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In this work, thermoluminescent dosimeters have been used to measure entrance surface doses (ESDs) of patients undergoing mammographic screening at the University College Hospital, Ibadan, Oyo state. The mean glandular doses (MGDs) were also calculated using the measured ESDs. The results showed that the ESDs ranged from 0.26mGy to 21.26mGy for the mediolateral oblique (MLO) views and 0.08mGy to 5.36mGy for the craniocaudal (CC) views. The calculated MGD ranged from 0.07mGy to 3.57mGy for the MLO views and 0.02mGy to 0.98mGy for the CC views. The possible reasons for the large variations in the individual ESD values and MGD values for both views are discussed using patients data, equipment specific data and the technical parameters used for the examinations. Comparison showed that the mean...

International Nuclear Information System (INIS)

In this work, thermoluminescent dosimeters have been used to measure entrance surface doses (ESDs) of patients undergoing mammographic screening at the University College Hospital, Ibadan, Oyo state. The mean glandular doses (MGDs) were also calculated using the measured ESDs. The results showed that the ESDs ranged from 0.26 mGy to 21.26 mGy for the mediolateral oblique (MLO) views and 0.08 mGy to 5.36 mGy for the craniocaudal (CC) views. The calculated MGD ranged from 0.07 mGy to 3.57 mGy for the MLO views and 0.02 mGy to 0.98 mGy for the CC views. The possible reasons for the large variations in the individual ESD values and MGD values for both views are discussed using patients' data, equipment specific data and the technical parameters used for the examinations. Comparison showed that the mean ESD values and MGD ...

International Nuclear Information System (INIS)

In 16 female patients wick colpourethrocystography was performed directly successively with large-size films as well as medium-size films (intensifier fluorography). The area exposure products were measured by a dosemeter closely attached to the diaphragm and separately for radiography and fluorography, resp. Surface doses as well as organ doses were calculated according to Rosenstein. The average radiatin doses of the active bone marrow were 6.03 mGy for examination with large-size films and 1.27 mGy for fluorography; the average gonadal doses were 7.45 mGy and 1.56 mGy, resp. The portion of fluoroscopy in radiation exposure amounted to 14.8% in large-size film examination, but was 74.0% in medium-size examination. Thus the comparative results revealed a significant reduction of the patient's radiation dose by application of intensifier fluorography in colpourethrocystography.

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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 ...

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Overview  Package   Class  Use  Tree  Deprecated  Index  Help   PREV CLASS   NEXT CLASS FRAMES    NO FRAMES SUMMARY:  INNER | FIELD | CONSTR | METHOD DETAIL:  FIELD | CONSTR | METHOD gov.nih.nci.dc.bean Class ImageIDParseBean java.lang.Object | +--java.util.Dictionary

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Several Mg-Y binary ribbons with Y content up to #approx#17.9 at.% were fabricated by melt-spinning. X-ray diffraction (XRD) revealed that the phase structure changes with increasing Y content from extended solid solution to partially amorphous, and then fully intermetallic Mg_2_4Y_5. Anodic potentiodynamic polarization performed in 0.01 M NaCl electrolyte (pH=12) revealed improved anodic passivity behavior compared to pure Mg for all the Mg-Y alloys. X-ray photoelectron spectroscopy (XPS) revealed that the improved passivity of Mg-Y was more related to the elemental oxidation state rather than the concentration of the surface components. To study the effect of Cl"- ion on the passivity behavior, anodic potentiodynamic and potentiostatic polarization were performed on Mg-17.9 at.% Y in alkaline (pH=12) NaCl electrolytes containing Cl"- ion in the concentration range from 0.00 to 0.50 M. The passive films formed in 0.01 M ...

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A number of diagnostic X-ray units in Poland were subjected to analysis. The air kerma on X-ray tables was measured for the X-ray parameters used routinely during lumbo-sacral spine radiography of standard adult patient. Measurements of air kerma were performed using TLD made of lithium-fluoride. The doses received by patients in different X-ray departments can differ more than two orders of magnitude (from 0.42 mGy up to 72.11 mGy), for the same X-ray examination. The dose can be significantly reduced if fluorescent screens made from components of rare earth are used. (author). 10 refs, 1 fig., 2 tabs.

British Library Electronic Table of Contents (United Kingdom)

Zusammenfassung Hintergrund Endograftimplantationen im oder am Aortenbogen stellen besondere Herausforderungen an die Implantationstechnik und an die mechanischen Eigenschaften von Stentgrafts und ihren Einf?hrungssystemen, bedingt durch die Notwendigkeit, die Prothesen punktgenau abzusetzen und durch die mit der Biegung im Aortenbogen zunehmende Reibungswiderst?nde innerhalb der Einf?hrungssysteme. Die Endograftsysteme der 1. Generation (Talent?, Zenith TX 1?, TAG?) zeigten in dieser Lokalisation technisch bedingte Limitationen. Neue Prothesen Bei den seit 2004 und 2005 verf?gbaren neuen Stentgrafts (E-vita?, Zenith TX 2?, Valiant?, Relay?) sind diese Limitationen weitgehend ?berwunden. Durch technische Verbesserungen von Stentgrafts und Einf?hrungssystemen ist es nun m?glich, auch lange ...

Energy Technology Data Exchange (ETDEWEB)

Mechanical ventilation in private homes was for many years a stepchild of air conditioning engineers. A decisive impulse for change came in January 1995 with the enactment of the new Thermal Insulation Ordinance which for the first time allows house owners to exceed the usual admissible annual heating requirement by a certain amount on the condition that they equip the house with mechanical ventilation systems. (orig.) [Deutsch] Ueber lange Jahre war die mechanische Wohnungslueftung ein Stiefkind der Raumlufttechnik. Einen entscheidenden Impuls gab erst die seit Januar 1995 gueltige Waermeschutzverordnung, die erstmals zulaesst, dass ein gewisses Quantum des Jahres-Heizwaermebedarfs durch den Einbau mechanischer Wohnungslueftungen kompensiert werden kann. (orig.)

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Objective: To investigate the relationship between exposure dose and image quality for a direct digital radiography system and to determine the optimum exposure parameters for pelvic examination. Methods: A contrast-detail phantom CDRAD2.0 was exposed to different doses and the IQF of phantom images were calculated. The optimum exposure parameters were determined by ANOVA and SNK analysis. The image of an anthropomorphic phantom taken with optimized exposure parameters was verified using CEC image criteria. Results: The IQF of the images of CDRAD2.0 phantom was significantly different for different doses, as the exposure dose was greater than 0.61 mGy. The IQFs have no difference for different dose groups. The image quality between this optimized exposure dose and conventional exposure dose not was significantly different. Conclusion: The image quality of direct digital radiography system is improved as the exposure dose increases, and as the exposure dose exceeds ...

Energy Technology Data Exchange (ETDEWEB)

Apoptosis is a pattern of cell death involving nuclear pycnosis, cytoplasmic condensation, and karyorrhexis. Apoptosis induced by continuous irradiation with gamma rays (externally given by a 137Cs source) or with beta rays (from tritiated water injected ip) was quantified in the crypts of two portions of mouse bowel, the small intestine and descending colon. The time-course change in the incidence of apoptosis after each type of radiation could be explained on the basis of the innate circadian rhythm of the cells susceptible to apoptotic death and of the excretion of tritiated water (HTO) from the body. For 6-h continuous gamma irradiation at various dose rates (0.6-480 mGy/h) and for 6 h after injection of HTO of various radioactivities (0.15-150 GBq per kg body wt), the relationships between dose and incidence of apoptosis were obtained. Survival curves were then constructed from the curves for dose vs incidence of apoptosis. For the calculation of the absorbed dose from HTO, the ...

International Nuclear Information System (INIS)

Objective: To investigate the X-ray radiation dose patients dealt with the hepatic intervention. Methods: Thermoluminescence and tissue-equivalent anthropomorphic phantom were used to measure the X-ray radiation dose in patients dealt with the hepatic intervention in 85 patients. Results: The peak skin dose in the patients who accepted hepatic intervention was from 179.95 to 1759.00 mGy, effective dose approached 29.22 mSv (male), 29.27 mSv (female). Conclusion: Hepatic intervention is now regarded as an important therapeutic method for liver cancer. However, the patients were exposed to too much X-ray radiation during interventional procedures. Some more effective protection should be taken to decrease the X-ray radiation dose accepted by patients. (authors)

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An overview is given of several computer models in use in the Netherlands to determine and analyze the quality of air and the effect of air pollution abatement measures. [Dutch] Voor het vaststellen van de luchtkwaliteit of het bepalen van het effect van emissiereducerende maatregelen op die luchtkwaliteit zijn in ons land meerdere computermodellen beschikbaar. In het kader van het Vooronderzoek Innovatieprogramma Luchtkwaliteit (VIPL) wilde het ministerie van Verkeer en Waterstaat meer inzicht in de betrouwbaarheid en specifieke eigenschappen van deze modellen. Deze studie geeft daarom een overzicht en analyse van de verschillen, overeenkomsten en voor- en nadelen van de meest gangbare Nederlandse computermodellen om de luchtkwaliteit rond snelwegen te bepalen. Dit zijn: Het Voorspellingssysteem Luchtkwaliteit Wegtraces (VLW); CAR-II; Het TNO-verkeersmodel; Het Heaven-model van TNO; Urbis (air); en NNM+ (KEMA-STACKS)

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In areas where radiation dose monitoring has not been performed, it is essential to use material available in the environment be able to rapidly assess doses to individuals for immediate emergency medical care or for general estimation of the radiological consequences. It was shown that certain types of telephone cards containing microchips have the potential to be used as individual radiation dosimeters in emergency situations to detect doses over 250 mGy by luminescence measurements. In order to understand the dosimetric properties of chip cards, the components obtained from INFINIEON Company at various stages of production were used for luminescence measurements. It is found that the protecting layer used above the chips so called 'globe top' is the main source of radiation induced signal in chip cards. The globe top produced by INFINIEON at that stage is found to contain SiO2 and Epoxy. In order to improve the dosimetric properties of the chip cards, the raw ...

International Nuclear Information System (INIS)

Conditions for radiation induced grafting with butyl acrylate dispersed in water emulsion onto chrome-tanned pig skins have been worked out for #gamma#-rays and electron beam irradiations. The highest yield of grafting was observed at monomer concentration approximately 25% (w/w), dose equal to 25 kGy and dose rate not exceeding 10 MGy/h. At these conditions the yield of grafting attained a value approximately 25% and content of homopolymer in the leather amounted to 6%. The efficiency of monomer to polymer conversion decreases when the concentration of monomer in emulsion and dose rate increases. Yield of homopolymer is independent of the dose rate. An explanation of the observed relations has been proposed. The physical and used properties of grafted leathers were tested. Radiation processed leathers were found superior to samples finished by traditional methods. One has to point to better tolerance against chemical cleaning and reduced water take-up without loss ...

International Nuclear Information System (INIS)

The effects of various antioxidants and antioxidant concentrations on the radiation and thermal stability of EPDM and XLPE polymers used for insulation of electric cable in nuclear power plants were measured. The objective was to determine if particular antioxidants could be identified as being especially effective for stabilization against radiation aging and combined thermal and radiation aging. Elongation to rupture was used as the measure of stability. Materials were irradiated to doses up to 2 MGy (200 Mrad) at a dose rate of 200 to 300 Gy/h in the Cobalt-60 Gamma Irradiation Facility at the University of Virginia. All of the antioxidants tested, which were known to provide excellent thermal stability, also provided good stability for radiation aging and combined thermal/radiation aging, although small differences between antioxidants were noted. No antioxidant or antioxidant combination was identified as being especially outstanding. Stabilization against ...

Energy Technology Data Exchange (ETDEWEB)

The ECOTEC combustion system and the architecture of the new Opel 2.2 l aluminum engine have been configured to achieve low noise and exhaust emissions. This power unit, employed in Germany for the first time in the Astra Coupe, already complies with the Euro IV emissions standard. It features minimum maintenance requirements and a long operating life. The DOHC spark-ignition engine with four valves per cylinder has two chain-driven camshafts, valve gear with roller cam followers and hydraulic lash adjusters. Two chain driven balancer shafts have been integrated into the engine block. The cylinder head and block, lower crankcase, oil pan, and cylinder head cover are all made of aluminum. A modular concept makes it possible to adapt the engine effectively to different vehicle concepts and markets. (orig.) [German] Das ECOTEC-Verbrennungssystem und die Motorarchitektur des neuen 2,2-l-Aluminium-Triebwerks von Opel sind auf niedrige Geraeusch- und Abgasemissionen ausgelegt. Das in ...

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Magnetic resonance imaging (MRI) of the lung is challenging because of substantial drawbacks. However, lung pathologies that are associated with increased attenuation values in CT enhance visualization in MRI: proton density is increased and tissue-air interfaces, resulting in susceptibility artifacts, are reduced in pneumonia, pneumonitis, edema, and carcinoma. On the other hand, many lung diseases result in shortness of breath, so that patients cannot hold their breath for long periods. Therefore, fast imaging techniques are required which should also allow for high spatial resolution so that small lesions can be detected. Calcifications and air pockets within lesions are not readily recognized with MRI. Thin section CT is standard for the diagnosis of pneumonia. With parallel imaging techniques, MRI examination of the lungs can be performed with short periods of breath holding, which allow for sub-centimeter resolution in the z-axis. Especially for follow-up examinations in ...

International Nuclear Information System (INIS)

Metabolic profile is an important biological marker of neoplastic processes not only in the tumor itself but also in the host organism. The neuro-hormone melatonin has been implicated in the experiments as an oncostatic agent. Female Wistar:Han SPF rats (Velaz, Prague, Czech Republic) were irradiated continuously for 15 days using a daily gamma rays dose of 96 mGy. At the end of exposure one group of rats was administered 5 mg/kg b.w. of dimethylbenz/a/anthracene (DMBA) intragastrically. During the period of exposure to ionizing radiation a part of the animals was supplied with melatonin (M) at a concentration of 20 #mu#l/ml in drinking water. Selected parameters of lipid and carbohydrate metabolism and levels of selected hormones were determined 2, 30 and 100 days post-irradiation. The irradiation itself caused only small changes in tissue lipids. The application of a single low dose (subthreshold from the point of view of induction of mammary tumors) of DMBA ...

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The research carried out in Canada in the design of containers for the disposal of radioactive waste has focussed on spent nuclear fuel, even though the quantities of other currently stored radioactive wastes are substantially greater. Research carried out at the Royal Military College of Canada on the effects of mixed fields of radiation on high polymer adhesives and composite materials has shown that some polymers are quite resistant to radiation and could well serve in the fabrication of radioactive waste disposal containers. The purpose of this research was to determine if thermoplastic polymers could be used as superior materials to replace metals in the application of low and intermediate level radioactive waste disposal containers. Polymers have the advantage that they do not corrode like metals. The experimental methods, used in this research, focused on the effects of radiation on the properties of the materials. Polypropylene, Nylon 66, Polycarbonate, and Polyurethane, with ...

Energy Technology Data Exchange (ETDEWEB)

The main conclusion of the study on the title subject is that the impacts of climatic change in the Netherlands are still limited. However, the impacts will be stronger in the next decades and will be even problematic at the end of this century. In this book an overview is given of probable changes in the climate for the Netherlands, danger for flooding in specific areas of the Netherlands, changes of the nature, impacts for agriculture, tourism and recreation, and industry and businesses, and risks for public health. [Dutch] De effecten van klimaatverandering in Nederland zijn nu nog beperkt. Ze zullen echter de komende decennia toenemen, maar pas tegen het eind van deze eeuw problematisch worden. Dat is de hoofdboodschap van de titelstudie. De studie is opgesteld in samenwerking met een reeks instellingen, die zijn verenigd in het Platform Communicatie Klimaatverandering (PCCC). Het klimaat verandert: de zeespiegel stijgt, de afvoeren van de rivieren nemen toe. De natuur reageert al ...

International Nuclear Information System (INIS)

The objective of this study was to explore the role of three-dimensional (3-D) rotational angiography (RA) of the inferior vena cava (IVC; 3-D CV) before filter retrieval and its impact on treatment planning compared with standard anteroposterior cavography (sCV). Thirty patients underwent sCV and 3-D CV before IVC filter retrieval. Parameters assessed were: projection of filter arms or legs beyond the caval lumen, thrombus burden within the filter and IVC, and orientation of the filter within IVC. Skin and effective radiation doses were calculated. Statistical analysis was performed using paired Student t test and nonparametric McNemar's test. Standard anteroposterior cavography detected 49 filter arms or legs projecting beyond the caval lumen in 25 patients. Three-dimensional CV demonstrated 89 filter arms or legs projecting beyond the caval lumen in 28 patients. Twenty-two patients had additional filter arms or legs projecting beyond the caval lumen detected on 3-D CV that were not ...