventional imaging system using clinical protocols. Measured dose data was used to estimate peak skin dose (PSD) for 4 patients receiving multiple exams including CTA, head CT, and cerebral angiography. Results: For scanner 1, the mean PSD for CTA exams (98.9 ± 5.3 mGy) and for routine head CT exams (39.2 ± 3.7 mGy) agreed reasonably well with the PSD measured on the phantom, 105.4 mGy and 40.0 mGy, respectively. Similarly for scanner 2, the mean PSD for CTA exams (98.8 ± 7.4 mGy) and for routine head CT exams (42.9 ± 9.4 mGy) compared well with phantom measurements, 95.2 mGy and 37.6 mGy, respectively. In addition, the mean PSD was comparable between scanners for corresponding patient exams, CTA and routine head CT respectively. PSD estimates ranged from 1.9 – 4.5 Gy among 4 patients receiving multiple exams. Conclusion: Patients having several exams including both CTA and routine head CT may receive cumulative doses approaching or exceeding the threshold for single dose deterministic effects.

  8. Patient dosimetry during chest radiography

    International Nuclear Information System (INIS)

    Ciraj-Bjelac, O.; Kosutic, D.; Markovic, S.

    2004-01-01

    Reasons for the variation in patient doses from chest radiography procedure were investigated by assessing entrance skin doses from kerma-area product measurements. Data were collected from seven x-ray tubes in five hospitals involving 259 adult patients. The third quartile value was 0.81 mGy compared to general reference level of 0.30 mGy. The applied tube potential was main contributor to patient dose variation. If department use at least 90 k Vp, the mean entrance surface dose would be reduced ut to factor six. Modification of departmental procedure is correct approach for dose reduction in diagnostic radiology. (author) [sr

  9. Evaluation of usability of the shielding effect for thyroid shield for peripheral dose during whole brain radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Myung Sic; Park, Ju Kyeong; Lee, Seung Hun; Kim, Yang Su; Lee, Sun Young; Cha, Seok Yong [Dept. of Radiation Oncology, Chonbuk National University Hospital, Jeonju (Korea, Republic of)

    2014-12-15

    To reduce the radiation dose to the thyroid that is affected to scattered radiation, the shield was used. And we evaluated the shielding effect for the thyroid during whole brain radiation therapy. To measure the dose of the thyroid, 300cGy were delivered to the phantom using a linear accelerator(Clinac iX VARIAN, USA.)in the way of the 6MV X-ray in bilateral. To measure the entrance surface dose of the thyroid, five glass dosimeters were placed in the 10th slice's surface of the phantom with a 1.5 cm interval. The average values were calculated by measured values in five times each, using bismuth shield, 0.5 mmPb shield, self-made 1.0 mmPb shield and unshield. In the same location, to measure the depth dose of the thyroid, five glass dosimeters were placed in the 10th slice by 2.5 cm depth of the phantom with a 1.5 cm interval. The average values were calculated by measured values in five times each, using bismuth shield, 0.5 mmPb shield, self-made 1.0 mmPb shield and unshield. Entrance surface dose of the thyroid were respectively 44.89 mGy at the unshield, 36.03 mGy at the bismuth shield, 31.03 mGy at the 0.5 mmPb shield and 23.21 mGy at a self-made 1.0 mmPb shield. In addition, the depth dose of the thyroid were respectively 36.10 mGy at the unshield, 34.52 mGy at the bismuth shield, 32.28 mGy at the 0.5 mmPb shield and 25.50 mGy at a self-made 1.0 mmPb shield. The thyroid was affected by the secondary scattering dose and leakage dose outside of the radiation field during whole brain radiation therapy. When using a shield in the thyroid, the depth dose of thyroid showed 11-30% reduction effect and the surface dose of thyroid showed 20-48% reduction effect. Therefore, by using the thyroid shield, it is considered to effectively protect the thyroid and can perform the treatment.

  10. Optimization of the Radiological Protection of Patients in Diagnostic Radiology Department at Kenyatta National Hospital in Kenya

    International Nuclear Information System (INIS)

    Korir, G.K.; Ochieng, B.O.M; Wambani, J. S.

    2008-01-01

    The use of ionizing radiation in the medical field accounts for the largest contribution of radiation exposure to man. Use of ionizing radiation requires a careful balance of risks and benefits due to the somatic and hereditary which are well known to have no threshold level due to the random nature of radiation. The radiation doses received by patients undergoing radiographic examinations were measured in 189 randomly selected patients from three different x-ray rooms at a referral, teaching and research hospital in Kenya. The exercise was done on 54 pediatric and 135 adult patients during the screening period between October and November 2005. The entrance surface dose (ESD) to the patients undergoing each of these procedures was measured using LiF-100 thermoluminescent dosimeters (TLDs). The values obtained ranged from 0.33 mGy to 143 mGy for adult patients and 0.12 mGy to 4.32 mGy for pediatric patients. The mean values were found to be 8.44 mGy, 11.16 mGy and 1.44 mGy for rooms A, B and C respectively. The hospital's average dose stood at 7.01 mGy. The mean patient thickness for adults in cm were 19.5 for chest PA/AP, 28 chest LAT, 27 lumbar sacral, 28 lumbar spine AP, 30 lumbar spine LAT and for children 9.5 chest AP, 19.5 chest LAT, 8 post nasal space (PNS) 11.5 lumbar spine AP and 15 for lumbar spine LAT. Adult ages averaged at 35 years and less than 15 years old for sensitive to gamma rathe ESD in most procedures in adults were found to exceed the International ESD reference levels. However, it should be noted that so far guidance levels (GL) for children do not exist. The x-ray units were tested for quality control performance. They failed with respect to kVp accuracy, focal spot size and total filtration tests. From the Radiologists image quality assessment of the radiographs, 52% were awarded grade A, 40% grade B and 8% grade C. Film rejection analysis was measured to be 14% in overall. The following were the major causes; positioning, underexposure and

  11. DNA alterations and effects on growth and reproduction in Daphnia magna during chronic exposure to gamma radiation over three successive generations

    Energy Technology Data Exchange (ETDEWEB)

    Parisot, Florian [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, St Paul-lez-Durance 13115 (France); Bourdineaud, Jean-Paul [UMR 5805 EPOC – OASU, Station marine d’Arcachon, Université Bordeaux 1, Arcachon 33120 (France); Plaire, Delphine; Adam-Guillermin, Christelle [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, St Paul-lez-Durance 13115 (France); Alonzo, Frédéric, E-mail: frederic.alonzo@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, St Paul-lez-Durance 13115 (France)

    2015-06-15

    Highlights: • We exposed three successive generations of Daphnia magna to chronic gamma radiation. • We examined DNA alterations and effects on survival, growth and reproduction. • DNA alterations were accumulated over a generation and transmitted to the progeny. • Effects on survival and reproduction, and delay in growth increased over generations. - Abstract: This study examined chronic effects of external Cs-137 gamma radiation on Daphnia magna exposed over three successive generations (F0, F1 and F2) to environmentally relevant dose rates (ranging from 0.007 to 35.4 mGy h{sup −1}). Investigated endpoints included survival, growth, reproduction and DNA alterations quantified using random-amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). Results demonstrated that radiation effects on survival, growth and reproduction increased in severity from generation F0 to generation F2. Mortality after 21 days at 35.4 mGy h{sup −1} increased from 20% in F0 to 30% in F2. Growth was affected by a slight reduction in maximum length at 35.4 mGy h{sup −1} in F0 and by reductions of 5 and 13% in growth rate, respectively, at 4.70 and 35.4 mGy h{sup −1} in F2. Reproduction was affected by a reduction of 19% in 21 day-fecundity at 35.4 mGy h{sup −1} in F0 and by a delay of 1.9 days in brood release as low as 0.070 mGy h{sup −1} in F2. In parallel, DNA alterations became significant at decreasing dose rates over the course of F0 (from 4.70 mGy h{sup −1} at hatching to 0.007 mGy h{sup −1} after ∼21 days) and from F0 to F2 (0.070 mGy h{sup −1} at hatching to 0.007 mGy h{sup −1} after ∼21 days), demonstrating their rapid accumulation in F0 daphnids and their transmission to offspring generations. Transiently more efficient DNA repair leading to some recovery at the organism level was suggested in F1, with no effect on survival, a slight reduction of 12% in 21 day-fecundity at 35.4 mGy h{sup −1} and DNA alterations significant at highest

  12. A cytogenetic study on persons exposed to 241Am-Be neutron source

    International Nuclear Information System (INIS)

    Bai Yushu; Zhang Xiuxia; Guan Shurong; Xie Feng; Lu Meiying

    1988-01-01

    An 241 Am-Be neutron source of 120 millicrocurie was stolen by a boy on April the 3rd, 1982. He brought it to his home. The neutron source was broken and the radioactive substance contaminated the whole family. He and his other family members did not leave the contaminated environment for 70 days. There were altogether 14 persons exposed to the radioactive substances. Chromosome aberrations of peripheral blood lymphocytes of six exposed cases were analysed on an early day of June 1982. The exposure doses were estimated by the frequency of chromosome aberration. Biological dose absorbed by the boy who stole the source was about 96 ∼ 128 mGy (physical dose about 120 mGy), the others were about 10 ∼ 30 mGy (physical dose about 10 ∼ 30 mGy). The results indicated that biological dose were quite approximate to the physical doses. One and half years after the accident, the analysis of stable chromosome aberrations for 14 exposed persons showed that the frequencies of chromosome aberrations of the irradiated individuals were still higher than those of the controls. The differences between them are very significant

  13. Evaluation of doses in conventional radiology in the cities of Rio de Janeiro e Recife, Brazil

    International Nuclear Information System (INIS)

    Azevedo, Ana Cecilia P.; Osibote, Adelaja O.; Khoury, Helen J.

    2005-01-01

    This work is part of a program of evaluating doses in patients developed in several hospitals in the States of Rio de Janeiro and Pernambuco. We used the program DoseCal to evaluate the Input Skin Dose (DEP) and the Effective Dose (DE) in big public hospitals in the cities of Rio de Janeiro and Recife. It were included in the survey the doses of chest radiographs, cervical spine, lumbar spine, skull and pelvis in the projections AP, PA and LAT. To chest in PA the average value of DEP for the hospital A was 0.19 mGy. For to hospital B was 0.07 mGy. For the exam of the skull in PA the average value in A was 3.25 mGy and B of 0.49 mGy. With respect to radiological techniques might be noted that in most cases the hospital A used kilovoltage lower than in B and miliamperes higher. This can be one of the explanations for the difference of the values found for DEP and DE. The results showed significant discrepancies in values of doses as radiographic techniques when compared to the requirements established by the European Community for X-rays with image quality. This result is due to several factors: filtration, radiographic technique, professional technical experience and performance of radiographic equipment

  14. Crystal growth and thermoluminescence response of NaZr{sub 2}(PO{sub 4}){sub 3} at high gamma radiation doses

    Energy Technology Data Exchange (ETDEWEB)

    Ordóñez-Regil, E., E-mail: eduardo.ordonez@inin.gob.mx [Depto. de Química, Gerencia de Ciencias Básicas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); Contreras-Ramírez, A., E-mail: aida.contreras@inin.gob.mx [Depto. de Química, Gerencia de Ciencias Básicas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); Depto. de Tecnología de Materiales, Gerencia de Ciencias Aplicadas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); Facultad de Ciencias, Universidad Autónoma del Estado de México, Unidad Académica el Cerrillo, Piedras Blancas, AP 2-139, CP 50000 Toluca Estado de México (Mexico); Fernández-Valverde, S.M., E-mail: suilma.fernandez@inin.gob.mx [Depto. de Química, Gerencia de Ciencias Básicas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); González-Martínez, P.R., E-mail: pedro.gonzalez@inin.gob.mx [Depto. de Física, Gerencia de Ciencias Básicas, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico); Carrasco-Ábrego, H., E-mail: hector.carrasco@inin.gob.mx [Depto. Aceleradores, Gerencia de Ciencias Ambientales, Instituto Nacional de Investigaciones Nucleares, AP 18-1027, CP 11801 México D.F. (Mexico)

    2013-11-15

    Graphical abstract: -- Highlights: •NaZr{sub 2}(PO{sub 4}){sub 3} exposed to gamma doses of 10, 30 and 50 MGy. •Gamma radiation produced growth of the crystal size of the NZP. •Morphology changes were reversible by heating. •Linear relationship between the thermoluminescence and the applied gamma dose. •This property could be useful for high-level gamma dosimetry. -- Abstract: This work describes the synthesis and characterization of NaZr{sub 2}(PO{sub 4}){sub 3}. The stability of this material under high doses of gamma radiation was investigated in the range of 10–50 MGy. Samples of unaltered and gamma irradiated NaZr{sub 2}(PO{sub 4}){sub 3} were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermoluminescence. The results showed that while functional groups were not affected by the gamma irradiation, morphology changes were observed with increasing doses of gamma irradiation. The morphology of the non-irradiated compound is agglomerated flakes; however, irradiation at 10 MGy splits the flakes inducing the formation of well-defined cubes. Gamma irradiation induced the crystal size of the NaZr{sub 2}(PO{sub 4}){sub 3} to grow. The heat treatment (973 K) of samples irradiated at 50 MGy resulted in the recovery of the original morphology. Furthermore, the thermoluminescence analysis of the irradiated compound is reported.

  15. Assessment of patient dose and radiogenic risks during endoscopic retrograde cholangiopancreatography

    Energy Technology Data Exchange (ETDEWEB)

    Sulieman, A.; Elzaki, M. [Sudan University of Science and Technology, College of Medical Radiologic Science, P. O. Box 1908, Khartoum 11111 (Sudan); Alkhorayef, M.; Babikir, E. [King Saud University, College of Applied Sciences, Radiological Sciences Department, P. O. Box 10219, Riyadh 11433 (Saudi Arabia); Abuzaid, M. [University of Sharjah, College of Health Sciences, Medical Diagnostic Imaging Department, Sharjah (United Arab Emirates); Dalton, A.; Bradley, D., E-mail: Abdelmoneim_a@yahoo.com [University of Surrey, Centre for Nuclear and Radiation Physics, Department of Physics, GU2-7XH, Guildford, Surrey (United Kingdom)

    2015-10-15

    Endoscopic retrograde cholangiopancreatography (ERCP) is an invasive technique that has been used for over 30 years in the diagnosis and management of pancreaticobiliary disorders. The objectives of this study were to evaluate the patient entrance surface air kerma doses (ESAK) and estimate the organ and effective doses during ERCP in three hospitals in Khartoum. A total of 55 patients were examined in three hospitals in Khartoum state, Sudan. Calibrated thermoluminescence dosimeters (TLD)-Gr-200-A)) were used to measure patients ESAK. The overall mean of ESAK for all ERCP procedures was 42.4 mGy. The mean patient ESAK in Fedail, Soba and Ibn sena centers were 26.7 mGy, 26.0 mGy, 72.4 mGy, respectively. The effective doses in three centers were 1.6, 1.56 and 2.67 mSv in that order and the overall mean effective dose was 2.01 mSv. Patient radiation doses vary widely among the different hospitals. Patient ESAK is low compared to previous studies in the light of the current practice. Patient dose was decreased significantly in the last two decades. (Author)

  16. Enhancing anaerobic treatment of wastewaters containing oleic acid

    NARCIS (Netherlands)

    Hwu, C.S.

    1997-01-01

    INTRODUCTION

    Lipids are one of the major organic pollutants in municipal and industrial wastewaters. Although domestic sewage typically contains about 40-100 mg/I lipids (Forster, 1992; Quéméneur and Marty, 1994), it is industrial wastewaters that are of greater

  17. Non-LTE profiles of strong solar lines

    Science.gov (United States)

    Schneeberger, T. J.; Beebe, H. A.

    1976-01-01

    The complete linearization method is applied to the formation of strong lines in the solar atmosphere. Transitions in Na(I), Mg(I), Ca(I), Mg(II), and Ca(II) are computed with a standard atmosphere and microturbulent velocity model. The computed profiles are compared to observations at disk center.

  18. Study of an optimization protocol for radiographic techniques in computerized radiology; Estudo de um protocolo de otimizacao para as tecnicas radiograficas em radiologia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Abrantes, Marcos Eugenio Silva

    2015-07-01

    This work is designed to produce information for the improvement of image quality to deployment in a radiology department based on previous reviews of the images by questionnaires of acceptance and quality e recognition of the parameters used in chest radiographic techniques. The data collected were divided by male, female, PA and LAT thickness, body mass index, biotypes, anthropomorphic parameters and body evaluation associated with constant voltage and the additional filtration. The results show the predominance of 35 and 40 constants with additional filtration from 0.5 to 1.5 mmAl, voltage in male: (PA and LAT) 86-92 kV and 96-112 kV, female: 85-98 kV and 96-112 kV. The charge applied to the tube for males: (PA and LAT) 5-10 mA.s and 5-16 mA.s, female: (PA and LAT) 6.3-8 mA.s and 9-14 mA.s. Absorbed doses for males: (PA and PF) 0.04-0.17 mGy and 0.03-0.19 mGy and from female (PA and PF) from 0.03-0.22 mGy and 0, 04-0.17 mGy. This procedure can be used in radiology department to implement and acceptance in the quality of images. (author)

  19. Radiation dose estimation by tooth enamel EPR dosimetry for residents of Dolon and Bodene

    International Nuclear Information System (INIS)

    Zhumadilov, Kassym; Ivannikov, Alexander; Apsalikov, Kazbek N.

    2006-01-01

    The method of electron paramagnetic resonance (EPR) dosimetry was applied to the enamel of the teeth extracted from the residents of the Dolon and Bodene settlements of the Beskaragay district, which is the area adjacent to the radioactive fallout of the most contaminating nuclear test of 1949. The individual accidental radiation doses due to the fallout were obtained from the amplitude of the radiation induced EPR signal from the CO 2- radical using the calibration method, after determining the parameters of EPR measurements to obtain the best reproducibility of the signal intensities. It was shown that after subtracting the natural background dose from the total absorbed dose obtained by EPR the residents of Dolon and Bodene received accidental radiation doses up to 356 mGy with an average value of 74.1 ± 45.5 mGy before 1949 while the younger population received up to about 100 mGy with an average value of 11.5 ± 37.7 mGy. (author)

  20. The Impact of Low Level X-rays on Biosynthesis of Gold Nanoparticles by Actinobacteria

    Directory of Open Access Journals (Sweden)

    Faranak Saghatchi

    2016-12-01

    Full Text Available Background: Gold nanoparticles (GNPs play an important role in medical, health and environmental applications. All kinds of microorganisms were found to be able to synthesize GNPs. The optimization of laboratory conditions for achieving more economical benefits of mass production has been studied widely. Methods: This study assesses the enhancing effect of low-level X-rays on the biosynthesis of GNPs by Actinomycetals. The isolated Actinomycetes were grown aerobically in MGYP broth media. The harvested bacteria were suspended in 50 mL aqueous HAuCl4 in 12 Erlenmeyer flask. Each group contained4 flasks. 2 groups of samples were irradiated by 30 mGy and 5 mGy X-rays respectively. The third group as control remained without irradiation. The solutions were shake- incubated for 120 h. Results: After 5 days, the color of first group samples changed from milky to purple, while the color changing occurred after 10 days in the 2nd group samples and the control samples. The UV-vis absorption spectrometry of the irradiated aqueous medium by 30 mGy X-rays confirmed the formation of GNPs. Conclusion: The findings showed that 30 mGy X-rays stimulated the microorganism to form GNPs in a half time in comparison to other groups.

  1. Diagnostic radiation and pregnancy

    International Nuclear Information System (INIS)

    Collins, L.; Fitzgerald, P.

    1983-01-01

    Accidental irradiation of the embryo or fetus in the first trimester is a problem which will occasionally occur. The value of a proper estimation of the radiation dose is emphasised. Very rarely does a single diagnostic procedure result in a uterine dose as high as 50 mGy. An accidental irradiation should rarely be cause for termination of a pregnancy

  2. Pilot survey of patient dose from computed tomography in Bulgaria

    International Nuclear Information System (INIS)

    Vassileva, Jenia; Stoyanov, Desislav

    2008-01-01

    The number of computed tomography (CT) scanners in Bulgaria increased from 22 in 1996 to more than 160 in 2007. Big variety of scanners of different manufacturers and different generations exists in the country with predominant number of single-slice scanners. Significant part of the scanners is more than 10 years old. This work presents the pilot results from the measurements of CT dose quantities started in 2005 with the aim to spread them to a national survey of CT practice in the country. It was found that different clinical protocols are used for similar examination, resulting in large variations in dose quantities: CT air kerma index varied from 27.1 to 78.4 mGy for head examination, from 8.7 to 28.3 mGy for chest, 11.8 - 30.7 mGy for abdomen and 9.1 - 41.3 mGy for pelvis. The CT air kerma-length product for complete examination was found to vary from 310 to 1254 mGy.cm for head examination, from 215 to 893 mGy.cm for chest, from 265 to 615 mGy.cm for abdomen and from 220 to 761 mGy.cm for pelvis. The analysis demonstrated that the main reasons for found variations are differences in scanning geometry, beam quality, exposure parameters and scanning length. (author)

  3. The influence of the Lop Nor Nuclear Weapons Test Base to the population of the Republic of Kazakhstan

    Energy Technology Data Exchange (ETDEWEB)

    Zhumadilov, Kassym, E-mail: kassym@hiroshima-u.ac.j [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553 (Japan); Ivannikov, Alexander [Medical Radiological Research Center, Korolev str. 4, Obninsk 249036 (Russian Federation); Zharlyganova, Dinara [Astana Medical University, Astana 010000 (Kazakhstan); Stepanenko, Valeriy [Medical Radiological Research Center, Korolev str. 4, Obninsk 249036 (Russian Federation); Zhumadilov, Zhaxybay [Nazarbayev University, Life Science Center, Astana 010000 (Kazakhstan); Apsalikov, Kazbek [Kazakh Scientific-Research Institute for Radiation Medicine and Ecology, Semey 071400 (Kazakhstan); Toyoda, Shin [Department of Applied Physics, Faculty of Science, Okayama University of Science, 1-1 Ridai, Okayama 700-0005 (Japan); Endo, Satoru [Department of Quantum Energy Applications, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527 (Japan); Tanaka, Kenichi [Division of Physics, Department of Liberal Arts and Sciences, Center of Medical Education, Sapporo Medical University, South 1, West 17, Chuo-ku, Sapporo 060-8556 (Japan); Miyazawa, Chuzou [School of Dentistry, Ohu University, 31-1, Aza-Misumido, Tomita-machi, Koriyama-shi, Fukushima Pref. 963-8611 (Japan); Okamoto, Tetsuji [Department of Molecular Oral Medicine and Maxillofacial Surgery, Division of Frontier Medical Sciences, Graduate School of Biomedical Sciences, Hiroshima University (Japan); Hoshi, Masaharu [Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8553 (Japan)

    2011-04-15

    The method of electron spin resonance (ESR) dosimetry was applied to human tooth enamel to obtain estimates of individual absorbed dose for residents of Makanchi, Urdzhar and Taskesken settlements located near the Kazakhstan-Chinese border (about 400 km to the South-East, from the Semipalatinsk Nuclear Test Site (SNTS) and about 1000 km from the Lop Nor Nuclear Weapons Test Base, China). Since the ground and atmospheric nuclear tests (1964-1981) at Lop Nor, the people residing in these settlements are believed to have been heavily exposed to radioactive fallout. Tooth samples had been extracted for medical reasons during the course of ordinary dental treatment. The village of Kokpekty, located 400 km to the South-east of the SNTS, was chosen as the control group since it has not been subjected to any radioactive contamination. The mean excess doses in tooth enamel obtained after subtraction of the contribution of natural background radiation do not exceed 62 {+-} 28 mGy, 64 {+-} 30 mGy, 49 {+-} 27 mGy and -19 {+-} 36 mGy for all ages of the residents of Makanchi, Urdzhar, Taskesken and the control village of Kokpekty, respectively.

  4. Electron probe X-ray microanalysis of boar and inobuta testes after the Fukushima accident

    International Nuclear Information System (INIS)

    Yamashiro, Hideaki; Abe, Yasuyuki; Hayashi, Gohei; Urushihara, Yusuke; Kuwahara, Yoshikazu; Suzuki, Masatoshi; Kobayashi, Jin; Kino, Yasuyuki; Fukuda, Tomokazu; Tong, Bin; Takino, Sachio; Sugano, Yukou; Sugimura, Satoshi; Yamada, Takahisa; Isogai, Emiko; Fukumoto, Manabu

    2015-01-01

    We aimed to investigate the effect of chronic radiation exposure associated with the Fukushima Daiichi Nuclear Power Plant (FNPP) accident on the testes of boar and inobuta (a hybrid of Sus scrofa and Sus scrofa domestica). This study examined the contamination levels of radioactive caesium (Cs), especially 134 Cs and 137 Cs, in the testis of both boar and inobuta during 2012, after the Fukushima accident. Morphological analysis and electron-probe X-ray microanalysis (EPMA) were also undertaken on the testes. The 134 Cs and 137 Cs levels were 6430 ± 23 and 6820 ± 32 Bq/kg in the boar testes, and 755 ± 13 and 747 ± 17 Bq/kg in the inobuta testes, respectively. The internal and external exposure of total 134 Cs and 137 Cs in the boar testes were 47.1 mGy and 176.2 mGy, respectively, whereas in the inobuta testes, these levels were 6.09 mGy and 59.8 mGy, respectively. Defective spermatogenesis was not detected by the histochemical analysis of radiation-exposed testes for either animal. In neither animal were Cs molecules detected, using EPMA. In conclusion, we showed that adverse radiation-induced effects were not detected in the examined boar and inobuta testes following the chronic radiation exposure associated with the FNPP accident

  5. Chromosomal aberrations of blood lymphocytes induced in vitro by radon-222 daughter α-irradiation

    International Nuclear Information System (INIS)

    Pohl-Rueling, J.; Lettner, H.; Hofmann, W.; Atzmueller, C; Eckl, P.; Haas, O.A.; Obe, G.; Grell-Buechtmann, I.; Van Buul, P.P.W.; Natarajan, A.T.; Schroeder-Kurth, T.; Sasaki, M.S.; Fischer, P.; Kubiak, R.

    2000-01-01

    Blood samples were irradiated in vitro with α-rays emitted from short-lived radon decay products dissolved in the culture medium at doses between 0.03 and 41.4 mGy. The data were collected from experiments conducted during the period 1984-1992 and comprise a total of about 64000 scored metaphases. For statistical reasons, only 60,022 metaphases were used for the subsequent analysis. The results for total chromosome aberrations and dicentrics indicate a linear dose dependence in the dose range above about 10 mGy, consistent with other experimental observations. At doses below about 10 mGy, aberration frequencies cannot be linearly extrapolated from higher doses, suggesting that there is no dependence on dose within a certain low-dose range. In addition, a statistically significant minimum has been observed at a dose of about 0.03 mGy, which is consistently lower than the related control values. The behavior of the aberration frequencies in the low-dose region seems to be influenced by the control values, which also depend on the environmental radiation burdens to the donors before blood sampling and thus were significantly affected by the Chernobyl fallout

  6. Theoretical Studies of Nanoclusters (Briefing Charts)

    Science.gov (United States)

    2015-07-23

    nanoclusters. However, scanning transmission electron microscopy ( STEM ) measures show cluster inversion occurred to produce MgyCux(!) a) copper atoms b...methane (née CLL -1) as a potential explosive ingredient: a theoretical study”, Propellants, Explosives, Pyrotechnics 38, 9-13 (2013). Jesus Paulo L

  7. Towards establishing DRLs for digital mammography in Australia

    International Nuclear Information System (INIS)

    Diffey, J.L; Carteright, L.E.; Collins, L.T.; Grewal, R.K.

    2011-01-01

    Full text: Breastscreen NSW is one of the first breast screening programs to be fully digital. Exposure data is stored in the DICOM image header, making it readily accessible for assessing patient dose. The aim of this work was to determine diagnostic reference levels (DRLs) for the screening program. Approximately 100 examinations, consisting of two views of each breast, were obtained for each system from the central PACS. Third party software was then used to extract the relevant exposure parameters. The mean glandular dose (MGD) was calculated for each image using the methods described by Wu, Boone and Dance. The DRL was calculated from the average mean glandular dose for mediolateral oblique (MLO) views with compressed breast thicknesses of 50-60 mm. For the whole sample, the average MLO compressed breast thickness was 58.84 mm with an average compression force of 109.25 N. The average MGD (Dance) for each examination was 2.93 mGy, compared with 4.6 mGy for film-screen systems. The DRL for CR systems (Dance) was 1.85 mGy, and for DR systems it was 1.13 mGy.

  8. Immobilization of cellulose producing cells (sporotrichum cellulophilum) using irradiated rice husk as a substrate

    International Nuclear Information System (INIS)

    Lina, M.R.; Tamada, M.; Kumakura, M.

    1991-01-01

    An experiment to study the effect of irradiated rice husk as a substrate on cellulase production of free and immobilized cells of S. cellulophium was carried out. Radiation pretreatment of rice husk was done using electron beam accelerator (Dynamitron IEA 3000-25,2), with doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 MGy. The substrate used in cellulase production of free and immobilized cells were cellulose powder as a standard, and 1.0 MGy irradiated rice husk. Concentrations of cellulose powder for free and immobilized cells were 1, 2, 3, 5, and 8% (w/v). Irradiated rice husk concentrations for free cells were 3, 6, 9, 15, and 24% (w/v), whereas for immobilized cells were 3, 6, and 9% (w/v). Results showed that glucose concentration in 1.0 MGy irradiated rice husk was the highest of all irradiated and unirradiated rice husks. The GPA (glucose production activity) values used of free immobilized cells of S. cellulophium in medium containing 1.0 MGy irradiated rice husk were about 50% lower than in cellulose powder medium. Cellulase solution resulted by immobilized cells, either in cellulose powder or in irradiated rice husk media, were clear and did not contain mycelium. (authors). 7 refs, 7 figs

  9. Occupational exposure to staff during endoscopic retrograde cholangiopancreatography in Sudan

    International Nuclear Information System (INIS)

    Sulieman, A.; Elzaki, M.; Khalil, M.

    2011-01-01

    Endoscopic retrograde cholangiopancreatography (ERCP) procedure is an invasive technique that requires fluoroscopic and radiographic exposure. The purpose of this study was to determine the occupational dose of ionising radiation at three gastroenterology departments (Fedial, Soba and Ibn seena hospitals) in Khartoum (Sudan). The radiation dose was measured during 55 therapeutic ERCP procedures. Thermoluminescence dosemeters were used. The mean radiation dose for the first operator was 0.27 mGy for the eye lens, 0.21 for the thyroid, 0.32 for the chest, 0.17 for the hand and 0.22 for the leg. The mean radiation dose for the second operator was 0.21 mGy for the hand and 0.20 mGy for the chest, while the mean radiation dose for the nurse was 0.44 mGy for the hand and 0.19 for the chest. The radiation dose received by the staff in these hospitals was found to be higher than most of the values in the literature. The radiation absorbed dose received by the different organs is relatively low. Additional studies need to be conducted for radiation dose optimisation. (authors)

  10. Level of patient and operator dose in the largest cardiac centre in Greece

    International Nuclear Information System (INIS)

    Tsapaki, V.; Patsilinakos, S.; Voudris, V.; Magginas, A.; Pavlidis, S.; Maounis, T.; Theodorakis, G.; Koutelou, M.; Vrantza, T.; Nearchou, M.; Nikolaki, N.; Kollaros, N.; Kyrozi, E.; Kottou, S.; Karaiskos, P.; Neofotistou, E.; Cokkinos, D.

    2008-01-01

    The objective of this study was to investigate the patient and staff doses in the most frequent interventional cardiology (IC) procedures performed in Onassio, the largest Cardiac Centre in Greece. Data were collected from three digital X-ray systems for 212 coronary angiographies, 203 percutaneous transluminal coronary angio-plasties (PTCA) and 134 various electrophysiological studies. Patient skin dose was measured using suitably calibrated slow radiotherapy films and cardiologist dose using suitably calibrated thermoluminescent dosemeters placed on left arm, hand and foot. Patient median dose area product (DAP) (all examinations) ranged between 6.7 and 83.5 Gy cm 2 . Patient median skin dose in PTCA was 799 mGy (320-1660 mGy) and in RF ablation 160 mGy (35-1920 mGy). Median arm, hand and foot dose to the cardiologist were 12.6, 27 and 13 μSv, respectively, per procedure. The great range of radiation doses received by both patients and operators confirms the need for continuous monitoring of all IC techniques. (authors)

  11. Estimates of Average Glandular Dose with Auto-modes of X-ray Exposures in Digital Breast Tomosynthesis

    Directory of Open Access Journals (Sweden)

    Izdihar Kamal

    2015-05-01

    Full Text Available Objectives: The aim of this research was to examine the average glandular dose (AGD of radiation among different breast compositions of glandular and adipose tissue with auto-modes of exposure factor selection in digital breast tomosynthesis. Methods: This experimental study was carried out in the National Cancer Society, Kuala Lumpur, Malaysia, between February 2012 and February 2013 using a tomosynthesis digital mammography X-ray machine. The entrance surface air kerma and the half-value layer were determined using a 100H thermoluminescent dosimeter on 50% glandular and 50% adipose tissue (50/50 and 20% glandular and 80% adipose tissue (20/80 commercially available breast phantoms (Computerized Imaging Reference Systems, Inc., Norfolk, Virginia, USA with auto-time, auto-filter and auto-kilovolt modes. Results: The lowest AGD for the 20/80 phantom with auto-time was 2.28 milliGray (mGy for two dimension (2D and 2.48 mGy for three dimensional (3D images. The lowest AGD for the 50/50 phantom with auto-time was 0.97 mGy for 2D and 1.0 mGy for 3D. Conclusion: The AGD values for both phantoms were lower against a high kilovolt peak and the use of auto-filter mode was more practical for quick acquisition while limiting the probability of operator error.

  12. Radiation doses to children with shunt-treated hydrocephalus

    Energy Technology Data Exchange (ETDEWEB)

    Holmedal, Lise J. [Helse Fonna, Department of Radiology, Stord Hospital, Stord (Norway); Friberg, Eva G.; Boerretzen, Ingelin; Olerud, Hilde [The Norwegian Radiation Protection Authority, Oesteraas (Norway); Laegreid, Liv [Haukeland University Hospital, Department of Paediatrics, Bergen (Norway); Rosendahl, Karen [University of Bergen, Department of Surgical Sciences, Radiology Section, Bergen (Norway); Great Ormond Street Hospital for Children, Department of Diagnostic Radiology, London (United Kingdom)

    2007-12-15

    Children with shunt-treated hydrocephalus are still followed routinely with frequent head CT scans. To estimate the effective dose, brain and lens doses from these examinations during childhood, and to assess dose variation per examination. All children born between 1983 and 1995 and treated for hydrocephalus between 1983 and 2002 were included. We retrospectively registered the number of examinations and the applied scan parameters. The effective dose was calculated using mean conversion factors from the CT dose index measured free in air, while doses to the lens and brain were estimated using tabulated CT dose index values measured in a head phantom. A total of 687 CT examinations were performed in 67 children. The mean effective dose, lens dose and brain dose to children over 6 months of age were 1.2 mSv, 52 mGy and 33 mGy, respectively, and the corresponding doses to younger children were 3.2 mSv, 60 mGy and 48 mGy. The effective dose per CT examination varied by a factor of 64. None of the children was exposed to doses known to cause deterministic effects. However, since the threshold for radiation-induced damage is not known with certainty, alternative modalities such as US and MRI should be used whenever possible. (orig.)

  13. Skeletal muscle deiodinase type 2 regulation during illness in mice

    NARCIS (Netherlands)

    Kwakkel, J.; van Beeren, H. C.; Ackermans, M. T.; Platvoet-ter Schiphorst, M. C.; Fliers, E.; Wiersinga, W. M.; Boelen, A.

    2009-01-01

    We have previously shown that skeletal muscle deiodinase type 2 (D2) mRNA (listed as Dio2 in MGI Database) is up-regulated in an animal model of acute illness. However, human Studies on the expression Of muscle D2 during illness report conflicting data. Therefore, we evaluated the expression of

  14. Dosimetry of cone beam computed tomography scanning for diagnosis and planning in implant dentistry

    International Nuclear Information System (INIS)

    Santos Pinto de A, E. L.; Manzi, F. R.; Goncalves Z, E.; Nogueira, M. S.; Fernandes Z, M. A.

    2015-10-01

    Full text: The radiation dose and estimate the radiation induced risk of cancer and morpho functional alterations according to BEIR VII (2006) and recommendations of the ICRP 103 (2007) were measured in cone beam computed tomography (CBCT) scanning (Tc Kodak 9000C 3D) in different oral and maxillofacial regions for diagnosis and planning in implant dentistry for each examination protocol: jaw full, maxilla full and jaw and maxilla full associated. Thermoluminescent dosimeters (TLD- 100 H) were placed in an Alderson-Rando in regions corresponding to the crystalline, parotid, submandibular and thyroid glands and ovaries. The highest values for entrance skin dose were observed in the region of the parotid and submandibular glands, 9.612 mGy to 7.912 mGy and 8.818 mGy to 0.483 mGy, respectively. All examination protocols presented on the right and left sides in the region of the submandibular gland the highest values for absorbed dose (D). In the jaw full exam the thyroid glands on both sides presented highest dose values than maxilla full exam. This study allowed measuring the entrance skin dose and the absorbed dose (D) highlighting a dosimetric preponderance to the salivary glands. With danger of to radiation that induces cancer risk was observed that the age group most likely to have to risk of cancer was 20 years, compared to 30, 40, 50, 60,70 and 80 years. (Author)

  15. Low-dose/dose-rate γ radiation depresses neural differentiation and alters protein expression profiles in neuroblastoma SH-SY5Y cells and C17.2 neural stem cells.

    Science.gov (United States)

    Bajinskis, Ainars; Lindegren, Heléne; Johansson, Lotta; Harms-Ringdahl, Mats; Forsby, Anna

    2011-02-01

    The effects of low doses of ionizing radiation on cellular development in the nervous system are presently unclear. The focus of the present study was to examine low-dose γ-radiation-induced effects on the differentiation of neuronal cells and on the development of neural stem cells to glial cells. Human neuroblastoma SH-SY5Y cells were exposed to (137)Cs γ rays at different stages of retinoic acid-induced neuronal differentiation, and neurite formation was determined 6 days after exposure. When SH-SY5Y cells were exposed to low-dose-rate γ rays at the onset of differentiation, the number of neurites formed per cell was significantly less after exposure to either 10, 30 or 100 mGy compared to control cells. Exposure to 10 and 30 mGy attenuated differentiation of immature C17.2 mouse-derived neural stem cells to glial cells, as verified by the diminished expression of glial fibrillary acidic protein. Proteomic analysis of the neuroblastoma cells by 2D-PAGE after 30 mGy irradiation showed that proteins involved in neuronal development were downregulated. Proteins involved in cell cycle and proliferation were altered in both cell lines after exposure to 30 mGy; however, the rate of cell proliferation was not affected in the low-dose range. The radiation-induced attenuation of differentiation and the persistent changes in protein expression is indicative of an epigenetic rather than a cytotoxic mechanism.

  16. Latif et al (18)

    African Journals Online (AJOL)

    DELL

    irradiation source to a test dose of 1.2 mGy and the heating rates of β = 1, 3 and 5 Cs were considered, in order to minimize the effect of ... properties of inorganic materials allows not only ... dose over a wide range and (iii) the ability to store.

  17. Combustion synthesis and preliminary luminescence studies of ...

    Indian Academy of Sciences (India)

    were used such as lithium nitrate (LiNO3), barium nitrate. (BaNO3)2, ammonium .... packed in aluminium foil under 100mGy beta-ray radia- tions. Figure 3 .... 20. Shaat S K K, Swart H C and Ntwaeaborwa O M 2014 J. Alloys. Compd. 587 600.

  18. Ionizing radiations dosimetry: new results in the megagray range

    International Nuclear Information System (INIS)

    Balian, P.

    1989-01-01

    Industrial irradiation for food preservation, medical sterilization and plastic processing is in great expansion and an accurate dosimetry in the megagray range is required. It is also required for safety purposes around nuclear reactors or waste storage sites. The study of photon-matter interaction leads us to consider high-dose dosimeters among the solids in which radiolysis occurs. Organic conductors are indeed good candidates for high-dose dosimetry. These materials show original properties due to the great anisotropy of their electronic system. Radiation effects, especially on the resistivity and on the (E.S.R.) Electron Spin Resonance linewidth, are very important. We show that a simple resistance measurement allows an accurate monitoring of the absorbed dose, in the range 0.01 - 50 MGy, for X-rays, gamma-rays and electron irradiations. The E.S.R. linewidth measurements permits the use of small dosimeters between 1 and 100 MGy. Finally, some organic conductors are proposed as high-temperature dosimeters for irradiation performed up to 120 0 C. The irradiated pure silica contains a large variety of defects. Only the E' center seems helpful for dosimetry purposes, and its electron spin resonance (E.S.R.) signal is simply related to the absorbed dose in the range 0.1 - 3 MGy or even, 0.5 kGy - 5 MGy [fr

  19. Should the automatic exposure control system of CT be disabled when scanning patients with endoaortic stents or mechanical heart valves? A phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Di Leo, Giovanni; Zanardo, Moreno; Secchi, Francesco [IRCCS Policlinico San Donato, Radiology Unit, San Donato Milanese (Italy); Spadavecchia, Chiara [Universita degli Studi di Milano, Dipartimento di Fisica, Milano (Italy); Veronese, Ivan [Universita degli Studi di Milano, Dipartimento di Fisica, Milano (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Milano (Italy); Cantone, Marie Claire [Istituto Nazionale di Fisica Nucleare, Sezione di Milano (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche, Chirurgiche ed Odontoiatriche, Milano (Italy); Sardanelli, Francesco [IRCCS Policlinico San Donato, Radiology Unit, San Donato Milanese (Italy); Universita degli Studi di Milano, Department of Biomedical Science for Health, San Donato Milanese (Italy)

    2017-07-15

    To estimate the impact of endoaortic stents/mechanical heart valves on the output of an automatic exposure control (AEC) system and CT radiation dose. In this phantom study, seven stents and two valves were scanned with varying tube voltage (80/100/120 kVp), AEC activation (enabled/disabled) and prosthesis (present/absent), for a total of 540 scans. For each prosthesis, the dose-length product (DLP) was compared between scans with the AEC enabled and disabled. Percentage confidence levels for differences due to the prosthesis were calculated. Differences between results with the AEC enabled and disabled were not statistically significant (p ≥ 0.059). In the comparison with and without the prosthesis, DLP was unchanged at 80 kVp and 100 kVp, while a slight increase was observed at 120 kVp. The radiation dose varied from 1.8 mGy to 2.4 mGy without the prosthesis and from 1.8 mGy to 2.5 mGy with the prosthesis (confidence level 37-100%). The effect of the prosthesis on the AEC system was negligible and not clinically relevant. Therefore, disabling the AEC system when scanning these patients is not likely to provide a benefit. (orig.)

  20. High pressure gas - a new approach to calorimetry

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    The high particle collision rate and radiation levels in detectors at the new high energy high luminosity proton colliders (SSC, LHC, UNK) put stringent demands on the design of detector components. In particular the forward calorimeters will have to deal with particle fluxes in excess of 4 x 106 per sq cm per s and high radiation doses (at the MGy level)

  1. Radiation dose with digital breast tomosynthesis compared to digital mammography. Per-view analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gennaro, Gisella [Veneto Institute of Oncology IOV- IRCCS, Radiology Unit, Padua (Italy); Bernardi, D. [Azienda Provinciale Servizi Sanitari (APSS), U.O. Senologia Clinica e Screening Mammografico, Department of Diagnostics, Trento (Italy); Houssami, N. [University of Sydney, Screening and Test Evaluation Program (STEP), School of Public Health, Sydney Medical School, Sydney (Australia)

    2018-02-15

    To compare radiation dose delivered by digital mammography (FFDM) and breast tomosynthesis (DBT) for a single view. 4,780 FFDM and 4,798 DBT images from 1,208 women enrolled in a screening trial were used to ground dose comparison. Raw images were processed by an automatic software to determine volumetric breast density (VBD) and were used together with exposure data to compute the mean glandular dose (MGD) according to Dance's model. DBT and FFDM were compared in terms of operation of the automatic exposure control (AEC) and MGD level. Statistically significant differences were found between FFDM and DBT MGDs for all views (CC: MGD{sub FFDM}=1.366 mGy, MGD{sub DBT}=1.858 mGy; p<0.0001; MLO: MGD{sub FFDM}=1.374 mGy, MGD{sub DBT}=1.877 mGy; p<0.0001). Considering the 4,768 paired views, Bland-Altman analysis showed that the average increase of DBT dose compared to FFDM is 38 %, and a range between 0 % and 75 %. Our findings show a modest increase of radiation dose to the breast by tomosynthesis compared to FFDM. Given the emerging role of DBT, its use in conjunction with synthetic 2D images should not be deterred by concerns regarding radiation burden, and should draw on evidence of potential clinical benefit. (orig.)

  2. Assessment of patient dose and radiogenic risks during endoscopic retrograde cholangiopancreatography

    International Nuclear Information System (INIS)

    Sulieman, A.; Elzaki, M.; Alkhorayef, M.; Babikir, E.; Abuzaid, M.; Dalton, A.; Bradley, D.

    2015-10-01

    Endoscopic retrograde cholangiopancreatography (ERCP) is an invasive technique that has been used for over 30 years in the diagnosis and management of pancreaticobiliary disorders. The objectives of this study were to evaluate the patient entrance surface air kerma doses (ESAK) and estimate the organ and effective doses during ERCP in three hospitals in Khartoum. A total of 55 patients were examined in three hospitals in Khartoum state, Sudan. Calibrated thermoluminescence dosimeters (TLD)-Gr-200-A)) were used to measure patients ESAK. The overall mean of ESAK for all ERCP procedures was 42.4 mGy. The mean patient ESAK in Fedail, Soba and Ibn sena centers were 26.7 mGy, 26.0 mGy, 72.4 mGy, respectively. The effective doses in three centers were 1.6, 1.56 and 2.67 mSv in that order and the overall mean effective dose was 2.01 mSv. Patient radiation doses vary widely among the different hospitals. Patient ESAK is low compared to previous studies in the light of the current practice. Patient dose was decreased significantly in the last two decades. (Author)

  3. Occupational radiation exposure in the GDR in 1978

    International Nuclear Information System (INIS)

    Poulheim, K.F.; Rothe, W.; Scheler, R.

    1980-01-01

    In 1978, radiation workers were monitored for external and internal radiation exposure on the basis of film badges (37,980 persons), measurements with a whole-body counter (186 persons) and analyses of biosamples (144 persons). According to the film badge data, the monthly over-exposures (more than 4 mGy) totalled 427. In 13 cases the monthly exposure exceeded 30 mGy, 8 persons received annual doses in the range of 50 to 120 mGy, and the highest annual dose was above 250 mGy. Also, annual collective and annual per caput doses have been given for the exposed population as a whole and some subgroups. Based on model considerations, the internal radiation exposure situation resulting from unintentional intakes of radionuclides has been assessed in terms of committed dose equivalents to members of two selected groups of radiation workers: (a) persons with more-than-average internal contamination levels; (b) persons subjected to frequent individual monitoring. Except for some organ doses, the individual internal radiation exposure was well below one-tenth the maximum permissible dose. (author)

  4. Radiation hormesis using an x-ray radiography device. The fourth report. Radiation hormesis of salad rocket

    International Nuclear Information System (INIS)

    Sakuma, Atsushi; Nakayama, Miho

    2006-01-01

    Radiation hormesis was studied for salad rocket plant (Eruca vesicaria sp.sativa), using different energies of X-ray (100 kV and 10 MV). To get the optimum dose for plant to provide the highest growth, the dose for the seeds was changed from 0 to 3000 mGy using 100 kV of X-ray. The highest growth of the plant was found for the dose of 600 mGy. When the seeds were irradiated to 600 mGy with 100 kV and 10 MV X-rays, in both cases, the growth of the irradiated seeds was higher than those without irradiation, where P-values were 0.0112 and 0.0214, respectively. In the case of 600 mGy irradiation, there was not any significant change in the plant growth between the seeds irradiated with 10 MV and 100 kV X-ray (P=0.862). (author)

  5. Radiation exposure of the gonads in infant brain computerized tomography

    International Nuclear Information System (INIS)

    Berndt, L.; Rosenkranz, G.; Tellkamp, H.

    1988-01-01

    In 61 babies and infants the gonadal dose due to brain computerized tomography was determined over the symphysis by thermoluminescent dosimetry. The average radiation dose was 43 mGy corresponding with data reported. Shielding of the testes in infants is an additional burden and worth discussing because of the low absolute gonadal dose

  6. Chernobyl's Subclinical Legacy: Prenatal Exposure to Radioactive Fallout and School Outcomes in Sweden. NBER Working Paper No. 13347

    Science.gov (United States)

    Almond, Douglas; Edlund, Lena; Palme, Marten

    2007-01-01

    Japanese atomic bomb survivors irradiated 8-25 weeks after ovulation subsequently suffered reduced IQ [Otake and Schull, 1998]. Whether these findings generalize to low doses (less than 10 mGy) has not been established. This paper exploits the natural experiment generated by the Chernobyl nuclear accident in April 1986, which caused a spike in…

  7. Cesium-137 uptake studies on ammonium phospho molybdate irradiated with electrons

    International Nuclear Information System (INIS)

    Rao, K.L.N.; Balasubramanian, K.R.; Shukla, J.P.

    1992-01-01

    Ammonium phospho molybdate is an important inorganic ion exchanger having high selectivity for cesium. This paper discusses the effects of electron irradiation to a dose of 1 mGy on this exchanger with special reference to its ion exchange performance using cesium-137 as a tracer. An explanation is attempted for the slight increase in the distribution coefficients. (author). 5 refs., 1 tab

  8. Analysis of Dose and Dose Distribution for Patients Undergoing Selected X-Ray Diagnostic Procedures in Ghana

    Energy Technology Data Exchange (ETDEWEB)

    Schandorf, C.; Tetteh, G.K

    1998-07-01

    The levels of dose and dose distributions for adult patients undergoing five selected common types of X ray examination in Ghana were determined using thermoluminescence dosemeters (TLD) attached to the skin where the beam enters the patient. To assess the performance of each X ray room surveyed, the mean of the entrance surface dose for patients whose statistics were close to a standard patient (70 kg weight and 20 cm AP trunk thickness) were compared to the Commission of the European Communities guideline values for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP examinations. The third quartiles dose values were 1.3 mGy, 14.5 mGy, 12.0 mGy and 7.9 mGy for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP respectively. Analysis of the data show that 86%, 58%, 37.5% and 50% of radiographic rooms delivered a mean dose greater than the CEC guideline values for chest PA, lumbar spine AP, pelvis/abdomen and skull AP respectively. This suggests that radiographic departments should undertake a review of their radiographic practice in order to bring their doses to optimum levels. (author)

  9. Analysis of Dose and Dose Distribution for Patients Undergoing Selected X-Ray Diagnostic Procedures in Ghana

    International Nuclear Information System (INIS)

    Schandorf, C.; Tetteh, G.K.

    1998-01-01

    The levels of dose and dose distributions for adult patients undergoing five selected common types of X ray examination in Ghana were determined using thermoluminescence dosemeters (TLD) attached to the skin where the beam enters the patient. To assess the performance of each X ray room surveyed, the mean of the entrance surface dose for patients whose statistics were close to a standard patient (70 kg weight and 20 cm AP trunk thickness) were compared to the Commission of the European Communities guideline values for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP examinations. The third quartiles dose values were 1.3 mGy, 14.5 mGy, 12.0 mGy and 7.9 mGy for chest PA, lumbar spine AP, pelvis/abdomen AP and skull AP respectively. Analysis of the data show that 86%, 58%, 37.5% and 50% of radiographic rooms delivered a mean dose greater than the CEC guideline values for chest PA, lumbar spine AP, pelvis/abdomen and skull AP respectively. This suggests that radiographic departments should undertake a review of their radiographic practice in order to bring their doses to optimum levels. (author)

  10. Establishment of diagnostic reference levels for dental panoramic radiography in Greece

    International Nuclear Information System (INIS)

    Manousaridis, G.; Koukorava, C.; Hourdakis, C.J.; Kamenopoulou, V.; Yakoumakis, E.; Tsiklakis, K.

    2015-01-01

    The purpose of the present study was to present the national diagnostic reference levels (DRL) established for panoramic dental examinations in Greece. The establishment of DRL, as a tool for the optimisation of radiological procedures, is a requirement of national regulations. Measurements performed by the Greek Atomic Energy Commission on 90 panoramic systems have been used for the derivation of DRL values. DRL values have been proposed for exposure settings of different patient types (child, small adult and standard adult), both for film and digital imaging. The DRLs for different patient types are grouped in three categories: children, small adults (corresponding to female) and average adults (corresponding to male). Proposed DRLs for these groups are 2.2, 3.3 and 4.1 mGy, respectively. In order to investigate the correlation of DRLs with the available imaging modalities (CR, DR and film), this parameter was taken into account. DR imaging DRL is the lowest at 3.5 mGy, CR imaging the highest at 4.2 mGy and film imaging at 3.7 mGy. In order to facilitate comparison with other studies, kerma-width product values were calculated from K i , air and field size. (authors)

  11. The rate of X-ray-induced DNA double-strand break repair in the embryonic mouse brain is unaffected by exposure to 50 Hz magnetic fields.

    Science.gov (United States)

    Woodbine, Lisa; Haines, Jackie; Coster, Margaret; Barazzuol, Lara; Ainsbury, Elizabeth; Sienkiewicz, Zenon; Jeggo, Penny

    2015-06-01

    Following in utero exposure to low dose radiation (10-200 mGy), we recently observed a linear induction of DNA double-strand breaks (DSB) and activation of apoptosis in the embryonic neuronal stem/progenitor cell compartment. No significant induction of DSB or apoptosis was observed following exposure to magnetic fields (MF). In the present study, we exploited this in vivo system to examine whether exposure to MF before and after exposure to 100 mGy X-rays impacts upon DSB repair rates. 53BP1 foci were quantified following combined exposure to radiation and MF in the embryonic neuronal stem/progenitor cell compartment. Embryos were exposed in utero to 50 Hz MF at 300 μT for 3 h before and up to 9 h after exposure to 100 mGy X-rays. Controls included embryos exposed to MF or X-rays alone plus sham exposures. Exposure to MF before and after 100 mGy X-rays did not impact upon the rate of DSB repair in the embryonic neuronal stem cell compartment compared to repair rates following radiation exposure alone. We conclude that in this sensitive system MF do not exert any significant level of DNA damage and do not impede the repair of X-ray induced damage.

  12. Level and distribution of the radiation dose to the population from a mammography screening programme in New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Bulling, S.M.; Nicoll, J.J. [Otago Univ., Dunedin (New Zealand). Dept. of Physics

    1995-12-31

    The Otago Southland Breast Screening Programme offers biennial mammography to 19,000 eligible women on the South Island of New Zealand. A Quality Assurance programme ensures that international performance standards are met, in particular the radiation dose for a mammogram of 5 cm CIRS-X phantom is 1.7 mGy and careful retake analysis undertaken. This however does not reveal the absorbed dose received by individuals, nor how this varies between individuals. Machine parameters and compressed breast thickness for each film were recorded for 310 women who attended one centre during the three months ending February 1993 and absorbed doses calculated using Monte Carlo data. The mean compressed breast thickness for the 310 women was 4.9 cm, doses received for individual films ranged from 0.7 to 8.5 mGy while patient total doses were in the range 4 to 29 mGy with 75% of women receiving a dose of 7.1 mGy or less. (Author).

  13. Should the automatic exposure control system of CT be disabled when scanning patients with endoaortic stents or mechanical heart valves? A phantom study

    International Nuclear Information System (INIS)

    Di Leo, Giovanni; Zanardo, Moreno; Secchi, Francesco; Spadavecchia, Chiara; Veronese, Ivan; Cantone, Marie Claire; Sardanelli, Francesco

    2017-01-01

    To estimate the impact of endoaortic stents/mechanical heart valves on the output of an automatic exposure control (AEC) system and CT radiation dose. In this phantom study, seven stents and two valves were scanned with varying tube voltage (80/100/120 kVp), AEC activation (enabled/disabled) and prosthesis (present/absent), for a total of 540 scans. For each prosthesis, the dose-length product (DLP) was compared between scans with the AEC enabled and disabled. Percentage confidence levels for differences due to the prosthesis were calculated. Differences between results with the AEC enabled and disabled were not statistically significant (p ≥ 0.059). In the comparison with and without the prosthesis, DLP was unchanged at 80 kVp and 100 kVp, while a slight increase was observed at 120 kVp. The radiation dose varied from 1.8 mGy to 2.4 mGy without the prosthesis and from 1.8 mGy to 2.5 mGy with the prosthesis (confidence level 37-100%). The effect of the prosthesis on the AEC system was negligible and not clinically relevant. Therefore, disabling the AEC system when scanning these patients is not likely to provide a benefit. (orig.)

  14. Radiation doses from mammography in Australia

    International Nuclear Information System (INIS)

    Thomson, J.E.M.; Young, B.F.; Young, J.G.; Tingey, D.R.C.

    1991-05-01

    During 1989-90 the Australian Radiation Laboratory conducted a postal survey of at least 90% of the mammographic facilities in Australia. The primary aim of the survey was to measure the mean glandular dose (MGD) and the X-ray beam half value layer (HVL) for a typical mammograph. The MGD and HVL were measured with a specially designed tissue equivalent monitor. In all, 258 mammographic centres were surveyed. It was found that for centres using film-screen imaging, the average mean glandular dose was 1.83 mGy for centres using grids and 0.84 mGy for centres not using grids. In addition to the MGD and HVL, comprehensive statistical information was collected and data is presented on the types of equipment and techniques used, the number and age of patients and demographic distribution of centres. Results indicate that the use of a grid is the major factor determining dose and several other factors appear to have minor effects. In view of the distribution of MGD, it is recommended that the mean glandular dose per image, for a 5 cm compressed breast thickness, should not exceed 2.0 mGy when a grid is used and 1.0 mGy without a grid. 63 refs., 11 tabs., 15 figs

  15. Mutational influences of low-dose and high let ionizing radiation in drosophila melanogaster

    Science.gov (United States)

    Lei, Huang; Fanjun, Kong; Sun, Yeqing

    For cosmic environment consists of a varying kinds of radiation particles including high Z and energy ions which was charactered with low-dose and high RBE, it is important to determine the possible biofuctions of high LET radiation on human beings. To analyse the possible effectes of mutational influences of low-dose and high-LET ionizing radiation, wild fruit flies drosophila melanogaster were irradiated by 12C6+ ions in two LET levels (63.3 and 30 keV/µum) with different low doses from 2mGy to 2000mGy (2, 20, 200, 2000mGy) in HIRFL (Heavy ion radiation facility laboratory, lanzhou, China).In the same LET value group, the average polymorphic frequency was elevated along with adding doses of irradation, the frequency in 2000 mGy dose samples was significantly higher than other samples (p<0.01).These results suggest that genomic DNA sequence could be effected by low-dose and high-LET ionizing radiation, the irradiation dose is an important element in genomic mutation frequency origination.

  16. Study of an optimization protocol for radiographic techniques in computerized radiology

    International Nuclear Information System (INIS)

    Abrantes, Marcos Eugenio Silva

    2015-01-01

    This work is designed to produce information for the improvement of image quality to deployment in a radiology department based on previous reviews of the images by questionnaires of acceptance and quality e recognition of the parameters used in chest radiographic techniques. The data collected were divided by male, female, PA and LAT thickness, body mass index, biotypes, anthropomorphic parameters and body evaluation associated with constant voltage and the additional filtration. The results show the predominance of 35 and 40 constants with additional filtration from 0.5 to 1.5 mmAl, voltage in male: (PA and LAT) 86-92 kV and 96-112 kV, female: 85-98 kV and 96-112 kV. The charge applied to the tube for males: (PA and LAT) 5-10 mA.s and 5-16 mA.s, female: (PA and LAT) 6.3-8 mA.s and 9-14 mA.s. Absorbed doses for males: (PA and PF) 0.04-0.17 mGy and 0.03-0.19 mGy and from female (PA and PF) from 0.03-0.22 mGy and 0, 04-0.17 mGy. This procedure can be used in radiology department to implement and acceptance in the quality of images. (author)

  17. Crystal growth and thermoluminescence response of NaZr2(PO4)3 at high gamma radiation doses

    International Nuclear Information System (INIS)

    Ordóñez-Regil, E.; Contreras-Ramírez, A.; Fernández-Valverde, S.M.; González-Martínez, P.R.; Carrasco-Ábrego, H.

    2013-01-01

    Graphical abstract: -- Highlights: •NaZr 2 (PO 4 ) 3 exposed to gamma doses of 10, 30 and 50 MGy. •Gamma radiation produced growth of the crystal size of the NZP. •Morphology changes were reversible by heating. •Linear relationship between the thermoluminescence and the applied gamma dose. •This property could be useful for high-level gamma dosimetry. -- Abstract: This work describes the synthesis and characterization of NaZr 2 (PO 4 ) 3 . The stability of this material under high doses of gamma radiation was investigated in the range of 10–50 MGy. Samples of unaltered and gamma irradiated NaZr 2 (PO 4 ) 3 were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermoluminescence. The results showed that while functional groups were not affected by the gamma irradiation, morphology changes were observed with increasing doses of gamma irradiation. The morphology of the non-irradiated compound is agglomerated flakes; however, irradiation at 10 MGy splits the flakes inducing the formation of well-defined cubes. Gamma irradiation induced the crystal size of the NaZr 2 (PO 4 ) 3 to grow. The heat treatment (973 K) of samples irradiated at 50 MGy resulted in the recovery of the original morphology. Furthermore, the thermoluminescence analysis of the irradiated compound is reported

  18. Dosimetry of cone beam computed tomography scanning for diagnosis and planning in implant dentistry

    Energy Technology Data Exchange (ETDEWEB)

    Santos Pinto de A, E. L.; Manzi, F. R.; Goncalves Z, E. [Pontifical Catholic University of Minas Gerais, Av. Jose Gaspar 500, 30535-901 Belo Horizonte, Minas Gerais (Brazil); Nogueira, M. S.; Fernandes Z, M. A., E-mail: madelon@cdtn.br [Development Center of Nuclear Technology / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901Belo Horizonte, Minas Gerais (Brazil)

    2015-10-15

    Full text: The radiation dose and estimate the radiation induced risk of cancer and morpho functional alterations according to BEIR VII (2006) and recommendations of the ICRP 103 (2007) were measured in cone beam computed tomography (CBCT) scanning (Tc Kodak 9000C 3D) in different oral and maxillofacial regions for diagnosis and planning in implant dentistry for each examination protocol: jaw full, maxilla full and jaw and maxilla full associated. Thermoluminescent dosimeters (TLD- 100 H) were placed in an Alderson-Rando in regions corresponding to the crystalline, parotid, submandibular and thyroid glands and ovaries. The highest values for entrance skin dose were observed in the region of the parotid and submandibular glands, 9.612 mGy to 7.912 mGy and 8.818 mGy to 0.483 mGy, respectively. All examination protocols presented on the right and left sides in the region of the submandibular gland the highest values for absorbed dose (D). In the jaw full exam the thyroid glands on both sides presented highest dose values than maxilla full exam. This study allowed measuring the entrance skin dose and the absorbed dose (D) highlighting a dosimetric preponderance to the salivary glands. With danger of to radiation that induces cancer risk was observed that the age group most likely to have to risk of cancer was 20 years, compared to 30, 40, 50, 60,70 and 80 years. (Author)

  19. Dosimetry using Gafchromic XR-RV2 radiochromic films in interventional radiology

    International Nuclear Information System (INIS)

    Neocleous, A.; Yakoumakis, E.; Gialousis, G.; Dimitriadis, A.; Yakoumakis, N.; Georgiou, E.

    2011-01-01

    Patient dose measurements of local entrance dose to the skin have been carried out using radiochromic film (Gafchromic XR-RV2) in a sample of interventional procedures. The major aim of the work was to measure patient entrance dose from such examinations using Gafchromic XR-RV2. Forty-five various interventional procedures (including nephrostomies and urinary stenting, biliary stenting and percutaneous transhepatic biliary drainage (PTBD) and aorta stent grafting) were evaluated. Maximum entrance doses were 537±119 mGy in nephrostomies, 943±631 mGy in biliary stenting and PTBD and 2425±569 mGy in aorta stent grafting. Results indicate that all patients undergoing aorta stent grafting received skin dose above 1500 mGy, which means that there is an increasing potential to suffer radiation-induced skin injuries. The film provides dose mapping, the position of the skin area with highest dose and can be used for immediate qualitative and as well as for quantitative assessment of patient skin dose. (authors)

  20. SU-E-I-15: Comparison of Radiation Dose for Radiography and EOS in Adolescent Scoliosis Patients

    Energy Technology Data Exchange (ETDEWEB)

    Schueler, B; Walz-Flannigan, A [Mayo Clinic, Rochester, MN (United States)

    2014-06-01

    Purpose: To estimate patient radiation dose for whole spine imaging using EOS, a new biplanar slot-scanning radiographic system and compare with standard scoliosis radiography. Methods: The EOS imaging system (EOS Imaging, Paris, France) consists of two orthogonal x-ray fan beams which simultaneously acquire frontal and lateral projection images of a standing patient. The patient entrance skin air kerma was measured for each projection image using manufacturer-recommended exposure parameters for spine imaging. Organ and effective doses were estimated using a commercially-available Monte Carlo simulation program (PCXMC, STUK, Radiation and Nuclear Safety Authority, Helsinki, Finland) for a 15 year old mathematical phantom model. These results were compared to organ and effective dose estimated for scoliosis radiography using computed radiography (CR) with standard exposure parameters obtained from a survey of pediatric radiographic projections. Results: The entrance skin air kerma for EOS was found to be 0.18 mGy and 0.33 mGy for posterior-anterior (PA) and lateral projections, respectively. This compares to 0.76 mGy and 1.4 mGy for CR, PA and lateral projections. Effective dose for EOS (PA and lateral projections combined) is 0.19 mSv compared to 0.51 mSv for CR. Conclusion: The EOS slot-scanning radiographic system allows for reduced patient radiation dose in scoliosis patients as compared to standard CR radiography.

  1. Reducing the radiation dose to the eye lens region during CT brain examination: the potential beneficial effect of the combined use of bolus and a bismuth shield

    International Nuclear Information System (INIS)

    Lai, C.W.K.; Chan, T.P.; Cheung, H.Y.; Wong, T.H.

    2015-01-01

    Objective: Computed Tomography (CT) is the leading contributor to medical exposure to ionizing radiation. Although the use of CT brain scans for patients with head injuries and convulsions has shown a tremendous growth, it has raised substantial concerns in the general public because of the risk of radiation-induced cataracts: the current available strategies to reduce the radiation dose to the eye lens region are limited. Therefore, the present research project was initiated with the aim of evaluating the potential benefit of the combined use of bolus and a bismuth shield on reducing the radiation dose to the eye lens region during CT brain examination. Materials and methods: We conducted a series of phantom studies to measure the entrance surface dose (ESD) that is delivered to the eye lens region during CT brain examination under the effect of different scanning and shielding setups. Results: Our results indicated, during CT brain examination: (1) a drastic reduction of 92.5% in the ESD to the eye lens region was found when the CT gantry was tilted from 0 deg. (overall ESD = 30.7 mGy) to 30 deg. cranially (overall ESD = 2.4 mGy), and (2) when the CT gantry was positioned at 0 deg. (the common practice in the clinical setting), the setups with the application of a) a bismuth shield, b) a bismuth shield with a face shield (air gap), c) a bismuth shield with bolus, and d) a bismuth shield with bolus and an air gap can result in an acceptable level of image quality with a smaller overall ESD delivered to the eye lens region (overall ESD = 23.2 mGy, 24 mGy, 21 mGy and 19.9 mGy, respectively) than the setup without the bismuth shield applied (overall ESD = 30.7 mGy). Conclusion: When the primary beam scanning through the eye lens region is unavoidable during CT brain examination, the combined use of a bismuth shield with bolus and a face shield is an easy-to-use and inexpensive shielding setup to reduce the radiation dose delivered to the eye lens region while

  2. The long-term effects of acute exposure to ionising radiation on survival and fertility in Daphnia magna

    Energy Technology Data Exchange (ETDEWEB)

    Sarapultseva, Elena I. [Department of Biology, Institute of Nuclear Power Engineering NRNU MEPhI, Studgorodok,1, Obninsk, Kaluga Region 249040 (Russian Federation); National Research Nuclear University “MEPhI”, Kashirskoe Highway, 31, Moscow 115409 (Russian Federation); Dubrova, Yuri E., E-mail: yed2@le.ac.uk [Department of Genetics, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkina Str. 3, 11933 Moscow (Russian Federation)

    2016-10-15

    The results of recent studies have provided strong evidence for the transgenerational effects of parental exposure to ionising radiation and chemical mutagens. However, the transgenerational effects of parental exposure on survival and fertility remain poorly understood. To establish whether parental irradiation can affect the survival and fertility of directly exposed organisms and their offspring, crustacean Daphnia magna were given 10, 100, 1000 and 10,000 mGy of acute γ-rays. Exposure to 1000 and 10,000 mGy significantly compromised the viability of irradiated Daphnia and their first-generation progeny, but did not affect the second-generation progeny. The fertility of F{sub 0} and F{sub 1}Daphnia gradually declined with the dose of parental exposure and significantly decreased at dose of 100 mGy and at higher doses. The effects of parental irradiation on the number of broods were only observed among the F{sub 0}Daphnia exposed to 1000 and 10,000 mGy, whereas the brood size was equally affected in the two consecutive generations. In contrast, the F{sub 2} total fertility was compromised only among progeny of parents that received the highest dose of 10,000 mGy. We propose that the decreased fertility observed among the F{sub 2} progeny of parents exposed to 10,000 mGy is attributed to transgenerational effects of parental irradiation. Our results also indicate a substantial recovery of the F{sub 2} progeny of irradiated F{sub 0}Daphnia exposed to the lower doses of acute γ-rays. - Highlights: • Viability of irradiated daphnids and their F{sub 1} progeny is compromised. • Viability of the F{sub 2} progeny of irradiated parents is not affected. • Total fertility of irradiated daphnids and their F{sub 1} progeny declines with the dose. • Total fertility of the F{sub 2} progeny of parents exposed to 10,000 mGy is compromised. • The decreased fertility among the F{sub 2} progeny is transgenerational phenomenon.

  3. Quantifying murine bone marrow and blood radiation dose response following {sup 18}F-FDG PET with DNA damage biomarkers

    Energy Technology Data Exchange (ETDEWEB)

    Manning, Grainne [Biological Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 ORQ (United Kingdom); Taylor, Kristina [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON (Canada); Finnon, Paul [Biological Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 ORQ (United Kingdom); Lemon, Jennifer A.; Boreham, Douglas R. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, ON (Canada); Badie, Christophe, E-mail: christophe.badie@phe.gov.uk [Biological Effects Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxfordshire OX11 ORQ (United Kingdom)

    2014-12-15

    Highlights: • Mice received either a range of {sup 18}F-FDG activities or whole body X-ray doses. • Blood samples were collected at 24 and 43 h for MN-RET and QPCR analysis. • Regression analysis showed that both types of exposure produced a linear response. • BM doses of 33 mGy ({sup 18}F-FDG) and 25 mGy X-rays were significantly higher than controls. • No significant difference between internal ({sup 18}F-FDG) and external (X-ray) was found. - Abstract: The purpose of this study was to quantify the poorly understood radiation doses to murine bone marrow and blood from whole-body fluorine 18 ({sup 18}F)-fluorodeoxyglucose (FDG) positron emission tomography (PET), by using specific biomarkers and comparing with whole body external low dose exposures. Groups of 3–5 mice were randomly assigned to 10 groups, each receiving either a different activity of {sup 18}F-FDG: 0–37 MBq or whole body irradiated with corresponding doses of 0–300 mGy X-rays. Blood samples were collected at 24 h and at 43 h for reticulocyte micronucleus assays and QPCR analysis of gene expression in peripheral blood leukocytes. Blood and bone marrow dose estimates were calculated from injected activities of {sup 18}F-FDG and were based on a recommended ICRP model. Doses to the bone marrow corresponding to 33.43 mGy and above for internal {sup 18}F-FDG exposure and to 25 mGy and above for external X-ray exposure, showed significant increases in radiation-induced MN-RET formation relative to controls (P < 0.05). Regression analysis showed that both types of exposure produced a linear response with linear regression analysis giving R{sup 2} of 0.992 and 0.999 for respectively internal and external exposure. No significant difference between the two data sets was found with a P-value of 0.493. In vivo gene expression dose–responses at 24 h for Bbc3 and Cdkn1 were similar for {sup 18}F-FDG and X-ray exposures, with significant modifications occurring for doses over 300 mGy for Bbc3

  4. Fetal shielding combined with state of the art CT dose reduction strategies during maternal chest CT

    Energy Technology Data Exchange (ETDEWEB)

    Chatterson, Leslie C., E-mail: lch088@mail.usask.ca [Department of Diagnostic Imaging, University of Saskatchewan (Canada); Leswick, David A.; Fladeland, Derek A. [Department of Diagnostic Imaging, University of Saskatchewan (Canada); Hunt, Megan M.; Webster, Stephen [Saskatchewan Ministry of Labour Relations and Workplace Safety (Canada); Lim, Hyun [Department of Community Health and Epidemiology, College of Medicine, University of Saskatchewan (Canada)

    2014-07-15

    Purpose: Custom bismuth-antimony shields were previously shown to reduce fetal dose by 53% on an 8DR (detector row) CT scanner without dynamic adaptive section collimation (DASC), automatic tube current modulation (ATCM) or adaptive statistical iterative reconstruction (ASiR). The purpose of this study is to compare the effective maternal and average fetal organ dose reduction both with and without bismuth-antimony shields on a 64DR CT scanner using DASC, ATCM and ASiR during maternal CTPA. Materials and methods: A phantom with gravid prosthesis and a bismuth-antimony shield were used. Thermoluminescent dosimeters (TLDs) measured fetal radiation dose. The average fetal organ dose and effective maternal dose were determined using 100 kVp, scanning from the lung apices to the diaphragm utilizing DASC, ATCM and ASiR on a 64DR CT scanner with and without shielding in the first and third trimester. Isolated assessment of DASC was done via comparing a new 8DR scan without DASC to a similar scan on the 64DR with DASC. Results: Average third trimester unshielded fetal dose was reduced from 0.22 mGy ± 0.02 on the 8DR to 0.13 mGy ± 0.03 with the conservative 64DR protocol that included 30% ASiR, DASC and ATCM (42% reduction, P < 0.01). Use of a shield further reduced average third trimester fetal dose to 0.04 mGy ± 0.01 (69% reduction, P < 0.01). The average fetal organ dose reduction attributable to DASC alone was modest (6% reduction from 0.17 mGy ± 0.02 to 0.16 mGy ± 0.02, P = 0.014). First trimester fetal organ dose on the 8DR protocol was 0.07 mGy ± 0.03. This was reduced to 0.05 mGy ± 0.03 on the 64DR protocol without shielding (30% reduction, P = 0.009). Shields further reduced this dose to below accurately detectable levels. Effective maternal dose was reduced from 4.0 mSv on the 8DR to 2.5 mSv on the 64DR scanner using the conservative protocol (38% dose reduction). Conclusion: ASiR, ATCM and DASC combined significantly reduce effective maternal and fetal

  5. Fetal shielding combined with state of the art CT dose reduction strategies during maternal chest CT

    International Nuclear Information System (INIS)

    Chatterson, Leslie C.; Leswick, David A.; Fladeland, Derek A.; Hunt, Megan M.; Webster, Stephen; Lim, Hyun

    2014-01-01

    Purpose: Custom bismuth-antimony shields were previously shown to reduce fetal dose by 53% on an 8DR (detector row) CT scanner without dynamic adaptive section collimation (DASC), automatic tube current modulation (ATCM) or adaptive statistical iterative reconstruction (ASiR). The purpose of this study is to compare the effective maternal and average fetal organ dose reduction both with and without bismuth-antimony shields on a 64DR CT scanner using DASC, ATCM and ASiR during maternal CTPA. Materials and methods: A phantom with gravid prosthesis and a bismuth-antimony shield were used. Thermoluminescent dosimeters (TLDs) measured fetal radiation dose. The average fetal organ dose and effective maternal dose were determined using 100 kVp, scanning from the lung apices to the diaphragm utilizing DASC, ATCM and ASiR on a 64DR CT scanner with and without shielding in the first and third trimester. Isolated assessment of DASC was done via comparing a new 8DR scan without DASC to a similar scan on the 64DR with DASC. Results: Average third trimester unshielded fetal dose was reduced from 0.22 mGy ± 0.02 on the 8DR to 0.13 mGy ± 0.03 with the conservative 64DR protocol that included 30% ASiR, DASC and ATCM (42% reduction, P < 0.01). Use of a shield further reduced average third trimester fetal dose to 0.04 mGy ± 0.01 (69% reduction, P < 0.01). The average fetal organ dose reduction attributable to DASC alone was modest (6% reduction from 0.17 mGy ± 0.02 to 0.16 mGy ± 0.02, P = 0.014). First trimester fetal organ dose on the 8DR protocol was 0.07 mGy ± 0.03. This was reduced to 0.05 mGy ± 0.03 on the 64DR protocol without shielding (30% reduction, P = 0.009). Shields further reduced this dose to below accurately detectable levels. Effective maternal dose was reduced from 4.0 mSv on the 8DR to 2.5 mSv on the 64DR scanner using the conservative protocol (38% dose reduction). Conclusion: ASiR, ATCM and DASC combined significantly reduce effective maternal and fetal

  6. Investigation of lung nodule detectability in low-dose 320-slice computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, J. D.; Paul, N. S.; Siewerdsen, J. H. [Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Department of Medical Imaging, Toronto General Hospital, Toronto, Ontario M5G 2C6 (Canada); Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario M5G 2M9 (Canada) and Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

    2009-05-15

    Low-dose imaging protocols in chest CT are important in the screening and surveillance of suspicious and indeterminate lung nodules. Techniques that maintain nodule detectability yet permit dose reduction, particularly for large body habitus, were investigated. The objective of this study was to determine the extent to which radiation dose can be minimized while maintaining diagnostic performance through knowledgeable selection of reconstruction techniques. A 320-slice volumetric CT scanner (Aquilion ONE, Toshiba Medical Systems) was used to scan an anthropomorphic phantom at doses ranging from {approx}0.1 mGy up to that typical of low-dose CT (LDCT, {approx}5 mGy) and diagnostic CT ({approx}10 mGy). Radiation dose was measured via Farmer chamber and MOSFET dosimetry. The phantom presented simulated nodules of varying size and contrast within a heterogeneous background, and chest thickness was varied through addition of tissue-equivalent bolus about the chest. Detectability of a small solid lung nodule (3.2 mm diameter, -37 HU, typically the smallest nodule of clinical significance in screening and surveillance) was evaluated as a function of dose, patient size, reconstruction filter, and slice thickness by means of nine-alternative forced-choice (9AFC) observer tests to quantify nodule detectability. For a given reconstruction filter, nodule detectability decreased sharply below a threshold dose level due to increased image noise, especially for large body size. However, nodule detectability could be maintained at lower doses through knowledgeable selection of (smoother) reconstruction filters. For large body habitus, optimal filter selection reduced the dose required for nodule detection by up to a factor of {approx}3 (from {approx}3.3 mGy for sharp filters to {approx}1.0 mGy for the optimal filter). The results indicate that radiation dose can be reduced below the current low-dose (5 mGy) and ultralow-dose (1 mGy) levels with knowledgeable selection of

  7. Penelitian Nilai Beban Pencemaran Pada Beberapa Ekstrak Zat Warna Alam

    Directory of Open Access Journals (Sweden)

    Kun Lestari

    2016-04-01

    Full Text Available Zat Pewarna Alam (ZWA akan direkomendasikan sebagai pewarna yang ramah baik bagi lingkungan maupun kesehatan, disebabkan karena kandungan komponen alaminya mempunyai nilai beban pencemaran yang rendah, mudah terdegradasi secara biologis dan tidak beracun. Pernyataan tersebut perlu diyakinkan kebenarannya. Telah dilakukan pengujian terhadap ekstrak pekat (0,75-1,00° Be dari 13 jenis sumber ZWA dari beberapa daerah di Indonesia yaitu: bakau, secang. sonokeling. bayam, markisa. bengkirai, nangka, pinus, kruing, kara benguk, tingi, tegeran dan mengkudu. Bahan pencemaran dinyatakan terhadap nilai BOD5, COD dan kandungan Fe (besi dalam ekstrak pekat yang telah tersimpan selama ±12 bulan. Dari hasil pengujian terlihat bahwa kadar BOD5 dan COD dari 13 jenis ekstrak ZWA mempunyai nilai 1700 mg/l. Tujuh jenis ekstrak ZWA yaitu ekstrak dari kayu nangka, kayu pinus. kayu kruing, kulit kara benguk, kulit kayu tingi, kayu tegeran dan akar mengkudu mempunyai nilai BOD5 dan COD 1000 mg/l, sedangkan ekstrak kulit batang bakau, kayu secang, kayu sonokeling, kayu buyam, kulit buah markisa dan kayu bengkirai mempunyai nilai BOD5 dan COD antara 1100 - 1700 mg/I. Dibandingkan dengan beban pencemaran yang diakibatkan oleh limbah cair pada pencelupan batik menggunakan zat warna sintetis (ZWS seperti Indigosol yang mempunyai nilai BOD5 = 3.053 mg/I, COD = 10.230 mg/I, dan Naphtol yang mempunyai nilai BOD5 = 5.411 mg/I, COD= 19.921 mg/I maka beban pencemaran ekstrak pekat ZWA masih jauh lebih kecil. Melihat perbandingan COD/BOD5 (=1,3-1,6, beban pencemaran ekstrak pekat ZWA dapat dikelompokkan ke dalam golongan air limbah rumah tangga (COD/BOD5 (2.Zat Pewarna Alam (ZWA akan direkomendasikan sebagai pewarna yang ramah baik bagi lingkungan maupun kesehatan, disebabkan karena kandungan komponen alaminya mempunyai nilai beban pencemaran yang rendah, mudah terdegradasi secara biologis dan tidak beracun. Pernyataan tersebut perlu diyakinkan kebenarannya. Telah dilakukan

  8. Evaluation of the peripheral dose in stereotactic radiotherapy and radiosurgery treatments

    Energy Technology Data Exchange (ETDEWEB)

    Di Betta, Erika; Fariselli, Laura; Bergantin, Achille; Locatelli, Federica; Del Vecchio, Antonella; Broggi, Sara; Fumagalli, Maria Luisa [Department of Neurosurgery, Division of Medical Physics, Fondazione IRCCS, Istituto Neurologico C. Besta, 20133 Milano (Italy); Department of Neurosurgery, Division of Radiotherapy, Fondazione IRCCS, Istituto Neurologico C. Besta, 20133 Milano (Italy); CyberKnife Centre, Centro Diagnostico Italiano, 20147 Milano (Italy); Division of Medical Physics, Fondazione IRCCS, Istituto S. Raffaele, 20132 Milano (Italy); Department of Neurosurgery, Division of Medical Physics, Fondazione IRCCS, Istituto Neurologico C. Besta, 20133 Milano (Italy)

    2010-07-15

    Purpose: The main purpose of this work was to compare peripheral doses absorbed during stereotactic treatment of a brain lesion delivered using different devices. These data were used to estimate the risk of stochastic effects. Methods: Treatment plans were created for an anthropomorphic phantom and delivered using a LINAC with stereotactic cones and a multileaf collimator, a CyberKnife system (before and after a supplemental shielding was applied), a TomoTherapy system, and a Gamma Knife unit. For each treatment, 5 Gy were prescribed to the target. Measurements were performed with thermoluminescent dosimeters inserted roughly in the position of the thyroid, sternum, upper lung, lower lung, and gonads. Results: Mean doses ranged from of 4.1 (Gamma Knife) to 62.8 mGy (LINAC with cones) in the thyroid, from 2.3 (TomoTherapy) to 30 mGy (preshielding CyberKnife) in the sternum, from 1.7 (TomoTherapy) to 20 mGy (preshielding CyberKnife) in the upper part of the lungs, from 0.98 (Gamma Knife) to 15 mGy (preshielding CyberKnife) in the lower part of the lungs, and between 0.3 (Gamma Knife) and 10 mGy (preshielding CyberKnife) in the gonads. Conclusions: The peripheral dose absorbed in the sites of interest with a 5 Gy fraction is low. Although the risk of adverse side effects calculated for 20 Gy delivered in 5 Gy fractions is negligible, in the interest of optimum patient radioprotection, further studies are needed to determine the weight of each contributor to the peripheral dose.

  9. Some experiences from radiation protection of patients undergoing X-ray examinations in Tanzania

    International Nuclear Information System (INIS)

    Ngaile, J.E.; Muhogora, W.E.; Nyanda, A.M.

    2001-01-01

    A study of patient entrance surface dose (ESD) received by adult patients was undertaken in five major diagnostic facilities in Tanzania. Five selected X-ray projections for chest PA; abdomen AP; lumbar spine AP; lumbar spine LAT and pelvis AP were done in the study. The mean ESDs after introduction of dose reduction methods were 0.34 mGy, 5.41 mGy, 3.7 mGy, 4.8 mGy and 8.8 mGy for chest PA; abdomen AP; pelvis AP; lumbar spine AP and lumbar spine LAT, respectively. The variations of doses observed in the study were influenced by performance characteristic of X-ray equipment, patient shape and size, type of image receptor, radiographic techniques as well as skills employed. The results show that increasing the tube voltage reduced the ESD by 35.5%, while lowering of mAs reduced ESD in the range from 15% to 60%. The reduction of ESD by increasing the filtration ranged from 11% to 58% while increasing of speed class of film-screen combination reduced the ESD in the range from 33% to 57%. The corresponding results of image quality show that out of 1064 scores of image criteria 298,481 and 285 were rated for good, satisfactory and poor respectively. The results of this study provide an evidence of existing potential for dose reduction in the diagnostic radiology facilities and the most important factor for improvement is to increase awareness, both from reality of harm from unnecessary radiation exposure and with relative ease doses can be reduced. The study should therefore be implemented on the national scale as an approach to establish guidance levels of patient entrance surface dose for good medical practice and regular monitoring purposes. (author)

  10. Radiation doses to patients receiving computed tomography examinations in British Columbia

    International Nuclear Information System (INIS)

    Aldrich, J.E.; Bilawich, A.-M.; Mayo, J.R.

    2006-01-01

    To estimate the diagnostic reference levels and effective radiation dose to patients from routine computed tomography (CT) examinations in the province of British Columbia, Canada. The patient weight, height and computed tomography dose index or dose linear product (DLP) were recorded on study sheets for 1070 patients who were referred for clinically indicated routine CT examinations at 18 radiology departments in British Columbia. Sixteen of the scanners were multidetector row scanners. The average patient dose varied from hospital to hospital. The largest range was found for CT of the abdomen, for which the dose varied from 3.6 to 26.5 (average 10.1) mSv. For head CT, the range was 1.7 to 4.9 (average 2.8) mSv; for chest CT, it was 3.8 to 26 (average 9.3) mSv; for pelvis CT, it was 3.5 to 15.5 (average 9.0) mSv; and for abdomen/pelvis CT, it was 7.3 to 31.5 (average 16.3) mSv. Reference dose values were calculated for each exam. These DLP values are as follows: head, 1300 mGy cm; chest, 600 mGy cm; abdomen, 920 mGy cm; pelvis, 650 mGy cm; and abdomen/pelvis, 1100 mGy cm. Among hospitals, there was considerable variation in the DLP and patient radiation dose for a specific exam. Reference doses and patient doses were higher than those found in similar recent surveys carried out in the United Kingdom and the European Union. Patient doses were similar to those found in a recent survey in Germany. (author)

  11. Assessment of medical radiation exposure to patients and ambient doses in several diagnostic radiology departments

    Science.gov (United States)

    Sulieman, A.; Elhadi, T.; Babikir, E.; Alkhorayef, M.; Alnaaimi, M.; Alduaij, M.; Bradley, D. A.

    2017-11-01

    In many countries diagnostic medical exposures typically account for a very large fraction of the collective effective dose that can be assigned to anthropological sources and activities. This in part flags up the question of whether sufficient steps are being taken in regard to potential dose saving from such medical services. As a first step, one needs to survey doses to compare against those of best practice. The present study has sought evaluation of the radiation protection status and patient doses for certain key radiological procedures in four film-based radiology departments within Sudan. The radiation exposure survey, carried out using a survey meter and quality control test tools, involved a total of 299 patients their examinations being carried out at one or other of these four departments. The entrance surface air kerma (ESAK) was determined from exposure settings using DosCal software and an Unfors -Xi-meter. The mean ESAK for x-ray examination of the chest was 0.30±0.1 mGy, for the skull it was 0.96±0.7 mGy, for the abdomen 0.85±0.01 mGy, for spinal procedures 1.30±0.6 mGy and for procedures involving the limbs it was 0.43±0.3 mGy. Ambient dose-rates in the reception area, at the closed door of the x-ray room, recorded instantaneous values of up to 100 μSv/h. In regard to protection, the associated levels were found to be acceptable in three of the four departments, corrective action being required for one department, regular quality control also being recommended.

  12. Entrance surface dose and image quality: Comparison of adult chest and abdominal X-ray examinations in general practitioner clinics, public and private hospitals in Malaysia

    International Nuclear Information System (INIS)

    Hambali, A. S.; Ng, K. H.; Abdullah, B. J. J.; Wang, H. B.; Jamal, N.; Spelic, D. C.; Suleiman, O. H.

    2009-01-01

    This study was undertaken to compare the entrance surface dose (ESD) and image quality of adult chest and abdominal X-ray examinations conducted at general practitioner (GP) clinics, and public and private hospitals in Malaysia. The surveyed facilities were randomly selected within a given category (28 GP clinics, 20 public hospitals and 15 private hospitals). Only departmental X-ray units were involved in the survey. Chest examinations were done at all facilities, while only hospitals performed abdominal examinations. This study used the x-ray attenuation phantoms and protocols developed for the Nationwide Evaluation of X-ray Trends (NEXT) survey program in the United States. The ESD was calculated from measurements of exposure and clinical geometry. An image quality test tool was used to evaluate the low-contrast detectability and high-contrast detail performance under typical clinical conditions. The median ESD value for the adult chest X-ray examination was the highest (0.25 mGy) at GP clinics, followed by private hospitals (0.22 mGy) and public hospitals (0.17 mGy). The median ESD for the adult abdominal X-ray examination at public hospitals (3.35 mGy) was higher than that for private hospitals (2.81 mGy). Results of image quality assessment for the chest X-ray examination show that all facility types have a similar median spatial resolution and low-contrast detectability. For the abdominal X-ray examination, public hospitals have a similar median spatial resolution but larger low-contrast detectability compared with private hospitals. The results of this survey clearly show that there is room for further improvement in performing chest and abdominal X-ray examinations in Malaysia. (authors)

  13. Attainment of dosimetric pediatrics grandeur to computed tomography examinations of the abdomen

    International Nuclear Information System (INIS)

    Jormada, Tiago S.

    2013-01-01

    Currently, 10% of all computerized tomography exams (CT) are made in pediatric patients. In developed countries, the practice of obtaining the dosimetric quantities (weighted index dose C w , index air kerma volumetric C vol product kerma-length P KL , CT ) and effective dose (E) in pediatric CT scans is common. In Brazil, data like these are practically nonexistent. The goal of this work is to obtain the dosimetric quantities and the dose effective in pediatric CT scans, and study its application in the optimization process. The study took place in a thermographs' Toshiba Asteion Single-Slice and a GE Brightsped's multi-slice where measurements were made with type pencil ionization chamber and a trunk's phantom of PMMA with diameter of 16 cm. In single-slice CT scanner, the results obtained for the C vol , P KL , CT and E were 18.73 mGy, 15.61 mGy and 6.87 mSv mGy.cm 343.51, respectively, whereas in multi-slice CT scanner the results were 18.81 mGy, 20.07 mGy, 441.64 mGy.cm and 8,83 mSv. There was no significant difference between the values of C w obtained already in the values of the Cvol, P KL , CT and E dose the differences between the results were quite significant. Comparing the C w and P KL , CT and with the values recommended by UCRP 87 (25 mGy for C vol and 360 mGy.cm for P KL , CT in pediatric CT scans of the abdomen), the two scanners were below reference levels for C w and not require an start on process of optimization. (author)

  14. Estimation of effective dose during hysterosalpingography procedures

    International Nuclear Information System (INIS)

    Alzimamil, K.; Babikir, E.; Alkhorayef, M.; Sulieman, A.; Alsafi, K.; Omer, H.

    2014-08-01

    Hysterosalpingography (HSG) is the most frequently used diagnostic tool to evaluate the endometrial cavity and fallopian tube by using conventional x-ray or fluoroscopy. Determination of the patient radiation doses values from x-ray examinations provides useful guidance on where best to concentrate efforts on patient dose reduction in order to optimize the protection of the patients. The aims of this study were to measure the patients entrance surface air kerma doses (ESA K), effective doses and to compare practices between different hospitals in Sudan. ESA K were measured for patient using calibrated thermo luminance dosimeters (TLDs, Gr-200A). Effective doses were estimated using National Radiological Protection Board (NRPB) software. This study was conducted in five radiological departments: Two Teaching Hospitals (A and D), two private hospitals (B and C) and one University Hospital (E). The mean ESD was 20.1 mGy, 28.9 mGy, 13.6 mGy, 58.65 mGy, 35.7, 22.4 and 19.6 mGy for hospitals A,B,C,D, and E), respectively. The mean effective dose was 2.4 mSv, 3.5 mSv, 1.6 mSv, 7.1 mSv and 4.3 mSv in the same order. The study showed wide variations in the ESDs with three of the hospitals having values above the internationally reported values. Number of x-ray images, fluoroscopy time, operator skills x-ray machine type and clinical complexity of the procedures were shown to be major contributors to the variations reported. Results demonstrated the need for standardization of technique throughout the hospital. The results also suggest that there is a need to optimize the procedures. Local DRLs were proposed for the entire procedures. (author)

  15. EPR dosimetry of radiation background in the Urals region

    Energy Technology Data Exchange (ETDEWEB)

    Shishkina, E.A.; Degteva, M.O.; Shved, V.A. [Urals Research Center for Radiation Medicine, 48-A Vorovsky, Chelyabinsk 454076 (Russian Federation); Fattibene, P.; Onori, S. [Istituto Superiore di Sanita and Istituto Nazionale di Fisica Nucleare (Italy); Wieser, A. [GSF, Forschungszentrum fuer Umwelt und Gesundheit, Ingolstaedter Landstr (Germany); Ivanov, D.V.; Bayankin, S.N. [Institute of Metal Physics, Russian Academy of Sciences (Russian Federation); Knyazev, V.A.; Vasilenko, E.I.; Gorelov, M. [ZAO, Closed Corporation ' Company GEOSPETSECOLOGIA' (Russian Federation)

    2006-07-01

    Method of Electron Paramagnetic Resonance is extensively applied to individual retrospective dosimetry. The background dose is unavoidable component of cumulative absorbed dose in the tooth enamel accumulated during the lifetime of donor. Estimation of incidental radiation dose using tooth enamel needs in extraction of background dose. Moreover, the variation of background doses in the population is a limited factor for reliable detection of additional irradiation especially for low dose level. Therefore the accurate knowledge of the natural background radiation dose is a critical element of EPR studies of exposed populations. In the Urals region the method applies for such two large cohorts as the workers of Mayak (Ozersk citizens) and Techa River riverside inhabitants (rural population). Current study aimed to investigate the Urals radiation background detected by EPR spectrometry. For this aim two group of unexposed Urals residents were separated, viz: citizens of Ozersk and rural inhabitants of Chelyabinsk region. Comparison of two investigated territories has demonstrated that from the point of view of radiation background it is impossible to assume the Urals population as uniform. The reliable difference between the urban and rural residents has been found. The average background doses of Ozersk donors is in average 50 mGy higher than those detected for rural residents. The individual variability of background doses for Osersk has been higher than in the rural results. The difference in background dose levels between two population results in different limits of accidental dose detection and individualization. The doses for 'Mayak' workers (Ozyorsk citizens) can be classed as anthropogenic if the EPR measurements exceed 120 mGy for teeth younger than 40 years, and 240 mGy for teeth older than 70 years. The anthropogenic doses for Techa River residents (rural population) would be higher than 95 mGy for teeth younger than 50 years and 270 mGy for

  16. Parotid-Absorbed Doses: A Comparison Between Spiral Tomography and Panoramic

    Directory of Open Access Journals (Sweden)

    Ehsan Hekmatian

    2016-07-01

    Full Text Available Background Jaws spiral tomography and panoramic radiography have wide applications in dentistry, and the parotid gland is one of the most sensitive organs of the head and neck. Objectives The aim of this study was to evaluate and compare the parotid-absorbed dose in spiral tomography and panoramic radiographs using a thermoluminescent dosimeter. Materials and Methods A radiation analog dosimetry phantom was placed in a Cranex Tome radiograph device, and a parotid absorbed dose was measured in both techniques. Thermoluminescent dosimeters were placed bilaterally in the parotid region (on the tube side and the opposite side. Spiral tomography dosimetry was done for the upper and lower jaws in the anterior and posterior regions. Each region contained four slices of 2 mm and four slices of 4 mm in thickness. The results were analyzed by a Wilcoxon test. Results For the tube side parotid, the average absorbed doses in spiral tomography of the anterior and posterior parts of the maxilla and mandible, with the 2 mm slice thickness, were 1.70/1.40 and 1.65/1.60 mGy, respectively. The average absorbed doses with the 4mm slices were 1.65/1.70 and 1.75/1.57 mGy, respectively. For the opposite parotid, the average absorbed dose in spiral tomography of the anterior and posterior parts of the maxilla and mandible, with the 2 mm slice thickness, were 1.40/1.30 and 1.40/1.67 mGy, respectively. The average absorbed doses with the 4mm slices were 1.50/1.66 and 1.40/1.50 mGy, respectively. The average absorbed dose of the panoramic radiograph was 1.40 mGy. Conclusions There was no statistically significant difference in the parotid absorbed dose between spiral tomography and a panoramic radiograph (P value = 0.18. The overall results of this study were similar to other studies.

  17. Evidence for radiation induced crosslinking in polytetrafluoroethylene by means of high-resolution solid-state 19F high-speed MAS NMR

    International Nuclear Information System (INIS)

    Katoh, Etsuko; Sugisawa, Hisashi; Oshima, Akihiro; Tabata, Yoneho; Seguchi, Tadao; Yamazaki, Toshimasa

    1999-01-01

    Radiation effects on molecular structure of polytetrafluoroethylene (PTFE) were studied by high-resolution solid-state 19 F high speed magic angle spinning (HS MAS) NMR spectroscopy. Samples used for the NMR studies were prepared by electron beam irradiation of PTFE with a wide range of irradiation doses from 0.5-10 MGy in the molten state at 340 deg. C under oxygen-free atmosphere. While the non-irradiated PTFE displayed only an intense peak of the internal CF 2 , several new signals corresponding to CF 3 , CF 2 and CF groups were observed for the PTFE which was high temperature irradiated at 340 deg. C in oxygen-free atmosphere (hti-PTFE). Intensities of these new signals increased with an increase of irradiation dose. The present solid-state 19 F HS MAS NMR studies provide not only the first experimental evidence regarding the existence of crosslinking structure in hti-PTFE, directly detected as the CF signal, but also the crosslinking density which can be estimated from a proportion of the CF versus total fluorine signal intensities. The higher the irradiation dose, the higher the crosslinking density; hti-PTFE with 10 MGy contains one crosslinking site per approximately 24 CF 2 groups, while the hti-PTFE with 5 MGy contains one crosslinking site per approximately 36 CF 2 groups. Further, G value of crosslinking (G(x)) was estimated from the signal intensities of 19 F HS MAS NMR spectra. The highest G(x)-value, 1.85, was observed for the 2MGy hti-PTFE sample, suggesting that crosslinking of PTFE is formed most efficaciously with 2 MGy irradiation in the molten state at 340 deg. C under oxygen-free atmosphere

  18. Combined effects of alpha particles and depleted uranium on Zebrafish (Danio rerio) embryos

    International Nuclear Information System (INIS)

    Ng, Candy Y.P.; Pereira, Sandrine; Cheng, Shuk Han; Adam-Guillermin, Christelle; Garnier-Laplace, Jacqueline; Yu, Kwan Ngok

    2016-01-01

    The combined effects of low-dose or high-dose alpha particles and depleted uranium (DU) in Zebrafish (Danio rerio) embryos were studied. Three schemes were examined—(i) [I L U L ]: 0.44 mGy alpha-particle dose + 10 µg/l DU exposure, (ii) [I H U H ]: 4.4 mGy alpha-particle dose + 100 µg/l DU exposure and (iii) [I H U L ]: 4.4 mGy alpha-particle dose + 10 µg/l DU exposure—in which Zebrafish embryos were irradiated with alpha particles at 5 h post fertilization (hpf) and/or exposed to uranium at 5–6 hpf. The results were also compared with our previous work, which studied the effects of [I L U H ]: 0.44 mGy alpha-particle dose + 100 µg/l DU exposure. When the Zebrafish embryos developed to 24 hpf, the apoptotic signals in the entire embryos, used as the biological endpoint for this study, were quantified. Our results showed that [I L U L ] and [I H U L ] led to antagonistic effects, whereas [I H U H ] led to an additive effect. The effect found for the previously studied case of [I L U H ] was difficult to define because it was synergistic with reference to the 100 µg/l DU exposure, but it was antagonistic with reference to the 0.44 mGy alpha-particle dose. All the findings regarding the four different schemes showed that the combined effects critically depended on the dose response to each individual stressor. We also qualitatively explained these findings in terms of promotion of early death of cells predisposed to spontaneous transformation by alpha particles, interacting with the delay in cell death resulting from various concentrations of DU exposure

  19. Effect of continuous exposure to very low dose rates of gamma rays on life span and neoplasia in mice

    International Nuclear Information System (INIS)

    Tanaka, I.B. III; Tanaka, Satoshi; Ichinohe, Kazuaki; Matsumoto, Tsuneya; Otsu, Hiroshi; Oghiso, Yoichi; Sato, Fumiaki; Matsushita, Satoru

    2008-01-01

    Late effects of continuous exposure to ionizing radiation are potential hazards to workers in radiation facilities as well as to the general public. In the recent years, low-dose-rate and low-dose effects have become a serious concern. Using a total of 4,000 mice, we studied the late biological effects of chronic exposure to low-dose-rate radiation on life span and neoplasia. Two thousand male and 2000 female 8-week-old specific pathogen free (SPF) B6C3F1 mice were randomly divided into 4 groups, one non-irradiated (control) and three irradiated. The irradiated groups were exposed to 137 Cs gamma rays at dose-rates of 21, 1.1 and 0.05 mGy day -1 for approximately 400 days with total doses equivalent to 8000, 400 and 20 mGy, respectively. All mice were kept under SPF conditions until natural death and pathological examination was performed to determine the cause of death. Statistical analyses showed that the life spans of mice of both sexes irradiated with 21 mGy day -1 (P -1 (P 86.7% of all deaths. Compared to the non-irradiated controls, incidences of lethal neoplasms were significantly increased for myeloid leukaemia and hemangiosarcoma in males, soft tissue neoplasms and malignant granulosa cell tumors in females exposed to 21 mGy day -1 . The number of multiple primary neoplasms per mouse was significantly increased in mice irradiated at 21 mGy day -1 . Our results suggest that life shortening in mice continuously exposed to low dose-rate gamma rays is due to early death from a variety of neoplasms and not from increased incidence of specific lethal neoplasms. (author)

  20. Improving anxiety regulation in patients with breast cancer at the beginning of the survivorship period: a randomized clinical trial comparing the benefits of single-component and multiple-component group interventions.

    Science.gov (United States)

    Merckaert, Isabelle; Lewis, Florence; Delevallez, France; Herman, Sophie; Caillier, Marie; Delvaux, Nicole; Libert, Yves; Liénard, Aurore; Nogaret, Jean-Marie; Ogez, David; Scalliet, Pierre; Slachmuylder, Jean-Louis; Van Houtte, Paul; Razavi, Darius

    2017-08-01

    To compare in a multicenter randomized controlled trial the benefits in terms of anxiety regulation of a 15-session single-component group intervention (SGI) based on support with those of a 15-session multiple-component structured manualized group intervention (MGI) combining support with cognitive-behavioral and hypnosis components. Patients with nonmetastatic breast cancer were randomly assigned at the beginning of the survivorship period to the SGI (n = 83) or MGI (n = 87). Anxiety regulation was assessed, before and after group interventions, through an anxiety regulation task designed to assess their ability to regulate anxiety psychologically (anxiety levels) and physiologically (heart rates). Questionnaires were used to assess psychological distress, everyday anxiety regulation, and fear of recurrence. Group allocation was computer generated and concealed till baseline completion. Compared with patients in the SGI group (n = 77), patients attending the MGI group (n = 82) showed significantly reduced anxiety after a self-relaxation exercise (P = .006) and after exposure to anxiety triggers (P = .013) and reduced heart rates at different time points throughout the task (P = .001 to P = .047). The MGI participants also reported better everyday anxiety regulation (P = .005), greater use of fear of recurrence-related coping strategies (P = .022), and greater reduction in fear of recurrence-related psychological distress (P = .017) compared with the SGI group. This study shows that an MGI combining support with cognitive-behavioral techniques and hypnosis is more effective than an SGI based only on support in improving anxiety regulation in patients with breast cancer. Copyright © 2016 John Wiley & Sons, Ltd.

  1. Estimation of effective dose during hysterosalpingography procedures; Estimación de dosis efectiva durante los procedimientos hysterosalpingography

    Energy Technology Data Exchange (ETDEWEB)

    Alzimamil, K.; Babikir, E.; Alkhorayef, M. [King Saud University, College of Applied Medical Sciences, Radiological Sciences Department, P. O. Box 10219, Riyadh 11433, (Saudi Arabia); Sulieman, A. [Salman bin Abdulaziz University, College of Applied Medical Sciences, Radiology and Medical Imaging Department, P. O. Box 422, Alkharj (Saudi Arabia); Alsafi, K. [King Abdulaziz University, Faculty of Medicine, Radiology Department, Jeddah 22254 (Saudi Arabia); Omer, H., E-mail: kalzimami@ksu.edu.sa [Dammam University, Faculty of Medicine, Dammam Khobar Coastal Rd, Khobar 31982 (Saudi Arabia)

    2014-08-15

    Hysterosalpingography (HSG) is the most frequently used diagnostic tool to evaluate the endometrial cavity and fallopian tube by using conventional x-ray or fluoroscopy. Determination of the patient radiation doses values from x-ray examinations provides useful guidance on where best to concentrate efforts on patient dose reduction in order to optimize the protection of the patients. The aims of this study were to measure the patients entrance surface air kerma doses (ESA K), effective doses and to compare practices between different hospitals in Sudan. ESA K were measured for patient using calibrated thermo luminance dosimeters (TLDs, Gr-200A). Effective doses were estimated using National Radiological Protection Board (NRPB) software. This study was conducted in five radiological departments: Two Teaching Hospitals (A and D), two private hospitals (B and C) and one University Hospital (E). The mean ESD was 20.1 mGy, 28.9 mGy, 13.6 mGy, 58.65 mGy, 35.7, 22.4 and 19.6 mGy for hospitals A,B,C,D, and E), respectively. The mean effective dose was 2.4 mSv, 3.5 mSv, 1.6 mSv, 7.1 mSv and 4.3 mSv in the same order. The study showed wide variations in the ESDs with three of the hospitals having values above the internationally reported values. Number of x-ray images, fluoroscopy time, operator skills x-ray machine type and clinical complexity of the procedures were shown to be major contributors to the variations reported. Results demonstrated the need for standardization of technique throughout the hospital. The results also suggest that there is a need to optimize the procedures. Local DRLs were proposed for the entire procedures. (author)

  2. Non-induction of radioadaptive response in zebrafish embryos by neutrons

    International Nuclear Information System (INIS)

    Ng, Candy Y.P.; Kong, Eva Y.; Kobayashi, Alisa; Suya, Noriyoshi; Uchihori, Yukio; Cheng, Shuk Han; Konishi, Teruaki; Yu, Kwan Ngok

    2016-01-01

    In vivo neutron-induced radioadaptive response (RAR) was studied using zebrafish (Danio rerio) embryos. The Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility at the National Institute of Radiological Sciences (NIRS), Japan, was employed to provide 2-MeV neutrons. Neutron doses of 0.6, 1, 25, 50 and 100 mGy were chosen as priming doses. An X-ray dose of 2 Gy was chosen as the challenging dose. Zebrafish embryos were dechorionated at 4 h post fertilization (hpf), irradiated with a chosen neutron dose at 5 hpf and the X-ray dose at 10 hpf. The responses of embryos were assessed at 25 hpf through the number of apoptotic signals. None of the neutron doses studied could induce RAR. Non-induction of RAR in embryos having received 0.6- and 1-mGy neutron doses was attributed to neutron-induced hormesis, which maintained the number of damaged cells at below the threshold for RAR induction. On the other hand, non-induction of RAR in embryos having received 25-, 50- and 100-mGy neutron doses was explained by gamma-ray hormesis, which mitigated neutron-induced damages through triggering high-fidelity DNA repair and removal of aberrant cells through apoptosis. Separate experimental results were obtained to verify that high-energy photons could disable RAR. Specifically, 5- or 10-mGy X-rays disabled the RAR induced by a priming dose of 0.88 mGy of alpha particles delivered to 5-hpf zebrafish embryos against a challenging dose of 2 Gy of X-rays delivered to the embryos at 10 hpf

  3. Compression force and radiation dose in the Norwegian Breast Cancer Screening Program

    Energy Technology Data Exchange (ETDEWEB)

    Waade, Gunvor G.; Sanderud, Audun [Department of Life Sciences and Health, Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences, P.O. 4 St. Olavs Plass, 0130 Oslo (Norway); Hofvind, Solveig, E-mail: solveig.hofvind@kreftregisteret.no [Department of Life Sciences and Health, Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences, P.O. 4 St. Olavs Plass, 0130 Oslo (Norway); The Cancer Registry of Norway, P.O. 5313 Majorstuen, 0304 Oslo (Norway)

    2017-03-15

    Highlights: • Compression force and radiation dose for 17 951 screening mammograms were analyzed. • Large variations in mean applied compression force between the breast centers. • Limited associations between compression force and radiation dose. - Abstract: Purpose: Compression force is used in mammography to reduce breast thickness and by that decrease radiation dose and improve image quality. There are no evidence-based recommendations regarding the optimal compression force. We analyzed compression force and radiation dose between screening centers in the Norwegian Breast Cancer Screening Program (NBCSP), as a first step towards establishing evidence-based recommendations for compression force. Materials and methods: The study included information from 17 951 randomly selected screening examinations among women screened with equipment from four different venors at fourteen breast centers in the NBCSP, January-March 2014. We analyzed the applied compression force and radiation dose used on craniocaudal (CC) and mediolateral-oblique (MLO) view on left breast, by breast centers and vendors. Results: Mean compression force used in the screening program was 116N (CC: 108N, MLO: 125N). The maximum difference in mean compression force between the centers was 63N for CC and 57N for MLO. Mean radiation dose for each image was 1.09 mGy (CC: 1.04mGy, MLO: 1.14mGy), varying from 0.55 mGy to 1.31 mGy between the centers. Compression force alone had a negligible impact on radiation dose (r{sup 2} = 0.8%, p = < 0.001). Conclusion: We observed substantial variations in mean compression forces between the breast centers. Breast characteristics and differences in automated exposure control between vendors might explain the low association between compression force and radiation dose. Further knowledge about different automated exposure controls and the impact of compression force on dose and image quality is needed to establish individualised and evidence

  4. Optimal conditions of LDR to protect the kidney from diabetes

    Science.gov (United States)

    Cheng, Jie; Li, Fengsheng; Cui, Jiuwei; Guo, Weiying; Li, Cai; Li, Wei; Wang, Guixia; Xing, Xiao; Gao, Ying; Ge, Yuanyuan; Wang, Guanjun; Cai, Lu

    2014-01-01

    Aims We reported the attenuation of diabetes-induced renal dysfunction by exposure to multiple low-dose radiation (LDR) at 25 mGy every other day via suppressing renal oxidative damage. We here explored the optimal conditions of LDR to protect the kidney from diabetes. Main methods Type 1 diabetic mice were induced with multiple injections of low-dose streptozotocin in male C57BL/6J mice. Diabetic mice received whole body X-irradiation at dose of 12.5, 25 or 50 mGy every other day for either 4 or 8 weeks. Age-matched normal mice were similarly irradiated at the dose of 25 mGy for 4 or 8 weeks. The renal function and histopathological changes were examined at the 4th and 8th week of the study. Key findings Diabetes induced renal dysfunction, shown by the decreased creatinine and increased microalbumin in urinary. Renal oxidative damage, detected by protein nitration and lipid oxidation, and remodeling, reflected by increased expression of connective tissue growth factor, collagen IV and fibronectin, were significantly increased in diabetic mice. All these renal pathological and function changes in diabetic mice were significantly attenuated by exposure to LDR at all regimens, among which, however, exposure to LDR at 12.5 mGy for 8 weeks provided the best preventive effect on the kidney of diabetic mice. Significance Our results suggest that whole-body LDR at 12.5 mGy every other day for 8 weeks is the optimal condition of LDR to protect the kidney from diabetes. PMID:24631139

  5. Estimation of mean glandular dose for patients who undergo mammography and studying the factors affecting it

    Science.gov (United States)

    Barzanje, Sana L. N. H.; Harki, Edrees M. Tahir Nury

    2017-09-01

    The objective of this study was to determine mean glandular dose (MGD) during diagnostic mammography. This study was done in two hospitals in Hawler city in Kurdistan -region /Iraq, the exposure parameters kVp and mAs was recorded for 40 patients under go mammography. The MGD estimated by multiplied ESD with normalized glandular dose (Dn). The ESD measured indirectly by measuring output radiation mGy/mAs by using PalmRAD 907 as a suitable detector (Gigger detector).the results; shown that the mean and its standard deviation of MGD for Screen Film Mammography and Digital Mammography are (0.95±0.18)mGy and (0.99±0.26)mGy, respectively. And there is a significant difference between MGD for Screen Film Mammography and Digital Mammography views (p≤0. 05). Also the mean value and its standard deviation of MGD for screen film mammography is (0.96±0.21) for CC projection and (1.03±0.3) mGy for MLO projection, but mean value and its standard deviation evaluated of MGD for digital mammography is (0.92±0.17) mGy for CC projection and (0.98±0.2) mGy for MLO projection. As well as, the effect of kVp and mAs in MGD were studied, shows that in general as kVp and mAs increased the MGD increased accordingly in both of mammography systems.

  6. Evaluation of the peripheral dose in stereotactic radiotherapy and radiosurgery treatments

    International Nuclear Information System (INIS)

    Di Betta, Erika; Fariselli, Laura; Bergantin, Achille; Locatelli, Federica; Del Vecchio, Antonella; Broggi, Sara; Fumagalli, Maria Luisa

    2010-01-01

    Purpose: The main purpose of this work was to compare peripheral doses absorbed during stereotactic treatment of a brain lesion delivered using different devices. These data were used to estimate the risk of stochastic effects. Methods: Treatment plans were created for an anthropomorphic phantom and delivered using a LINAC with stereotactic cones and a multileaf collimator, a CyberKnife system (before and after a supplemental shielding was applied), a TomoTherapy system, and a Gamma Knife unit. For each treatment, 5 Gy were prescribed to the target. Measurements were performed with thermoluminescent dosimeters inserted roughly in the position of the thyroid, sternum, upper lung, lower lung, and gonads. Results: Mean doses ranged from of 4.1 (Gamma Knife) to 62.8 mGy (LINAC with cones) in the thyroid, from 2.3 (TomoTherapy) to 30 mGy (preshielding CyberKnife) in the sternum, from 1.7 (TomoTherapy) to 20 mGy (preshielding CyberKnife) in the upper part of the lungs, from 0.98 (Gamma Knife) to 15 mGy (preshielding CyberKnife) in the lower part of the lungs, and between 0.3 (Gamma Knife) and 10 mGy (preshielding CyberKnife) in the gonads. Conclusions: The peripheral dose absorbed in the sites of interest with a 5 Gy fraction is low. Although the risk of adverse side effects calculated for 20 Gy delivered in 5 Gy fractions is negligible, in the interest of optimum patient radioprotection, further studies are needed to determine the weight of each contributor to the peripheral dose.

  7. Patient dose in CT fluoroscopy examinations

    International Nuclear Information System (INIS)

    Ito, Yusuke; Kobayashi, Masanao; Kataoka, Yumi; Ida, Yoshihiro; Kato, Ryoichi; Katada, Kazuhiro; Asada, Yasuki; Suzuki, Shoichi

    2008-01-01

    CT fluoroscopy(CTF) results in a high dose for the area under investigation in comparison with other types of examination. On the basis of data from April 2005 to March 2008, we measured the X-ray doses at the target site in CTF of the lungs, lumbar vertebrae, and pelvis as well as the X-ray dose to the female reproductive organs, and calculated the effective dose. The CT equipment used was an Aquilion 16. TLDs were inserted into an anthropomorphic phantom in positions corresponding to the target sites and the reproductive organs. Standard tube voltage and tube current were used as measurement conditions, and the scanning time used was the average value for each type of examination during the two years. Dose measurements were taken in the following order: scanography, helical scan, CTF, helical scan. X-ray element calibration was carried out through reciprocal comparison made between an ionization chamber dosimeter corrected according to government standards and the TLD for each tube voltage used for measurement. Dose estimation software was used to calculate the effective doses. During the two years there were 136 CTF examinations. These included 43 scans of the lungs, 13 of lumbar vertebrae, and 18 of the pelvis. The X-ray doses were 0.1 mGy at both the ovaries and the uterus for lung scans, 2 mGy at the ovaries and 1 mGy at the uterus for lumbar vertebrae scans, and 40 mGy at the ovaries and 20 mGy at the uterus for pelvic scans. The effective dose was highest for the lumbar vertebrae, followed by the lungs and finally the pelvis. (author)

  8. SU-F-I-33: Estimating Radiation Dose in Abdominal Fat Quantitative CT

    Energy Technology Data Exchange (ETDEWEB)

    Li, X; Yang, K; Liu, B [Massachusetts General Hospital, Boston, MA (United States)

    2016-06-15

    Purpose: To compare size-specific dose estimate (SSDE) in abdominal fat quantitative CT with another dose estimate D{sub size,L} that also takes into account scan length. Methods: This study complied with the requirements of the Health Insurance Portability and Accountability Act. At our institution, abdominal fat CT is performed with scan length = 1 cm and CTDI{sub vol} = 4.66 mGy (referenced to body CTDI phantom). A previously developed CT simulation program was used to simulate single rotation axial scans of 6–55 cm diameter water cylinders, and dose integral of the longitudinal dose profile over the central 1 cm length was used to predict the dose at the center of one-cm scan range. SSDE and D{sub size,L} were assessed for 182 consecutive abdominal fat CT examinations with mean water-equivalent diameter (WED) of 27.8 cm ± 6.0 (range, 17.9 - 42.2 cm). Patient age ranged from 18 to 75 years, and weight ranged from 39 to 163 kg. Results: Mean SSDE was 6.37 mGy ± 1.33 (range, 3.67–8.95 mGy); mean D{sub size,L} was 2.99 mGy ± 0.85 (range, 1.48 - 4.88 mGy); and mean D{sub size,L}/SSDE ratio was 0.46 ± 0.04 (range, 0.40 - 0.55). Conclusion: The conversion factors for size-specific dose estimate in AAPM Report No. 204 were generated using 15 - 30 cm scan lengths. One needs to be cautious in applying SSDE to small length CT scans. For abdominal fat CT, SSDE was 80–150% higher than the dose of 1 cm scan length.

  9. The effects of rat's sperm bioassay for low dose X-ray

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Gye Hwan; Min, Soo Young; Lee, Sang Bock; Lee, Sam Yul; Lee, Jun Haeng [Nambu Univ., Gwangju (Korea, Republic of); Park, Jong Bae [Juseong College, Cheongwon (Korea, Republic of)

    2007-12-15

    In order to investigate the enhancement effects of low dose radiation on biological activation, this study applied low dose X-ray to the whole body of male rats to find out whether hormesis is induced in male germ cells. Total 36 Sprague-Dawley (SD) rats as experimental animal were subdivided into 6 groups(in 6 rats per group) such as control, 10 mGy, 20 mGy, 50 mGy, 100 mGy and 200 mGy radiation group. All the groups showed slightly increasing number of sperms per 0.1 g semen (14.216 x 10{sup 6}, 13.901 x 10{sup 6}, 14.153 x 10{sup 6}, 13.831 x 10{sup 6}, 14.137 x 10{sup 6}, 14.677 x 10{sup 6} respectively), and the motility of sperms amounted to 50.9%, 49.5%, 55.1%, 54.3%, 48.0% and 52.2% respectively. Particularly, compared to the control, the other 5 groups showed higher male hormone level, and the microscopic observations of testicle tissues showed no vacuolization in seminiferous tubules and testis cells. In the results of this experiment, no harmful effect was observed on Sprague-Dawley (SD) rats for which the dose of radiation was controlled as regulated legally by the Ministry of Science and Technology and the Ministry of Health and Welfare. However, as these results were obtained from a limited number of animals, we cannot maintain that the same effect will be observed in the human body. Therefore, there should be further research on the effect on other animals and ultimately on the human body.

  10. Evaluation of thyroid function in female subjects living in the high natural background radiation area of Karunagappally, Kerala

    International Nuclear Information System (INIS)

    Sreekumar, A.; Nair, Raghu Ram K.; Jayalakshmi, P.; Sebastian, P.; Akiba, S.

    2010-01-01

    Radiation exposure has been reported to cause non cancer thyroid abnormalities like diffuse goiter and thyroid nodules. The present study was undertaken to see if there are any morphological and functional changes taking place in the thyroid due to chronic low level radiation exposure. 257 female subjects living in the four high background radiation panchayats of Chavara, Neendakara, Alappad and Panmana were selected for the study after getting informed consent. 5 ml of blood was drawn from these subjects for assessing thyroid function. The subjects were all staying in the same area since their birth and had not moved out for more than one year at a stretch. The average age of the subjects was 40.5y with a range of 17-66y. The cumulative dose had a mean of 226.3 mGy and a range of 20.6-937.8 mGy. 95 subjects from the low background area of Oachira and Thevalakkara were selected as controls in the age group of 18-63y with a mean age of 47.1y. The mean cumulative dose of this group was 35.9 mGy with a minimum of 5.3 mGy and a maximum of 106.8 mGy. 5 ml blood was collected from these subjects for thyroid function studies. All the subjects underwent ultrasound examination of the thyroid using a 10 MHz frequency linear probe. The following parameters were studied to assess thyroid function: Free T4, TSH, Antithyroglobulin antibody (ATG), Parathyroid hormone. Ultrasound images showed the following common features: Normal - 171, Suggestive of Thyroiditis - 106, Multinodular Goitre - 63, Diffuse Goitre - 5, Solitary Nodule - 31. 73 subjects had elevated TSH and 190 subjects had raised ATG. A significant numbers of subjects had features of thyroiditis. A comparative evaluation with control subjects will be done to assess its significance with reference to cumulative dose

  11. The effects of rat's sperm bioassay for low dose X-ray

    International Nuclear Information System (INIS)

    Jin, Gye Hwan; Min, Soo Young; Lee, Sang Bock; Lee, Sam Yul; Lee, Jun Haeng; Park, Jong Bae

    2007-01-01

    In order to investigate the enhancement effects of low dose radiation on biological activation, this study applied low dose X-ray to the whole body of male rats to find out whether hormesis is induced in male germ cells. Total 36 Sprague-Dawley (SD) rats as experimental animal were subdivided into 6 groups(in 6 rats per group) such as control, 10 mGy, 20 mGy, 50 mGy, 100 mGy and 200 mGy radiation group. All the groups showed slightly increasing number of sperms per 0.1 g semen (14.216 x 10 6 , 13.901 x 10 6 , 14.153 x 10 6 , 13.831 x 10 6 , 14.137 x 10 6 , 14.677 x 10 6 respectively), and the motility of sperms amounted to 50.9%, 49.5%, 55.1%, 54.3%, 48.0% and 52.2% respectively. Particularly, compared to the control, the other 5 groups showed higher male hormone level, and the microscopic observations of testicle tissues showed no vacuolization in seminiferous tubules and testis cells. In the results of this experiment, no harmful effect was observed on Sprague-Dawley (SD) rats for which the dose of radiation was controlled as regulated legally by the Ministry of Science and Technology and the Ministry of Health and Welfare. However, as these results were obtained from a limited number of animals, we cannot maintain that the same effect will be observed in the human body. Therefore, there should be further research on the effect on other animals and ultimately on the human body

  12. Diagnostic accuracy at several reduced radiation dose levels for CT imaging in the diagnosis of appendicitis

    Science.gov (United States)

    Zhang, Di; Khatonabadi, Maryam; Kim, Hyun; Jude, Matilda; Zaragoza, Edward; Lee, Margaret; Patel, Maitraya; Poon, Cheryce; Douek, Michael; Andrews-Tang, Denise; Doepke, Laura; McNitt-Gray, Shawn; Cagnon, Chris; DeMarco, John; McNitt-Gray, Michael

    2012-03-01

    Purpose: While several studies have investigated the tradeoffs between radiation dose and image quality (noise) in CT imaging, the purpose of this study was to take this analysis a step further by investigating the tradeoffs between patient radiation dose (including organ dose) and diagnostic accuracy in diagnosis of appendicitis using CT. Methods: This study was IRB approved and utilized data from 20 patients who underwent clinical CT exams for indications of appendicitis. Medical record review established true diagnosis of appendicitis, with 10 positives and 10 negatives. A validated software tool used raw projection data from each scan to create simulated images at lower dose levels (70%, 50%, 30%, 20% of original). An observer study was performed with 6 radiologists reviewing each case at each dose level in random order over several sessions. Readers assessed image quality and provided confidence in their diagnosis of appendicitis, each on a 5 point scale. Liver doses at each case and each dose level were estimated using Monte Carlo simulation based methods. Results: Overall diagnostic accuracy varies across dose levels: 92%, 93%, 91%, 90% and 90% across the 100%, 70%, 50%, 30% and 20% dose levels respectively. And it is 93%, 95%, 88%, 90% and 90% across the 13.5-22mGy, 9.6-13.5mGy, 6.4-9.6mGy, 4-6.4mGy, and 2-4mGy liver dose ranges respectively. Only 4 out of 600 observations were rated "unacceptable" for image quality. Conclusion: The results from this pilot study indicate that the diagnostic accuracy does not change dramatically even at significantly reduced radiation dose.

  13. EPR dosimetry of radiation background in the Urals region

    International Nuclear Information System (INIS)

    Shishkina, E.A.; Degteva, M.O.; Shved, V.A.; Fattibene, P.; Onori, S.; Wieser, A.; Ivanov, D.V.; Bayankin, S.N.; Knyazev, V.A.; Vasilenko, E.I.; Gorelov, M.

    2006-01-01

    Method of Electron Paramagnetic Resonance is extensively applied to individual retrospective dosimetry. The background dose is unavoidable component of cumulative absorbed dose in the tooth enamel accumulated during the lifetime of donor. Estimation of incidental radiation dose using tooth enamel needs in extraction of background dose. Moreover, the variation of background doses in the population is a limited factor for reliable detection of additional irradiation especially for low dose level. Therefore the accurate knowledge of the natural background radiation dose is a critical element of EPR studies of exposed populations. In the Urals region the method applies for such two large cohorts as the workers of Mayak (Ozersk citizens) and Techa River riverside inhabitants (rural population). Current study aimed to investigate the Urals radiation background detected by EPR spectrometry. For this aim two group of unexposed Urals residents were separated, viz: citizens of Ozersk and rural inhabitants of Chelyabinsk region. Comparison of two investigated territories has demonstrated that from the point of view of radiation background it is impossible to assume the Urals population as uniform. The reliable difference between the urban and rural residents has been found. The average background doses of Ozersk donors is in average 50 mGy higher than those detected for rural residents. The individual variability of background doses for Osersk has been higher than in the rural results. The difference in background dose levels between two population results in different limits of accidental dose detection and individualization. The doses for 'Mayak' workers (Ozyorsk citizens) can be classed as anthropogenic if the EPR measurements exceed 120 mGy for teeth younger than 40 years, and 240 mGy for teeth older than 70 years. The anthropogenic doses for Techa River residents (rural population) would be higher than 95 mGy for teeth younger than 50 years and 270 mGy for teeth older

  14. Ultra low-dose chest CT using filtered back projection: Comparison of 80-, 100- and 120 kVp protocols in a prospective randomized study

    Energy Technology Data Exchange (ETDEWEB)

    Khawaja, Ranish Deedar Ali, E-mail: rkhawaja@mgh.harvard.edu [Division of Thoracic Radiology, MGH Imaging, Massachusetts General Hospital and Harvard Medical School, Boston (United States); Singh, Sarabjeet [Division of Thoracic Radiology, MGH Imaging, Massachusetts General Hospital and Harvard Medical School, Boston (United States); Madan, Rachna [Division of Thoracic Radiology, Brigham and Women' s Hospital and Harvard Medical School, Boston (United States); Sharma, Amita; Padole, Atul; Pourjabbar, Sarvenaz; Digumarthy, Subba; Shepard, Jo-Anne; Kalra, Mannudeep K. [Division of Thoracic Radiology, MGH Imaging, Massachusetts General Hospital and Harvard Medical School, Boston (United States)

    2014-10-15

    Highlights: • Filtered back projection technique enables acceptable image quality for chest CT examinations at 0.9 mGy (estimated effective dose of 0.5 mSv) for selected sizes of patients. • Lesion detection (such as solid non-calcified lung nodules) in lung parenchyma is optimal at 0.9 mGy, with limited visualization of thyroid nodules in FBP images. • Further dose reduction down to 0.4 mGy is possible for most patients undergoing follow-up chest CT for evaluation of larger lung nodules and GGOs. • Our results may help set the reference ALARA dose for chest CT examinations reconstructed with filtered back projection technique using the minimum possible radiation dose with acceptable image quality and lesion detection. - Abstract: Purpose: To assess lesion detection and diagnostic image quality of filtered back projection (FBP) reconstruction technique in ultra low-dose chest CT examinations. Methods and materials: In this IRB-approved ongoing prospective clinical study, 116 CT-image-series at four different radiation-doses were performed for 29 patients (age, 57–87 years; F:M – 15:12; BMI 16–32 kg/m{sup 2}). All patients provided written-informed-consent for the acquisitions of additional ultra low-dose (ULD) series on a 256-slice MDCT (iCT, Philips Healthcare). In-addition to their clinical standard-dose chest CT (SD, 120 kV mean CTDI{sub vol}, 6 ± 1 mGy), ULD-CT was subsequently performed at three-dose-levels (0.9 mGy [120 kV]; 0.5 mGy [100 kV] and 0.2 mGy [80 kV]). Images were reconstructed with FBP (2.5 mm * 1.25 mm) resulting into four-stacks: SD-FBP (reference-standard), FBP{sub 0.9}, FBP{sub 0.5}, and FBP{sub 0.2}. Four thoracic-radiologists from two-teaching-hospitals independently-evaluated data for lesion-detection and visibility-of-small-structures. Friedman's-non-parametric-test with post hoc Dunn's-test was used for data-analysis. Results: Interobserver-agreement was substantial between radiologists (k = 0.6–0.8). With

  15. Orthopaedic surgeries - assessment of ionising radiations exposure in health care workers

    International Nuclear Information System (INIS)

    Leite, E.S.; Uva, A.S.

    2006-01-01

    Full text of publication follows: 1. Objectives: The health care workers are exposed to ionizing radiations during their activities. In the operating rooms, the ionizing radiations are used in orthopaedic surgery and the dose depends on some factors, like the characteristics of the equipment. This study aims to: Estimate the occupational dose of ionizing radiations exposure of the orthopaedic doctors and nurses during the orthopaedic surgeries, in a Portuguese operating room; Sensitize the health care workers to use the individual dosimeter and to adopt radiation preventive measures. 2. Population and methods The study was conducted on nine Orthopaedic doctors and two nurses of an operating room of a hospital in Lisbon neighborhoods. We made a risk evaluating concerning: the radiations dose in different points, corresponding to gonads, hands and crystalline lens levels of all the professionals, during the surgeries; the average period of radiation in the orthopaedic surgeries; the number of annual orthopaedic surgeries, looking for that in the surgeries registers, to estimate the annual ionizing radiations dose of each orthopaedic doctor and nurse. 3. Results The annual doses estimated at different levels for orthopaedic doctors were the following: gonads: between 20,63 and 68,75 mGy; hands: 4,95 16,50 mGy; crystalline lens: 8,25 27,50 mGy). For the orthopaedic nurses: gonads: 130,63 151,25 mGy; hands: 31,35 36,30 mGy; crystalline lens 52,25 60,25 mGy. 4. Conclusions Although the location and positions of health care workers are not the same during the different surgeries and the equipment has an automatic control of the X ray emission, the annual ionizing radiations dose exposure for health care workers is an important one. The risk rating justifies the use of individual dosimeters for better individual dose assessment as part of an ionizing radiations prevention program. As a matter of fact preventive measures begin with a good quantitative risk assessment of

  16. Assessment of mean glandular dose for patients in mammography in some Hospitals in Khartoum state

    International Nuclear Information System (INIS)

    Abu Elmola, Alaa Mahdi

    2016-12-01

    A mammography examination facilitates the early detection of breast cancer. However, the potential risk of radiation- induced carcinogenesis is also increased with such a procedure. Thus assessment of the breast dose is important. The objective of this study was to determine the mean glandular dose (MGD) resulting from cranio caudal(CC) and mediolateral oblique (MLO) views in one breast and the total dose per woman in Sudan, and to identify the factors affecting it. Measurements were performed to estimate mean glandular doses for 60 patients who underwent mammography examination in two clinics in Khartoum, Sudan.Doses were studied in RCH and NDC, centers which were using computed radiography(CR)devices. The piranha system was used for determining the MGD in this work. The characteristics of the radiographic equipment and the exposure data of each patient were recorded using designed format. The MGD was calculated from the measured incident Air kerma using appropriate conversion coefficients. The range of CBT was (1-7)cm for two projections. The respective averages for the CC and MLO projections were (4.55±1.38)mGy and (4.15±1.33) mGy, respectively. The average MGD per image was (4.3±1.35)mGy. The MGD per women was (8.6±1.35)mGy. The mean±SD MGD per image in the present study was lower than most of similar reports. The average MGD values recorded in this study were above the limiting value of the Institute of Physical Sciences in Medicine(2.0 mGy) and American College of Radiology (3.0 mGy recommendation. This suggests that mammography x-ray generators in this case are not capable of achieving acceptable dose levels for patients safety. Therefore, with consideration of all other factors, quality control program tests must be carried out periodically and frequently of the mammography equipment.(Author)

  17. WE-D-18A-04: How Iterative Reconstruction Algorithms Affect the MTFs of Variable-Contrast Targets in CT Images

    Energy Technology Data Exchange (ETDEWEB)

    Dodge, C.T.; Rong, J. [MD Anderson Cancer Center, Houston, TX (United States); Dodge, C.W. [Methodist Hospital, Houston, TX (United States)

    2014-06-15

    Purpose: To determine how filtered back-projection (FBP), adaptive statistical (ASiR), and model based (MBIR) iterative reconstruction algorithms affect the measured modulation transfer functions (MTFs) of variable-contrast targets over a wide range of clinically applicable dose levels. Methods: The Catphan 600 CTP401 module, surrounded by an oval, fat-equivalent ring to mimic patient size/shape, was scanned on a GE HD750 CT scanner at 1, 2, 3, 6, 12 and 24 mGy CTDIvol levels with typical patient scan parameters: 120kVp, 0.8s, 40mm beam width, large SFOV, 2.5mm thickness, 0.984 pitch. The images were reconstructed using GE's Standard kernel with FBP; 20%, 40% and 70% ASiR; and MBIR. A task-based MTF (MTFtask) was computed for six cylindrical targets: 2 low-contrast (Polystyrene, LDPE), 2 medium-contrast (Delrin, PMP), and 2 high-contrast (Teflon, air). MTFtask was used to compare the performance of reconstruction algorithms with decreasing CTDIvol from 24mGy, which is currently used in the clinic. Results: For the air target and 75% dose savings (6 mGy), MBIR MTFtask at 5 lp/cm measured 0.24, compared to 0.20 for 70% ASiR and 0.11 for FBP. Overall, for both high-contrast targets, MBIR MTFtask improved with increasing CTDIvol and consistently outperformed ASiR and FBP near the system's Nyquist frequency. Conversely, for Polystyrene at 6 mGy, MBIR (0.10) and 70% ASiR (0.07) MTFtask was lower than for FBP (0.18). For medium and low-contrast targets, FBP remains the best overall algorithm for improved resolution at low CTDIvol (1–6 mGy) levels, whereas MBIR is comparable at higher dose levels (12–24 mGy). Conclusion: MBIR improved the MTF of small, high-contrast targets compared to FBP and ASiR at doses of 50%–12.5% of those currently used in the clinic. However, for imaging low- and mediumcontrast targets, FBP performed the best across all dose levels. For assessing MTF from different reconstruction algorithms, task-based MTF measurements are necessary.

  18. The evaluation of the performance of the automatic exposure control system of some selected mammography facilities in the Greater Accra Region, Ghana

    International Nuclear Information System (INIS)

    Amesimenu, R.

    2013-07-01

    dark films also accounted for film reject signifying the need for continuous training for radiographers and an effective quality control programme. Estimated mean glandular dose (MGD) of values 1.0 mGy, 1.3 mGy, 1.1 mGy and 1.1 mGy at 28 KV for the selected facilities were less than 2 mGy and 3 mGy per the recommendation of International Atomic Energy Agency (IAEA) and American College of Radiology (ACR) respectively. Management of mammography facilities must establish an effective quality management system which must be implemented and continually improved to enhance radiological services delievered to patients as well as improve radiation protection of patients. (au)

  19. Radiation dose levels in pediatric chest CT: experience in 499 children evaluated with dual-source single-energy CT

    Energy Technology Data Exchange (ETDEWEB)

    Martine, Remy-Jardin; Colas, Lucie; Jean-Baptiste, Faivre; Remy, Jacques [CHU Lille (EA 2694) University of Lille, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Santangelo, Teresa [CHU Lille (EA 2694) University of Lille, Department of Thoracic Imaging, Hospital Calmette, Lille (France); Bambino Gesu Children' s Hospital, Department of Imaging, Rome (Italy); Duhamel, Alain [University of Lille (EA 2694), Department of Biostatistics, CHU Lille, Lille (France); Deschildre, Antoine [CHU Lille - University of Lille, Department of Pediatric Pulmonology, Lille (France)

    2017-02-15

    The availability of dual-source technology has introduced the possibility of scanning children at lower kVp with a high-pitch mode, combining high-speed data acquisition and high temporal resolution. To establish the radiation dose levels of dual-source, single-energy chest CT examinations in children. We retrospectively recorded the dose-length product (DLP) of 499 consecutive examinations obtained in children <50 kg, divided into five weight groups: group 1 (<10 kg, n = 129); group 2 (10-20 kg, n = 176); group 3 (20-30 kg, n = 99), group 4 (30-40 kg, n = 58) and group 5 (40-49 kg, n = 37). All CT examinations were performed with high temporal resolution (75 ms), a high-pitch mode and a weight-adapted selection of the milliamperage. CT examinations were obtained at 80 kVp with a milliamperage ranging between 40 mAs and 90 mAs, and a pitch of 2.0 (n = 162; 32.5%) or 3.0 (n = 337; 67.5%). The mean duration of data acquisition was 522.8 ± 192.0 ms (interquartile range 390 to 610; median 490). In the study population, the mean CT dose index volume (CTDIvol{sub 32}) was 0.83 mGy (standard deviation [SD] 0.20 mGy; interquartile range 0.72 to 0.94; median 0.78); the mean DLP{sub 32} was 21.4 mGy.cm (SD 9.1 mGy.cm; interquartile range 15 to 25; median 19.0); and the mean size-specific dose estimate (SSDE) was 1.7 mGy (SD 0.4 mGy; interquartile range 1.5 to 1.9; median 1.7). The DLP{sub 32}, CTDI{sub vol32} and SSDE were found to be statistically significant in the five weight categories (P < 0.0001). This study establishes the radiation dose levels for dual-source, single-kVp chest CT from a single center. In the five weight categories, the median values varied 15-37 mGy.cm for the DLP{sub 32}, 0.78-1.25 mGy for the CTDI{sub vol32} and 1.6-2.1 mGy for the SSDE. (orig.)

  20. STUDY OF THE SEDIMENTATION TREND IN THE PROSPECTIVE AREA OF PORT OF MARINE CENTER, CIREBON BASED ON REMOTE SENSING DATA

    Directory of Open Access Journals (Sweden)

    Undang Hernawan

    2017-07-01

    Full Text Available A coastal zone is the interface between the land and water that influenced by both of them. Coastal dynamic is influenced by many factors from land and sea, such as sedimentation and current. In order to support marine facility, Marine Geological Institute of Indonesia (MGI plan to build a port. The prospective area is behind MGI office at Cirebon. This study use multi temporal remote sensing data in order to observe trend of coastline change around MGI. Based on the interpretation of the data, there are sedimentation around the MGI water and abrasion due to the presence of Kejawanan’s jetty and Kalijaga River. The result also shows that the current in this region is moving from southeast to northwest. The presence of the Kejawanan’s jetty stymies the movement of sediment. The sediment which is normally moving to the north of the jetty is then trapped on the south side of the structure, so that the sediment precipitates in this region and makes it as the active region of sedimentation and accretion. The presence mangrove conduces to support sedimentation speed and accretion at this region, because of his function as the catchment area. Abrasion occurs in the eastern part of MGI office at the Kalijaga river mouth within the bay. The Kalijaga River mouth is predicted to be the primary source of sedimentation in this area. The coastline change caused by sedimentation will be continuing as long as it is supplied by the sediment. The direction of the sedimentation is parallel to the jetty and it forms ellipsoid, with the sedimentation/accretion region is behind MGI office. The abrasion area is found in Kalijaga River mouth and a small area beside Kalijaga River. In order to build a port, we have to consider this sedimentation process. One of the alternatives to build the port is to make a quay pile model which gives way the current to pass through the other side of the port. Another alternative is to build the port as a pond model but

  1. Image evaluation and exposure dose with the application of tube voltage and adaptive statistical iterative reconstruction of low dose computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Tae Joon [Dept. of Radiology, Konkuk University Medical Center, Seoul (Korea, Republic of); Kim, Ki Jeong [Dept. of Radiology, Wonkwang University Hospital, Iksan (Korea, Republic of); Lee, Hye Nam [Dept. of Radiology, Gimsangyeong Internal Medicine Clinic, Nonsan (Korea, Republic of)

    2017-06-15

    The study has attempted to evaluate and compare the image evaluation and exposure dose by respectively applying filter back projection (FBP), the existing test method, and adaptive statistical iterative reconstruction (ASIR) with different values of tube voltage during the low dose computed tomography (LDCT). With the image reconstruction method as basis, chest phantom was utilized with the FBP and ASIR set at 10%, 20% respectively, and the change of tube voltage (100 kVp, 120 kVp). For image evaluation, back ground noise, signal-noise ratio (SNR) and contrast-noise ratio (CNR) were measured, and, for dose assessment, CTDIvol and DLP were measured respectively. In terms of image evaluation, there was significant difference in ascending aorta (AA) SNR and inpraspinatus muscle (IM) SNR with the different amount of tube voltage (p < 0.05). In terms of CTDIvol, the measured values with the same tube voltage of 120 kVp were 2.6 mGy with no-ASIR and 2.17 mGy with 20%-ASIR respectively, decreased by 0.43 mGy, and the values with 100 kVp were 1.61 mGy with no-ASIR and 1.34 mGy with 20%-ASIR, decreased by 0.27 mGy. In terms of DLP, the measured values with 120 kVp were 103.21 mGy‧cm with no-ASIR and 85.94 mGy‧cm with 20%-ASIR, decreased by 17.27mGy‧cm (about 16.7%), and the values with 100 kVp were 63.84 mGy‧cm with no-ASIR and 53.25 mGy‧cm with 20%-ASIR, a decrease by 10.62 mGy‧cm ( about 16.7%). At lower tube voltage, the rate of dose significantly decreased, but the negative effects on image evaluation was shown due to the increase of noise.

  2. TU-D-209-01: Dosimetry of Diagnostic Work Up Mammography

    Energy Technology Data Exchange (ETDEWEB)

    Jallow, N [Emory University, Atlanta, GA (United States); Sechopoulos, I [Radboud University Medical Centre, Nijmegen (Netherlands)

    2016-06-15

    Purpose: To investigate patient average glandular dose (AGD) characteristics of diagnostic mammography. Methods: The techniques used to image 14420 patients who received diagnostic work up mammography from October 2008 to December 2014 at one academic hospital were retrospectively collected. The most common diagnostic views and the techniques used for each according to compressed breast thickness were determined. For all techniques, 1st half value layer and air kerma output per tube current-exposure time product were measured; then the incident air kerma for each acquisition was calculated. The values for normalized glandular dose (DgN) were obtained with a validated Monte Carlo simulation of mammographic acquisition. The mono-energetic DgN results were combined according to relative fluence using the TASMICS model to obtain DgN coefficients for each spectrum. The spectral DgN and calculated incident air kerma were used to estimate AGD of patients with breast thickness ranging from 2 to 8 cm. Results: The most common views utilized during diagnostic mammography were magnification craniocaudal (24%), magnification mediolateral (19%), spot craniocaudal (28%), and spot mediolateral oblique (24%). The AGD increased with increasing breast thickness for both the magnification and spot views. The AGD for a 5.5 cm thick breast was approximately 6.8 mGy and 2.2 mGy for the magnification and spot views, respectively. The AGD ranged from 3.6 mGy to 6.8 mGy for the magnification views and from 1.0 mGy to 3.1 mGy for spot views. The difference in AGD between the two magnification views or the two spot views was not significant. Conclusion: These results provide information on breast dose to which screening recalled women are exposed to. In addition to understanding the dose used for common clinical imaging tests, this data could be used when comparing use of mammography for diagnostic workup to other potential modalities, such as breast tomosynthesis and breast CT.

  3. A completed audit cycle of the lateral scan projection radiograph in CT pulmonary angiography (CTPA); the impact on scan length and radiation dose

    International Nuclear Information System (INIS)

    Rodrigues, J.C.L.; Negus, I.S.; Manghat, N.E.; Hamilton, M.C.K.

    2013-01-01

    Aim: To investigate the effect of incorporating a lateral scan projection radiograph (topogram) in addition to the standard frontal topogram on excess scan length in computed tomography pulmonary angiography (CTPA) and to quantify the impact on effective dose. Materials and methods: Fifty consecutive patients referred for exclusion of pulmonary embolism who had undergone a CTPA examination with conventional frontal topogram to plan scan length (protocol A) were compared with 50 consecutive patients who had undergone a CTPA study with frontal and additional lateral topogram for planning (protocol B) in a retrospective audit. Optimal scan length was defined from lung apex to lung base. Mean excess scan length beyond these landmarks was determined. The mean organ doses to the thyroid, liver, and stomach, as well as mean effective dose, were estimated using standard conversion factors. Results: The mean excess scan length was significantly lower in protocol B compared to the protocol A cohort (19.5 ± 17.4 mm [mean ± standard deviation] versus 39.1 ± 20.4 mm, p < 0.0001). The mean excess scan length below the lung bases was significantly lower in the protocol B cohort compared to the protocol A group (7.5 ± 12.7 mm versus 23 ± 16.6 mm, p < 0.0001), as were the mean organ doses to the stomach (4.24 ± 0.81 mGy versus 5.22 ± 1.06 mGy, p < 0.0001) and liver (5.60 ± 0.64 mGy versus 6.38 ± 0.81 mGy, p < 0.0001). A non-significant reduction in over-scanning above the apices in protocol B was observed compared with protocol A (12 ± 8.8 mm versus 16.2 ± 13.6 mm, p = 0.07), which equated to lower mean thyroid organ dose in (3.28 ± 1.76 mGy versus 4.11 ± 3.11 mGy, p = 0.104). Conclusion: The present audit indicates that incorporation of a lateral topogram into the CTPA protocol, together with radiographer education, reduces excess scan length, which significantly reduces the dose to the liver and stomach, and potentially lowers the dose to the thyroid. This simple

  4. Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms.

    Science.gov (United States)

    Koivisto, Juha H; Wolff, Jan E; Kiljunen, Timo; Schulze, Dirk; Kortesniemi, Mika

    2015-07-08

    The aims of this study were to characterize reinforced metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low-dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50-90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point-dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, k = 2) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low-dose limit. The sensitivity was 3.09 ± 0.13 mV/mGy independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was -8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD-comparable low-dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However, for single in

  5. External dose reconstruction in tooth enamel of Techa riverside residents

    Energy Technology Data Exchange (ETDEWEB)

    Shishkina, E.A.; Volchkova, A.Yu.; Krivoschapov, V.A.; Degteva, M.O. [Urals Research Center for Radiation Medicine, Chelyabinsk (Russian Federation); Timofeev, Y.S.; Zalyapin, V.I. [Southern Urals State University, Chelyabinsk (Russian Federation); Fattibene, P.; Della Monaca, S.; De Coste, V. [Istituto Superiore di Sanita e Istituto Nazionale di Fisica Nucleare, Rome (Italy); Wieser, A. [Helmholtz Zentrum Muenchen, German Research Centre for Environmental Health, Neuherberg (Germany); Ivanov, D.V. [M.N. Mikheev Institute of Metal Physics, Ural Division of the Russian Academy of Sciences, Ekaterinburg (Russian Federation); Ural Federal University, Yekaterinburg (Russian Federation); Anspaugh, L.R. [University of Utah, Salt Lake City, UT (United States)

    2016-11-15

    This study summarizes the 20-year efforts for dose reconstruction in tooth enamel of the Techa riverside residents exposed to ionizing radiation as a result of radionuclide releases into the river in 1949-1956. It represents the first combined analysis of all the data available on EPR dosimetry with teeth of permanent residents of the Techa riverside territory. Results of electron paramagnetic resonance (EPR) measurements of 302 teeth donated by 173 individuals living permanently in Techa riverside settlements over the period of 1950-1952 were analyzed. These people were residents of villages located at the free-flowing river stream or at the banks of stagnant reservoirs such as ponds or blind river forks. Cumulative absorbed doses measured using EPR are from several sources of exposure, viz., background radiation, internal exposure due to bone-seeking radionuclides ({sup 89}Sr, {sup 90}Sr/{sup 90}Y), internal exposure due to {sup 137}Cs/{sup 137m}Ba incorporated in soft tissues, and anthropogenic external exposure. The purpose of the present study was to evaluate the contribution of different sources of enamel exposure and to deduce external doses to be used for validation of the Techa River Dosimetry System (TRDS). Since various EPR methods were used, harmonization of these methods was critical. Overall, the mean cumulative background dose was found to be 63 ± 47 mGy; cumulative internal doses due to {sup 89}Sr and {sup 90}Sr/{sup 90}Y were within the range of 10-110 mGy; cumulative internal doses due to {sup 137}Cs/{sup 137m}Ba depend on the distance from the site of releases and varied from 1 mGy up to 90 mGy; mean external doses were maximum for settlements located at the banks of stagnant reservoirs (∝500 mGy); in contrast, external doses for settlements located along the free-flowing river stream did not exceed 160 mGy and decreased downstream with increasing distance from the site of release. External enamel doses calculated using the TRDS code and

  6. Health effect of low dose/low dose rate radiation

    International Nuclear Information System (INIS)

    Kodama, Seiji

    2012-01-01

    The clarified and non-clarified scientific knowledge is discussed to consider the cause of confusion of explanation of the title subject. The low dose is defined roughly lower than 200 mGy and low dose rate, 0.05 mGy/min. The health effect is evaluated from 2 aspects of clinical symptom/radiation hazard protection. In the clinical aspect, the effect is classified in physical (early and late) and genetic ones, and is classified in stochastic (no threshold value, TV) and deterministic (with TV) ones from the radioprotection aspect. Although the absence of TV in the carcinogenic and genetic effects has not been proved, ICRP employs the stochastic standpoint from the safety aspect for radioprotection. The lowest human TV known now is 100 mGy, meaning that human deterministic effect would not be generated below this dose. Genetic deterministic effect can be observable only in animal experiments. These facts suggest that the practical risk of exposure to <100 mGy in human is the carcinogenesis. The relationship between carcinogenic risk in A-bomb survivors and their exposed dose are found fitted to the linear no TV model, but the epidemiologic data, because of restriction of subject number analyzed, do not always mean that the model is applicable even below the dose <100 mGy. This would be one of confusing causes in explanation: no carcinogenic risk at <100 mGy or risk linear to dose even at <100 mGy, neither of which is scientifically conclusive at present. Also mentioned is the scarce risk of cancer in residents living in the high background radiation regions in the world in comparison with that in the A-bomb survivors exposed to the chronic or acute low dose/dose rate. Molecular events are explained for the low-dose radiation-induced DNA damage and its repair, gene mutation and chromosome aberration, hypothesis of carcinogenesis by mutation, and non-targeting effect of radiation (bystander effect and gene instability). Further researches to elucidate the low dose

  7. Comparative proteomic analysis of rice after seed ground simulated radiation and spaceflight explains the radiation effects of space environment

    Science.gov (United States)

    Wang, Wei; Shi, Jinming; Liang, Shujian; Lei, Huang; Shenyi, Zhang; Sun, Yeqing

    In previous work, we compared the proteomic profiles of rice plants growing after seed space-flights with ground controls by two-dimensional difference gel electrophoresis (2-D DIGE) and found that the protein expression profiles were changed after seed space environment exposures. Spaceflight represents a complex environmental condition in which several interacting factors such as cosmic radiation, microgravity and space magnetic fields are involved. Rice seed is in the process of dormant of plant development, showing high resistance against stresses, so the highly ionizing radiation (HZE) in space is considered as main factor causing biological effects to seeds. To further investigate the radiation effects of space environment, we performed on-ground simulated HZE particle radiation and compared between the proteomes of seed irra-diated plants and seed spaceflight (20th recoverable satellite) plants from the same rice variety. Space ionization shows low-dose but high energy particle effects, for searching the particle effects, ground radiations with the same low-dose (2mGy) but different liner energy transfer (LET) values (13.3KeV/µm-C, 30KeV/µm-C, 31KeV/µm-Ne, 62.2KeV/µm-C, 500Kev/µm-Fe) were performed; using 2-D DIGE coupled with clustering and principle component analysis (PCA) for data process and comparison, we found that the holistic protein expression patterns of plants irradiated by LET-62.2KeV/µm carbon particles were most similar to spaceflight. In addition, although space environment presents a low-dose radiation (0.177 mGy/day on the satellite), the equivalent simulated radiation dose effects should still be evaluated: radiations of LET-62.2KeV/µm carbon particles with different cumulative doses (2mGy, 20mGy, 200mGy, 2000mGy) were further carried out and resulted that the 2mGy radiation still shared most similar proteomic profiles with spaceflight, confirming the low-dose effects of space radiation. Therefore, in the protein expression level

  8. Adaptive statistical iterative reconstruction: reducing dose while preserving image quality in the pediatric head CT examination.

    Science.gov (United States)

    McKnight, Colin D; Watcharotone, Kuanwong; Ibrahim, Mohannad; Christodoulou, Emmanuel; Baer, Aaron H; Parmar, Hemant A

    2014-08-01

    Over the last decade there has been escalating concern regarding the increasing radiation exposure stemming from CT exams, particularly in children. Adaptive statistical iterative reconstruction (ASIR) is a relatively new and promising tool to reduce radiation dose while preserving image quality. While encouraging results have been found in adult head and chest and body imaging, validation of this technique in pediatric population is limited. The objective of our study was to retrospectively compare the image quality and radiation dose of pediatric head CT examinations obtained with ASIR compared to pediatric head CT examinations without ASIR in a large patient population. Retrospective analysis was performed on 82 pediatric head CT examinations. This group included 33 pediatric head CT examinations obtained with ASIR and 49 pediatric head CT examinations without ASIR. Computed tomography dose index (CTDIvol) was recorded on all examinations. Quantitative analysis consisted of standardized measurement of attenuation and the standard deviation at the bilateral centrum semiovale and cerebellar white matter to evaluate objective noise. Qualitative analysis consisted of independent assessment by two radiologists in a blinded manner of gray-white differentiation, sharpness and overall diagnostic quality. The average CTDIvol value of the ASIR group was 21.8 mGy (SD = 4.0) while the average CTDIvol for the non-ASIR group was 29.7 mGy (SD = 13.8), reflecting a statistically significant reduction in CTDIvol in the ASIR group (P ASIR group as compared to the 3- to 12-year-old non-ASIR group (21.5 mGy vs. 30.0 mGy; P = 0.004) as well as statistically significant reductions in CTDI for the >12-year-old ASIR group as compared to the >12-year-old non-ASIR group (29.7 mGy vs. 49.9 mGy; P = 0.0002). Quantitative analysis revealed no significant difference in the homogeneity of variance in the ASIR group compared to the non-ASIR group. Radiologist assessment of

  9. Adaptive statistical iterative reconstruction: reducing dose while preserving image quality in the pediatric head CT examination

    Energy Technology Data Exchange (ETDEWEB)

    McKnight, Colin D.; Watcharotone, Kuanwong; Ibrahim, Mohannad; Christodoulou, Emmanuel; Baer, Aaron H.; Parmar, Hemant A. [University of Michigan, Department of Radiology, Ann Arbor, MI (United States)

    2014-08-15

    Over the last decade there has been escalating concern regarding the increasing radiation exposure stemming from CT exams, particularly in children. Adaptive statistical iterative reconstruction (ASIR) is a relatively new and promising tool to reduce radiation dose while preserving image quality. While encouraging results have been found in adult head and chest and body imaging, validation of this technique in pediatric population is limited. The objective of our study was to retrospectively compare the image quality and radiation dose of pediatric head CT examinations obtained with ASIR compared to pediatric head CT examinations without ASIR in a large patient population. Retrospective analysis was performed on 82 pediatric head CT examinations. This group included 33 pediatric head CT examinations obtained with ASIR and 49 pediatric head CT examinations without ASIR. Computed tomography dose index (CTDI{sub vol}) was recorded on all examinations. Quantitative analysis consisted of standardized measurement of attenuation and the standard deviation at the bilateral centrum semiovale and cerebellar white matter to evaluate objective noise. Qualitative analysis consisted of independent assessment by two radiologists in a blinded manner of gray-white differentiation, sharpness and overall diagnostic quality. The average CTDI{sub vol} value of the ASIR group was 21.8 mGy (SD = 4.0) while the average CTDI{sub vol} for the non-ASIR group was 29.7 mGy (SD = 13.8), reflecting a statistically significant reduction in CTDI{sub vol} in the ASIR group (P < 0.01). There were statistically significant reductions in CTDI for the 3- to 12-year-old ASIR group as compared to the 3- to 12-year-old non-ASIR group (21.5 mGy vs. 30.0 mGy; P = 0.004) as well as statistically significant reductions in CTDI for the >12-year-old ASIR group as compared to the >12-year-old non-ASIR group (29.7 mGy vs. 49.9 mGy; P = 0.0002). Quantitative analysis revealed no significant difference in the

  10. WE-D-18A-04: How Iterative Reconstruction Algorithms Affect the MTFs of Variable-Contrast Targets in CT Images

    International Nuclear Information System (INIS)

    Dodge, C.T.; Rong, J.; Dodge, C.W.

    2014-01-01

    Purpose: To determine how filtered back-projection (FBP), adaptive statistical (ASiR), and model based (MBIR) iterative reconstruction algorithms affect the measured modulation transfer functions (MTFs) of variable-contrast targets over a wide range of clinically applicable dose levels. Methods: The Catphan 600 CTP401 module, surrounded by an oval, fat-equivalent ring to mimic patient size/shape, was scanned on a GE HD750 CT scanner at 1, 2, 3, 6, 12 and 24 mGy CTDIvol levels with typical patient scan parameters: 120kVp, 0.8s, 40mm beam width, large SFOV, 2.5mm thickness, 0.984 pitch. The images were reconstructed using GE's Standard kernel with FBP; 20%, 40% and 70% ASiR; and MBIR. A task-based MTF (MTFtask) was computed for six cylindrical targets: 2 low-contrast (Polystyrene, LDPE), 2 medium-contrast (Delrin, PMP), and 2 high-contrast (Teflon, air). MTFtask was used to compare the performance of reconstruction algorithms with decreasing CTDIvol from 24mGy, which is currently used in the clinic. Results: For the air target and 75% dose savings (6 mGy), MBIR MTFtask at 5 lp/cm measured 0.24, compared to 0.20 for 70% ASiR and 0.11 for FBP. Overall, for both high-contrast targets, MBIR MTFtask improved with increasing CTDIvol and consistently outperformed ASiR and FBP near the system's Nyquist frequency. Conversely, for Polystyrene at 6 mGy, MBIR (0.10) and 70% ASiR (0.07) MTFtask was lower than for FBP (0.18). For medium and low-contrast targets, FBP remains the best overall algorithm for improved resolution at low CTDIvol (1–6 mGy) levels, whereas MBIR is comparable at higher dose levels (12–24 mGy). Conclusion: MBIR improved the MTF of small, high-contrast targets compared to FBP and ASiR at doses of 50%–12.5% of those currently used in the clinic. However, for imaging low- and mediumcontrast targets, FBP performed the best across all dose levels. For assessing MTF from different reconstruction algorithms, task-based MTF measurements are necessary

  11. Image evaluation and exposure dose with the application of tube voltage and adaptive statistical iterative reconstruction of low dose computed tomography

    International Nuclear Information System (INIS)

    Moon, Tae Joon; Kim, Ki Jeong; Lee, Hye Nam

    2017-01-01

    The study has attempted to evaluate and compare the image evaluation and exposure dose by respectively applying filter back projection (FBP), the existing test method, and adaptive statistical iterative reconstruction (ASIR) with different values of tube voltage during the low dose computed tomography (LDCT). With the image reconstruction method as basis, chest phantom was utilized with the FBP and ASIR set at 10%, 20% respectively, and the change of tube voltage (100 kVp, 120 kVp). For image evaluation, back ground noise, signal-noise ratio (SNR) and contrast-noise ratio (CNR) were measured, and, for dose assessment, CTDIvol and DLP were measured respectively. In terms of image evaluation, there was significant difference in ascending aorta (AA) SNR and inpraspinatus muscle (IM) SNR with the different amount of tube voltage (p < 0.05). In terms of CTDIvol, the measured values with the same tube voltage of 120 kVp were 2.6 mGy with no-ASIR and 2.17 mGy with 20%-ASIR respectively, decreased by 0.43 mGy, and the values with 100 kVp were 1.61 mGy with no-ASIR and 1.34 mGy with 20%-ASIR, decreased by 0.27 mGy. In terms of DLP, the measured values with 120 kVp were 103.21 mGy‧cm with no-ASIR and 85.94 mGy‧cm with 20%-ASIR, decreased by 17.27mGy‧cm (about 16.7%), and the values with 100 kVp were 63.84 mGy‧cm with no-ASIR and 53.25 mGy‧cm with 20%-ASIR, a decrease by 10.62 mGy‧cm ( about 16.7%). At lower tube voltage, the rate of dose significantly decreased, but the negative effects on image evaluation was shown due to the increase of noise

  12. TU-D-209-01: Dosimetry of Diagnostic Work Up Mammography

    International Nuclear Information System (INIS)

    Jallow, N; Sechopoulos, I

    2016-01-01

    Purpose: To investigate patient average glandular dose (AGD) characteristics of diagnostic mammography. Methods: The techniques used to image 14420 patients who received diagnostic work up mammography from October 2008 to December 2014 at one academic hospital were retrospectively collected. The most common diagnostic views and the techniques used for each according to compressed breast thickness were determined. For all techniques, 1st half value layer and air kerma output per tube current-exposure time product were measured; then the incident air kerma for each acquisition was calculated. The values for normalized glandular dose (DgN) were obtained with a validated Monte Carlo simulation of mammographic acquisition. The mono-energetic DgN results were combined according to relative fluence using the TASMICS model to obtain DgN coefficients for each spectrum. The spectral DgN and calculated incident air kerma were used to estimate AGD of patients with breast thickness ranging from 2 to 8 cm. Results: The most common views utilized during diagnostic mammography were magnification craniocaudal (24%), magnification mediolateral (19%), spot craniocaudal (28%), and spot mediolateral oblique (24%). The AGD increased with increasing breast thickness for both the magnification and spot views. The AGD for a 5.5 cm thick breast was approximately 6.8 mGy and 2.2 mGy for the magnification and spot views, respectively. The AGD ranged from 3.6 mGy to 6.8 mGy for the magnification views and from 1.0 mGy to 3.1 mGy for spot views. The difference in AGD between the two magnification views or the two spot views was not significant. Conclusion: These results provide information on breast dose to which screening recalled women are exposed to. In addition to understanding the dose used for common clinical imaging tests, this data could be used when comparing use of mammography for diagnostic workup to other potential modalities, such as breast tomosynthesis and breast CT.

  13. Optimization of pediatric examinations in a multislice helical CT

    International Nuclear Information System (INIS)

    Ombada, T. H. A.

    2010-12-01

    Radiological protection of pediatric patients undergoing medical imaging procedures involving ionizing radiation has always received special attention. This is due to the fact that children have higher radiation sensitivity and increased likelihood for radiation-induced cancer manifesting in many more years of their life than adults. In computed tomography (CT), such attention is more important because of the potential of relatively higher radiation doses during these procedures. Such high doses are possible with technological developments where volume scanning using faster multi-slice CT systems is now preferred to conventional CT equipment. The task of this study is to assess the optimization of paediatric doses in multi-slice CT examinations. It was carried out in Alrebat University Hospital for 31 pediatric patients, 43 examinations (27 head examination and 16 body (chest, abdomen and pelvis) examinations). Data were collected for scan parameters (kV, m As, pitch, scan length, number of slices and slice thickness) and doses displayed in monitor (CTDI v ol and DLP) for head examinations and body (chest, abdomen and pelvis) examinations. For head CT, displayed CTDI v ol ranged from 1.56 to 69.12 mGy, calculated value from 2.10 to 70.93 mGy. Displayed DLP ranged from 53 to 1817 mGy.cm, calculated from 95.30 to 1532.16 mGy. cm. For body examination, the range of displayed CTDI from 1.63 to 3.92 mGy, calculated value from 2.22 to 5.34 mGy. Displayed DLP ranged from 34 to 194 mGy.cm, for calculated from 45.89 to 161.98 mGy. cm. The calculated values are in agreement with reference study dose values although there are some high values in this study for some examinations, this variation or difference may attribute to variation in pediatric ages (9 days- 15 years), scan length and m As values. There is variation between calculated and displayed values. more optimization for CT doses is needed. (Author)

  14. Radiation dose levels in pediatric chest CT: experience in 499 children evaluated with dual-source single-energy CT

    International Nuclear Information System (INIS)

    Martine, Remy-Jardin; Colas, Lucie; Jean-Baptiste, Faivre; Remy, Jacques; Santangelo, Teresa; Duhamel, Alain; Deschildre, Antoine

    2017-01-01

    The availability of dual-source technology has introduced the possibility of scanning children at lower kVp with a high-pitch mode, combining high-speed data acquisition and high temporal resolution. To establish the radiation dose levels of dual-source, single-energy chest CT examinations in children. We retrospectively recorded the dose-length product (DLP) of 499 consecutive examinations obtained in children <50 kg, divided into five weight groups: group 1 (<10 kg, n = 129); group 2 (10-20 kg, n = 176); group 3 (20-30 kg, n = 99), group 4 (30-40 kg, n = 58) and group 5 (40-49 kg, n = 37). All CT examinations were performed with high temporal resolution (75 ms), a high-pitch mode and a weight-adapted selection of the milliamperage. CT examinations were obtained at 80 kVp with a milliamperage ranging between 40 mAs and 90 mAs, and a pitch of 2.0 (n = 162; 32.5%) or 3.0 (n = 337; 67.5%). The mean duration of data acquisition was 522.8 ± 192.0 ms (interquartile range 390 to 610; median 490). In the study population, the mean CT dose index volume (CTDIvol 32 ) was 0.83 mGy (standard deviation [SD] 0.20 mGy; interquartile range 0.72 to 0.94; median 0.78); the mean DLP 32 was 21.4 mGy.cm (SD 9.1 mGy.cm; interquartile range 15 to 25; median 19.0); and the mean size-specific dose estimate (SSDE) was 1.7 mGy (SD 0.4 mGy; interquartile range 1.5 to 1.9; median 1.7). The DLP 32 , CTDI vol32 and SSDE were found to be statistically significant in the five weight categories (P < 0.0001). This study establishes the radiation dose levels for dual-source, single-kVp chest CT from a single center. In the five weight categories, the median values varied 15-37 mGy.cm for the DLP 32 , 0.78-1.25 mGy for the CTDI vol32 and 1.6-2.1 mGy for the SSDE. (orig.)

  15. Optimization of pediatric examinations in a multislice helical CT

    Energy Technology Data Exchange (ETDEWEB)

    Ombada, T H. A. [Atomic Energy Council, Sudan Academy of Sciences (SAS), Khartoum (Sudan)

    2010-12-15

    Radiological protection of pediatric patients undergoing medical imaging procedures involving ionizing radiation has always received special attention. This is due to the fact that children have higher radiation sensitivity and increased likelihood for radiation-induced cancer manifesting in many more years of their life than adults. In computed tomography (CT), such attention is more important because of the potential of relatively higher radiation doses during these procedures. Such high doses are possible with technological developments where volume scanning using faster multi-slice CT systems is now preferred to conventional CT equipment. The task of this study is to assess the optimization of paediatric doses in multi-slice CT examinations. It was carried out in Alrebat University Hospital for 31 pediatric patients, 43 examinations (27 head examination and 16 body (chest, abdomen and pelvis) examinations). Data were collected for scan parameters (kV, m As, pitch, scan length, number of slices and slice thickness) and doses displayed in monitor (CTDI{sub v}ol and DLP) for head examinations and body (chest, abdomen and pelvis) examinations. For head CT, displayed CTDI{sub v}ol ranged from 1.56 to 69.12 mGy, calculated value from 2.10 to 70.93 mGy. Displayed DLP ranged from 53 to 1817 mGy.cm, calculated from 95.30 to 1532.16 mGy. cm. For body examination, the range of displayed CTDI from 1.63 to 3.92 mGy, calculated value from 2.22 to 5.34 mGy. Displayed DLP ranged from 34 to 194 mGy.cm, for calculated from 45.89 to 161.98 mGy. cm. The calculated values are in agreement with reference study dose values although there are some high values in this study for some examinations, this variation or difference may attribute to variation in pediatric ages (9 days- 15 years), scan length and m As values. There is variation between calculated and displayed values. more optimization for CT doses is needed. (Author)

  16. Application of chemical dosemeters during the irradiation of agricultural products

    Energy Technology Data Exchange (ETDEWEB)

    Kovacs, A; Stenger, V; Foeldiak, G [Magyar Tudomanyos Akademia, Budapest. Izotopintezete

    1983-09-01

    The joint recommedation by the FAO, WHO and IAEA in 1981 proposed the unrestricted permission of food irradiation under the dose value of 10 kGy (1 Mrd). The chemical dosemeters presented in the paper cover the dose range of 30 Gy to 1 MGy for use to food irradiation safety measurements. The Fricke dosemeter was used in the 50-400 Gy range at radappertization operations of onion, poppy and potato. The alcoholic chlorobenzene dosemeter with oscillometric analysis was applied successfully at low (0.4-4 kGy) ranges, primarily for irradiation dose monitoring of fruits, vegetables, refrigerated poultry etc. The conductometry could be used for dosimetry in the range of 60 Gy to 1 MGy.

  17. Antenatal exposure following the Chernobyl accident: neuropsychiatric aspects

    International Nuclear Information System (INIS)

    Igumnov, S.A.; Drozdovitch, V.V.

    2004-01-01

    Ten years follow-up investigation of intellectual development of 250 persons from Belarus exposed in utero following the Chernobyl accident and a control group of 250 persons from non- and slightly contaminated regions has been conducted. Neuropsychiatry and psychological examinations were performed among persons of both groups at the age of 6-7, 0-12, and 15-16 years. Mean antenatal external dose among persons of exposed group is 10 ± 13 mGy, maximal dose - 91 mGy. No statistically significant correlation was found in exposed group between individual thyroid dose as well as individual antenatal external dose and IQ at the age of 6-7 years, 10-12 years, and 15-16 years

  18. Enhancement of certain agro-cellulosic wastes through radiation processing for livestock feed

    International Nuclear Information System (INIS)

    Farag, D.M.H.; Zakaria, S.

    1999-01-01

    A study was undertaken with air-dried peanut hulls, sugarcane bagasse, corn stalks, concobs, banana leaves, wheat straw and broad bean straw to determine the effect of radiation treatment up to 3 MGY on their chemical composition and the effect of enzymatic hydrolysis on treated wastes. The effect of gamma irradiation on crude protein, fat and ash of these wastes was negligible. While radiation treatment reduced the content of crude fiber in all these wastes with corresponding increases in dry matter digestibility in vitro, as a function of radiation dose. When peanut hulls, sugarcane bagasse and wheat straw were exposed to gamma rays at 0, 1, 2 and 3 MGy a linear reduction in fiber components (neutral detergent fiber, acid detergent fiber, and lignin), increased in glucose yield enzymatic hydrolysis and dry matter digestibility were observed for peanut hulls, sugarcane bagasse and wheat straw. The findings confirm that irradiation of fibrous vegetable materials could convert them into a valuable feed supplement

  19. Degradation of polyimide under irradiation with swift heavy ions

    International Nuclear Information System (INIS)

    Severin, D.; Ensinger, W.; Neumann, R.; Trautmann, C.; Walter, G.; Alig, I.; Dudkin, S.

    2005-01-01

    Stacks of polyimide foils were irradiated with different swift heavy ions (Ti, Mo, Au) of 11.1 MeV/nucleon energy and fluences between 1 x 10 10 and 2 x 10 12 ions/cm 2 . Beam-induced degradation of the imide group was analyzed by Fourier-transform infrared spectroscopy studying the absorption band at 725 cm -1 as a function of dose. In the UV-Vis spectral range, the absorption edge is shifted to larger wavelengths indicating carbonization. Such modifications are linked to the deposition of a critical dose of 2.7 MGy (Ti) and 1 MGy (Mo, Au). In addition, irradiation-induced changes of the electrical conductivity were studied by means of dielectric spectroscopy

  20. Estimation of MSAD values in computed tomography scans using radiochromic films

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Bruno Beraldo; Teogenes Augusto da, E-mail: bbo@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Mourao, Arnaldo Prata [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET-MG), Belo Horizonte, MG (Brazil)

    2013-03-15

    Objective: To evaluate the feasibility of using radiochromic films as an alternative dosimeter to estimate the multiple scan average dose on the basis on kerma profiles. Materials and Methods: The radiochromic films were distributed in cylinders positioned in the center and in four peripheral bores of a standard abdominal phantom utilized for computed tomography dosimetry. Results: Values for multiple scan average dose values corresponded to 13.6 {+-} 0.7, 13.5 {+-} 0.7 and 18.7 {+-} 1.0 mGy for pitch of 0.75, 1.00 and 1.50, respectively. Conclusion: In spite of results showing lower values than the reference level for radiodiagnosis (25 mGy) established by the Brazilian regulations for abdominal studies, it is suggested that there is room to optimize procedures and review the reference level for radiodiagnosis in Brazil. (author)

  1. Reduction of radiation dose by using digital luminescence radiography compared to conventional screen film system with grid cassette; Reduktion der Strahlendosis mittels Speicherfolienradiographie im Vergleich zum konventionellen Film-Folien-System mit Rasterkassette am Schaedelphantom

    Energy Technology Data Exchange (ETDEWEB)

    Heyne, J.P.; Merbold, H.; Neumann, R.; Freesmeyer, M.; Jonetz-Mentzel, L.; Kaiser, W.A. [Friedrich-Schiller-Univ. Jena, Inst. fuer Diagnostische und Interventionelle Radiologie (Germany); Sehner, J. [AGFA-Deutschland, Vertriebsgesellschaft (Germany)

    1999-07-01

    Purpose: How much can the radiation dose be reduced for skull radiography by using digital luminescence radiography (DLR) compared to a conventional screen film system with a grid cassette? Methods and Materials: A skull phantom (3M) was X-rayed in anterior-posterior orientation using both a conventional screen film system with grid cassette and DLR (ADC-70, Agfa). The tube current time product (mAs) was diminished gradually while keeping the voltage constant. The surface entrance dose was measured by a sensor of Dosimax (Wellhoefer). Five investigators evaluated the images by characteristic and critical features, spatial resolution and contrast. Results: The surface entrance dose at 73 kV/22 mAs was 0,432 mGy in conventional screen film system and 0,435 mGy in DLR. The images could be evaluated very well down to an average dose of 71% (0,308 mGy; SD 0,050); sufficient images were obtained down to an average dose of 31% (0,136 mGy; SD 0,065). The resolution of the line pairs were reduced down to a 2 levels depending on the investigator. Contrast was assessed as being very good to sufficient. The acceptance of the postprocessed images (MUSICA-software) was individually different and resultde in an improvement of the assessment of bone structures an contrast in higher dose ranges only. Conclusion: For the sufficient assessment of a possible fracture/of paranasal sinuses/of measurement the skull the dose can be reduced to at least 56% (31%; SD 14,9%)/40% (27%; SD 9,3%)/18% (14%; SD 4,4%). Digital radiography allows question-referred exposure parameters with clearly reduced dose, so e.g. for fracture exclusion 73 kV/12,5 mAs and to skull measurement 73 kV/4 mAs. (orig.) [Deutsch] Ziel: Wie weit kann unter Einsatz der rasterlosen Speicherfolienradiographie bei einer Schaedelaufnahme die Strahlendosis im Vergleich zum Film-Folien-System (FFS) mit Rasterkassette (RK) fragestellungsbezogen gesenkt werden? Material und Methode: Ein Schaedelphantom (3M) wurde konventionell

  2. Effect of low dose radiation on Th1 and Th2 of thymocytes and splenocytes in mice

    International Nuclear Information System (INIS)

    Bai Ou; Liu Shuzheng; Mu Ying

    1998-01-01

    Objective: To elucidate the possible mechanism of activation of helper T cells after low dose radiation (LDR) exposure, the influence of whole-body irradiation (WBI) with 75 mGy X-rays on Th1 and Th2 was studied. Methods: Mice were irradiated at a dose rate of 12.5 mGy/min, and IFN-γ and IL-6 mRNA levels of the myocytes and splenocytes were analyzed by dot blot and Northern blot hybridization. Results: It was found that IFN-γ and IL-6 mRNA significantly increased after WBI with 75 mGy X-rays. Conclusion: The gene induction of cytokine profile after LDR indicates that activation of both Th1 and Th2 subtypes may be involved in the stimulation of immune functions by LDR

  3. Dosimetry and bone densitometry. Comparison between lunar 1Q and Hologic 4500A

    International Nuclear Information System (INIS)

    Philippon, B.; Duboeuf, F.; Itti, R.

    2002-01-01

    Patient dosimetry related to two bone densitometer units from different manufacturers (LUNAR IQ and HOLOGIC 4500A) were evaluated using the parallel beam technique and thermoluminescence from Ca (SO4)/Dy. The radiation dose measured for a phantom of 18 cm in thickness was 0,11 mGy (+/- 0,004) at a maximum current of 3 mA for the LUNAR IQ unit in the high-resolution mode. The radiation dose is 0,28 mGy (+/- 0,011) for the HOLOGIC 4500A unit used at 2,5 mA in the high resolution-mode. These results obtained by thermoluminescence of the Ca (SO4)/Dy are in favor of the LUNAR IQ unit. However, dosimetry must be weighted against image quality. (author)

  4. Hereditary effects of low and chronic radiation exposure: a case-control study of mental retardation and cleft lip/palate in the monazite bearing coastal areas of Southern Kerala

    International Nuclear Information System (INIS)

    Koya, P.K.M.; Cheriyan, V.D.; Chougaonkar, M.P.; Mayya, Y.S.; Jojo, P.J.; Predeep, P.; Seshadri, M.

    2010-01-01

    The high level natural radiation (HLNR) areas of Kerala in the south west coast of Kerala is suitable for direct human studies to assess the genetic and teratogenic effect of low and chronic radiation exposures. The radiation level in the region (about 55 km long and 0.5 km wide belt) range from ≤1.0 mGy to 45.0 mGy per year and is due to natural deposit of monazite sand containing Thorium (8-10%), Uranium (0.3%) and corresponding decay products. A population based case-control study was carried out in the area to assess the role, if any, of HLNR as a causative factor in the etiology of two relatively frequent and easily identifiable congenital malformations, viz., mental retardation (MR) and cleft lip/palate (CLP). Findings from the study are discussed in this paper

  5. Losses of runaway electrons in MHD-active plasmas of the COMPASS tokamak

    Science.gov (United States)

    Ficker, O.; Mlynar, J.; Vlainic, M.; Cerovsky, J.; Urban, J.; Vondracek, P.; Weinzettl, V.; Macusova, E.; Decker, J.; Gospodarczyk, M.; Martin, P.; Nardon, E.; Papp, G.; Plyusnin, V. V.; Reux, C.; Saint-Laurent, F.; Sommariva, C.; Cavalier, J.; Havlicek, J.; Havranek, A.; Hronova, O.; Imrisek, M.; Markovic, T.; Varju, J.; Paprok, R.; Panek, R.; Hron, M.; The COMPASS Team

    2017-07-01

    The significant role of magnetic perturbations in mitigation and losses of runaway electrons (REs) was documented in dedicated experimental studies of RE at the COMPASS tokamak. REs in COMPASS are produced both in low density quiescent discharges and in disruptions triggered by massive gas injection (MGI). The role of the RE seed produced in the beginning of the discharge on the subsequent RE population proved significant. Modulation of the RE losses by MHD instabilities was observed at several characteristic frequencies, as well as by magnetic field oscillations related to power supplies. Magnetic islands seem to suppress the losses as the HXR signal is low and coherent with the island rotation frequency. Moreover, periods of increased losses of REs observed in the current quench (CQ) and early RE beam plateau phase of the MGI disruptions seem to be linked to the bursts of magnetic perturbation, and to the observation of filaments in the fast visible camera images.

  6. The effect of electron irradiation on the structure and iron speciation in sodium aluminum (iron) phosphate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Stefanovsky, S.V., E-mail: serge.stefanovsky@yandex.ru [Frumkin Institute of Physical Chemistry and Electrochemistry RAS (Russian Federation); Presniakov, I.A.; Sobolev, A.V.; Glazkova, I.S. [Lomonosov Moscow State University, Department of Chemistry (Russian Federation); Kadyko, M.I.; Stefanovsky, O.I. [Frumkin Institute of Physical Chemistry and Electrochemistry RAS (Russian Federation)

    2016-08-01

    The effect of 8 MeV electron irradiation on the structure of glasses in the series 40 Na{sub 2}O, (20-x) Al{sub 2}O{sub 3}, x Fe{sub 2}O{sub 3}, 40 P{sub 2}O{sub 5} (mol.%) and on the iron speciation in these samples was studied by FTIR and Mössbauer spectroscopic techniques. Irradiation up to a dose of 1.0 MGy has no appreciable effects on the character of the bonds within anionic motif of the glass network. Electron irradiation increases the fraction of aluminum in octahedral coordination. Iron in both unirradiated and irradiated glasses is present mainly as Fe(III) (60–75% of the total amount) in the glasses and partly as Fe(II) and the ratio of two forms remains constant up to a dose of 1.0 MGy.

  7. Uncertainties in low γ-dose determinations by means of ESR using the biomaterial modern coral reef

    International Nuclear Information System (INIS)

    Hassan, Gamal M.; Sharaf, M.A.

    2006-01-01

    The ESR spectrum of unirradiated modern aragonite coral (CaCO 3 ) material from the Red Sea (Hurgada area) is characterized by four signals with spectroscopic splitting factors of g=2.0056, 2.0030, 2.0006 and 1.997. The most intensive and stable line in this spectrum is attributed to CO 2 - radicals at g=2.0006+/-0.0005. The dose response from 50mGy to 20Gy, energy dependence and effective atomic number are calculated so as to investigate coral as a dosimeter material in the clinical dose range. The lower experimental γ-dose limit was found to be 50mGy with signal-to-noise (S/N) ratio of 15. The combined and expanded uncertainties accompanying these measurements are 1.72% and 3.44%, respectively

  8. Medical-biological aspects of radiation effects in Daphnia magna

    International Nuclear Information System (INIS)

    Sarapultseva, E; Ustenko, K; Uskalova, D; Savina, N

    2017-01-01

    We have shown that γ-irradiation at doses of 100 and 1000 mGy significantly compromised fecundity and reproductive success of the directly exposed D. magna . These effects were also observed among the non-exposed first-generation progeny of irradiated parents, thus implying the manifestation of transgenerational effects in Daphnia . We have also shown that compromised viability of irradiated D. magna can be attributed cytotoxic effects of irradiation. It would therefore appear that the compromised viability may be attributed to the cytotoxic effects resulted from epigenetic changes affecting some metabolic pathways involved in detoxification of free-radicals. Additionally we have analyzed more distant progeny of irradiated at doses of 10, 100 and 1000 mGy Daphnia . Our data demonstrated that multicellular crustacean D. magna represent a very useful experimental model for analyse of long-term effects of ionising radiation at the organismal level. (paper)

  9. Electron beam irradiation pretreatment and enzymatic saccharification of used newsprint and paper mill wastes

    International Nuclear Information System (INIS)

    Khan, A.W.; Labrie, J.-P.; McKeown, Joseph

    1987-01-01

    Electron beam pretreatment of used newsprint, pulp, as well as pulp recovered from clarifier sludge and paper mill sludge, caused the dissociation of cellulose from lignin, and rendered them suitable for enzymatic hydrolysis. A maximum dose of 1 MGy for newsprint and 1.5-2.0 MGy for pulp and paper mill sludge was required to render cellulose present in them in a form which, could be enzymatically saccharified to 90% of completion. Saccharification approaching the theoretical yield was obtained in 2 days with a cellulolytic enzyme system obtained from Trichoderma reesei. As a result of irradiation, water soluble lignin breakdown products, NaOH- soluble lignin, free cellobiose, glucose, mannose, xylose and their polymers, and acetic acid were produced from these materials. (author)

  10. Electron beam irradiation on cation exchanger used for strontium recovery

    International Nuclear Information System (INIS)

    Watanabe, Sou; Nakamura, Masahiro; Nomura, Kazunori; Nakajima, Yasuo; Okamoto, Yoshihiro

    2014-01-01

    Titanate is promising material for radioactive Sr recovery from liquid waste generated in the nuclear facilities. "9"0Sr is one of the most important nuclides in order to release the liquid waste into the environment due to its strong beta-ray decay energy. Although the titanate is applied to radioactive Sr decontamination facility, their resistance to irradiations from radioactive elements adsorbed is not widely investigated so far. In this study, durability of a hydrous titanic acid ion exchanger against beta-ray irradiation were evaluated through electron beam irradiation, elution behaviour of Sr after the irradiation and local structural analysis of the titanate. 1.4 MGy irradiation led to 1% of Sr elution, and the elution could be attributed to defects of O in the titanate induced by the irradiation. Chemical state of Ti of the titanate must be stable up to 2.7 MGy irradiation. (author)

  11. Radiation stability of some sealing materials used in nuclear power plants

    International Nuclear Information System (INIS)

    Lukac, P.; Foeldesova, M.; Dillinger, P.

    1987-01-01

    The radiation stability was investigated of sealing strips by Wonisch, Silhoffer and Dehtochema. Samples of the strips were irradiated with various single doses at a dose rate 5.27 kGy.h -1 . Changes in mechanical properties were studied by measuring tensile strength, ductility, compressibility and resistance against aqueous decontamination solutions. The results of the measurement were compared with values for non-irradiated materials and were expressed in percentage. The experiments showed that the materials were stable within the given region of absorbed radiation doses. The highest stability for a dose of 0.25 MGy was shown by the sealing strip Asfaretan by Dehtochema which in many properties compares well with foreign-made materials and in some respects is even better. Its compressibility is, however, worse. The experimental results have shown that polymerization processes (cross-linking) prevail at doses of up to 0.33 MGy and that material degradation prevails above this level. (author)

  12. Cytogenetic effect of low dose gamma-radiation in Hordeum vulgare seedlings: non-linear dose-effect relationship.

    Science.gov (United States)

    Geras'kin, Stanislav A; Oudalova, Alla A; Kim, Jin Kyu; Dikarev, Vladimir G; Dikareva, Nina S

    2007-03-01

    The induction of chromosome aberrations in Hordeum vulgare germinated seeds was studied after ionizing irradiation with doses in the range of 10-1,000 mGy. The relationship between the frequency of aberrant cells and the absorbed dose was found to be nonlinear. A dose-independent plateau in the dose range from about 50 to 500 mGy was observed, where the level of cytogenetic damage was significantly different from the spontaneous level. The comparison of the goodness of the experimental data fitting with mathematical models of different complexity, using the most common quantitative criteria, demonstrated the advantage of a piecewise linear model over linear and polynomial models in approximating the frequency of cytogenetical disturbances. The results of the study support the hypothesis of indirect mechanisms of mutagenesis induced by low doses. Fundamental and applied implications of these findings are discussed.

  13. Gamma-Ray Irradiation Effects on the Characteristics of New Material P Type 6H-SiC Ni-Schottky Diodes (Application For Nuclear Fuel Facilities)

    International Nuclear Information System (INIS)

    U-Sudjadi; T-Ohshima, N. Iwamoto; S-Hishiki; N-Iwamoto, K. Kawano

    2007-01-01

    Effects of gamma-ray irradiation on electrical characteristics of new material p type 6H-SiC Ni-Schottky diodes were investigated. Ni Schottky diodes fabricated on p type 6H-SiC epi-layer were irradiated with gamma-rays at RT. The electrical characteristics of the diodes were evaluated before and after irradiation. The value of the on-resistance does not change up to 1 MGy, and the value increases with increasing absorbed dose above 1 MGy. For n factor, no significant increase is observed below 500 kGy, however, the value increases above 500 kGy. Schottky Barrier Height (SBH) decreases with increasing absorbed dose. Leakage current tends to increase due to irradiation. (author)

  14. Unintentional exposure to radiation during pregnancy from nuclear medical diagnostic procedures

    International Nuclear Information System (INIS)

    Moka, D.

    2005-01-01

    The administration of radiopharmaceuticals during pregnancy is contraindicated due to a lack of vital indications. However, if prenatal exposure to radiation should occur in the framework of a nuclear medical diagnostic procedure then fortunately no longterm side-effects would normally be expected. Radiation damage in the preimplantation phase leads to early abortion. However, if the further course of pregnancy remains uncomplicated then no subsequent side-effects need be expected. On a conservative estimate, it would require doses exceeding 50 mGy to cause radiation damage within the uterus after the preimplantation phase. However, the standard radioactivities applied for diagnostic purposes in nuclear medicine, can be obtained with doses of less than 20 mGy. On the basis of current knowledge, therefore, there is no reason to terminate pregnancy on medical grounds after diagnostic exposure to radiopharmaceuticals. (orig.)

  15. EPR TOOTH DOSIMETRY OF SNTS AREA INHABITANTS.

    Science.gov (United States)

    Sholom, Sergey; Desrosiers, Marc; Bouville, André; Luckyanov, Nicholas; Chumak, Vadim; Simon, Steven L

    2007-07-01

    The determination of external dose to teeth of inhabitants of settlements near the Semipalatinsk Nuclear Test Site (SNTS) was conducted using the EPR dosimetry technique to assess radiation doses associated with exposure to radioactive fallout from the test site. In this study, tooth doses have been reconstructed for 103 persons with all studied teeth having been formed before the first nuclear test in 1949. Doses above those received from natural background radiation, termed "accident doses", were found to lie in the range from zero to approximately 2 Gy, with one exception, a dose for one person from Semipalatinsk city was approximately 9 Gy. The variability of reconstructed doses within each of the settlements demonstrated heterogeneity of the deposited fallout as well as variations in lifestyle. The village mean external gamma doses for residents of nine[ settlements were in the range from a few tens of mGy to approximately 100 mGy.

  16. EPR tooth dosimetry of SNTS area inhabitants

    Energy Technology Data Exchange (ETDEWEB)

    Sholom, Sergey [Scientific Center for Radiation Medicine, Melnikova str., 53, Kiev (Ukraine); Desrosiers, Marc [Ionizing Radiation Division, National Institute of Standards and Technology, Gaithersburg, MD (United States); Bouville, Andre; Luckyanov, Nicholas [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 6120 Executive Boulevard, Bethesda, MD (United States); Chumak, Vadim [Scientific Center for Radiation Medicine, Melnikova str., 53, Kiev (Ukraine); Simon, Steven L. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 6120 Executive Boulevard, Bethesda, MD (United States)], E-mail: ssimon@mail.nih.gov

    2007-07-15

    The determination of external dose to teeth of inhabitants of settlements near the Semipalatinsk Nuclear Test Site (SNTS) was conducted using the EPR dosimetry technique to assess radiation doses associated with exposure to radioactive fallout from the test site. In this study, tooth doses have been reconstructed for 103 persons with all studied teeth having been formed before the first nuclear test in 1949. Doses above those received from natural background radiation, termed 'accident doses', were found to lie in the range from zero to approximately 2 Gy, with one exception, a dose for one person from Semipalatinsk city was approximately 9 Gy. The variability of reconstructed doses within each of the settlements demonstrated heterogeneity of the deposited fallout as well as variations in lifestyle. The village mean external gamma doses for residents of nine settlements were in the range from a few tens of mGy to approximately 100 mGy.

  17. Comparative study of image quality and radiation dose between prospective and retrospective ECG gating technique in coronary artery imaging with 64-slice spiral CT

    International Nuclear Information System (INIS)

    Liu Jianxin; Liu Jian; Dou Yanbin; Wang Jichen; Sun Hongyue

    2009-01-01

    Objective: To compare the image quality and radiation dose between prospective ECG-trigering and retrospective ECG gating technique in coronary artery imaging. Methods: 33 patients suspected coronary artery disease were included in this study and divided into experimental group (prospective ECG-triggering coronary artery imaging, heart rate 0.05). The mean DLP of experimental group (234.4 mGy · cm) was DLP of control group (974.4 mGy · cm) 24.1%. The mean effective dose of prospective ECG gating coronary artery imaging was 3.2 mSv. Effective dose reduced 76.47 %. Conclusions: Prospective ECG gating coronary artery imaging can obtain the similar image quality compared with prospective ECG gating coronary artery imaging but the effective dose reduced 76.47 %. Prospective ECG gating coronary artery imaging has clinical value to peoples who are able to not accept high radiation dose and with low heart rate. (authors)

  18. Disruption Mitigation System Developments and Design for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Baylor, Larry R. [ORNL; Barbier, Charlotte N. [ORNL; Bull, Nora D. [ORNL; Combs, Stephen Kirk [ORNL; Fisher, Paul W. [ORNL; Kiss, Gabor [ITER Organization, Cadarache, France; Ericson, Milton Nance [ORNL; Wilgen, John B. [ORNL; Maruyama, So [ITER Organization, Cadarache, France; Meitner, Steven J. [ORNL; Lyttle, Mark S. [ORNL; Rasmussen, David A. [ORNL; Carmichael, Justin R. [ORNL; Smith, Stephen Fulton [ORNL

    2015-09-01

    A disruption mitigation system (DMS) is under design for ITER to inject sufficient material deeply into the plasma for rapid plasma thermal shutdown and collisional suppression of any resulting runaway electrons. Progress on the development and design of both a shattered pellet injector (SPI) that produces large solid cryogenic pellets to provide reliable deep penetration of material and a fast opening high flow rate gas valve for massive gas injection (MGI) is presented. Cryogenic pellets of deuterium and neon up to 25 mm in size have been formed and accelerated with a prototype injector and a full scale prototype MGI valve is now in testing. Implications of the design with respect to response time and reliability at the proposed injector locations on ITER are discussed.

  19. The applicability of the PTTL dose re-analysis method to the Harshaw LiF:Mg,Cu,P material

    International Nuclear Information System (INIS)

    Moscovitch, M.; Benevides, L.; Romanyukha, A.; Hull, F.; Duffy, M.; Voss, S.; Velbeck, K. J.; Nita, I.; Rotunda, J. E.

    2011-01-01

    The photo-transferred thermoluminescence (PTTL) technique is applied to the Harshaw LiF:Mg,Cu,P material. It is demonstrated that using 254-nm UV light, dose levels as low as 0.2 mGy can be re-estimated. The PTTL efficiency was found to be ∼6 % in the dose range of 0.2 mGy -1 Gy, and it appears to be dose-independent. This implies that a simple calibration factor could be applied to the PTTL data for the re-estimation of dose levels. It was demonstrated that with a proper choice of the TL readout parameters, and the UV-light irradiation conditions, dose levels that are relevant to personal or environmental dosimetry can be re-estimated. (authors)

  20. Dose evaluation in diagnostic for computerized tomography; Evaluacion de dosis en diagnostico por tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Flores, W.; Borges, J.C.; Mota, H. [Universidad Federal de Rio de Janeiro, PEN/COPPE/UFRJ. Caixa Postal 68509. 21945-970 Rio de Janeiro (Brazil)

    1998-12-31

    The patients which are subjected to computerized tomography tests are exposed to relatively high doses given as result doses on organs that are not matter to test. It was realized a dose levels raising in patients subjected to tests by T C, utilizing to measure this magnitude, TLD-100 thermoluminescent dosemeters which were put directly on the patient, in eye regions, thyroid, breast and navel; founding doses fluctuating between 29.10-49.39 mGy in organs examined and dose values between 0.21-29.10 mGy for organs that no matter to test. The applications of ionizing radiations in medicine do not have dose limits, but paying attention to the radiological protection optimization principle, it is recommended the use of clothes to anti-rays protection for zones not examined, getting with this to reduce the level doses as low as possible, without this to diminish the test quality. (Author)

  1. Dose evaluation in diagnostic for computerized tomography

    International Nuclear Information System (INIS)

    Flores, W.; Borges, J.C.; Mota, H.

    1998-01-01

    The patients which are subjected to computerized tomography tests are exposed to relatively high doses given as result doses on organs that are not matter to test. It was realized a dose levels raising in patients subjected to tests by T C, utilizing to measure this magnitude, TLD-100 thermoluminescent dosemeters which were put directly on the patient, in eye regions, thyroid, breast and navel; founding doses fluctuating between 29.10-49.39 mGy in organs examined and dose values between 0.21-29.10 mGy for organs that no matter to test. The applications of ionizing radiations in medicine do not have dose limits, but paying attention to the radiological protection optimization principle, it is recommended the use of clothes to anti-rays protection for zones not examined, getting with this to reduce the level doses as low as possible, without this to diminish the test quality. (Author)

  2. Dose reference levels in Spanish intraoral dental radiology: stabilisation of the incorporation of digital systems in dental clinical practices

    International Nuclear Information System (INIS)

    Alcaraz, M.; Velasco, F.; Olivares, A.; Velasco, E.; Canteras, M.

    2016-01-01

    A total of 34 044 official quality assurance reports in dental radiodiagnostic surgery from 16 regions of Spain, compiled from 2002 to 2014, were studied in order to determine the progress of diagnostic reference levels (DRLs) for obtaining diagnostic images under normal conditions for clinical practice in Spanish dental clinics. A DRL of 2.8 mGy was set in 2014, which represents a 41.7 % decrease compared with that of 2002 (4.8 mGy). Over the same time period, the mean dose fell by 55.2 %. However, over the last 3 y, the stabilisation of the mean dose administered to patients has been observed with only a 6.7 % reduction in DRLs, which corresponds to the stabilisation of dental radiodiagnostic surgery on replacing the use of radiographic film with digital imaging systems. (authors)

  3. Mitigation of upward and downward vertical displacement event heat loads with upper or lower massive gas injection in DIII-D

    Science.gov (United States)

    Hollmann, E. M.; Commaux, N.; Eidietis, N. W.; Lasnier, C. J.; Moyer, R. A.; Parks, P. B.; Shiraki, D.

    2015-10-01

    Intentionally triggered upward and downward vertical displacement events (VDEs) leading to disruptions were pre-emptively mitigated with neon massive gas injection (MGI) coming from either above or below the plasma. Global indicators of disruption mitigation effectiveness (conducted heat loads, radiated power, and vessel motion) do not show a clear improvement when mitigating with the gas jet located closer to the VDE impact area. A clear trend of improved mitigation is observed for earlier MGI timing relative to the VDE impact time. The plasma edge magnetic perturbation is seen to lock to a preferential phase during the VDE thermal quench, but this phase is not clearly matched by preliminary attempts to fit to the conducted heat load phase. Clear indications of plasma infra-red (IR) emission are observed both before and during the disruptions. This IR emission can affect calculation of disruption heat loads; here, the time decay of post-disruption IR signals is used to correct for this effect.

  4. Mitigation of upward and downward vertical displacement event heat loads with upper or lower massive gas injection in DIII-D

    International Nuclear Information System (INIS)

    Hollmann, E. M.; Moyer, R. A.; Commaux, N.; Shiraki, D.; Eidietis, N. W.; Parks, P. B.; Lasnier, C. J.

    2015-01-01

    Intentionally triggered upward and downward vertical displacement events (VDEs) leading to disruptions were pre-emptively mitigated with neon massive gas injection (MGI) coming from either above or below the plasma. Global indicators of disruption mitigation effectiveness (conducted heat loads, radiated power, and vessel motion) do not show a clear improvement when mitigating with the gas jet located closer to the VDE impact area. A clear trend of improved mitigation is observed for earlier MGI timing relative to the VDE impact time. The plasma edge magnetic perturbation is seen to lock to a preferential phase during the VDE thermal quench, but this phase is not clearly matched by preliminary attempts to fit to the conducted heat load phase. Clear indications of plasma infra-red (IR) emission are observed both before and during the disruptions. This IR emission can affect calculation of disruption heat loads; here, the time decay of post-disruption IR signals is used to correct for this effect

  5. Cytogenetic indices in blood lymphocytes of individuals from the staff working on new confinement constructing in Chornobyl NPP zone

    International Nuclear Information System (INIS)

    Bezdrobna, L.K.; Tarasenko, L.V.; Tsiganok, T.V.; Mel'nik, T.V.; Nosach, Yu.O.; Sushko, V.O.; Nechajev, S.Yu.; Shvajko, L.Yi.

    2014-01-01

    In contracting staff mean group frequency of aberrant lymphocytes, chromosome (dicentrics, acentrics, abnormal monocentrics) and chromatide type aberrations is significantly higher than such frequency in the comparison group. Three staff persons had individual frequency of specific markers of exposure - dicentric chromosomes with accompanying fragments significantly higher than their mean population level and the average frequency in the comparison group. It indicates the probability of their excess radiation when working in Chornobyl NPP local zone. Cells with two chromosome exchanges and one multiaberrant cell were registered in staff with the absence of such in control persons. The calculated estimated radiation doses of two staff persons were 87-123 mGy and and one person 210-240 mGy of acute exposure respectively. Calculated by frequency of dicentric chromosomes tentative 'biological' doses of three staff persons show a more significant radiation effect comparing to the data of physical dosimetry

  6. Reference dose levels for dental panoramic radiography in Gwangju (South Korea)

    International Nuclear Information System (INIS)

    Lee, J. S.; Kim, Y. H.; Yoon, S. J.; Kang, B. C.

    2010-01-01

    This study assessed the reference dose levels for dental panoramic radiography in Gwangju city (South Korea) based on the dose width product (DWP) and compared them with those already established elsewhere. A total of 44 panoramic dental radiographic sets (36 digital and 8 analogue panoramic sets) in 41 dental clinics in Gwangju city were chosen. The third quartile DWP was determined from 429 surface dose measurements of the adult surface dose in panoramic dental radiography. The third quartile DWP for panoramic radiography was 60.1 mGy mm. The proposed DWP reference levels of 60.1 mGy mm were less than or equal to those previously reported in other countries, such as Italy and UK, and acceptable for panoramic radiography in Gwangju (KR). (authors)

  7. Biophysical dosimetry using electron paramagnetic resonance in human tooth

    International Nuclear Information System (INIS)

    Khan, R.F.H.; Boreham, D.R.; Rink, W.J.

    2002-01-01

    Accidental dosimetry utilizing radiation induced paramagnetic species in biophysical tissues like teeth is a technique; that can measure the amount of radiation exposure to an individual. The major problem in implementing this technique at low doses is the presence of native organic signal, and various other artifacts produced as a result of sample processing. After a series of experimental trials, we developed an optimum set of rules, which uses high temperature ultrasonic treatment of enamel in KOH, multiple sample rotation during in-cavity measurement of natural and calibrated added irradiations, and dose construction using a backward extrapolation method. By using this we report the successful dose reconstruction in a few of our laboratory samples in 100 mGy range (76.29 ± 30.14) mGy with reasonably low uncertainty. Keywords: biophysical dosimetry, human tooth enamel, low dose measurements, accidental dosimetry (author)

  8. Report on results of seventeen years in consultations of radiation exposed pregnant women

    International Nuclear Information System (INIS)

    Bruening, L.; Arndt, D.; Laude, G.

    1992-01-01

    In a survey it will be given results of consultations of pregnant women exposed during the pregnancy in the period of 1976 to 1992 formerly in the National Board of Atomic Safety and Radiation Protection of the GDR and since 1990 in the Clinic-diagnostical Division of the Federal Health Office. The report includes dose estimations of the embryo and medical assessments of 430 pregnant women. The radiation exposure were mainly received by X-ray diagnostic (n = 406 cases) and the others by applications of radiation in nuclear medicine, research and vocational training (n = 24 cases). Results of dose and risk estimation were summarized in tables. Women having incurred fetal doses in excess of 100 mGy were recommended to interrupt pregnancy. A fetal dose above 100 mGy occured in 9 cases. The anatomico-pathological and embryological findings of the embryo or fetus showed only in one case a reference of teratogenic radiation damage. (orig.) [de

  9. Unintentional exposure to radiation during pregnancy from nuclear medical diagnostic procedures; Unabsichtliche Strahlenexposition in der Schwangerschaft durch nuklearmedizinische Diagnostik

    Energy Technology Data Exchange (ETDEWEB)

    Moka, D. [Gemeinschaftspraxis fuer Radiologie und Nuklearmedizin, Essen (Germany)

    2005-12-01

    The administration of radiopharmaceuticals during pregnancy is contraindicated due to a lack of vital indications. However, if prenatal exposure to radiation should occur in the framework of a nuclear medical diagnostic procedure then fortunately no longterm side-effects would normally be expected. Radiation damage in the preimplantation phase leads to early abortion. However, if the further course of pregnancy remains uncomplicated then no subsequent side-effects need be expected. On a conservative estimate, it would require doses exceeding 50 mGy to cause radiation damage within the uterus after the preimplantation phase. However, the standard radioactivities applied for diagnostic purposes in nuclear medicine, can be obtained with doses of less than 20 mGy. On the basis of current knowledge, therefore, there is no reason to terminate pregnancy on medical grounds after diagnostic exposure to radiopharmaceuticals. (orig.)

  10. Design and Radiation Assessment of Optoelectronic Transceiver Circuits for ITER

    CERN Document Server

    Leroux, P; Van Uffelen, M; Steyaert, M

    2008-01-01

    The presented work describes the design and characterization results of different electronic building blocks for a MGy gamma radiation tolerant optoelectronic transceiver aiming at ITER applications. The circuits are implemented using the 70GHz fT SiGe HBT in a 0.35μm BiCMOS technology. A VCSEL driver circuit has been designed and measured up to a TID of 1.6 MGy and up to a bit rate of 622Mbps. No significant degradation is seen in the eye opening of the output signal. On the receiver side, both a 1GHz, 3kΩ transimpedance and a 5GHz Cherry-Hooper amplifier with over 20dB voltage gain have been designed.

  11. Entrance doses during lateral lumbar spine and antero-posterior abdomen examinations: generator waveform dependence

    International Nuclear Information System (INIS)

    Morrison, G.D.; Underwood, A.C.

    1995-01-01

    In North Trent, UK, an entrance dose survey of lateral lumbar spine and antero-posterior (AP) abdomen examinations has been carried out in 17 radiology departments. The survey comprised 294 lateral lumbar spine and 322 AP abdomen entrance dose measurements. The mean entrance doses were found to be approximately half of the relevant national reference entrance dose levels of 30 mGy and 10 mGy, respectively. The effect of generator waveform on entrance dose was studied by separating the generators into two types: ''pulsating potential'' (PP) generators and ''constant potential'' (CP) generators for each examination. PP generators comprised 23% of the total number of examinations. The mean entrance dose and radiographic exposure factors from CP generators were found to be significantly lower than those from PP generators. The use of CP type generators, together with low attenuation components can significantly reduce patient entrance doses for these examinations. (author)

  12. Retrospective dosimetry: Preliminary use of the single aliquot regeneration (SAR) protocol for the measurement of quartz dose in young house bricks

    DEFF Research Database (Denmark)

    Banerjee, D.; Bøtter-Jensen, L.; Murray, A.S.

    1999-01-01

    with the expected values based on their known age and confirms the absolute accuracy of the SAR method. It is concluded that a similar to 18 mGy fallout dose component can be detected on a background of similar to 100 mGy; this detection limit is controlled by uncertainties in the natural dose rare measurement......In retrospective dosimetry, the total dose absorbed by some pre-existing dosemeters, such as house bricks or tiles, is used to derive the dose to the population arising from a nuclear accident. This paper uses the newly developed SAR protocol to determine the total dose in young house bricks from...... the vicinity of the Chernobyl reactor site and from Roskilde, Denmark. For these samples, it is shown that high precision (similar to 1%) on the mean estimates of total dose can be achieved with similar to 20 independent measurements. The SAR total dose estimates of two Danish house bricks agree...

  13. Multiwalled carbon nanotube destruction in the radiation damages to electron irradiation

    Directory of Open Access Journals (Sweden)

    T. M. Pinchuk-Rugal’

    2015-10-01

    Full Text Available Behavior of the X-ray diffraction and vibrational Raman spectra of multiwalled carbon nanotubes (MWCNT under high-energy electron irradiation (Ee = 1.8 MeV with large doses of absorption to 10 MGy were studied. With increasing dose uptake to 10.0 MGy, the interlayer correlation in the distribution of the individual graphene nanotubes nets not only is maintained, but is even improved. Defective bands D, D' and G band with increasing dose absorption have significant transformation, which show radiation damages of MWCNT. The destruction of nanotubes under electron irradiation is accompanied by increased regulation in the arrangement of individual nanotubes by interlayer cross-links involving interstitial atoms. The severity of degradation and cross-linking of MWCNT depends on the electron absorption dose.

  14. Use of the pre-dose technique for environmental dosimetry. [Thermoluminescence from fired bricks or tiles

    Energy Technology Data Exchange (ETDEWEB)

    Bailiff, I K [Durham Univ. (UK). TL Lab.; Haskell, E H [Utah Univ., Salt Lake City (USA). Radiobiology Div.

    1984-01-01

    The pre-dose effect associated with the 110/sup 0/C TL peak of quartz is the basis of a dating technique developed at the Oxford Laboratory, and now in use to date pottery and brick at the Durham Laboratory. Recently its use for the measurement of fallout gamma dose has been initiated at the University of Utah. Using quartz extracted from fired brick, the technique has been shown to be sufficiently sensitive to measure doses in the region of 10 mGy. The complexities of the technique encountered during dating in its upper range (approx. 5 Gy) are equally apparent in its lower range (10 mGy). With a common interest in the pre-dose technique, the research that is being performed to apply the technique through its full range in environmental dosimetry is discussed.

  15. Development of radiation resistant PEEK insulation cable

    International Nuclear Information System (INIS)

    Mio, Keigo; Ogiwara, Norio; Hikichi, Yusuke; Furukori, Hisayoshi; Arai, Hideyuki; Nishizawa, Daiji; Nishidono, Toshiro

    2009-04-01

    Material characterization and development has been carried out for cable insulation suitable for use in the J-PARC 3-GeV RCS radiation environment. In spite of its high cost, PEEK (polyether-ether-ketone) has emerged as the leading candidate satisfying requirements of being non-halogen based, highly incombustible and with radiation resistant at least 10 MGy, along with the usual mechanical characteristics such as good elongation at break, which are needed in a cable insulation. Gamma-ray irradiation tests have been done in order to study radiation resistance of PEEK cable. Further, mechanical, electrical and fire retardant characteristics of a complete cable such as would be used at the J-PARC RCS were investigated. As a result, PEEK cables were shown to be not degraded by radiation up to at least 10 MGy, and thus could be expected to operate stably under the 3-GeV RCS radiation environment. (author)

  16. Virtual non-contrast of liver from dual energy CT: a clinical application

    International Nuclear Information System (INIS)

    Qian Yu'e; Hu Hongjie; Zhang Qiaowei; Hu Peng; Shen Guohui

    2011-01-01

    Objective: To assess the virtual non-contrast liver CT from dual-energy CT for the clinical application. Methods: In total, 51 patients were included in the study, and all patients underwent multi-phase liver CT on a dual-source CT. The True non-contrast liver CT (TNCT) was performed in a single-energy acquisition mode, but the arterial and portovenous liver CT (VNCT) were performed in a dual- energy mode of 110 kV and 140 kV respectively. The virtual non-contrast CT images were derived from the arterial data using liver virtual non-contrast software. Between the true non-contrast CT and the virtual non- contrast CT, the image quality, mean CT HU values in the liver and muscle, signal to noise (SNR), the radiation dose of volume CT dose index (CTDIvol) and dose length product (DLP) in a single phase and total examination were compared with t test. Results: There was no significant difference in the detection of' liver lesions between TNCT and VNCT. The CT Hu values of muscle on both TNCT and VNCT images were almost equal. The CT HU values of liver on VNCT images were higher than that on TNCT images and the difference was significant [61.32±6.04 vs. (56.85±4.80) HU, t=-3.927, P<0.01]. There was also significant difference of SNR between TNCT (11.28±2.78) and VNCT (8.65±1.56) images (t=-5.590, P<0.01). The CTDIvol and DLP of single phase were (7.07±0.85) mGy and (155.11± 22.52) mGy · cm respectively in TNCT, and (7.05±0.87) mGy and (154.48±23.12) mGy · cm in VNCT. The total CTDIvol and DLP in VNCT were (14.35±1.66) mGy and (313.91±45.08) mGy · cm respectively, but in TNCT the total CTDIvol and DLP reached (21.43±2.46) mGy and (469.02± 66.22) mGy · cm. The difference of CTDIvol and DLP in single phase between TNCT and VNCT showed no significance, but the total CTDIvol and DLP were significantly different (t=16.168 and 13.132, P< 0.01). Conclusion: With the consequent reduction in radiation dose, the VNCT can replace TNCT as an imaging protocol in multi

  17. Powder ink coatings in nuclear medicine and nuclear technology

    International Nuclear Information System (INIS)

    Kunze, S.; Schlautek, H.

    1996-01-01

    Powder ink coatings are being used more and more frequently to protect the surfaces of movable objects of metal, such as machines, equipment, furniture, shelves, because this solvent-free coating technique, which produces almost no residues, helps to keep the environment clean. The white and grey baking coatings so far tested for decontaminability are presented in the article. Powder ink coatings of different shades and with different binders were tested for their ability to meet future standards. All systems under examination demonstrated excellent decontaminability before and after gamma exposure to 0.3 MGy. The same performance was obtained also after exposure to 3 MGy (ten times the level required for coatings in nuclear installations according to DIN 55991 Part 1), with the exception of one polyester metallic coating. After having been exposed to chemicals and decontamination solutions, all specimens showed only permissible discoloration. (orig.) [de

  18. Radiation Doses in Intravenous Urography And Potentials For Optimization

    International Nuclear Information System (INIS)

    Halato, M.A.; Badawi, A.; Gassom, G.A.; Barsham, M.A.; Ibrahim, A.F.; Suliman, I.I.; Sulieman, A.A.

    2011-01-01

    In this study radiation doses in IVU clinical examinations were measured in three public hospitals and a sample of 44 patients. In each room the machine output was measured for different peak tube voltages. Patient's data such as (age and weight) and exposure parameters (kVp) and mAs) were recorded. Entrance Surface Air Kerma (ESAK) for patients was determined by using the tube output and the patient exposure parameters. The ESAK ranged from 0.76 to 6.75 mGy. The cumulative ESAK ranged from 3.5 to 34.6 mGy. In conclusion, the obtained results are in agreement with the standard reference ESAK levels. The study showed that the cumulative ESAK can approach a level known to increase the probability of stochastic effect. Keywords: Patient dose, intravenous Urography, radiation protection

  19. Some dosimetric properties of the LiF:Mg,Ti evaluated by the automatic 6600 thermoluminescent reader

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Shachar, B; Weinstein, M; German, U [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev

    1996-12-01

    Some dosimetric properties of the new LiF:Mg,Ti TLD cards were checked, when evaluated by the new automatic 6600 TLD reader. The cards were calibrated to a dose of 1.0 mGy by five identical irradiations, and the TL-dose response was measured for a range of 75 - 1100 mGy. A very high accuracy was found for the three kind of chips measured (TLD-100, TLD-700 and TLD-600) and a low minimum measurable dose (MMD) was found, too. There is a good fit between the analytical evaluation and the theoretical calculation of the MMD. The results obtained are much better than those of the LiF:Mg,Ti cards evaluated by the older automatic 2271 reader used in the last two decades (authors).

  20. Study of needle morphometric indices in Scots pine in the remote period after the Chernobyl accident

    International Nuclear Information System (INIS)

    Makarenko, E.S.; Geras'kin, S.A.; Oudalova, A.A.

    2016-01-01

    Biological effects in Scots pine populations experiencing chronic radiation exposure at doses up to 130 mGy per year as a result of the Chernobyl accident were studied in 2011 and 2013, using needle indices as endpoints. No relationships between the length, the mass of needles and the asymmetry in weight of paired needles and radiation exposure were revealed. The frequency of necrotic needles increases with the level of radiation exposure; however, the significance of these effects in different years was different. The index of fluctuating asymmetry in needle length significantly increases at annual doses of 90 and 130 mGy and correlates with the absorbed dose as well as 137 Cs and 90 Sr radionuclide activities in soils and cones at the study sites. The findings obtained are consistent with an international recommendation to consider radiation exposure of 100 mGy.y -1 as a margin for biota safety in chronic irradiation. (authors)

  1. Actinide uptake onto zeolite-L and SAPO-34

    International Nuclear Information System (INIS)

    Amini, S.; Dyer, A.

    1994-01-01

    The characteristics of ion exchange of uranyl and americium, which are α-emitting radioactive nuclides, were examined by batch and column methods. SAPO-34 showed good selectivity for uranyl ion at pH 2-3.5, and distribution coefficients of Am 3+ and UO 2 2+ increased with equilibrium pH. γ irradiation (2 MGy) did not show any significant effect on the uptake of both of actinide ions onto L and SAPO-34. Higher doses of γ-irradiation (up to 10 MGy) created a change of equilibrium pH, and hence uptake, due to radiolysis of water and heat localization generated by γ-radiation and annealing processes. (author) 19 refs.; 15 figs.; 3 tabs

  2. Uncertainties in low {gamma}-dose determinations by means of ESR using the biomaterial modern coral reef

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Gamal M. [Department of Ionizing Radiation Metrology, National Institute for Standards (NIS), Tersa Street El-Haram El-Giza, P.O. Box 136 Giza, El-Giza (Egypt)]. E-mail: gamalhassan65@hotmail.com; Sharaf, M.A. [Department of Ionizing Radiation Metrology, National Institute for Standards (NIS), Tersa Street El-Haram El-Giza, P.O. Box 136 Giza, El-Giza (Egypt)

    2006-01-15

    The ESR spectrum of unirradiated modern aragonite coral (CaCO{sub 3}) material from the Red Sea (Hurgada area) is characterized by four signals with spectroscopic splitting factors of g=2.0056, 2.0030, 2.0006 and 1.997. The most intensive and stable line in this spectrum is attributed to CO{sub 2}{sup -} radicals at g=2.0006+/-0.0005. The dose response from 50mGy to 20Gy, energy dependence and effective atomic number are calculated so as to investigate coral as a dosimeter material in the clinical dose range. The lower experimental {gamma}-dose limit was found to be 50mGy with signal-to-noise (S/N) ratio of 15. The combined and expanded uncertainties accompanying these measurements are 1.72% and 3.44%, respectively.

  3. Effect of an electron beam on the subsequent pyrogenic distillation of lignin and cellulose

    International Nuclear Information System (INIS)

    Metreveli, P.K.; Metreveli, A.K.; Kholodkova, E.M.; Ponomarev, A.V.

    2014-01-01

    The irradiation notably influences responsiveness of cellulose and lignin to the subsequent pyrogenic distillation though both weight and the form of samples do not change almost at doses up to 3 MGy. Decreases in overpoint of lignin and cellulose irradiated at 2.2 MGy are ∼80°and ∼100°, respectively. Third of condensate from cellulose and almost half from lignin are distilled-off at lower temperatures. The thermally instable compounds convertible mainly to furans via subsequent heating are forming in cellulose. Distillation of the irradiated lignin gives less tar which, however, is richer by methoxy-phenols. In distilled-off water–organic fraction the content of soluble organic compounds is increased. - Highlights: • Irradiation facilitates subsequent dry distillation of cellulose and lignin. • Overpoints of irradiated samples are decreasing. • Furans and methoxy-phenols formation improves

  4. On the use of OSL of chip card modules with molding for retrospective and accident dosimetry

    International Nuclear Information System (INIS)

    Woda, Clemens; Fiedler, Irene; Spöttl, Thomas

    2012-01-01

    The potential of optically stimulated luminescence of wire-bond chip card modules with molded encapsulations for retrospective and accident dosimetry is investigated. Contact-based and contactless modules were studied, the latter finding potential use in electronic documents (e.g. electronic passports, electronic identity cards). Investigations were carried out on intact as well as chemically prepared modules, extracting the filler material. Contact-based modules are characterized according to zero dose signal, correlation between OSL and TL, dose response and long-term signal stability. For prepared modules, the minimum detectable dose immediately after irradiation is 3 mGy and between 20 and 200 mGy for contact-based and contactless modules, respectively. Dose recovery tests on contact-based modules indicate that the developed methodology yields results with sufficient accuracy for measurements promptly after irradiation, whereas a systematic underestimation is observed for longer delay times. The reasons for this behaviour are as yet not fully understood.

  5. A new calculation of the carcinogenic risk of obstetric X-raying

    International Nuclear Information System (INIS)

    Bithell, J.F.

    1988-01-01

    The association between obstetric X-raying and childhood cancer was first identified by the Oxford Survey of Childhood Cancers in 1956. The present re-analysis exploits the case-control matching of the study while incorporating the effects of important risk determinants, notably year of birth, trimester of exposure and number of films exposed. The decline in risk over time is closely mirrored by the estimated decline in dose per film and, by constraining these two relationships to be parallel, time-invariant estimates of the extra risk per mGy are obtained. For example, it is now estimated that irradiating 10 6 foetuses with 1 mGy of X-rays would, in the absence of other causes of death, yield 175 extra cases of cancer and leukaemia in the first 15 years of life. (author)

  6. Fabrication of SiC fibers by pyrolysis of polycarbosilane precursor fibers by γ-ray irradiation under the open air atmosphere

    International Nuclear Information System (INIS)

    Li Yang; Xu Yunshu; Xiong Liangping; Xia Xiulong; Xu Guangliang

    2007-01-01

    Polycarbosilane (PCS) precursor fibers were irradiated by γ-ray under the open air atmosphere, and then the fibers were converted to SiC ceramics fibers in inert atmosphere at high temperature. The chemical structure, microstructure and pyrolysis characteristic were studied. The results show that the oxygen in air reacts with some Si-H bonds in the PCS, bridge structures of Si-C-Si and Si-O-Si are formed in the irradiated products. The PCS fibers at the dose of 0.5 MGy are infusible in the process of sintering, at the dose of 3.0 MGy the gel content and ceramic yield are 75% and 85.17% ,respectively. The open air atmosphere can effectively reduce the curing dose. (authors)

  7. Estimation of eye absorbed doses in head & neck radiotherapy practices using thermoluminescent detectors

    Directory of Open Access Journals (Sweden)

    Gh Bagheri

    2011-09-01

    Full Text Available  Determination of eye absorbed dose during head & neck radiotherapy is essential to estimate the risk of cataract. Dose measurements were made in 20 head & neck cancer patients undergoing 60Co radiotherapy using LiF(MCP thermoluminescent dosimeters. Head & neck cancer radiotherapy was delivered by fields using SAD & SSD techniques. For each patient, 3 TLD chips were placed on each eye. Head & neck dose was about 700-6000 cGy in 8-28 equal fractions. The range of eye dose is estimated to be (3.49-639.1 mGy with a mean of maximum dose (98.114 mGy, which is about 3 % of head & neck dose. Maximum eye dose was observed for distsnces of about 3 cm from edge of the field to eye.

  8. The high dose response of silicon carbide MESFET; Reponse d'un transistor MESFET SiC irradie a de tres fortes doses cumulees

    Energy Technology Data Exchange (ETDEWEB)

    Brisset, C.; Picard, C.; Joffre, F. [CEA Saclay, Dept. d' Electronique et d' Instrumentation Nucleaire, LETI, 91 - Gif-sur-Yvette (France); Noblanc, O.; Brylinski, C. [Thomson-CSF Lab. Central de Recherches, 91 - Orsay (France)

    1999-07-01

    The performance of MESFET-SiC transistors submitted to {sup 60}Co gamma radiation has been studied. MESFETs irradiated in the passing mode present a satisfactorily behaviour till cumulated dose below 10 MGy(Si). The off-state operating mode is the most unfavourable, in this case a complete loss of functionality was observed, followed by a slow comeback to an almost normal functioning after several months of rest. (A.C.)

  9. Association of elevated radiation dose with mortality in patients with acute myocardial infarction undergoing percutaneous coronary intervention

    Energy Technology Data Exchange (ETDEWEB)

    Parikh, Puja B.; Prakash, Sheena; Tahir, Usman; Kort, Smadar; Gruberg, Luis; Jeremias, Allen, E-mail: allen.jeremias@stonybrook.edu

    2014-09-15

    Objectives: This study sought to identify clinical and procedural predictors of elevated radiation dose received by patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) and to determine if elevated radiation dose was predictive of mortality in this population. Background: Little data exist regarding the impact of excessive radiation burden on clinical outcomes in patients undergoing PCI. Methods: The study population included 1,039 patients who underwent PCI for an AMI between January 1, 2007 and December 31, 2008 at an academic tertiary care teaching hospital. Cumulative skin dose (measured in milligray [mGy]) was selected as a measurement of patient radiation burden. Clinical and procedural variables were analyzed in multiple logistic and linear regression models to determine predictors of higher skin dose, and its impact was evaluated on all-cause intermediate-term mortality at two years. Results: Median skin dose was 2120 mGy (IQR 1379–3190 mGy) in the overall population, of which 153 (20.8%) patients received an elevated skin dose (defined as a skin dose > 4,000 mGy). Independent predictors of elevated skin dose included male gender, obesity, multivessel intervention, and presentation with a non-ST-elevation MI (NSTEMI) versus an ST-elevation MI (STEMI). Increased skin dose was not predictive of intermediate-term mortality by multivariate analysis in the overall population or in either subgroup of STEMI and NSTEMI. Conclusions: In this contemporary observational study examining patients with AMI undergoing PCI, male gender, obesity, multivessel intervention, and presentation with a NSTEMI were associated with increased radiation exposure.

  10. Structured exploratory data analysis (SEDA) for determining mode of inheritance of quantitative traits. I. Simulation studies on the effect of background distributions.

    OpenAIRE

    Karlin, S; Williams, P T; Carmelli, D

    1981-01-01

    We examine through simulations the effectiveness of a new methodology to help distinguish among monogenic, multifactorial, and sporadic trait transmission from parents to offspring in nuclear family data sets. The major gene index (MGI), which compares the deviation of the offspring from the midparental value with a function of the individual deviations between parents and offspring, aids in the discrimination of multifactorial from sporadic and monogenic models. In contrast with other method...

  11. The study of mean glandular dose in mammography in Yazd and the factors affecting it

    International Nuclear Information System (INIS)

    Bouzarjomehri, F.; Mostaar, A.; Ghasemi, A.; Ehramposh, M. H.; Khosravi, H.

    2006-01-01

    The objective of this study was to determine the mean glandular dose resulting from mammography examinations in Yazd, southeastern Iran and to identify the factors affecting it. Patients and Methods: This survey was conducted during May to December 2005 to estimate the mean glandular dose for women undergoing mammography and to report the distribution of dose. compressed breast thickness, glandular tissue content, and mammography technique used. The clinical data were collected from 946 mammograms taken from 246 women who were referred to four mammography centers. The mammography instruments in these centers were four modern units with a molybdenum anode and either molybdenum or rhodium filter. The exposure conditions of each mammogram were recorded. The breast glandular content of each mammogram was estimated by a radiologist. The mean glandular dose was calculated based on measuring the normalized entrance skin dose in air. half value layer, kVp, mAs, breast thickness and glandular content. Half value layer, kVp and entrance skin dose were measured by a solid-state detector. The analytical method of Sobol et al. was used for calculation of mean glandular dose . Results: The mean±SD mean glandular dose per film was.2±0.6 mGy for cranio caudal and 1.63±O.9 mGy for mediolateral oblique views. The mean±SD mean glandular dose per woman was 5.5 3.1.mGy. A positive correlation was found between the beam Half value layer with mean glandular dose (r=O.38) and the breast thickness with mean glandular dose (r=O.5). Conclusion: The mean±SD mean glandular dose per film of 1.42±0.8 mGy in present study was lower than most of similar reports. However, the mean mean glandular dose per woman was higher than that in other studies

  12. Evaluation of a dedicated MDCT protocol using iterative image reconstruction after cervical spine trauma.

    Science.gov (United States)

    Geyer, L L; Körner, M; Hempel, R; Deak, Z; Mueck, F G; Linsenmaier, U; Reiser, M F; Wirth, S

    2013-07-01

    To evaluate radiation exposure for 64-row computed tomography (CT) of the cervical spine comparing two optimized protocols using filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR), respectively. Sixty-seven studies using FBP (scanner 1) were retrospectively compared with 80 studies using ASIR (scanner 2). The key scanning parameters were identical (120 kV dose modulation, 64 × 0.625 mm collimation, pitch 0.531:1). In protocol 2, the noise index (NI) was increased from 5 to 25, and ASIR and the high-definition (HD) mode were used. The scan length, CT dose index (CTDI), and dose-length product (DLP) were recorded. The image quality was analysed subjectively by using a three-point scale (0; 1; 2), and objectively by using a region of interest (ROI) analysis. Mann-Whitney U and Wilcoxon's test were used. In the FBP group, the mean CTDI was 21.43 mGy, mean scan length 186.3 mm, and mean DLP 441.15 mGy cm. In the ASIR group, the mean CTDI was 9.57 mGy, mean scan length 195.21 mm, and mean DLP 204.23 mGy cm. The differences were significant for CTDI and DLP (p 0.05). The estimated mean effective dose decreased from 2.38 mSv (FBP) to 1.10 mSv (ASIR). The radiation dose of 64-row MDCT can be reduced to a level comparable to plain radiography without loss of subjective image quality by implementation of ASIR in a dedicated cervical spine trauma protocol. These results might contribute to an improved relative risk-to-benefit ratio and support the justification of CT as a first-line imaging tool to evaluate cervical spine trauma. Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  13. [The reduction of the radiation dosage by means of storage phosphor-film radiography compared to a conventional film-screen system with a grid cassette on a skull phantom].

    Science.gov (United States)

    Heyne, J P; Merbold, H; Sehner, J; Neumann, R; Freesmeyer, M; Jonetz-Mentzel, L; Kaiser, W A

    1999-07-01

    How much can the radiation dose be reduced for skull radiography by using digital luminescence radiography (DLR) compared to a conventional screen film system with a grid cassette? A skull phantom (3M) was x-rayed in anterior-posterior orientation using both a conventional screen film system with grid cassette and DLR (ADC-70, Agfa). The tube current time product (mAs) was diminished gradually while keeping the voltage constant. The surface entrance dose was measured by a sensor of Dosimax (Wellhöfer). Five investigators evaluated the images by characteristic and critical features, spatial resolution and contrast. The surface entrance dose at 73 kV/22 mAs was 0.432 mGy in conventional screen film system and 0.435 mGy in DLR. The images could be evaluated very well down to an average dose of 71% (0.308 mGy; SD 0.050); sufficient images were obtained down to an average dose of 31% (0.136 mGy; SD 0.065). The resolution of the line pairs were reduced down to 2 levels depending on the investigator. Contrast was assessed as being very good to sufficient. The acceptance of the postprocessed images (MUSICA-software) was individually different and resulted in an improvement of the assessment of bone structures and contrast in higher dose ranges only. For the sufficient assessment of a possible fracture/of paranasal sinuses/of measurement of the skull the dose can be reduced to at least 56% (phi 31%; SD 14.9%)/40% (phi 27%; SD 9.3%)/18% (phi 14%; SD 4.4%). Digital radiography allows question-referred exposure parameters with clearly reduced dose, so e.g. for fracture exclusion 73 kV/12.5 mAs and to skull measurement 73 kV/4 mAs.

  14. Reduction of radiation dose by using digital luminescence radiography compared to conventional screen film system with grid cassette

    International Nuclear Information System (INIS)

    Heyne, J.P.; Merbold, H.; Neumann, R.; Freesmeyer, M.; Jonetz-Mentzel, L.; Kaiser, W.A.; Sehner, J.

    1999-01-01

    Purpose: How much can the radiation dose be reduced for skull radiography by using digital luminescence radiography (DLR) compared to a conventional screen film system with a grid cassette? Methods and Materials: A skull phantom (3M) was X-rayed in anterior-posterior orientation using both a conventional screen film system with grid cassette and DLR (ADC-70, Agfa). The tube current time product (mAs) was diminished gradually while keeping the voltage constant. The surface entrance dose was measured by a sensor of Dosimax (Wellhoefer). Five investigators evaluated the images by characteristic and critical features, spatial resolution and contrast. Results: The surface entrance dose at 73 kV/22 mAs was 0,432 mGy in conventional screen film system and 0,435 mGy in DLR. The images could be evaluated very well down to an average dose of 71% (0,308 mGy; SD 0,050); sufficient images were obtained down to an average dose of 31% (0,136 mGy; SD 0,065). The resolution of the line pairs were reduced down to a 2 levels depending on the investigator. Contrast was assessed as being very good to sufficient. The acceptance of the postprocessed images (MUSICA-software) was individually different and resultde in an improvement of the assessment of bone structures an contrast in higher dose ranges only. Conclusion: For the sufficient assessment of a possible fracture/of paranasal sinuses/of measurement the skull the dose can be reduced to at least 56% (31%; SD 14,9%)/40% (27%; SD 9,3%)/18% (14%; SD 4,4%). Digital radiography allows question-referred exposure parameters with clearly reduced dose, so e.g. for fracture exclusion 73 kV/12,5 mAs and to skull measurement 73 kV/4 mAs. (orig.) [de

  15. Relationship of Compressed Breast Thickness and Average Glandular Dose According to Focus/Filter

    International Nuclear Information System (INIS)

    Lee, In Ja

    2009-01-01

    The study examined the relationship between the compressed breast thickness and Average Glandular Dose (AGD) among 1,969 outpatients who went through breast X-ray in a university hospital for 10 months from July 1st, 2007 to April 30th, 2008. Then it analyzed the result acquired from 3,900 cases of Cranio-Caudal (CC) view, especially, when the breasts were compressed (13-15daN). The following is the conclusion driven from the relationship analysis. 1. The subjects aged in 40s and 50s were 2,679 out of 3,900 cases and this figure was 68.69% in all. 2. In terms of distribution depending on focus/filter, 41.0% was Mo/Mo, 34.8% was Mo/Rh, and 24.2% was Rh/Rh. 3. In terms of compressed breast thickness depending on focus/filter, the average thickness was 26.91 mm at Mo/Mo, 38.84 mm at Mo/Rh, and 48.80 mm at Rh/Rh. The average thickness of the entire cases was shown to be 36.27 mm. 4. AGD depending on focus/filter was 1.27 mGy at Mo/Mo, 1.55 mGy at Mo/Rh, and 1.42 mGy at Rh/Rh. The average glandular dose of the entire cases was shown to be 1.43 mGy. 5. The relationship of AGD depending on compressed breast thickness at Mo/Mo was y=0.0318x + 0.470 while it was y=0.0206x + 0.709 at Mo/Rh and y=0.0248x + 0.335 at Mo/Rh. It was highly influenced by the compressed breast thickness, however, more variation was detected at Mo/Mo depending on breast thickness.

  16. Computation of thyroid doses and carcinogenic radiation risks to patients undergoing neck CT examinations

    International Nuclear Information System (INIS)

    Huda, W.; Spampinato, M. V.; Tipnis, S. V.; Magill, D.

    2013-01-01

    The aim of the study was to investigate how differences in patient anatomy and CT technical factors in neck CT impact on thyroid doses and the corresponding carcinogenic risks. The CTDI vol and dose-length product used in 11 consecutive neck CT studies, as well as data on automatic exposure control (AEC) tube current variation(s) from the image DICOM header, were recorded. For each CT image that included the thyroid, the mass equivalent water cylinder was estimated based on the patient cross-sectional area and average relative attenuation coefficient (Hounsfield unit, HU). Patient thyroid doses were estimated by accounting for radiation intensity at the location of the patient's thyroid, patient size and the scan length. Thyroid doses were used to estimate thyroid cancer risks as a function of patient demographics using risk factors in BEIR VII. The length of the thyroid glands ranged from 21 to 54 mm with an average length of 42±12 mm. Water cylinder diameters corresponding to the central slice through the patient thyroid ranged from 18 to 32 cm with a mean of 25±5 cm. The average CTDI vol (32-cm phantom) used to perform these scans was 26±6 mGy, but the use of an AEC increased the tube current by an average of 44 % at the thyroid mid-point. Thyroid doses ranged from 29 to 80 mGy, with an average of 55±19 mGy. A 20-y-old female receiving the highest thyroid dose of 80 mGy would have a thyroid cancer risk of nearly 0.1 %, but radiation risks decreased very rapidly with increasing patient age. The key factors that affect thyroid doses in neck CT examinations are the radiation intensity at the thyroid location and the size of the patient. The corresponding patient thyroid cancer risk is markedly influenced by patient sex and age. (authors)

  17. TARDEC 30-Year Strategy Value Stream Analysis

    Science.gov (United States)

    2015-07-01

    compilation, threat assessment, prioritization and neutralization of enemy human, mobile, terrestrial and airborne C4ISR collection assets and...investments, leverage and influence national ICME and Materials Genome Initiative (MGI) programs. ii. Leverage materials being developed within the...Trade-space, META or Reduced Order tool development/enhancement M&S o Reduce logistic burden (fuel and water usage) M&S TARDEC Software

  18. Measurement of volatile evolution from polyurethane induced by accelerated ion beam irradiation

    International Nuclear Information System (INIS)

    Murphy, J.J.

    2003-01-01

    Irradiation of polymer samples using an accelerated beam of He 2+ ions passed through a 10μm thick window of havar foil has been performed. Such irradiation simulates the effects of large α radiation doses, on a vastly reduced time-scale. Analysis of volatiles evolved during irradiation is performed by a residual gas analyser (RGA), which is located close to the sample chamber. Presented in this paper are the results obtained during a radiation study on polyester/MDI based polyurethane materials. During high dose rate irradiation a number of high mass species were observed. A comparison between two similar polyurethanes formulated with slightly different polyesters indicated some differences. They were, however, too minor to link to specific degradation mechanisms. The dominant degradation products evident to the RGA at low dose rates were H 2 , CO and CO 2 . A series of polyurethane samples previously conditioned by γ irradiation at doses between 0 and 5MGy were irradiated in the ion beam. Identification of differences in trends in the rates of volatile evolution between these samples indicated the precise vacuum conditions at the time of irradiation had a major influence. There was also an indication that the surface of the sample had a small effect on rates of volatile evolution. Comparative plots of CO and CO 2 evolution for a series of 1MGy irradiations indicated variations in behaviour between samples with different γ doses. Evolution during the first 1MGy was inhibited for the unirradiated sample, the extent of inhibition diminished with increasing γ dose and was no longer evident in a sample with 1.5MGy γ dose. H 2 does not show an equivalent inhibition. Evidence for a low dose crosslinking reaction is put forward as a reason for the inhibition. Chemical reaction mechanisms are postulated and used to explain differences in the behaviour observed

  19. Perfusion CT of the Brain and Liver and of Lung Tumors: Use of Monte Carlo Simulation for Patient Dose Estimation for Examinations With a Cone-Beam 320-MDCT Scanner.

    Science.gov (United States)

    Cros, Maria; Geleijns, Jacob; Joemai, Raoul M S; Salvadó, Marçal

    2016-01-01

    The purpose of this study was to estimate the patient dose from perfusion CT examinations of the brain, lung tumors, and the liver on a cone-beam 320-MDCT scanner using a Monte Carlo simulation and the recommendations of the International Commission on Radiological Protection (ICRP). A Monte Carlo simulation based on the Electron Gamma Shower Version 4 package code was used to calculate organ doses and the effective dose in the reference computational phantoms for an adult man and adult woman as published by the ICRP. Three perfusion CT acquisition protocols--brain, lung tumor, and liver perfusion--were evaluated. Additionally, dose assessments were performed for the skin and for the eye lens. Conversion factors were obtained to estimate effective doses and organ doses from the volume CT dose index and dose-length product. The sex-averaged effective doses were approximately 4 mSv for perfusion CT of the brain and were between 23 and 26 mSv for the perfusion CT body protocols. The eye lens dose from the brain perfusion CT examination was approximately 153 mGy. The sex-averaged peak entrance skin dose (ESD) was 255 mGy for the brain perfusion CT studies, 157 mGy for the lung tumor perfusion CT studies, and 172 mGy for the liver perfusion CT studies. The perfusion CT protocols for imaging the brain, lung tumors, and the liver performed on a 320-MDCT scanner yielded patient doses that are safely below the threshold doses for deterministic effects. The eye lens dose, peak ESD, and effective doses can be estimated for other clinical perfusion CT examinations from the conversion factors that were derived in this study.

  20. Structural studies using X-ray absorption and scattering techniques

    International Nuclear Information System (INIS)

    Ericson, Agneta.

    1989-01-01

    The thesis presents extended X-ray absorption fine structure, EXAFS, and large angle X-ray scattering, LAXS, techniques; instrumentation, data collection and reduction, and applications. These techniques have been used to determine the structures of magnesium halides and organomagnesium halides in diethyl ether and tetrahydrofuran solution. The iodides were used for the LAXS measurements and Br K edge EXAFS data were collected for the corresponding bromides. Two different complexes are present in the diethyl ether solution of magnesium iodide; a polymeric chain-type structure where magnesium is tetrahedrally coordinated, as well as dimeric complex with octahedrally coordinated magnesium. Solvated MgI + is the dominating species in tetrahydrofuran solution. The organomagnesium halides are present in diethyl ether solution as both solvated monomeric and dimeric complexes. Magnesium coordinates a halide ion, an alkyl or aryl group and four solvent molecules octahedrally in the monomeric complex. In the dimeric complex magnesium is octahedrally coordinated by two bridging halide ions, an alkyl or aryl group and three solvent molecules. The distribution of monomeric and dimeric complexes in various solutions are given by a dimerisation constant, K dl . The results indicate that the Schlenk equilibrium is present in these solutions, however, in an extended form. In diethyl ether solution, where MgX 2 does not dissociate, no MgX 2 complex and thereby no Schlenk equilibrium has been observed. In tetrahydrofuran solution MgI 2 has dissociated into mainly MgI + and I - . This indicates that the concentration of MgI 2 is low and that the Schlenk equilibrium should be expanded even further to include the dissociation equilibrium of the magnesium halide. In the thesis Fe K edge EXAFS data collected for the semireduced form of protein A of methane monooxygenase from Methylococcus capsulatus, are also presented. (139 refs.)

  1. Radiation doses in head CT examinations in Serbia: comparison among different CT units

    International Nuclear Information System (INIS)

    Arandjic, D.; Ciraj-Bjelac, O.; Bozovic, P.; Stankovic, J.; Hadnadjev, D.; Stojanovic, S.

    2012-01-01

    A rapid increase in number of Computed Tomography (CT) examinations has been observed world wide. As haed CT is the most frequent CT examination, the purpose of this study was to collect and analyse patient doses in children and adults in different CT units for this procedure. The study included 8 CT units from three manufacturers (Siemens, Toshiba and General Electric). Data for adults and pediatric patients were collected in terms of CTDIvol and DLP values. The doses were estimated as a mean value of 10 patients on each CT unit. For pediatrics, doses were collected for four age groups (0-1year, >1-5years, >5-10years and >10-15years). Comparing different manufacturers and the same number of detector rows it was observed that, in case of 16 slices units, doses were very similar on Siemens and General Electric scanner. CTDIvol and DLP on Siemens scanner were 60 mGy and 1066 mGy·cm, respectively, while on General Electric those values were 66 mGy and 1050 mGy·cm. However, this trend was not observed in case of 64 slices units. CTDIvol and DLP values collected on Toshiba were much higher (177 mGy and 2109 mGy·cm) than in case of Siemens scanner (59 mGy and 1060 mGy·cm). Doses on 16 and 64 slices Siemens scanners were very similar, while on 4 slices were higher. Except in two units, doses were were in line with DRLs. In case of pediatrics, doses increase with patient age and again Siemens scanner showed the lowest values while the highest were observed on Toshiba. (authors)

  2. Teratological effects of Cr (vi) on liver of cyprinus carpio

    International Nuclear Information System (INIS)

    Sayybah, S.; Tanveer, A.

    2008-01-01

    Cyprinus carpio liver showed disturbed histological architecture due to prolonged exposure of various sublethal chromium hexavalent doses (25,50,75,100,125 and 150mg/l) in temporal dose pattern as compared to control. In treated fish liver shrunken hepatocytes (25, 50, 75, 100mg/l) with isolated vacuole (75. 100mg/I), pyknotic nuclei and ruptured canaliculi (125, 150mg/l) were observed while control showed normal tissue structure. (author)

  3. Variation of Archaeal Populations Along a Salinity Gradient in the Pearl River Estuary, China: Implications for Synergy Between Different Metabolic Processes

    Science.gov (United States)

    Zhang, C.

    2016-02-01

    Marine archaea mainly include marine group I (MGI) that function as chemolithoautotrophs growing on ammonia and marine group II (MGII) that live heterotrophically. In this study, we quantified the abundance of MGI (represented by archaeal amoA gene) and MGII (16S rRNA gene) using qPCR in the water column of different salinities (A: 0.8‰; B: 18.1‰; C: 23.9‰: D: 31‰) in the Pearl River Estuary over a 12-month period. The results showed that the abundance of MG II in site C (8.5±10.1×107 copies/L) was significantly higher than the other three sites (A: 3.5±8.8×105 copies/L; B: 2.7±4.5×107 copies/L; D: 2.2±4.4×107 copies/L) in all seasons, indicating the perennial blooming of MGII that might be due to the optimal combination of available organic carbon and salinity at this site. We also observed that the correlation between MGI and MGII became better toward the marine water and was significant at site D (R2: A, 0.06; B, 0.1; C, 0.24; D, 0.64), indicating the potential functional relationship between them with increasing salinity. This allows us to hypothesize that the growth of MGI in the coastal site is more dependent on release of ammonia from organic matter degradation by MGII and other heterotrophic organisms. The Pearl River Estuary may be an ideal environment for testing this hypothesis, which may provide insight into the mechanisms of carbon cycle performed by different archaea in continental margin systems.

  4. Dosimetric evaluation in panoramic and tele-radiography procedures

    International Nuclear Information System (INIS)

    Oliveira, Georgge Gomes

    2004-01-01

    The present work had as an objective to evaluate the skin surface entrance dose in panoramic and tele radiography procedures in three clinics in Recife - Pernambuco - Brazil, and to contribute with data for the determination of reference levels for super cited extra oral procedures, for this purpose, operational conditions in 3 clinics were evaluated in Recife, aiming to evaluate the existence and integrity of the radioprotection equipment, manner and conditions of image processing; and radiographic equipment parameters such as the dimension of the irradiation filed, the total filtration, the exposure time and the potential applied to the X ray tube. For an estimation of the skin entrance dose of the patient, the phantom Randon Alderson and thermoluminescence dosemeters were used. From these values and the conversion factors determined by the Monte Carlo technique, with the phantom MAX it was possible to estimate the dose absorbed in the organ due to the tele radiography procedures. Regarding panoramic radiography the study showed that the more elevated doses occurred in the parotid gland region which is near rotational venters. In the case of tele radiography the highest dose value occurred in the regions corresponding to the temporal lobe of the brain, followed by linfonodes, ears and parotid glands. The doses absorbed in the eyes and the thyroid gland were, 0.037 mGy and 0.002 mGy in Clinic A and 0.062 mGy and 0.003 mGy in Clinic C, respectively. Regarding equipment test, inadequacy was found in the beam collimation in Clinic A and in the reproducibility of the X ray exposure in Clinic C. The total filtration in both clinics was inadequate.(author)

  5. Dosimetric evaluation in panoramic and tele-radiography procedures; Avaliacao dosimetrica em procedimentos de radiografia panoramica e teleradiografias

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Georgge Gomes

    2004-07-01

    The present work had as an objective to evaluate the skin surface entrance dose in panoramic and tele radiography procedures in three clinics in Recife - Pernambuco - Brazil, and to contribute with data for the determination of reference levels for super cited extra oral procedures, for this purpose, operational conditions in 3 clinics were evaluated in Recife, aiming to evaluate the existence and integrity of the radioprotection equipment, manner and conditions of image processing; and radiographic equipment parameters such as the dimension of the irradiation filed, the total filtration, the exposure time and the potential applied to the X ray tube. For an estimation of the skin entrance dose of the patient, the phantom Randon Alderson and thermoluminescence dosemeters were used. From these values and the conversion factors determined by the Monte Carlo technique, with the phantom MAX it was possible to estimate the dose absorbed in the organ due to the tele radiography procedures. Regarding panoramic radiography the study showed that the more elevated doses occurred in the parotid gland region which is near rotational venters. In the case of tele radiography the highest dose value occurred in the regions corresponding to the temporal lobe of the brain, followed by linfonodes, ears and parotid glands. The doses absorbed in the eyes and the thyroid gland were, 0.037 mGy and 0.002 mGy in Clinic A and 0.062 mGy and 0.003 mGy in Clinic C, respectively. Regarding equipment test, inadequacy was found in the beam collimation in Clinic A and in the reproducibility of the X ray exposure in Clinic C. The total filtration in both clinics was inadequate.(author)

  6. Effects of {gamma} and neutron irradiation on the optical absorption of pure silica core single-mode optical fibres from Nufern

    Energy Technology Data Exchange (ETDEWEB)

    Calderon, A. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Martinez-Rivero, C. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Matorras, F. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Rodrigo, T. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Sobron, M. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Vila, I. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Virto, A.L. [Instituto de Fisica de Cantabria, CSIC-University of Cantabria, Santander (Spain); Alberdi, J. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Arce, P. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Barcala, J.M. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Calvo, E. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Ferrando, A. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain)]. E-mail: Antonio.Ferrando@ciemat.es; Josa, M.I. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Luque, J.M. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Molinero, A. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Navarrete, J. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Oller, J.C. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Valdivieso, P. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Yuste, C. [CIEMAT, Particle Physics, Avda. Complutense 22, 28040, Madrid (Spain); Fenyvesi, A. [Institute of Nuclear Research, ATOMKI, Debrecen (Hungary); Molnar, J. [Institute of Nuclear Research, ATOMKI, Debrecen (Hungary)

    2006-09-15

    A measurement of the optical absorption, induced by photon irradiation up to a dose of 0.9 MGy, in Nufern silica core single-mode optical fibres is presented. In addition, the fibres were irradiated with neutrons, up to a total fluence of 2x10{sup 14} cm{sup -2} and the induced optical absorption was evaluated for four different wavelengths: 630, 670, 681 and 785 nm.

  7. SU-D-209-03: Radiation Dose Reduction Using Real-Time Image Processing in Interventional Radiology

    Energy Technology Data Exchange (ETDEWEB)

    Kanal, K; Moirano, J; Zamora, D; Stewart, B [University Washington, Seattle, WA (United States)

    2016-06-15

    Purpose: To characterize changes in radiation dose after introducing a new real-time image processing technology in interventional radiology systems. Methods: Interventional radiology (IR) procedures are increasingly complex, at times requiring substantial time and radiation dose. The risk of inducing tissue reactions as well as long-term stochastic effects such as radiation-induced cancer is not trivial. To reduce this risk, IR systems are increasingly equipped with dose reduction technologies.Recently, ClarityIQ (Philips Healthcare) technology was installed in our existing neuroradiology IR (NIR) and vascular IR (VIR) suites respectively. ClarityIQ includes real-time image processing that reduces noise/artifacts, enhances images, and sharpens edges while also reducing radiation dose rates. We reviewed 412 NIR (175 pre- and 237 post-ClarityIQ) procedures and 329 VIR (156 preand 173 post-ClarityIQ) procedures performed at our institution pre- and post-ClarityIQ implementation. NIR procedures were primarily classified as interventional or diagnostic. VIR procedures included drain port, drain placement, tube change, mesenteric, and implanted venous procedures. Air Kerma (AK in units of mGy) was documented for all the cases using a commercial radiation exposure management system. Results: When considering all NIR procedures, median AK decreased from 1194 mGy to 561 mGy. When considering all VIR procedures, median AK decreased from 49 to 14 mGy. Both NIR and VIR exhibited a decrease in AK exceeding 50% after ClarityIQ implementation, a statistically significant (p<0.05) difference. Of the 5 most common VIR procedures, all median AK values decreased, but significance (p<0.05) was only reached in venous access (N=53), angio mesenteric (N=41), and drain placement procedures (N=31). Conclusion: ClarityIQ can reduce dose significantly for both NIR and VIR procedures. Image quality was not assessed in conjunction with the dose reduction.

  8. Evaluation of surface radiation dose to the thyroid gland and the gonads during routine full-mouth intraoral periapical and maxillary occlusal radiography

    Directory of Open Access Journals (Sweden)

    Soheyl Sheikh

    2010-01-01

    Full Text Available Aim: The quantitative aspects of radiation doses to critical organs can help the dental professionals to take the necessary radiation protective measures as deemed necessary and can help the general public to allay radiation exposure fear in dental radiography, if any. Our study determines the surface radiation dose to thyroid and gonads in full-mouth intraoral periapical (IOPA and maxillary occlusal radiography.Materials and Methods: A total number of 120 subjects participated in the study. The surface radiation dose was estimated to the thyroid gland and the gonads in full-mouth IOPA radiography using 10 IOPA (E speed films and in maxillary occlusal radiography. The measurements were calculated using a digital pocket dosimeter (PD-4507.Results: The average dose at the thyroid gland level during full-mouth intraoral and maxillary occlusal radiography was estimated to be 10.93 mRads (1.093 Χ 10 -2 mGy and 0.4 mRads (4.0 Χ 10 -2 mGy, respectively. The average surface radiation dose at the gonadal region during a full mouth intraoral and maxillary occlusal radiography was estimated to be 1.5 mRads (1.5 Χ 10 -2 mGy and 0.15 mRads (1.5 Χ 10 -3 mGy, respectively. Conclusion: Our results suggest that although the radiation exposure doses to critical organs namely thyroid and gonads is within the safe limits still precautionary measures for these organs are advocated.

  9. Radiation dose in critical organs due to non-coplanar irradiation of the pituitary gland

    International Nuclear Information System (INIS)

    Schulte, R.W.M.; Rittmann, K.L.; Meinass, H.J.; Rennicke, P.

    1996-01-01

    In order to estimate the somatic and genetic risk associated with a non-coplanar linac-based radiation technique of the pituitary gland, systematic secondary-dose measurements in a phantom and sample measurements of the dose near critical organs of patients were performed. For measurements of the dose outside the primary radiation field an acrylic-PVC phantom was used which was irradiated with a single field (4x4 cm 2 ). Eight patients with pituitary tumors were treated isocentrically with a combination of sagittal and transverse rotational arcs. To measure the dose in critical organs, LiF thermoluminescence dosimeters (TLD) in chip form were placed onto 1 eyelid, the skin over the thyroid, and the patient's clothes covering the region of breasts and ovaries of female patients and the testicles of male patients. Measurements were performed for all patients during 1 sagittal irradiation and for the majority of patients during 1 transverse irradiation. The phantom measurements demonstrated that the secondary dose measured on the patients surface can be considered as a good approximation for the dose in adjacent organs. The median dose in critical organs for sagittal irradiation was in the range of 25.8 mGy (eyes) to 1.9 mGy (testicles), and for transverse irradiation in the range of 23.3 mGy (eyes) to 1.3 mGy (testicles). The ratio of median organ doses for sagittal and transverse irradiation was 2.1 for the thyroid gland, 1.1 for the eyes, and 1.5 for the other organs. The dose in critical organs due to non-coplanar irradiation of the pituitary gland is only a small fraction of the dose delivered to the reference point of the planning target volume. The risk of a radiation-induced tumor and a genetic consequence associated with these small doses is generally less than 1% and 0.1%, respectively. (orig./MG) [de

  10. Contrast monitoring techniques in CT pulmonary angiography: An important and underappreciated contributor to breast dose

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, D.P., E-mail: dpmmitchell@gmail.com; Rowan, M., E-mail: mrowan@mater.ie; Loughman, E., E-mail: eloughman@mater.ie; Ridge, C.A., E-mail: cridge@mater.ie; MacMahon, P.J., E-mail: pmacmahon@mater.ie

    2017-01-15

    Objective: The aims of our study were to evaluate the contribution of contrast-monitoring techniques to breast dose in pregnant and non-pregnant women, and to investigate the effect of a reduced peak kilovoltage (kV) monitoring scan protocol on breast dose and Computed Tomography Pulmonary Angiography (CTPA) diagnostic quality. Materials and methods: Single center retrospective study of 221 female patients undergoing a reduced kV 80 kV contrast-monitoring CTPA protocol compared to 281 patients using the conventional 120 kV contrast-monitoring protocol (Siemens Somatom Definition AS + ). 99 pregnant patients analyzed separately. ImPACT dosimetry software was used to calculate dose. Group subsets were evaluated to assess CTPA diagnostic quality. Results: The contrast-monitoring component of a CTPA study constituted 27% of the overall breast dose when using a standard 120 kV protocol compared to only 7% of the overall breast dose in the 80 kV study group. The dose to the breast from the contrast-monitoring component alone was reduced by 79% in the non-pregnant patients (0.36mGy ± 0.37 versus 1.7mGy ± 1.02; p < 0.001), and by 88% in the pregnant population (0.25 mGy ± 0.67 versus 2.24mGy ± 1.61; p < 0.001). There was no statistical difference in CTPA diagnostic quality or timing. Conclusion: Despite a short scan length and relatively small DLP, contrast-monitoring techniques (test-bolus or bolus-tracked) set at 120 kV can account for 27% of the overall breast dose accrued from a CTPA study. By decreasing the kilovoltage of the contrast-monitoring component, a significant reduction in breast dose for pregnant and non-pregnant female patients can be achieved without affecting CTPA quality or timing.

  11. Survey of mammography practice in Croatia: Equipment performance, image quality and dose

    International Nuclear Information System (INIS)

    Faj, D.; Stimac, D.; Ivezic, Z.; Kasabasic, M.; Ivkovic, A.; Posedel, D.; Kubelka, D.; Ilakovac, V.; Brnic, Z.; Bjelac, O.C.

    2008-01-01

    A national audit of mammography equipment performance, image quality and dose has been conducted in Croatia. Film-processing parameters, optical density (OD), average glandular dose (AGD) to the standard breast, viewing conditions and image quality were examined using TOR(MAM) test object. Average film gradient ranged from 2.6 to 3.7, with a mean of 3.1. Tube voltage used for imaging of the standard 45 mm polymethylmethacrylate phantom ranged from 24 to 34 kV, and OD ranged from 0.75 to 1.94 with a mean of 1.26. AGD to the standard breast ranged from 0.4 to 2.3 mGy with a mean of 1.1 mGy. Besides clinical conditions, the authors have imaged the standard phantom in the referent conditions with 28 kV and OD as close as possible to 1.5. Then, AGD ranged from 0.5 to 2.6 mGy with a mean of 1.3 mGy. Image viewing conditions were generally unsatisfying with ambient light up to 500 lx and most of the viewing boxes with luminance between 1000 and 2000 cd per m 2 . TOR(MAM) scoring of images taken in clinical and referent conditions was done by local radiologists in local image viewing conditions and by the referent radiologist in good image viewing conditions. Importance of OD and image viewing conditions for diagnostic information were analysed. The survey showed that the main problem in Croatia is the lack of written quality assurance/quality control (QA/QC) procedures. Consequently, equipment performance, image quality and dose are unstable and activities to improve image quality or to reduce the dose are not evidence-based. This survey also had an educational purpose, introducing in Croatia the QC based on European Commission Guidelines. (authors)

  12. Kinetic characterization of the first peak of natural fluorite from low ...

    African Journals Online (AJOL)

    Fluorite samples were irradiated with a low dose-rate (40 μGys-1 ) β- irradiation source to a test dose of 1.2 mGy and the heating rates of β = 1,3 and 5o Cs were considered, in order to minimize the effect of temperature lag. The role of thermal quenching (W) was investigated by evaluating the activation energy using the ...

  13. The application of retrospective luminescence dosimetry in areas affected by fallout from the semipalatinsk nuclear test site: an evaluation of potential.

    Science.gov (United States)

    Bailiff, I K; Stepanenko, V F; Göksu, H Y; Jungner, H; Balmukhanov, S B; Balmukhanov, T S; Khamidova, L G; Kisilev, V I; Kolyado, I B; Kolizshenkov, T V; Shoikhet, Y N; Tsyb, A F

    2004-12-01

    Luminescence retrospective dosimetry techniques have been applied with ceramic bricks to determine the cumulative external gamma dose due to fallout, primarily from the 1949 test, in populated regions lying NE of the Semipalatinsk Nuclear Test Site in Altai, Russia, and the Semipalatinsk region, Kazakhstan. As part of a pilot study, nine settlements were examined, three within the regions of highest predicted dose (Dolon in Kazakshstan; Laptev Log and Leshoz Topolinskiy in Russia) and the remainder of lower predicted dose (Akkol, Bolshaya Vladimrovka, Kanonerka, and Izvestka in Kazakshstan; Rubtsovsk and Kuria in Russia) within the lateral regions of the fallout trace due to the 1949 test. The settlement of Kainar, mainly affected by the 24 September 1951 nuclear test, was also examined. The bricks from this region were found to be generally suitable for use with the luminescence method. Estimates of cumulative absorbed dose in air due to fallout for Dolon and Kanonerka in Kazakshstan and Leshoz Topolinskiy were 475 +/- 110 mGy, 240 +/- 60 mGy, and 230 +/- 70 mGy, respectively. The result obtained in Dolon village is in agreement with published calculated estimates of dose normalized to Cs concentration in soil. At all the other locations (except Kainar) the experimental values of cumulative absorbed dose obtained indicated no significant dose due to fallout that could be detected within a margin of about 25 mGy. The results demonstrate the potential suitability of the luminescence method to map variations in cumulative dose within the relatively narrow corridor of fallout distribution from the 1949 test. Such work is needed to provide the basis for accurate dose reconstruction in settlements since the predominance of short-lived radionuclides in the fallout and a high degree of heterogeneity in the distribution of fallout are problematic for the application of conventional dosimetry techniques.

  14. Morphological and histological studies on freshwater prawn Macrobrachium rosenbergii (de man) irradiated with (60)Co gamma radiation.

    Science.gov (United States)

    Stalin, A; Broos, K V; Sadiq Bukhari, A; Syed Mohamed, H E; Singhal, R K; Venu-Babu, P

    2013-11-15

    This study was framed to investigate the (60)Co gamma radiation induced morphological and histological variations in freshwater prawn Macrobrachium rosenbergii. The LD50 value of (60)Co gamma irradiated M. rosenbergii observed (by probit analysis) at 30 Gy. Prawns were irradiated to four different dose levels (3 mGy, 30 mGy, 300 mGy and 3,000 mGy) using Theratron Phoenix TeleCobalt Unit [P-33] and one control group (without irradiation) maintained separately. Irradiated groups exhibited several morphological variations such as discoloration; damaged rostrum; opaque coloration in cephalothorax; black bands and dot formation in abdomen; deformed uropods and telson in tail regions when compared with control group. The Hepato Somatic Index reflected the severity of radiation on hepatopancreas. Histological variations in gills, hepatopancreas and muscles of irradiated groups were observed. In gills, structural changes such as swollen and fused lamellae, abnormal gill tips, hyperplasic, necrotic and clavate-globate lamellae were observed in gamma irradiated prawns. Accumulation of hemocytes in hemocoelic space, interstitial sinuses filled with abnormal infiltrated hemocytes, the tubular epithelium with ruptured basal laminae, abnormal and coagulated lumen, necrotic tubules, thickened basal laminae, tissue debris, necrotic hepatocytes were observed in irradiated prawn hepatopancreas. In muscle, shrinkage of muscular fiber and necrotic musculature were observed in irradiated prawns. These structural alterations of the organs it is felt could affect the vital physiological functions such as respiration, osmotic and ionic regulation in gills and muscles; absorption, storage and secretion of the hepatopancreas which in turn could adversely affect the growth and survival of freshwater prawn M. rosenbergii. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Effect of dietary protein quality on the resistance of rats to total body radiation

    Energy Technology Data Exchange (ETDEWEB)

    Bounous, G.; Pageau, R.

    1983-02-01

    Young rats have been fed four defined-formula diets before and after ..gamma..-irradiation (700 rd (7.0 Gy), 75 rd/min (750 mGy), 80 cm from the source, total body). Animals eating a diet containing lactalbumin hydrolyzate (20 g/100 g diet) exhibited less anorexia and weight loss following ..gamma..-rays than a corresponding group eating casein hydrolyzate (20 g/100 g diet).

  16. Synergistic effects of methyl methanesulfonate and X rays in inducing somatic mutations in the stamen hairs of Tradescantia clones, KU 27 and BNL 4430

    International Nuclear Information System (INIS)

    Ichikawa, Sadao; Yamaguchi, Akihiko; Okumura, Mikiko

    1993-01-01

    Young influorescences of Tradescantia clones KU 27 and BNL 4430, the both of which are blue/pink heterozygotes and have been demonstrated to be highly sensitive to alkylating agents, were exposed either to aqueous solutions of methyl methanesulfonate (MMS) for 16 hr alone (at 0.005 to 0.02% for KU 27 and at 0.005% for BNL 4430) or to acute 150 kVp X rays alone (161 to 531 mGy for Ku 27 and 501 to 976 mGy for BNL 4430), or in combinations (134 to 448 mGy for KU 27 and 458 to 865 mGy for BNL 4430 after the 0.005% MMS treatment). The induced somatic pink mutation frequencies per hair-cell division were studied and compared, and clone BNL 4430 was found to be nearly two times more sensitive to MMS than clone KU 27, while the X-ray-induced mutation frequencies in the latter was about 1.5 times higher than those in the former. The lower sensitivity to MMS of clone KU 27 (as compared with BNL 4430) was nevertheless about 5.6 times higher as compared with the responses of clone BNL 02 to MMS reported earlier, proving the high sensitivities of the two clones used in the present study. Clear synergistic effects of MMS and X rays were observed in the both clones, indicating that the mechanisms of inducing mutations are common at least in part between MMS and X rays. (author)

  17. Genetic instability of T-lymphocytes grown clonally in vitro of A-bomb survivors

    International Nuclear Information System (INIS)

    Hamasaki, Kanya; Kusunoki, Yoichiro; Nakajima, Eiji; Takahashi, Norio; Nakachi, Kei; Nakamura, Nori; Kodama, Yoshiaki

    2009-01-01

    Authors have reported their studies on genetic instability of A-bomb survivors' peripheral T-lymphocytes in vivo that chromosomal instability is not observed in the cells. This paper reports their further studies to see genetic instability that may occur in clones of T-cells cultured long, for the purpose of data collection at chromosome level. Subjects were the T-cells of 2 female A-bomb survivors (Case 1: age 65 y, exposed at age 20 y with marrow estimated dose DS02 (Dosimetry system 2002) of 1950 mGy; and Case 2: 72 y, 13 y, 1150 mGy, respectively) and age / sex matched 2 control females (Case 3: 63 y, 19 y, 1.3 mGy; and Case 4: 70 y, 13 y, 1.7 mGy, respectively). T-cells were those freeze-stored (Case 1, 3, and 4) and freshly prepared (Case 2). Monocytes were isolated by Ficoll procedure and cloned in 96-hole plate as previously described. Colonies formed were cultured in 24-hole plate with CD3/CD28 T-cell proliferation beads for 4 weeks in average (Case 2, 3 and 4; ave. cell cycles 23-25) and cells of Case 1 (cloned and freeze-stored previously) were cultured similarly. Chromosome specimens were prepared routinely, and 100 cells of each clone were subjected to mFISH observation for image analysis with CytoVision (Applied Imaging) to detect the aberrations like translocation, derived and dicentric chromosomes. No significant difference in stable chromosome aberrations yielded during the long culture in vitro was found between exposed and control groups, suggesting that genetic instability due to radiation exposure had not occurred in this experiment. (K.T)

  18. Outcomes of pregnancy in function of radiation dose to ovaries following a treatment with I131 for a differentiated thyroid cancer

    International Nuclear Information System (INIS)

    Garsi, J.P.; Rubino, C.; Labbe, M.; Vathaire, F. de; Garsi, J.P.; Schlumberger, M.; Rubino, C.; Ricard, M.; Labbe, M.; Vathaire, F. de; Garsi, J.P.; Rubino, C.; Labbe, M.; Vathaire, F. de; Schvartz, C.; Henri-Amar, M.; Bardet, S.; Ceccarelli, C.

    2008-01-01

    Radiations are mutagen. During a treatment for a differentiated cancer of thyroid, the minimal activity of I 131 given to the patient is 3700 MBq producing a radiation dose to ovaries estimated to 140 mGy. In spite of the importance of this dose, few data on the outcomes of the pregnancy after irradiation are available. After our study it appears that the exposure to I 131 has no harmful effect on the outcomes of these pregnancies. (N.C.)

  19. Impact of low-dose CT scan in dual timepoint investigations: a phantom study

    DEFF Research Database (Denmark)

    Micheelsen, M A; Jensen, Mikael

    2011-01-01

    within predetermined error limits. For a hot sphere to background activity concentration ratio of 1:5, the average uptake (normalised by the time corrected input activity concentration) in a sphere of 6 cm3 was found to be 0.90 ± 0.08 for the standard scan, yielding a dose of 5.5 mGy, and 0.90 ± 0...

  20. ANALISIS KARAKTERISTIK KANDUNGAN PENCEMAR AIR LIMBAH DAN PROSES PENGOLAHAN AIR MINUM KABUPATEN BADUNG

    Directory of Open Access Journals (Sweden)

    AWANG ERRY SOFYAR IRAWAN

    2015-06-01

    Full Text Available Installation of water treatment is the required infrastructure in meeting the needs of clean water. During the process of water treatment it produces waste water as a byproduct that could potentially cause pollution if not properly treated. The research purposes of the study are to determine the effectiveness of compliance procedures for waste water treatment, the quality and quantity of waste water and its impact to the environment, as well as providing alternatives for waste water management strategies. Determination of samples were conducted by using purposive sampling method. Samples were taken at two sewer sedimentation and filtration points antl the other four points were taken in the water body and then compared with Governor of Bali Regulation No.8 year 2007. Samples were analywd both in situ and in the laboratory. To determine the effectiveness of the waste water treatment to the conformity assessment procedures, the field conditions were analyzed with a force-field analysis. The effectiveness of waste water management was categorized as moderate. The quality of waste water from the sedimentation basin shows the parameters of TSS (4957.50 mg/I and Mn (81.68 mg/I, of the tub filtration TSS (665 mg/I and Mn (12.60 mg/I. The quantity of waste sedimentation basin discharge (Q o.68 mg/sec, TSS pollutant load (3371.01 mg/sec, Mn (55.51 mg/sec, filtration basin discharge (Q o.68 mg/sec, load TSS pollutant (332.50 mg/sec, Mn (6.30 mg/sec. Based on the force-field analysis conducted, some alternative strategies were proposed such as building facilities for waste management, environmental m.inagement implementation based on the appropriate planning, implementation of waste water disposal permit including fulfill the technical conditions as required, technical capacity building of human resources, and land use.

  1. CT-guided screw fixation of vertical sacral fractures in local anaesthesia using a standard CT; CT-kontrollierte Schraubenosteosynthese von vertikalen Frakturen des hinteren Beckenringes in Lokalanaesthesie

    Energy Technology Data Exchange (ETDEWEB)

    Reuther, G.; Dehne, I. [Thueringen-Klinik, Saalfeld (Germany). Radiologische Klinik; Roehner, U.; Will, T.; Petereit, U. [Thueringen-Klinik, Saalfeld (Germany). Orthopaedics and Trauma Surgery

    2014-12-15

    To evaluate time efficiency, radiation dose, precision and complications of percutaneous iliosacral screw placement under CT-guidance in local anaesthesia. Retrospective analysis of 143 interventions in 135 patients during a period of 42 months. Implant failures could be evaluated in 85/182 screws and bony healing or refracturing in 46/182 screws. A total of 182 iliosacral screw placements in 179 vertical sacral fractures (105 unilateral, 37 bilateral) took place in 135 patients. 166/179 of the sacral fractures were detected in Denis zone 1, 10 in Denis zone 2 and 3 in Denis zone 3. No screw misplacements including the simultaneous bilateral procedures were noted. The average time for a unilateral screw placement was 23 minutes (range: 14-52 minutes) and 35 minutes (range: 21-60 minutes) for simultaneous bilateral screwing. The dose length product was 365 mGy x cm (range: 162-1014 mGy x cm) for the unilateral and 470 mGy x cm (range: 270-1271 mGy x cm) for the bilateral procedure. 1 gluteal bleeding occurred as the only acute minor complication (0.7%). Fracture healing was verified with follow-up CTs in 42/46 sacral fractures after screw placement. Backing out occurred in 12/85 screws between 6 and 69 days after intervention. In 8 patients contralateral stress fractures were detected after unilateral screw placement between day 10 and 127 (average: 48 days). CT-guided iliosacral screw placement in sacral fractures is a safe tool providing a very high precision. The radiation dose is in the order of a diagnostic CT of the pelvis for both unilateral and bilateral screws. Contralateral stress fractures in unilateral screw placements have to be considered during the first weeks after intervention.

  2. Comparison of the radiation dose from cone beam computed tomography and multidetector computed tomography in examinations of the hand; Vergleich der Strahlendosis von Cone-Beam Computertomografie und Multidetektor Computertomografie in Untersuchungen der Hand

    Energy Technology Data Exchange (ETDEWEB)

    Neubauer, J.; Neubauer, C.; Gerstmair, A.; Krauss, T.; Kotter, E.; Langer, M. [University Medical Center Freiburg (Germany). Dept. of Radiology; Reising, K. [University Medical Center Freiburg (Germany). Dept. of Orthopedics and Trauma Surgery; Zajonc, H. [University Medical Center Freiburg (Germany). Dept. of Plastic and Hand Surgery; Fiebich, M.; Voigt, J. [University of Applied Sciences, Giessen (Germany). Inst. of Medical Physics and Radiation Protection

    2016-05-15

    Comparison of radiation dose of cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) in examinations of the hand. Dose calculations were carried out by means of Monte Carlo simulations in MDCT and CBCT. A corpse hand was examined in a 320-row MDCT scanner and a dedicated extremities CBCT scanner with standard protocols and multiple low-dose protocols. The image quality of the examinations was evaluated by 5 investigators using a Likert scale from 1 (very good) to 5 (very poor) regarding depiction of cortical bone, cancellous bone, joint surfaces, soft tissues and artifacts. For a sum of ratings of all structures < 50 a good overall image quality was expected. The studies with at least good overall image quality were compared with respect to the dose. The dose of the standard examination was 13.21 (12.96 to 13.46 CI) mGy in MDCT and 7.15 (6.99 to 7.30 CI) mGy in CBCT. The lowest dose in a study with good overall image quality was 4.54 (4.43 to 4.64 CI) mGy in MDCT and 5.72 (5.59 to 5.85 CI) mGy in CBCT. Although the dose of the standard protocols in the CBCT is lower than in the MDCT, the MDCT can realize a good overall image quality at a lower dose than the CBCT. Dose optimization of CT examination protocols for the hand is useful in both modalities, the MDCT has an even greater potential for optimization.

  3. Dose-rate effects of protons on in vivo activation of nuclear factor-kappa B and cytokines in mouse bone marrow cells

    Energy Technology Data Exchange (ETDEWEB)

    Rithidech, K.N.; Rusek, A.; Reungpatthanaphong, P.; Honikel, L.; Simon, S.R.

    2010-05-28

    The objective of this study was to determine the kinetics of nuclear factor-kappa B (NF-{kappa}B) activation and cytokine expression in bone marrow (BM) cells of exposed mice as a function of the dose rate of protons. The cytokines included in this study are pro-inflammatory [i.e., tumor necrosis factor-alpha (TNF-{alpha}), interleukin-1beta (IL-1{beta}), and IL-6] and anti-inflammatory cytokines (i.e., IL-4 and IL-10). We gave male BALB/cJ mice a whole-body exposure to 0 (sham-controls) or 1.0 Gy of 100 MeV protons, delivered at 5 or 10 mGy min{sup -1}, the dose and dose rates found during solar particle events in space. As a reference radiation, groups of mice were exposed to 0 (sham-controls) or 1 Gy of {sup 137}Cs {gamma} rays (10 mGy min{sup -1}). After irradiation, BM cells were collected at 1.5, 3, 24 h, and 1 month for analyses (five mice per treatment group per harvest time). The results indicated that the in vivo time course of effects induced by a single dose of 1 Gy of 100 MeV protons or {sup 137}Cs {gamma} rays, delivered at 10 mGy min{sup -1}, was similar. Although statistically significant levels of NF-{kappa}B activation and pro-inflammatory cytokines in BM cells of exposed mice when compared to those in the corresponding sham controls (Student's t-test, p < 0.05 or < 0.01) were induced by either dose rate, these levels varied over time for each protein. Further, only a dose rate of 5 mGy min{sup -1} induced significant levels of anti-inflammatory cytokines. The results indicate dose-rate effects of protons.

  4. Prospective versus retrospective ECG-gated multislice CT coronary angiography: A systematic review of radiation dose and diagnostic accuracy

    International Nuclear Information System (INIS)

    Sun Zhonghua; Ng, Kwan-Hoong

    2012-01-01

    Purpose: To perform a systematic review of the radiation dose and diagnostic accuracy of prospective versus retrospective ECG-gated multislice CT coronary angiography. Materials and methods: A search of Pubmed/Medline and Sciencedirect databases for English literature was performed to identify studies comparing prospective and retrospective ECG-gated multislice CT angiography in the diagnosis of coronary artery disease. Effective dose, dose length product, image quality and diagnostic value were compared between two groups of studies. Results: 22 studies were included for analysis. The mean effective dose of prospective ECG-gated scans was 4.5 mSv (95% CI: 3.6, 5.3 mSv), which is significantly lower than that of retrospective scans, which is 13.8 mSv (95% CI: 11.5, 16.0 mSv) (p < 0.001). The mean dose length product was 225 mGy cm (95% CI: 188, 262 mGy cm) and 822 mGy cm (95% CI: 630, 1013 mGy cm) for the prospective and retrospective ECG-gated scans, respectively, indicating a statistically significant difference between these two protocols (p < 0.0001). The mean sensitivity and specificity of multislice CT angiography in the diagnosis of coronary artery disease was 97.7% (95% CI: 93.7%, 100%) and 92.1% (95% CI: 87.2%, 97%) for prospective ECG-gated scans; 95.2% (95% CI: 91%, 99.5%) and 94.4% (95% CI: 88.5%, 100%) for retrospective ECG-gated scans, respectively, with no significant difference for sensitivity but significant difference for specificity (p = 0.047). Conclusion: Multislice CT coronary angiography with prospective ECG-gating leads to a significant reduction of radiation dose when compared to that of retrospective ECG-gating, while offering comparable image quality and diagnostic value.

  5. Preliminary Diagnostic Reference Levels of Adult CT at Aristide Ledantec National Hospital

    International Nuclear Information System (INIS)

    Diagne, M.; Gning, F.; Dieng, M. M.; Gueye, L.

    2015-01-01

    The number of Computed Tomography (CT) procedures performed in Senegal has widely increased as the CT is a powerful tool for the accurate and effective diagnosis. CT is a diagnostic imaging modality giving higher patient dose in comparison with other radiological procedures. The establishing of diagnostic reference levels (DRLs) is a way to optimize the radiation arising from CT procedures to as low as reasonable (ALARA) and to ensure good practice. Objective: The purpose of this study is to establish Local Diagnostic Reference Levels (LDRLs) at the University Hospital of Aristide LeDantec for CT examinations and to compare these values with the international Diagnostic Reference Levels (DRLs) to benchmark the local practice. Materials/Methods: This was a cross-sectional survey carried out in HALD between August 2014 and January 2015. Demographic data and acquisition parameters of 700 CT scan examinations performed on adult patients were collected from request forms and CT scan consoles. The values of CTDIw, CTDIvol and DLP were calculated using ImPACT (Imaging Performance and Assessment of Computed Tomography) software for Siemens Definition AS scanner of HALD. This was done by correlating the measurements from the National Radiological Protection Board (NRPB–R250) scanners with the effective dose calculated, using the CT–EXPO software. Data was analyzed using mean, range, 3rd quartile, as well as mean. Frequency tables and histogrammes were used to summarise the data. Results: The 3rd quartile doses in this study for head, chest, abdomen and pelvis were 89 mGy, 12 mGy, 16.5 mGy, and 15 mGy, respectively. These values were in good agreement with the values reported from the literature. (author)

  6. Effect of Photon Hormesis on Dose Responses to Alpha Particles in Zebrafish Embryos

    Directory of Open Access Journals (Sweden)

    Candy Yuen Ping Ng

    2017-02-01

    Full Text Available Photon hormesis refers to the phenomenon where the biological effect of ionizing radiation with a high linear energy transfer (LET value is diminished by photons with a low LET value. The present paper studied the effect of photon hormesis from X-rays on dose responses to alpha particles using embryos of the zebrafish (Danio rerio as the in vivo vertebrate model. The toxicity of these ionizing radiations in the zebrafish embryos was assessed using the apoptotic counts at 20, 24, or 30 h post fertilization (hpf revealed through acridine orange (AO staining. For alpha-particle doses ≥ 4.4 mGy, the additional X-ray dose of 10 mGy significantly reduced the number of apoptotic cells at 24 hpf, which proved the presence of photon hormesis. Smaller alpha-particle doses might not have inflicted sufficient aggregate damages to trigger photon hormesis. The time gap T between the X-ray (10 mGy and alpha-particle (4.4 mGy exposures was also studied. Photon hormesis was present when T ≤ 30 min, but was absent when T = 60 min, at which time repair of damage induced by alpha particles would have completed to prevent their interactions with those induced by X-rays. Finally, the drop in the apoptotic counts at 24 hpf due to photon hormesis was explained by bringing the apoptotic events earlier to 20 hpf, which strongly supported the removal of aberrant cells through apoptosis as an underlying mechanism for photon hormesis.

  7. Estimation of the minimum dose required to measure ventricular width in follow-up cranial computed tomography (CCT) in children with hydrocephalus

    Energy Technology Data Exchange (ETDEWEB)

    Kirchhof, K. [Universitaetsklinikum Dresden (Germany). Inst. und Poliklinik fuer Radiologische Diagnostik; Wohlgemuth, W.A.; Berlis, A. [Klinikum Augsburg (Germany). Klinik fuer Diagnostische Radiologie und Neuroradiologie

    2010-12-15

    Purpose: To estimate the minimum dose needed at follow-up cranial computed tomography (CCT) to reliably determine ventricular width in children with hydrocephalus. Materials and Methods: For the study, a phantom was created using the calvarium of an infant which was filled with gelatin and the shaped inner cones of two carrots serving as lateral ventricles. The phantom was scanned ten times with two multi-slice CTs (LightSpeed Ultra, GE, and Somatom Sensation, Siemens), using a tube current of 400, 350, 300, 250, 200, 150, and 100 mA, and a tube voltage of 140, 120, 100, and 80 kV. The width of both lateral ventricles was measured at 4 sites. The values derived from scans performed at 380 / 400 mA and 140 kV (LightSpeed/Somatom) served as a reference. Measurements scored 1 point if they did not differ by more than 0.5 mm from the reference values. Results: The radiation dose can be reduced from 61.0 mGy to 9.2 mGy (15.1 %) with LightSpeed and from 55.0 mGy to 8.0 mGy (14.6 %) with Somatom without impairing the reliability of ventricular width measurements. However, in the case of both scanners, certain combinations of tube voltage and current yielded less reliable measurements although the dose was higher and the pixel noise was lower. Conclusion: There is no single cut-off dose or setting for tube voltage and current which guarantees reliable ventricular width measurements with the least radiation exposure for both scanners. As a guideline, it is safe to use the standard protocols with a reduced tube current of 100 kV. (orig.)

  8. Simulation of precipitation and strengthening in MG-RE alloys

    OpenAIRE

    Liu, Hong

    2017-01-01

    Magnesium - rare earth (Mg-RE) alloys have received considerable attention in the past decades for wider applications in the aerospace industry due to their relatively high strength and excellent creep resistance. Most rare-earth containing magnesium alloys, such as Mg-Y, Mg-Gd, and Mg-Y-Nd, are precipitation hardenable. A technical barrier to the wider applications of such alloys is the lack of a sufficiently large age hardening response. To further improve this response, an improved underst...

  9. Radiation exposure during paediatric CT in Sudan: CT dose, organ and effective doses

    International Nuclear Information System (INIS)

    Suliman, I.I.; Khamis, H.M.; Ombada, T.H.; Alzimami, K.; Alkhorayef, M.; Sulieman, A.

    2015-01-01

    The purpose of this study was to assess the magnitude of radiation exposure during paediatric CT in Sudanese hospitals. Doses were determined from CT acquisition parameters using CT-Expo 2.1 dosimetry software. Doses were evaluated for three patient ages (0-1, 1-5 and 5-10 y) and two common procedures (head and abdomen). For children aged 0-1 y, volume CT air kerma index (C vol ), air Kerma-length product and effective dose (E) values were 19.1 mGy, 265 mGy.cm and 3.1 mSv, respectively, at head CT and those at abdominal CT were 8.8 mGy, 242 mGy.cm and 7.7 mSv, respectively. Those for children aged 1-5 y were 22.5 mGy, 305 mGy.cm and 1.1 mSv, respectively, at head CT and 12.6 mGy, 317 mGy.cm, and 5.1 mSv, respectively, at abdominal CT. Dose values and variations were comparable with those reported in the literature. Organ equivalent doses vary from 7.5 to 11.6 mSv for testes, from 9.0 to 10.0 mSv for ovaries and from 11.1 to 14.3 mSv for uterus in abdominal CT. The results are useful for dose optimisation and derivation of national diagnostic reference levels. (authors)

  10. Estimation of the fetal dose by dose measurement during an irradiation of a parotid tumor; Estimation de la dose foetale par mesure de dose lors d'une irradiation d'une tumeur de la parotide

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, V.; Graff-Cailleaud, P.; Peiffert, D. [Centre Alexis-Vautrin, 54 - Vandoeuvre-les-Nancy (France); Noel, A. [Institut National Polytechnique de Lorraine, CRAN CNRS UMR-7039, 54 - Vandoeuvre-les-Nancy (France)

    2006-11-15

    The irradiation of a five months pregnant patient has been made for a right parotid attack. In conformation with the legislative texts relative to radiation protection ( publication 84 of the ICRP) an estimation of the dose received for the fetus has been led by dose measurement on phantom. With the dose limit ( 100 mGy) recommended in the publication 84 of the ICRP neither modification of the treatment nor abortion was necessary. (N.C.)

  11. Estimation of exposed radiation dose in radiography of the chest. Mainly on the dose at health examination on automobiles

    International Nuclear Information System (INIS)

    Suzuki, Shoichi; Oda, Akiko; Ohkura, Masaki

    1998-01-01

    The exposure doses in radiography and photofluorography of the chest at health examination on automobiles were estimated and compared with those using other hospital equipments. The tube voltage, effective energy and half value layer under ordinary conditions for radiography and fluorography were measured by KYOKKO model 100 X-ray analyzer and output pulse shape was confirmed by the fluorometer (TOREKEY-1001 C). The dose at the body surface was measured by the ionization chambers (VICTOREEN RADCON 500 and 30-330) which had been equipped in the WAC chest phantom (JIS Z 4915, Kyoto Kagaku). Nine automobiles of 3 facilities were used, of which X-ray generating apparatuses of either condenser or inverter type were manufactured by Hitachi (5 machines), Toshiba (1) and Shimadzu (3). The examined apparatuses not for the automobile were Toshiba-20 and Hitachi SIRIUS-100 portable ones and Hitachi DH-1520 TM high-voltage one. The effective energy was found dependent on the tube voltage (100-130 kV) and X-ray generating system (35.1-54.37 keV in the condenser type and 41.1-43.9 keV in the inverter type). Pulse shape analysis revealed that the pulse height and area under the pulse height-time curve were larger in the inverter system. The mean doses in photofluorography and radiography on automobiles were 0.525 and 0.297 mGy, respectively. The mean dose of 0.61 mGy in radiography at home with the portable apparatus was the highest even when compared with that of 0.525 mGy for fluorography on the automobile. Thus, the inverter system on the car can guarantee the level of 0.4 mGy defined by IAEA guideline (Safety series No. 115, 1996). (K.H.)

  12. Radiographic examination protocol and patient dose in lateral cephalometric radiography in Korea

    International Nuclear Information System (INIS)

    Choi, Jin Woo

    2010-01-01

    To survey the radiographic examination protocol for lateral cephalometric radiographic examinations and to measure their patient doses in Korea and to compare the dose according to the size of hospital, the type of image receptor system, and the installation duration. The radiographic examination protocols (kVp, mA, and exposure time) for lateral cephalometric radiography were surveyed with 61 cephalometric radiographic equipments and their patient dose-area product (DAP) measured with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for 51 cephalometric radiographic equipments. The radiographic examination protocols and patient doses were compared according to the size of hospital (university dental hospital, dental hospital, and dental clinic), the type of image receptor system (film-based, DR and CR type) and the installation duration, respectively. SPSS 12.0.1 for Windows (SPSS Inc., Chicago, USA) was used for independent t-test and ANOVA test. The average protocols were 77.0 kVp, 12.7 mA, 6.2 second for cephalometric radiography. The average patient dose (DAP) was 128.0 mGy cm2 and 3rd quartile dose (DAP) 161.1 mGy cm2 for cephalometric radiography for adult male. There was no statistically significant difference at average patient DAP according to the size of hospital, the type of image receptor system, and the installation duration, respectively. The average patient dose was 128.0 mGy cm2 and the third quartile patient dose 161.1 mGy cm2 for lateral cephalometric radiography for adult male in Korea.

  13. Radiation dose to infants, children and adults in X-ray diagnostic radiology-in the case of plain radiography

    International Nuclear Information System (INIS)

    Aoyama, Takahiko; Koyama, Shuji; Yamauchi-Kawaura, Chiyo; Sugimoto, Naruto; Fujii, Keisuke; Kawasaki, Toshio

    2012-01-01

    The objective of this study was to evaluate radiation doses to infant, child and adult patients undergoing various types of plain radiography and to compare the doses among them. The doses were measured using newborn, 6-year-child and adult anthropomorphic phantoms, in which photodiode dosimeters were implanted at various tissue and organ positions. Measured doses were used to evaluate organ and effective doses. Organ doses obtained in various types of radiography were lower than 0.7 mGy for adults, 0.3 mGy for children and 0.2 mGy for infants, excepting lens dose of approximately 1 mGy in adult head radiography, where the doses for children and infants lowered to 1/2-1/3 of the doses for adults. Effective doses in various types of head radiography for adults, children and infants were in identical levels in a range of 5-30 μSv. In chest, abdomen and hip-joint radiography, effective doses of 0.02-0.11 mSv for children and 0.02-0.08 mSv for infants were identical to or in a fraction of the doses for adults of 0.06-0.15 mSv. In adult head and spinal radiography, effective doses by International Commission of Radiological Protection (ICRP) Publication 60 lowered respectively to 1/6-1/9 and 1/3-1/9 of the doses listed in United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2000. (author)

  14. Effects of multiple low dose radiation on the apoptosis of splenocytes and immune factor in male diabetic rats

    International Nuclear Information System (INIS)

    Li Yanbo; Guo Caixia; Dong Lihua; Wang Jianfeng; Liu Shuchun; Lu Zhe; Gong Shouliang

    2009-01-01

    Objective: To explore the effect of multiple low dose radiation (LDR) on the apoptosis of splenocytes and immune factors in diabetes mellitus (DM) rats. Methods: The rats were randomly divided into control, DM and DM + LDR groups. The irradiation doses were 25, 50 and 75 mGy, and the irradiated times were 15. At the fourth weekend after the DM rats irradiated, the apoptotic rate and TCRαβ percentage of splenocytes were detected by flow cytometry, and the content of IL-2 in both serum and supernatant of cultured splenocytes were detected by ELISA. Results: Compared with that in the control, the body weight (BW) decreased in the DM and DM + LDR groups,particularly in DM group. The blood glucose (BG) level in the DM + LDR groups was higher than that in the control, but decreased significantly as compared with that in the DM group (P < 0.01). As compared with those in the control, the apoptotic rate in DM + 50 mGy (P < 0.05) and the content of serum IL-2 in DM + 75 mGy group (P < 0.01) all increased significantly, while the content of IL-2 in supernatant of cultured splenocytes decreased significantly in the DM + LDR groups. Compared with those in the DM group, the apoptotic rate and the percentage of TCRαβ in splenocytes in the DM + LDR groups (P < 0.01-P < 0.001) and the content of IL-2 in serum in DM + 50 mGy group (P < 0.01) decreased significantly. Conclusions: The multiple LDR could weaken the loss of BW and increase of BG caused by DM, decrease the splenocyte apoptosis induced by DM, and regulate the immune factors. (authors)

  15. Effect of low dose radiation on cell cycle and expression of its related proteins of HCT-8 cells

    International Nuclear Information System (INIS)

    Xu Ying; Ma Kewei; Li Wei; Wang Guanjun

    2009-01-01

    Objective: To study the effects of low dose radiation (LDR) on cell cycle and the expression of its related proteins of HCT-8 cells and provide theoretical basis for clinical application of LDR. Methods: Human colon carcinoma cells (HCT-8) cultivated in vitro were divided into seven groups: sham radiation group (0 mGy), LDR groups (25, 50, 75, 100 and 200 mGy) and high dose radiation group (1000 mGy). The proliferation rate was detected with the method of cell count and MTT, the ratios of G 0 /G 1 , S, G 2 /M in cell cycle were determined with flow cytometry after LDR, The cell cycle and expressions of related signal proteins were analyzed with protein assay system. Results: The results of cell count and MTT showed that there were no significant differences of proliferation rate of HCT-8 cells between 25, 50, 75, 100, 200 mGy LDR groups and sham radiation group (P>0.05); compared with high dose radiation group, there were significant differences (P 0 /G 1 phase of HCT-8 cells increased (P>0.05), the ratio of S phase decreased significantly (P 2 /M phase increased obviously (P 0 /G 1 , S, and G 2 /M phases of HCT-8 cells 48 h after radiation compared with sham radiation group (P>0.05). The protein assay result indicated that the expressions of AKt, PCNA, p27, CDK2, cyclin E, EGFR, ERK1/2, p-ERK, p-GSK-32/β in HCT-8 cells after LDR decreased compared with sham radiation group. Conclusion: LDR has no stimulating effect on HCT-8 cells. However, to some extent LDR suppress the expressions of some proteins related to proliferation and cell cycle. (authors)

  16. Absorbed dose to mice in prolonged irradiation by low-dose rate ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shiragai, Akihiro [National Inst. of Radiological Sciences, Chiba (Japan); Saitou, Mikio; Kudo, Iwao [and others

    2000-07-01

    In this paper, the dose absorbed by mice was evaluated as a preliminary study of the late effects of prolonged continuous irradiation of mice with low-dose rate ionizing radiation. Eight-week-old male and female SPF C3H/HeN mice in three irradiation rooms were exposed to irradiation at 8000, 400, and 20 mGy, respectively, using a {sup 137}Cs {gamma}-source. Nine racks were arranged in a circle approximately 2.5 m from the source in each room, and 10 cages were arranged on the 4 shelves of each rack. Dose distributions, such as in air at the source level, in the three rooms were estimated by using ionization chambers, and the absorbed dose distributions in the room and relative dose distributions in the cages in relation to the distance of the cage center were examined. The mean abdomen doses of the mice measured by TLD were compared with the absorbed doses in the cages. The absorbed dose distributions showed not only inverse-inverse-square-law behavior with distance from the source, but geometric symmetry in every room. The inherent scattering and absorption in each room are responsible for such behavior and asymmetry. Comparison of relative dose distributions revealed cage positions that are not suitable for experiments with high precision doses, but all positions can be used for prolonged continuous irradiation experiments if the position of the cages is rotated regularly. The mean abdomen doses of the mice were similar in each cage. The mean abdomen doses of the mice and the absorbed doses in a cage were almost the same in all cages. Except for errors concerning the positions of the racks and cages, the uncertainties in the exposure doses were estimated to be about {+-}12% for 8000 mGy group, 17% for 400 mGy group, and 35% for 20 mGy group. (K.H.)

  17. Radiation dose and cancer risk from pediatric CT examinations on 64-slice CT: A phantom study

    International Nuclear Information System (INIS)

    Feng Shiting; Law, Martin Wai-Ming; Huang Bingsheng; Ng, Sherry; Li Ziping; Meng Quanfei; Khong, Pek-Lan

    2010-01-01

    Objective: To measure the radiation dose from CT scans in an anthropomorphic phantom using a 64-slice MDCT, and to estimate the associated cancer risk. Materials and methods: Organ doses were measured with a 5-year-old phantom and thermoluminescent dosimeters. Four protocols; head CT, thorax CT, abdomen CT and pelvis CT were studied. Cancer risks, in the form of lifetime attributable risk (LAR) of cancer incidence, were estimated by linear extrapolation using the organ radiation doses and the LAR data. Results: The effective doses for head, thorax, abdomen and pelvis CT, were 0.7 mSv, 3.5 mSv, 3.0 mSv, 1.3 mSv respectively. The organs with the highest dose were; for head CT, salivary gland (22.33 mGy); for thorax CT, breast (7.89 mGy); for abdomen CT, colon (6.62 mGy); for pelvis CT, bladder (4.28 mGy). The corresponding LARs for boys and girls were 0.015-0.053% and 0.034-0.155% respectively. The organs with highest LARs were; for head CT, thyroid gland (0.003% for boys, 0.015% for girls); for thorax CT, lung for boys (0.014%) and breast for girls (0.069%); for abdomen CT, colon for boys (0.017%) and lung for girls (0.016%); for pelvis CT, bladder for both boys and girls (0.008%). Conclusion: The effective doses from these common pediatric CT examinations ranged from 0.7 mSv to 3.5 mSv and the associated lifetime cancer risks were found to be up to 0.16%, with some organs of higher radiosensitivity including breast, thyroid gland, colon and lungs.

  18. Radiation protection in CT pelvis in Fantoma Rando by thermoluminescent dosimetry.

    Science.gov (United States)

    Madrid-González, O A; Rivera-Montalvo, T; Azorín-Nieto, J

    2012-12-01

    This paper presents results of equivalent dose organ determining to both primary beam and scattered radiation in a computed tomography (CT) procedures. All measurements were carried out to abdomen and critical organ (gonads) area. Selected dosimeters showed a standard deviation of 4.1% below to the reference values established by international guide lines. The equivalent dose in gonads was 14.27 mGy. Copyright © 2012. Published by Elsevier Ltd.

  19. Radiation dose and cancer risk among pediatric patients undergoing interventional neuroradiology procedures

    International Nuclear Information System (INIS)

    Thierry-Chef, Isabelle; Simon, Steven L.; Miller, Donald L.

    2006-01-01

    During interventional neuroradiology procedures, patients can be exposed to moderate to high levels of radiation. Special considerations are required to protect children, who are generally more sensitive to the short- and long-term detrimental effects of radiation exposure. Estimates of dose to the skin of children from certain interventional procedures have been published elsewhere, but we are not aware of data on dose to the brain or on the long-term risk of cancer from brain radiation. Our goals were to estimate radiation doses to the brain in 50 pediatric patients who had undergone cerebral embolization and to assess their lifetime risks of developing radiation-related brain cancer. Entrance-peak skin dose and various assumptions on conditions of exposure were used as input for dosimetric calculations to estimate the spatial pattern of dose within the brain and the average dose to the whole brain for each child. The average dose and the age of the child at time of exposure were used to estimate the lifetime risk of developing radiation-related brain cancer. Among the 50 patients, average radiation doses to the brain were estimated to vary from 100 mGy to 1,300 mGy if exposed to non-collimated fields and from 20 mGy to 160 mGy for collimated, moving fields. The lifetime risk of developing brain cancer was estimated to be increased by 2% to 80% as a result of the exposure. Given the very small lifetime background risk of brain tumor, the excess number of cases will be small even though the relative increase might be as high as 80%. ALARA principles of collimation and dose optimization are the most effective means to minimize the risk of future radiation-related cancer. (orig.)

  20. Exposed dose comparison between coronary computed tomographic angiography and coronary angiography. Basic examination by phantom

    International Nuclear Information System (INIS)

    Kato, Kyoichi; Takahashi, Yoshimasa; Takahashi, Toshiyuki; Sai, Syogo; Fujimura, Kazumasa; Watanabe, Hiroyuki; Sato, Hisaya; Imai, Yasuhiro; Nakazawa, Yasuo

    2007-01-01

    The new type of coronary angiography (CAG) that uses 40 mm volumetric computed tomography (VCT) has great potential for cardiac disease. However, it is still necessary to be cognizant of exposure dose. We measured doses of CAG by both VCT and cardiovascular X-ray using a body phantom within 170 glass dosimeters. VCT protocols were 120 kV, 570 mA, and 0.35 sec/rot with and without the dose-reduction features (small cardiac X-ray beam filter and electrocardiogram (ECG) mA modulation). The cardiovascular X-ray protocol was Auto (65-77 kV) kV, Auto (41-46 mA) mA, 5 sec x 11 shots + 11 min fluoroscopy (minimum protocol for screening). VCT with and without the dose-reduction features has the same dose distribution, however, the dose-reduction features reduced the amount of dose by about 40-50%. For VCT with those features, measured dose was about 70 mGy in the cardiac area and 60 mGy at the skin of the back, whereas those of cardiovascular X-ray were 10 mGy and 30 mGy. We measured detailed dose distributions and variations in the phantom, and we also demonstrated the possibility of VCT's dose-reduction features. The CT dose was still higher than that of cardiovascular X-ray, however, there were advantages of CT scanning, for instance, information about calcification, soft plaque, and three-dimensional (3D) visualization. We think it is important to use both systems with an understanding of their advantages and limitations. (author)

  1. Effects of electron beam irradiation on inorganic exchanger AMP

    International Nuclear Information System (INIS)

    Rao, K.L.N.; Mathew, C.; Deshpande, R.S.; Jadhav, A.V.; Pande, B.M.; Shukla, J.P.

    1996-01-01

    The heteropolyacid salt inorganic exchanger ammonium molybdophosphate (AMP) was subjected to an electron dose upto 2 MGy to assess any possible radiation damage. The breakthrough and total exchange capacity of AMP for Cs + from simulated fission product solutions were determined for both control and irradiated samples. The scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) were deployed to examine any marked microscopic changes taking place in this exchanger. (author). 3 refs., 3 figs

  2. Dosimetric study of mandible examinations performed with three cone-beam computed tomography scanners.

    Science.gov (United States)

    Khoury, Helen J; Andrade, Marcos E; Araujo, Max Well; Brasileiro, Izabela V; Kramer, Richard; Huda, Amir

    2015-07-01

    The objective of this work was to evaluate the air kerma-area product (PKA) and the skin absorbed dose in the region of the eyes, salivary glands and thyroid of the patient from mandible examinations performed with three cone-beam computed tomography (CBCT) scanners, i.e. i-CAT classic, Gendex CB-500 and PreXion 3D. For the dosimetric evaluation, an anthropomorphic head phantom (model RS-250) was used to simulate an adult patient. The CBCT examinations were performed using standard and high-resolution protocols for mandible acquisitions for adult patients. During the phantom's exposure, the PKA was measured using an ionising chamber and the absorbed doses to the skin in the region of the eyes, thyroid and salivary glands were estimated using thermoluminescence dosemeters (TLDs) positioned on the phantom's surface. The PKA values estimated with the CBCT scanners varied from 26 to 138 µGy m(2). Skin absorbed doses in the region of the eyes varied from 0.07 to 0.34 mGy; at the parotid glands, from 1.31 to 5.93 mGy; at the submandibular glands, from 1.41 to 6.86 mGy; and at the thyroid, from 0.18 to 2.45 mGy. PKA and absorbed doses showed the highest values for the PreXion 3D scanner due to the use of the continuous exposure mode and a high current-time product. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Effects of γ and neutron irradiation on the optical absorption of pure silica core single-mode optical fibres from Nufern

    International Nuclear Information System (INIS)

    Calderon, A.; Martinez-Rivero, C.; Matorras, F.; Rodrigo, T.; Sobron, M.; Vila, I.; Virto, A.L.; Alberdi, J.; Arce, P.; Barcala, J.M.; Calvo, E.; Ferrando, A.; Josa, M.I.; Luque, J.M.; Molinero, A.; Navarrete, J.; Oller, J.C.; Valdivieso, P.; Yuste, C.; Fenyvesi, A.; Molnar, J.

    2006-01-01

    A measurement of the optical absorption, induced by photon irradiation up to a dose of 0.9 MGy, in Nufern silica core single-mode optical fibres is presented. In addition, the fibres were irradiated with neutrons, up to a total fluence of 2x10 14 cm -2 and the induced optical absorption was evaluated for four different wavelengths: 630, 670, 681 and 785 nm

  4. Average glandular dose in patients submitted to mammographic examinations

    International Nuclear Information System (INIS)

    Nogueira, M.S.; Silva, T.A. da; Oliveira, M. de; Joana, G.S.; Oliveira, A.L.K.

    2008-01-01

    Doses in mammography should be maintained as low as possible without reducing the high image quality needed to the early detection of the breast cancer. As the breast is composed of tissues with very soft composition and densities, it increases the difficulty to detect small changes in the normal anatomical structures that may be associated with breast cancer. To achieve the standards of resolution and contrast for mammography, the quality and intensity of the X-ray beam, the breast positioning and compression, the film screen system, and the film processing must be in optimal operational conditions. This study intended to evaluate the mean glandular dose of patients undergoing routine exams in one mammography unit. Patient image analyses were done by a radiologist doctor who took into account 10 evaluation criteria for each CC and MLO incidences. For estimating each patient glandular dose the radiographic technique parameters (kV and mAs) and the thickness of the compressed breast were recorded. European image quality criteria were adopted by the radiologist doctor to accept the image for diagnostic purpose. For breast densities of 50% adipose and 50% glandular tissues the incident air-kerma was measured and the glandular dose calculated considering the x-ray output during the exam. In the study of 50 patients the mean glandular dose varied from 0.90 to 3.27 mGy with a mean value of 1.98 mGy for CC incidences. For MLO incidences the mean glandular doses ranged from 0.97 to 3.98 mGy and a mean value of 2.60 mGy. (author)

  5. Multidetector computed tomography for the assessment of adnexal Mass: Is unenhenced CT scan necessary?

    International Nuclear Information System (INIS)

    Jung, Sung Il; Park, Hee Sun; Kim, Young Jun; Jeon, Hae Jeong

    2014-01-01

    To compare the diagnostic performance and radiation dose between contrast-enhanced CT (ECT) alone, and combined unenhanced and contrast-enhanced CT (UE + ECT) for the assessment of adnexal mass. This retrospective study was approved by the Institutional Review Board. A total of 146 consecutive patients (mean age, 41.1 years) who underwent preoperative unenhanced and contrast-enhanced multidetector CT of the pelvis and had adnexal masses found at surgery were included. Two readers independently evaluated the likelihood of adnexal malignancy on a 5-point scale on two different imaging datasets (ECT alone and UE + ECT). The area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic performance. Radiation dose to patients was calculated by the volume CT dose index (CTDIvol) and the dose length products (DLP) on each dataset. Of the total 178 adnexal masses, 133 masses were benign and 45 masses were malignant. For both readers, there is no significant difference of AUC values between ECT alone and UE + ECT for the detection of adnexal malignancy (reader 1, 0.93 vs. 0.95; reader 2, 0.92 vs. 0.91) (p > 0.05). The mean CTDIvol (12.6 ± 2.2 mGy) and DLP (641.2 ± 137.2 mGy) of ECT alone was significantly lower than the mean CTDIvol (21.5 ± 2.7 mGy) and DLP (923.6 ± 158.8 mGy) of UE + ECT (p < 0.0001). The use of unenhanced CT scan in addition to contrast-enhanced CT scan does not improve the detection of adnexal malignancy, but increases radiation exposure.

  6. DNA damage in lymphocytes induced by cardiac CT and comparison with physical exposure parameters

    Energy Technology Data Exchange (ETDEWEB)

    Fukumoto, Wataru; Tatsugami, Fuminari; Awai, Kazuo [Department of Diagnostic Radiology, Institute of Biomedical Health Sciences, Hiroshima University, Hiroshima (Japan); Ishida, Mari; Sakai, Chiemi [Institute of Biomedical and Health Sciences, Department of Cardiovascular Physiology and Medicine, Hiroshima University, Hiroshima (Japan); Tashiro, Satoshi [Hiroshima University, Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima (Japan); Ishida, Takafumi [Institute of Clinical Research West Medical Center, Hiroshima (Japan); Nakano, Yukiko [Hiroshima University Hospital, Department of Cardiovascular Medicine, Hiroshima (Japan)

    2017-04-15

    To investigate whether physical exposure parameters such as the dose index (CTDI), dose length product (DLP), and size-specific dose estimate (SSDE) are predictive of DNA damage. In vitro, we scanned a phantom containing blood samples from five volunteers at CTDI 50, 100, and 150 mGy. One sample was not scanned. We also scanned samples in three different-size phantoms at CTDI 100 mGy. In vivo, we enrolled 45 patients and obtained blood samples before and after cardiac CT. The γ-H2AX foci were counted. In vitro, in the control and at CTDI 50, 100, and 150 mGy, the number of γ-H2AX was 0.94 ± 0.24 (standard error, SE), 1.28 ± 0.30, 1.91 ± 0.47, and 2.16 ± 0.20. At SSDE 180, 156, and 135 mGy, it was 2.41 ± 0.20, 1.91 ± 0.47, and 1.42 ± 0.20 foci/cell. The γ-H2AX foci were positively correlated with the radiation dose and negatively correlated with the body size. In vivo, the γ-H2AX foci were significantly increased after CT (from 1.21 ± 0.19 to 1.92 ± 0.22 foci/cell) and correlated with CTDI, DLP, and SSDE. DNA damage was induced by cardiac CT. There was a correlation between the physical exposure parameters and γ-H2AX. (orig.)

  7. Evaluation of the dental status and identification of factors influencing oral health for the purpose of the periodontal disease prophylaxis in dogs

    OpenAIRE

    Vilimaitė, Ilona

    2016-01-01

    The objective of this research was to evaluate dental status and identify oral health influencing factors for the purpose of periodontal disease prophylaxis in dogs. The research took place between March 2015 - October 2015 at LSMU Dr. Leono Kriauceliuno smalll animal clinic and other, named “X”, “Y”, “Z”. Measures used in research: questionnaire, examination protocol, dental plaque disclosing solution „REVEAL“. The dogs dental status in dogs was examined visually, by OHI, QHT, MRCI, MGI indi...

  8. Phytoplankton-Environmental Interactions in Reservoirs. Volume I. Papers Presented at Workshop, 10-12 April 1979, Monterey, California.

    Science.gov (United States)

    1981-09-01

    Antarctic waters. Symp. Antarctic Oceanography. Santiago , Chile . Eppley, R.W. 1972. Temperature and phytoplankton growth in the sea. Fish. Bull. 70:1063...photorespiration is largely dependent on the partial pressure of car- bon dioxide and oxygen concentrations . When CO2 limits photosynthesis and oxygen...hardness and alkalinity concentrations (> 200 mg/i as CaCO 3). As CO2 is removed from the alkalinity _ystem, pH increases and most alkalinity is

  9. A cohort study of thyroid disease in relation to fallout from nuclear weapons testing

    International Nuclear Information System (INIS)

    Kerber, R.A.; Till, J.E.; Simon, S.L.; Lyon, J.L.; Thomas, D.C.; Preston-Martin, S.; Rallison, M.L.; Lloyd, R.D.; Stevens, W.

    1993-01-01

    OBJECTIVE--To estimate individual radiation doses and current thyroid disease status for a previously identified cohort of 4818 schoolchildren potentially exposed to fallout from detonations of nuclear devices at the Nevada Test Site between 1951 and 1958. DESIGN--Cohort analytic study. SETTING--Communities in southwestern Utah, southeastern Nevada, and southeastern Arizona. PARTICIPANTS--Individuals who were still residing in the three-state area (n = 3122) were reexamined in 1985 and 1986, and information on the subjects' and their mothers' milk and vegetable consumption during the fallout period was obtained by telephone interview (n = 3545). After exclusions to eliminate missing data and confounding factors, 2473 subjects were available for analysis. MAIN OUTCOME MEASURES--Individual radiation doses to the thyroid were estimated by combining consumption data with radionuclide deposition rates provided by the US Department of Energy and a survey of milk producers. Relative risk models adjusted for age, sex, and state were fitted using maximum likelihood to period prevalence data for thyroid carcinomas, neoplasms, and nodules. RESULTS--Doses ranged from 0 mGy to 4600 mGy, and averaged 170 mGy in Utah. There was a statistically significant excess of thyroid neoplasms (benign and malignant; n = 19), with an increase in excess relative risk of 0.7% per milligray. A relative risk for thyroid neoplasms of 3.4 was observed among 169 subjects exposed to doses greater than 400 mGy. Positive but nonsignificant dose-response slopes were found for carcinomas and nodules. CONCLUSIONS--Exposure to Nevada Test Site-generated radioiodines was associated with an excess of thyroid neoplasms. The conclusions are limited by the small number of exposed individuals and the low incidence of thyroid neoplasms

  10. Defect chemistry, thermomechanical and transport properties of (RE2 - xSrx)0.98(Fe0.8Co0.2)1 - yMgyO4 - δ (RE = La, Pr)

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Schönbeck, C.; Hagen, Anke

    2013-01-01

    The oxygen nonstoichiometry of Ruddlesden-Popper compounds with chemical composition (RE2 - xSrx)0.98(Fe 0.8Co0.2)1 - yMgyO 4 - δ (RE = La, Pr, x = 0.9-1.2 and y = 0, 0.2) was measured as a function of temperature and oxygen activity (aO2) by coulometric titration and thermogravimetry. All...

  11. Pediatric patient doses in interventional cardiology procedures

    International Nuclear Information System (INIS)

    Medeiros, R.B.; Murata, C.H.; Moreira, A.C.

    2014-01-01

    The radiation doses from interventional procedures is relevant when treating children because of their greater radiosensitivity compared with adults. The purposes of this paper were to estimate the dose received by 18 pediatric patients who underwent cardiac interventional procedures and to correlate the maximum entrance surface air kerma (Ke,max), estimated with radiochromic films, with the cumulative air kerma values displayed at the end of procedures. This study was performed in children up to 6 years. The study was performed in two hospitals, one located in Recife and the other one in São Paulo. The x-ray imaging systems used were Phillips Allura 12 model with image intensifier system and a Phillips Allura FD10 flat panel system. To estimate the Ke,max on the patient’s skin radiochromic films(Gafchromic XR-RV2) were used. These values were estimated from the maximum optical density measured on film using a calibration curve. The results showed cumulative air kerma values ranging from 78.3- 500.0mGy, with a mean value of 242,3 mGy. The resulting Ke,max values ranged from 20.0-461.8 mGy, with a mean value of 208,8 mGy. The Ke,max values were correlated with the displayed cumulative air kerma values. The correlation factor R² was 0.78, meaning that the value displayed in the equipment’s console can be useful for monitoring the skin absorbed dose throughout the procedure. The routine fluoroscopy time records is not able by itself alert the physician about the risk of dose exceeding the threshold of adverse reactions, which can vary from an early erythema to serious harmful skin damage. (author)

  12. Radionuclides and the birds at Ravenglass

    International Nuclear Information System (INIS)

    Lowe, V.P.W.

    1991-01-01

    Since 1983 concern has been expressed about the apparent decline in numbers of birds in the Ravenglass estuary in west Cumbria, particularly of the black-headed gull colony on the Drigg dunes, and suggestions have been made that this decline might be due to excessive radiation in the birds' food and their general environment. Twelve species of marine invertebrates from Ravenglass, known to be important foods for birds, were analysed, and further samples were taken from sites along the west Cumbrian coast. None of these samples showed excessive contamination with any of the radionuclides analysed. Analysis of a sample of bird carcasses from the area showed oystercatchers (Haematopus ostralegus) and shelduck (Tadorna tadorna) to have some of the highest concentrations of 137 Cs in their tissues; yet their breeding success and populations were not affected. Black-headed gulls were found to be feeding mainly inland, and were the least contaminated with radionuclides of all the birds at Ravenglass, yet this species and its breeding success were in decline. Calculations of the total dose equivalent rate to the whole body of the most contaminated black-headed gull amounted to 9.8 x 10 -4 mSv h -1 (∼ 8.4 x 10 -4 mGy h -1 , whole-body absorbed dose rate), and the background exposure dose was of the order of 8.3 x 10 -4 mGy h -1 . As a minimum chronic dose of 1000 mGy day -1 has been found necessary to retard growth of nestling birds, and 9600 mGy over 20 days of incubation to cause the death of 50% of embryos in black-headed gulls' eggs, the concentrations of radionuclides in the foods, body tissues and general environment were at least three orders of magnitude too low to have had any effects. (author)

  13. Positive enteric contrast material for abdominal and pelvic CT with automatic exposure control: What is the effect on patient radiation exposure?

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhen J., E-mail: jane.wang@radiology.ucsf.edu [Department of Radiology, University of California San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143-0628 (United States); Chen, Katherine S.; Gould, Robert; Coakley, Fergus V.; Fu Yanjun; Yeh, Benjamin M. [Department of Radiology, University of California San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143-0628 (United States)

    2011-08-15

    Objective: To assess the effect of positive enteric contrast administration on automatic exposure control (AEC) CT radiation exposure in (1) a CT phantom, and (2) a retrospective review of patients. Materials and methods: We scanned a CT phantom containing simulated bowel that was sequentially filled with water and positive enteric contrast, and recorded the mean volume CT dose index (CTDIvol). We also identified 17 patients who had undergone 2 technically comparable CT scans of the abdomen and pelvis, one with positive enteric contrast and the other with oral water. Paired Student's t-tests were used to compare the mean CT