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Sample records for water phantom cooperative

  1. Neutron dosimetry in solid water phantom

    Energy Technology Data Exchange (ETDEWEB)

    Benites-Rengifo, Jorge Luis, E-mail: jlbenitesr@prodigy.net.mx [Centro Estatal de Cancerologia de Nayarit, Calzada de la Cruz 118 Sur, Tepic Nayarit, Mexico and Instituto Tecnico Superior de Radiologia, ITEC, Calle Leon 129, Tepic Nayarit (Mexico); Vega-Carrillo, Hector Rene, E-mail: fermineutron@yahoo.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. postal 336, 98000, Zacatecas, Zac. (Mexico)

    2014-11-07

    The neutron spectra, the Kerma and the absorbed dose due to neutrons were estimated along the incoming beam in a solid water phantom. Calculations were carried out with the MCNP5 code, where the bunker, the phantom and the model of the15 MV LINAC head were modeled. As the incoming beam goes into the phantom the neutron spectrum is modified and the dosimetric values are reduced.

  2. Validation of Cooper's ligament thickness in software breast phantoms

    Science.gov (United States)

    Kuperavage, Adam J.; Imran, Abdullah-Al-Zubaer; Bakic, Predrag R.; Maidment, Andrew; Pokrajac, David D.

    2017-03-01

    Anthropomorphic breast phantoms are important tools for a wide range of tasks including pre-clinical validation of novel imaging techniques. In order to improve the realism in the phantoms, assessment of simulated anatomical structures is crucial. Thickness of simulated Cooper's ligaments influences the percentage of dense tissue, as well as qualitative and quantitative properties of simulated images. We introduce three methods (2-dimensional watershed, 3-dimensional watershed, and facet counting) to assess the thickness of the simulated Cooper's ligaments in the breast phantoms. For the validation of simulated phantoms, the thickness of ligaments has been measured and compared with the input thickness values. These included a total of 64 phantoms with nominal ligament thicknesses of 200, 400, 600, and 800 μm. The 2-dimensional and 3-dimensional watershed transformations were performed to obtain the median skeleton of the ligaments. In the 2-dimensional watershed, the median skeleton was found cross-section by cross-section, while the skeleton was found for the entire 3-dimensional space in the 3-dimensional watershed. The thickness was calculated by taking the ratio of the total volume of ligaments and the volume of median skeleton. In the facet counting method, the ligament thickness was estimated as a ratio between estimated ligaments' volume and average ligaments' surface area. We demonstrated that the 2-dimensional watershed technique overestimates the ligament thickness. Good agreement was found between the facet counting technique and the 3-dimensional watershed for assessing thickness. The proposed techniques are applicable for ligaments' thickness estimation on clinical breast images, provided segmentation of Cooper's ligaments has been performed.

  3. Water equivalent phantom materials for 192Ir brachytherapy

    Science.gov (United States)

    Schoenfeld, Andreas A.; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor

    2015-12-01

    Several solid phantom materials have been tested regarding their suitability as water substitutes for dosimetric measurements in brachytherapy with 192Ir as a typical high energy photon emitter. The radial variations of the spectral photon fluence, of the total, primary and scattered photon fluence and of the absorbed dose to water in the transversal plane of the tested cylindrical phantoms surrounding a centric and coaxially arranged Varian GammaMed afterloading 192Ir brachytherapy source were Monte-Carlo simulated in EGSnrc. The degree of water equivalence of a phantom material was evaluated by comparing the radial dose-to-water profile in the phantom material with that in water. The phantom size was varied over a large range since it influences the dose contribution by scattered photons with energies diminished by single and multiple Compton scattering. Phantom axis distances up to 10 cm were considered as clinically relevant. Scattered photons with energies reaching down into the 25 keV region dominate the photon fluence at source distances exceeding 3.5 cm. The tested phantom materials showed significant differences in the degree of water equivalence. In phantoms with radii up to 10 cm, RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR phantoms show excellent water equivalence with dose deviations from a water phantom not exceeding 0.8%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene show deviations up to 2.6%. For larger phantom radii up to 30 cm, the deviations for RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR remain below 1.4%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene produce deviations up to 8.1%. PMMA plays a separate role, with deviations up to 4.3% for radii not exceeding 10 cm, but below 1% for radii up to 30 cm. As suggested by

  4. Local Water Conflict and Cooperation

    DEFF Research Database (Denmark)

    Hermann, Roberto Rivas; Hooper, Catherine; Munk Ravnborg, Helle

    2011-01-01

    In 2007 the Danish Institute for International Studies (DIIS) launched the research programme “Competing for Water: Understanding conflict and cooperation in local water governance”. Along with partners in five developing countries (Bolivia, Mali, Nicaragua, Vietnam and Zambia), the programme aims...... to contribute to “sustainable local water governance in support of the rural poor and otherwise disadvantaged groups in developing countries by improving the knowledge among researchers and practitioners of the nature, extent and intensity of local water conflict and cooperation and their social, economic...... and political impacts, and how this may change with increased competition for water” (DIIS 2007). The country research teams developed an overview of the national water governance frameworks at an early stage of the Competing for Water programme period (Bustamante and Cossio, 2007; Djiré et al., 2007; Gómez et...

  5. Local Water Conflict and Cooperation

    DEFF Research Database (Denmark)

    Hermann, Roberto Rivas; Hooper, Catherine; Munk Ravnborg, Helle

    2011-01-01

    to contribute to “sustainable local water governance in support of the rural poor and otherwise disadvantaged groups in developing countries by improving the knowledge among researchers and practitioners of the nature, extent and intensity of local water conflict and cooperation and their social, economic......In 2007 the Danish Institute for International Studies (DIIS) launched the research programme “Competing for Water: Understanding conflict and cooperation in local water governance”. Along with partners in five developing countries (Bolivia, Mali, Nicaragua, Vietnam and Zambia), the programme aims...... and political impacts, and how this may change with increased competition for water” (DIIS 2007). The country research teams developed an overview of the national water governance frameworks at an early stage of the Competing for Water programme period (Bustamante and Cossio, 2007; Djiré et al., 2007; Gómez et...

  6. International cooperation in water resources

    Science.gov (United States)

    Jones, J.R.; Beall, R.M.; Giusti, E.V.

    1979-01-01

    Advancements in hydrology proceeded slowly until the late 1800's when new ventures created a surge of interest and accomplishment. Progress waned again until the middle 20th century when an International Hydrological Decade was conceived, eventually receiving wide multinational support from governmental agencies and nongovernmental institutions. Organized by UNESCO, the Decade program was launched January 1, 1965. Participation included 107 nations, six United Nations agencies, and more than a dozen international scientific organizations. The initial program emphasized scientific research, and international cooperation; the second half of the Decade, emphasized technical assistance and technology transfer, largerly through education, training and demonstration. The success of the Decade led to the establishment of the International Hydrological Program, again under the aegis of UNESCO, to continue the work of the Decade indefinitely. The five major program activities, now involving about 90 countries and several international organizations, include: the scientific program, the promotion of education and training, the enhancement of information exchange, support of technical assistance, and the enlargement of regional cooperation. A significant amount of activity related to hydrological data networks and forecasting is carried on in an Operational Hydrology Programme by the WMO, chiefly through its Commission for Hydrology. Other international governmental organizations with a strong interest in water include the UN, the UN Development Programme, the FAO, the WHO, the International Atomic Energy Agency, the UN Environment Programme, the International Standardization Organization, and developmental institutions such as the World Bank. The specialized interests of researchers outside of the governmental structure, are met through association in various scientific and technical organizations which are world wide in scope and membership. Notwithstanding a sometimes

  7. Factors for converting dose measured in polystyrene phantoms to dose reported in water phantoms for incident proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Moyers, M. F.; Vatnitsky, A. S.; Vatnitsky, S. M. [Loma Linda University Medical Center, Loma Linda, California 92354 (United States); Guthrie Clinic/Robert Packard Hospital, Sayre, Pennsylvania 18840 (United States); EBG MedAustron, Wiener Neustadt, Austria A2700 (Austria)

    2011-10-15

    Purpose: Previous dosimetry protocols allowed calibrations of proton beamline dose monitors to be performed in plastic phantoms. Nevertheless, dose determinations were referenced to absorbed dose-to-muscle or absorbed dose-to-water. The IAEA Code of Practice TRS 398 recommended that dose calibrations be performed with ionization chambers only in water phantoms because plastic-to-water dose conversion factors were not available with sufficient accuracy at the time of its writing. These factors are necessary, however, to evaluate the difference in doses delivered to patients if switching from calibration in plastic to a protocol that only allows calibration in water. Methods: This work measured polystyrene-to-water dose conversion factors for this purpose. Uncertainties in the results due to temperature, geometry, and chamber effects were minimized by using special experimental set-up procedures. The measurements were validated by Monte Carlo simulations. Results: At the peak of non-range-modulated beams, measured polystyrene-to-water factors ranged from 1.015 to 1.024 for beams with ranges from 36 to 315 mm. For beams with the same ranges and medium sized modulations, the factors ranged from 1.005 to 1.019. The measured results were used to generate tables of polystyrene-to-water dose conversion factors. Conclusions: The dose conversion factors can be used at clinical proton facilities to support beamline and patient specific dose per monitor unit calibrations performed in polystyrene phantoms.

  8. Development and clinical application of a length-adjustable water phantom for total body irradiation.

    Science.gov (United States)

    Chen, Zhi-Wei; Yao, Sheng-Yu; Zhang, Tie-Ning; Zhu, Zhen-Hua; Hu, Zhe-Kai; Lu, Xun

    2012-08-01

    A new type of water phantom which would be specialised for the absorbed dose measurement in total body irradiation (TBI) treatment is developed. Ten millimetres of thick Plexiglas plates were arranged to form a square cube with 300 mm of edge length. An appropriate sleeve-type piston was installed on the side wall, and a tabular Plexiglas piston was positioned inside the sleeve. By pushing and pulling the piston, the length of the self-made water phantom could be varied to meet the required patients' physical sizes. To compare the international standard water phantom with the length-adjustable and the Plexiglas phantoms, absorbed dose for 6-MV X ray was measured by an ionisation chamber at different depths in three kinds of phantoms. In 70 cases with TBI, midplane doses were metered using the length-adjustable and the Plexiglas phantoms for simulating human dimensions, and dose validation was synchronously carried out. There were no significant statistical differences, p > 0.05, through statistical processing of data from the international standard water phantom and the self-designed one. There were significant statistical differences, p body width. Obviously, the difference had a positive correlation with the body width. The results proved that the new length-adjustable water phantom is more accurate for simulating human dimensions than Plexiglas phantom.

  9. Water equivalence of some plastic-water phantom materials for clinical proton beam dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sulaiti, L., E-mail: l.al-sulaiti@surrey.ac.uk [Physics Department, University of Surrey, Guildford (United Kingdom); Radiation Dosimetry Team, National Physical Laboratory, Teddington (United Kingdom); Shipley, D.; Thomas, R. [Radiation Dosimetry Team, National Physical Laboratory, Teddington (United Kingdom); Owen, P. [Physics Department, University of Surrey, Guildford (United Kingdom); Radiation Dosimetry Team, National Physical Laboratory, Teddington (United Kingdom); Kacperek, A. [Douglas Cyclotron, Clatterbridge Centre for Oncology, Wirral (United Kingdom); Regan, P.H. [Physics Department, University of Surrey, Guildford (United Kingdom); Palmans, H. [Radiation Dosimetry Team, National Physical Laboratory, Teddington (United Kingdom)

    2012-07-15

    Plastic-water phantom materials are not exactly water equivalent since they have a different elemental composition and different interaction cross sections for protons than water. Several studies of the water equivalence of plastic-water phantom materials have been reported for photon and electron beams, but none for clinical proton beams. In proton beams, the difference between non-elastic nuclear interactions in plastic-water phantom materials compared to those in water should be considered. In this work, the water equivalence of Plastic Water{sup Registered-Sign} (PW){sup 1}, Plastic Water{sup Registered-Sign} Diagnostic Therapy (PWDT){sup 1} and solid water (WT1){sup 2} phantoms was studied for clinical proton energies of 60 MeV and 200 MeV. This was done by evaluating the fluence correction factor at equivalent depths; first with respect to water and then with respect to graphite by experiment and Monte Carlo (MC) simulations using FLUKA. MC simulations showed that the fluence correction with respect to water was less than 0.5% up to the entire penetration depth of the protons at 60 MeV and less than 1% at 200 MeV up to 20 cm depth for PWDT, PW and WT1. With respect to graphite the fluence correction was about 0.5% for 60 MeV and about 4% for 200 MeV. The experimental results for modulated and un-modulated 60 MeV proton beams showed good agreement with the MC simulated fluence correction factors with respect to graphite deviating less than 1% from unity for the three plastic-water phantoms. - Highlights: Black-Right-Pointing-Pointer We study plastic-water in clinical proton beams by experiment and Monte Carlo. Black-Right-Pointing-Pointer We obtain fluence correction factors for water and graphite. Black-Right-Pointing-Pointer The correction factor for water was close to 1 at 60 MeV and <0.990 at 200 MeV. Black-Right-Pointing-Pointer The correction factor for graphite was {approx}0.5% at 60 MeV and up to 4% at 200 MeV.

  10. Monte Carlo modeling of 60 Co HDR brachytherapy source in water and in different solid water phantom materials

    Directory of Open Access Journals (Sweden)

    Sahoo S

    2010-01-01

    Full Text Available The reference medium for brachytherapy dose measurements is water. Accuracy of dose measurements of brachytherapy sources is critically dependent on precise measurement of the source-detector distance. A solid phantom can be precisely machined and hence source-detector distances can be accurately determined. In the present study, four different solid phantom materials such as polymethylmethacrylate (PMMA, polystyrene, Solid Water, and RW1 are modeled using the Monte Carlo methods to investigate the influence of phantom material on dose rate distributions of the new model of BEBIG 60 Co brachytherapy source. The calculated dose rate constant is 1.086 ± 0.06% cGy h−1 U−1 for water, PMMA, polystyrene, Solid Water, and RW1. The investigation suggests that the phantom materials RW1 and Solid Water represent water-equivalent up to 20 cm from the source. PMMA and polystyrene are water-equivalent up to 10 cm and 15 cm from the source, respectively, as the differences in the dose data obtained in these phantom materials are not significantly different from the corresponding data obtained in liquid water phantom. At a radial distance of 20 cm from the source, polystyrene overestimates the dose by 3% and PMMA underestimates it by about 8% when compared to the corresponding data obtained in water phantom.

  11. Water splitting by cooperative catalysis

    NARCIS (Netherlands)

    D.G.H. Hetterscheid; J.I. van der Vlugt; B. de Bruin; J.N.H. Reek

    2009-01-01

    A mononuclear Ru complex is shown to efficiently split water into H2 and O2 in consecutive steps through a heat- and light-driven process (see picture). Thermally driven H2 formation involves the aid of a non-innocent ligand scaffold, while dioxygen is generated by initial photochemically induced re

  12. Absorbed dose to water reference dosimetry using solid phantoms in the context of absorbed-dose protocols.

    Science.gov (United States)

    Seuntjens, Jan; Olivares, Marina; Evans, Michael; Podgorsak, Ervin

    2005-09-01

    For reasons of phantom material reproducibility, the absorbed dose protocols of the American Association of Physicists in Medicine (AAPM) (TG-51) and the International Atomic Energy Agency (IAEA) (TRS-398) have made the use of liquid water as a phantom material for reference dosimetry mandatory. In this work we provide a formal framework for the measurement of absorbed dose to water using ionization chambers calibrated in terms of absorbed dose to water but irradiated in solid phantoms. Such a framework is useful when there is a desire to put dose measurements using solid phantoms on an absolute basis. Putting solid phantom measurements on an absolute basis has distinct advantages in verification measurements and quality assurance. We introduce a phantom dose conversion factor that converts a measurement made in a solid phantom and analyzed using an absorbed dose calibration protocol into absorbed dose to water under reference conditions. We provide techniques to measure and calculate the dose transfer from solid phantom to water. For an Exradin A12 ionization chamber, we measured and calculated the phantom dose conversion factor for six Solid Water phantoms and for a single Lucite phantom for photon energies between 60Co and 18 MV photons. For Solid Water of certified grade, the difference between measured and calculated factors varied between 0.0% and 0.7% with the average dose conversion factor being low by 0.4% compared with the calculation whereas for Lucite, the agreement was within 0.2% for the one phantom examined. The composition of commercial plastic phantoms and their homogeneity may not always be reproducible and consistent with assumed composition. By comparing measured and calculated phantom conversion factors, our work provides methods to verify the consistency of a given plastic for the purpose of clinical reference dosimetry.

  13. Water content contribution in calculus phantom ablation during Q-switched Tm:YAG laser lithotripsy.

    Science.gov (United States)

    Zhang, Jian J; Rajabhandharaks, Danop; Xuan, Jason Rongwei; Wang, Hui; Chia, Ray W J; Hasenberg, Tom; Kang, Hyun Wook

    2015-01-01

    Q-switched (QS) Tm:YAG laser ablation mechanisms on urinary calculi are still unclear to researchers. Here, dependence of water content in calculus phantom on calculus ablation performance was investigated. White gypsum cement was used as a calculus phantom model. The calculus phantoms were ablated by a total 3-J laser pulse exposure (20 mJ, 100 Hz, 1.5 s) and contact mode with N=15 sample size. Ablation volume was obtained on average 0.079, 0.122, and 0.391  mm3 in dry calculus in air, wet calculus in air, and wet calculus in-water groups, respectively. There were three proposed ablation mechanisms that could explain the effect of water content in calculus phantom on calculus ablation performance, including shock wave due to laser pulse injection and bubble collapse, spallation, and microexplosion. Increased absorption coefficient of wet calculus can cause stronger spallation process compared with that caused by dry calculus; as a result, higher calculus ablation was observed in both wet calculus in air and wet calculus in water. The test result also indicates that the shock waves generated by short laser pulse under the in-water condition have great impact on the ablation volume by Tm:YAG QS laser.

  14. Neutron fluence depth profiles in water phantom on epithermal beam of LVR-15 research reactor.

    Science.gov (United States)

    Viererbl, L; Klupak, V; Lahodova, Z; Marek, M; Burian, J

    2010-01-01

    Horizontal channel with epithermal neutron beam at the LVR-15 research reactor is used mainly for boron neutron capture therapy. Neutron fluence depth profiles in a water phantom characterise beam properties. The neutron fluence (approximated by reaction rates) depth profiles were measured with six different types of activation detectors. The profiles were determined for thermal, epithermal and fast neutrons.

  15. Effect of the Scattering Radiation in Air and Two Type of Slap Phantom between PMMA and the ISO Water Phantom for Personal Dosimeters Calibration

    Science.gov (United States)

    Kamwang, N.; Rungseesumran, T.; Saengchantr, D.; Monthonwattana, S.; Pungkun, V.

    2017-06-01

    The calibration of personal dosimeter to determine the quantities of the personal dose equivalent, Hp(d), is required to be placed on a suitable phantom in order to provide a reasonable approximation to the radiation backscattering properties as equivalent as part of body. The dosimeter which is worn on the trunk usually calibrated with slap phantom which recommended in ICRU 47 with dimension of 30 cm (w) x 30 cm (h) x 15 cm (t) PMMA slab phantom to achieve uniformity in calibration procedures, on the other hand the International Organization for Standardization (ISO), ISO 4037-3, proposed the ISO water slap phantom, with PMMA walls, same dimension but different wall thickness (front wall 2.5 mm and other side wall 10 mm thick) and fill with water. However, some laboratories are still calibrating a personal dosimeter in air in term of ambient dose equivalent, H*(d). This research study the effect of the scattering radiation in two type of those slap phantoms and in air, to calibrate two type of OSL (XA and LA) and electronic personal dosimeters. The X-ray and Cs-137 radiation field with the energy range from 33 to 662 keV were used. The results of this study will be discussed.

  16. Three-dimensional radiochromic film dosimetry for volumetric modulated arc therapy using a spiral water phantom.

    Science.gov (United States)

    Tanooka, Masao; Doi, Hiroshi; Miura, Hideharu; Inoue, Hiroyuki; Niwa, Yasue; Takada, Yasuhiro; Fujiwara, Masayuki; Sakai, Toshiyuki; Sakamoto, Kiyoshi; Kamikonya, Norihiko; Hirota, Shozo

    2013-11-01

    We validated 3D radiochromic film dosimetry for volumetric modulated arc therapy (VMAT) using a newly developed spiral water phantom. The phantom consists of a main body and an insert box, each of which has an acrylic wall thickness of 3 mm and is filled with water. The insert box includes a spiral film box used for dose-distribution measurement, and a film holder for positioning a radiochromic film. The film holder has two parallel walls whose facing inner surfaces are equipped with spiral grooves in a mirrored configuration. The film is inserted into the spiral grooves by its side edges and runs along them to be positioned on a spiral plane. Dose calculation was performed by applying clinical VMAT plans to the spiral water phantom using a commercial Monte Carlo-based treatment-planning system, Monaco, whereas dose was measured by delivering the VMAT beams to the phantom. The calculated dose distributions were resampled on the spiral plane, and the dose distributions recorded on the film were scanned. Comparisons between the calculated and measured dose distributions yielded an average gamma-index pass rate of 87.0% (range, 91.2-84.6%) in nine prostate VMAT plans under 3 mm/3% criteria with a dose-calculation grid size of 2 mm. The pass rates were increased beyond 90% (average, 91.1%; range, 90.1-92.0%) when the dose-calculation grid size was decreased to 1 mm. We have confirmed that 3D radiochromic film dosimetry using the spiral water phantom is a simple and cost-effective approach to VMAT dose verification.

  17. Calibration of ionization chambers in IAEA water phantom; Kalibrering av ionekamre i IAEA-vannfantom

    Energy Technology Data Exchange (ETDEWEB)

    Bjerke, H.; Mikkelborg, O.

    1995-11-01

    The calibration in a water phantom is realised at the Secondary Standard Dosimetry Laboratory in Norway. The method is valid for chambers used in high energy radiation therapy. The method, setup and corrections in the calibration are described. The absorbed dose to air calibration factor, N{sub D}, will have an uncertainty of {approx}0.8% (k=1). 15 refs., 7 figs., 5 tabs.

  18. Radiation detectors exactly positioned in water phantoms; Strahlungsdetektoren exakt in Wasserphantomen positioniert.

    Energy Technology Data Exchange (ETDEWEB)

    Makowski, Christoph [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany). Arbeitsgruppe ' Hochenergetische Photonen- und Elektronenstrahlung'

    2013-06-15

    Radiation detectors applied in the medical field must at the producer or later on in the hospital be periodically calibrated with water phantoms. The treatment success depends hereby decidingly on the quality of the dosimetry. Both the contact point of the water surface and the distance to the detector or otherwise the alignment of the probe on the beam axis must be determined as precisely as possible. For this important problem the PTB offers now a measurement system, which comprehends for the first time objective and simultaneously precise results.

  19. Cooperative water network system to reduce carbon footprint.

    Science.gov (United States)

    Lim, Seong-Rin; Park, Jong Moon

    2008-08-15

    Much effort has been made in reducing the carbon footprint to mitigate climate change. However, water network synthesis has been focused on reducing the consumption and cost of freshwater within each industrial plant. The objective of this study is to illustrate the necessity of the cooperation of industrial plants to reduce the total carbon footprint of their water supply systems. A mathematical optimization model to minimize global warming potentials is developed to synthesize (1) a cooperative water network system (WNS) integrated over two plants and (2) an individual WNS consisting of two WNSs separated for each plant. The cooperative WNS is compared to the individual WNS. The cooperation reduces their carbon footprint and is economically feasible and profitable. A strategy for implementing the cooperation is suggested for the fair distribution of costs and benefits. As a consequence, industrial plants should cooperate with their neighbor plants to further reduce the carbon footprint.

  20. Production of a faithful realistic phantom to human head and thermal neutron flux measurement on the brain surface. Cooperative research

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Kazuyoshi; Kumada, Hiroaki; Kishi, Toshiaki; Torii, Yoshiya; Uchiyama, Junzo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Endo, Kiyoshi; Yamamoto, Tetsuya; Matsumura, Akira; Nose, Tadao [Tsukuba Univ., Tsukuba, Ibaraki (Japan)

    2002-12-01

    Thermal neutron flux is determined using the gold wires in current BNCT irradiation, so evaluation of arbitrary points after the irradiation is limited in the quantity of these detectors. In order to make up for the weakness, dose estimation of a patient is simulated by a computational dose calculation supporting system. In another way without computer simulation, a medical irradiation condition can be replicate experimentally using of realistic phantom which was produced from CT images by rapid prototyping technique. This phantom was irradiated at a same JRR-4 neutron beam as clinical irradiation condition of the patient and the thermal neutron distribution on the brain surface was measured in detail. This experimental evaluation technique using a realistic phantom is applicable to in vitro cell irradiation experiments for radiation biological effects as well as in-phantom experiments for dosimetry under the nearly medical irradiation condition of patient. (author)

  1. Production of a faithful realistic phantom to human head and thermal neutron flux measurement on the brain surface. Cooperative research

    CERN Document Server

    Yamamoto, K; Kishi, T; Kumada, H; Matsumura, A; Nose, T; Torii, Y; Uchiyama, J; Yamamoto, T

    2002-01-01

    Thermal neutron flux is determined using the gold wires in current BNCT irradiation, so evaluation of arbitrary points after the irradiation is limited in the quantity of these detectors. In order to make up for the weakness, dose estimation of a patient is simulated by a computational dose calculation supporting system. In another way without computer simulation, a medical irradiation condition can be replicate experimentally using of realistic phantom which was produced from CT images by rapid prototyping technique. This phantom was irradiated at a same JRR-4 neutron beam as clinical irradiation condition of the patient and the thermal neutron distribution on the brain surface was measured in detail. This experimental evaluation technique using a realistic phantom is applicable to in vitro cell irradiation experiments for radiation biological effects as well as in-phantom experiments for dosimetry under the nearly medical irradiation condition of patient.

  2. Imaging of primary and secondary radiation-Modelling and experimental results of a radioactive source and a water phantom

    Science.gov (United States)

    Gamage, K. A. A.; Taylor, G. C.; Joyce, M. J.

    2014-11-01

    In this paper the contribution of primary and secondary radiation from a water phantom to a pinhole volume, as a result of three neutron sources (Cf, AmBe and 5 MeV mono-energetic) and two gamma sources (Cs and Co), is separately estimated using the PTRAC particle tracking option available in MCNP. Also in this paper imaging of the mixed radiation field produced by a Van de Graaf accelerator (when a water phantom is present) is described. In the model, a spherical tally volume, 2 cm in diameter, was placed equidistantly from a radioactive source and 30×30×15 cm3 water phantom. Monte Carlo simulations have been carried out to investigate the level of primary and secondary radiation contributing to the pinhole volume directly from the source and from interactions in the phantom respectively. The spatial distribution of counts clearly discriminated the source and the phantom. The results have shown that the percentage of neutrons reflected from the phantom with energies above 1 MeV increases with mean energy of the source. This method has significant potential to characterise secondary radiation in proton therapy, where it would help to verify the location and the energy delivered during the treatment.

  3. Dosimetric study of thermoluminescent detectors in clinical photon beams using liquid water and PMMA phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, Luciana C., E-mail: lmatsushima@ipen.br [Gerencia de Metrologia das Radiacoes (GMR) - Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, CEP: 05508-000, Sao Paulo, SP (Brazil); Veneziani, Glauco R. [Gerencia de Metrologia das Radiacoes (GMR) - Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, CEP: 05508-000, Sao Paulo, SP (Brazil); Sakuraba, Roberto K. [Gerencia de Metrologia das Radiacoes (GMR) - Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, CEP: 05508-000, Sao Paulo, SP (Brazil); Sociedade Beneficente Israelita Brasileira - Hospital Albert Einstein (HAE), Avenida Albert Einstein, 665, Morumbi, CEP: 05652-000, Sao Paulo, SP (Brazil); Cruz, Jose C. da [Sociedade Beneficente Israelita Brasileira - Hospital Albert Einstein (HAE), Avenida Albert Einstein, 665, Morumbi, CEP: 05652-000, Sao Paulo, SP (Brazil)

    2012-07-15

    The purpose of this study was the dosimetric evaluation of thermoluminescent detectors of calcium sulphate doped with dysprosium (CaSO{sub 4}:Dy) produced by IPEN compared to the TL response of lithium fluoride doped with magnesium and titanium (LiF:Mg,Ti) dosimeters and microdosimeters produced by Harshaw Chemical Company to clinical photon beams dosimetry (6 and 15 MV) using liquid water and PMMA phantoms. - Highlights: Black-Right-Pointing-Pointer Dosimetric study of thermoluminescent detectors of CaSO{sub 4}:Dy, LiF:Mg,Ti and {mu}LiF:Mg,Ti. Black-Right-Pointing-Pointer Clinical (6 and 15 MV) photon beams dosimetry using liquid water and PMMA phantom. Black-Right-Pointing-Pointer Linear behavior to the dose range (0.1 to 5 Gy). Black-Right-Pointing-Pointer TL response reproducibility better than {+-}4.34%. Black-Right-Pointing-Pointer CaSO{sub 4}:Dy represent a cheaper alternative to the TLD-100.

  4. Application of Stochastic Cooperative Games in Water Resources

    OpenAIRE

    Zara, Stefano; Patrone, Fioravante; Moretti, Stefano; Dinar, Ariel

    2006-01-01

    Traditionally, cooperative game theory has been applied to a variety of water resource problems assuming a deterministic pattern of supply. On the other hand, in view of the important role that water plays in regional and local projects, and taking into account that with climate change affecting the water cycle, the world is expected to face more stochastic and extreme events of water supply, incorporating stochastic consideration of water supply becomes more acute in designing water faciliti...

  5. Israel,China to Strengthen Water Technology Cooperation

    Institute of Scientific and Technical Information of China (English)

    Hu Wenxiu

    2011-01-01

    @@ To turn desert into oasis is the top priority of the water-poor Israel.The country has made miraculous achievements in turning arid land into fertile agricultural farmland.Now Israel hopes to strengthen cooperation with China in water resources and technology and jointly meet the global water challenge.

  6. Dosimetry Comparison of Water Phantom and Complete Eye Definition for 125I and 103Pd Brachytherapy Plaques

    Directory of Open Access Journals (Sweden)

    Zohreh Dehghannia Rostami

    2011-06-01

    Full Text Available Introduction: In this paper, by complete definition of human eye containing the various parts and their materials, the difference between this model and a homogeneous water phantom are compared for two ophthalmic plaques using 125I and 103Pd. Material and methods: The simulation of the two phantoms were performed in the MCNP-4C code and by using the geometry of a three-dimensional eye, different parts of the eye including the lens, cornea, retina, choroid, sclera, anterior chamber, optic nerve and tumor were defined in the eye phantom. Also, for two ophthalmic brachytherapy sources, 20 mm COMS plaques containing 24 125I or 103Pd sources were simulated. The depth dose and doses in different parts of the eye were calculated by using the *F8 tally in the MCNP code. Results: The results showed that the doses in different parts of the eye in the two phantoms were different and depended on the ophthalmic plaques. The dose increased in the tumor and decreased in some parts of the eye such as the lens. Discussion and Conclusion: Complete definition of human eye in simulation of ophthalmic brachytherapy leads to better results. As the effects of eye definition are different in the tumor and healthy tissues, the results for the eye phantom provide more accurate information for calculation of treatment time and the type of ophthalmic brachytherapy used.

  7. A novel method to obtain modulus image of soft tissues using ultrasound water jet indentation: a phantom study.

    Science.gov (United States)

    Lu, Min-Hua; Zheng, Yong-Ping; Huang, Qing-Hua

    2007-01-01

    The alteration of tissue stiffness is generally known to be associated with pathological changes. Ultrasound indentation is one of the methods that can be used to assess the mechanical properties of the soft tissues. It uses a flat-ended ultrasound transducer to directly contact the tissue to sense tissue deformation under an applied load. This paper introduced a novel noncontact ultrasound indentation system using water jet compression. The key idea was to utilize a water jet as the indenter as well as the coupling medium for propagation of the ultrasound beam. High frequency focused ultrasound (20 MHz) was used to measure the indentation deformation at a microscopic level. It has been demonstrated that the system could effectively assess the tissue-mimic phantoms with different stiffness. Water jet coupling allows the system to conduct C-scan on soft tissues rapidly and conveniently. By applying different pressures while taking C-scan sequences, the modulus images of the phantoms could be obtained based on the applied pressure and the phantom deformation and thickness. This paper presented the preliminary results on gel phantoms. The spatial resolution, the contrast resolution of the measurements and the reproducibility of the results were also discussed.

  8. Regulation of AQP0 water permeability is enhanced by cooperativity.

    Science.gov (United States)

    Németh-Cahalan, Karin L; Clemens, Daniel M; Hall, James E

    2013-03-01

    Aquaporin 0 (AQP0), essential for lens clarity, is a tetrameric protein composed of four identical monomers, each of which has its own water pore. The water permeability of AQP0 expressed in Xenopus laevis oocytes can be approximately doubled by changes in calcium concentration or pH. Although each monomer pore functions as a water channel, under certain conditions the pores act cooperatively. In other words, the tetramer is the functional unit. In this paper, we show that changes in external pH and calcium can induce an increase in water permeability that exhibits either a positive cooperativity switch-like increase in water permeability or an increase in water permeability in which each monomer acts independently and additively. Because the concentrations of calcium and hydrogen ions increase toward the center of the lens, a concentration signal could trigger a regulatory change in AQP0 water permeability. It thus seems plausible that the cooperative modes of water permeability regulation by AQP0 tetramers mediated by decreased pH and elevated calcium are the physiologically important ones in the living lens.

  9. Water Reallocation - Increasing Opportunities for Cooperation, Administration and Market

    Science.gov (United States)

    Cai, X.; Marston, L.

    2016-12-01

    Nowadays utilizable water in many regions around the world has been allocated among the various users. Increasing demands and limited water supplies necessitates water reallocation given that the existing allocation is economically inefficient, socially unfair, and environmentally unsustainable. Water reallocation, a dynamic adaptation strategy to changing socioeconomic and environmental conditions, offers a flexible water management approach to mitigate water scarcity under changing socioeconomic, climatic, and environmental conditions. Water reallocation can be implemented via collective cooperation, administration, and/or market-based approaches. In spite of the numerous benefits of reallocating water between users, examples of successful water transfers are relatively sparse and the expected benefits are rarely met in full due to several complex impediments. This study discusses the key barriers to wider implementation of water reallocation based on overview of the current body of water reallocation literature. Many examples of water transfers from around the world illustrate both the benefits and challenges associated with reallocation. To overcome the obstacles for more effective reallocation, we propose an interdisciplinary approach to water reallocation that couples developments in the natural sciences and engineering disciplines with current water reallocation scholarship, which is predominately rooted in the social sciences. We conclude by calling for an integrated research platform that focuses on supporting both voluntary and nonvoluntary forms of water reallocation; however, a greater emphasis should be on nonmarket means of water transfer since it is more feasible for many regions where water rights are not well defined and institutional capacity is insufficient.

  10. Phantom Pain

    Science.gov (United States)

    ... is still there. This painless phenomenon, known as phantom limb sensation, may rarely occur in people who were born without limbs. Phantom limb sensations may include feelings of coldness, warmth, or ...

  11. Transboundary Water Resources in Southern Africa: Conflict or cooperation?

    CSIR Research Space (South Africa)

    Patrick, MJ

    2006-01-01

    Full Text Available to explain why states might choose cooperation over conflict where a critical shared resource could limit future development potential. KEYWORDS hydropolitical complex; water wars; southern African development community; river basin management... the management of the various transboundary river basins that form the hydrological foundation of the SADC economy. This observation is remarkable given the known history of intense conflict that was as- sociated with the ColdWar-era in southern Africa...

  12. Phantom Pain

    NARCIS (Netherlands)

    Wolff, Andre; Vanduynhoven, Eric; van Kleef, Maarten; Huygen, Frank; Pope, Jason E.; Mekhail, Nagy

    2011-01-01

    Phantom pain is pain caused by elimination or interruption of sensory nerve impulses by destroying or injuring the sensory nerve fibers after amputation or deafferentation. The reported incidence of phantom limb pain after trauma, injury or peripheral vascular diseases is 60% to 80%. Over half the p

  13. Calculating Error Percentage in Using Water Phantom Instead of Soft Tissue Concerning 103Pd Brachytherapy Source Distribution via Monte Carlo Method

    Directory of Open Access Journals (Sweden)

    OL Ahmadi

    2015-12-01

    Full Text Available Introduction: 103Pd is a low energy source, which is used in brachytherapy. According to the standards of American Association of Physicists in Medicine, dosimetric parameters determination of brachytherapy sources before the clinical application was considered significantly important. Therfore, the present study aimed to compare the dosimetric parameters of the target source using the water phantom and soft tissue. Methods: According to the TG-43U1 protocol, the dosimetric parameters were compared around the 103Pd source in regard with water phantom with the density of 0.998 gr/cm3 and the soft tissue with the density of 1.04 gr/cm3 on the longitudinal and transverse axes using the MCNP4C code and the relative differences were compared between the both conditions. Results: The simulation results indicated that the dosimetric parameters depended on the radial dose function and the anisotropy function in the application of the water phantom instead of soft tissue up to a distance of 1.5 cm,  between which a good consistency was observed. With increasing the distance, the difference increased, so as within 6 cm from the source, this difference increased to 4%. Conclusions: The results of  the soft tissue phantom compared with those of the water phantom indicated 4% relative difference at a distance of 6 cm from the source. Therefore, the results of the water phantom with a maximum error of 4% can be used in practical applications instead of soft tissue. Moreover, the amount of differences obtained in each distance regarding using the soft tissue phantom could be corrected.

  14. 76 FR 68499 - Draft WaterSMART Cooperative Watershed Management Program Funding Opportunity Announcement

    Science.gov (United States)

    2011-11-04

    ... Office of the Secretary Draft WaterSMART Cooperative Watershed Management Program Funding Opportunity Announcement AGENCY: Office of the Assistant Secretary for Water and Science, Interior. ACTION: Notice of... Cooperative Watershed Management Program whose goals are to improve water quality and ecological...

  15. Human phantom

    CERN Multimedia

    CERN PhotoLab

    1973-01-01

    This human phantom has been received by CERN on loan from the State Committee of the USSR for the Utilization of Atomic Energy. It is used by the Health Physics Group to study personel radiation doses near the accelerators.

  16. Understanding local water conflict and cooperation: The case of Namwala District, Zambia

    Science.gov (United States)

    Funder, Mikkel; Mweemba, Carol; Nyambe, Imasiku; van Koppen, Barbara; Ravnborg, Helle Munk

    Understanding the nature of water conflict and cooperation is a crucial element in water governance within Integrated Water Resources Management (IWRM). Much of the recent attention to the issue has however focused on transboundary aspects, while we know rather less about the nature and dynamics of local water conflict and cooperation. Drawing on the work of the collaborative Competing for Water Research Programme, this article presents selected findings from a quantitative and qualitative mapping and exploration of water conflict and cooperation events in Namwala District of Zambia. It is found that local water competition situations often involve both conflictive and cooperative events in a dynamic succession of each other, but also that the majority of events are conflictive, and that they primarily take place between different types of water uses, and less frequently among the same types of uses. There is a distinct tendency for both conflictive and cooperative events to originate in the dry season, and many events are associated with water infrastructure development, particularly boreholes. The study found that most conflictive and cooperative events took place within individual communities, and only to a lesser extent between two or more communities or between districts. While third parties are involved in some events, these are primarily local village institutions such as Headmen. The article concludes by discussing the implications of these findings for local water governance, including the need to ensure that the very localized nature of such conflict and cooperation events is taken into consideration in the institutional development of IWRM.

  17. The U.S. Geological Survey Federal-State cooperative water- resources program; fiscal year 1987

    Science.gov (United States)

    Gilbert, B.K.; Mann, William B.

    1988-01-01

    The U.S. Geological Survey 's Federal-State Cooperative Water Resources Program (50-50 matching of funds) started in Kansas in 1895. During fiscal year (FY) 1987, hydrologic data collection, investigations, and research are being conducted in every state, Puerto Rico, and several territories in cooperation with 940 state, regional and local agencies. Federal funding of $55.3 million was matched by cooperating agencies; cooperators also provided $4.6 million unmatched, for a program total of about $115 million. The Cooperative Program accounted for almost 45% of the FY 1987 obligations of the Geological Survey 's Water Resources Division. The principal areas of emphasis during the year included groundwater contamination, stream quality, water supply and demand, and hydrologic hazards. Information is presented on program functions and priorities. Data collection activities are also described as is work related to water resources contamination. Several examples of current (1987) investigations are provided. (Author 's abstract)

  18. "Phantom ion effect" and the contact potential of the water-vapor interface.

    Science.gov (United States)

    Levin, Yan

    2008-09-28

    The contact (junction) potential between water-vapor and water-oil interfaces is studied theoretically. Unlike the previous studies, we show that ionic contribution to the contact potential vanishes when the concentration of aqueous electrolyte goes to zero. The incorrect prediction of a large ionic contribution to the junction potential in the infinite dilution limit, obtained in the earlier studies, is traced back to the inappropriate use of the grand-canonical ensemble for strongly inhomogeneous Coulomb systems. It is shown that for these systems, the thermodynamic limit is not reached even when the number of particles is astronomically large, on the order of 10(24). There is, therefore, no equivalence between statistical ensembles. For realistic, finite size systems, canonical calculation predicts a vanishing ionic contribution to the junction potentials of water-vapor and water-oil interfaces even for very concentrated electrolyte solutions.

  19. 77 FR 38339 - Dairyland Power Cooperative, La Crosse Boiling Water Reactor Exemption From Certain Security...

    Science.gov (United States)

    2012-06-27

    ... COMMISSION Dairyland Power Cooperative, La Crosse Boiling Water Reactor Exemption From Certain Security... Dairyland Power Cooperative (DPC). The LACBWR was a nuclear power plant of nominal 50 Mw electrical output... from the regulations in part 73 as it determines are authorized by law and will not endanger life...

  20. 77 FR 38338 - Dairyland Power Cooperative; La Crosse Boiling Water Reactor Exemption From Certain Security...

    Science.gov (United States)

    2012-06-27

    ... COMMISSION Dairyland Power Cooperative; La Crosse Boiling Water Reactor Exemption From Certain Security Requirements 1.0 Background The La Crosse Boiling Water Reactor (LACBWR) is owned and was operated by the..., which utilized a forced-circulation, direct-cycle boiling water reactor as its heat source. The plant is...

  1. Realizing Conflict, Negotiation, and Cooperation Concepts in the Context of International Water Courses

    Science.gov (United States)

    Dinar, Ariel; McKinney, Daene

    2010-01-01

    In this paper we offer a negotiation and cooperative game theory application to international water in the classroom. A simulation game was developed for the Aral Sea water dispute as part of a textbook prepared for teaching a diverse group of students a graduate-level International Water course. A condensed version of the Aral Sea Basin water…

  2. An algorithm for automated ROI definition in water or epoxy-filled NEMA NU-2 image quality phantoms.

    Science.gov (United States)

    Pierce Ii, Larry A; Byrd, Darrin W; Elston, Brian F; Karp, Joel S; Sunderland, John J; Kinahan, Paul E

    2016-01-08

    Drawing regions of interest (ROIs) in positron emission tomography/computed tomography (PET/CT) scans of the National Electrical Manufacturers Association (NEMA) NU-2 Image Quality (IQ) phantom is a time-consuming process that allows for interuser variability in the measurements. In order to reduce operator effort and allow batch processing of IQ phantom images, we propose a fast, robust, automated algorithm for performing IQ phantom sphere localization and analysis. The algorithm is easily altered to accommodate different configurations of the IQ phantom. The proposed algorithm uses information from both the PET and CT image volumes in order to overcome the challenges of detecting the smallest spheres in the PET volume. This algorithm has been released as an open-source plug-in to the Osirix medical image viewing software package. We test the algorithm under various noise conditions, positions within the scanner, air bubbles in the phantom spheres, and scanner misalignment conditions. The proposed algorithm shows run-times between 3 and 4 min and has proven to be robust under all tested conditions, with expected sphere localization deviations of less than 0.2 mm and variations of PET ROI mean and maximum values on the order of 0.5% and 2%, respectively, over multiple PET acquisitions. We conclude that the proposed algorithm is stable when challenged with a variety of physical and imaging anomalies, and that the algorithm can be a valuable tool for those who use the NEMA NU-2 IQ phantom for PET/CT scanner acceptance testing and QA/QC.

  3. Cooperativity in Surface Bonding and Hydrogen Bonding of Water and Hydroxyl at Metal Surfaces

    DEFF Research Database (Denmark)

    Schiros, T.; Ogasawara, H.; Naslund, L. A.;

    2010-01-01

    of the mixed phase at metal surfaces. The surface bonding can be considered to be similar to accepting a hydrogen bond, and we can thereby apply general cooperativity rules developed for hydrogen-bonded systems. This provides a simple understanding of why water molecules become more strongly bonded...... to the surface upon hydrogen bonding to OH and why the OH surface bonding is instead weakened through hydrogen bonding to water. We extend the application of this simple model to other observed cooperativity effects for pure water adsorption systems and H3O+ on metal surfaces.......We examine the balance of surface bonding and hydrogen bonding in the mixed OH + H2O overlayer on Pt(111), Cu(111), and Cu(110) via density functional theory calculations. We find that there is a cooperativity effect between surface bonding and hydrogen bonding that underlies the stability...

  4. 77 FR 23120 - Special Local Regulations; Lowcountry Splash Open Water Swim, Wando River and Cooper River, Mount...

    Science.gov (United States)

    2012-04-18

    ... Swim, Wando River and Cooper River, Mount Pleasant, SC AGENCY: Coast Guard, DHS. ACTION: Temporary... Wando River and Cooper River in Mount Pleasant, South Carolina during the Lowcountry Splash, a 2.4 mile... the Lowcountry Splash, a 2.4 mile open water swim in the Wando River and Cooper River along...

  5. U.S. Geological Survey federal-state cooperative water-resources program, fiscal year 1995

    Science.gov (United States)

    Lew, Melvin; Dodds, Betty

    1996-01-01

    The Federal-State Cooperative Program is a major U.S. Geological Survey (USGS) activity for the collection, analysis, and reporting of information on the quantity, quality, and use of the Nation's water resources. The fundamental characteristic of the program is that most of the work is undertaken by the USGS through joint-funding agreements, with State, regional, and local agencies providing at least one-half the funds. The main objectives of the program are (1) to collect, on a systematic basis, data needed for the continuing determi- nation and evaluation of the quantity, quality, and use of the Nation's water resources; and (2) to appraise the availability and the physical, chemical, and biological characteristics of surface and ground water through data analysis and interpretive water-resources investigations and research. During fiscal year (FY) 1995, Cooperative Program activities were underway in offices in every State, Puerto Rico, and several territories in concert with about 1,100 cooperating agencies. In FY 1995, Federal funding of $62.1 million as matched by cooperating agencies, which also provided more than $28.2 million unmatched for a total program of about $152 million. This amounted to nearly 38 percent of the total funds for the USGS's water-resources activities. This report presents examples of FY 1995 investigations, as well as information on hydrologic data collection and water-use activities.

  6. Reallocation of water in the state of New Mexico based on cooperative game theory

    Science.gov (United States)

    Rouhi Rad, M.

    2011-12-01

    Water allocation models often aim to maximize net benefits in the river basin based on the water rights, thus there is no motivation to use water efficiently by the users with lower marginal value for water. Water markets not only could help increase the net benefits over the basin but also will encourage the stakeholders to save the water and use it in transfer markets and increase their income. This issue can be viewed as a game in which stakeholders can play non-cooperatively and try to increase their own benefits using the amount of water assigned to them or they could cooperate and make coalitions in order to increase the total benefits in the coalition and the whole basin. The aim of this study is to reallocate the water based on cooperation among different stakeholders, namely agricultural, municipal and industrial and environmental, in the Upper Rio Grande river basin in the state of New Mexico in order to increase efficiency, sustainability and equity of water distribution in the basin using different game theory schemes such as Nucleolus and the Shapley Value.

  7. Financial tools to induce cooperation in power asymmetrical water systems

    Science.gov (United States)

    Denaro, Simona; Castelletti, Andrea; Giuliani, Matteo; Characklis, Gregory W.

    2017-04-01

    In multi-purpose water systems, power asymmetry is often responsible of inefficient and inequitable water allocations. Climate Change and anthropogenic pressure are expected to exacerbate such disparities at the expense of already disadvantaged groups. The intervention of a third party, charged with redefining water sharing policies to give greater consideration to equity and social justice, may be desirable. Nevertheless, to be accepted by private actors, this interposition should be coupled with some form of compensation. For a public agency, compensation measures may be burdensome, especially when the allowance is triggered by natural events whose timing and magnitude are subject to uncertainty. In this context, index based insurance contracts may represent a viable alternative option and reduce the cost of achieving socially desirable outcomes. In this study we explore soft measures to achieve global change mitigation by designing a hybrid coordination mechanism composed of i) a direct normative constraint and ii) an indirect financial compensatory tool. The performance of an index-based insurance (i.e. hedging) contract to be used as a compensation tool is evaluated relative to more traditional alternatives. First, the performance of the status quo system, or baseline (BL), is contrasted to an idealized scenario in which a central planner (CP) maximizes global efficiency. Then, the CP management is analyzed in order to identify an efficient water rights redistribution to be legally imposed on the advantaged stakeholders in the BL scenario. Finally, a hedging contract is designed to compensate those stakeholders more negatively affected by the legal constraint. The approach is demonstrated on a multi-purpose water system in Italy, where different decision makers individually manage the same resource. The system is characterized by a manifest power asymmetry: the upstream users, i.e., hydropower companies, are free to release their stored water in time

  8. SU-E-T-336: Dosimetric Properties of a New Solid Water High Equivalency Phantom for High-Energy Photon Beams

    Energy Technology Data Exchange (ETDEWEB)

    Araki, F; Ohno, T; Onitsuka, R [Kumamoto University, Kumamoto (Japan); Shimohigashi, Y [Kumamoto University Hospital, Kumamoto (Japan)

    2015-06-15

    Purpose: To investigate dosimetric properties in high-energy photon beams for a Solid Water High Equivalency (SWHE, SW557) phantom (Gammex) which was newly developed as water mimicking material. Methods: The mass density of SWHE and SWHE/water electron density ratio are 1.032 g/cm{sup 3} and 1.005 according to the manufacturer information, respectively. SWHE is more water equivalent material in physical characteristics and uniformity than conventional SW457. This study calculated the relative ionization ratio of water and SWHE as a function of depth from the cavity dose in PTW30013 and Exradin A19 Farmer-type ionization chambers using Monte Caro simulations. The simulation was performed with a 10 x 10 cm{sup 2} field at SAD of 100 cm for 4, 6, 10, 15, and 18 MV photons. The ionization ratio was also measured with the PTW30013 chamber for 6 and 15 MV photons. In addition, the overall perturbation factor of both chambers was calculated for both phantoms. Results: The relative ionization ratio curves for water and SWHE was in good agreement for all photon energies. The ionization ratio of water/SWHE for both chambers was 0.999–1.002, 0.999–1.002, 1.001–1.004, 1.004–1.007, and 1.006–1.010 at depths of over the buildup region for 4, 6, 10, 15, and 18 MV photons, respectively. The ionization ratio of water/SWHE increased up to 1% with increasing the photon energy. The measured ionization ratio of water/SWHE for 6 and 15 MV photons agreed well with calculated values. The overall perturbation factor for both chambers was 0.983–0.988 and 0.978–0.983 for water and SWHE, respectively, in a range from 4 MV to 18 MV. Conclusion: The depth scaling factor of water/SWHE was equal to unity for all photon energies. The ionization ratio of water/SWHE at a reference depth was equal to unity for 4 and 6 MV and larger up to 0.7% than unity for 18 MV.

  9. Analysis of dosimetry of a Gamma Knife Perfexion using polystyrene and solid water phantoms for small volume ionization chambers; Analise da dosimetria de um Gamma Knife Perfexion utilizando phantoms de poliestireno e de agua solida para camaras de ionizacao de volume pequeno

    Energy Technology Data Exchange (ETDEWEB)

    Costa, N.A.; Potiens, M.P.A., E-mail: nathaliaac@ymail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Saraiva, C.W.C. [Hospital do Coracao (HCor), Sao Paulo, SP (Brazil); Benmakhlouf, H. [Stockholm University, Karolinska Hospital (Sweden)

    2016-07-01

    The Gamma Knife Perfexion (GKP) is a radiosurgery equipment that has been developed by Elekta. Its dose-rate calibration is performed using phantoms developed by Elekta and a small volume ionization chamber. The purpose of this study was to evaluate the collected charge values obtained in its dosimetry using two different phantoms, polystyrene and solid water and the ion chambers PTW Semiflex, volume 0,125 cm{sup 3}, model 31010 and PTW Pinpoint, volume 0,016 cm{sup 3}, model 31016. (author)

  10. Phantom limb pain

    Science.gov (United States)

    Amputation - phantom limb ... Bang MS, Jung SH. Phantom limb pain. In: Frontera, WR, Silver JK, Rizzo TD, eds. Essentials of Physical Medicine and Rehabilitation . 3rd ed. Philadelphia, PA: Elsevier ...

  11. Cooperative drought adaptation: Integrating infrastructure development, conservation, and water transfers into adaptive policy pathways

    Science.gov (United States)

    Zeff, Harrison B.; Herman, Jonathan D.; Reed, Patrick M.; Characklis, Gregory W.

    2016-09-01

    A considerable fraction of urban water supply capacity serves primarily as a hedge against drought. Water utilities can reduce their dependence on firm capacity and forestall the development of new supplies using short-term drought management actions, such as conservation and transfers. Nevertheless, new supplies will often be needed, especially as demands rise due to population growth and economic development. Planning decisions regarding when and how to integrate new supply projects are fundamentally shaped by the way in which short-term adaptive drought management strategies are employed. To date, the challenges posed by long-term infrastructure sequencing and adaptive short-term drought management are treated independently, neglecting important feedbacks between planning and management actions. This work contributes a risk-based framework that uses continuously updating risk-of-failure (ROF) triggers to capture the feedbacks between short-term drought management actions (e.g., conservation and water transfers) and the selection and sequencing of a set of regional supply infrastructure options over the long term. Probabilistic regional water supply pathways are discovered for four water utilities in the "Research Triangle" region of North Carolina. Furthermore, this study distinguishes the status-quo planning path of independent action (encompassing utility-specific conservation and new supply infrastructure only) from two cooperative formulations: "weak" cooperation, which combines utility-specific conservation and infrastructure development with regional transfers, and "strong" cooperation, which also includes jointly developed regional infrastructure to support transfers. Results suggest that strong cooperation aids utilities in meeting their individual objectives at substantially lower costs and with less overall development. These benefits demonstrate how an adaptive, rule-based decision framework can coordinate integrated solutions that would not be

  12. Water-Energy Nexus in Shared River Basins: How Hydropower Shapes Cooperation and Coordination

    Directory of Open Access Journals (Sweden)

    Kouangpalath Phimthong

    2015-01-01

    Full Text Available The construction of hydropower plants on transboundary rivers is seldom done with equal benefits to all riparians, and therefore presents coordination and cooperation challenges. Without a supra-national authority in charge of transboundary river basins, coordination between sectors (water, energy and environment and cooperation between countries largely depends on willingness of the individual nation states and the power relations between these countries. This paper discusses how the interests and relative power positions of actors in transboundary water management shape the outcomes, and what roles are played by River Basin Organisations and foreign investors (especially in hydropower development. These issues are illustrated with examples from the Mekong river in Southeast Asia (Laos, Thailand, Cambodia and Vietnam, the Euphrates-Tigris (Turkey, Syria, Iraq, Iran and Kuwait and the Çoruh in Turkey and Georgia.

  13. Development cooperation in water and sanitation: is it based on the human rights framework?

    Science.gov (United States)

    Brown, Colin; Heller, Léo

    2017-07-01

    The water and sanitation sector is verifiably receiving increased attention and funding through international development cooperation. Not least because of the way that it affects incentives and institutions in partner countries, development cooperation can have either positive or negative effects on human rights though. The consolidated frameworks for the human rights to water and sanitation is becoming linked to the international community's coordinated development efforts, as evidenced notably in the 2030 Agenda for Sustainable Development. However, a review of major funders' official policies for development cooperation in the sector suggests that many only partially endorse the frameworks for the human rights to water and sanitation. An observation of development cooperation flows to the sector allows the hypothesis to be advanced that worldwide inequalities in access to these services may be reduced through a full and clear application of the human rights framework in development cooperation activities. The article presents findings of this research and explores key stakes for development cooperation in the water and sanitation sector that are relevant for their ability to either negatively or positively contribute to the realization of human rights. Resumen El sector de agua y saneamiento ha recibido creciente atención y financiación a través de la cooperación internacional para el desarrollo. La cooperación para el desarrollo puede tener efectos tanto positivos cuanto negativos sobre los derechos humanos. El hito que consolida los derechos humanos al agua y al saneamiento están articulados a esfuerzos de cooperación para el desarrollo promovidos por la comunidad internacional, como se evidencia en la Agenda 2030 para el Desarrollo Sostenible. Sin embargo, una revisión de las políticas oficiales de los principales financiadores del sector sugiere que muchos de ellos aprueban solo parcialmente los hitos de los derechos humanos al agua y el

  14. Managing phantom pain.

    Science.gov (United States)

    Manchikanti, Laxmaiah; Singh, Vijay

    2004-07-01

    Since the first medical description of post-amputation phenomena reported by Ambrose Paré, persistent phantom pain syndromes have been well recognized. However, they continue to be difficult to manage. The three most commonly utilized terms include phantom sensation, phantom pain, and stump pain. Phantom limb sensation is an almost universal occurrence at some time during the first month following surgery. However, most phantom sensations generally resolve after two to three years without treatment, except in the cases where phantom pain develops. The incidence of phantom limb pain has been reported to vary from 0% to 88%. The incidence of phantom limb pain increases with more proximal amputations. Even though phantom pain may diminish with time and eventually fade away, it has been shown that even two years after amputation, the incidence is almost the same as at onset. Consequently, almost 60% of patients continue to have phantom limb pain after one year. In addition, phantom limb pain may also be associated with multiple pain problems in other areas of the body. The third symptom, stump pain, is located in the stump itself. The etiology and pathophysiological mechanisms of phantom pain are not clearly defined. However, both peripheral and central neural mechanisms have been described, along with superimposed psychological mechanisms. Literature describing the management of phantom limb pain or stump pain is in its infancy. While numerous treatments have been described, there is little clinical evidence supporting drug therapy, psychological therapy, interventional techniques or surgery. This review will describe epidemiology, etiology and pathophysiological mechanisms, risk factors, and treatment modalities. The review also examines the effectiveness of various described modalities for prevention, as well as management of established phantom pain syndromes.

  15. Pediatric brain tumor consortium multisite assessment of apparent diffusion coefficient z-axis variation assessed with an ice-water phantom.

    Science.gov (United States)

    Mulkern, Robert V; Ricci, Kelsey I; Vajapeyam, Sridhar; Chenevert, Thomas L; Malyarenko, Dariya I; Kocak, Mehmet; Poussaint, Tina Young

    2015-03-01

    Magnetic resonance diffusion imaging can characterize physiologic characteristics of pediatric brain tumors used to assess therapy response. The purpose of this study was to assess the variability of the apparent diffusion coefficient (ADC) along z-axis of scanners in the multicenter Pediatric Brain Tumor Consortium (PBTC). Ice-water diffusion phantoms for each PBTC site were distributed with a specific diffusion imaging protocol. The phantom was scanned four successive times to 1) confirm water in the tube reached thermal equilibrium and 2) allow for assessment of intra-examination ADC repeatability. ADC profiles across slice positions for each vendor and institution combination were characterized using linear regression modeling with a quadratic fit. Eleven sites collected data with a high degree of compliance to the diffusion protocol for each scanner. The mean ADC value at slice position zero for vendor A was 1.123 × 10(-3) mm(2)/s, vendor B was 1.0964 × 10(-3) mm(2)/s, and vendor C was 1.110 × 10(-3) mm(2)/s. The percentage coefficient of variation across all sites was 0.309% (standard deviation = 0.322). The ADC values conformed well to a second-order polynomial along the z-axis, (ie, following a linear model pattern with quadratic fit) for vendor-institution combinations and across vendor-institution combinations as shown in the longitudinal model. Assessment of the variability of diffusion metrics is essential for establishing the validity of using these quantitative metrics in multicenter trials. The low variability in ADC values across vendors and institutions and validates the use of ADC as a quantitative tumor marker in pediatric multicenter trials. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  16. Managing the drinking water catchment areas: the French agricultural cooperatives feed back.

    Science.gov (United States)

    Charrière, Séverine; Aumond, Claire

    2016-06-01

    The quality of raw water is problematic in France, largely polluted by nitrates and pesticides (Mueller and Helsel, Nutrients in the nation's waters-too much of a good thing? Geological Survey (U.S.), 1996; European Environment Agency, European waters-assessment of status and pressures, 2012).This type of pollution, even though not always due to agriculture (example of the catchment of Ambleville, county 95, France where the nitrate pollution is mainly due to sewers (2012)), has been largely related to the agricultural practices (Sci Total Environ 407:6034-6043, 2009).Taking note of this observation, and instead of letting it paralyze their actions, the agricultural cooperatives decided with Agrosolutions to act directly on the field with their subscribers to change the agricultural practices impacting the water and the environment.This article shows how the French agricultural cooperatives transformed the awareness of the raw water quality problem into an opportunity for the development and implementation of more precise and responsible practices, to protect their environment. They measure in order to pilot, co-construct and build the best action plans possible according to the three pillars of environment, economy and agronomy.

  17. Energy efficient cooperation in underlay RFID cognitive networks for a water smart home.

    Science.gov (United States)

    Nasir, Adnan; Hussain, Syed Imtiaz; Soong, Boon-Hee; Qaraqe, Khalid

    2014-09-30

    Shrinking water resources all over the world and increasing costs of water consumption have prompted water users and distribution companies to come up with water conserving strategies. We have proposed an energy-efficient smart water monitoring application in [1], using low power RFIDs. In the home environment, there exist many primary interferences within a room, such as cell-phones, Bluetooth devices, TV signals, cordless phones and WiFi devices. In order to reduce the interference from our proposed RFID network for these primary devices, we have proposed a cooperating underlay RFID cognitive network for our smart application on water. These underlay RFIDs should strictly adhere to the interference thresholds to work in parallel with the primary wireless devices [2]. This work is an extension of our previous ventures proposed in [2,3], and we enhanced the previous efforts by introducing a new system model and RFIDs. Our proposed scheme is mutually energy efficient and maximizes the signal-to-noise ratio (SNR) for the RFID link, while keeping the interference levels for the primary network below a certain threshold. A closed form expression for the probability density function (pdf) of the SNR at the destination reader/writer and outage probability are derived. Analytical results are verified through simulations. It is also shown that in comparison to non-cognitive selective cooperation, this scheme performs better in the low SNR region for cognitive networks. Moreover, the hidden Markov model's (HMM) multi-level variant hierarchical hidden Markov model (HHMM) approach is used for pattern recognition and event detection for the data received for this system [4]. Using this model, a feedback and decision algorithm is also developed. This approach has been applied to simulated water pressure data from RFID motes, which were embedded in metallic water pipes.

  18. Sharing Water on the Iberian Peninsula: A Europeanisation Approach to Explaining Transboundary Cooperation

    Directory of Open Access Journals (Sweden)

    Jeanie J. Bukowski

    2011-06-01

    Full Text Available This paper applies the Europeanisation perspective to the policy change evident in the 1998 Convention on Cooperation for the Protection and Sustainable Use of the Waters of the Spanish-Portuguese Basins (Albufeira convention. The 'top-down' Europeanisation framework is applied here to a case involving simultaneous, joint adaptation to European Union (EU policy in terms of two states negotiating a transborder agreement that encompasses institutional changes required by that policy. This study provides an analysis of transnational policy change in an area of vital importance in international relations, namely, shared freshwater resources. It finds that while the Europeanisation framework may be applied effectively to transboundary adaptation (not just cross-country comparison and goes a long way in explaining cooperation on the Iberian Peninsula, it is incomplete in its consideration of other influences within and beyond 'Europe', from the global to the local levels.

  19. "Phantom" carpal tunnel syndrome.

    Science.gov (United States)

    Braverman, D L; Root, B C

    1997-10-01

    Phantom sensation is ubiquitous among persons who have had amputation; however, if it develops into phantom pain, a thorough clinical investigation must ensue. We illustrate this with the case of a 49-year-old woman, 14 years after traumatic amputation of her left 2nd through 5th fingers, and 10 years after traumatic left transfemoral amputation. She had had phantom sensation in her absent fingers for years and developed progressive pain in her phantom fingers 3 months before presentation. Nerve conduction study revealed a high-normal distal motor latency of the left median nerve and a positive Bactrian test (sensitivity 87%). She was diagnosed with "phantom" carpal tunnel syndrome and treated with a resting wrist splint, decreased weight bearing on the left upper limb, and two corticosteroid carpal tunnel injections with marked improvement. Clinicians should recognize that phantom pain may be referred from a more proximal region and may be amenable to conservative management.

  20. [Phantom limb pain].

    Science.gov (United States)

    Steffen, Peter

    2006-06-01

    Almost everyone who has amputated a limb will experience a phantom limb. They have the vivid impression, that the limb is still present. 60 to 70% of these amputees will suffer from phantom limb pain. The present paper gives an overview of the incidence and the characteristics of the so called "post amputation syndrome". Possible mechanism of this phenomena are presented, including peripheral, spinal, and central theories. Treatment of phantom limb pain is sometimes very difficult. It includes drug therapy, psychological therapy, physiotherapy as well as the prevention of phantom limb pain with regional analgesia techniques.

  1. Recipes to make organic phantoms for diffusive optical spectroscopy.

    Science.gov (United States)

    Quarto, Giovanna; Pifferi, Antonio; Bargigia, Ilaria; Farina, Andrea; Cubeddu, Rinaldo; Taroni, Paola

    2013-04-10

    Three recipes are presented to make tissue constituent-equivalent phantoms of water and lipids. Different approaches to prepare the emulsion are proposed. Nature phantoms are made using no emulsifying agent, but just a professional disperser; instead Agar and Triton phantoms are made using agar or Triton X-100, respectively, as agents to emulsify water and lipids. Different water-to-lipid ratios ranging from 30% to 70% by mass were tested. A broadband time-resolved diffuse optical spectroscopy system was used to characterize the phantoms in terms of optical properties and composition. For some water/lipid ratios the emulsion fails or the phantom has limited lifetime, but in most cases the recipes provide phantoms with a high degree of homogeneity [coefficient of variation (CV) of 4.6% and 1.5% for the absorption and reduced scattering coefficient, respectively] and good reproducibility (CV of 8.3% and 12.4% for absorption and reduced scattering coefficient, respectively).

  2. Monte Carlo Evaluation of Gamma Knife Dose Profile in Real Brain Phantom

    Directory of Open Access Journals (Sweden)

    Ali Aghaebrahimian

    2016-03-01

    The calculation of the real phantom showed that water and polystyrene could function similarly, while evaluating dosimetry parameters in the Gamma Knife system; thus, water and polystyrene are not appropriate phantom matters for this purpose.

  3. Phantom cosmologies and fermions

    CERN Document Server

    Chimento, Luis P; Forte, Monica; Kremer, Gilberto M

    2007-01-01

    Form invariance transformations can be used for constructing phantom cosmologies starting with conventional cosmological models. In this work we reconsider the scalar field case and extend the discussion to fermionic fields, where the "phantomization" process exhibits a new class of possible accelerated regimes.

  4. 21. Phantom pain.

    NARCIS (Netherlands)

    Wolff, A.P.; Vanduynhoven, E.; Kleef, M. van; Huygen, F.; Pope, J.E.; Mekhail, N.

    2011-01-01

    Phantom pain is pain caused by elimination or interruption of sensory nerve impulses by destroying or injuring the sensory nerve fibers after amputation or deafferentation. The reported incidence of phantom limb pain after trauma, injury or peripheral vascular diseases is 60% to 80%. Over half the p

  5. Conflict, Cooperation, and Viability: Interstate Water Resources and Domestic Water Use in the Middle East

    Science.gov (United States)

    2011-03-01

    relations between states that share major waterways in the Middle East. This thesis also examines current water management strategies and their potential...may be a secondary cause or just the excuse needed to act on existing tensions. Additionally, this thesis reveals that current water management strategies in...happened, despite the intense friction between Turkey, Syria, and Iraq. Chapter V also is a case study, covering the internal water management strategies specific

  6. Quantifying cooperativity in water clusters: an attempt towards obtaining a generalised equation

    Science.gov (United States)

    Saha, Soumen; Narahari Sastry, G.

    2015-10-01

    The current study describes the development of a general equation of cooperativity energy (CE) for an n-mer system based on the difference between interaction energy of the system and the sum of interaction energy of its dimeric subunits. The counterpoise corrected generalised CE equation of n-mer system has also been developed. In order to validate these two generalised equations, we have considered four different kinds of water clusters, viz. W1D, W2D, W2D-H and W3D, ((H2O)n: n = 3-10), with the increasing cluster size as well as changing arrangements. The CE obtained from the two generalised equations follow the trend W3D > W2D-H > W2D > W1D. The deviation at n = 6 for W3D clusters in the plot of CE with cluster size has also been observed for O-H stretching frequencies, electron density and the Laplacian of the electron density plots. The contrastingly higher CE for cyclic pentamer compared to hexamer is in accordance with earlier observations as well as computed average hydrogen bond lengths. We have observed that the average charge value is more on oxygen atoms of pentamer than hexamer resulting in the shortening of hydrogen bond in pentamer and hence the CE values are more for pentamer than hexamer. We have shown that CE has the capability to quantify the cooperativity effect in water clusters.

  7. Highlights of the 1983 Federal-state cooperative water resources program

    Science.gov (United States)

    Gilbert, B.K.; Buchanan, T.J.

    1983-01-01

    The U.S. Geological Survey Federal-State Cooperative Water Resources Program in fiscal year 1983 continued to concentrate on investigations of highest priority to the Nation. Hydrologic data collection and interpretive studies were underway in every State, Puerto Rico, and several U.S. territories with focus on such current concerns as ground-water contamination, floods, impacts of toxic wastes, acid precipitation, and stream quality. During the year, this 50-50 matching program was carried out in working partnership with more than 800 State, regional, and local agencies. Joint funding from all sources totaled approximately $92 million. Details of the program are mutually negotiated at the working level by representatives of the Survey and representatives of the cooperating agencies. The pooling of interests results in a balanced effort that directs combined resources to hydrologic investigations having the most significance to both parties. A few of the highlights for FY 1983, and how the program is developed with other agencies are described. (USGS)

  8. Energy Efficient Cooperation in Underlay RFID Cognitive Networks for a Water Smart Home

    Directory of Open Access Journals (Sweden)

    Adnan Nasir

    2014-09-01

    Full Text Available Shrinking water  resources all over the world and increasing  costs of water consumption  have prompted  water users  and distribution companies  to come up with water conserving strategies. We have proposed an energy-efficient  smart water monitoring application in [1], using low power RFIDs. In the home environment,  there exist many primary interferences within a room, such as cell-phones,  Bluetooth  devices, TV signals, cordless phones and WiFi devices.  In order to reduce the interference  from our proposed RFID network for these primary  devices, we have proposed a cooperating  underlay  RFID cognitive network for our smart application on water.  These underlay  RFIDs should strictly adhere to the interference thresholds to work in parallel with the primary wireless devices [2].  This work is an extension of our previous  ventures proposed in [2,3], and we enhanced the previous efforts by introducing  a new system model and RFIDs.  Our proposed scheme is mutually energy efficient and maximizes the signal-to-noise ratio (SNR for the RFID link, while keeping the interference levels for the primary  network below a certain threshold. A closed form expression for the probability density function (pdf of the SNR at the destination reader/writer and outage probability are derived. Analytical results are verified through simulations. It is also shown that in comparison to non-cognitive selective cooperation,  this scheme performs  better in the low SNR region for cognitive networks. Moreover, the hidden Markov model’s (HMM multi-level variant hierarchical hidden Markov model (HHMM approach is used for pattern recognition and event detection for the data received for this system [4]. Using this model, a feedback and decision algorithm is also developed.  This approach has been applied  to simulated water pressure data from RFID motes, which were embedded in metallic water pipes.

  9. International Cooperation for the Training of Water Managers from Developing Countries

    Science.gov (United States)

    Aswathanarayana, U.

    2007-12-01

    Water is the key to the well being of a community. On one hand, water security is linked to food security, as food cannot be grown without water. On the other hand, water security is linked to environmental security, as water is needed to maintain the health of a community. International cooperation is proposed for the training in Hyderabad, India, with international faculty, of ~ 300 water managers from the developing countries at an estimated cost of ~USD 3300/- per candidate (including ~ USD 1800/- for international travel), through ten interactive and customized training programmes during the period of five years, to enable them to address two crucial issues affecting the poor in the developing countries, namely, access to affordable water and coping with water scarcity. Ways of Good governance and geographical targeting of poverty alleviation programmes are built into each training programme. Each training programme will be for about three weeks (inclusive of field work). Each course will have a component common to all, plus a component customized to the biophysical and socioeconomic situation in a candidate's country. Ten course manuals will be produced. which can later be published commercially as low-cost volumes, for the benefit of the readership in the Developing countries . Each candidate will be provided his own computer, and software, and individual faculty adviser. On the basis of the training received, a candidate should be able to carry with him at the end of the course a draft outline of techno-socio-economic action plan for his country/area in respect of the theme of the course, prepared by himself/herself. A copy of this outline would be provided to the World Bank, and relevant organizations for follow- up activity

  10. Water equivalence study of some phantoms based on effective photon energy, effective atomic numbers and electron densities for clinical MV X-ray and Co-60 γ-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Kurudirek, Murat, E-mail: mkurudirek@gmail.com [Faculty of Science, Department of Physics, Ataturk University, 25240 Erzurum (Turkey)

    2013-02-11

    A previously proposed procedure has been applied to some water equivalent phantoms namely PMMA, Polystyrene, Solid Water (WT1), RW3 and ABS for the first time to compute effective photon energy (E{sub eff}), effective atomic numbers (Z{sub eff}) and electron densities (ne{sub eff}) for different MV X-ray beams and Co-60 gamma beam which are heterogeneous in energy. For the purpose of the present investigation, effective atomic cross-sections of the given materials have been determined first to obtain effective photon energies which were further used for calculation of Z{sub eff} and ne{sub eff}. Similar procedure was adopted for Co-60 γ-rays to check the validity of the present method. Results were found to be quite satisfactory. When it comes to the water equivalence, the E{sub eff} results showed that the RW3 and ABS phantoms are more effective for 6 MV beam whereas RW3 and Polystyrene are more effective for 15 MV and Co-60 beams, respectively. The ABS and WT1 phantoms have better water equivalences than the others according to the Z{sub eff} and ne{sub eff} results, respectively.

  11. Thermal-Hydraulic Research Review and Cooperation Outcome for Light Water Reactor Fuel

    Energy Technology Data Exchange (ETDEWEB)

    In, Wang Kee; Shin, Chang Hwan; Lee, Chan; Chun, Tae Hyun; Oh, Dong Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Chi Young [Pukyong Nat’l Univ., Busan (Korea, Republic of)

    2016-12-15

    The fuel assembly for pressurized water reactor (PWR) consists of fuel rod bundle, spacer grid and bottom/top end fittings. The cooling water in high pressure and temperature is introduced in lower plenum of reactor core and directed to upper plenum through the subchannel which is formed between the fuel rods. The main thermalhydraulic performance parameters for the PWR fuel are pressure drop and critical heat flux in normal operating condition, and quenching time in accident condition. The Korea Atomic Energy Research Institute (KAERI) has been developing an advanced PWR fuel, dual-cooled annular fuel and accident tolerant fuel for the enhancement of fuel performance and the localization. For the key thermal-hydraulic technology development of PWR fuel, the KAERI LWR fuel team has conducted the experiments for pressure drop, turbulent flow mixing and heat transfer, critical heat flux(CHF) and quenching. The computational fluid dynamics (CFD) analysis was also performed to predict flow and heat transfer in fuel assembly including the spent fuel assembly in dry cask for interim repository. In addition, the research cooperation with university and nuclear fuel company was also carried out to develop a basic thermalhydraulic technology and the commercialization.

  12. An MRI phantom using carrageenan gel

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Hirokazu; Kuroda, Masahiro; Yoshimura, Koichi; Kawasaki, Shoji; Yamamoto, Naotake; Tanaka, Akio; Hiraki, Yoshio [Okayama Univ. (Japan). School of Medicine; Uchida, Nobue; Sugimura, Kazuro

    2000-12-01

    We have developed a new solid type carrageenan gel phantom. The ingredients of the new gel are carrageenan, manganese chloride, sodium chloride, sodium azide, and water. The gel phantom has sufficient strength to form a torso without the use of a reinforcing agent. A phantom of a desired shape can be created by pouring a hot solution of carrageenan into a mold. The phantom can then be cut easily with a knife and trimmed into the desired shape. The recommended concentrations of the ingredients are; 5 wt% carrageenan, 0.2 mM MnCl{sub 2}, 0.19 wt% NaCl, 0.1 wt% NaN{sub 3}, with the remainder being water. T{sub 2} and T{sub 1} of this phantom at 1.5 T are 84.9 ms and 429 ms respectively. The conductivity and relative dielectric constant at 63.8 MHz are 0.769 S/m and 81.4 respectively. (author)

  13. Power-Sharing in the English Lowlands? The Political Economy of Farmer Participation and Cooperation in Water Governance

    Directory of Open Access Journals (Sweden)

    Luke Whaley

    2015-02-01

    Full Text Available Participatory and cooperative forms of water governance have become regular features of government discourse and stated policy objectives in England. We consider this aspiration from the perspective of farmers in the English lowlands, by analysing the current power dynamic that exists among these farmers, and between them and the key stakeholders involved in water management. To do this we undertake a political economy analysis that places lowland farming and water governance within the evolution of historical processes that, over time, have influenced the ability of farmers to participate in the governance of their water environment. These historical developments are interpreted through the lens of the Power Cube, an analytical tool for thinking about the interplay between different forms of power operating in different types of spaces and at different levels of governance. Our findings reveal that, despite there being a number of structural changes that provide lowland farmers with the opportunity to participate and cooperate in water governance, three distinct barriers stand in the way. These relate to the power 'within' these farmers, which continues to align with a productivist ideology founded on individualism and competition, often at the expense of the environment; the power that government water managers still exercise 'over' farmers instead of 'with' them; and the relationship between lowland farming and environmental interests, where historically the two sides’ power 'to' act has been diametrically opposed. The findings point to the importance of developing suitable programmes designed to support and incentivize farmer participation and cooperation.

  14. Cooperative and adaptive transboundary water governance in Canada's Mackenzie River Basin: status and prospects

    Directory of Open Access Journals (Sweden)

    Michelle Morris

    2016-03-01

    Full Text Available Canada's Mackenzie River Basin (MRB is one of the largest relatively pristine ecosystems in North America. Home to indigenous peoples for millennia, the basin is also the site of increasing resource development, notably fossil fuels, hydroelectric power resources, minerals, and forests. Three provinces, three territories, the Canadian federal government, and Aboriginal governments (under Canada's constitution, indigenous peoples are referred to as "Aboriginal" have responsibilities for water in the basin, making the MRB a significant setting for cooperative, transboundary water governance. A framework agreement that provides broad principles and establishes a river basin organization, the MRB Board, has been in place since 1997. However, significant progress on completing bilateral agreements under the 1997 Mackenzie River Basin Transboundary Waters Master Agreement has only occurred since 2010. We considered the performance of the MRB Board relative to its coordination function, accountability, legitimacy, and overall environmental effectiveness. This allowed us to address the extent to which governance based on river basin boundaries, a bioregional approach, could contribute to adaptive governance in the MRB. Insights were based on analysis of key documents and published studies, 19 key informant interviews, and additional interactions with parties involved in basin governance. We found that the MRB Board's composition, its lack of funding and staffing, and the unwillingness of the governments to empower it to play the role envisioned in the Master Agreement mean that as constituted, the board faces challenges in implementing a basin-wide vision. This appears to be by design. The MRB governments have instead used the bilateral agreements under the Master Agreement as the primary mechanism through which transboundary governance will occur. A commitment to coordinating across the bilateral agreements is needed to enhance the prospects for

  15. Cooperation on Water management issues, Argentina : Project in the framework of Bilateral Cooperation between Argentina and the Netherlands : Case studies on water management issues in Argentina

    NARCIS (Netherlands)

    Querner, E.P.; Morabito, J.A.; Rebori, G.

    2007-01-01

    In Argentina parts of the country have problems encountered from too much water or suffer serious water shortages. The Humid Pampas encounter an increased rainfall since the 1970’s. In Mendoza Province water resources are limited and all the water from the rivers is used for agriculture, drinking

  16. Jamitons: Phantom Traffic Jams

    Science.gov (United States)

    Kowszun, Jorj

    2013-01-01

    Traffic on motorways can slow down for no apparent reason. Sudden changes in speed by one or two drivers can create a chain reaction that causes a traffic jam for the vehicles that are following. This kind of phantom traffic jam is called a "jamiton" and the article discusses some of the ways in which traffic engineers produce…

  17. Jamitons: Phantom Traffic Jams

    Science.gov (United States)

    Kowszun, Jorj

    2013-01-01

    Traffic on motorways can slow down for no apparent reason. Sudden changes in speed by one or two drivers can create a chain reaction that causes a traffic jam for the vehicles that are following. This kind of phantom traffic jam is called a "jamiton" and the article discusses some of the ways in which traffic engineers produce…

  18. The Phantom brane revisited

    Science.gov (United States)

    Sahni, Varun

    2016-07-01

    The Phantom brane is based on the normal branch of the DGP braneworld. It possesses a phantom-like equation of state at late times, but no big-rip future singularity. In this braneworld, the cosmological constant is dynamically screened at late times. Consequently it provides a good fit to SDSS DR11 measurements of H(z) at high redshifts. We obtain a closed system of equations for scalar perturbations on the brane. Perturbations of radiation, matter and the Weyl fluid are self-consistently evolved until the present epoch. We find that the late time growth of density perturbations on the brane proceeds at a faster rate than in ΛCDM. Additionally, the gravitational potentials φ, Ψ evolve differently on the brane than in ΛCDM, for which φ = Ψ. On the Brane, by contrast, the ratio φ/Ψ exceeds unity during the late matter dominated epoch (z ≤ 50). These features emerge as smoking gun tests of phantom brane cosmology and allow predictions of this scenario to be tested against observations of galaxy clustering and large scale structure. The phantom brane also displays a pole in its equation of state, which provides a key test of this dark energy model.

  19. Phantom pain after eye amputation

    DEFF Research Database (Denmark)

    Rasmussen, Marie L R; Prause, Jan U; Toft, Peter B

    2011-01-01

    Purpose: To characterize the quality of phantom pain, its intensity and frequency following eye amputation. Possible triggers and relievers of phantom pain are investigated. Methods: The hospital database was searched using surgery codes for patients who received ocular evisceration, enucleation,...... appears to be similar to the phantom pain suffered by limb amputees. Patients should be informed about this potential complication before surgery.......Purpose: To characterize the quality of phantom pain, its intensity and frequency following eye amputation. Possible triggers and relievers of phantom pain are investigated. Methods: The hospital database was searched using surgery codes for patients who received ocular evisceration, enucleation...... was conducted by a trained interviewer. Results: Of the 173 patients in the study, 39 experienced phantom pain. The median age of patients who had experienced phantom pain was 45 years (range: 19–88). Follow-up time from eye amputation to participation in the investigation was 4 years (range: 2–46). Phantom...

  20. Assessing the value of cooperation and information exchange in large water resources systems by agent-based optimization

    Science.gov (United States)

    Giuliani, M.; Castelletti, A.

    2013-07-01

    Many large-scale water resources systems, especially in transboundary contexts, are characterized by the presence of several and conflicting interests and managed by multiple, institutionally independent decision makers. These systems are often studied adopting a centralized approach based on the assumption of full cooperation and information exchange among the involved parties. Such a perspective is conceptually interesting to quantify the best achievable performance but might have little practical impact given the real political and institutional setting. In this work, we propose a novel decision-analytic framework based on multiagent systems to model and analyze different levels of cooperation and information exchange among multiple decision makers. The Zambezi River basin is used as a case study. According to the proposed agent-based optimization approach, each agent represents a decision maker, whose decisions are defined by an explicit optimization problem considering only the agent's local interests. The economic value of information exchange is estimated comparing a noncooperative setting, where agents act independently, with the first basic level of cooperation, i.e., coordination, characterized by full information exchange. The economic value of cooperation is also estimated by comparison with the ideal, fully cooperative management of the system. Results show that coordination, obtained with complete information exchange, allows the downstream agents to better adapt to the upstream behaviors. The impact of information exchange depends on the objective considered, and we show coordination to be particularly beneficial to environmental interests.

  1. Study of Mechanisms for Development and Strengthening of Water User Cooperatives (Case Study of Aras River Basin: Application of AHP Method

    Directory of Open Access Journals (Sweden)

    Rohallah maghabl

    2014-06-01

    Full Text Available Water user cooperatives were formed due to consideration to people's empowerment and participation in water investment and management. The purpose of this study was to investigate the mechanisms of development and strengthening of water user cooperatives in the Aras River Basin. The study population consisted of the management board members of the water user cooperatives in the Aras Basin in the year 2012. Respondents were selected by purposeful stratified sampling method. Having the data collected by interviews and questionnaires, the Analytic Hierarchy Process (through the software Expert Choice 11 was used to prioritize mechanisms for the development and strengthening of water user cooperatives. Based on the final weights, criterias including supportive strategies, education - extension, policy, communications and legal mechanisms, were prioritized, respectively. The results of the sensitivity analysis showed that sub-criterias including reallocation of credit to change the traditional irrigation to drip and sprinkler irrigation, holding extension and educational courses purposed at promoting farmers’knowledge about their responsibilities for the formation and management of water user cooperatives collaborated with the department of Jihad Agricultural Organization (JKO, the department of Cooperatives and Regional Water Organization; credit and investment provision to improve the processing and package industries, modeling appropriate cropping systems based on the area capacity were the most influential sub-criterias in developing and strengthening water user cooperatives.

  2. Dosimetry with phantom for total body irradiation (TBI)

    Energy Technology Data Exchange (ETDEWEB)

    Tezuka, Takako; Sakakura, Noriyuki; Obata, Yasunori; Tabushi, Katuyoshi; Kondou, Satoru [Nagoya Univ. (Japan). School of Health Sciences; Koyama, Syuuji; Aoyama, Yuuichi; Shimohira, Akiyo [Nagoya Univ. (Japan). Hospital

    2002-04-01

    Total body irradiation (TBI) is being used as a method of preparation for bone marrow transplantation (BMT). In TBI, the dose calculation is based on dosimetry using a phantom. We measured the basic dose with a phantom using a 10 MV X-rays. We confirmed the accuracy of the dose calculation performed in our facilities and investigated a method of more accurate dosimetry. We measured the variation in dose according to the size of the phantom and the depth using a tough water phantom, and examined the difference in TMR according to SCD, field size, and size of the phantom. Consequently, the dose has been changed regardless of the size of the phantom at larger than 80 x 30 x 30 cm{sup 3}, and it is about 1% larger than 30 x 30 x 30 cm{sup 3}. Also TMR has changed according to various conditions, including the size of the phantom, field size, and SCD. Therefore, it was found that dosimetry using the 30 x 30 x 30 cm{sup 3} phantom leads to underestimation in dose calculation, and there is no difference in dose between the field size of 151.5 x 160 cm{sup 2} and 151.5 x 80 cm{sup 2}. It is also necessary to consider the effect of the vertical size of the phantom. (author)

  3. [Phantom holder of CT couch].

    Science.gov (United States)

    Zhang, Ruixia; Zhan, Hongyu; Wang, Di

    2014-03-01

    This article describes a phantom holder in CT couch which adjusted easily and accurately, installed easily. The holder mainly include removing and locking equipment between phantom holder and table top, move horizontally equipment between left and right, rotating equipment between left and right. After holder and table top fixed one part, holder with phantom can move horizontally, front and back, rotate between left and right in a small angle, in order to make operator test phantoms accurately and easily. At the same time, this phantom holder realized free adjustment after first adjustments, which shortened operator work time.

  4. Tissue-like phantoms

    Science.gov (United States)

    Frangioni, John V.; De Grand, Alec M.

    2007-10-30

    The invention is based, in part, on the discovery that by combining certain components one can generate a tissue-like phantom that mimics any desired tissue, is simple and inexpensive to prepare, and is stable over many weeks or months. In addition, new multi-modal imaging objects (e.g., beads) can be inserted into the phantoms to mimic tissue pathologies, such as cancer, or merely to serve as calibration standards. These objects can be imaged using one, two, or more (e.g., four) different imaging modalities (e.g., x-ray computed tomography (CT), positron emission tomography (PET), single photon emission computed tomography (SPECT), and near-infrared (NIR) fluorescence) simultaneously.

  5. The Phantom SPH code

    Science.gov (United States)

    Price, Daniel; Wurster, James; Nixon, Chris

    2016-05-01

    I will present the capabilities of the Phantom SPH code for global simulations of dust and gas in protoplanetary discs. I will present our new algorithms for simulating both small and large grains in discs, as well as our progress towards simulating evolving grain populations and coupling with radiation. Finally, I will discuss our recent applications to HL Tau and the physics of dust gap opening.

  6. In vitro biological effectiveness of JRR-4 epithermal neutron beam. Experiment under free air beam and in water phantom. Cooperative research

    CERN Document Server

    Yamamoto, T; Horiguchi, Y; Kishi, T; Kumada, H; Matsumura, A; Nose, T; Torii, Y; Yamamoto, K

    2002-01-01

    The surviving curve and the biological effectiveness factor of dose components generated in boron neutron capture therapy (BNCT) were separately determined in neutron beams at Japan Research Reactor No.4. Surviving fraction of V79 Chinese hamster cell with or without sup 1 sup 0 B was obtained using an epithermal neutron beam (ENB), a mixed thermal-epithermal neutron beam (TNB-1), and a thermal neutron beam (TNB-2), which were used or planned to use for BNCT clinical trial. The cell killing effect of these neutron beams with or without the presence of sup 1 sup 0 B depended highly on the neutron beam used, according to the epithermal and fast neutron content in the beam. The biological effectiveness factor values of the boron capture reaction for ENB, TNB-1 and TNB-2 were 3.99+-0.24, 3.04+-0.19 and 1.43+-0.08, respectively. The biological effectiveness factor values of the high-LET dose components based on the hydrogen recoils and the nitrogen capture reaction were 2.50+-0.32, 2.34+-0.30 and 2.17+-0.28 for EN...

  7. Optimized generation of high resolution breast anthropomorphic software phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Pokrajac, David D.; Maidment, Andrew D. A.; Bakic, Predrag R. [Computer and Information Sciences Department, Delaware State University, Dover, Delaware 19901 (United States); Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2012-04-15

    Purpose: The authors present an efficient method for generating anthropomorphic software breast phantoms with high spatial resolution. Employing the same region growing principles as in their previous algorithm for breast anatomy simulation, the present method has been optimized for computational complexity to allow for fast generation of the large number of phantoms required in virtual clinical trials of breast imaging. Methods: The new breast anatomy simulation method performs a direct calculation of the Cooper's ligaments (i.e., the borders between simulated adipose compartments). The calculation corresponds to quadratic decision boundaries of a maximum a posteriori classifier. The method is multiscale due to the use of octree-based recursive partitioning of the phantom volume. The method also provides user-control of the thickness of the simulated Cooper's ligaments and skin. Results: Using the proposed method, the authors have generated phantoms with voxel size in the range of (25-1000 {mu}m){sup 3}/voxel. The power regression of the simulation time as a function of the reciprocal voxel size yielded a log-log slope of 1.95 (compared to a slope of 4.53 of our previous region growing algorithm). Conclusions: A new algorithm for computer simulation of breast anatomy has been proposed that allows for fast generation of high resolution anthropomorphic software phantoms.

  8. Copolymer-in-oil phantom materials for elastography.

    Science.gov (United States)

    Oudry, J; Bastard, C; Miette, V; Willinger, R; Sandrin, L

    2009-07-01

    Phantoms that mimic mechanical and acoustic properties of soft biological tissues are essential to elasticity imaging investigation and to elastography device characterization. Several materials including agar/gelatin, polyvinyl alcohol and polyacrylamide gels have been used successfully in the past to produce tissue phantoms, as reported in the literature. However, it is difficult to find a phantom material with a wide range of stiffness, good stability over time and high resistance to rupture. We aim at developing and testing a new copolymer-in-oil phantom material for elastography. The phantom is composed of a mixture of copolymer, mineral oil and additives for acoustic scattering. The mechanical properties of phantoms were evaluated with a mechanical test instrument and an ultrasound-based elastography technique. The acoustic properties were investigated using a through-transmission water-substituting method. We showed that copolymer-in-oil phantoms are stable over time. Their mechanical and acoustic properties mimic those of most soft tissues: the Young's modulus ranges from 2.2-150 kPa, the attenuation coefficient from 0.4-4.0 dB.cm(-1) and the ultrasound speed from 1420-1464 m/s. Their density is equal to 0.90 +/- 0.04 g/cm3. The results suggest that copolymer-in-oil phantoms are attractive materials for elastography.

  9. Positive cooperativity in substrate binding of human prostatic acid phosphatase entrapped in AOT-isooctane-water reverse micelles.

    Science.gov (United States)

    Luchter-Wasylewska, Ewa; Iciek, Małgorzata

    2004-05-15

    The kinetics of 1-naphthyl phosphate and phenyl phosphate hydrolysis, catalyzed by human prostatic acid phosphatase (PAP) entrapped in AOT-isooctane-water reverse micelles, has been studied over surfactant hydration degree (w0) range 5 to 35. Continuous spectrophotometric acid phosphatase assays, previously prepared, were employed. PAP was catalytically active over the whole w0 studied range. In order to determine steady-state reaction constants the experimental data were fitted to Hill rate equation. Positive cooperativity in substrate binding was observed, as it was earlier found in aqueous solutions. The extent of cooperativity (expressed as the value of the Hill cooperation coefficient h) increased from 1 to 4, when the micellar water-pool size was growing, at fixed enzyme concentration. In the plots of catalytic activity (kcat) versus w0, the maxima have been found at w0=10 (pH 5.6) and 23 (pH 3.8). It is suggested that catalytically active monomeric and dimeric PAP forms are entrapped in reverse micelles of w0=10 and 23, respectively.

  10. Phantom breast syndrome

    Directory of Open Access Journals (Sweden)

    Ramesh

    2009-01-01

    Full Text Available Phantom breast syndrome is a type of condition in which patients have a sensation of residual breast tissue and can include both non-painful sensations as well as phantom breast pain. The incidence varies in different studies, ranging from approximately 30% to as high as 80% of patients after mastectomy. It seriously affects quality of life through the combined impact of physical disability and emotional distress. The breast cancer incidence rate in India as well as Western countries has risen in recent years while survival rates have improved; this has effectively increased the number of women for whom post-treatment quality of life is important. In this context, chronic pain following treatment for breast cancer surgery is a significantly under-recognized and under-treated problem. Various types of chronic neuropathic pain may arise following breast cancer surgery due to surgical trauma. The cause of these syndromes is damage to various nerves during surgery. There are a number of assumed factors causing or perpetuating persistent neuropathic pain after breast cancer surgery. Most well-established risk factors for developing phantom breast pain and other related neuropathic pain syndromes are severe acute postoperative pain and greater postoperative use of analgesics. Based upon current evidence, the goals of prophylactic strategies could first target optimal peri-operative pain control and minimizing damage to nerves during surgery. There is some evidence that chronic pain and sensory abnormalities do decrease over time. The main group of oral medications studied includes anti-depressants, anticonvulsants, opioids, N-methyl-D-asparate receptor antagonists, mexilitine, topical lidocaine, cannabinoids, topical capsaicin and glysine antagonists. Neuromodulation techniques such as motor cortex stimulation, spinal cord stimulation, and intrathecal drug therapies have been used to treat various neuropathic pain syndromes.

  11. Phantom stars and topology change

    CERN Document Server

    DeBenedictis, Andrew; Lobo, Francisco S N

    2008-01-01

    In this work, we consider time-dependent dark energy star models, with an evolving parameter $\\omega$ crossing the phantom divide, $\\omega=-1$. Once in the phantom regime, the null energy condition is violated, which physically implies that the negative radial pressure exceeds the energy density. Therefore, an enormous negative pressure in the center may, in principle, imply a topology change, consequently opening up a tunnel and converting the dark energy star into a wormhole. The criteria for this topology change are discussed, in particular, we consider the Morse Index analysis and a Casimir energy approach involving quasi-local energy difference calculations that may reflect or measure the occurrence of a topology change. We denote these exotic geometries consisting of dark energy stars (in the phantom regime) and phantom wormholes as phantom stars. The final product of this topological change, namely, phantom wormholes, have far-reaching physical and cosmological implications, as in addition to being use...

  12. Multi-Modality Phantom Development

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Jennifer S.; Peng, Qiyu; Moses, William W.

    2009-03-20

    Multi-modality imaging has an increasing role in the diagnosis and treatment of a large number of diseases, particularly if both functional and anatomical information are acquired and accurately co-registered. Hence, there is a resulting need for multi modality phantoms in order to validate image co-registration and calibrate the imaging systems. We present our PET-ultrasound phantom development, including PET and ultrasound images of a simple prostate phantom. We use agar and gelatin mixed with a radioactive solution. We also present our development of custom multi-modality phantoms that are compatible with PET, transrectal ultrasound (TRUS), MRI and CT imaging. We describe both our selection of tissue mimicking materials and phantom construction procedures. These custom PET-TRUS-CT-MRI prostate phantoms use agargelatin radioactive mixtures with additional contrast agents and preservatives. We show multi-modality images of these custom prostate phantoms, as well as discuss phantom construction alternatives. Although we are currently focused on prostate imaging, this phantom development is applicable to many multi-modality imaging applications.

  13. Thermal human phantom for testing of millimeter wave cameras

    Science.gov (United States)

    Palka, Norbert; Ryniec, Radoslaw; Piszczek, Marek; Szustakowski, Mieczyslaw; Zyczkowski, Marek; Kowalski, Marcin

    2012-06-01

    Screening cameras working in millimetre band gain more and more interest among security society mainly due to their capability of finding items hidden under clothes. Performance of commercially available passive cameras is still limited due to not sufficient resolution and contrast in comparison to other wavelengths (visible or infrared range). Testing of such cameras usually requires some persons carrying guns, bombs or knives. Such persons can have different clothes or body temperature, what makes the measurements even more ambiguous. To avoid such situations we built a moving phantom of human body. The phantom consists of a polystyrene manikin which is covered with a number of small pipes with water. Pipes were next coated with a silicone "skin". The veins (pipes) are filled with water heated up to 37 C degrees to obtain the same temperature as human body. The phantom is made of non-metallic materials and is placed on a moving wirelessly-controlled platform with four wheels. The phantom can be dressed with a set of ordinary clothes and can be equipped with some dangerous (guns, bombs) and non-dangerous items. For tests we used a passive commercially available camera TS4 from ThruVision Systems Ltd. operating at 250 GHz. We compared the images taken from phantom and a man and we obtained good similarity both for naked as well as dressed man/phantom case. We also tested the phantom with different sets of clothes and hidden items and we got good conformity with persons.

  14. Climate change and adaptive water manangement through tansboundary cooperation: the case of the Guadiana River Basin

    NARCIS (Netherlands)

    Cots, F.; Tabara, J.D.; Werners, S.E.; McEvoy, D.

    2007-01-01

    In the EU, regions are acquiring greater decisional powers in the recent years. However, the ‘new regions’ do not longer correspond to the divisions that once were useful to the particular goals of the old nation-states, but are now created upon other new cooperation goals, including environment and

  15. 75 FR 77821 - Agricultural Water Enhancement Program and Cooperative Conservation Partnership Initiative

    Science.gov (United States)

    2010-12-14

    ... agreements with the Natural Resources Conservation Service (NRCS) through either the Agricultural Water... concerns to be addressed, and specifically what water conservation resource issues and water quality... long-term conservation of surface and ground water or water quality improvement and related...

  16. The Phantom of Liberty

    DEFF Research Database (Denmark)

    One of the few things we have in common in contemporary society is the future of our children. But it seems that even the “we” of childhood, of learning and free play, has turned into a common ground for instrumentalization and competition. Today, the pedagogical paradox—Kant’s meditation...... on the paradox that the subject’s predisposition for freedom must be learned—is increasingly lost in governmental obsession about the efficiency of education and schooling. From another perspective, artists are addressing questions of childhood, play, and pedagogy. What ideological and moral transformations......? These are some of the questions addressed by The Phantom of Liberty, which sets out to reestablish a social and aesthetic dialogue between visual art and psychology, philosophy, pedagogy, and critical journalism....

  17. [Therapy of phantom limb pain].

    Science.gov (United States)

    Schwarzer, Andreas; Zenz, Michael; Maier, Christoph

    2009-03-01

    About 80 % of all extremity amputations suffer from phantom limb pain following the operation. In this context, it is important to differentiate between painful phantom limb sensations, non-painful phantom limb sensations and residual limb pain. The pathophysiology of phantom limb pain is not fully understood. Current research findings ascribe a major pathophysiological role to cortical changes as well as a disturbed body perception. Peripheral and spinal mechanisms appear less relevant in the development of phantom limb pain. An essential part of the therapy is the pharmacological treatment with antidepressants, anticonvulsives and opioids. Another significant aspect of therapy is senso-motory training, important to mention here would be mirror therapy, lateralisation and motor imaging. In case of an elective amputation, an epidural or axiliar plexus catheter should be considered prior to the amputation. The perioperative treatment with ketamine is debated.

  18. Multi-Agent Many-Objective Robust Decision Making: Supporting Cooperative Regional Water Portfolio Planning in the Eastern United States

    Science.gov (United States)

    Herman, J. D.; Zeff, H. B.; Reed, P. M.; Characklis, G. W.

    2013-12-01

    In the Eastern United States, water infrastructure and institutional frameworks have evolved in a historically water-rich environment. However, large regional droughts over the past decade combined with continuing population growth have marked a transition to a state of water scarcity, for which current planning paradigms are ill-suited. Significant opportunities exist to improve the efficiency of water infrastructure via regional coordination, namely, regional 'portfolios' of water-related assets such as reservoirs, conveyance, conservation measures, and transfer agreements. Regional coordination offers the potential to improve reliability, cost, and environmental impact in the expected future state of the world, and, with informed planning, to improve robustness to future uncertainty. In support of this challenge, this study advances a multi-agent many-objective robust decision making (multi-agent MORDM) framework that blends novel computational search and uncertainty analysis tools to discover flexible, robust regional portfolios. Our multi-agent MORDM framework is demonstrated for four water utilities in the Research Triangle region of North Carolina, USA. The utilities supply nearly two million customers and have the ability to interact with one another via transfer agreements and shared infrastructure. We show that strategies for this region which are Pareto-optimal in the expected future state of the world remain vulnerable to performance degradation under alternative scenarios of deeply uncertain hydrologic and economic factors. We then apply the Patient Rule Induction Method (PRIM) to identify which of these uncertain factors drives the individual and collective vulnerabilities for the four cooperating utilities. Our results indicate that clear multi-agent tradeoffs emerge for attaining robustness across the utilities. Furthermore, the key factor identified for improving the robustness of the region's water supply is cooperative demand reduction. This type

  19. Acrylonitrile Butadiene Styrene (ABS) plastic based low cost tissue equivalent phantom for verification dosimetry in IMRT.

    Science.gov (United States)

    Kumar, Rajesh; Sharma, S D; Deshpande, Sudesh; Ghadi, Yogesh; Shaiju, V S; Amols, H I; Mayya, Y S

    2009-12-17

    A novel IMRT phantom was designed and fabricated using Acrylonitrile Butadiene Styrene (ABS) plastic. Physical properties of ABS plastic related to radiation interaction and dosimetry were compared with commonly available phantom materials for dose measurements in radiotherapy. The ABS IMRT phantom has provisions to hold various types of detectors such as ion chambers, radiographic/radiochromic films, TLDs, MOSFETs, and gel dosimeters. The measurements related to pre-treatment dose verification in IMRT of carcinoma prostate were carried out using ABS and Scanditronics-Wellhoffer RW3 IMRT phantoms for five different cases. Point dose data were acquired using ionization chamber and TLD discs while Gafchromic EBT and radiographic EDR2 films were used for generating 2-D dose distributions. Treatment planning system (TPS) calculated and measured doses in ABS plastic and RW3 IMRT phantom were in agreement within +/-2%. The dose values at a point in a given patient acquired using ABS and RW3 phantoms were found comparable within 1%. Fluence maps and dose distributions of these patients generated by TPS and measured in ABS IMRT phantom were also found comparable both numerically and spatially. This study indicates that ABS plastic IMRT phantom is a tissue equivalent phantom and dosimetrically it is similar to solid/plastic water IMRT phantoms. Though this material is demonstrated for IMRT dose verification but it can be used as a tissue equivalent phantom material for other dosimetry purposes in radiotherapy.

  20. A cooled water-irrigated intraesophageal balloon to prevent thermal injury during cardiac ablation: experimental study based on an agar phantom

    Energy Technology Data Exchange (ETDEWEB)

    Lequerica, Juan L [Cardiac Research Laboratory, Instituto de Biomedicina, Spanish Council for Scientific Research (CSIC), Valencia (Spain); Berjano, Enrique J [Institute for Research and Innovation on Bioengineering, Valencia Polytechnic University, Valencia (Spain); Herrero, Maria [Cardiac Research Laboratory, Instituto de Biomedicina, Spanish Council for Scientific Research (CSIC), Valencia (Spain); Melecio, Lemuel [Cardiac Research Laboratory, Instituto de Biomedicina, Spanish Council for Scientific Research (CSIC), Valencia (Spain); Hornero, Fernando [Department of Cardiac Surgery, Consorcio Hospital General Universitario, Valencia (Spain)

    2008-02-21

    A great deal of current research is directed to finding a way to minimize thermal injury in the esophagus during radiofrequency catheter ablation of the atrium. A recent clinical study employing a cooling intraesophageal balloon reported a reduction of the temperature in the esophageal lumen. However, it could not be determined whether the deeper muscular layer of the esophagus was cooled enough to prevent injury. We built a model based on an agar phantom in order to experimentally study the thermal behavior of this balloon by measuring the temperature not only on the balloon, but also at a hypothetical point between the esophageal lumen and myocardium (2 mm distant). Controlled temperature (55 {sup 0}C) ablations were conducted for 120 s. The results showed that (1) the cooling balloon provides a reduction in the final temperature reached, both on the balloon surface and at a distance of 2 mm; (2) coolant temperature has a significant effect on the temperature measured at 2 mm from the esophageal lumen (it has a less effect on the temperature measured on the balloon surface) and (3) the pre-cooling period has a significant effect on the temperature measured on the balloon surface (the effect on the temperature measured 2 mm away is small). The results were in good agreement with those obtained in a previous clinical study. The study suggests that the cooling balloon gives thermal protection to the esophagus when a minimum pre-cooling period of 2 min is programmed at a coolant temperature of 5 deg. C or less. (note)

  1. Development of neonate phantom for estimating medical exposure

    Energy Technology Data Exchange (ETDEWEB)

    Akahane, K.; Kai, M.; Kusama, T. [Oita Univ. of Nursing and Health Sciences, Oita (Japan); Mitarai, T.; Ono, K.; Hada, M.; Ninomiya, H.; Kato, Y. [Oita Prefectural Hospital, Oita (Japan)

    2000-05-01

    The distribution and volume ratio of radiation sensitive organs such as red bone marrow are different between neonates and adults. In addition, the body sizes of neonates in NICU are smaller than normal neonates. Consequently, it is important to estimate a neonatal dose for X-ray examinations in NICU. However, there are few reports on quantitative estimates of measured or mathematically calculated doses for neonatal X-ray examinations. In order to estimate their dose, we made a physical neonatal phantom and estimated its dose using both measurement and calculation methods. In determining the phantom geometry, the body sizes were measured for neonates of NICU in Oita prefectural hospital. As body parameters, weights, heights and trunk sizes were obtained. The weight of phantom was determined to be 2000 g based on these data. The height of the phantom is 43.5 cm, and the trunk width is determined to be 9.5 cm. The whole shape was expressed with rectangular solids without bone region to avoid the difficulties on phantom construction and calculations. The height and other body size parameters were calculated as a function of body weight, which were determined as regression lines on these data. The weights of lungs were calculated using NIRS-M-115, and the positions were determined according to anatomical geometry. The components of the phantom were soft tissue and lung, and tough water and tough lung phantoms were selected as materials of the phantom. For the purpose of the dose measurement, the phantom was located in the incubator of NICU, and exposed under 4 kinds of the conditions of ordinary X-ray examination, which were for chest, combined abdomen-chest, abdomen and head radiographs using a portable X-ray machine. A film-badge was put on the center of exposed area for each examination, and measured entrance surface dose of the phantom. The glass dosimeters were also used. The measured doses of chest, combined abdomen-chest and abdomen were 0.1-0.12 mSv. The Monte

  2. Atypical Odontalgia (Phantom Tooth Pain)

    Science.gov (United States)

    ... Odontalgia Atypical odontalgia, also known as atypical facial pain, phantom tooth pain, or neuropathic orofacial pain, is characterized by chronic pain in a tooth or teeth, or in a site where teeth ...

  3. Material-specific Conversion Factors for Different Solid Phantoms Used in the Dosimetry of Different Brachytherapy Sources

    Directory of Open Access Journals (Sweden)

    Sedigheh Sina

    2015-07-01

    Full Text Available Introduction Based on Task Group No. 43 (TG-43U1 recommendations, water phantom is proposed as a reference phantom for the dosimetry of brachytherapy sources. The experimental determination of TG-43 parameters is usually performed in water-equivalent solid phantoms. The purpose of this study was to determine the conversion factors for equalizing solid phantoms to water. Materials and Methods TG-43 parameters of low- and high-energy brachytherapy sources (i.e., Pd-103, I-125 and Cs-137 were obtained in different phantoms, using Monte Carlo simulations. The brachytherapy sources were simulated at the center of different phantoms including water, solid water, poly(methyl methacrylate, polystyrene and polyethylene. Dosimetric parameters such as dose rate constant, radial dose function and anisotropy function of each source were compared in different phantoms. Then, conversion factors were obtained to make phantom parameters equivalent to those of water. Results Polynomial coefficients of conversion factors were obtained for all sources to quantitatively compare g(r values in different phantom materials and the radial dose function in water. Conclusion Polynomial coefficients of conversion factors were obtained for all sources to quantitatively compare g(r values in different phantom materials and the radial dose function in water.

  4. Phantom pain after eye amputation.

    Science.gov (United States)

    Rasmussen, Marie L R; Prause, Jan U; Toft, Peter B

    2011-02-01

    To characterize the quality of phantom pain, its intensity and frequency following eye amputation. Possible triggers and relievers of phantom pain are investigated. The hospital database was searched using surgery codes for patients who received ocular evisceration, enucleation, orbital exenteration or secondary implantation of an orbital implant in the period between 1993 and 2003. A total of 267 patients were identified and invited to participate; of these, 173 agreed to participate. These patients' medical records were reviewed. A structured interview focusing on pain was conducted by a trained interviewer. Of the 173 patients in the study, 39 experienced phantom pain. The median age of patients who had experienced phantom pain was 45 years (range: 19-88). Follow-up time from eye amputation to participation in the investigation was 4 years (range: 2-46). Phantom pain was reported to be of three different qualities: (i) cutting, penetrating, gnawing or oppressive (n = 19); (ii) radiating, zapping or shooting (n = 8); (iii) superficial burning or stinging (n = 5); or a mixture of these different pain qualities (n = 7). The median intensity on a visual analogue scale, ranging from 0 to 100, was 36 (range: 1-89). One-third of the patients experienced phantom pain every day. Chilliness, windy weather and psychological stress/fatigue were the most commonly reported triggers for pain.   Phantom pain after eye amputation is relatively common. The pain appears to be similar to the phantom pain suffered by limb amputees. Patients should be informed about this potential complication before surgery. © 2010 The Authors. Acta Ophthalmologica © 2010 Acta Ophthalmologica Scandinavica Foundation.

  5. Strategies of the Poorest in Local Water Conflict and Cooperation - Evidence from Vietnam, Bolivia and Zambia

    NARCIS (Netherlands)

    Funder, M.; Bustamante Zenteno, R.R.; Cossio Rojas, V.; Huong, P.T.M.; Koppen, van B.; Mweemba, C.; Nyambe, L.; Phuong, L.T.T.; Skielboe, T.

    2012-01-01

    Media stories often speak of a future dominated by large-scale water wars. Rather less attention has been paid to the way water conflicts already play out at local levels and form part of people’s everyday lives. Based on case study studies from Vietnam, Bolivia and Zambia, this paper examines the s

  6. Co-operative agreements and the EU Water Framework Directive in conjunction with the Common Agricultural Policy

    Science.gov (United States)

    Heinz, I.

    2008-05-01

    This paper discusses the significance of voluntary arrangements for the water and agricultural policies in the European Union. The current implementation of the European Water Framework Directive (WFD) and the reform of the Common Agricultural Policy (CAP) require new approaches in water management. As many case studies have shown, co-operative agreements (CAs) between water companies, farmers and authorities can help to reduce environmental pressures on water bodies. The main reasons for that are: i) water companies are ready to advise and financially support farmers in changing production methods; ii) changes of farming practices are tailored to the site-specific requirements; iii) farmers and water companies are interested in minimising the costs and environmental pressures as they benefit, for example, from modernization of farming methods, and reductions in cost of water treatment, and iv) voluntarily agreed commitments to change farming practices are often stricter than statutory rules. Moreover, precautionary rather than remedial measures are preferred. Tackling diffuse pollution is one of the main concerns of the WFD. CAs can enhance the cost-effectiveness of actions within the programmes of measures so that good water status is achieved by 2015. In CAs all relevant stakeholders, located in catchment areas of agricultural usage, can be involved. Thus, they can help to foster integrated water resources management. In particular, disproportionate costs of changing farming practices can be identified. With regard to the recent CAP reform, financial support for farmers will be linked to compliance with environmental standards and further commitments. This concerns both direct payments and agri-environmental programmes. The experience gained in CAs can provide information on best agricultural practices. Informed farmers are more ready to meet environmental requirements. Because CAs implement the most cost-effective changes in farming practice, it can be assumed

  7. Co-operative agreements and the EU Water Framework Directive in conjunction with the Common Agricultural Policy

    Directory of Open Access Journals (Sweden)

    I. Heinz

    2007-06-01

    Full Text Available This paper discusses the significance of voluntary arrangements for the water and agricultural policies in the European Union. The current implementation of the European Water Framework Directive (WFD and the reform of the Common Agricultural Policy (CAP require new approaches in water management. As many case studies have shown, co-operative agreements (CAs between water companies, farmers and authorities can help to reduce environmental pressures on water bodies. The main reasons for that are: i water companies are ready to advise and financially support farmers in changing production methods; ii changes of farming practices are tailored to the site-specific requirements; iii farmers and water companies are interested in minimising the costs and environmental pressures as they benefit, for example, from modernization of farming methods, and reductions in cost of water treatment, and iv voluntarily agreed commitments to change farming practices are often stricter than statutory rules. Moreover, precautionary rather than remedial measures are preferred. Tackling diffuse pollution is one of the main concerns of the WFD. CAs can enhance the cost-effectiveness of actions within the programmes of measures so that good water status is achieved by 2015. In CAs all relevant stakeholders, located in catchment areas of agricultural usage, can be involved. Thus, they can help to foster integrated water resources management. In particular, disproportionate costs of changing farming practices can be identified. With regard to the recent CAP reform, financial support for farmers will be linked to compliance with environmental standards and further commitments. This concerns both direct payments and agri-environmental programmes. The experience gained in CAs can provide information on best agricultural practices. Informed farmers are more ready to meet environmental requirements. Because CAs implement the most cost-effective changes in farming practice, it

  8. Co-operative agreements and the EU Water Framework Directive in conjunction with the Common Agricultural Policy

    Directory of Open Access Journals (Sweden)

    I. Heinz

    2008-05-01

    Full Text Available This paper discusses the significance of voluntary arrangements for the water and agricultural policies in the European Union. The current implementation of the European Water Framework Directive (WFD and the reform of the Common Agricultural Policy (CAP require new approaches in water management. As many case studies have shown, co-operative agreements (CAs between water companies, farmers and authorities can help to reduce environmental pressures on water bodies. The main reasons for that are: i water companies are ready to advise and financially support farmers in changing production methods; ii changes of farming practices are tailored to the site-specific requirements; iii farmers and water companies are interested in minimising the costs and environmental pressures as they benefit, for example, from modernization of farming methods, and reductions in cost of water treatment, and iv voluntarily agreed commitments to change farming practices are often stricter than statutory rules. Moreover, precautionary rather than remedial measures are preferred. Tackling diffuse pollution is one of the main concerns of the WFD. CAs can enhance the cost-effectiveness of actions within the programmes of measures so that good water status is achieved by 2015. In CAs all relevant stakeholders, located in catchment areas of agricultural usage, can be involved. Thus, they can help to foster integrated water resources management. In particular, disproportionate costs of changing farming practices can be identified. With regard to the recent CAP reform, financial support for farmers will be linked to compliance with environmental standards and further commitments. This concerns both direct payments and agri-environmental programmes. The experience gained in CAs can provide information on best agricultural practices. Informed farmers are more ready to meet environmental requirements. Because CAs implement the most cost-effective changes in farming practice, it

  9. Organosilicon phantom for photoacoustic imaging.

    Science.gov (United States)

    Avigo, Cinzia; Di Lascio, Nicole; Armanetti, Paolo; Kusmic, Claudia; Cavigli, Lucia; Ratto, Fulvio; Meucci, Sandro; Masciullo, Cecilia; Cecchini, Marco; Pini, Roberto; Faita, Francesco; Menichetti, Luca

    2015-04-01

    Photoacoustic imaging is an emerging technique. Although commercially available photoacoustic imaging systems currently exist, the technology is still in its infancy. Therefore, the design of stable phantoms is essential to achieve semiquantitative evaluation of the performance of a photoacoustic system and can help optimize the properties of contrast agents. We designed and developed a polydimethylsiloxane (PDMS) phantom with exceptionally fine geometry; the phantom was tested using photoacoustic experiments loaded with the standard indocyanine green dye and compared to an agar phantom pattern through polyethylene glycol-gold nanorods. The linearity of the photoacoustic signal with the nanoparticle number was assessed. The signal-tonoiseratio and contrast were employed as image quality parameters, and enhancements of up to 50 and up to 300%, respectively, were measured with the PDMS phantom with respect to the agar one. A tissue-mimicking (TM)-PDMS was prepared by adding TiO2 and India ink; photoacoustic tests were performed in order to compare the signal generated by the TM-PDMS and the biological tissue. The PDMS phantom can become a particularly promising tool in the field of photoacoustics for the evaluation of the performance of a PA system and as a model of the structure of vascularized soft tissues.

  10. Cooperative hydration effect causes thermal unfolding of proteins and water activity plays a key role in protein stability in solutions.

    Science.gov (United States)

    Miyawaki, Osato; Dozen, Michiko; Hirota, Kaede

    2016-08-01

    The protein unfolding process observed in a narrow temperature range was clearly explained by evaluating the small difference in the enthalpy of hydrogen-bonding between amino acid residues and the hydration of amino acid residue separately. In aqueous solutions, the effect of cosolute on the protein stability is primarily dependent on water activity, aw, the role of which has been long neglected in the literature. The effect of aw on protein stability works as a power law so that a small change in aw is amplified substantially through the cooperative hydration effect. In the present approach, the role of hydrophobic interaction stands behind. This affects protein stability indirectly through the change in solution structure caused by the existence of cosolute.

  11. Water as a Source of Cooperation or Conflict in the Middle East,

    Science.gov (United States)

    1984-05-14

    Times, October 17, 1983, p. 11. Graham-Brown, Sarah "Water - How Israeli Policies Hurt West Bank Arabs" Arab RegP_ . May 23, 1979 Gutman, Emanuel and...1 2Lagd . Economic Review Of The Arab World. 3-0L1, MAa .. -4 prl.02 176-177, "Water, .. irc Ao S .Qf Life, Impact Of Science On Society. W Le Pays des

  12. Evaluation of thermoluminescent dosimeters using water equivalent phantoms for application in clinical electrons beams dosimetry; Avaliacao de dosimetros termoluminescentes empregando objetos simuladores equivalentes a agua para aplicacao na dosimetria de feixes clinicos de eletrons

    Energy Technology Data Exchange (ETDEWEB)

    Bravim, Amanda

    2010-07-01

    The dosimetry in Radiotherapy provides the calibration of the radiation beam as well as the quality control of the dose in the clinical routine. Its main objective is to determine with greater accuracy the dose absorbed by the tumor. This study aimed to evaluate the behavior of three thermoluminescent dosimeters for the clinical electron beam dosimetry. The performance of the calcium sulfate detector doped with dysprosium (CaSO{sub 4}: Dy) produced by IPEN was compared with two dosimeters commercially available by Harshaw. Both are named TLD-100, however they differ in their dimensions. The dosimeters were evaluated using water, solid water (RMI-457) and PMMA phantoms in different exposure fields for 4, 6, 9, 12 and 16 MeV electron beam energies. It was also performed measurements in photon beams of 6 and 15 MV (2 and 5 MeV) only for comparison. The dose-response curves were obtained for the {sup 60}Co gamma radiation in air and under conditions of electronic equilibrium, both for clinical beam of photons and electrons in maximum dose depths. The sensitivity, reproducibility, intrinsic efficiency and energy dependence response of dosimeters were studied. The CaSO{sub 4}: Dy showed the same behavior of TLD-100, demonstrating only an advantage in the sensitivity to the beams and radiation doses studied. Thus, the dosimeter produced by IPEN can be considered a new alternative for dosimetry in Radiotherapy departments. (author)

  13. A Novel Simple Phantom for Verifying the Dose of Radiation Therapy

    Directory of Open Access Journals (Sweden)

    J. H. Lee

    2015-01-01

    Full Text Available A standard protocol of dosimetric measurements is used by the organizations responsible for verifying that the doses delivered in radiation-therapy institutions are within authorized limits. This study evaluated a self-designed simple auditing phantom for use in verifying the dose of radiation therapy; the phantom design, dose audit system, and clinical tests are described. Thermoluminescent dosimeters (TLDs were used as postal dosimeters, and mailable phantoms were produced for use in postal audits. Correction factors are important for converting TLD readout values from phantoms into the absorbed dose in water. The phantom scatter correction factor was used to quantify the difference in the scattered dose between a solid water phantom and homemade phantoms; its value ranged from 1.084 to 1.031. The energy-dependence correction factor was used to compare the TLD readout of the unit dose irradiated by audit beam energies with 60Co in the solid water phantom; its value was 0.99 to 1.01. The setup-condition factor was used to correct for differences in dose-output calibration conditions. Clinical tests of the device calibrating the dose output revealed that the dose deviation was within 3%. Therefore, our homemade phantoms and dosimetric system can be applied for accurately verifying the doses applied in radiation-therapy institutions.

  14. Removal of cyclops in pre-oxidizing cooperation water treatment process

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Zooplankton cyclops propagates profusely in waterbody, cannot be effectively inactivated by conventional disinfection process, and becomes a troublesome drinking water treatment problem. In this work, the qualitative and quantitative experimental studies were carried out on inactivation of zooplankton cyclops using oxidants, such as chlorine (Cl2), chlorine dioxide (ClO2), ozone (O3), hydrogen peroxide (H2O2), ozone/hydrogen peroxide (O3/H2O2), chloramines (Cl2-NH3) and potassium permanganate (KMnO4). The influences of various factors include different oxidant dosages, organic substance contents and pH values. The results showed that currently available oxidants used all might inactivate cyclops in some extent. According to the experimental results, chlorine dioxide, ozone, ozone/hydrogen peroxide and chloramines can be selected as effective oxidants for inactivating cyclops because of their strong inactivation abilities. Then the synergic removal effects on cyclops with ozone,ozone/hydrogen peroxide pre-oxidation followed by conventional water treatment processes were investigated. The results showed that ozone and ozone/hydrogen peroxide pre-oxidation can inactivate cyclops effectively, which then can be removed thoroughly by conventional water treatment processes. Cyclops cannot appear in water after filtration with 1.65 mg/L of ozone and 6 mg/L of hydrogen peroxide, with the inactivation rate being 62% before conventional water treatment processes. Cyclops cannot appear in water after filtration with 1.8 mg/L of ozone, with the inactivation rate being 50% before conventional water treatment processes. For different oxidants, when removal rate was the best, the inactivation rate was not the same. These results may provide reference and model for actual waterworks.

  15. Sustainability of Water Resources in the Upstream Watershed- Based Community Engagement and Multistakeholder Cooperation

    Science.gov (United States)

    Brotosusilo, Agus; Utari, Dyah; Agung Satria, Afrizal

    2016-02-01

    The communities engagement become the backbone of the conservation in the Citanduy upstream watershed. It functioning as a major deal and the first one in keeping his own Watershed. This paper based on Community Engagement Grants (CEGs). Program Society-based empowerment approach is also emphasized in the viewpoint of environmental law that is useful to set governance and sanctions in watershed management. The type of activity to be undertaken are the expansion of awareness programs communities of the existence and condition of the watershed Citanduy, the formation of a cadre of conservationists environment that is primarily directed to children and women, the institutionalization of customary law environment, and afforestation by planting 100,000 prolific trees, tree conservationists, and Sunda endemic tree in the land surrounding the watershed upstream Citanduy. The Program involves several partners and stakeholders who helped in substance and operational support activities in the field.. Result of program shows that Community Engagement Grants need cooperation among stakeholders by positioning the community as main subject of changing, not as subject who does not understand their needs to change.

  16. Cooperation with respect to cleaning of an international water body with stochastic environmental damage: the case of the Baltic Sea

    NARCIS (Netherlands)

    Folmer, H.; Gren, I.M.

    2003-01-01

    Cooperation with respect to international environmental problems is often hampered by the fact that some countries incur net losses from cooperation. Moreover, uncertainty of damage due to variations in pollution loads is usually ignored in analyses of international environmental cooperation. This p

  17. SimBasin: A serious gaming framework for integrated and cooperative decision-making in water management

    Science.gov (United States)

    Angarita, H.; Craven, J.; Caggiano, F.; Corzo, G.

    2016-12-01

    An Integrated approach involving extensive stakeholder dialogue is widely advocated in sustainable water management. However, it requires a social learning process in which scientist and stakeholders become aware of the relationship between their own frames of reference and those of others, differences can be dealt with constructively, and shared ideas can be used to facilitate cooperation. Key obstacles in this process are heritage systems, attitudes and processes, factually wrong, incomplete or unshared mental models, and lack of science-policy dialogue (Pahl-Wostl et al., 2005) To overcome these barriers, a space is required which is free of heritage systems, where mental models can be safely and easily compared and corrected, and where scientists and policy-makers can come together. A "serious game" can serve as such a space - Serious games are games or simulations used to achieve an organizational or educational goal, and such games have already been used to facilitate stakeholder cooperation in the water management sector (Rusca et al., 2005). As well as bringing stakeholders together, they can be an accessible interface between scientific models and non-experts. Here we present SimBasin, a multiplayer serious game framework and development engine. The engine allows to easily create a simulated multiplayer basin management game using WEAP water resources modelling software (SEI, 1992-2015), to facilitate the communication of the complex, long term and wide range relationships between hydrologic, climate, and human systems present in river basins, and enable dialogue between policy-makers and scientists. Different games have been created using the Sim-Basin engine and used in various contexts. Here are discussed experiences with stakeholders at a national forum in Bogotá, flood risk management agencies in the lower Magdalena River Basin in Colombia and with water professionals in Bangkok. The experience shows that the game is a useful tool for enabling

  18. Cooperative dynamics of didodecyldimethylammonium bromide / water / n-dodecane microemulsions: a dielectric relaxation study

    OpenAIRE

    Wachter, Wolfgang

    2008-01-01

    A systematic study of the dielectric relaxation spectra of W/O (water-in-oil) microemulsions composed of didodecyldimethylammonium bromide (DDAB), water (W) and n-dodecane (D) has been made over the whole stability region in the phase diagram and over a wide range of frequencies (0.005 < nu/GHz < 89) at 25 °C. The spectra were best described by a superposition of six or five Debye processes, respectively, depending on the position of the sample in the phase diagram. Process 1 at 40 ns can be ...

  19. CEDEX's supporting activities through the Cooperation fund for Water and Sanitation; Apoyo del CEDEX a las actuaciones del Fondo de cooperacion para Agua y Saneamiento

    Energy Technology Data Exchange (ETDEWEB)

    Rio Marrero, I. del

    2015-07-01

    This paper deals with the activities CEDEX has being doing since 2012, Giving Technical support to the cooperation fund for Water and Sanitation (Fondo de Cooperacion para Agua y Saneamiento-FCAS), of the Spanish Agency for International Development Cooperation. Throughout the document, the different activities carried out by the CEDEX up to now, are briefly described. They have mainly consisted in giving technical support during the formulation, review and monitoring of the tasks derived from the FCAS programs, capacity buildings, and preparing technical guides and recommendations concerning different subjects. The FCAS programs concerns water planning water supply and sanitation planning as well as water supply and sanitation (sewerage and wastewater treatment plants) construction projects. The paper ends up presenting a set of conclusions and lessons learned extracted from this period working for the FCAS, as well as the main courses of action projected for the future collaboration works. (Author)

  20. Consideration of fractal and ion-water cooperative interactions in aqueous Na2SO4 and K2SO4 solutions by dielectric relaxation spectroscopy

    Science.gov (United States)

    Liu, Shuang; Jia, Guo-zhu; Zhang, Shu

    2016-01-01

    This paper presents the analysis of the fractal and the ion-water cooperative interactions in aqueous Na2SO4 and K2SO4 solutions underlying the Cole-Cole symmetrical broadening and depicts the Cole-Cole relaxation process. Fractal analysis with α(ln(τ)) diagram from dielectric relaxation spectroscopy (DRS) draws a consistent microscopic picture of ion-water cooperative interactions in aqueous Na2SO4 and K2SO4 solutions. The density of the water molecules perturbed by ions in the hydration shell almost linearly increases with salt concentrations. The water molecules network perturbed by ions contributing to dielectric constant beyond the first hydration shell is obtained.

  1. To cooperate or not to cooperate

    DEFF Research Database (Denmark)

    Wessels, Josepha Ivanka

    To Cooperate or not to Cooperate...? discusses results of a research project to study the rehabilitation of 1500-year old water tunnels, so called "qanats", in Syria. Communities all over the world are using traditional technologies to extract drinkingwater, irrigate their lands and feed their li......To Cooperate or not to Cooperate...? discusses results of a research project to study the rehabilitation of 1500-year old water tunnels, so called "qanats", in Syria. Communities all over the world are using traditional technologies to extract drinkingwater, irrigate their lands and feed...... their livestock. But these often sustainable and ancient ways to make use of groundwater are in rapid decline worldwide. A research project started in 1999 to study the rehabilitation of 1500-year old water tunnels called "qanats"in Syria. To Cooperate or not to Cooperate...? discusses results and outcomes...... of this research project. The main objective of this research is to better understand the proces of collective maintenance of these ancient water tunnels. The study evaluates the social, cultural, political and environmental factors that have driven abandonment and decay of qanats in Syria. It tries to reconcile...

  2. Successful water quality monitoring: The right combination of intent, measurement, interpretation, and a cooperating ecosystem

    Science.gov (United States)

    Soballe, D.M.

    1998-01-01

    Water quality monitoring is invaluable to ensure compliance with regulations, detect trends or patterns, and advance ecological understanding. However, monitoring typically measures only a few characteristics in a small fraction of a large and complex system, and thus the information contained in monitoring data depends upon which features of the ecosystem are actually captured by the measurements. Difficulties arise when these data contain something other than intended, but this can be minimized if the purpose of the sampling is clear, and the sampling design, measurements, and data interpretations are all compatible with this purpose. The monitoring program and data interpretation must also be properly matched to the structure and functioning of the system. Obtaining this match is sometimes an iterative process that demands a close link between research and monitoring. This paper focuses on water quality monitoring that is intended to track trends in aquatic resources and advance ecological understanding. It includes examples from three monitoring programs and a simulation exercise that illustrate problems that arise when the information content of monitoring data differs from expectation. The examples show (1) how inconsistencies among, or lack of information about, the basic elements of a monitoring program (intent, design, measurement, interpretation, and the monitored system) can produce a systematic difference (bias) between monitoring measurements and sampling intent or interpretation, and (2) that bias is not just a statistical consideration, but an insidious problem that can undermine the scientific integrity of a monitoring program. Some general suggestions are provided and hopefully these examples will help those engaged in water quality monitoring to enhance and protect the value of their monitoring investment.

  3. Comparison of organic phantom recipes and characterization by time-resolved diffuse optical spectroscopy

    Science.gov (United States)

    Quarto, G.; Pifferi, A.; Bargigia, I.; Farina, A.; Cubeddu, R.; Taroni, P.

    2013-06-01

    Three recipes for tissue constituent-equivalent phantoms of water and lipids are presented. Nature phantoms are made using no emulsifying agent, but just a professional disperser, instead Agar and Triton phantoms are made using agar or Triton X-100, respectively, as agents to emulsify water and lipids. Different water-to-lipid ratios ranging from 30 to 70 percent by mass are proposed and tested. Optical characterization by time-resolved spectroscopy was performed in terms of optical properties, homogeneity, reproducibility and composition retrieval.

  4. Phantom pain : A sensitivity analysis

    NARCIS (Netherlands)

    Borsje, Susanne; Bosmans, JC; Van der Schans, CP; Geertzen, JHB; Dijkstra, PU

    2004-01-01

    Purpose : To analyse how decisions to dichotomise the frequency and impediment of phantom pain into absent and present influence the outcome of studies by performing a sensitivity analysis on an existing database. Method : Five hundred and thirty-six subjects were recruited from the database of an o

  5. Psychophysical correlates of phantom limb experience.

    OpenAIRE

    Katz, J

    1992-01-01

    Phantom limb phenomena were correlated with psychophysiological measures of peripheral sympathetic nervous system activity measured at the amputation stump and contralateral limb. Amputees were assigned to one of three groups depending on whether they reported phantom limb pain, non-painful phantom limb sensations, or no phantom limb at all. Skin conductance and skin temperature were recorded continuously during two 30 minute sessions while subjects continuously monitored and rated the intens...

  6. A comparative study on patient specific absolute dosimetry using slab phantom, acrylic body phantom and goat head phantom

    Directory of Open Access Journals (Sweden)

    Om Prakash Gurjar

    2015-01-01

    Full Text Available Purpose: To compare the results of patient specific absolute dosimetry using slab phantom, acrylic body phantom and goat head phantom. Methods: Fifteen intensity modulated radiotherapy (IMRT plans already planned on treatment planning system (TPS for head-and-neck cancer patients were exported on all three kinds of phantoms viz. slab phantom, acrylic body phantom and goat head phantom, and dose was calculated using anisotropic analytic algorithm (AAA. All the gantry angles were set to zero in case of slab phantom while set to as it is in actual plan in case of other two phantoms. All the plans were delivered by linear accelerator (LA and dose for each plan was measured by 0.13 cc ion chamber. The percentage (% variations between planned and measured doses were calculated and analyzed. Results: The mean % variations between planned and measured doses of all IMRT quality assurance (QA plans were as 0.65 (Standard deviation (SD: 0.38 with confidence limit (CL 1.39, 1.16 (SD: 0.61 with CL 2.36 and 2.40 (SD: 0.86 with CL 4.09 for slab phantom, acrylic head phantom and goat head phantom respectively. Conclusion: Higher dose variations found in case of real tissue phantom compare to results in case of slab and acrylic body phantoms. The algorithm AAA does not calculate doses in heterogeneous medium as accurate as it calculates in homogeneous medium. Therefore the patient specific absolute dosimetry should be done using heterogeneous phantom mimicking density wise as well as design wise to the actual human body.  

  7. Phantom Dark Energy and its Cosmological Consequences

    CERN Document Server

    Dabrowski, Mariusz P

    2016-01-01

    I discuss the dark energy characterized by the violation of the null energy condition ($\\varrho + p \\geq 0$), dubbed phantom. Amazingly, it is admitted by the current astronomical data from supernovae. We discuss both classical and quantum cosmological models with phantom as a source of matter and present the phenomenon called phantom duality.

  8. Phantom limb pain and related disorders.

    Science.gov (United States)

    Weinstein, S M

    1998-11-01

    Postamputation phenomena, including painful and nonpainful phantom sensations occur following loss of limbs and other body parts. Peripheral and central nervous system mechanisms play a role in persistent phantom pain. Understanding the pathophysiology of this syndrome has improved in recent years. Comprehensive evaluation and a multimodality treatment approach comprise the current standard of care of the patient with phantom pain.

  9. Time evolving multi-city dependencies and robustness tradeoffs for risk-based portfolios of conservation, transfers, and cooperative water supply infrastructure development pathways

    Science.gov (United States)

    Trindade, B. C.; Reed, P. M.; Zeff, H. B.; Characklis, G. W.

    2016-12-01

    Water scarcity in historically water-rich regions such as the southeastern United States is becoming a more prevalent concern. It has been shown that cooperative short-term planning that relies on conservation and transfers of existing supplies amongst communities can be used by water utilities to mitigate the effects of water scarcity in the near future. However, in the longer term, infrastructure expansion is likely to be necessary to address imbalances between growing water demands and the available supply capacity. This study seeks to better diagnose and avoid candidate modes for system failure. Although it is becoming more common for water utilities to evaluate the robustness of their water supply, defined as the insensitivity of their systems to errors in deeply uncertain projections or assumptions, defining robustness is particularly challenging in multi-stakeholder regional contexts for decisions that encompass short management actions and long-term infrastructure planning. Planning and management decisions are highly interdependent and strongly shape how a region's infrastructure itself evolves. This research advances the concept of system robustness by making it evolve over time rather than static, so that it is applicable to an adaptive system and therefore more suited for use for combined short and long-term planning efforts. The test case for this research is the Research Triangle area of North Carolina, where the cities of Raleigh, Durham, Cary and Chapel Hill are experiencing rapid population growth and increasing concerns over drought. This study is facilitating their engagement in cooperative and robust regional water portfolio planning. The insights from this work have general merit for regions where adjacent municipalities can benefit from improving cooperative infrastructure investments and more efficient resource management strategies.

  10. Phantom pain and phantom sensations in upper limb amputees: an epidemiological study

    OpenAIRE

    Kooijman, CM; Dijkstra, PU; Geertzen, JHB; Elzinga, A; Van Der Schans, CP

    2000-01-01

    Phantom pain in subjects with an amputated limb is a well-known problem. However, estimates of the prevalence of phantom pain differ considerably in the literature. Various factors associated with phantom pain have been described including pain before the amputation, gender, dominance, and time elapsed since the amputation. The purposes of this study were to determine prevalence and factors associated with phantom pain and phantom sensations in upper limb amputees in The Netherlands. Addition...

  11. Phantom limb syndrome: a review.

    Science.gov (United States)

    Chahine, Lama; Kanazi, Ghassan

    2007-06-01

    Phantom limb syndrome is a condition in which patients experience sensations, whether painful or otherwise, in a limb that does not exist. It has been reported to occur in 80-100% of amputees, and typically has a chronic course, often resistant to treatment. Risk factors include the presence of preoperative pain, traumatic amputation, and the type of anesthetic procedure used during amputation. Several pathophysiologic theories have been proposed, including spinal mechanisms, central sensitization, and somatosensory cortical rearrangements, and while recent studies have shed light on some interesting and significant data, a lot remains to be understood. Treatments include pharmacologic, mechanical, and behavioral modalities, but substantial efficacy in well-designed, randomized controlled trials has yet to be demonstrated. Phantom limb syndrome continues to be a difficult condition to both understand and treat.

  12. 1998 research cooperation project. Research cooperation on environment-compatible type water resource effective-utilization system; 1998 nendo kankyo taiogata mizushigen yuko riyo system ni kansuru kenkyu kyoryoku

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    For the purpose of securing water stably and preventing water pollution in the Philippines, R and D were carried out on a wastewater treatment and water reclamation and reuse system which is easy to operate and maintain and low in cost through the research cooperation between the Philippine Industrial Technology Development Institute and Japan. According to the survey result of statistical data concerning water pollution load structure by industrial wastewater classified by the industry in the Philippines, enumerated are the food manufacturing industry, paper pulp manufacturing industry, and the textile dyeing industry as those greatly affecting water pollution in BOD exhaust and wastewater, etc. Consequently, with Ram Food Product Co. of vegetable processing and Solid Mill Co., of textile dyeing as plants to be studied, a wastewater treatment test was performed in a laboratory scale. From the result of the test, the pilot plant was basically designed to have 'anaerobic + aerobic treatment + tertiary treatment' for the treatment process, with an one-tank type UASB method used as the anaerobic treatment, with a sand filtration + activated charcoal treatment as the tertiary treatment, and with the cost effectiveness for water reuse set to be examined. (NEDO)

  13. Complex Lagrangians and phantom cosmology

    CERN Document Server

    Andrianov, A A; Kamenshchik, A Yu

    2006-01-01

    Motivated by the generalization of quantum theory for the case of non-Hermitian Hamiltonians with PT symmetry, we show how a classical cosmological model describes a smooth transition from ordinary dark energy to the phantom one. The model is based on a classical complex Lagrangian of a scalar field. Specific symmetry properties analogous to PT in non-Hermitian quantum mechanics lead to purely real equation of motion.

  14. Estimation of computed tomography dose in various phantom shapes and compositions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Lae [Dept. of Radiological Science, Yonsei University, Seoul (Korea, Republic of)

    2017-03-15

    The purpose of this study was to investigate CTDI (computed tomography dose index at center) for various phantom shapes, sizes, and compositions by using GATE (geant4 application for tomographic emission) simulations. GATE simulations were performed for various phantom shapes (cylinder, elliptical, and hexagonal prism PMMA phantoms) and phantom compositions (water, PMMA, polyethylene, polyoxymethylene) with various diameters (1-50 cm) at various kVp and mAs levels. The CTDI100center values of cylinder, elliptical, and hexagonal prism phantom at 120 kVp, 200 mAs resulted in 11.1, 13.4, and 12.2 mGy, respectively. The volume is the same, but CTDI{sub 100center} values are different depending on the type of phantom. The water, PMMA, and polyoxymethylene phantom CTDI{sub 100center} values were relatively low as the material density increased. However, in the case of Polyethylene, the CTDI{sub 100center} value was higher than that of PMMA at diameters exceeding 15 cm (CTDI{sub 100center} : 35.0 mGy). And a diameter greater than 30 cm (CTDI{sub 100center} : 17.7 mGy) showed more CTDI{sub 100center} than Water. We have used limited phantoms to evaluate CT doses. In this study, CTDI{sub 100center} values were estimated and simulated by GATE simulation according to the material and shape of the phantom. CT dosimetry can be estimated more accurately by using various materials and phantom shapes close to human body.

  15. Conflictual cooperation

    DEFF Research Database (Denmark)

    Axel, Erik

    2011-01-01

    , cooperation appeared as the continuous reworking of contradictions in the local arrangement of societal con- ditions. Subjects were distributed and distributed themselves according to social privileges, resources, and dilemmas in cooperation. Here, the subjects’ activities and understandings took form from...

  16. Cooperative Learning

    Institute of Scientific and Technical Information of China (English)

    桑莹莹

    2015-01-01

    This paper is about the cooperative learning as a teaching method in a second language learning class. It mainly talks about the background, foundation, features, definitions, components, goals, advantages and disadvantages of cooperative learning. And as the encounter of the disadvantages in cooperative learning, this paper also proposes some strategies.

  17. Relative stopping power measurements to aid in the design of anthropomorphic phantoms for proton radiotherapy.

    Science.gov (United States)

    Grant, Ryan L; Summers, Paige A; Neihart, James L; Blatnica, Anthony P; Sahoo, Narayan; Gillin, Michael T; Followill, David S; Ibbott, Geoffrey S

    2014-03-06

    The delivery of accurate proton dose for clinical trials requires that the appropriate conversion function from Hounsfield unit (HU) to relative linear stopping power (RLSP) be used in proton treatment planning systems (TPS). One way of verifying that the TPS is calculating the correct dose is an end-to-end test using an anthropomorphic phantom containing tissue equivalent materials and dosimeters. Many of the phantoms in use for such end-to-end tests were originally designed using tissue-equivalent materials that had physical characteristics to match patient tissues when irradiated with megavoltage photon beams. The aim of this study was to measure the RLSP of materials used in the phantoms, as well as alternative materials to enable modifying phantoms for use at proton therapy centers. Samples of materials used and projected for use in the phantoms were measured and compared to the HU assigned by the treatment planning system. A percent difference in RLSP of 5% was used as the cutoff for materials deemed acceptable for use in proton therapy (i.e., proton equivalent). Until proper tissue-substitute materials are identified and incorporated, institutions that conduct end-to-end tests with the phantoms are instructed to override the TPS with the measured stopping powers we provide. To date, the RLSPs of 18 materials have been measured using a water phantom and/or multilayer ion chamber (MLIC). Nine materials were identified as acceptable for use in anthropomorphic phantoms. Some of the failing tissue substitute materials are still used in the current phantoms. Further investigation for additional appropriate tissue substitute materials in proton beams is ongoing. Until all anthropomorphic phantoms are constructed of appropriate materials, a unique HU-RLSP phantom has been developed to be used during site visits to verify the proton facility's treatment planning HU-RLSP calibration curve.

  18. NOTE: Computational study of the required dimensions for standard sized phantoms in boron neutron capture therapy dosimetry

    Science.gov (United States)

    Koivunoro, H.; Auterinen, I.; Kosunen, A.; Kotiluoto, P.; Seppälä, T.; Savolainen, S.

    2003-11-01

    The minimum size of a water phantom used for calibration of an epithermal neutron beam of the boron neutron capture therapy (BNCT) facility at the VTT FiR 1 research reactor is studied by Monte Carlo simulations. The criteria for the size of the phantom were established relative to the neutron and photon radiation fields present at the thermal neutron fluence maximum in the central beam axis (considered as the reference point). At the reference point, for the most commonly used beam aperture size at FiR 1 (14 cm diameter), less than 1% disturbance of the neutron and gamma radiation fields in a phantom were achieved with a minimum a 30 cm × 30 cm cross section of the phantom. For the largest 20 cm diameter beam aperture size, a minimum 40 cm × 40 cm cross-section of the phantom and depth of 20 cm was required to achieve undisturbed radiation field. This size can be considered as the minimum requirement for a reference phantom for dosimetry at FiR 1. The secondary objective was to determine the phantom dimensions for full characterization of the FiR 1 beam in a rectangular water phantom. In the water scanning phantom, isodoses down to the 5% level are measured for the verifications of the beam model in the dosimetric and treatment planning calculations. The dose distribution results without effects caused by the limited phantom size were achieved for the maximum aperture diameter (20 cm) with a 56 cm × 56 cm × 28 cm rectangular phantom. A similar approach to study the required minimum dimensions of the reference and water scanning phantoms can be used for epithermal neutron beams at the other BNCT facilities.

  19. Phantom limb after stroke: an underreported phenomenon.

    Science.gov (United States)

    Antoniello, Daniel; Kluger, Benzi M; Sahlein, Daniel H; Heilman, Kenneth M

    2010-10-01

    The presence of a phantom limb (PL) resulting from a cerebral lesion has been reported to be a rare event. No prior study, however, has systematically investigated the prevalence of this syndrome in a group of post-stroke individuals. Fifty post-stroke individuals were examined with structured interview/questionnaire to establish the presence and perceptual characteristics of PLs. We document the presence of phantom experiences in over half of these individuals (n=27). We provide details of these phantom experiences and further characterize these symptoms in terms of temporal qualities, posture, kinesthesia, and associated features. Twenty-two participants reported postural phantoms, which were perceived as illusions of limb position that commonly manifested while lying in bed at night - a time when visual input is removed from multi-sensory integration. Fourteen participants reported kinesthetic phantoms, with illusory movements ranging from simple single joint sensations to complex goal-directed phantom movements. A striking syndrome of near total volitional control of phantom movements was reported in four participants who had immobile plegic hands. Reduplicative phantom percepts were reported by only one participant. Similarly, phantom pain was present in only one individual - the sole participant with a pre-stroke limb amputation. The results suggest that stroke results in phantom experiences more commonly than previously described in the literature. We speculate that subtotal deafferance or defective motor efference after stroke may manifest intermittently as a PL.

  20. Psychophysical correlates of phantom limb experience.

    Science.gov (United States)

    Katz, J

    1992-09-01

    Phantom limb phenomena were correlated with psychophysiological measures of peripheral sympathetic nervous system activity measured at the amputation stump and contralateral limb. Amputees were assigned to one of three groups depending on whether they reported phantom limb pain, non-painful phantom limb sensations, or no phantom limb at all. Skin conductance and skin temperature were recorded continuously during two 30 minute sessions while subjects continuously monitored and rated the intensity of any phantom limb sensation or pain they experienced. The results from both sessions showed that mean skin temperature was significantly lower at the stump than the contralateral limb in the groups with phantom limb pain and non-painful phantom limb sensations, but not among subjects with no phantom limb at all. In addition, stump skin conductance responses correlated significantly with the intensity of non-painful phantom limb paresthesiae but not other qualities of sensation or pain. Between-limb measures of pressure sensitivity were not significantly different in any group. The results suggest that the presence of a phantom limb, whether painful or painless, is related to the sympathetic-efferent outflow of cutaneous vasoconstrictor fibres in the stump and stump neuromas. The hypothesis of a sympathetic-efferent somatic-afferent mechanism involving both sudomotor and vasoconstrictor fibres is proposed to explain the relationship between stump skin conductance responses and non-painful phantom limb paresthesiae. It is suggested that increases in the intensity of phantom limb paresthesiae follow bursts of sympathetic activity due to neurotransmitter release onto apposing sprouts of large diameter primary afferents located in stump neuromas, and decreases correspond to periods of relative sympathetic inactivity. The results of the study agree with recent suggestions that phantom limb pain is not a unitary syndrome, but a symptom class with each class subserved by

  1. MO-F-CAMPUS-T-01: IROC Houston QA Center’s Anthropomorphic Proton Phantom Program

    Energy Technology Data Exchange (ETDEWEB)

    Lujano, C; Hernandez, N; Keith, T; Nguyen, T; Taylor, P; Molineu, A; Followill, D [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: To describe the proton phantoms that IROC Houston uses to approve and credential proton institutions to participate in NCI-sponsored clinical trials. Methods: Photon phantoms cannot necessarily be used for proton measurements because protons react differently than photons in some plastics. As such plastics that are tissue equivalent for protons were identified. Another required alteration is to ensure that the film dosimeters are housed in the phantom with no air gap to avoid proton streaming. Proton-equivalent plastics/materials used include RMI Solid Water, Techron HPV, blue water, RANDO soft tissue material, balsa wood, compressed cork and polyethylene. Institutions wishing to be approved or credentialed request a phantom and are prioritized for delivery. At the institution, the phantom is imaged, a treatment plan is developed, positioned on the treatment couch and the treatment is delivered. The phantom is returned and the measured dose distributions are compared to the institution’s electronically submitted treatment plan dosimetry data. Results: IROC Houston has developed an extensive proton phantom approval/credentialing program consisting of five different phantoms designs: head, prostate, lung, liver and spine. The phantoms are made with proton equivalent plastics that have HU and relative stopping powers similar (within 5%) of human tissues. They also have imageable targets, avoidance structures, and heterogeneities. TLD and radiochromic film are contained in the target structures. There have been 13 head, 33 prostate, 18 lung, 2 liver and 16 spine irradiations with either passive scatter, or scanned proton beams. The pass rates have been: 100%, 69.7%, 72.2%, 50%, and 81.3%, respectively. Conclusion: IROC Houston has responded to the recent surge in proton facilities by developing a family of anthropomorphic phantoms that are able to be used for remote audits of proton beams. Work supported by PHS grant CA10953 and CA081647.

  2. Dosimetric comparison of tools for intensity modulated radiation therapy with gamma analysis: a phantom study

    Directory of Open Access Journals (Sweden)

    Akbas Ugur

    2015-01-01

    Full Text Available Dosimetry of the Intensity Modulated Radiation Therapy (IMRT is very important because of the complex dose distributions. Diode arrays are the most common and practical measurement tools for clinical usage for IMRT. Phantom selection is critical for QA process. IMRT treatment plans are recalculated for the phantom irradiation in QA. Phantoms are made in different geometrical shapes to measure the doses of different types of irradiation techniques. Comparison of measured and calculated dose distributions for IMRT can be made by using gamma analysis. In this study, 10 head-and-neck IMRT QA plans were created with Varian Eclipse 8.9 treatment planning system. Water equivalent RW3-slab phantoms, Octavius-2 phantom and PTW Seven29 2D-array were used for QA measurements. Gantry, collimator and couch positions set to 00 and QA plans were delivered to RW3 and Octavius phantoms. Then the positions set to original angles and QA plans irradiated again. Measured and calculated fluence maps were evaluated with gamma analysis for different DD and DTA criteria. The effect of different set-up conditions for RW3 and Octavius phantoms in QA plan delivery evaluated by gamma analysis. Results of gamma analysis show that using RW3-slab phantoms with setting parameters to 00 is more appropriate for IMRT QA.

  3. Dosimetric comparison of tools for intensity modulated radiation therapy with gamma analysis: a phantom study

    Science.gov (United States)

    Akbas, Ugur; Okutan, Murat; Demir, Bayram; Koksal, Canan

    2015-07-01

    Dosimetry of the Intensity Modulated Radiation Therapy (IMRT) is very important because of the complex dose distributions. Diode arrays are the most common and practical measurement tools for clinical usage for IMRT. Phantom selection is critical for QA process. IMRT treatment plans are recalculated for the phantom irradiation in QA. Phantoms are made in different geometrical shapes to measure the doses of different types of irradiation techniques. Comparison of measured and calculated dose distributions for IMRT can be made by using gamma analysis. In this study, 10 head-and-neck IMRT QA plans were created with Varian Eclipse 8.9 treatment planning system. Water equivalent RW3-slab phantoms, Octavius-2 phantom and PTW Seven29 2D-array were used for QA measurements. Gantry, collimator and couch positions set to 00 and QA plans were delivered to RW3 and Octavius phantoms. Then the positions set to original angles and QA plans irradiated again. Measured and calculated fluence maps were evaluated with gamma analysis for different DD and DTA criteria. The effect of different set-up conditions for RW3 and Octavius phantoms in QA plan delivery evaluated by gamma analysis. Results of gamma analysis show that using RW3-slab phantoms with setting parameters to 00 is more appropriate for IMRT QA.

  4. Assessing the value of cooperation and information exchange in large water resources systems by multi-agent optimization: the Zambezi river case

    Science.gov (United States)

    Giuliani, M.; Castelletti, A.

    2012-04-01

    Many large-scale water resources systems are characterized by the presence of several and conflicting interests and are often managed by many independent decision-makers, belonging to different institutions or countries, who take into account only their own objectives causing downstream externalities. In this work we explore the use of multi-agent systems theory to conduct an optimization-based analysis of different levels of cooperation and information exchange in the large water reservoir system of the Zambezi River. The four largest reservoirs in the basin (Ithezhithezhi, Kafue-Gorge, Kariba and Cahora Bassa) are mainly operated for maximizing the economic revenue from hydropower energy production with considerably negative effects on the aquatic ecosystem in the Zambezi delta. We comparatively analyse the ideal situation in which a central decision-maker optimizes a global optimum and the more realistic case where all the decision-makers act independently and non-cooperatively. We then investigate how increasing levels of information exchange can help in mitigating the conflict generated by a non-cooperative setting.

  5. Research cooperation project in fiscal 1998. General report on research cooperation related to mine waste water treatment technology by utilizing biotechnology; 1998 nendo kenkyu kyoryoku jigyo. Bio riyo ni yoru kohaisui shori gijutsu ni kansuru kenkyu kyoryoku sokatsu hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    This paper describes cooperative development of bio-treatment technology for mine waste water generated by operating mines in China. Certain types of bacteria have capability to oxidize ferrous iron in the waste water into ferric iron ions. The bacteria cause ferric iron oxides in low pH regions to get deposited, and can remove them from sedimentation by using cheap calcium carbonate as a neutralizer. Volumetric reduction in waste sediments may also be achieved during removing heavy metals in a pretreatment process. Great advance may be expected in taking actions to prevent water quality contamination. This paper summarizes activities taken in fiscal 1998. Eight site surveys in total were carried out using 47 persons in total. Major activities included operation study guidance of a pilot plant, and surveys for measures on heavy metal generation sources in Wushan Mine. In addition, site surveys were performed at Dexing Mine and Yinshan Zinc Mine. Subsequently from fiscal 1997, a bench scale testing equipment used in Japan and consumables were transported to China. The operation study data on the pilot plant were put into order and analyzed. Concept design was also made on a waste water treatment facility for Wushan Mine. (NEDO)

  6. Exact solution of phantom dark energy model

    Institute of Scientific and Technical Information of China (English)

    Wang Wen-Fu; Shui Zheng-Wei; Tang Bin

    2010-01-01

    We investigate the phantom dark energy model derived from the scalar field with a negative kinetic term. By assuming a particular relation between the time derivative of the phantom field and the Hubble function, an exact solution of the model is constructed. Absence of the 'big rip' singularity is shown explicitly. We then derive special features of phantom dark energy model and show that its predictions are consistent with all astrophysical observations.

  7. Phantom dosimetry at 15 MV conformal radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa; Campos, Tarcisio P.R., E-mail: larissathompson@hotmail.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Dias, Humberto G., E-mail: fisicamedica.hl@mariopenna.org.br [Luxemburgo Hospital, Mario Penna Institute, Belo Horizonte, MG (Brazil)

    2015-07-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  8. Phantom dosimetry at 15 MV conformal radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa; Campos, Tarcisio P.R., E-mail: larissathompson@hotmail.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Minas Gerais, MG (Brazil). Dept. de Engenharia Nuclear; Dias, Humberto G., E-mail: fisicamedica.hl@mariopenna.org.br [Instituto Mario Penna, Minas Gerais, MG (Brazil). Hospital Luxemburgo

    2013-07-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  9. Galileons, phantom and the Fate of Universe

    CERN Document Server

    Shahalam, M; Myrzakulov, R

    2016-01-01

    In this paper we study cosmological dynamics of phantom as well as non-phantom fields with linear potential in presence of Galileon correction $(\\partial_\\mu\\phi \\partial^\\mu\\phi) \\Box \\phi$. We show that the Big Crunch singularity is delayed compared to the standard case; the delay crucially depends upon the strength of Galileon correction. As for the phantom Galileon, $\\rho_{\\phi}$ is shown to grow more slowly compared to the standard phantom delaying the approach to singularity. In case, $V\\sim \\phi^n, n>4$, Big Rip is also delayed, similar phenomenon is shown to take place for potentials steeper than the exponential.

  10. Do Phantom Cuntz-Krieger Algebras Exist?

    DEFF Research Database (Denmark)

    Arklint, Sara E.

    2013-01-01

    If phantom Cuntz-Krieger algebras do not exist, then purely infinite Cuntz-Krieger algebras can be characterized by outer properties. In this survey paper, a summary of the known results on non-existence of phantom Cuntz-Krieger algebras is given......If phantom Cuntz-Krieger algebras do not exist, then purely infinite Cuntz-Krieger algebras can be characterized by outer properties. In this survey paper, a summary of the known results on non-existence of phantom Cuntz-Krieger algebras is given...

  11. Do you believe in phantoms?

    CERN Multimedia

    Rosaria Marraffino

    2015-01-01

    “Phantoms” are tools that simulate a therapy’s response by mimicking the conditions of the human body. They are required in hadron therapy in order to optimise and verify the therapy before performing it on the patient. The better the phantom, the more accurate the treatment plan and the more effective the therapy. In the framework of the EU-funded project ENTERVISION*, a team of CERN researchers has designed an innovative piece of equipment able to evaluate radiobiology-related parameters in a very accurate way.   The ENTERVISION phantom being tested at HIT. A key challenge in hadron therapy – i.e. the medical use of hadrons to treat cancer – is to evaluate the biological effect of the delivered radiation. This can be achieved by using accurate dosimetry techniques to study the biological response in terms of the dose deposited and other physical parameters of the beam, such as the Linear Energy Transfer (LET). The job of the “phan...

  12. Transorbital therapy delivery: phantom testing

    Science.gov (United States)

    Ingram, Martha-Conley; Atuegwu, Nkiruka; Mawn, Louise; Galloway, Robert L.

    2011-03-01

    We have developed a combined image-guided and minimally invasive system for the delivery of therapy to the back of the eye. It is composed of a short 4.5 mm diameter endoscope with a magnetic tracker embedded in the tip. In previous work we have defined an optimized fiducial placement for accurate guidance to the back of the eye and are now moving to system testing. The fundamental difficulty in testing performance is establishing a target in a manner which closely mimics the physiological task. We have to have a penetrable material which obscures line of sight, similar to the orbital fat. In addition we need to have some independent measure of knowing when a target has been reached to compare to the ideal performance. Lastly, the target cannot be rigidly attached to the skull phantom since the optic nerve lies buried in the orbital fat. We have developed a skull phantom with white cloth stellate balls supporting a correctly sized globe. Placed in the white balls are red, blue, orange and yellow balls. One of the colored balls has been soaked in barium to make it bright on CT. The user guides the tracked endoscope to the target as defined by the images and tells us its color. We record task accuracy and time to target. We have tested this with 28 residents, fellows and attending physicians. Each physician performs the task twice guided and twice unguided. Results will be presented.

  13. Development of a HIFU Phantom

    Science.gov (United States)

    King, Randy L.; Herman, Bruce A.; Maruvada, Subha; Wear, Keith A.; Harris, Gerald R.

    2007-05-01

    The field of high intensity focused ultrasound (HIFU) is developing rapidly. For basic research, quality control, and regulatory assessment a reusable phantom that has both thermal and acoustic properties close to that of soft tissue is critical. A hydrogel-based tissue mimicking material (TMM) has been developed that shows promise for such a phantom. The acoustic attenuation, speed of sound, B/A, thermal diffusivity and conductivity, as well as the cavitation threshold, were measured and found to mimic published values for soft tissue. The attenuation of 0.53f1.04 from 1 MHz to 8 MHz, as well as the sound speed of 1565 m/s and the tissue-like image quality, indicate the usefulness of the TMM for ultrasound imaging applications. These properties along with the thermal conductivity of 0.58 W/m- °C, diffusivity of 0.15 (mm2)/s, and the ability to withstand temperatures above 95 °C make this material appropriate for HIFU applications. The TMM also allows for the embedding of thermocouples and the formation of wall-less vessels that do not deteriorate as a result of continuous flow of blood mimicking fluids through the material. Tissue characteristics are strongly dependent on the fabrication technique, and care must be taken to achieve reproducible results. Note: This research was supported by the Defense Advanced Research Projects Agency (DARPA).

  14. The phantom limb in dreams.

    Science.gov (United States)

    Brugger, Peter

    2008-12-01

    Mulder and colleagues [Mulder, T., Hochstenbach, J., Dijkstra, P. U., Geertzen, J. H. B. (2008). Born to adapt, but not in your dreams. Consciousness and Cognition, 17, 1266-1271.] report that a majority of amputees continue to experience a normally-limbed body during their night dreams. They interprete this observation as a failure of the body schema to adapt to the new body shape. The present note does not question this interpretation, but points to the already existing literature on the phenomenology of the phantom limb in dreams. A summary of published investigations is complemented by a note on phantom phenomena in the dreams of paraplegic patients and persons born without a limb. Integration of the available data allows the recommendation for prospective studies to consider dream content in more detail. For instance, "adaptation" to the loss of a limb can also manifest itself by seeing oneself surrounded by amputees. Such projective types of anosognosia ("transitivism") in nocturnal dreams should also be experimentally induced in normally-limbed individuals, and some relevant techniques are mentioned.

  15. Phantom pain and phantom sensations in upper limb amputees : an epidemiological study

    NARCIS (Netherlands)

    Kooijman, CM; Dijkstra, PU; Geertzen, JHB; Elzinga, A; van der Schans, CP

    2000-01-01

    Phantom pain in subjects with an amputated limb is a well-known problem. However, estimates of the prevalence of phantom pain differ considerably in the literature. Various factors associated with phantom pain have been described including pain before the amputation, gender, dominance, and time elap

  16. Teflon cylindrical phantom for delivery quality assurance of stereotactic body radiotherapy (SBRT).

    Science.gov (United States)

    Lack, Danielle W; Kakakhel, Ali; Starin, Ross; Snyder, Michael

    2014-01-06

    At our institution the standard delivery quality assurance (DQA) procedure for tomotherapy plans is accomplished with a water equivalent phantom, EDR2 film, and ion chamber point-dose measurements. Most plans deliver at most 5 Gy to the dose plane; however, recently a stereotactic body radiotherapy (SBRT) protocol has produced plans delivering upwards of 12 Gy to the film plane. EDR2 film saturates at a dose of ~ 7 Gy, requiring a modification of our DQA procedure for SBRT plans. To reduce the dose to the film plane and accommodate a possible move to SBRT using Varian RapidArc, a Teflon phantom has been constructed and tested. Our Teflon phantom is cylindrical in shape and of a similar design to the standard phantom. The phantom was MVCT scanned on the TomoTherapy system with images imported into the TomoTherapy and Varian Eclipse planning systems. Phantom images were smoothed to reduce artifacts for treatment planning purposes. Verification SBRT plans were delivered with film and point-dose benchmarked against the standard procedure. Verification tolerance criteria were 3% dose difference for chamber measurements and a gamma pass rate > 90% for film (criteria: 3 mm DTA, 3% dose difference, 10% threshold). The phantom sufficiently reduced dose to the film plane for DQA of SBRT plans. Both planning systems calculated accurate point doses in phantom, with the largest differences being 2.4% and 4.4% for TomoTherapy and Rapid Arc plans. Measured dose distributions correlated well with planning system calculations (γ 95%). These results were comparable to the standard phantom. The Teflon phantom appears to be a potential option for SBRT DQA. Preliminary data show that the planning systems are capable of calculating point doses in the Teflon, and the dose to the film plane is reduced sufficiently to allow for a direct measured DQA without the need for dose rescaling.

  17. Towards co-operative governance in the development and implementation of cross-sectoral policy: water policy as an example

    CSIR Research Space (South Africa)

    MacKay, HM

    2004-01-01

    Full Text Available to be established on the ground, and not just considered as some form of laudable principle. One of the most important steps in moving towards operational co-operative governance is the identification and agreement, by all the relevant and affected sectors...

  18. Unifying phantom inflation with late-time acceleration: scalar phantom-non-phantom transition model and generalized holographic dark energy

    CERN Document Server

    Nojiri, S; Nojiri, Shin'ichi; Odintsov, Sergei D.

    2005-01-01

    The unifying approach to early-time and late-time universe based on phantom cosmology is proposed. We consider gravity-scalar system which contains usual potential and scalar coupling function in front of kinetic term. As a result, the possibility of phantom-non-phantom transition appears in such a way that universe could have effectively phantom equation of state at early time as well as at late time. In fact, the oscillating universe may have several phantom and non-phantom phases. As a second model we suggest generalized holographic dark energy where infrared cutoff is identified with combination of FRW parameters: Hubble constant, particle and future horizons, cosmological constant and universe life-time (if finite). Depending on the specific choice of the model the number of interesting effects occur: the possibility to solve the coincidence problem, crossing of phantom divide and unification of early-time inflationary and late-time accelerating phantom universe. The bound for holographic entropy which d...

  19. Phantom pain and risk factors : A multivariate analysis

    NARCIS (Netherlands)

    Dijkstra, PU; Geertzen, JHB; Stewart, R; van der Schans, CP

    2002-01-01

    Phantom pain has been given considerable attention in literature. Phantom Pain reduces quality of life, and patients suffering from phantom pain make heavy use of the medical system. Many risk factors have been identified for phantom Pain in univariate analyses, including phantom sensations, stump P

  20. Phantom pain and risk factors : A multivariate analysis

    NARCIS (Netherlands)

    Dijkstra, PU; Geertzen, JHB; Stewart, R; van der Schans, CP

    2002-01-01

    Phantom pain has been given considerable attention in literature. Phantom Pain reduces quality of life, and patients suffering from phantom pain make heavy use of the medical system. Many risk factors have been identified for phantom Pain in univariate analyses, including phantom sensations, stump P

  1. Skin Dosimetry in Breast Teletherapy on a Phantom Anthropomorphic and Anthropometric Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Batista Nogueira, Luciana [Anatomy and Imaging Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Lemos Silva, Hugo Leonardo [Santa Casa Hospital, Belo Horizonte (Brazil); Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio [Nuclear Engineering Department, Federal University of Minas Gerais, Belo Horizonte (Brazil)

    2015-07-01

    This paper addresses the breast teletherapy dosimetry. The goal is to evaluate and compare absorbed doses in equivalent skin tissue, TE-skin, of an anthropomorphic and anthropometric breast phantom submitted to breast radiotherapy. The methodology involved the reproduction of a set of tomographic images of the phantom; the elaboration of conformational radiotherapy planning in the SOMAVISION and CadPlan (TPS) software; and the synthetic breast irradiation by parallel opposed fields in 3D conformal teletherapy at 6 MV linear accelerator Clinac-2100 C from VARIAN with prescribed dose (PD) of 180 cGy to the target volume (PTV), referent to the glandular tissue. Radiochromic films EBT2 were selected as dosimeters. Two independent calibration processes of films with solid water Gammex 457 plates and water filled box were produced. Curves of optical density (OD) versus absorbed dose were produced. Dosimeters were positioned in the external region of the breast phantom in contact with TE-skin, area of 4.0 cm{sup 2} each. The irradiation process was prepared in duplicate to check the reproducibility of the technique. The radiochromic films were scanned and their response in RGB (Red, Green, Blue) analyzed by the ImageJ software. The optical density was obtained and converted to dose based on the calibration curves. Thus, the spatial dose distribution in the skin was reproduced. The absorbed doses measured on the radiochromic films in TE-skin showed values between upper and lower quadrants at 9 o'clock in the range of 54% of PD, between the upper and lower quadrants 3 o'clock in the range of 72% and 6 o'clock at the lower quadrant in the range of 68 % of PD. The values are ±64% (p <0.05) according to the TPS. It is concluded that the depth dose measured in solid water plates or water box reproduce equivalent dose values for both calibration processes of the radiochromic films. It was observed that the skin received doses ranging from 50% to 78% of the

  2. The collapsed cone algorithm for (192)Ir dosimetry using phantom-size adaptive multiple-scatter point kernels.

    Science.gov (United States)

    Tedgren, Åsa Carlsson; Plamondon, Mathieu; Beaulieu, Luc

    2015-07-07

    The aim of this work was to investigate how dose distributions calculated with the collapsed cone (CC) algorithm depend on the size of the water phantom used in deriving the point kernel for multiple scatter. A research version of the CC algorithm equipped with a set of selectable point kernels for multiple-scatter dose that had initially been derived in water phantoms of various dimensions was used. The new point kernels were generated using EGSnrc in spherical water phantoms of radii 5 cm, 7.5 cm, 10 cm, 15 cm, 20 cm, 30 cm and 50 cm. Dose distributions derived with CC in water phantoms of different dimensions and in a CT-based clinical breast geometry were compared to Monte Carlo (MC) simulations using the Geant4-based brachytherapy specific MC code Algebra. Agreement with MC within 1% was obtained when the dimensions of the phantom used to derive the multiple-scatter kernel were similar to those of the calculation phantom. Doses are overestimated at phantom edges when kernels are derived in larger phantoms and underestimated when derived in smaller phantoms (by around 2% to 7% depending on distance from source and phantom dimensions). CC agrees well with MC in the high dose region of a breast implant and is superior to TG43 in determining skin doses for all multiple-scatter point kernel sizes. Increased agreement between CC and MC is achieved when the point kernel is comparable to breast dimensions. The investigated approximation in multiple scatter dose depends on the choice of point kernel in relation to phantom size and yields a significant fraction of the total dose only at distances of several centimeters from a source/implant which correspond to volumes of low doses. The current implementation of the CC algorithm utilizes a point kernel derived in a comparatively large (radius 20 cm) water phantom. A fixed point kernel leads to predictable behaviour of the algorithm with the worst case being a source/implant located well within a patient/phantom

  3. The collapsed cone algorithm for 192Ir dosimetry using phantom-size adaptive multiple-scatter point kernels

    Science.gov (United States)

    Carlsson Tedgren, Åsa; Plamondon, Mathieu; Beaulieu, Luc

    2015-07-01

    The aim of this work was to investigate how dose distributions calculated with the collapsed cone (CC) algorithm depend on the size of the water phantom used in deriving the point kernel for multiple scatter. A research version of the CC algorithm equipped with a set of selectable point kernels for multiple-scatter dose that had initially been derived in water phantoms of various dimensions was used. The new point kernels were generated using EGSnrc in spherical water phantoms of radii 5 cm, 7.5 cm, 10 cm, 15 cm, 20 cm, 30 cm and 50 cm. Dose distributions derived with CC in water phantoms of different dimensions and in a CT-based clinical breast geometry were compared to Monte Carlo (MC) simulations using the Geant4-based brachytherapy specific MC code Algebra. Agreement with MC within 1% was obtained when the dimensions of the phantom used to derive the multiple-scatter kernel were similar to those of the calculation phantom. Doses are overestimated at phantom edges when kernels are derived in larger phantoms and underestimated when derived in smaller phantoms (by around 2% to 7% depending on distance from source and phantom dimensions). CC agrees well with MC in the high dose region of a breast implant and is superior to TG43 in determining skin doses for all multiple-scatter point kernel sizes. Increased agreement between CC and MC is achieved when the point kernel is comparable to breast dimensions. The investigated approximation in multiple scatter dose depends on the choice of point kernel in relation to phantom size and yields a significant fraction of the total dose only at distances of several centimeters from a source/implant which correspond to volumes of low doses. The current implementation of the CC algorithm utilizes a point kernel derived in a comparatively large (radius 20 cm) water phantom. A fixed point kernel leads to predictable behaviour of the algorithm with the worst case being a source/implant located well within a patient/phantom

  4. Oscillating phantom in $F(R)$ gravity

    CERN Document Server

    Bamba, Kazuharu

    2009-01-01

    We investigate the oscillating effective equation of state (EoS) of the universe around the phantom divide in the framework of $F(R)$ gravity. We illustrate the behavior of $F(R)$ with realizing multiple crossings of the phantom divide.

  5. Note on the Schwarzschild-phantom wormhole

    Science.gov (United States)

    Lukmanova, R.; Khaibullina, A.; Izmailov, R.; Yanbekov, A.; Karimov, R.; Potapov, A. A.

    2016-11-01

    Recently, it has been shown by Lobo, Parsaei and Riazi that phantom energy with ω =pr/ρ Katz and Bi čák. It turns out that, even though the interior mass is positive, the integral implies repulsive energy. This is consistent with the phantom nature of interior matter.

  6. Resin phantoms as skin simulating layers

    CSIR Research Space (South Africa)

    Karsten, AE

    2011-07-01

    Full Text Available on the efficiency of Photodynamic Therapy (PDT) treatment. Two resin based solid phantoms were prepared to simulate two different skin types. Cells were prepared and PDT treatment were done on cells with and without the phantoms, by keeping the total dose delivered...

  7. Kerr-Like Phantom Wormhole

    CERN Document Server

    Miranda, Galaxia; García, Nadiezhda Motelongo

    2013-01-01

    In this work we study a Kerr-like wormhole with phantom matter as source. It has three parameters: mass, angular momentum and scalar field charge. This wormhole has a naked ring singularity, other wise it is regular everywhere. The mean feature of this wormhole is that the mouth of the throat lie on a sphere of the same radius as the ring singularity an avoids any observer to see or to reach the singularity, it behaves like an anti-horizon. We analyse the geodesics of the wormhole and find that an observer can go through the geodesics without troubles, but the equator presents an infinity potential barrier which avoids to reach the throat. From an analysis of the Riemann tensor we obtain that the tidal forces permits the wormhole to be traversable for an observer like a human being.

  8. Galactosemia and phantom absence seizures

    Directory of Open Access Journals (Sweden)

    Zeynep Aydin-Özemir

    2014-01-01

    Full Text Available Generalized and focal seizures can rarely be seen in galactosemia patients, but absence seizures were not reported previously. An 18-year-old male was diagnosed as galactosemia at the age of 8 months. No family history of epilepsy was present. His absence seizures realized at the age of 9 years. Generalized 3-4 Hz spike-wave discharges were identified in his electroencephalography. Homozygous mutation at exon 6 c. 563A > G was identified. The electroencephalogram of his sibling was unremarkable. Our aim was to present the long-term follow-up of a patient diagnosed with galactosemia, who had phantom absence seizures and typical 3-4 Hz spike-wave discharges in his electroencephalogram to draw attention to this rare association.

  9. Design, development of water tank-type lung phantom and dosimetric verification in institutions participating in a phase I study of stereotactic body radiation therapy in patients with T2N0M0 non-small cell lung cancer: Japan Clinical Oncology Group trial (JCOG0702).

    Science.gov (United States)

    Nishio, Teiji; Shirato, Hiroki; Ishikawa, Masayori; Miyabe, Yuki; Kito, Satoshi; Narita, Yuichirou; Onimaru, Rikiya; Ishikura, Satoshi; Ito, Yoshinori; Hiraoka, Masahiro

    2014-05-01

    A domestic multicenter phase I study of stereotactic body radiotherapy (SBRT) for T2N0M0 non-small cell lung cancer in inoperable patients or elderly patients who refused surgery was initiated as the Japan Clinical Oncology Group trial (JCOG0702) in Japan. Prior to the clinical study, the accuracy of dose calculation in radiation treatment-planning systems was surveyed in participating institutions, and differences in the irradiating dose between the institutions were investigated. We developed a water tank-type lung phantom appropriate for verification of the exposure dose in lung SBRT. Using this water tank-type lung phantom, the dose calculated in the radiation treatment-planning system and the measured dose using a free air ionization chamber and dosimetric film were compared in a visiting survey of the seven institutions participating in the clinical study. In all participating institutions, differences between the calculated and the measured dose in the irradiation plan were as follows: the accuracy of the absolute dose in the center of the simulated tumor measured using a free air ionization chamber was within 2%, the mean gamma value was ≤ 0.47 on gamma analysis following the local dose criteria, and the pass rate was >87% for 3%/3 mm from measurement of dose distribution with dosimetric film. These findings confirmed the accuracy of delivery doses in the institutions participating in the clinical study, so that a study with integration of the institutions could be initiated.

  10. Development of phantoms for spiral CT.

    Science.gov (United States)

    Goodenough, D J; Levy, J R; Kasales, C

    1998-01-01

    This paper reports on the development of a new phantom for spiral CT. The phantom meets the increased demands on phantom z-axis uniformity in order that objects from the CT slice, immediately above and below the CT slice of interest, do not contribute perturbing information to the reconstructed CT slice. The phantom depends on formulation of tissue-like materials that can be cast and produced in both geometric and anthropomorphic shapes with sufficient z-axis length to enable unperturbed CT slices of test objects of interest. These materials are then used to produce a series of test objects of CT image quality including low contrast samples that do not require volume averaging or mixing of solutions, and that can reflect sub-slice thickness test objects and supra-slice thickness test objects. The overall phantom and its individual test objects provides meaningful tests of spiral CT image quality including slice sensitivity, CT number linearity and tests of high and low contrast resolution. Schematic designs and actual CT scans are shown. The new spiral phantom appears to meet the increased demands of spiral CT on phantom design, particularly z-axis length, and requirements for low contrast resolution test objects.

  11. SU-E-T-124: Anthropomorphic Phantoms for Confirmation of Linear Accelerator Based Small Animal Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Perks, J; Benedict, S [UC Davis Cancer Center, Sacramento, CA (United States); Lucero, S [UC Davis, Davis, CA (United States)

    2015-06-15

    Purpose: To document the support of radiobiological small animal research by a modern radiation oncology facility. This study confirms that a standard, human use linear accelerator can cover the range of experiments called for by researchers performing animal irradiation. A number of representative, anthropomorphic murine phantoms were made. The phantoms confirmed the small field photon and electron beams dosimetry validated the use of the linear accelerator for rodents. Methods: Laser scanning a model, CAD design and 3D printing produced the phantoms. The phantoms were weighed and CT scanned to judge their compatibility to real animals. Phantoms were produced to specifically mimic lung, gut, brain, and othotopic lesion irradiations. Each phantom was irradiated with the same protocol as prescribed to the live animals. Delivered dose was measured with small field ion chambers, MOS/FETs or TLDs. Results: The density of the phantom material compared to density range across the real mice showed that the printed material would yield sufficiently accurate measurements when irradiated. The whole body, lung and gut irradiations were measured within 2% of prescribed doses with A1SL ion chamber. MOSFET measurements of electron irradiations for the orthotopic lesions allowed refinement of the measured small field output factor to better than 2% and validated the immunology experiment of irradiating one lesion and sparing another. Conclusion: Linacs are still useful tools in small animal bio-radiation research. This work demonstrated a strong role for the clinical accelerator in small animal research, facilitating standard whole body dosing as well as conformal treatments down to 1cm field. The accuracy of measured dose, was always within 5%. The electron irradiations of the phantom brain and flank tumors needed adjustment; the anthropomorphic phantoms allowed refinement of the initial output factor measurements for these fields which were made in a large block of solid water.

  12. A new, open-source, multi-modality digital breast phantom

    Science.gov (United States)

    Graff, Christian G.

    2016-03-01

    An anthropomorphic digital breast phantom has been developed with the goal of generating random voxelized breast models that capture the anatomic variability observed in vivo. This is a new phantom and is not based on existing digital breast phantoms or segmentation of patient images. It has been designed at the outset to be modality agnostic (i.e., suitable for use in modeling x-ray based imaging systems, magnetic resonance imaging, and potentially other imaging systems) and open source so that users may freely modify the phantom to suit a particular study. In this work we describe the modeling techniques that have been developed, the capabilities and novel features of this phantom, and study simulated images produced from it. Starting from a base quadric, a series of deformations are performed to create a breast with a particular volume and shape. Initial glandular compartments are generated using a Voronoi technique and a ductal tree structure with terminal duct lobular units is grown from the nipple into each compartment. An additional step involving the creation of fat and glandular lobules using a Perlin noise function is performed to create more realistic glandular/fat tissue interfaces and generate a Cooper's ligament network. A vascular tree is grown from the chest muscle into the breast tissue. Breast compression is performed using a neo-Hookean elasticity model. We show simulated mammographic and T1-weighted MRI images and study properties of these images.

  13. The reference phantoms: voxel vs polygon.

    Science.gov (United States)

    Kim, C H; Yeom, Y S; Nguyen, T T; Wang, Z J; Kim, H S; Han, M C; Lee, J K; Zankl, M; Petoussi-Henss, N; Bolch, W E; Lee, C; Chung, B S

    2016-06-01

    The International Commission on Radiological Protection (ICRP) reference male and female adult phantoms, described in Publication 110, are voxel phantoms based on whole-body computed tomography scans of a male and a female patient, respectively. The voxel in-plane resolution and the slice thickness, of the order of a few millimetres, are insufficient for proper segmentation of smaller tissues such as the lens of the eye, the skin, and the walls of some organs. The calculated doses for these tissues therefore present some limitations, particularly for weakly penetrating radiation. Similarly, the Publication 110 phantoms cannot represent 8-40-µm-thick target regions in respiratory or alimentary tract organs. Separate stylised models have been used to represent these tissues for calculation of the ICRP reference dose coefficients (DCs). ICRP Committee 2 recently initiated a research project, the ultimate goal of which is to convert the Publication 110 phantoms to a high-quality polygon-mesh (PM) format, including all source and target regions, even those of the 8-40-µm-thick alimentary and respiratory tract organs. It is expected that the converted phantoms would lead to the same or very similar DCs as the Publication 110 reference phantoms for penetrating radiation and, at the same time, provide more accurate DCs for weakly penetrating radiation and small tissues. Additionally, the reference phantoms in the PM format would be easily deformable and, as such, could serve as a starting point to create phantoms of various postures for use, for example, in accidental dose calculations. This paper will discuss the current progress of the phantom conversion project and its significance for ICRP DC calculations.

  14. The dependencies of phase velocity and dispersion on volume fraction in cancellous-bone-mimicking phantoms.

    Science.gov (United States)

    Wear, Keith A

    2009-02-01

    Frequency-dependent phase velocity was measured in eight cancellous-bone-mimicking phantoms consisting of suspensions of randomly oriented nylon filaments (simulating trabeculae) in a soft-tissue-mimicking medium (simulating marrow). Trabecular thicknesses ranged from 152 to 356 mum. Volume fractions of nylon filament material ranged from 0% to 10%. Phase velocity varied approximately linearly with frequency over the range from 300 to 700 kHz. The increase in phase velocity (compared with phase velocity in a phantom containing no filaments) at 500 kHz was approximately proportional to volume fraction occupied by nylon filaments. The derivative of phase velocity with respect to frequency was negative and exhibited nonlinear, monotonically decreasing dependence on volume fraction. The dependencies of phase velocity and its derivative on volume fraction in these phantoms were similar to those reported in previous studies on (1) human cancellous bone and (2) phantoms consisting of parallel nylon wires immersed in water.

  15. Charged black holes in phantom cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Jamil, Mubasher; Qadir, Asghar; Rashid, Muneer Ahmad [National University of Sciences and Technology, Center for Advanced Mathematics and Physics, Rawalpindi (Pakistan)

    2008-11-15

    In the classical relativistic regime, the accretion of phantom-like dark energy onto a stationary black hole reduces the mass of the black hole. We have investigated the accretion of phantom energy onto a stationary charged black hole and have determined the condition under which this accretion is possible. This condition restricts the mass-to-charge ratio in a narrow range. This condition also challenges the validity of the cosmic-censorship conjecture since a naked singularity is eventually produced due to accretion of phantom energy onto black hole. (orig.)

  16. Characterization of a novel phantom for three-dimensional in vitro cell experiments

    Energy Technology Data Exchange (ETDEWEB)

    Altman, Michael B; Pelizzari, Charles A; Aydogan, Bulent; Reft, Chester S; Chmura, Steven J [Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL (United States); Vesper, Benjamin J; Radosevich, James A [Center for Molecular Biology of Oral Diseases, College of Dentistry, University of Illinois at Chicago, Chicago, IL (United States); Smith, Brett D; Stinauer, Michelle A [Department of Radiation Oncology, University of Illinois at Chicago, Chicago, IL (United States); Roeske, John C [Department of Radiation Oncology, Loyola University Medical Center, Maywood, IL (United States)

    2009-03-07

    A novel intensity-modulated radiation therapy (IMRT) phantom for use in three-dimensional in vitro cell experiments, based on a commercially available system (CIRS Inc., Norfolk, VA), was designed and fabricated. The water-equivalent plastic phantom can, with a set of water-equivalent plastic inserts, enclose 1-3 multi-well tissue culture plates. Dosimetry within the phantom was assessed using thermoluminescence dosimeters (TLDs) and film. The phantom was loaded with three tissue culture plates, and an array of TLDs or a set of three films was placed underneath each plate within the phantom, and then irradiated using an IMRT plan created for it. Measured doses from each dosimeter were compared to those acquired from the treatment planning system. The percent differences between TLD measurements and the corresponding points in the treatment plan ranged from 1.3% to 2.9%, differences which did not show statistical significance. Average point-by-point percent dose differences for each film plane ranged from 1.6% to 3.1%. The percentage dose difference for which 95% of the points in the film matched those corresponding to the calculated dose plane to within 3.0% ranged from 2.8% to 4.2%. The good agreement between predicted and measured dose shows that the phantom is a useful and efficient tool for three-dimensional in vitro cell experiments. (note)

  17. Strategies of the Poorest in Local Water Conflict and Cooperation – Evidence from Vietnam, Bolivia and Zambia

    Directory of Open Access Journals (Sweden)

    M. Funder

    2012-02-01

    Full Text Available Media stories often speak of a future dominated by large-scale water wars. Rather less attention has been paid to the way water conflicts play out at local levels and form part of people’s everyday lives. Based on case study studies from Vietnam, Bolivia and Zambia, this paper examines the strategies of poor households in local water conflicts. It is shown how such households may not only engage actively in collaborative water management but may also apply risk aversion strategies when faced with powerful adversaries in conflict situations. It is further shown how dependency relations between poor and wealthy households can reduce the scope of action for the poor in water conflicts. As a result, poor households can be forced to abstain from defending their water resources in order to maintain socio-economic and political ties with the very same households that oppose them in water conflicts. The paper concludes by briefly discussing how the poorest can be supported in local water conflicts. This includes ensuring that alternative spaces for expressing grievances exist and are accessible; facilitating that water sharing agreements and rights are clearly stipulated and monitored; and working beyond water governance to reduce the socio-economic dependency-relations of poor households.

  18. Monte Carlo study of conversion factors for ionization chamber dosimetry in solid slab phantoms for MV photon beams

    Science.gov (United States)

    Park, Dong-wook; Lee, Jai-ki

    2016-08-01

    For high energy photon beams, solid phantom to water dose conversion factors were calculated by using a Monte Carlo method, and the result were compared with measurements and published data. Based on the absorbed dose to water dosimetry protocol, the conversion factor was theoretically divided into stopping powers ratios, perturbation factors and ratios of absorbed dose to water and that to solid phantom. Data for a Farmer-type chamber and a solid phantom based on polystyrene which is one of the most common material were applied to calculate the conversion factors for 6 MV and 15 MV photon beams. All measurements were conducted after 10 Gy pre-irradiation and thermal equilibrium had been established with solid slabs in a treatment room. The calculated and the measured conversion factors were in good agreement and could be used to confirm the feasibility of the solid phantom as a substitute for water for high energy photon beam.

  19. Can neural blocks prevent phantom limb pain?

    Science.gov (United States)

    Borghi, Battista; D'Addabbo, Marco; Borghi, Raffaele

    2014-07-01

    Phantom limb syndrome (PLS) is a syndrome including stump pain, phantom limb pain and not-painful phantom sensations, which involves a large part of amputee patients and often has devastating effects on their quality of life. The efficacy of standard therapies is very poor. Nerve blocks have been investigated for the treatment and prevention of PLS. Epidural and peripheral blocks limited to the first three postamputation days can only reduce acute pain but cannot prevent the later development of PLS. Recent studies have shown that ambulatory prolonged peripheral nerve block (up to 30 days postamputation) may represent a new possible option to treat phantom pain and prevent the development of PLS and chronic pain.

  20. Phantom cosmology without Big Rip singularity

    Energy Technology Data Exchange (ETDEWEB)

    Astashenok, Artyom V. [Baltic Federal University of I. Kant, Department of Theoretical Physics, 236041, 14, Nevsky st., Kaliningrad (Russian Federation); Nojiri, Shin' ichi, E-mail: nojiri@phys.nagoya-u.ac.jp [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602 (Japan); Odintsov, Sergei D. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Institucio Catalana de Recerca i Estudis Avancats - ICREA and Institut de Ciencies de l' Espai (IEEC-CSIC), Campus UAB, Facultat de Ciencies, Torre C5-Par-2a pl, E-08193 Bellaterra (Barcelona) (Spain); Tomsk State Pedagogical University, Tomsk (Russian Federation); Yurov, Artyom V. [Baltic Federal University of I. Kant, Department of Theoretical Physics, 236041, 14, Nevsky st., Kaliningrad (Russian Federation)

    2012-03-23

    We construct phantom energy models with the equation of state parameter w which is less than -1, w<-1, but finite-time future singularity does not occur. Such models can be divided into two classes: (i) energy density increases with time ('phantom energy' without 'Big Rip' singularity) and (ii) energy density tends to constant value with time ('cosmological constant' with asymptotically de Sitter evolution). The disintegration of bound structure is confirmed in Little Rip cosmology. Surprisingly, we find that such disintegration (on example of Sun-Earth system) may occur even in asymptotically de Sitter phantom universe consistent with observational data. We also demonstrate that non-singular phantom models admit wormhole solutions as well as possibility of Big Trip via wormholes.

  1. Custom molded thermal MRg-FUS phantom

    Science.gov (United States)

    Eames, Matthew D. C.; Snell, John W.; Hananel, Arik; Kassell, Neal F.

    2012-11-01

    This article describes a method for creating custom-molded thermal phantoms for use with MR-guided focused ultrasound systems. The method is defined here for intracranial applications, though it may be modified for other anatomical targets.

  2. Open environmental data sets - prospect of co-operation between public and private sector in water quality monitoring. Final report of Water Quality Service for Lakes -project; Avoin ympaeristoetieto - yhteistyoen kehittaeminen vesistoejen seurannassa. Jaervien vedenlaatupalvelu -hankkeen loppuraportti

    Energy Technology Data Exchange (ETDEWEB)

    Anttila, S.; Broeckl, M.; Herlevi, A. (and others)

    2012-04-15

    Data sets collected by the public sector are common property and should be freely available. Effective usage of this open data is anticipated to create new information and services, but also to develop welfare for humans. Insufficient usage of public and open environmental data sets in the private sector has been recognized as a problem. Reasons for this can be found from the non-commercial nature of environmental data, the way it is collected and archived, but also from the strong role of public sector in this field. In the Water Quality Service for Lakes -project (Tekes, 2009-2012), we wanted to advance the utilization of the public data sets in the private sector, as well as to promote the co-operation between these two sectors. Starting point was to develop local research infrastructure in the way that collected information would be easily accessible to private companies. This was realized by creating a data base that gathers water quality information from several data sources and provides a standardized interface for the data utilization. In addition, project provided a variety of research results including a questionnaire survey targeted to the users of water quality information, and the methods to increase the accuracy of collected data and to create forecasts from it. A concrete result from the project was also the development of 'laymans' water quality measurement device named as Secchi3000. A digital camera installed in e.g. mobile phones can be used with Secchi3000 device to measure water quality of different natural waters. This new innovation has great potential in e.g. citizen based monitoring. The challenges and opportunities to create business based on the public environmental data were revolved in two work shops. In this publication the prospects of co-operation between public and private sector are discussed based on the results of the Water Quality Service for lakes -project. (orig.)

  3. Development of realistic physical breast phantoms matched to virtual breast phantoms based on human subject data.

    Science.gov (United States)

    Kiarashi, Nooshin; Nolte, Adam C; Sturgeon, Gregory M; Segars, William P; Ghate, Sujata V; Nolte, Loren W; Samei, Ehsan; Lo, Joseph Y

    2015-07-01

    Physical phantoms are essential for the development, optimization, and evaluation of x-ray breast imaging systems. Recognizing the major effect of anatomy on image quality and clinical performance, such phantoms should ideally reflect the three-dimensional structure of the human breast. Currently, there is no commercially available three-dimensional physical breast phantom that is anthropomorphic. The authors present the development of a new suite of physical breast phantoms based on human data. The phantoms were designed to match the extended cardiac-torso virtual breast phantoms that were based on dedicated breast computed tomography images of human subjects. The phantoms were fabricated by high-resolution multimaterial additive manufacturing (3D printing) technology. The glandular equivalency of the photopolymer materials was measured relative to breast tissue-equivalent plastic materials. Based on the current state-of-the-art in the technology and available materials, two variations were fabricated. The first was a dual-material phantom, the Doublet. Fibroglandular tissue and skin were represented by the most radiographically dense material available; adipose tissue was represented by the least radiographically dense material. The second variation, the Singlet, was fabricated with a single material to represent fibroglandular tissue and skin. It was subsequently filled with adipose-equivalent materials including oil, beeswax, and permanent urethane-based polymer. Simulated microcalcification clusters were further included in the phantoms via crushed eggshells. The phantoms were imaged and characterized visually and quantitatively. The mammographic projections and tomosynthesis reconstructed images of the fabricated phantoms yielded realistic breast background. The mammograms of the phantoms demonstrated close correlation with simulated mammographic projection images of the corresponding virtual phantoms. Furthermore, power-law descriptions of the phantom images

  4. Development of realistic physical breast phantoms matched to virtual breast phantoms based on human subject data

    Energy Technology Data Exchange (ETDEWEB)

    Kiarashi, Nooshin [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 and Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Nolte, Adam C. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Sturgeon, Gregory M.; Ghate, Sujata V. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Segars, William P. [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 and Medical Physics Graduate Program, Duke University, Durham, North Carolina 27708 (United States); Nolte, Loren W. [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 and Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Samei, Ehsan [Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States); Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, Duke University, Durham, North Carolina 27708 (United States); and others

    2015-07-15

    Purpose: Physical phantoms are essential for the development, optimization, and evaluation of x-ray breast imaging systems. Recognizing the major effect of anatomy on image quality and clinical performance, such phantoms should ideally reflect the three-dimensional structure of the human breast. Currently, there is no commercially available three-dimensional physical breast phantom that is anthropomorphic. The authors present the development of a new suite of physical breast phantoms based on human data. Methods: The phantoms were designed to match the extended cardiac-torso virtual breast phantoms that were based on dedicated breast computed tomography images of human subjects. The phantoms were fabricated by high-resolution multimaterial additive manufacturing (3D printing) technology. The glandular equivalency of the photopolymer materials was measured relative to breast tissue-equivalent plastic materials. Based on the current state-of-the-art in the technology and available materials, two variations were fabricated. The first was a dual-material phantom, the Doublet. Fibroglandular tissue and skin were represented by the most radiographically dense material available; adipose tissue was represented by the least radiographically dense material. The second variation, the Singlet, was fabricated with a single material to represent fibroglandular tissue and skin. It was subsequently filled with adipose-equivalent materials including oil, beeswax, and permanent urethane-based polymer. Simulated microcalcification clusters were further included in the phantoms via crushed eggshells. The phantoms were imaged and characterized visually and quantitatively. Results: The mammographic projections and tomosynthesis reconstructed images of the fabricated phantoms yielded realistic breast background. The mammograms of the phantoms demonstrated close correlation with simulated mammographic projection images of the corresponding virtual phantoms. Furthermore, power

  5. Acupuncture treatment of phantom limb pain and phantom limb sensation in a primary care setting.

    Science.gov (United States)

    Davies, Arwel

    2013-03-01

    A 45-year-old man presented with phantom limb pain and phantom limb sensation 12 weeks after an above-elbow amputation of his right arm. He underwent seven sessions of acupuncture at weekly intervals carried out by his general practitioner on his intact left arm, with complete relief of the phantom limb pain and considerable improvement of the phantom limb sensation of his right arm. This case demonstrates the possible benefits from the use of short acupuncture sessions for a potentially chronic condition undertaken within the constraints of a busy general medical practice.

  6. Conversion of ICRP male reference phantom to polygon-surface phantom

    Science.gov (United States)

    Yeom, Yeon Soo; Han, Min Cheol; Kim, Chan Hyeong; Jeong, Jong Hwi

    2013-10-01

    The International Commission on Radiological Protection (ICRP) reference phantoms, developed based on computed tomography images of human bodies, provide much more realism of human anatomy than the previously used MIRD5 (Medical Internal Radiation Dose) mathematical phantoms. It has been, however, realized that the ICRP reference phantoms have some critical limitations showing a considerable amount of holes for the skin and wall organs mainly due to the nature of voxels of which the phantoms are made, especially due to their low voxel resolutions. To address this problem, we are planning to develop the polygon-surface version of ICRP reference phantoms by directly converting the ICRP reference phantoms (voxel phantoms) to polygon-surface phantoms. The objective of this preliminary study is to see if it is indeed possible to construct the high-quality polygon-surface phantoms based on the ICRP reference phantoms maintaining identical organ morphology and also to identify any potential issues, and technologies to address these issues, in advance. For this purpose, in the present study, the ICRP reference male phantom was roughly converted to a polygon-surface phantom. Then, the constructed phantom was implemented in Geant4, Monte Carlo particle transport code, for dose calculations, and the calculated dose values were compared with those of the original ICRP reference phantom to see how much the calculated dose values are sensitive to the accuracy of the conversion process. The results of the present study show that it is certainly possible to convert the ICRP reference phantoms to surface phantoms with enough accuracy. In spite of using relatively less resources (<2 man-months), we were able to construct the polygon-surface phantom with the organ masses perfectly matching the ICRP reference values. The analysis of the calculated dose values also implies that the dose values are indeed not very sensitive to the detailed morphology of the organ models in the phantom

  7. Phantom Limb Pain: Mechanisms and Treatment Approaches

    Directory of Open Access Journals (Sweden)

    Bishnu Subedi

    2011-01-01

    Full Text Available The vast amount of research over the past decades has significantly added to our knowledge of phantom limb pain. Multiple factors including site of amputation or presence of preamputation pain have been found to have a positive correlation with the development of phantom limb pain. The paradigms of proposed mechanisms have shifted over the past years from the psychogenic theory to peripheral and central neural changes involving cortical reorganization. More recently, the role of mirror neurons in the brain has been proposed in the generation of phantom pain. A wide variety of treatment approaches have been employed, but mechanism-based specific treatment guidelines are yet to evolve. Phantom limb pain is considered a neuropathic pain, and most treatment recommendations are based on recommendations for neuropathic pain syndromes. Mirror therapy, a relatively recently proposed therapy for phantom limb pain, has mixed results in randomized controlled trials. Most successful treatment outcomes include multidisciplinary measures. This paper attempts to review and summarize recent research relative to the proposed mechanisms of and treatments for phantom limb pain.

  8. Development of a neonatal skull phantom for photoacoustic imaging

    Science.gov (United States)

    Tavakolian, Pantea; Todd, Rhiannon; Kosik, Ivan; Chamson-Reig, Astrid; Vasefi, Fartash; St. Lawrence, Keith; Carson, Jeffrey J. L.

    2013-03-01

    Photoacoustic imaging (PAI) has been proposed as a non-invasive technique for the diagnosis and monitoring of disorders in the neonatal brain. However, PAI of the brain through the intact skull is challenging due to reflection and attenuation of photoacoustic pressure waves by the skull bone. The objective of this work was to develop a phantom for testing the potential limits the skull bone places on PAI of the neonatal brain. Our approach was to make acoustic measurements on materials designed to mimic the neonatal skull bone and construct a semi-realistic phantom. A water tank and two ultrasound transducers were utilized to measure the ultrasound insertion loss (100 kHz to 5MHz) of several materials. Cured mixtures of epoxy and titanium dioxide powder provided the closest acoustic match to neonatal skull bone. Specifically, a 1.4-mm thick sample composed of 50% (by mass) titanium dioxide powder and 50% epoxy was closest to neonatal skull bone in terms of acoustic insertion loss. A hemispherical skull phantom (1.4 mm skull thickness) was made by curing the epoxy/titanium dioxide powder mixture inside a mold. The mold was constructed using 3D prototyping techniques and was based on the hairless head of a realistic infant doll. The head was scanned to generate a 3D model, which in turn was used to build a 3D CAD version of the mold. The mold was CNC machined from two solid blocks of Teflon®. The neonatal skull phantom will enable the study of the propagation of photoacoustic pressure waves under a variety of experimental conditions.

  9. Dynamic heart phantom with functional mitral and aortic valves

    Science.gov (United States)

    Vannelli, Claire; Moore, John; McLeod, Jonathan; Ceh, Dennis; Peters, Terry

    2015-03-01

    Cardiac valvular stenosis, prolapse and regurgitation are increasingly common conditions, particularly in an elderly population with limited potential for on-pump cardiac surgery. NeoChord©, MitraClipand numerous stent-based transcatheter aortic valve implantation (TAVI) devices provide an alternative to intrusive cardiac operations; performed while the heart is beating, these procedures require surgeons and cardiologists to learn new image-guidance based techniques. Developing these visual aids and protocols is a challenging task that benefits from sophisticated simulators. Existing models lack features needed to simulate off-pump valvular procedures: functional, dynamic valves, apical and vascular access, and user flexibility for different activation patterns such as variable heart rates and rapid pacing. We present a left ventricle phantom with these characteristics. The phantom can be used to simulate valvular repair and replacement procedures with magnetic tracking, augmented reality, fluoroscopy and ultrasound guidance. This tool serves as a platform to develop image-guidance and image processing techniques required for a range of minimally invasive cardiac interventions. The phantom mimics in vivo mitral and aortic valve motion, permitting realistic ultrasound images of these components to be acquired. It also has a physiological realistic left ventricular ejection fraction of 50%. Given its realistic imaging properties and non-biodegradable composition—silicone for tissue, water for blood—the system promises to reduce the number of animal trials required to develop image guidance applications for valvular repair and replacement. The phantom has been used in validation studies for both TAVI image-guidance techniques1, and image-based mitral valve tracking algorithms2.

  10. Stable phantom materials for ultrasound and optical imaging

    Science.gov (United States)

    Cabrelli, Luciana C.; Pelissari, Pedro I. B. G. B.; Deana, Alessandro M.; Carneiro, Antonio A. O.; Pavan, Theo Z.

    2017-01-01

    Phantoms mimicking the specific properties of biological tissues are essential to fully characterize medical devices. Water-based materials are commonly used to manufacture phantoms for ultrasound and optical imaging techniques. However, these materials have disadvantages, such as easy degradation and low temporal stability. In this study, we propose an oil-based new tissue-mimicking material for ultrasound and optical imaging, with the advantage of presenting low temporal degradation. A styrene-ethylene/butylene-styrene (SEBS) copolymer in mineral oil samples was made varying the SEBS concentration between 5%-15%, and low-density polyethylene (LDPE) between 0%-9%. Acoustic properties, such as the speed of sound and the attenuation coefficient, were obtained using frequencies ranging from 1-10 MHz, and were consistent with that of soft tissues. These properties were controlled varying SEBS and LDPE concentration. To characterize the optical properties of the samples, the diffuse reflectance and transmittance were measured. Scattering and absorption coefficients ranging from 400 nm-1200 nm were calculated for each compound. SEBS gels are a translucent material presenting low optical absorption and scattering coefficients in the visible region of the spectrum, but the presence of LDPE increased the turbidity. Adding LDPE increased the absorption and scattering of the phantom materials. Ultrasound and photoacoustic images of a heterogeneous phantom made of LDPE/SEBS containing a spherical inclusion were obtained. Annatto dye was added to the inclusion to enhance the optical absorbance. The results suggest that copolymer gels are promising for ultrasound and optical imaging, making them also potentially useful for photoacoustic imaging.

  11. Attenuation properties and percentage depth dose of tannin-based Rhizophora spp. particleboard phantoms using computed tomography (CT) and treatment planning system (TPS) at high energy x-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Yusof, M. F. Mohd, E-mail: mfahmi@usm.my [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); School of Health Sciences, Universiti Sains Malaysia, 16150 Kota Bharu, Kelantan (Malaysia); Abdullah, R. [School of Health Sciences, Universiti Sains Malaysia, 16150 Kota Bharu, Kelantan (Malaysia); Tajuddin, A. A. [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200 Kepala Batas, Penang (Malaysia); Hashim, R. [School of Industrial Technologies, Universiti Sains Malaysia, 11800 Penang (Malaysia); Bauk, S. [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2016-01-22

    A set of tannin-based Rhizophora spp. particleboard phantoms with dimension of 30 cm x 30 cm was fabricated at target density of 1.0 g/cm{sup 3}. The mass attenuation coefficient of the phantom was measured using {sup 60}Co gamma source. The phantoms were scanned using Computed Tomography (CT) scanner and the percentage depth dose (PDD) of the phantom was calculated using treatment planning system (TPS) at 6 MV and 10 MV x-ray and compared to that in solid water phantoms. The result showed that the mass attenuation coefficient of tannin-based Rhizohora spp. phantoms was near to the value of water with χ{sup 2} value of 1.2. The measured PDD also showed good agreement with solid water phantom at both 6 MV and 10 MV x-ray with percentage deviation below 8% at depth beyond the maximum dose, Z{sub max}.

  12. Water mediated ligand functional group cooperativity: the contribution of a methyl group to binding affinity is enhanced by a COO(-) group through changes in the structure and thermodynamics of the hydration waters of ligand-thermolysin complexes.

    Science.gov (United States)

    Nasief, Nader N; Tan, Hongwei; Kong, Jing; Hangauer, David

    2012-10-11

    Ligand functional groups can modulate the contributions of one another to the ligand-protein binding thermodynamics, producing either positive or negative cooperativity. Data presented for four thermolysin phosphonamidate inhibitors demonstrate that the differential binding free energy and enthalpy caused by replacement of a H with a Me group, which binds in the well-hydrated S2' pocket, are more favorable in presence of a ligand carboxylate. The differential entropy is however less favorable. Dissection of these differential thermodynamic parameters, X-ray crystallography, and density-functional theory calculations suggest that these cooperativities are caused by variations in the thermodynamics of the complex hydration shell changes accompanying the H→Me replacement. Specifically, the COO(-) reduces both the enthalpic penalty and the entropic advantage of displacing water molecules from the S2' pocket and causes a subsequent acquisition of a more enthalpically, less entropically, favorable water network. This study contributes to understanding the important role water plays in ligand-protein binding.

  13. Results from the Italian participation in the International Co-operative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes (ICP Waters

    Directory of Open Access Journals (Sweden)

    Gabriele A. TARTARI

    2000-02-01

    Full Text Available This paper describes the research activity carried out by the Istituto Italiano di Idrobiologia of the CNR, on behalf of the Ministero dell'Ambiente, Servizio Inquinamento Atmosferico e Acustico, in the context of the Italian participation in the International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes (ICP Waters. Atmospheric deposition chemistry shows that nitrate increased and sulphate decreased in the 70's and 80's, while acidity started to decrease in the early 90's. The studied rivers and lakes show variations in sulphate and nitrate in agreement with those of atmospheric deposition. Alkalinity is mainly determined by watershed geo-lithology and is always present in the studied lakes and streams; the lowest values of 0-10 μeq l-1 are measured in the high altitude Lake Paione Superiore, which however shows an increasing trend of alkalinity and pH.

  14. Report for fiscal 1994 on commissioned operation for research cooperation related to simplified purification system for industrial waste water; 1994 nendo sangyo haisui nado no kan'i joka system ni kansuru kenkyu kyoryoku hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-03-01

    With an objective to serve for environmental preservation in developing countries, joint researches have been performed on anaerobic waste water treatment systems utilizing bio-technology. This paper summarizes the achievements in fiscal 1994. In the research cooperation with Thailand, a reactor applicability test was performed by using a pilot plant to determine the operating conditions, and necessary data were obtained. The pilot plant was completed of installation in November. In the research cooperation with Indonesia, Tofu manufacturing waste water was selected as the object of pilot plant research. In the detailed design the Tofu manufacturing waste water shall be treated anaerobically, and the kitchen waste water shall be treated aerobically to acquire the intended water quality. In the research cooperation with Malaysia, as a result of visiting six industries and 22 factories for investigation, waste waters from chemical and foodstuff factories were selected as the object waste waters for the research. Three researchers from Thailand and Indonesia respectively were received in Japan to provide education including experimental training and visits to waste water treatment facilities. (NEDO)

  15. ENHANCING COOPERATION

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    China and Japan can cooperate on a wide scope of issues, such as the organization of the Beijing Olympic Games next year and aid to Africa,said Ide Keiji, Minister of Public Relations, Press, Culture, Education and Sports and Spokesperson of the Embassy

  16. Data collection for cooperative water resources modeling in the Lower Rio Grande Basin, Fort Quitman to the Gulf of Mexico.

    Energy Technology Data Exchange (ETDEWEB)

    Passell, Howard David; Pallachula, Kiran (GRAM, Inc., Albuquerque, NM); Tidwell, Vincent Carroll; Villalobos, Joshua (Texas A& M University); Piccinni, Giovanni (Texas A& M University); Brainard, James Robert; Gerik, Thomas (Texas A& M University); Morrison, Wendy (Texas A& M University); Serrat-Capdevila, Aleix (University of Arizona); Valdes, Juan (University of Arizona); Sheng, Zhuping (Texas A& M University); Lovato, Rene (Instituto Mexicano de Tecnologia del Agua); Guitron, Alberto (Instituto Mexicano de Tecnologia del Agua); Ennis, Martha Lee; Aparicio, Javier (Instituto Mexicano de Tecnologia del Agua); Newman, Gretchen Carr (GRAM, Inc., Albuquerque, NM); Michelsen, Ari M. (Texas A& M University)

    2004-10-01

    Water resource scarcity around the world is driving the need for the development of simulation models that can assist in water resources management. Transboundary water resources are receiving special attention because of the potential for conflict over scarce shared water resources. The Rio Grande/Rio Bravo along the U.S./Mexican border is an example of a scarce, transboundary water resource over which conflict has already begun. The data collection and modeling effort described in this report aims at developing methods for international collaboration, data collection, data integration and modeling for simulating geographically large and diverse international watersheds, with a special focus on the Rio Grande/Rio Bravo. This report describes the basin, and the data collected. This data collection effort was spatially aggregated across five reaches consisting of Fort Quitman to Presidio, the Rio Conchos, Presidio to Amistad Dam, Amistad Dam to Falcon Dam, and Falcon Dam to the Gulf of Mexico. This report represents a nine-month effort made in FY04, during which time the model was not completed.

  17. Adjustable fetal phantom for pulse oximetry

    Science.gov (United States)

    Stubán, Norbert; Niwayama, Masatsugu

    2009-05-01

    As the measuring head of a fetal pulse oximeter must be attached to the head of the fetus inside the mother's uterus during labor, testing, and developing of fetal pulse oximeters in real environment have several difficulties. A fetal phantom could enable evaluation of pulse oximeters in a simulated environment without the restrictions and difficultness of medical experiments in the labor room. Based on anatomic data we developed an adjustable fetal head phantom with three different tissue layers and artificial arteries. The phantom consisted of two arteries with an inner diameter of 0.2 and 0.4 mm. An electronically controlled pump produced pulse waves in the arteries. With the phantom we investigated the sensitivity of a custom-designed wireless pulse oximeter at different pulsation intensity and artery diameters. The results showed that the oximeter was capable of identifying 4% and 2% changes in diameter between the diastolic and systolic point in arteries of over 0.2 and 0.4 mm inner diameter, respectively. As the structure of the phantom is based on reported anatomic values, the results predict that the investigated custom-designed wireless pulse oximeter has sufficient sensitivity to detect the pulse waves and to calculate the R rate on the fetal head.

  18. Pharmacological interventions for phantom limb pain

    Institute of Scientific and Technical Information of China (English)

    FANG Jun; LIAN Yan-hong; XIE Kang-jie; CAI Shu-nü

    2013-01-01

    Objective To review the mechanisms and current clinical application of pharmacological interventions for phantom limb pain.Data sources Both Chinese and English language literatures were searched using MEDLINE (1982-2011),Pubmed (1982-2011) and the Index of Chinese Language Literature (1982-2011).Study selection Data from published articles about pharmacological management of phantom limb pain in recent domestic and foreign literature were selected.Data extraction Data were mainly extracted from 96 articles which are listed in the reference section of this review.Results By reviewing the mechanisms and current clinical application of pharmacological interventions for phantom limb pain,including anticonvulsants,antidepressants,local anaesthetics,N-methyl-D-aspartate receptor antagonists,non-steroidal anti-inflammatory drugs,tramadol,opioids,calcitonin,capsaicin,beta-adrenergic blockers,clonidine,muscle relaxants,and emerging drugs,we examined the efficacy and safety of these medications,outlined the limitations and future directions.Conclusions Although there is lack of evidence-based consensus guidelines for the pharmacological management of phantom limb pain,we recommend tricyclic antidepressants,gabapentin,tramadol,opioids,local anaesthetics and N-methyl-D-aspartate receptor antagonists as the rational options for the treatment of phantom limb pain.

  19. Monte-Carlo simulation of the SL-ELEKTA-20 medical linear accelerator. Dosimetric study of a water phantom; Simulation Monte Carlo de l'accelerateur lineaire clinique SL-ELEKTA 20. Etude dosimetrique dans un fantome d'eau

    Energy Technology Data Exchange (ETDEWEB)

    Thiam, Ch. O

    2003-06-01

    In radiotherapy, it is essential to have a precise knowledge of the dose delivered in the target volume and the neighbouring critical organs. To be usable clinically, the models of calculation must take into account the exact characteristics of the beams used and the densities of fabrics. Today we can use sophisticated irradiation techniques and get a more precise assessment of the dose and with a better knowledge of its distribution. Thus in this report, will be detailed a simulation of the head of irradiation of accelerator SL-ELEKTA-20 in electrons mode and a dosimetric study of a water phantom. This study is carried out with the code of simulation Monte Carlo GATE adapted for applications of medical physics; the results are compared with the data obtained by the anticancer center 'Jean Perrin' on a similar accelerator. (author)

  20. Application of GEANT4 radiation transport toolkit to dose calculations in anthropomorphic phantoms

    CERN Document Server

    Rodrigues, P; Peralta, L; Alves, C; Chaves, A; Lopes, M C

    2003-01-01

    In this paper we present the implementation of a dose calculation application, based on the GEANT4 Monte Carlo toolkit. Validation studies were performed with an homogeneous water phantom and an Alderson--Rando anthropomorphic phantom both irradiated with high--energy photon beams produced by a clinical linear accelerator. As input, this tool requires computer tomography images for automatic codification of voxel based geometries and phase space distributions to characterize the incident radiation field. Simulation results were compared with ionization chamber, thermoluminescent dosimetry data and commercial treatment planning system calculations. In homogeneous water phantom, overall agreement with measurements were within 1--2%. For anthropomorphic simulated setups (thorax and head irradiation) mean differences between GEANT4 and TLD measurements were less than 2%. Significant differences between GEANT4 and a semi--analytical algorithm implemented in the treatment planning system, were found in low density ...

  1. “Playing the game”, identity and perception-of-the-other in water cooperation in the Jordan River Basin

    DEFF Research Database (Denmark)

    Wessels, Josepha Ivanka

    2015-01-01

    The concept of Integrated Water Resource Management (IWRM) has enjoyed immense popularity and thus has been the preferred approach for river basin management. IWRM generally has a strong focus on rational choice, based on a technocratic conceptual interpretation of the conventional hydrological c...

  2. Report for fiscal 1995 on commissioned operation for research cooperation related to simplified purification system for industrial waste water; 1995 nendo sangyo haisui nado no kan'i joka system ni kansuru kenkyu kyoryoku hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    With an objective to serve for environmental preservation in developing countries, joint researches have been performed on anaerobic waste water treatment systems utilizing bio-technology. This paper summarizes the achievements in fiscal 1995. In the research cooperation with Thailand, a bench scale testing equipment was used to verify activity of granules, and granulation tests were performed. In the operation research by using a pilot plant, abrupt variation in quality of the feed waste water was encountered, whereas both of the fixed bed system and the UASB system have not reached the stage of tests at the targeted load. In the research cooperation with Indonesia, the actual waste water test in the laboratory scale verified that Tofu manufacturing waste water may be easily decomposed anaerobically, and the kitchen waste water aerobically. The bench scale test is in continuation on actual waste waters by experimenting the applicability of the fixed bed and UASB reactors. In the research cooperation with Malaysia, analysis was performed on chemical factory waste water properties, and so was the anaerobic treatment characteristics test in the laboratory scale. In addition, a preliminary experiment using the bench scale testing device was begun. (NEDO)

  3. Cooperative protein structural dynamics of homodimeric hemoglobin linked to water cluster at subunit interface revealed by time-resolved X-ray solution scattering.

    Science.gov (United States)

    Kim, Jong Goo; Muniyappan, Srinivasan; Oang, Key Young; Kim, Tae Wu; Yang, Cheolhee; Kim, Kyung Hwan; Kim, Jeongho; Ihee, Hyotcherl

    2016-03-01

    Homodimeric hemoglobin (HbI) consisting of two subunits is a good model system for investigating the allosteric structural transition as it exhibits cooperativity in ligand binding. In this work, as an effort to extend our previous study on wild-type and F97Y mutant HbI, we investigate structural dynamics of a mutant HbI in solution to examine the role of well-organized interfacial water cluster, which has been known to mediate intersubunit communication in HbI. In the T72V mutant of HbI, the interfacial water cluster in the T state is perturbed due to the lack of Thr72, resulting in two less interfacial water molecules than in wild-type HbI. By performing picosecond time-resolved X-ray solution scattering experiment and kinetic analysis on the T72V mutant, we identify three structurally distinct intermediates (I1, I2, and I3) and show that the kinetics of the T72V mutant are well described by the same kinetic model used for wild-type and F97Y HbI, which involves biphasic kinetics, geminate recombination, and bimolecular CO recombination. The optimized kinetic model shows that the R-T transition and bimolecular CO recombination are faster in the T72V mutant than in the wild type. From structural analysis using species-associated difference scattering curves for the intermediates, we find that the T-like deoxy I3 intermediate in solution has a different structure from deoxy HbI in crystal. In addition, we extract detailed structural parameters of the intermediates such as E-F distance, intersubunit rotation angle, and heme-heme distance. By comparing the structures of protein intermediates in wild-type HbI and the T72V mutant, we reveal how the perturbation in the interfacial water cluster affects the kinetics and structures of reaction intermediates of HbI.

  4. The three dimensional map of dose components in a head phantom for boron neutron capture therapy

    Directory of Open Access Journals (Sweden)

    Bavarnegin Elham

    2013-01-01

    Full Text Available The in-phantom measurement of physical dose distribution and construction of a convenient phantom is very important for boron neutron capture therapy planning validation. In this study we have simulated a head phantom, suggested for construction in boron neutron capture therapy facilities, and calculated all relevant dose components inside of it using the Monte Carlo code MCNPX. A “generic” epithermal neutron beam with a broad neutron spectrum, similar to beams used for neutron capture therapy clinical trials, was used. The calculated distributions of all relevant dose components in brain tissue equivalent were compared with those in water. The results show that water is a suitable dosimetry material and that the simulated head phantom is a suitable design for producing accurate three-dimensional maps of dose components at enough points inside of the phantom for boron neutron capture therapy dosimetry measurements and the use of these dose maps in beam development and benchmarking of computer-based treatment codes.

  5. Phantom evolving wormholes with big rip singularities

    CERN Document Server

    Cataldo, Mauricio

    2013-01-01

    We investigate a family of inhomogeneous and anisotropic gravitational fields exhibiting a future singularity at a finite value of the proper time. The studied spherically symmetric spacetimes are asymptotically Friedmann-Robertson-Walker at spatial infinity and describe wormhole configurations filled with two matter components: one inhomogeneous and anisotropic fluid and another isotropic and homogeneously distributed fluid, characterized by the supernegative equation of state \\omega=p/\\rho < -1. In previously constructed wormholes, the notion of the phantom energy was used in a more extended sense than in cosmology, where the phantom energy is considered a homogeneously distributed fluid. Specifically, for some static wormhole geometries the phantom matter was considered as an inhomogeneous and anisotropic fluid, with radial and lateral pressures satisfying the relations $p_{r}/\\rho<-1$ and $p_{_l} \

  6. Confronting Phantom Dark Energy with Observations

    CERN Document Server

    Wang, Pao-Yu; Chen, Pisin

    2012-01-01

    We confront two types of phantom dark energy potential with observational data. The models we consider are the power-law potential, $V\\propto {\\phi}^{\\mu}$, and the exponential potential, $V\\propto \\exp({\\lambda}{\\phi}/{M_P})$. We fit the models to the latest observations from SN-Ia, CMB and BAO, and obtain tight constraints on parameter spaces. Furthermore, we apply the goodness-of-fit and the information criteria to compare the fitting results from phantom models with that from the cosmological constant and the quintessence models presented in our previous work. The results show that the cosmological constant is statistically most preferred, while the phantom dark energy fits slightly better than the quintessence does.

  7. Cosmological perturbations in transient phantom inflation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Richarte, Martin G. [Universidade Federal do Parana, Departamento de Fisica, Caixa Postal 19044, Curitiba (Brazil); Universidad de Buenos Aires, Ciudad Universitaria 1428, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Kremer, Gilberto M. [Universidade Federal do Parana, Departamento de Fisica, Caixa Postal 19044, Curitiba (Brazil)

    2017-01-15

    We present a model of inflation where the inflaton is accommodated as a phantom field which exhibits an initial transient pole behavior and then decays into a quintessence field which is responsible for a radiation era. We must stress that the present unified model only deals with a single field and that the transition between the two eras is achieved in a smooth way, so the model does not suffer from the eternal inflation issue. We explore the conditions for the crossing of the phantom divide line within the inflationary era along with the structural stability of several critical points. We study the behavior of the phantom field within the slow-climb approximation along with the necessary conditions to have sufficient inflation. We also examine the model at the level of classical perturbations within the Newtonian gauge and determine the behavior of the gravitational potential, contrast density and perturbed field near the inflation stage and the subsequent radiation era. (orig.)

  8. Photoacoustic investigation of a neonatal skull phantom

    Science.gov (United States)

    Volinski, Bridget; Hariri, Ali; Fatima, Afreen; Xu, Qiuyun; Nasiriavanaki, Mohammadreza

    2017-03-01

    There is a need for continued research into the diagnosis, prevention and cure of neonatal brain disease and disorders. These disorders lead to fatalities and developmental disorders in infants. Non-invasive imaging techniques are being researched for this purpose. However, the availability of neonatal skull samples for this work is very low. A phantom can be used to simulate the neonatal skull and brain to improve imaging techniques. This study selects a phantom of polyurethane and titanium dioxide and proves its value as a replacement for neonatal skull in research. The methods used for this proof are validation of choice against the literature, transmissivity and acoustic experimentation compared to existing literature, and finally photoacoustic evaluation of the final choice to show its usefulness as a neonatal skull phantom.

  9. Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

    Energy Technology Data Exchange (ETDEWEB)

    Yusof, Mohd Fahmi Mohd, E-mail: mfahmi@usm.my; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz [School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Bauk, Sabar [School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia); Hashim, Rokiah [School of Industrial Technologies, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-04-29

    Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest value of CT number to water substitute at 80 and 120 kVp CT energies with χ{sup 2} value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ{sup 2} value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies.

  10. Development of a patient-specific two-compartment anthropomorphic breast phantom

    Science.gov (United States)

    Prionas, Nicolas D.; Burkett, George W.; McKenney, Sarah E.; Chen, Lin; Stern, Robin L.; Boone, John M.

    2012-07-01

    The purpose of this paper is to develop a technique for the construction of a two-compartment anthropomorphic breast phantom specific to an individual patient's pendant breast anatomy. Three-dimensional breast images were acquired on a prototype dedicated breast computed tomography (bCT) scanner as part of an ongoing IRB-approved clinical trial of bCT. The images from the breast of a patient were segmented into adipose and glandular tissue regions and divided into 1.59 mm thick breast sections to correspond to the thickness of polyethylene stock. A computer-controlled water-jet cutting machine was used to cut the outer breast edge and the internal regions corresponding to glandular tissue from the polyethylene. The stack of polyethylene breast segments was encased in a thermoplastic ‘skin’ and filled with water. Water-filled spaces modeled glandular tissue structures and the surrounding polyethylene modeled the adipose tissue compartment. Utility of the phantom was demonstrated by inserting 200 µm microcalcifications as well as by measuring point dose deposition during bCT scanning. Affine registration of the original patient images with bCT images of the phantom showed similar tissue distribution. Linear profiles through the registered images demonstrated a mean coefficient of determination (r2) between grayscale profiles of 0.881. The exponent of the power law describing the anatomical noise power spectrum was identical in the coronal images of the patient's breast and the phantom. Microcalcifications were visualized in the phantom at bCT scanning. The real-time air kerma rate was measured during bCT scanning and fluctuated with breast anatomy. On average, point dose deposition was 7.1% greater than the mean glandular dose. A technique to generate a two-compartment anthropomorphic breast phantom from bCT images has been demonstrated. The phantom is the first, to our knowledge, to accurately model the uncompressed pendant breast and the glandular tissue

  11. Standard operating procedure to prepare agar phantoms

    Science.gov (United States)

    Souza, R. M.; Santos, T. Q.; Oliveira, D. P.; Souza, R. M.; Alvarenga, A. V.; Costa-Felix, R. P. B.

    2016-07-01

    Agar phantoms are widely used as soft tissue mimics and some preparation techniques are described in the literature. There are also standards that describe the recipe of a soft tissue mimicking material (TMM). However some details of manufacture process are not clearly defined. The standardization of the phantom's preparation can produce a metrological impact on the results of the acoustic properties measured. In this direction, this paper presents a standard operating procedure (SOP) to prepare the agar TMM described on the IEC 60601-237.

  12. [Phantom limb pain. Psychological treatment strategies].

    Science.gov (United States)

    Diers, M; Flor, H

    2013-04-01

    Similar to other pain syndromes phantom limb pain is characterized by learning and memory processes that maintain the pain and increase maladaptive plastic changes of the brain: therefore, psychological interventions that change maladaptive memory processes are useful. In addition to traditional psychological interventions, such as pain management training and biofeedback, more recent developments that involve sensory discrimination training, mirror treatment, graded motor imagery, prosthesis training and training in virtual reality are interesting. These interventions not only reduce phantom limb pain but also reverse the associated maladaptive brain changes.

  13. Structured movement representations of a phantom limb associated with phantom limb pain.

    Science.gov (United States)

    Osumi, Michihiro; Sumitani, Masahiko; Wake, Naoki; Sano, Yuko; Ichinose, Akimichi; Kumagaya, Shin-Ichiro; Kuniyoshi, Yasuo; Morioka, Shu

    2015-09-25

    The relation between phantom limb pain (PLP) and the movement representation of a phantom limb remains controversial in several areas of neurorehabilitation, although there are a few studies in which the representation of phantom limb movement was precisely evaluated. We evaluated the structured movement representation of a phantom limb objectively using a bimanual circle-line coordination task. We then investigated the relation between PLP and the structured movement representation. Nine patients with a brachial plexus avulsion injury were enrolled who perceived a phantom limb and had neuropathic pain. While blindfolded, the participants repeatedly drew vertical lines using the intact hand and intended to draw circles using the phantom limb simultaneously. "Drawing of circles" by the phantom limb resulted in an oval transfiguration of the vertical lines ("bimanual coupling" effect). We used an arbitrary ovalization index (OI) to quantify the oval transfiguration. When the OI neared 100%, the trajectory changed toward becoming more circular. A significant negative correlation was observed between the intensity of PLP and the OI (r=-0.66, pphantom limb are necessary for alleviating PLP.

  14. Annihilation photon acollinearity in PET: volunteer and phantom FDG studies.

    Science.gov (United States)

    Shibuya, Kengo; Yoshida, Eiji; Nishikido, Fumihiko; Suzuki, Toshikazu; Tsuda, Tomoaki; Inadama, Naoko; Yamaya, Taiga; Murayama, Hideo

    2007-09-07

    Annihilation photon acollinearity is a fundamental but little investigated problem in positron emission tomography (PET). In this paper, the cause of the angular deviation from 180.00 degrees is described as well as how to evaluate it under conditions of a spatially distributed radiation source and a limited acquisition time for the human body. A relationship between the shape of the photopeak spectrum and the angular distribution is formulated using conservation laws of momentum and energy over the pair annihilation. Then the formula is used to evaluate the acollinearity for a pool phantom and the human body with FDG injected. The angular distribution for the pool phantom agrees well with that for pure water which had been directly measured by Colombino et al in 1965 (Nuovo Cimento 38 707-23), and also with that for the human body determined in this study. Pure water can be considered as a good approximation of the human body regarding the angular deviation. The blurring coefficient to be multiplied by the ring diameter in calculations of the PET spatial resolution is experimentally determined for the first time as 0.00243 +/- 0.00014; this is 10% larger than the value widely used by investigators.

  15. 33 CFR 117.925 - Cooper River.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Cooper River. 117.925 Section 117.925 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements South Carolina § 117.925 Cooper River. The draw of the...

  16. 33 CFR 117.713 - Cooper River.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Cooper River. 117.713 Section 117.713 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements New Jersey § 117.713 Cooper River. (a) The drawspans for...

  17. The co-production of a "relevant" expertise - administrative and scientific cooperation in the French water policies elaboration and implementation

    Science.gov (United States)

    Deroubaix, J. F.

    2007-10-01

    This paper aims at understanding the social and political uses of the principle of integrated management and its possible impacts on the elaboration and implementation processes of public policies in the French water management field. The academic and political innovations developed by scientists and agents of the administration these last 25 years are analysed, using some of the theoretical tools developed by the science studies and public policy analysis. We first focus on the construction of intellectual public policy communities such as the GIP Hydro systems, at the origin of large interdisciplinary research programs in the 1990s. A common cognitive framework is clearly built during this period on the good governance of the aquatic ecosystems and on the corresponding needs and practices of research. The second part of the paper focuses on the possibilities to build political communities and more or less integrated expertises in the decision making processes concerning various issues related to water management. Eutrophication and its inscription on the French political agenda is a very significant case for analysing the difficulty to build such a political community. On the contrary, when there is an opportunity for policy evaluation, which was the case concerning the management of wetlands in France or the implementation of compulsory flows on the French rivers, these communities can emerge. However, the type of integrated expertise and management proposed in these cases of policy evaluations much depends on their methodological choices.

  18. SU-E-T-89: Comprehensive Quality Assurance Phantom for the Small Animal Radiation Research Platform

    Energy Technology Data Exchange (ETDEWEB)

    Jermoumi, M; Ngwa, W [University of Massachusetts Lowell, MA (United States); Dana-Farber Cancer Institute, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States); Korideck, H; Zygmanski, P; Berbeco, R; Makrigiorgos, G; Cormack, R [Dana-Farber Cancer Institute, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States)

    2014-06-01

    Purpose: Use of Small Animal Radiation Research Platform (SARRP) systems for conducting state-of-the-art image guided radiotherapy (IGRT) research on small animals has become more common over the past years. The purpose of this work is to develop and test the suitability and performance of a comprehensive quality assurance (QA) phantom for the SARRP. Methods: A QA phantom was developed for carrying out daily, monthly and annual QA tasks including imaging, dosimetry and treatment planning system (TPS) performance evaluation of the SARRP. The QA phantom consists of nine (60×60×5 mm3) KV-energy tissue equivalent solid water slabs that can be employed for annual dosimetry QA with film. Three of the top slabs are replaceable with ones incorporating Mosfets or OSLDs arranged in a quincunx pattern, or a slab drilled to accommodate an ion chamber insert. These top slabs are designed to facilitate routine daily and monthly QA tasks such as output constancy, isocenter congruency test, treatment planning system (TPS) QA, etc. One slab is designed with inserts for image QA. A prototype of the phantom was applied to test the performance of the imaging, planning and treatment delivery systems. Results: Output constancy test results showed daily variations within 3%. For isocenter congruency test, the phantom could be used to detect 0.3 mm deviations of the CBCT isocenter from the radiation isocenter. Using the Mosfet in phantom as target, the difference between TPS calculations and measurements was within 5%. Image-quality parameters could also be assessed in terms of geometric accuracy, CT number accuracy, linearity, noise and image uniformity, etc. Conclusion: The developed phantom can be employed as a simple tool for comprehensive performance evaluation of the SARRP. The study provides a reference for development of a comprehensive quality assurance program for the SARRP, with proposed tolerances and frequency of required tests.

  19. Phantom breast sensations are frequent after mastectomy

    DEFF Research Database (Denmark)

    Hansen, Dorthe Marie Helbo; Kehlet, Henrik; Gärtner, Rune

    2011-01-01

    Phantom breast sensation (PBS) following mastectomy has been recognized for many years. PBS is a feeling that the removed breast is still there. The reported prevalence and risk factors have not been established in large well-defined patient series. The purpose of this study was to examine...

  20. Note on the Schwarzschild-phantom wormhole

    CERN Document Server

    Lukmanova, Regina; Izmailov, Ramil; Yanbekov, Almir; Karimov, Ramis; Potapov, Alexander A

    2016-01-01

    Recently, it has been shown by Lobo, Parsaei and Riazi (LPR) that phantom energy with $\\omega =p_{r}/\\rho <-1$ could support phantom wormholes. Several classes of such solutions have been derived by them. While the inner spacetime is represented by asymptotically flat phantom wormhole that have repulsive gravity, it is most likely to be unstable to perturbations. Hence, we consider a situation, where a phantom wormhole is somehow trapped inside a Schwarzschild sphere across a thin shell. Applying the method developed by Garcia, Lobo and Visser (GLV), we shall exemplify that the shell can possess zones of stability depending on certain constraints. It turns out that zones corresponding to "force" constraint are more restrictive than those from the "mass" constraint. We shall also enumerate the interior energy content by using the gravitational energy integral proposed by Lynden-Bell, Katz and Bi% \\v{c}\\'ak. It turns out that, even though the interior mass is positive, the integral implies repulsive energy. ...

  1. Phantom breast sensations are frequent after mastectomy

    DEFF Research Database (Denmark)

    Hansen, Dorthe Marie Helbo; Kehlet, Henrik; Gærtner, Rune

    2011-01-01

    Phantom breast sensation (PBS) following mastectomy has been recognized for many years. PBS is a feeling that the removed breast is still there. The reported prevalence and risk factors have not been established in large well-defined patient series. The purpose of this study was to examine...... the prevalence of PBS following mastectomy and associated risk factors....

  2. A precise CT phantom alignment procedure.

    Science.gov (United States)

    Schneiders, N J; Bushong, S C

    1980-01-01

    Two of the AAPM CT performance phantom inserts require precise alignment. We present a method for aligning an insert which makes use of the partial volume effect. We demonstrate that the procedure is sensitive to tilts of less than one degree and, using the slice thickness insert, allows reproducible positioning.

  3. Evaluation of HCMM satellite data for estuarine tidal circulation patterns and thermal inertia soil moisture measurements. [Delaware Bay, Cooper River, and the Potomac River estuaries; Luverne, Minnesota, soil moisture, and water temperature of Lake Anna, Virginia

    Science.gov (United States)

    Wiesnet, D. R.; Mcginnis, D. F., Jr. (Principal Investigator); Matson, M.; Pritchard, J. A.

    1981-01-01

    Digital thermal maps of the Cooper River (SC) and the Potomac River estuaries were prepared from heat capacity mapping radiometer (HCMR) tapes. Tidal phases were correctly interpreted and verified. Synoptic surface circulation patterns were charted by location thermal fronts and water mass boundaries within the estuaries. Thermal anomalies were detected adjacent of a conventional power plant on the Potomac. Under optimum conditions, estuaries as small as the Cooper River can be monitored for generalized thermal/tidal circulation patterns by the HCMM-type IR sensors. The HCMM thermal inertia approach to estimating soil moisture at the Luverne (MN) test site was found to be unsatisfactory as a NESS operational satellite technique because of cloud cover interference. Thermal-IR data show similar structure of the Baltimore and Washington heat islands when compared to NOAA AVHRR thermal-IR data. Thermal anomalies from the warm water discharge water of a nuclear power plant were mapped in Lake Anna, Virginia.

  4. Research on Inter-governmental Cooperative Mechanism in Trans-boundary Water Environment Conservation%跨界水环境保护中的政府间合作机制研究

    Institute of Scientific and Technical Information of China (English)

    李培; 张风春; 张晓岚

    2013-01-01

    Development of an effective inter-governmental horizontal cooperative mechanism is an important solution to improve the trans-boundary water environment management in China.Much efforts has been performed and desired results have been achieved in the international trans-boundary water co-management,cooperation among different ministries in China,trans-boundary water cooperation among local governments,and departmental cooperation inside one government.At present,the horizontal cooperation among governments is carried out through the agreements,planning,joint action,and joint conference,and these methods generally involve different departments of the government.The content of the cooperation includes the law,policy,institution,and information sharing,monitoring and assessment.However,due to the existing problems in the law,cooperative mechanism,and technical support,the inter-governmental horizontal cooperative mechanism did not act significantly effectively in China and the contamination in trans-boundary surface water is still severe.Therefore,several countermeasures were proposed in this paper,including the improvement of system and structure of the cooperative mechanism,strengthening of the core content of cooperative mechanism,enrichment of realization solutions of cooperative mechanism,and improvement of the secure conditions of cooperative mechanism.%建立有效的政府间横向合作机制是完善我国跨界水环境管理的重要途径.我国已经在国际跨界水域共管、国家层面上的部际合作、地方政府间的跨界水域合作以及地方政府内部部门间的合作等方面做了大量的尝试并取得了理想的效果.目前,我国各类政府间横向合作主要是通过协议、计划、联合行动、联席会议等方式开展,而且一般都有政府部门的参与.合作的内容从法律、政策、机构到信息共享与监测和评价,非常广泛.由于尚存在着法律、协调机制、科技支撑等方面的

  5. Atypical supernumerary phantom limb and phantom limb pain in two patients with pontine hemorrhage.

    Science.gov (United States)

    Yoo, Seung Don; Kim, Dong Hwan; Jeong, Yong Seol; Chon, Jinmann; Bark, Jihea

    2011-06-01

    Phantom limbs are usually observed after amputation of extremities. In patients after a stroke, a similar but rarely occurring phenomenon consisting of the patient experiencing the presence of an additional limb has been described. This phenomenon, generally called supernumerary phantom limb (SPL), may be caused by lesions in the right or left cerebral hemisphere, but has been predominantly reported in patients who have had a right hemispheric stroke. We report two cases of atypical SPL and phantom limb pain (PLP) after pontine hemorrhage. The patients were treated conservatively and their symptoms lasted more than 1 month. This is the first report of SPLs after left pontine hemorrhage, and phantom perception and pain lasted longer than those in previously observed cases. Our results indicate that SPL may be more common than reported; therefore, thorough examinations are essential for the care of stroke patients.

  6. Acoustic characterization of polyvinyl chloride and self-healing silicone as phantom materials

    Science.gov (United States)

    Ceh, Dennis; Peters, Terry M.; Chen, Elvis C. S.

    2015-03-01

    Phantoms are physical constructs used in procedure planning, training, medical imaging research, and machine calibration. Depending on the application, the material a phantom is made out of is very important. With ultrasound imaging, phantom materials used need to have similar acoustic properties, specifically speed of sound and attenuation, as a specified tissue. Phantoms used with needle insertion require a material with a similar tensile strength as tissue and, if possible, the ability to self heal increasing its overall lifespan. Soft polyvinyl chloride (PVC) and silicone were tested as possible needle insertion phantom materials. Acoustic characteristics were determined using a time of flight technique, where a pulse was passed through a sample contained in a water bath. The speed of sound and attenuation were both determined manually and through spectral analysis. Soft PVC was determined to have a speed of sound of approximately 1395 m/s and attenuation of 0.441 dB/cm (at 1 MHz). For the silicone mixture, the respective speed of sound values was within a range of 964.7 m/s and 1250.0 m/s with an attenuation of 0.547 dB/cm (at 1 MHz).

  7. Tissue equivalence of some phantom materials for proton beams

    CERN Document Server

    Vasiliev, V N; Riazantsev, O B; Khaybullin, V G; Samarin, S I; Uglov, A S

    2010-01-01

    Tissue and water equivalence of some phantom materials originally developed for conventional radiation therapy was investigated on the ITEP medical proton beam facility. The proton CSDA range in three variants of Plastic Water, lung, adipose, muscle and compact bone substitute materials (CIRS Inc., USA) was measured by a silicon diode as well as the residual proton range in liquid water after passing a slab of each material under investigation. In addition, the proton range in five materials of known elemental composition was calculated by Monte Carlo technique. The obtained results were compared with reference data from ICRU report 49 for respective biological tissues and water. A total uncertainty of the proton range ratios was estimated to be from 0.9 to 1.5% (1SD). Within these uncertainties, Plastic Water, Plastic Water LR, Plastic Water DT, muscle and compact bone demonstrated a good agreement with the reference data. The range in adipose and lung substitutes is a few percents lower than that in the res...

  8. Calculation of dose in homogeneous phantoms for partially attenuated photon beams

    Energy Technology Data Exchange (ETDEWEB)

    El-Khatib, E.; Podgorsak, E.B.; Pla, C.

    1988-03-01

    Measured and calculated dose distributions under attenuators, which are of smaller cross-sectional dimensions than the radiation field, are presented. The study was performed on a 4-MV linac at a source--surface distance of 120 cm on the beam central axis in a water phantom for several thicknesses and cross sections of lead attenuators. Dose correction factors, which are used to multiply the open beam data to get dose distributions under partial attenuators, depend strongly on attenuator parameters and on depths in phantom. A method to calculate dose correction factors for any combination of attenuator parameters and any phantom depth is presented. The calculated dose distributions under partial attenuators agree well with measured data, which indicates that the method can be applied in clinical situations.

  9. Calculation of dose profiles in homogeneous phantoms for irregular, partially attenuated, photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Pla, C.; Podgorsak, E.B.; El-Khatib, E.

    1988-07-01

    Measured and calculated dose profiles under partial attenuators which cover only part of the radiation beam are presented. The study was performed for x-ray beams generated with a 4-MV linear accelerator at a source--surface distance of 120 cm in a water phantom for lead attenuators of arbitrary shape but constant thickness. Dose correction factors, which are used to multiply the open beam data to predict doses under partial attenuators, depend strongly on attenuator parameters, such as its thickness, lateral dimensions, and distance from phantom or patient surface, in addition to depending on depths in the phantom. The dose correction factors are calculated with Clarkson sector integration techniques, and the results, in spite of the simplifying assumptions used in the algorithm, generally agree with measured data to within 3%. The calculational method therefore may be applied to general clinical situations in which partial attenuators are used.

  10. Phantom limb pain: a case of maladaptive CNS plasticity?

    DEFF Research Database (Denmark)

    Flor, Herta; Nikolajsen, Lone; Jensen, Troels Staehelin

    2006-01-01

    Phantom pain refers to pain in a body part that has been amputated or deafferented. It has often been viewed as a type of mental disorder or has been assumed to stem from pathological alterations in the region of the amputation stump. In the past decade, evidence has accumulated that phantom pain...... studies and derive suggestions for innovative interventions aimed at alleviating phantom pain....

  11. Cooperative effects in CdSe/ZnS-PEGOH quantum dot luminescence quenching by a water soluble porphyrin

    Energy Technology Data Exchange (ETDEWEB)

    Borissevitch, I.E., E-mail: iourib@ffclrp.usp.br [Departamento de Fisica, Faculdade de Filosofia Ciencia e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, SP (Brazil); Parra, G.G. [Departamento de Fisica, Faculdade de Filosofia Ciencia e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes 3900, Ribeirao Preto, SP (Brazil); Zagidullin, V.E.; Lukashev, E.P.; Knox, P.P.; Paschenko, V.Z.; Rubin, A.B. [Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, Vorobyovy Gory, 119991 Moscow (Russian Federation)

    2013-02-15

    In this work we report on the study of the interaction of CdSe/ZnS-PEGOH 570 Quantum Dot (QD) with negatively charged meso-tetrakis(p-sulfonato-phenyl)porphyrin (TPPS{sub 4}) using optical absorption and fluorescence spectroscopies accompanied with time resolved 'single photon counting' and dynamic and resonance light scattering techniques. In the steady-state experiments the QD luminescence quenching by TPPS{sub 4} was well approximated by a square law. In the time-resolved experiments we observed a typical multi-exponential luminescence decay curve, successfully fitted by a bi-exponential approximation. At QD interaction with porphyrin the time quenching of both components was described by a linear Stern-Volmer dependence. The discrepancy between Stern-Volmer dependences in the steady-state and time resolved experiments may be due to formation of mixed m(TPPS{sub 4})+n(QD) complexes, in which one TPPS{sub 4} molecule can quench several excited QDs. This idea is in accordance with the dynamic and resonance light scattering data, which demonstrate an increase of the scattering particle size at the TPPS{sub 4} addition to QD solutions. - Highlights: Black-Right-Pointing-Pointer Quantum Dot luminescence quenching by TPPS porphyrin was studied in water solutions. Black-Right-Pointing-Pointer The size of particles in QD solutions possessed increase at the TPPS4 addition. Black-Right-Pointing-Pointer Quenching of the QD luminescence by TPPS4 is realized in contact QD-porphyrin complexes. Black-Right-Pointing-Pointer The formation of mixed quantum dot-porphyrin aggregates takes place.

  12. SU-E-I-22: Dependence On Calibration Phantom and Field Area of the Conversion Factor Used to Calculate Skin Dose During Neuro-Interventional Fluoroscopic Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Rana, V K; Vijayan, S [Physiology and Biophysics, Toshiba Stroke and Vascular Research Center, University at Buffalo (State University of New York), Buffalo, NY (United States); Rudin, S R; Bednarek, D R [Department of Radiology, Physiology and Biophysics, Toshiba Stroke and Vascular Research Center, University at Buffalo (State University of New York), Buffalo, NY (United States)

    2014-06-01

    Purpose: To determine the appropriate calibration factor to use when calculating skin dose with our real-time dose-tracking system (DTS) during neuro-interventional fluoroscopic procedures by evaluating the difference in backscatter from different phantoms and as a function of entrance-skin field area. Methods: We developed a dose-tracking system to calculate and graphically display the cumulative skin-dose distribution in real time. To calibrate the DTS for neuro-interventional procedures, a phantom is needed that closely approximates the scattering properties of the head. We compared the x-ray backscatter from eight phantoms: 20-cm-thick solid water, 16-cm diameter water-filled container, 16-cm CTDI phantom, modified-ANSI head phantom, 20-cm-thick PMMA, Kyoto-Kagaku PBU- 50 head, Phantom-Labs SK-150 head, and RSD RS-240T head. The phantoms were placed on the patient table with the entrance surface at 15 cm tube-side from the isocenter of a Toshiba Infinix C-arm, and the entrance-skin exposure was measured with a calibrated 6-cc PTW ionization chamber. The measurement included primary radiation, backscatter from the phantom and forward scatter from the table and pad. The variation in entrance-skin exposure was also measured as a function of the skin-entrance area for a 30x30 cm by 20-cm-thick PMMA phantom and the SK-150 head phantom using four different added beam filters. Results: The entranceskin exposure values measured for eight different phantoms differed by up to 12%, while the ratio of entrance exposure of all phantoms relative to solid water showed less than 3% variation with kVp. The change in entrance-skin exposure with entrance-skin area was found to differ for the SK-150 head compared to the 20-cm PMMA phantom and the variation with field area was dependent on the added beam filtration. Conclusion: To accurately calculate skin dose for neuro-interventional procedures with the DTS, the phantom for calibration should be carefully chosen since different

  13. Cooperative protein structural dynamics of homodimeric hemoglobin linked to water cluster at subunit interface revealed by time-resolved X-ray solution scattering

    Directory of Open Access Journals (Sweden)

    Jong Goo Kim

    2016-03-01

    Full Text Available Homodimeric hemoglobin (HbI consisting of two subunits is a good model system for investigating the allosteric structural transition as it exhibits cooperativity in ligand binding. In this work, as an effort to extend our previous study on wild-type and F97Y mutant HbI, we investigate structural dynamics of a mutant HbI in solution to examine the role of well-organized interfacial water cluster, which has been known to mediate intersubunit communication in HbI. In the T72V mutant of HbI, the interfacial water cluster in the T state is perturbed due to the lack of Thr72, resulting in two less interfacial water molecules than in wild-type HbI. By performing picosecond time-resolved X-ray solution scattering experiment and kinetic analysis on the T72V mutant, we identify three structurally distinct intermediates (I1, I2, and I3 and show that the kinetics of the T72V mutant are well described by the same kinetic model used for wild-type and F97Y HbI, which involves biphasic kinetics, geminate recombination, and bimolecular CO recombination. The optimized kinetic model shows that the R-T transition and bimolecular CO recombination are faster in the T72V mutant than in the wild type. From structural analysis using species-associated difference scattering curves for the intermediates, we find that the T-like deoxy I3 intermediate in solution has a different structure from deoxy HbI in crystal. In addition, we extract detailed structural parameters of the intermediates such as E-F distance, intersubunit rotation angle, and heme-heme distance. By comparing the structures of protein intermediates in wild-type HbI and the T72V mutant, we reveal how the perturbation in the interfacial water cluster affects the kinetics and structures of reaction intermediates of HbI.

  14. Motor control over the phantom limb in above-elbow amputees and its relationship with phantom limb pain.

    Science.gov (United States)

    Gagné, M; Reilly, K T; Hétu, S; Mercier, C

    2009-08-04

    Recent evidence shows that the primary motor cortex continues to send motor commands when amputees execute phantom movements. These commands are retargeted toward the remaining stump muscles as a result of motor system reorganization. As amputation-induced reorganization in the primary motor cortex has been associated with phantom limb pain we hypothesized that the motor control of the phantom limb would differ between amputees with and without phantom limb pain. Eight above-elbow amputees with or without pain were included in the study. They were asked to produce cyclic movements with their phantom limb (hand, wrist, and elbow movements) while simultaneously reproducing the same movement with the intact limb. The time needed to complete a movement cycle and its amplitude were derived from the kinematics of the intact limb. Electromyographic (EMG) activity from different stump muscles and from the homologous muscles on the intact side was recorded. Different EMG patterns were recorded in the stump muscles depending on the movement produced, showing that different phantom movements are associated with distinct motor commands. Phantom limb pain was associated with some aspects of phantom limb motor control. The time needed to complete a full cycle of a phantom movement was systematically shorter in subjects without phantom limb pain. Also, the amount of EMG modulation recorded in a stump muscle during a phantom hand movement was positively correlated with the intensity of phantom limb pain. Since phantom hand movement-related EMG patterns in above-elbow stump muscles can be considered as a marker of motor system reorganization, this result indirectly supports the hypothesis that amputation-induced plasticity is associated with phantom limb pain severity. The discordance between the (amputated) hand motor command and the feedback from above-elbow muscles might partially explain why subjects exhibiting large EMG modulation during phantom hand movement have more phantom

  15. In-phantom spectra and dose distributions from a high-energy neutron therapy beam

    CERN Document Server

    Benck, S; Denis, J M; Meulders, J P; Nath, R; Pitcher, E J

    2002-01-01

    In radiotherapy with external beams, healthy tissues surrounding the target volumes are inevitably irradiated. In the case of neutron therapy, the estimation of dose to the organs surrounding the target volume is particularly challenging, because of the varying contributions from primary and secondary neutrons and photons of different energies. The neutron doses to tissues surrounding the target volume at the Louvain-la-Neuve (LLN) facility were investigated in this work. At LLN, primary neutrons have a broad spectrum with a mean energy of about 30 MeV. The transport of a 10x10 cm sup 2 beam through a water phantom was simulated by means of the Monte Carlo code MCNPX. Distributions of energy-differential values of neutron fluence, kerma and kerma equivalent were estimated at different locations in a water phantom. The evolution of neutron dose and dose equivalent inside the phantom was deduced. Measurements of absorbed dose and of dose equivalent were then carried out in a water phantom using an ionization ch...

  16. Nonlinear elastic behavior of phantom materials for elastography

    Energy Technology Data Exchange (ETDEWEB)

    Pavan, Theo Z; Madsen, Ernest L; Frank, Gary R; Hall, Timothy J [Medical Physics Department, University of Wisconsin, Room 1005, Wisconsin Institutes for Medical Research, 1111 Highland Avenue, Madison, WI 53705 (United States); Adilton O Carneiro, Antonio, E-mail: tjhall@wisc.ed [Departamento de Fisica e Matematica, FFCLRP, Universidade de Sao Paulo, Av. Bandeirantes, 3900, Monte Alegre, Ribeirao Preto, Sao Paulo (Brazil)

    2010-05-07

    The development of phantom materials for elasticity imaging is reported in this paper. These materials were specifically designed to provide nonlinear stress/strain relationship that can be controlled independently of the small strain shear modulus of the material. The materials are mixtures of agar and gelatin gels. Oil droplet dispersions in these materials provide further control of the small strain shear modulus and the nonlinear parameter of the material. Since these materials are mostly water, they are assumed to be incompressible under typical experimental conditions in elasticity imaging. The Veronda-Westman model for strain energy density provided a good fit to all materials used in this study. Materials with a constant gelatin concentration (3.0% dry weight) but varying agar concentration (0.6-2.8% dry weight) demonstrated the same power law relationship between elastic modulus and agar concentration found for pure agar (1.89 {+-} 0.02), consistent with percolation theory, and provided a consistent nonlinearity parameter of 4.5 {+-} 0.3. The insights provided by this study will form the basis for stable elastography phantoms with stiffness and nonlinear stress/strain relationships in the background that differ from those in the target.

  17. Non-degradable triazine substrates of atrazine and cyanuric acid hydrothermally and in supercritical water under the UV-illuminated photocatalytic cooperation.

    Science.gov (United States)

    Horikoshi, Satoshi; Hidaka, Hisao

    2003-04-01

    Strong oxidation by titanium dioxide photocatalysis can occur by photodegradation of organic contaminants in air and water. Some endocrine disruptors such as 2,4-dichlorophenoxy acetic acid (;;; ), 2,4-dichlorophenol (;;; ), nonylphenol (; ), bisphenol A (), diethyl phthalate (; ), etc. which can be neither biodegraded by bacteria nor degraded thermally can be degraded by TiO(2) photocatalytic treatment. However, incomplete photomineralization partly occurred, when TiO(2) photocatalytic degradation is employed for the treatment of certain endocrine disruptors. For example, no atrazine pesticide having triazine skeleton can be completely mineralized even by a photocatalytic procedure; the photodegradation of atrazine ultimately stops at the intermediate step of cyanuric acid, which cannot be photodegraded even after long illumination times (). In this study, the decomposition of atrazine and cyanuric acid was carried out with a device combining photocatalytic degradation in supercritical water (scH(2)O) or hydrothermal water (hyH(2)O). Atrazine and cyanuric acid can be degraded by the cooperation of either scH(2)O or hyH(2)O and UV illuminated TiO(2)-photocatalytic dispersed system under the fixed pressure of 23 MPa at 623 K or 683 K in a 120-ml Hastelloy batch reactor. The photocatalytic degradation method under high temperature and pressure has found appropriate for the photocatalytic oxidation of acetic acid and 2-chlorobiphenyl under continuous flow conditions at 160 degrees C and 20 atm (). In addition, the wet peroxide oxidation of PCBs by high temperature and pressure has been reported (). The main aims of this research are following. (i): the degradation of atrazine and cyanuric acid within the scH(2)O or hyH(2)O, (ii) the decomposition of atrazine and cyanuric acid catalyzed by TiO(2) particles under scH(2)O or hyH(2)O, and the synergistic effect for several reactions with TiO(2) and scH(2)O or hyH(2)O, and (iii) the mineralization yield of nitrogen and

  18. Phantom cosmology and Boltzmann brains problem

    CERN Document Server

    Astashenok, Artyom V; Yurov, Valerian V

    2013-01-01

    We consider the well-known Boltzmann brains problem in frames of simple phantom energy models with little rip, big rip and big freeze singularity. It is showed that these models (i) satisfy to observational data and (ii) may be free from Boltzmann brains problem. The human observers in phantom models can exist only in during for a certain period $t

  19. Photoacoustic microscopy of bilirubin in tissue phantoms

    Science.gov (United States)

    Zhou, Yong; Zhang, Chi; Yao, Da-Kang; Wang, Lihong V.

    2012-12-01

    Determining both bilirubin's concentration and its spatial distribution are important in disease diagnosis. Here, for the first time, we applied quantitative multiwavelength photoacoustic microscopy (PAM) to detect bilirubin concentration and distribution simultaneously. By measuring tissue-mimicking phantoms with different bilirubin concentrations, we showed that the root-mean-square error of prediction has reached 0.52 and 0.83 mg/dL for pure bilirubin and for blood-mixed bilirubin detection (with 100% oxygen saturation), respectively. We further demonstrated the capability of the PAM system to image bilirubin distribution both with and without blood. Finally, by underlaying bilirubin phantoms with mouse skins, we showed that bilirubin can be imaged with consistent accuracy down to >400 μm in depth. Our results show that PAM has potential for noninvasive bilirubin monitoring in vivo, as well as for further clinical applications.

  20. Cosmological perturbations on the phantom brane

    Science.gov (United States)

    Bag, Satadru; Viznyuk, Alexander; Shtanov, Yuri; Sahni, Varun

    2016-07-01

    We obtain a closed system of equations for scalar perturbations in a multi-component braneworld. Our braneworld possesses a phantom-like equation of state at late times, weff Consequently, the quasi-static approximation of Koyama and Maartens provides a good fit to the exact results during the matter-dominated epoch. We find that the late-time growth of density perturbations on the brane proceeds at a faster rate than in ΛCDM. Additionally, the gravitational potentials Φ and Ψ evolve differently on the brane than in ΛCDM, for which Φ = Ψ. On the brane, by contrast, the ratio Φ/Ψ exceeds unity during the late matter-dominated epoch (z lesssim 50). These features emerge as smoking gun tests of phantom brane cosmology and allow predictions of this scenario to be tested against observations of galaxy clustering and large-scale structure.

  1. Toxicology Analysis of Tissue-Mimicking Phantom Made From Gelatin

    Science.gov (United States)

    Dolbashid, A. S.; Hamzah, N.; Zaman, W. S. W. K.; Mokhtar, M. S.

    2017-06-01

    Skin phantom mimics the biological skin tissues as it have the ability to respond to changes in its environment. The development of tissue-mimicking phantom could contributes towards the reduce usage of animal in cosmetics and pharmacokinetics. In this study, the skin phantoms made from gelatin were tested with four different commonly available cosmetic products to determine the toxicity of each substance. The four substances used were; mercury-based whitening face cream, carcinogenic liquid make-up foundation, paraben-based acne cleanser, and organic lip balm. Toxicity test were performed on all of the phantoms. For toxicity testing, topographical and electrophysiological changes of the phantoms were evaluated. The ability of each respective phantom to react with mild toxic substances and its electrical resistance were analysed in to determine the toxicity of all the phantom models. Four-electrode method along with custom made electrical impedance analyser was used to differentiate electrical resistance between intoxicated phantom and non-intoxicated phantom in this study. Electrical resistance values obtained from the phantom models were significantly higher than the control group. The result obtained suggests the phantom as a promising candidate to be used as alternative for toxicology testing in the future.

  2. Pipe Phantoms With Applications in Molecular Imaging and System Characterization.

    Science.gov (United States)

    Wang, Shiying; Herbst, Elizabeth B; Pye, Stephen D; Moran, Carmel M; Hossack, John A

    2017-01-01

    Pipe (vessel) phantoms mimicking human tissue and blood flow are widely used for cardiovascular related research in medical ultrasound. Pipe phantom studies require the development of materials and liquids that match the acoustic properties of soft tissue, blood vessel wall, and blood. Over recent years, pipe phantoms have been developed to mimic the molecular properties of the simulated blood vessels. In this paper, the design, construction, and functionalization of pipe phantoms are introduced and validated for applications in molecular imaging and ultrasound imaging system characterization. There are three major types of pipe phantoms introduced: 1) a gelatin-based pipe phantom; 2) a polydimethylsiloxane-based pipe phantom; and 3) the "Edinburgh pipe phantom." These phantoms may be used in the validation and assessment of the dynamics of microbubble-based contrast agents and, in the case of a small diameter tube phantom, for assessing imaging system spatial resolution/contrast performance. The materials and procedures required to address each of the phantoms are described.

  3. Fabrication of Two Flow Phantoms for Doppler Ultrasound Imaging.

    Science.gov (United States)

    Zhou, Xiaowei; Kenwright, David A; Wang, Shiying; Hossack, John A; Hoskins, Peter R

    2017-01-01

    Flow phantoms are widely used in studies associated with Doppler ultrasound measurements, acting as an effective experimental validation system in cardiovascular-related research and in new algorithm/instrumentation development. The development of materials that match the acoustic and mechanical properties of the vascular system is of great interest while designing flow phantoms. Although recipes that meet the flow phantom standard defined by the International Electrotechnical Commission 61685 are already available in the literature, the standard procedure for material preparations and phantom fabrications has not been well established. In this paper, two types of flow phantoms, with and without blood vessel mimic, are described in detail in terms of the material preparation and phantom fabrication. The phantom materials chosen for the two phantoms are from published phantom studies, and their physical properties have been investigated previously. Both the flow phantoms have been scanned by ultrasound scanners and images from different modes are presented. These phantoms may be used in the validation and characterization of Doppler ultrasound measurements in blood vessels with a diameter above 1 mm.

  4. Phantom limb pain after lower limb trauma: origins and treatments.

    Science.gov (United States)

    Foell, Jens; Bekrater-Bodmann, Robin; Flor, Herta; Cole, Jonathan

    2011-12-01

    Phantom sensations, that is, sensations perceived in a body part that has been lost, are a common consequence of accidental or clinical extremity amputations. Most amputation patients report a continuing presence of the limb, with some describing additional sensations such as numbness, tickling, or cramping of the phantom limb. The type, frequency, and stability of these phantom sensations can vary immensely. The phenomenon of painful phantom sensations, that is, phantom limb pain, presents a challenge for practitioners and researchers and is often detrimental to the patient's quality of life. In addition to the use of conventional therapies for chronic pain disorders, recent years have seen the development of novel treatments for phantom limb pain, based on an increasing body of research on neurophysiological changes after amputation. This article describes the current state of research in regard to the demographics, causal factors, and treatments of phantom limb pain.

  5. Semen collection using phantom in dromedary camel.

    Science.gov (United States)

    Ziapour, S; Niasari-Naslaji, A; Mirtavousi, M; Keshavarz, M; Kalantari, A; Adel, H

    2014-12-10

    Semen collection is relatively long, unsafe, and tedious procedure in dromedary camel. The innovation of safe, hygienic, and simple approach to collect semen could make great progress in development of AI program in this species. This study investigated two methods of semen collection using phantom and artificial vagina in dromedary camel. Semen was collected using phantom (n = 4 bulls; 26 collections) and artificial vagina (n = 6 bulls; 11 collections) and diluted with INRA96 at the ratio of 1:10. The duration of semen collection, semen parameters, and morphometric features of sperm were evaluated. For specimen collected through phantom and AV, the respected duration of semen collection (411.2 ± 48.19 vs 326 ± 37.05 sec), volume (6.6 ± 0.87 vs 6 ± 1.57 ml), osmolarity (328 ± 1.6 vs 319.4 ± 3.21 mOsm/kg H2O), pH (7.7 ± 0.06 vs 7.9 ± 0.16) of semen, concentration (161.4 ± 44.05 × 10(6)/mL vs 160.2 ± 58.42 × 10(6)/mL), total motility (84.1 ± 1.89 vs 78.3 ± 3.97%), progressive forward motility (45.5 ± 3.69 vs 44.3 ± 6.41%), live percentage (72.2 ± 3.11 vs 76 ± 2.53%), and plasma membrane integrity (61.5 ± 2.49 vs 58.9 ± 4.19%) of sperm were similar (P > 0.05). The number of specimens contaminated with visible particles was greater using AV (72.7%) compared to phantom (0%; P dromedary camel.

  6. Pediatric phantom vision (Charles Bonnet) syndrome.

    OpenAIRE

    Mewasingh, Leena D.; Kornreich, Charles; Christiaens, Florence; Christophe, Catherine; Dan, Bernard

    2002-01-01

    Visual symptomatology in childhood often presents diagnostic difficulties. Recurrent paroxysmal visual complaints, although typically associated with migraine, may also signal other disorders. We describe a 9-year-old partially sighted male with paroxysmal zoopsias resulting from Charles Bonnet syndrome. This condition is characterized by paroxysmal visual hallucinations occurring in patients with chronic visual impairment, akin to the phantom-limb phenomenon. This pediatric case is the fourt...

  7. Pediatric phantom vision (Charles Bonnet) syndrome.

    Science.gov (United States)

    Mewasingh, Leena D; Kornreich, Charles; Christiaens, Florence; Christophe, Catherine; Dan, Bernard

    2002-02-01

    Visual symptomatology in childhood often presents diagnostic difficulties. Recurrent paroxysmal visual complaints, although typically associated with migraine, may also signal other disorders. We describe a 9-year-old partially sighted male with paroxysmal zoopsias resulting from Charles Bonnet syndrome. This condition is characterized by paroxysmal visual hallucinations occurring in patients with chronic visual impairment, akin to the phantom-limb phenomenon. This pediatric case is the fourth report of this condition. We have reviewed the other cases.

  8. Phantoms for Radiation Measurements of Mobile Phones

    DEFF Research Database (Denmark)

    Pedersen, Gert Frølund

    2001-01-01

    Measurements of radiation efficiency for a handheld phone equipped with a patch and a helical antenna operated near the human user have been performed. Both measurements include a simple head plus hand phantom and live persons are considered. The position of the hand on the phone is found...... to be the main reason for the large variation in radiation efficiency among persons. The tilt angle of the phone and the distance between the head and phone only play a minor role...

  9. Research cooperation report for fiscal 1997 on the environment-friendly system for effectively utilizing water resources; 1997 nendo kankyo taiogata mizushigen yuko riyo system ni kansuru kenkyu kyoryoku itaku gyomu hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    This effort exerted in cooperation with the Philippines aims to solve problems related to water resources such as stable supply and pollution of water through developing a waste water treatment/water reuse system which is easy to operate and maintain, and low in price. The ultimate goal includes (1) the construction of a waste water treatment/water reuse system comprising an anaerobic reaction tank and activated charcoal absorption tower, easy to operate and maintain, and low in price, (2) the employment of goods procurable in the Philippines, the goods including carriers for use in the anaerobic reaction tank, microbes for use in both aerobic and anaerobic reaction tanks, and activated charcoal for use in waste water reutilization, and (3) the establishment of optimum operating conditions for the waste water treatment/water reuse system by use of a pilot plant and the transfer of operating and managing techniques to the Filipino counterpart. In this fiscal year, investigations are conducted to disclose the actualities of waste water treatment and water consumption by primary industries in the vicinity of Laguna de Bay, and the waste water to be the object of study and the place of pilot plant installation have been selected. Also conducted are investigations into the carrier, microbe, activated charcoal, etc., for use in the anaerobic reaction tank. (NEDO)

  10. Automatic Synthesis of Anthropomorphic Pulmonary CT Phantoms.

    Directory of Open Access Journals (Sweden)

    Daniel Jimenez-Carretero

    Full Text Available The great density and structural complexity of pulmonary vessels and airways impose limitations on the generation of accurate reference standards, which are critical in training and in the validation of image processing methods for features such as pulmonary vessel segmentation or artery-vein (AV separations. The design of synthetic computed tomography (CT images of the lung could overcome these difficulties by providing a database of pseudorealistic cases in a constrained and controlled scenario where each part of the image is differentiated unequivocally. This work demonstrates a complete framework to generate computational anthropomorphic CT phantoms of the human lung automatically. Starting from biological and image-based knowledge about the topology and relationships between structures, the system is able to generate synthetic pulmonary arteries, veins, and airways using iterative growth methods that can be merged into a final simulated lung with realistic features. A dataset of 24 labeled anthropomorphic pulmonary CT phantoms were synthesized with the proposed system. Visual examination and quantitative measurements of intensity distributions, dispersion of structures and relationships between pulmonary air and blood flow systems show good correspondence between real and synthetic lungs (p > 0.05 with low Cohen's d effect size and AUC values, supporting the potentiality of the tool and the usefulness of the generated phantoms in the biomedical image processing field.

  11. Automatic Synthesis of Anthropomorphic Pulmonary CT Phantoms

    Science.gov (United States)

    Jimenez-Carretero, Daniel; San Jose Estepar, Raul; Diaz Cacio, Mario; Ledesma-Carbayo, Maria J.

    2016-01-01

    The great density and structural complexity of pulmonary vessels and airways impose limitations on the generation of accurate reference standards, which are critical in training and in the validation of image processing methods for features such as pulmonary vessel segmentation or artery–vein (AV) separations. The design of synthetic computed tomography (CT) images of the lung could overcome these difficulties by providing a database of pseudorealistic cases in a constrained and controlled scenario where each part of the image is differentiated unequivocally. This work demonstrates a complete framework to generate computational anthropomorphic CT phantoms of the human lung automatically. Starting from biological and image-based knowledge about the topology and relationships between structures, the system is able to generate synthetic pulmonary arteries, veins, and airways using iterative growth methods that can be merged into a final simulated lung with realistic features. A dataset of 24 labeled anthropomorphic pulmonary CT phantoms were synthesized with the proposed system. Visual examination and quantitative measurements of intensity distributions, dispersion of structures and relationships between pulmonary air and blood flow systems show good correspondence between real and synthetic lungs (p > 0.05 with low Cohen’s d effect size and AUC values), supporting the potentiality of the tool and the usefulness of the generated phantoms in the biomedical image processing field. PMID:26731653

  12. Development of A phantom for ophthalmic beta source applicator quality control using TL dosimetry

    Science.gov (United States)

    Barbosa, N. A.; da Rosa, L. A. R.; Braz, D.

    2015-11-01

    Concave eye applicators with 90Sr/90Y and 106Ru/106Rh beta ray sources are usually used in brachytherapy for the treatment of superficial intraocular tumors as uveal melanoma with thickness up to 5 mm. The calculation of the dose delivered to the eye is carried out based on the data present in the beta source calibration certificate. Therefore, it would be interesting to have a system that could evaluate that dose. In this work, an eye phantom to be used with 106Ru/106Rh betatherapy applicators was developed in solid water. This phantom can hold nine micro-cube thermoluminescent (TL) dosimeters, TLD-100. The characteristics of the TL response of the dosimeters, namely reproducibility and individual sensitivity, were determined for a 60Co source. Using Monte Carlo code MCNPX, the dose to a water eye was determined at different depths. Exposing the eye phantom with TL dosimeters to the 106Ru/106Rh applicator, it is possible to assess calibration factors using the dose values obtained by Monte Carlo simulation to each depth. Using mean calibration factors, dose values obtained by TL dosimetry were compared to the data present in the applicators certificate. Mean differences for both applicators were lower than ±10%, maximum value 17% and minimum value 0.08%. Considering that the certificate values present an uncertainty of ±20%, the calibration procedure and the developed phantom are validated and can be applied.

  13. A study of partial volume effect on SPECT imaging using myocardial phantom. With HCM (ASH) model myocardial phantom

    Energy Technology Data Exchange (ETDEWEB)

    Onoguchi, Masahisa [Kanazawa Univ. (Japan). School of Medicine

    1997-05-01

    In order to evaluate simultaneously both myocardial perfusion and regional wall motion using ECG-gated myocardial SPECT imaging, correction for the partial volume effect (PVE) should be performed. For the quantitative analysis of myocardial SPECT imaging in patients with hypertrophic cardiomyopathy (HCM), we formed a new phantom simulating HCM with various septal wall thicknesses and estimated PVE using the recovery coefficient (RC). The value of RC in all phantoms increased with increasing thickness of the septal wall reaching a plateau at 25 mm for the cylindrical phantom and 25 mm for the Ep-phantom. Compared with the RC value, the PMMA-phantom had little influence on PVE. Therefore, our results suggested that the count in the septal wall could be underestimated if PVE was corrected by the value obtained for the cylindrical phantom. In conclusion, our new phantom simulating HCM was useful in assessing PVE in the hypertrophic septal wall. (author)

  14. Analysis of 193 Mammographic phantom images

    Energy Technology Data Exchange (ETDEWEB)

    Son, Eun Ju; Kim, Eun Kyung; Ko, Kyung Hee; Kim, Young Ah; Oh, Ki Keun [College of Medicine, Yonsei Univ., Seoul (Korea, Republic of); Chung, Sun Yang [College of Medicine, Pochon CHA Univ., Pochon (Korea, Republic of); Kim, Hyuk Joo; Cha, Seung Hwan [Korea Food and Drug Administration, Seoul (Korea, Republic of)

    2003-11-01

    To evaluate the actual state of quality control in Korea through analysis of mammographic phantom images obtained from a multicenter, and to determine the proper exposure conditions required in order to obtain satisfactory phantom images. Between April and June, 2002, 193 phantom images were referred to the Korea Food and Drug Administration for evaluation. Two radiologists recorded the number of fibers, specks and masses they contained, and the 'pass' criteria were as follows: checked number of fibers: four or more; specks, three or more; masses, three or more (a total of ten or more features). Images in which optical density was over 1.2 were classified as satisfactory. In addition, changes in the success ratio, and difference between the two groups (i.e. 'pass' and 'fail', with regard to exposure conditions and optical density) were evaluated. Among the 193 images, 116 (60.1%) passed and 77 (39.9%) failed. Among those which passed, 73/100 (73%) involved to use of a grid, 80/117 (68.3%) were obtained within the optimal kVp range, 50/111 (45.0%) involved the use of optimal mAs, and 79/112 (70.5%) were obtained within the optimal range of optical density. Among those which failed, the corresponding figures were 17/52 (32.6%), 33/66 (50.0%), 31/69 (44.9%), and 35/65 (53.8%), There were statistically significant differences between the pass and fail rates, and with regard to kVp, optical density, and the use of a grid, but with regard to mAs, statistical differences were not significant. If only phantom images with an optical density of over 1.2 [as per the rule of the Mammographic Quality Standard Act (MQSA)] was included, the success rate would fall from 60.1% to 43.0%. The pass rate for mammographic phantom images was 60.1%. If such images are to be satisfactory, they should be obtained within the optimal range of optical density, using optimal kVp and a grid.

  15. Development of a dual phantom technique for measuring the fast neutron component of dose in boron neutron capture therapy

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, Yoshinori, E-mail: yosakura@rri.kyoto-u.ac.jp; Tanaka, Hiroki; Kondo, Natsuko; Kinashi, Yuko; Suzuki, Minoru; Masunaga, Shinichiro; Ono, Koji; Maruhashi, Akira [Kyoto University Research Reactor Institute, Asashironishi 2-1010, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

    2015-11-15

    Purpose: Research and development of various accelerator-based irradiation systems for boron neutron capture therapy (BNCT) is underway throughout the world. Many of these systems are nearing or have started clinical trials. Before the start of treatment with BNCT, the relative biological effectiveness (RBE) for the fast neutrons (over 10 keV) incident to the irradiation field must be estimated. Measurements of RBE are typically performed by biological experiments with a phantom. Although the dose deposition due to secondary gamma rays is dominant, the relative contributions of thermal neutrons (below 0.5 eV) and fast neutrons are virtually equivalent under typical irradiation conditions in a water and/or acrylic phantom. Uniform contributions to the dose deposited from thermal and fast neutrons are based in part on relatively inaccurate dose information for fast neutrons. This study sought to improve the accuracy in the dose estimation for fast neutrons by using two phantoms made of different materials in which the dose components can be separated according to differences in the interaction cross sections. The development of a “dual phantom technique” for measuring the fast neutron component of dose is reported. Methods: One phantom was filled with pure water. The other phantom was filled with a water solution of lithium hydroxide (LiOH) capitalizing on the absorbing characteristics of lithium-6 (Li-6) for thermal neutrons. Monte Carlo simulations were used to determine the ideal mixing ratio of Li-6 in LiOH solution. Changes in the depth dose distributions for each respective dose component along the central beam axis were used to assess the LiOH concentration at the 0, 0.001, 0.01, 0.1, 1, and 10 wt. % levels. Simulations were also performed with the phantom filled with 10 wt. % {sup 6}LiOH solution for 95%-enriched Li-6. A phantom was constructed containing 10 wt. % {sup 6}LiOH solution based on the simulation results. Experimental characterization of the

  16. SU-E-J-49: Design and Fabrication of Custom 3D Printed Phantoms for Radiation Therapy Research and Quality Assurance

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, C; Xing, L [Stanford University, Stanford, CA (United States)

    2015-06-15

    Purpose The rapid proliferation of affordable 3D printing techniques has enabled the custom fabrication of items ranging from paper weights to medical implants. This study investigates the feasibility of utilizing the technology for developing novel phantoms for use in radiation therapy quality assurance (QA) procedures. Methods A phantom for measuring the geometric parameters of linear accelerator (LINAC) on-board imaging (OBI) systems was designed using SolidWorks. The design was transferred to a 3D printer and fabricated using a fused deposition modeling (FDM) technique. Fiducials were embedded in the phantom by placing 1.6 mm diameter steel balls in predefined holes and securing them with silicone. Several MV and kV images of the phantom were collected and the visibility and geometric accuracy were evaluated. A second phantom, for use in the experimental evaluation of a high dose rate (HDR) brachytherapy dosimeter, was designed to secure several applicator needles in water. The applicator was fabricated in the same 3D printer and used for experiments. Results The general accuracy of printed parts was determined to be 0.1 mm. The cost of materials for the imaging and QA phantoms were $22 and $5 respectively. Both the plastic structure and fiducial markers of the imaging phantom were visible in MV and kV images. Fiducial marker locations were determined to be within 1mm of desired locations, with the discrepancy being attributed to the fiducial attachment process. The HDR phantom secured the applicators within 0.5 mm of the desired locations. Conclusion 3D printing offers an inexpensive method for fabricating custom phantoms for use in radiation therapy quality assurance. While the geometric accuracy of such parts is limited compared to more expensive methods, the phantoms are still highly functional and provide a unique opportunity for rapid fabrication of custom phantoms for use in radiation therapy QA and research.

  17. Attenuation correction effects on SPECT/CT procedures: phantoms studies.

    Science.gov (United States)

    Oliveira, M L; Seren, M E G; Rocha, F C; Brunetto, S Q; Ramos, C D; Button, V L S N

    2013-01-01

    Attenuation correction is widely used in SPECT/CT (Single Photon Emission Computed Tomography) procedures, especially for imaging of the thorax region. Different compensation methods have been developed and introduced into clinical practice. Most of them use attenuation maps obtained using transmission scanning systems. However, this gives extra dose of radiation to the patient. The purpose of this study was to identify when attenuation correction is really important during SPECT/CT procedures.For this purpose, we used Jaszczak phantom and phantom with three line sources, filled with technetium ((99m)-Tc), with scattering materials, like air, water and acrylic, in different detectors configurations. In all images acquired were applied analytic and iterative reconstruction algorithms; the last one with or without attenuation correction. We analyzed parameters such as eccentricity, contrast and spatial resolution in the images.The best reconstruction algorithm on average was iterative, for images with 128 × 128 and 64 × 64 matrixes. The analytical algorithm was effective only to improve eccentricity in 64 × 64 matrix and matrix in contrast 128 × 128 with low statistics. Turning to the clinical routine examinations, on average, for 128 × 128 matrix and low statistics counting, the best algorithm was the iterative, without attenuation correction,improving in 150% the three parameters analyzed and, for the same matrix size, but with high statistical counting, iterative algorithm with attenuation correction was 25% better than that without correction. We can conclude that using the iterative algorithm with attenuation correction in the water, and its extra dose given, is not justified for the procedures of low statistic counting, being relevant only if the intention is to prioritize contrast in acquisitions with high statistic counting.

  18. Phantom testis syndrome: prevalence, phenomenology and putative mechanisms.

    Science.gov (United States)

    Pühse, Gerald; Wachsmuth, Julia Urte; Kemper, Sebastian; Husstedt, Ingo W; Kliesch, Sabine; Evers, Stefan

    2010-02-01

    Chronic phantom pain has been found in up to 78% of limb amputees and is a major complication of limb amputation. Less is known about phantom phenomena after the amputation of other, i.e. visceral, parts of the body. In a retrospective design, we identified 539 patients in whom one testis was removed between 1995 and 2005. The operative technique was a unilateral standard radical inguinal orchiectomy. The underlying pathology in all cases was a testicular germ cell tumour. All patients received a detailed questionnaire asking about the occurrence of phantom testis pain (pain felt in the removed testis), phantom testis sensations (non-painful sensations as if the removed testis was still intact) and hallucinations (illusionary perceptions on the removed testis). Furthermore, we asked about the occurrence and clinical presentation of pain before and after surgery and about pre-operative testicular pain. Out of 238 respondents, 125 patients (53%) reported any kind of phantom experience. The prevalence of phantom testis pain was 25% (60/238), non-painful phantom sensations 16% (37/238) and male gonad hallucinations 12% (28/238). Patients with phantom symptoms reported pre-operative pain in the removed testis more often than patients without phantom symptoms. This study presents first data on the clinical characteristics and possible mechanisms of the phantom testis syndrome after surgical removal of one testis.

  19. An anthropomorphic multimodality (CT/MRI) head phantom prototype for end-to-end tests in ion radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Gallas, Raya R.; Huenemohr, Nora; Runz, Armin; Niebuhr, Nina I.; Greilich, Steffen [German Cancer Research Center (DKFZ), Heidelberg (Germany). Div. of Medical Physics in Radiation Oncology; National Center for Radiation Research in Oncology, Heidelberg (Germany). Heidelberg Institute of Radiation Oncology (HIRO); Jaekel, Oliver [German Cancer Research Center (DKFZ), Heidelberg (Germany). Div. of Medical Physics in Radiation Oncology; National Center for Radiation Research in Oncology, Heidelberg (Germany). Heidelberg Institute of Radiation Oncology (HIRO); Heidelberg University Hospital (Germany). Dept. of Radiation Oncology; Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg (Germany)

    2015-07-01

    With the increasing complexity of external beam therapy ''end-to-end'' tests are intended to cover every step from therapy planning through to follow-up in order to fulfill the higher demands on quality assurance. As magnetic resonance imaging (MRI) has become an important part of the treatment process, established phantoms such as the Alderson head cannot fully be used for those tests and novel phantoms have to be developed. Here, we present a feasibility study of a customizable multimodality head phantom. It is initially intended for ion radiotherapy but may also be used in photon therapy. As basis for the anthropomorphic head shape we have used a set of patient computed tomography (CT) images. The phantom recipient consisting of epoxy resin was produced by using a 3D printer. It includes a nasal air cavity, a cranial bone surrogate (based on dipotassium phosphate), a brain surrogate (based on agarose gel), and a surrogate for cerebrospinal fluid (based on distilled water). Furthermore, a volume filled with normoxic dosimetric gel mimicked a tumor. The entire workflow of a proton therapy could be successfully applied to the phantom. CT measurements revealed CT numbers agreeing with reference values for all surrogates in the range from 2 HU to 978 HU (120 kV). MRI showed the desired contrasts between the different phantom materials especially in T2-weighted images (except for the bone surrogate). T2-weighted readout of the polymerization gel dosimeter allowed approximate range verification.

  20. In-phantom two-dimensional thermal neutron distribution for intraoperative boron neutron capture therapy of brain tumours

    Science.gov (United States)

    Yamamoto, T.; Matsumura, A.; Yamamoto, K.; Kumada, H.; Shibata, Y.; Nose, T.

    2002-07-01

    The aim of this study was to determine the in-phantom thermal neutron distribution derived from neutron beams for intraoperative boron neutron capture therapy (IOBNCT). Gold activation wires arranged in a cylindrical water phantom with (void-in-phantom) or without (standard phantom) a cylinder styrene form placed inside were irradiated by using the epithermal beam (ENB) and the mixed thermal-epithermal beam (TNB-1) at the Japan Research Reactor No 4. With ENB, we observed a flattened distribution of thermal neutron flux and a significantly enhanced thermal flux delivery at a depth compared with the results of using TNB-1. The thermal neutron distribution derived from both the ENB and TNB-1 was significantly improved in the void-in-phantom, and a double high dose area was formed lateral to the void. The flattened distribution in the circumference of the void was observed with the combination of ENB and the void-in-phantom. The measurement data suggest that the ENB may provide a clinical advantage in the form of an enhanced and flattened dose delivery to the marginal tissue of a post-operative cavity in which a residual and/or microscopically infiltrating tumour often occurs. The combination of the epithermal neutron beam and IOBNCT will improve the clinical results of BNCT for brain tumours.

  1. An analytical formalism to calculate phantom scatter factors for flattening filter free (FFF) mode photon beams.

    Science.gov (United States)

    Chung, Heeteak; Prado, Karl L; Yi, Byong Yong

    2014-02-21

    Phantom Scatter Factors, Sp in the Khan formalism (Khan et al 1980 J. Radiat. Oncol. Biol. Phys. 6 745-51) describe medium-induced changes in photon-beam intensity as a function of size of the beam. According to the British Journal of Radiology, Supplement 25, megavoltage phantom scatter factors are invariant as a function of photon-beam energy. However, during the commissioning of an accelerator with flattening filter free (FFF) photon beams (Varian TrueBeam(TM) 6-MV FFF and 10-MV FFF), differences were noted in phantom scatter between the filtered beams and FFF-mode beams. The purpose of this work was to evaluate this difference and provide an analytical formalism to explain the phantom scatter differences between FFF-mode and the filtered mode. An analytical formalism was devised to demonstrate the source of phantom scatter differences between the filtered and the FFF-mode beams. The reason for the differences in the phantom scatter factors between the filtered and the FFF-mode beams is hypothesized to be the non-uniform beam profiles of the FFF-mode beams. The analytical formalism proposed here is based on this idea, taking the product of the filtered phantom scatter factors and the ratio of the off-axis ratio between the FFF-mode and the filtered beams. All measurements were performed using a Varian TrueBeam(TM) linear accelerator with photon energies of 6-MV and 10-MV in both filtered and FFF-modes. For all measurements, a PTW Farmer type chamber and a Scanditronix CC04 cylindrical ionization were used. The in-water measurements were made at depth dose maximum and 100 cm source-to-axis distance. The in-air measurements were done at 100 cm source-to-axis distance with appropriate build-up cap. From these measurements, the phantom scatter factors were derived for the filtered beams and the FFF-mode beams for both energies to be evaluated against the phantoms scatter factors calculated using the proposed algorithm. For 6-MV, the difference between the measured

  2. SU-E-T-282: Dose Measurements with An End-To-End Audit Phantom for Stereotactic Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R; Artschan, R [Calvary Mater Newcastle, Newcastle, NSW (Australia); Thwaites, D [University of Sydney, Sydney, NSW (Australia); Lehmann, J [Calvary Mater Newcastle, Newcastle, NSW (Australia); University of Sydney, Sydney, NSW (Australia)

    2015-06-15

    Purpose: Report on dose measurements as part of an end-to-end test for stereotactic radiotherapy, using a new audit tool, which allows audits to be performed efficiently either by an onsite team or as a postal audit. Methods: Film measurements have been performed with a new Stereotactic Cube Phantom. The phantom has been designed to perform Winston Lutz type position verification measurements and dose measurements in one setup. It comprises a plastic cube with a high density ball in its centre (used for MV imaging with film or EPID) and low density markers in the periphery (used for Cone Beam Computed Tomography, CBCT imaging). It also features strategically placed gold markers near the posterior and right surfaces, which can be used to calculate phantom rotations on MV images. Slit-like openings allow insertion of film or other detectors.The phantom was scanned and small field treatment plans were created. The fields do not traverse any inhomogeneities of the phantom on their paths to the measurement location. The phantom was setup at the delivery system using CBCT imaging. The calculated treatment fields were delivered, each with a piece of radiochromic film (EBT3) placed in the anterior film holder of the phantom. MU had been selected in planning to achieve similar exposures on all films. Calibration films were exposed in solid water for dose levels around the expected doses. Films were scanned and analysed following established procedures. Results: Setup of the cube showed excellent suitability for CBCT 3D alignment. MV imaging with EPID allowed for clear identification of all markers. Film based dose measurements showed good agreement for MLC created fields down to 0.5 mm × 0.5 mm. Conclusion: An end-to-end audit phantom for stereotactic radiotherapy has been developed and tested.

  3. SU-E-J-209: Geometric Distortion at 3T in a Commercial 4D MRI-Compatible Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Fatemi-Ardekani, A; Wronski, M; Kim, A; Stanisz, G; Sarfehnia, A; Keller, B [Sunnybrook Health Sciences Centre, Toronto, ON (Canada)

    2015-06-15

    Purpose: There are very few commercial 4D phantoms that are marketed as MRI compatible. We are evaluating one such commercial phantom, made to be used with an MRI-Linear accelerator. The focus of this work is to characterize the geometric distortions produced in this phantom at 3T using 3 clinical MR pulse sequences. Methods: The CIRS MRI-Linac Dynamic Phantom (CIRSTM) under investigation in this study consists of a softwaredriven moving tumour volume within a thorax phantom body and enables dose accumulation by placing a dosimeter within the tumour volume. Our initial investigation is to evaluate the phantom in static mode prior to examining its 4D capability. The water-filled thorax phantom was scanned using a wide-bore Philips 3T Achieva MRI scanner employing a Thoracic xl coil and clinical 2D T1W FFE, 2D T1W TSE and 3D T1W TFE pulse sequences. Each of the MR image sets was rigidly fused with a reference CT image of the phantom employing a rigid registration with 6 degrees of freedom. Geometric distortions between the MR and CT image sets were measured in 3 dimensions at selected points along the periphery of the distortion grid embedded within the phantom body (11.5, 7.5 and 3 cm laterally, ant/post and sup/inf of magnetic isocenter respectively). Results: The maximal measured geometric distortions between the MR and reference CT points of interest were 0.9, 1.8 and 1.3 mm in the lateral, anteriorposterior and cranio-caudal directions, respectively. For all 3 spatial dimensions, the maximal distortions occurred for the FFE pulse sequence. Maximal distortions for the 2D FFE, 2D TSE and 3D TFE sequences were 1, 0.7 and 1.8 mm, respectively. Conclusion: Our initial static investigation of this phantom shows minimal geometric distortions at 3T along the periphery of the embedded grid. CIRS has provided us with a phantom at no charge for evaluation at 3 Tesla.

  4. Characterization of a phantom setup for breast conserving cancer surgery

    Science.gov (United States)

    Chadwell, Jacob T.; Conley, Rebekah H.; Collins, Jarrod A.; Meszoely, Ingrid M.; Miga, Michael I.

    2016-03-01

    The purpose of this work is to develop an anatomically and mechanically representative breast phantom for the validation of breast conserving surgical therapies, specifically, in this case, image guided surgeries. Using three patients scheduled for lumpectomy and four healthy volunteers in mock surgical presentations, the magnitude, direction, and location of breast deformations was analyzed. A phantom setup was then designed to approximate such deformations in a mock surgical environment. Specifically, commercially available and custom-built polyvinyl alcohol (PVA) phantoms were used to mimic breast tissue during surgery. A custom designed deformation apparatus was then created to reproduce deformations seen in typical clinical setups of the pre- and intra-operative breast geometry. Quantitative analysis of the human subjects yielded a positive correlation between breast volume and amount of breast deformation. Phantom results reflected similar behavior with the custom-built PVA phantom outperforming the commercial phantom.

  5. Phantom limb pain from spinal sarcoma: a case report.

    Science.gov (United States)

    Cruz, Ernesto; Dangaria, Harsh T

    2013-07-01

    Phantom limb pain is a frequent sequela of amputation. A high prevalence of residual limb pain and back pain also exists among amputees. We present a case of a new-onset severe phantom limb pain resulting from a metastatic spinal mass in an 81-year-old patient with a history of malignant sarcoma and an old hip disarticulation amputation. The metastatic lesion, upon imaging, was found to involve the L3 vertebra and caused moderate compression of the thecal sac on the right and severe right lateral recess stenosis. After the mass was resected, the patient's phantom limb pain resolved. Our case report demonstrates that spinal metastatic pathologies may be a cause of phantom limb pain and should be included in the differential diagnosis of new-onset phantom limb pain or a change in phantom limb pain.

  6. Polarized light propagation through tissue and tissue phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Sankaran, V; Walsh, J T JR; Maitland, D J

    2000-02-08

    We show that standard tissue phantoms can be used to mimic the intensity and polarization properties of tissue. Polarized light propagation through biologic tissue is typically studied using tissue phantoms consisting of dilute aqueous suspensions of microspheres. The dilute phantoms can empirically match tissue polarization and intensity properties. One discrepancy between the dilute phantoms and tissue exist: common tissue phantoms, such as dilute Intralipid and dilute 1-{micro}m-diameter polystyrene microsphere suspensions, depolarize linearly polarized light more quickly than circularly polarized light. In dense tissue, however, where scatterers are often located in close proximity to one another, circularly polarized light is depolarized similar to or more quickly than linearly polarized light. We also demonstrate that polarized light propagates differently in dilute versus densely packed microsphere suspensions, which may account for the differences seen between polarized light propagation in common dilute tissue phantoms versus dense biologic tissue.

  7. Development of thyroid anthropomorphic phantoms for use in nuclear medicine

    Science.gov (United States)

    Cerqueira, R. A. D.; Maia, A. F.

    2014-02-01

    The objective of this study was to develop thyroid anthropomorphic phantoms to be used in control tests of medical images in scintillation cameras. The main difference among the phantoms was the neck shape: in the first, called OSCT, it was geometrically shaped, while in the second, called OSAP, it was anthropomorphically shaped. In both phantoms, thyroid gland prototypes, which were made of acrylic and anthropomorphically shaped, were constructed to allow the simulation of a healthy thyroid and of thyroids with hyperthyroidism and hypothyroidism. Images of these thyroid anthropomorphic phantoms were obtained using iodine 131 with an activity of 8.695 MBq. The iodine 131 was chosen because it is widely used in studies of thyroid scintigraphy. The images obtained proved the effectiveness of the phantoms to simulate normal or abnormal thyroids function. These phantoms can be used in medical imaging quality control programs and, also in the training of professionals involved in the analysis of images in nuclear medicine centers.

  8. New asymptotically flat phantom wormhole solutions

    CERN Document Server

    Lobo, Francisco S N; Riazi, Nematollah

    2012-01-01

    A possible cause of the late-time cosmic acceleration is an exotic fluid with an equation of state lying within the phantom regime, i.e., $w=p/\\rho 0. Thus, there is no need to surgically paste the interior wormhole geometry to an exterior vacuum spacetime. We also consider the "volume integral quantifier", which provides useful information regarding the total amount of energy condition violating matter, and show that, in principle, it is possible to construct asymptotically flat wormhole solutions with an arbitrary small amount of energy condition violating matter.

  9. Computerized acoustical characterization system of medical phantoms

    Science.gov (United States)

    Nazihah, M. D.; Kadri, S.; Yaacob, M. I. H.; Rosly, J.

    2013-05-01

    The development of a computerized acoustical characterization system of medical phantoms is described in this paper. The system employs the insertion technique and it was developed using LabView 2011 where the ultrasound signal was acquired through the interfacing scheme of an oscilloscope to a personal computer. The system performance was validated by comparing measured acoustical properties with values obtained from the previous studies. Other than faster measurement time, the developed system carried percentage difference at less than 1.00% for all of the acoustical properties measurements at 23.0°C to 25.0°C respectively.

  10. Phantom Energy with Variable G and A

    Institute of Scientific and Technical Information of China (English)

    Arbab Ⅰ. Arbab

    2008-01-01

    @@ We investigate a cosmological model of a phantom energy with a variable cosmological constant (A) depending on the energy density (p) as A α ρ-α, α = const and a variable gravitational constant G. The model requires α -1 and α 0 and p decrease with cosmic expansion. For ordinary energy (or dark energy), i.e.ω > -1, we have -1 0 so that G > 0 increases with time and ρ decreases with time. Cosmic acceleration with dust particles is granted, provided -2/3 0.

  11. Dosimeter placement in the Rando phantom

    Energy Technology Data Exchange (ETDEWEB)

    Archer, B.R.; Glaze, S.; North, L.B.; Bushong, S.C.

    1977-07-01

    Each section of the Alderson Rando phantom contains a tissue-equivalent plastic coating layer approximately 2 mm thick, applied to both faces. This compensates for material removed in the sawing process. Conventional use of thermoluminescent dosimeters positions them totally or partially within the coating layer. Analysis shows that, in the lung region, dosimeters placed in this layer received a dose averaging 39% lower than those placed at midsection. Where bony structures interfere, some dosimeters in the coating layer received an 18% higher dose than those at midsection. Therefore, positioning dosimeters at the center of a section is recommended.

  12. Phantom erectile penis after sex reassignment surgery

    Directory of Open Access Journals (Sweden)

    Kimata,Yoshihiro

    2008-06-01

    Full Text Available Between January 2001 and December 2007, we performed vaginoplasty as sex reassignment surgery in a total of 14 male-to-female transsexual (MTFTS patients [1]. Several complications occurred such as partial flap necrosis, rectovaginal fistula formation and hypersensitivity of the neoclitoris. Just after the operation, some patients feel that their penises still exist, but by several weeks postoperatively, this sensation has disappeared. Herein we report a case of MTFTS in whom the sensation of a phantom erectile penis persisted for much longer.

  13. Intercostal HIFU Treatment: A Tissue Phantom

    Science.gov (United States)

    Illing, Rowland O.; Kennedy, James E.; ter Haar, Gail R.

    2005-03-01

    High-intensity focused ultrasound (HIFU) when used clinically to treat liver and kidney tumours is often directed between the ribs. This paper details the construction of a tissue phantom, incorporating ribs, and its use to assess the clinical safety of HIFU exposures. The prefocal, acoustic side-lobes of the ultrasonic beam were studied with and without rib interference, and thermocouples used to assess in-situ temperature changes. The results show that there are implications in regards to the safety of clinical treatment, should the operator be unaware of the characteristics of the transducer being used.

  14. Getting started with PhantomJS

    CERN Document Server

    Beltran, Aries

    2013-01-01

    The book will follow aA standard tutorial approach, and will beas a complete guide detailing the major aspects of PhantomJS with particular focus on Website website Testingtesting.This book is written forIf you are a JavaScript developers who are is interested in developing applications that interact with various web services, and doing that using a headless browser, then this book is ideal for you. This book iswill also be good for you if you are planning to create a headless browser testing for your web application. Basic understanding of JavaScript is assumed.

  15. Viscous dark energy and phantom evolution

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Mauricio [Departamento de Fisica, Facultad de Ciencias, Universidad del Bio-Bio, Avenida Collao 1202, Casilla 5-C, Concepcion (Chile)]. E-mail: mcataldo@ubiobio.cl; Cruz, Norman [Departamento de Fisica, Facultad de Ciencia, Universidad de Santiago, Casilla 307, Santiago (Chile)]. E-mail: ncruz@lauca.usach.cl; Lepe, Samuel [Instituto de Fisica, Facultad de Ciencias Basicas y Matematicas, Pontificia Universidad Catolica de Valparaiso, Avenida Brasil 2950, Valparaiso (Chile)]. E-mail: slepe@ucv.cl

    2005-07-14

    In order to study if the bulk viscosity may induce a big rip singularity on the flat FRW cosmologies, we investigate dissipative processes in the universe within the framework of the standard Eckart theory of relativistic irreversible thermodynamics, and in the full causal Israel-Stewart-Hiscock theory. We have found cosmological solutions which exhibit, under certain constraints, a big rip singularity. We show that the negative pressure generated by the bulk viscosity cannot avoid that the dark energy of the universe to be phantom energy.

  16. Creating 3D gelatin phantoms for experimental evaluation in biomedicine

    Directory of Open Access Journals (Sweden)

    Stein Nils

    2015-09-01

    Full Text Available We describe and evaluate a setup to create gelatin phantoms by robotic 3D printing. Key aspects are the large workspace, reproducibility and resolution of the created phantoms. Given its soft tissue nature, the gelatin is kept fluid during inside the system and we present parameters for additive printing of homogeneous, solid objects. The results indicate that 3D printing of gelatin can be an alternative for quickly creating larger soft tissue phantoms without the need for casting a mold.

  17. [Pathogenesis of phantom limb syndrome and its treatment].

    Science.gov (United States)

    Naryshkin, A G; Gurchin, F A; Samoĭlov, K A; Kirsanova, G V; Vasilevskaia, L S; Shvets, Ia M

    1989-08-01

    The spinal mechanism of the phantom pain origin is proved. The underlying factors are: segmentary spinal denervation hypersensitivity and attenuation of the descending inhibitory influence. The pathogenetic treatment of phantom pains is proposed by means of an associated treatment by GABA-ergic drug--Baclofen and alpha-2--adrenomimetic--Clofelin. Good effects of the proposed scheme of treatment confirm the correctness of the presented ideas of pathogenesis of phantom pains.

  18. Prevalent Hallucinations during Medical Internships: Phantom Vibration and Ringing Syndromes

    OpenAIRE

    Yu-Hsuan Lin; Sheng-Hsuan Lin; Peng Li; Wei-Lieh Huang; Ching-Yen Chen

    2013-01-01

    BACKGROUND: Phantom vibration syndrome is a type of hallucination reported among mobile phone users in the general population. Another similar perception, phantom ringing syndrome, has not been previously described in the medical literature. METHODS: A prospective longitudinal study of 74 medical interns (46 males, 28 females; mean age, 24.8±1.2 years) was conducted using repeated investigations of the prevalence and associated factors of phantom vibration and ringing. The accompanying sympto...

  19. Studies on Phantom Vibration and Ringing Syndrome among Postgraduate Students

    OpenAIRE

    Atul Kumar Goyal

    2015-01-01

    Phantom vibrations and ringing of mobile phones are prevalent hallucinations in the general population. They might be considered as a normal brain mechanism. The aim of this study was to establish the prevalence of Phantom vibrations and ringing syndrome among students and to assess factors associated it. The survey of 300 postgraduate students belonging to different field of specialization was conducted at Kurukshetra University. 74% of students were found to have both Phantom vibrations and...

  20. PREFACE: Cooperative dynamics Cooperative dynamics

    Science.gov (United States)

    Gov, Nir

    2011-09-01

    The dynamics within living cells are dominated by non-equilibrium processes that consume chemical energy (usually in the form of ATP, adenosine triphosphate) and convert it into mechanical forces and motion. The mechanisms that allow this conversion process are mostly driven by the components of the cytoskeleton: (i) directed (polar) polymerization of filaments (either actin or microtubules) and (ii) molecular motors. The forces and motions produced by these two components of the cytoskeleton give rise to the formation of cellular shapes, and drive the intracellular transport and organization. It is clear that these systems present a multi-scale challenge, from the physics of the molecular processes to the organization of many interacting units. Understanding the physical nature of these systems will have a large impact on many fundamental problems in biology and break new grounds in the field of non-equilibrium physics. This field of research has seen a rapid development over the last ten years. Activities in this area range from theoretical and experimental work on the underlying fundamental (bio)physics at the single-molecule level, to investigations (in vivo and in vitro) of the dynamics and patterns of macroscopic pieces of 'living matter'. In this special issue we have gathered contributions that span the whole spectrum of length- and complexity-scales in this field. Some of the works demonstrate how active forces self-organize within the polymerizing cytoskeleton, on the level of cooperative cargo transport via motors or due to active fluxes at the cell membrane. On a larger scale, it is shown that polar filaments coupled to molecular motors give rise to a huge variety of surprising dynamics and patterns: spontaneously looping rings of gliding microtubules, and emergent phases of self-organized filaments and motors in different geometries. All of these articles share the common feature of being out-of-equilibrium, driven by metabolism. As demonstrated here

  1. Dosimetry and verification of Co total body irradiation with human phantom and semiconductor diodes.

    Science.gov (United States)

    Allahverdi, Mahmoud; Geraily, Ghazale; Esfehani, Mahbod; Sharafi, Aliakbar; Haddad, Peyman; Shirazi, Alireza

    2007-10-01

    Total Body Irradiation (TBI) is a form of radiotherapy used for patients prior to bone marrow or stem cell transplant to destroy any undetectable cancer cells. The dosimetry characteristics of a (60)Co unit for TBI were studied and a simple method for the calculation of the prescribed dose for TBI is presented. Dose homogeneity was verified in a human phantom. Dose measurements were made in water phantom (30 × 30 × 30 cm(3)), using farmer ionization chamber (0.6 cc, TM30010, PTW) and a parallel plate ionization chamber (TM23343, PTW). Point dose measurements for AP/PA irradiation were measured in a human phantom using silicon diodes (T60010L, PTW). The lung dose was measured with an ionization chamber (0.3 cc, TM31013). The validity of the proposed algorithm was checked at TBI distance using the human phantom. The accuracy of the proposed algorithm was within 3.5%. The dose delivered to the mid-lobe of the lung was 14.14 Gy and it has been reduced to 8.16 Gy by applying the proper shield. Dose homogeneity was within ±7% for all measured points. The results indicate that a good agreement between the total prescribed and calculated midplane doses can be achieved using this method. Therefore, it could be possible to use calculated data for TBI treatments.

  2. Galileons, phantom fields, and the fate of the Universe

    Science.gov (United States)

    Shahalam, M.; Pacif, S. K. J.; Myrzakulov, R.

    2016-07-01

    In this paper we study cosmological dynamics of the phantom as well as non-phantom fields with a linear potential in the presence of a Galileon correction (partial _μ φ partial ^μ φ ) Box φ . We show that the Big Crunch singularity is delayed compared to the standard case; the delay crucially depends upon the strength of a Galileon correction. As for the phantom Galileon, ρ _{φ } is shown to grow more slowly compared to the standard phantom delaying the approach of the singularity. In the case, V˜ φ ^n, n>4, Big Rip is also delayed, similar phenomenon is shown to take place for potentials steeper than the exponential.

  3. Breast phantom for mammary tissue characterization by near infrared spectroscopy

    Science.gov (United States)

    Miranda, D. A.; Cristiano, K. L.; Gutiérrez, J. C.

    2013-11-01

    Breast cancer is a disease associated to a high morbidity and mortality in the entire world. In the study of early detection of breast cancer the development of phantom is so important. In this research we fabricate a breast phantom using a ballistic gel with special modifications to simulate a normal and abnormal human breast. Optical properties of woman breast in the near infrared region were modelled with the phantom we developed. The developed phantom was evaluated with near infrared spectroscopy in order to study its relation with breast tissue. A good optical behaviour was achieved with the model fabricated.

  4. Theoretical analysis of phantom rotations in BSD-DTI.

    Science.gov (United States)

    Krzyzak, Artur; Borkowski, Karol

    2015-08-01

    A novel method of improving accuracy of diffusion tensor imaging (DTI), called BSD-DTI (B-spatial distribution in DTI), has been recently proposed. Determination of the b matrix components using an anisotropic phantom, and derivation of the spatial distribution are of the essence in this approach. So far, a sufficient uniformity of the diffusion properties across the entire phantom has been assumed. Nevertheless, BSD-DTI is not limited only to highly homogeneous phantoms. This study describes a procedure which allows to use basically any anisotropic phantom of a precisely defined structure.

  5. Non-Gaussian statistical properties of virtual breast phantoms

    Science.gov (United States)

    Abbey, Craig K.; Bakic, Predrag R.; Pokrajac, David D.; Maidment, Andrew D. A.; Eckstein, Miguel P.; Boone, John M.

    2014-03-01

    Images derived from a "phantom" are useful for characterizing the performance of imaging systems. In particular, the modulation transfer properties of imaging detectors are traditionally assessed by physical phantoms consisting of an edge. More recently researchers have come to realize that quantifying the effects of object variability can also be accomplished with phantoms in modalities such as breast imaging where anatomical structure may be the principal limitation in performance. This has driven development of virtual phantoms that can be used in simulation environments. In breast imaging, several such phantoms have been proposed. In this work, we analyze non-Gaussian statistical properties of virtual phantoms, and compare them to similar statistics from a database of breast images. The virtual phantoms assessed consist of three classes. The first is known as clustered-blob lumpy backgrounds. The second class is "binarized" textures which typically apply some sort of threshold to a stochastic 3D texture intended to represent the distribution of adipose and glandular tissue in the breast. The third approach comes from efforts at the University of Pennsylvania to directly simulate the 3D anatomy of the breast. We use Laplacian fractional entropy (LFE) as a measure of the non-Gaussian statistical properties of each simulation. Our results show that the simulation approaches differ considerably in LFE with very low scores for the clustered-blob lumpy background to very high values for the UPenn phantom. These results suggest that LFE may have value in developing and tuning virtual phantom simulation procedures.

  6. [Development of a software for 3D virtual phantom design].

    Science.gov (United States)

    Zou, Lian; Xie, Zhao; Wu, Qi

    2014-02-01

    In this paper, we present a 3D virtual phantom design software, which was developed based on object-oriented programming methodology and dedicated to medical physics research. This software was named Magical Phan tom (MPhantom), which is composed of 3D visual builder module and virtual CT scanner. The users can conveniently construct any complex 3D phantom, and then export the phantom as DICOM 3.0 CT images. MPhantom is a user-friendly and powerful software for 3D phantom configuration, and has passed the real scene's application test. MPhantom will accelerate the Monte Carlo simulation for dose calculation in radiation therapy and X ray imaging reconstruction algorithm research.

  7. Phantom Eye Syndrome: A Review of the Literature

    Directory of Open Access Journals (Sweden)

    Agda M. Andreotti

    2014-01-01

    Full Text Available The purpose of this literature review was to describe the main features of phantom eye syndrome in relation to their possible causes, symptoms, treatments, and influence of eye amputation on quality of life of anophthalmic patients. For this, a bibliographical research was performed in Pubmed database using the following terms: “eye amputation,” “eye trauma,” “phantom eye syndrome,” “phantom pain,” and “quality of life,” associated or not. Thirteen studies were selected, besides some relevant references contained in the selected manuscripts and other studies hallowed in the literature. Thus, 56 articles were included in this review. The phantom eye syndrome is defined as any sensation reported by the patient with anophthalmia, originated anophthalmic cavity. In phantom eye syndrome, at least one of these three symptoms has to be present: phantom vision, phantom pain, and phantom sensations. This syndrome has a direct influence on the quality of life of the patients, and psychological support is recommended before and after the amputation of the eyeball as well as aid in the treatment of the syndrome. Therefore, it is suggested that, for more effective treatment of phantom eye syndrome, drug therapy should be associated with psychological approach.

  8. Supply and Marketing Cooperatives

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ China Supply and Marketing Cooperatives Council of CCPIT was established in March 1996. It is an institution under direct leadership of China Supply and Market-ing Cooperatives and at the same time a branch of China Council for Promotion of International Trade, with its major task to promoting and facilitating export-oriented economic trade and technological cooper-ation of the national supply and marketing cooperative system.

  9. A BrachyPhantom for verification of dose calculation of HDR brachytherapy planning system

    Energy Technology Data Exchange (ETDEWEB)

    Austerlitz, C. [Clinica Diana Campos, Recife, PE 52020-030 (Brazil); Campos, C. A. T. [Pontifícia Universidade Católica do Rio de Janeiro, RJ 22451-900 (Brazil)

    2013-11-15

    Purpose: To develop a calibration phantom for {sup 192}Ir high dose rate (HDR) brachytherapy units that renders possible the direct measurement of absorbed dose to water and verification of treatment planning system.Methods: A phantom, herein designated BrachyPhantom, consists of a Solid Water™ 8-cm high cylinder with a diameter of 14 cm cavity in its axis that allows the positioning of an A1SL ionization chamber with its reference measuring point at the midheight of the cylinder's axis. Inside the BrachyPhantom, at a 3-cm radial distance from the chamber's reference measuring point, there is a circular channel connected to a cylindrical-guide cavity that allows the insertion of a 6-French flexible plastic catheter from the BrachyPhantom surface. The PENELOPE Monte Carlo code was used to calculate a factor, P{sub sw}{sup lw}, to correct the reading of the ionization chamber to a full scatter condition in liquid water. The verification of dose calculation of a HDR brachytherapy treatment planning system was performed by inserting a catheter with a dummy source in the phantom channel and scanning it with a CT. The CT scan was then transferred to the HDR computer program in which a multiple treatment plan was programmed to deliver a total dose of 150 cGy to the ionization chamber. The instrument reading was then converted to absorbed dose to water using the N{sub gas} formalism and the P{sub sw}{sup lw} factor. Likewise, the absorbed dose to water was calculated using the source strength, S{sub k}, values provided by 15 institutions visited in this work.Results: A value of 1.020 (0.09%, k= 2) was found for P{sub sw}{sup lw}. The expanded uncertainty in the absorbed dose assessed with the BrachyPhantom was found to be 2.12% (k= 1). To an associated S{sub k} of 27.8 cGy m{sup 2} h{sup −1}, the total irradiation time to deliver 150 cGy to the ionization chamber point of reference was 161.0 s. The deviation between the absorbed doses to water assessed with

  10. Pre-treatment radiotherapy dose verification using Monte Carlo doselet modulation in a spherical phantom

    CERN Document Server

    Townson, Reid W

    2013-01-01

    Due to the increasing complexity of radiotherapy delivery, accurate dose verification has become an essential part of the clinical treatment process. The purpose of this work was to develop an electronic portal image (EPI) based pre-treatment verification technique capable of quickly reconstructing 3D dose distributions from both coplanar and non-coplanar treatments. The dose reconstruction is performed in a spherical water phantom by modulating, based on EPID measurements, pre-calculated Monte Carlo (MC) doselets defined on a spherical coordinate system. This is called the spherical doselet modulation (SDM) method. This technique essentially eliminates the statistical uncertainty of the MC dose calculations by exploiting both azimuthal symmetry in a patient-independent phase-space and symmetry of a virtual spherical water phantom. The symmetry also allows the number of doselets necessary for dose reconstruction to be reduced by a factor of about 250. In this work, 51 doselets were used. The SDM method mitiga...

  11. Phantom black holes and critical phenomena

    CERN Document Server

    Azreg-Aïnou, Mustapha; Rodrigues, Manuel E

    2014-01-01

    We consider the two classes cosh and sinh of normal and phantom black holes of Einstein-Maxwell-Dilaton theory. Leaving aside the normal Reissner-Nordstr\\"om black hole, it is shown that only some phantom black holes of both classes exhibit critical phenomena. The two classes share a nonextremality, but special, critical point where the transition is continuous. This point yields a classification scheme for critical points. It is concluded that the two unstable and stable phases coexist on one side of the criticality state and disappear on the other side, that is, there is no configuration where only one phase exists. The sinh class has an extremality critical point where the entropy diverges. The transition from extremality to nonextremality with the charge held constant is accompanied by a loss of mass and an increase in the temperature. A special case of this transition is when the hole is isolated (microcanonical ensemble), it will evolve by emission of energy, which results in a decrease of its mass, to ...

  12. Examining the Viability of Phantom Dark Energy

    CERN Document Server

    Ludwick, Kevin J

    2015-01-01

    In the standard cosmological framework of the 0th-order FLRW metric and the use of perfect fluids in the stress-energy tensor, dark energy with an equation-of-state parameter $w < -1$ (known as phantom dark energy) implies negative kinetic energy and vacuum instability when modeled as a scalar field. However, the value of best fit from Planck and WMAP9 for present-day $w$ is indeed less than $-1$. We find that it is not as obvious as one might think that phantom dark energy has negative kinetic energy categorically. Staying within the confines of observational constraints and general relativity, for which there is good experimental validation, we consider a few reasonable departures from the standard 0th-order framework in an attempt to see if negative kinetic energy can be avoided in these settings despite an apparent $w<-1$. We consider a more accurate description of the universe through the perturbing of the isotropic and homogeneous FLRW metric and the components of the stress-energy tensor, and we ...

  13. Application of a pelvic phantom in brachytherapy dosimetry for high-dose-rate (HDR) 192Ir source based on Monte Carlo simulations

    Science.gov (United States)

    Ahn, Woo Sang; Choi, Wonsik; Shin, Seong Soo; Jung, Jinhong

    2014-08-01

    In this study, we evaluate how the radial dose function is influenced by the source position as well as the phantom size and shape. A pelvic water phantom similar to the pelvic shape of a human body was designed by averaging dimensions obtained from computed tomography (CT) images of patients treated with brachytherapy for cervical cancer. Furthermore, for the study of the effects of source position on the dose distribution, the position of the source in the water phantom was determined by using the center of mass of the gross target volume (GTV) in the CT images. To obtain the dosimetric parameter of a high-dose-rate (HDR) 192Ir source, we performed Monte Carlo simulations by using the Monte Carlo n-particle extended code (MCNPX). The radial dose functions obtained using the pelvic water phantom were compared with those of spherical phantom with different sizes, including the Monte Carlo (MC) results of Williamson and Li. Differences between the radial dose functions from this study and the data in the literature increased with the radial distances. The largest differences appeared for spherical phantom with the smallest size. In contrast to the published MC results, the radial dose function of the pelvic water phantom significantly decreased with radial distance in the vertical direction because full scattering was not possible. When the source was located in posterior position 2 cm from the center in the pelvic water phantom, the differences between the radial dose functions rapidly decreased with the radial distance in the lower vertical direction. If the International Commission on Radiation Units and Measurements bladder and rectum points are considered, doses to these reference points could be underestimated by up to 1%-2% at a distance of 3 to 6 cm. Our simulation results provide a valid clinical reference data and can used to improve the accuracy of the doses delivered during brachytherapy applied to patients with cervical cancer.

  14. Gredos San Diego Cooperative. Cooperate to undertake

    Directory of Open Access Journals (Sweden)

    Carlos de la Higuera

    2012-12-01

    Full Text Available This paper analyzes the cooperative experience through Gredos San Diego model, its institutional approaches and its history from the point of view of management, focusing on the variables that enable the success of a collective ownership institution. First, the author makes a brief analysis of the principles that guide the cooperative, its origins and its current situation, including the development of GSD Cooperative Group. It continues exploring the evolution of management, dividing it into four distinct stages, and concludes with a summary with the findings of the previous president of the cooperative.Received: 23.07.2012Accepted: 10.09.2012

  15. SU-E-T-454: Impact of Air Gap On PDDs of 6 MV Photon Beam for Various Field Sizes in Inhomogeneous Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Oyewale, S [Cancer Centers of Southwest Oklahoma, Lawton, OK (United States); Pokharel [21st Century Oncology, Estero, FL (United States); Singh, H [Procure Proton Therapy Center, Oklahoma City, OK (United States); Islam, M [University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Rana, S [ProCure Proton Therapy Center, Oklahoma City, OK (United States)

    2015-06-15

    Purpose: To investigate how the shape of air gap and its size will impact the percent depth doses (PDDs) of a 6MV photon beam for various field sizes. Methods: Two in-house phantoms were manufactured containing rectangular (phantom A) and circular (phantom B) air gaps. Both phantoms A and B were composed of same top layer (solid-water; 30×30cm{sup 2},5cm thickness) and bottom layer (solid-water; 30×30cm {sup 2},8cm thickness), but middle layer was varied to observe air gap effects and scatter contribution to the measurement point. In phantom A, a rectangular shaped air gap (30×30cm{sup 2},7cm thickness) was created by placing Styrofoam blocks between top and bottom layers of the phantom. In phantom B, middle layer was replaced by “inhomogenous block”, composed of acrylic plate (30×30cm{sup 2}, 4cm thickness) followed by PVC(30×30cm{sup 2},3cm thickness). Additionally, circular air gap was created by drilling a hole (diameter=2.8cm, length=7cm) at the center of “inhomogenous block”. In both phantoms, measurement readings were obtained at 13cm depth (i.e., 1cm after air gap) and depth of maximum dose(6MV energy; 100 MUs; field sizes ranged from 3×3cm{sup 2} to 10×10cm{sup 2}). The PDDs at 13cm depth were compared in both phantoms. Results: The measurements in both phantoms A and B showed an almost linear increase in PDDs with increasing field size, especially for smaller field sizes (from 3×3 to 7×7cm{sup 2}). For each field size, the PDD in phantom A was smaller compared to the one in phantom B. The difference in PDDs between two phantoms decreased with an increase in field size as the PDD difference decreased from 9.0% to 6.4%. Conclusion: The shape and size of air gap affect the PDD measurements in secondary build-up region as 6 MV primary beam traverses through the center of air gap. The scatter contribution due to increase in field size was more noticeable for field sizes ≤7×7cm{sup 2}.

  16. Radiological response and dosimetry in physical phantom of head and neck for 3D conformational radiotherapy; Resposta radiologica e dosimetria em phantom fisico de cabeca e pescoco para radioterapia conformacional 3D

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa

    2013-07-01

    Phantoms are tools for simulation of organs and tissues of the human body in radiology and radiotherapy. This thesis describes the development, validation and, most importantly, the use of a physical head and neck phantom in radiology and radiotherapy, with the purpose of evaluating dose distribution using Gafchromic EBT2 film in 15 MV 3D conformal radiotherapy. The work was divided in two stages, (1) development of new equivalent tissues and improvement of the physical phantom, and (2) use of the physical phantom in experimental dosimetry studies. In phase (1) parameters such as mass density, chemical composition of tissues, anatomical and biometric measurements were considered, as well as aspects of imaging by computed tomography (CT) and radiological response representation in Hounsfield Units (HU), which were compared with human data. Radiological experiments of in-phantom simulated brain pathologies were also conducted. All those results matched human-sourced data, therefore the physical phantom is a suitable simulator that may be used to enhance radiological protocols and education in medical imaging. The main objective in phase (2) was to evaluate the spatial dose distribution in a brain tumor simulator inserted inside the head and neck phantom developed by the Ionizing Radiation Research Group (NRI), exposed to 15 MV 3D conformal radiotherapy, for internal dose assessment. Radiation planning was based on CT images of the physical phantom with a brain tumor simulator made with equivalent material. The treatment planning system (TPS), CAT3D software, used CT images and prescribed a dose of 200 cGy, distributed in three fields of radiation, in a T-shaped pattern. The TPS covered the planning treatment volume (PTV) with 97% of the prescribed dose. A solid water phantom and radiochromic Gafchromic EBT2 film were used for calibration procedures, generating a dose response curve as a function of optical density (OD). After calibration and irradiation, the film

  17. Development of anatomically and dielectrically accurate breast phantoms for microwave imaging applications

    Science.gov (United States)

    O'Halloran, M.; Lohfeld, S.; Ruvio, G.; Browne, J.; Krewer, F.; Ribeiro, C. O.; Inacio Pita, V. C.; Conceicao, R. C.; Jones, E.; Glavin, M.

    2014-05-01

    Breast cancer is one of the most common cancers in women. In the United States alone, it accounts for 31% of new cancer cases, and is second only to lung cancer as the leading cause of deaths in American women. More than 184,000 new cases of breast cancer are diagnosed each year resulting in approximately 41,000 deaths. Early detection and intervention is one of the most significant factors in improving the survival rates and quality of life experienced by breast cancer sufferers, since this is the time when treatment is most effective. One of the most promising breast imaging modalities is microwave imaging. The physical basis of active microwave imaging is the dielectric contrast between normal and malignant breast tissue that exists at microwave frequencies. The dielectric contrast is mainly due to the increased water content present in the cancerous tissue. Microwave imaging is non-ionizing, does not require breast compression, is less invasive than X-ray mammography, and is potentially low cost. While several prototype microwave breast imaging systems are currently in various stages of development, the design and fabrication of anatomically and dielectrically representative breast phantoms to evaluate these systems is often problematic. While some existing phantoms are composed of dielectrically representative materials, they rarely accurately represent the shape and size of a typical breast. Conversely, several phantoms have been developed to accurately model the shape of the human breast, but have inappropriate dielectric properties. This study will brie y review existing phantoms before describing the development of a more accurate and practical breast phantom for the evaluation of microwave breast imaging systems.

  18. Experimental dosimetric evaluation in pelvis phantom, subjected to prostate radiation therapy protocol at 15 MV Linac

    Energy Technology Data Exchange (ETDEWEB)

    Matos, Andrea Silva Dias de; Campos, Tarcisio P.R., E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Dias, Humberto Galvao [Centro de Radioterapia Hospital Luxemburgo, Belo Horizonte, MG (Brazil)

    2011-07-01

    Among the existing malignant neoplasia, the prostate cancer is most common among male population. Due to its high incidence and morbidity, there is a need for investment in advanced technology for better treatment associated with research and social mobilization to prevent the disease. As an efficient method of treatment for such tumor, radiation teletherapy brings favorable results for the patient, particularly when the cancer is diagnosed early. There are, however, the needs to assess the absorbed doses that reach the prostate in the radiation protocols in order to certify the treatment efficacy. The present research goal is to obtain the profile of absorbed dose distributed in a synthetic prostate on male pelvis phantom following a standard radiation therapy protocol. The methodology makes use of a NRI made phantom and a 15MV Linac accelerator. This phantom has anthropomorphic and anthropometric features containing the major internal organs, including bone, prostate, intestine, and bladder. The exposition was made in a 15 MV linear accelerator taken the isocenter in four fields as a 'BOX' of opposing beams. The dosimetry was prepared using GafChromic EBT type 2 radiochromic film and calibration in a solid water phantom. The radiochromic films were digitized on the Microtek Scan Maker 6900XL model scanner operating in the transmission mode and optical density readings based on RGB mode in the computer program Imagedig. The absorbance readings were performed in the spectrophotometer SP-220 mark BIOSPECTRO obtaining calibration curves generated by the collected data. The results reproduce the dose distribution generated in two orthogonal radiochromic films positioned onto the synthetic prostate. Discussions regarding the characteristics of the phantom and methods of irradiation in relation to the achieved dose profile will be addressed. (author)

  19. Development and validation of two phantoms for quality control in cone-beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Gomes B, W. O., E-mail: wilsonottobatista@gmail.com [Instituto Federal da Bahia, Rua Emidio dos Santos s/n, Barbalho 40301-015, Salvador de Bahia (Brazil)

    2016-10-15

    The cone beam computed tomography (CBCT) was introduced into the market in the late 90 s and being a relatively new technology, also no well-established quality control protocols. There are currently projects to standardize the use of CBCT. The SEDENTEXCT project was created with the goal of developing guidelines for CBCT, including the development of a phantom for quality control it is proposed. This study aimed at the development and validation of the models of phantom: CQ{sub I}FBA{sub 0}1 e CQ{sub I}FBA{sub 0}2, the first filled with water and the second fully with solid structure in PMMA. Both models allow, otherwise the European phantom - SEDENTEXCT, its use in various models of CBCT, independent of the size of the field of view. The two phantoms used to evaluate seven parameters of quality control are: intensity or average value of pixels of five different plastics, signal to noise ratio, resolution, low contrast, spatial resolution, the accuracy of distances on the z axis, the geometric distortion and image uniformity. The spatial resolution is a critical parameter that differs significantly from the other types of scan, and in these two phantom can be evaluated by two different methods: MTF obtained by Fourier transformation of the function LSF (line spread function) and/or by analysis visual image to a pattern of bars up to 16 pl/cm. Validation was performed in three models CBCT: Kodak 9000, i-CAT Classical and Orthophos XG 3-dimensional. All imaging protocols were characterized dosimetric ally with solid state sensors to correlate with the perfect operation. These models were selected by different manufacturers have different characteristics as FOV, maximum voltage, slice thickness and patient positioning mode. The two of phantom models were viable and also showed compliance with the specifications and data available in the literature. We conclude the feasibility of the two phantom models, and model option will be linked to the practicality positioning

  20. Cooperative Online Education

    Directory of Open Access Journals (Sweden)

    Morten Flate Paulsen

    2008-07-01

    Full Text Available Cooperative learning seeks to develop virtual learning environments that allow students to have optimal individual freedom within online learning communities. The pedagogical and administrative challenges with regard to accommodating both individual freedom and cooperation are explained in the Theory of Cooperative Freedom. This article shows that cooperative learning can be implemented successfully through a set of instruments or means. To illustrate this with current examples, the article presents NKI Distance Education’s surveys and experiences with cooperative learning. The article also discusses how issues such as web 2.0, transparency, learning partners and individual progression plans relate to cooperative online education.

  1. Phantom Accretion onto the Schwarzschild de-Sitter Black Hole

    Institute of Scientific and Technical Information of China (English)

    M Sharif; G Abbas

    2011-01-01

    We deal with phantom energy accretion onto the Schwarzschild de-Sitter black hole. The energy flux conservation, relativistic Bernoulli equation and mass Bux conservation equation are formulated to discuss the phantom accretion. We discuss the conditions for critical accretion. It is found that the mass of the black hole decreases due to phantom accretion. There exist two critical points which lie in the exterior of horizons (black hole and cosmological horizons). The results for the phantom energy accretion onto the Schwarzschild black hole can be recovered by taking A → 0.%@@ We deal with phantom energy accretion onto the Schwarzschild de-Sitter black hole.The energy flux conserva-tion,relativistic Bernoulli equation and mass flux conservation equation are formulated to discuss the phantom accretion.We discuss the conditions for critical accretion.It is found that the mass of the black hole decreases due to phantom accretion.There exist two critical points which lie in the exterior of horizons(black hole and cosmological horizons).The results for the phantom energy accretion onto the Schwarzschild black hole can be recovered by taking ∧→0.

  2. Evaluation of DQA for tomography using 3D volumetric phantom

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Uk [Dept. of Radiation Oncology, Catholic University of Incheon St. Mary' s Hospital, Incheon (Korea, Republic of); Kim, Jeong Koo [Dept. of Radiological Science, Hanseo University, Seosan (Korea, Republic of)

    2016-12-15

    The study investigates the necessity of 3 dimensional dose distribution evaluation instead of point dose and 2 dimensional dose distribution evaluation. Treatment plans were generated on the RANDO phantom to measure the precise dose distribution of the treatment site 0.5, 1, 1.5, 2, 2.5, 3 cm with the prescribed dose; 1,200 cGy, 5 fractions. Gamma analysis (3%/3 mm, 2%/2 mm) of dose distribution was evaluated with gafchromic EBT2 film and ArcCHECK phantom. The average error of absolute dose was measured at 0.76±0.59% and 1.37±0.76% in cheese phantom and ArcCHECK phantom respectively. The average passing ratio for 3%/3 mm were 97.72±0.02% and 99.26±0.01% in gafchromic EBT2 film and ArcCHECK phantom respectively. The average passing ratio for 2%/2 mm were 94.21±0.02% and 93.02±0.01% in gafchromic EBT2 film and ArcCHECK phantom respectively. There was a more accurate dose distribution of 3D volume phantom than cheese phantom in patients DQA using tomotherapy. Therefor it should be evaluated simultaneously 3 dimensional dose evaluation on target and peripheral area in rotational radiotherapy such as tomotherapy.

  3. Phantom jam avoidance through in-car speed advice

    NARCIS (Netherlands)

    Suijs, L.C.W.; Wismans, L.J.J.; Krol, L.; Berkum, van E.C.

    2015-01-01

    The existence of phantom jams can be explained following the definition of Kerner & Konhäuser (1993) who state that a phantom jam occurs without the existence of a physical bottleneck and is caused by the imperfect driving style of road users under metastable traffic conditions. In order to prevent

  4. Crossing the Phantom divide line in the Chaplygin gas model

    CERN Document Server

    Sadjadi, H Mohseni

    2009-01-01

    The role of the interaction in crossing the phantom divide line in the Chaplygin gas model is discussed. We obtain some general properties of the interactions that allow the model to arrive at the phantom divide line. We show that these properties put some conditions on the ratio of dark matter to dark energy density.

  5. Usefulness of milnacipran in treating phantom limb pain

    Directory of Open Access Journals (Sweden)

    Matsumoto Y

    2012-11-01

    Full Text Available Yasuhide Nagoshi,1 Akira Watanabe,1 Saiko Inoue,1 Tomoki Kuroda,2 Mitsuo Nakamura,3 Yoshitake Matsumoto,4 Kenji Fukui31Department of Psychiatry (Psychosomatic Medicine, Kyoto First Red Cross Hospital, Kyoto, Japan; 2Gojouyama Hospital, Nara, Japan; 3Department of Psychiatry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan; 4Matsumoto Clinic, Kyoto, JapanBackground: Amputation of an extremity often results in the sensation of a “phantom limb” where the patient feels that the limb that has been amputated is still present. This is frequently accompanied by “phantom limb pain”. We report here the use of milnacipran, a serotonin and norepinephrine reuptake inhibitor, to treat phantom limb pain after amputation of injured or diseased limbs in three patients.Methods and results: The severity of phantom pain before and during treatment was quantified using a visual analog scale. In one case, phantom limb pain responded partially to treatment with high doses of paroxetine, and then replacement with milnacipran further improved the pain relief and long-term full pain relief was achieved. In the two other cases, milnacipran was used as first-line treatment and phantom limb pain responded rapidly.Conclusion: These results suggest that milnacipran administration may be useful in phantom limb pain, possibly as a first-line treatment.Keywords: milnacipran, paroxetine, phantom limb pain, selective serotonin reuptake inhibitor (SSRI, serotonin and norepinephrine reuptake inhibitor (SNRI

  6. Comparison of different phantoms used in digital diagnostic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bor, Dogan, E-mail: bor@eng.ankara.edu.tr [Ankara University, Faculty of Engineering, Department of Engineering Physics. Tandogan, 06100 Ankara (Turkey); Unal, Elif, E-mail: elf.unall@gmail.com [Radat Dosimetry Laboratory Services, 06830, Golbasi, Ankara (Turkey); Uslu, Anil, E-mail: m.aniluslu@gmail.com [Radat Dosimetry Laboratory Services, 06830, Golbasi, Ankara (Turkey)

    2015-09-21

    The organs of extremity, chest, skull and lumbar were physically simulated using uniform PMMA slabs with different thicknesses alone and using these slabs together with aluminum plates and air gaps (ANSI Phantoms). The variation of entrance surface air kerma and scatter fraction with X-ray beam qualities was investigated for these phantoms and the results were compared with those measured from anthropomorphic phantoms. A flat panel digital radiographic system was used for all the experiments. Considerable variations of entrance surface air kermas were found for the same organs of different designs, and highest doses were measured for the PMMA slabs. A low contrast test tool and a contrast detail test object (CDRAD) were used together with each organ simulation of PMMA slabs and ANSI phantoms in order to test the clinical image qualities. Digital images of these phantom combinations and anthropomorphic phantoms were acquired in raw and clinically processed formats. Variation of image quality with kVp and post processing was evaluated using the numerical metrics of these test tools and measured contrast values from the anthropomorphic phantoms. Our results indicated that design of some phantoms may not be efficient enough to reveal the expected performance of the post processing algorithms.

  7. Comparison of different phantoms used in digital diagnostic imaging

    Science.gov (United States)

    Bor, Dogan; Unal, Elif; Uslu, Anil

    2015-09-01

    The organs of extremity, chest, skull and lumbar were physically simulated using uniform PMMA slabs with different thicknesses alone and using these slabs together with aluminum plates and air gaps (ANSI Phantoms). The variation of entrance surface air kerma and scatter fraction with X-ray beam qualities was investigated for these phantoms and the results were compared with those measured from anthropomorphic phantoms. A flat panel digital radiographic system was used for all the experiments. Considerable variations of entrance surface air kermas were found for the same organs of different designs, and highest doses were measured for the PMMA slabs. A low contrast test tool and a contrast detail test object (CDRAD) were used together with each organ simulation of PMMA slabs and ANSI phantoms in order to test the clinical image qualities. Digital images of these phantom combinations and anthropomorphic phantoms were acquired in raw and clinically processed formats. Variation of image quality with kVp and post processing was evaluated using the numerical metrics of these test tools and measured contrast values from the anthropomorphic phantoms. Our results indicated that design of some phantoms may not be efficient enough to reveal the expected performance of the post processing algorithms.

  8. Doctors Try Brain-Training to Curb 'Phantom Limb Pain'

    Science.gov (United States)

    ... with the study. "The problem with having a prosthetic limb is that when you try to control that hand, it does not translate. You use other parts ... needed for a patient to move their "phantom" hand, and linked those signals to a robot prosthetic limb. Patients experienced an increase in phantom pain ...

  9. The impact of anthropometric patient-phantom matching on organ dose: A hybrid phantom study for fluoroscopy guided interventions

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Perry B.; Geyer, Amy; Borrego, David; Ficarrotta, Kayla; Johnson, Kevin; Bolch, Wesley E. [Nuclear and Radiological Engineering, University of Florida, Gainesville, Florida 32611 (United States); Radiology, University of Florida, Jacksonville, Florida 32209 (United States); Department of Nuclear and Radiological/Biomedical Engineering, University of Florida, Gainesville, Florida 32611-8300 (United States)

    2011-02-15

    Purpose: To investigate the benefits and limitations of patient-phantom matching for determining organ dose during fluoroscopy guided interventions. Methods: In this study, 27 CT datasets representing patients of different sizes and genders were contoured and converted into patient-specific computational models. Each model was matched, based on height and weight, to computational phantoms selected from the UF hybrid patient-dependent series. In order to investigate the influence of phantom type on patient organ dose, Monte Carlo methods were used to simulate two cardiac projections (PA/left lateral) and two abdominal projections (RAO/LPO). Organ dose conversion coefficients were then calculated for each patient-specific and patient-dependent phantom and also for a reference stylized and reference hybrid phantom. The coefficients were subsequently analyzed for any correlation between patient-specificity and the accuracy of the dose estimate. Accuracy was quantified by calculating an absolute percent difference using the patient-specific dose conversion coefficients as the reference. Results: Patient-phantom matching was shown most beneficial for estimating the dose to heavy patients. In these cases, the improvement over using a reference stylized phantom ranged from approximately 50% to 120% for abdominal projections and for a reference hybrid phantom from 20% to 60% for all projections. For lighter individuals, patient-phantom matching was clearly superior to using a reference stylized phantom, but not significantly better than using a reference hybrid phantom for certain fields and projections. Conclusions: The results indicate two sources of error when patients are matched with phantoms: Anatomical error, which is inherent due to differences in organ size and location, and error attributed to differences in the total soft tissue attenuation. For small patients, differences in soft tissue attenuation are minimal and are exceeded by inherent anatomical differences

  10. Validation of phantom-based harmonization for patient harmonization.

    Science.gov (United States)

    Panetta, Joseph V; Daube-Witherspoon, Margaret E; Karp, Joel S

    2017-07-01

    To improve the precision of multicenter clinical trials, several efforts are underway to determine scanner-specific parameters for harmonization using standardized phantom measurements. The goal of this study was to test the correspondence between quantification in phantom and patient images and validate the use of phantoms for harmonization of patient images. The National Electrical Manufacturers' Association image quality phantom with hot spheres was scanned on two time-of-flight PET scanners. Whole-body [(18) F]-fluorodeoxyglucose (FDG)-PET scans were acquired of subjects on the same systems. List-mode events from spheres (diam.: 10-28 mm) measured in air on each scanner were embedded into the phantom and subject list-mode data from each scanner to create lesions with known uptake with respect to the local background in the phantom and each subject's liver and lung regions, as a proxy to characterize true lesion quantification. Images were analyzed using the contrast recovery coefficient (CRC) typically used in phantom studies and serving as a surrogate for the standardized uptake value used clinically. Postreconstruction filtering (resolution recovery and Gaussian smoothing) was applied to determine if the effect on the phantom images translates equivalently to subject images. Three postfiltering strategies were selected to harmonize the CRCmean or CRCmax values between the two scanners based on the phantom measurements and then applied to the subject images. Both the average CRCmean and CRCmax values for lesions embedded in the lung and liver in four subjects (BMI range 25-38) agreed to within 5% with the CRC values for lesions embedded in the phantom for all lesion sizes. In addition, the relative changes in CRCmean and CRCmax resulting from the application of the postfilters on the subject and phantom images were consistent within measurement uncertainty. Further, the root mean squared percent difference (RMSpd ) between CRC values on the two scanners

  11. In-phantom spectra and dose distributions from a high-energy neutron therapy beam

    Energy Technology Data Exchange (ETDEWEB)

    Benck, S. E-mail: benck@fynu.ucl.ac.be; D' Errico, F.; Denis, J.-M.; Meulders, J.-P.; Nath, R.; Pitcher, E.J

    2002-01-01

    In radiotherapy with external beams, healthy tissues surrounding the target volumes are inevitably irradiated. In the case of neutron therapy, the estimation of dose to the organs surrounding the target volume is particularly challenging, because of the varying contributions from primary and secondary neutrons and photons of different energies. The neutron doses to tissues surrounding the target volume at the Louvain-la-Neuve (LLN) facility were investigated in this work. At LLN, primary neutrons have a broad spectrum with a mean energy of about 30 MeV. The transport of a 10x10 cm{sup 2} beam through a water phantom was simulated by means of the Monte Carlo code MCNPX. Distributions of energy-differential values of neutron fluence, kerma and kerma equivalent were estimated at different locations in a water phantom. The evolution of neutron dose and dose equivalent inside the phantom was deduced. Measurements of absorbed dose and of dose equivalent were then carried out in a water phantom using an ionization chamber and superheated drop detectors (SDDs). On the beam axis, the calculations agreed well with the ionization chamber data, but disagreed significantly from the SDD data due to the detector's under-response to neutrons above 20 MeV. Off the beam axis, the calculated absorbed doses were significantly lower than the ionization chamber readings, since gamma fields were not accounted for. The calculated data are doses from neutron-induced charge particles, and these agreed with the values measured by the photon-insensitive SDDs. When exposed to the degraded spectra off the beam axis, the SDD offered reliable estimates of the neutron dose equivalent.

  12. Phantom space–times in fake supergravity

    Directory of Open Access Journals (Sweden)

    Maryam Bu Taam

    2015-12-01

    Full Text Available We discuss phantom metrics admitting Killing spinors in fake N=2, D=4 supergravity coupled to vector multiplets. The Abelian U(1 gauge fields in the fake theory have kinetic terms with the wrong sign. We solve the Killing spinor equations for the standard and fake theories in a unified fashion by introducing a parameter which distinguishes between the two theories. The solutions found are fully determined in terms of algebraic conditions, the so-called stabilisation equations, in which the symplectic sections are related to a set of functions. These functions are harmonic in the case of the standard supergravity theory and satisfy the wave-equation in flat (2+1-space–time in the fake theory. Explicit examples are given for the minimal models with quadratic prepotentials.

  13. Regular phantom black holes as gravitational lenses

    CERN Document Server

    Eiroa, Ernesto F

    2015-01-01

    The distortion of the spacetime structure in the surroundings of black holes affects the trajectories of light rays. As a consequence, black holes can act as gravitational lenses. Observations of type Ia supernovas, show that our Universe is in accelerated expansion. The usual explanation is that the Universe is filled with a negative pressure fluid called dark energy, which accounts for 70 % of its total density, which can be modeled by a self-interacting scalar field with a potential. We consider a class of spherically symmetric regular phantom black holes as gravitational lenses. We study large deflection angles, using the strong deflection limit, corresponding to an asymptotic logarithmic approximation. In this case, photons passing close to the photon sphere of the black hole experiment several loops around it before they emerge towards the observer, giving place to two infinite sets of relativistic images. Within this limit, we find analytical expressions for the positions and the magnifications of thes...

  14. Phantom limb pain: a nursing perspective.

    Science.gov (United States)

    Virani, Anila; Green, Theresa; Turin, Tanvir C

    2014-09-09

    Phantom limb pain (PLP) is a neuropathic pain condition occurring after amputation of a limb. PLP affects amputees' quality of life and results in loss of productivity and psychological distress. The origin of pain from a non-existing limb creates a challenging situation for both patients and nurses. It is imperative to provide patients and nurses with the knowledge that PLP is a real phenomenon that requires care and treatment. This knowledge will lead to reduced problems for patients by allowing them to talk about PLP and ask for help when needed. Understanding of this phenomenon will enable nurses to appreciate the unique features of this form of neuropathic pain and apply appropriate techniques to promote effective pain management. Performing accurate and frequent assessments to understand the unique characteristics of PLP, displaying a non-judgemental attitude towards patients and teaching throughout the peri-operative process are significant nursing interventions.

  15. Surgical phantom for off-pump mitral valve replacement

    Science.gov (United States)

    McLeod, A. Jonathan; Moore, John; Guiraudon, Gerard M.; Jones, Doug L.; Campbell, Gordon; Peters, Terry M.

    2011-03-01

    Off-pump, intracardiac, beating heart surgery has the potential to improve patient outcomes by eliminating the need for cardiopulmonary bypass and aortic cross clamping but it requires extensive image guidance as well as the development of specialized instrumentation. Previously, developments in image guidance and instrumentation were validated on either a static phantom or in vivo through porcine models. This paper describes the design and development of a surgical phantom for simulating off-pump mitral valve replacement inside the closed beating heart. The phantom allows surgical access to the mitral annulus while mimicking the pressure inside the beating heart. An image guidance system using tracked ultrasound, magnetic instrument tracking and preoperative models previously developed for off-pump mitral valve replacement is applied to the phantom. Pressure measurements and ultrasound images confirm the phantom closely mimics conditions inside the beating heart.

  16. Crossing of the phantom divide in modified gravity

    CERN Document Server

    Bamba, Kazuharu; Nojiri, Shin'ichi; Odintsov, Sergei D

    2009-01-01

    We reconstruct an explicit model of modified gravity in which a crossing of the phantom divide can be realized. It is shown that the Big Rip singularity appears in the model of modified gravity, whereas that the (finite-time) Big Rip singularity in modified gravity is transformed to the infinite-time singularity in the corresponding scalar field theory obtained through the conformal transformation. Furthermore, we investigate the relations between the scalar field theories realizing a crossing of the phantom divide and the corresponding modified gravitational theories by using the inverse conformal transformation. It is demonstrated that the scalar field theories describing the non-phantom phase (phantom one with the Big Rip) can be represented as the theories of real (complex) $F(R)$ gravity through the inverse (complex) conformal transformation. We also study a viable model of modified gravity in which the transition from the de Sitter universe to the phantom phase can occur.

  17. Phantom percepts: Tinnitus and pain as persisting aversive memory networks

    Science.gov (United States)

    De Ridder, Dirk; Elgoyhen, Ana Belen; Romo, Ranulfo; Langguth, Berthold

    2011-01-01

    Phantom perception refers to the conscious awareness of a percept in the absence of an external stimulus. On the basis of basic neuroscience on perception and clinical research in phantom pain and phantom sound, we propose a working model for their origin. Sensory deafferentation results in high-frequency, gamma band, synchronized neuronal activity in the sensory cortex. This activity becomes a conscious percept only if it is connected to larger coactivated “(self-)awareness” and “salience” brain networks. Through the involvement of learning mechanisms, the phantom percept becomes associated to distress, which in turn is reflected by a simultaneously coactivated nonspecific distress network consisting of the anterior cingulate cortex, anterior insula, and amygdala. Memory mechanisms play a role in the persistence of the awareness of the phantom percept, as well as in the reinforcement of the associated distress. Thus, different dynamic overlapping brain networks should be considered as targets for the treatment of this disorder. PMID:21502503

  18. [Mirror therapy for phantom limb pain--a systematic review].

    Science.gov (United States)

    Seidel, Stefan; Kasprian, Gregor; Sycha, Thomas; Auff, Eduard

    2009-01-01

    The aim of this review was to evaluate the evidence for the treatment of phantom limb pain with mirror therapy. Randomised controlled studies were identified by a systematic search strategy in the databases "Medline" and "The Cochrane Library". The studies were evaluated using the quality criteria of the JADAD-scale. Three small-sized randomised controlled studies were identified. Unfortunately, these studies lacked methodological quality. One of them found a significant decrease of phantom pain after four weeks of daily mirror therapy sessions. Two other studies could not find a significant difference in the reduction of phantom limb pain between intervention- and control-groups. To date, there is only circumstantial evidence for mirror therapy in phantom pain. Hence, no firm recommendations regarding this treatment option are possible. More sufficiently powered randomised controlled studies with high methodological quality are mandatory to investigate the analgesic effect of mirror therapy in phantom limb pain.

  19. New Phantom and non-Phantom Wormhole Solutions with Generic Cosmological Constant

    CERN Document Server

    Heydarzade, Y; Moradpour, H

    2014-01-01

    There are a number of reasons to study wormholes with generic cosmological constant $\\Lambda$. Recent observations indicate that present accelerating expansion of the universe demands $\\Lambda>0$. On the other hand, some extended theories of gravitation such as supergravity and superstring theories posses vacuum states with $\\Lambda<0$. Even within the framework of general relativity, a negative cosmological constant permits black holes with horizons topologically different from the usual spherical ones. These solutions are convertible to wormhole solutions by adding some exotic matter. In this paper, the phantom and non-phantom matter wormhole solutions in the presence of cosmological constant are studied. By constructing a specific class of shape functions, mass function, energy density and pressure profiles which support such a geometry are obtained. It is shown that for having such a geometry, the wormhole throat $r_0$, the cosmological constant $\\Lambda$ and the equation of state parameter $\\omega$ sh...

  20. Technical Note: Multipurpose CT, ultrasound, and MRI breast phantom for use in radiotherapy and minimally invasive interventions

    Energy Technology Data Exchange (ETDEWEB)

    Ruschin, Mark, E-mail: Mark.Ruschin@sunnybrook.ca; Chin, Lee; Ravi, Ananth; McCann, Claire [Department of Medical Physics, Sunnybrook Odette Cancer Centre, Toronto, Ontario M4N 3M5, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M4N 3M5 (Canada); Davidson, Sean R. H. [Techna Institute, University Health Network, Toronto, Ontario M5G 1P5 (Canada); Phounsy, William [Department of Physics, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Yoo, Tae Sun [Institute of Health Policy, University of Toronto, Toronto, Ontario M5T 3M6 (Canada); Pignol, Jean-Philippe [Department of Radiation Oncology, Erasmus MC Cancer Institute, 3075 EA Rotterdam (Netherlands)

    2016-05-15

    Purpose: To develop a multipurpose gel-based breast phantom consisting of a simulated tumor with realistic imaging properties in CT, ultrasound and MRI, or a postsurgical cavity on CT. Applications for the phantom include: deformable image registration (DIR) quality assurance (QA), autosegmentation validation, and localization testing and training for minimally invasive image-guided procedures such as those involving catheter or needle insertion. Methods: A thermoplastic mask of a typical breast patient lying supine was generated and then filled to make an array of phantoms. The background simulated breast tissue consisted of 32.4 g each of ballistic gelatin (BG) powder and Metamusil™ (MM) dissolved in 800 ml of water. Simulated tumors were added using the following recipe: 12 g of barium sulfate (1.4% v/v) plus 0.000 14 g copper sulfate plus 0.7 g of MM plus 7.2 g of BG all dissolved in 75 ml of water. The phantom was evaluated quantitatively in CT by comparing Hounsfield units (HUs) with actual breast tissue. For ultrasound and MRI, the phantoms were assessed based on subjective image quality and signal-difference to noise (SDNR) ratio, respectively. The stiffness of the phantom was evaluated based on ultrasound elastography measurements to yield an average Young’s modulus. In addition, subjective tactile assessment of phantom was performed under needle insertion. Results: The simulated breast tissue had a mean background value of 24 HU on CT imaging, which more closely resembles fibroglandular tissue (40 HU) as opposed to adipose (−100 HU). The tumor had a mean CT number of 45 HU, which yielded a qualitatively realistic image contrast relative to the background either as an intact tumor or postsurgical cavity. The tumor appeared qualitatively realistic on ultrasound images, exhibiting hypoechoic characteristics compared to background. On MRI, the tumor exhibited a SDNR of 3.7. The average Young’s modulus was computed to be 15.8 ± 0.7 kPa (1 SD

  1. Validation study of the thorax phantom Lungman for optimization purposes

    Science.gov (United States)

    Rodríguez Pérez, Sunay; Marshall, Nicholas W.; Struelens, Lara; Bosmans, Hilde

    2017-03-01

    This work aims to investigate the advantages and limitations of the Kyoto Kagaku thorax phantom Lungman for use in chest radiography optimization studies. First, patient survey data were gathered for chest posterior anterior (PA) and lateral (LAT) examinations in a standard chest X-ray room over a period of one year, using a Caesium Iodide (CsI) based flat panel detector with automatic exposure control (AEC). Parameters surveyed included exposure index (EI), dose area product (DAP) and AEC exposure time. PA and LAT projections of the phantom were then compared to these values. Additionally, the equivalence in millimetres of poly (methyl methacrylate) (PMMA) was established for the different regions of the Lungman phantom (lungs and mediastinum). Finally, a voxel model of the Lungman phantom was developed by the segmentation of a volumetric dataset of the phantom acquired using CT scanning. Subsequently, the model was used in Monte Carlo simulations with PENELOPE/penEasy code to calculate the energy deposited in the organs of the phantom. This enabled comparison of the phantom tissue-equivalent materials with materials defined by ICRP 89 in terms of energy deposition. For the survey data, close agreement was found between phantom and the median values for the patient data (deviations ranged from 4% to 31%, one outlier). The phantom lung region is equivalent to 89 mm to 106 mm of PMMA, depending on tube voltage. Energy deposited in the phantom material compared to those for ICRP defined material differed by at most 36% in AP irradiations and 49% in PA irradiations.

  2. Phantom breast sensations and phantom breast pain : A 2-year prospective study and a methodological analysis of literature

    NARCIS (Netherlands)

    Dijkstra, P.U.; Rietman, J.S.; Geertzen, J.H.B.

    The first aim of this study was to assess prospectively the incidence of phantom breast sensations (PB sensations) and phantom breast pain (PB pain) in a sample of patients treated for breast cancer (n = 204) by means of a modified radical mastectomy (n = 82). Patients were assessed 6 weeks, 6, 12

  3. Phantom breast sensations and phantom breast pain : A 2-year prospective study and a methodological analysis of literature

    NARCIS (Netherlands)

    Dijkstra, P.U.; Rietman, J.S.; Geertzen, J.H.B.

    2007-01-01

    The first aim of this study was to assess prospectively the incidence of phantom breast sensations (PB sensations) and phantom breast pain (PB pain) in a sample of patients treated for breast cancer (n = 204) by means of a modified radical mastectomy (n = 82). Patients were assessed 6 weeks, 6, 12 a

  4. Cooperative Tagging Center (CTC)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Cooperative Tagging Center (CTC) began as the Cooperative Game Fish Tagging Program (GTP) at Woods Hole Oceanographic Institute (WHOI) in 1954. The GTP was...

  5. Activation rate uniformity in a bilateral IVNAA facility for two anthropomorphic phantoms

    Directory of Open Access Journals (Sweden)

    Miri Hakimabad Hashem

    2010-01-01

    Full Text Available Activation rate uniformity is the first property which is considered in the design of a prompt γ-ray in vivo neutron activation analysis facility. Preliminary studies on the activation rate distribution in the body can be done by use of Monte Carlo codes, such as the MCNP. In this paper, different bilateral configurations of an IVNAA system are considered in order to improve the activation rate uniformity in a water phantom measuring 32 cm x 100 cm x 16 cm. In the best case, uniformity parameters are U = 1.003 and R = 1.67, with the mean activation rate of 1.85×10-6 cm-3. In more accurate calculations, the water phantom is replaced by a body model. The model in question is a 5 year-old ORNL phantom filled with just soft tissue. For uniformity studies, the internal organs are not simulated. Finally, uniformity parameters in this case are U = 1.005 and R = 12.2.

  6. Comparison of measured and Monte Carlo calculated dose distributions in inhomogeneous phantoms in clinical electron beams

    Science.gov (United States)

    Doucet, R.; Olivares, M.; DeBlois, F.; Podgorsak, E. B.; Kawrakow, I.; Seuntjens, J.

    2003-08-01

    Calculations of dose distributions in heterogeneous phantoms in clinical electron beams, carried out using the fast voxel Monte Carlo (MC) system XVMC and the conventional MC code EGSnrc, were compared with measurements. Irradiations were performed using the 9 MeV and 15 MeV beams from a Varian Clinac-18 accelerator with a 10 × 10 cm2 applicator and an SSD of 100 cm. Depth doses were measured with thermoluminescent dosimetry techniques (TLD 700) in phantoms consisting of slabs of Solid WaterTM (SW) and bone and slabs of SW and lung tissue-equivalent materials. Lateral profiles in water were measured using an electron diode at different depths behind one and two immersed aluminium rods. The accelerator was modelled using the EGS4/BEAM system and optimized phase-space files were used as input to the EGSnrc and the XVMC calculations. Also, for the XVMC, an experiment-based beam model was used. All measurements were corrected by the EGSnrc-calculated stopping power ratios. Overall, there is excellent agreement between the corrected experimental and the two MC dose distributions. Small remaining discrepancies may be due to the non-equivalence between physical and simulated tissue-equivalent materials and to detector fluence perturbation effect correction factors that were calculated for the 9 MeV beam at selected depths in the heterogeneous phantoms.

  7. Comparison of measured and Monte Carlo calculated dose distributions in inhomogeneous phantoms in clinical electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Doucet, R [Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Ave Cedar, Montreal H3G 1A4 (Canada); Olivares, M [Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Ave Cedar, Montreal H3G 1A4 (Canada); DeBlois, F [Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Ave Cedar, Montreal H3G 1A4 (Canada); Podgorsak, E B [Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Ave Cedar, Montreal H3G 1A4 (Canada); Kawrakow, I [National Research Council Canada, Ionizing Radiation Standards Group, Ottawa K1A 0R6, Canada (Canada); Seuntjens, J [Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Ave Cedar, Montreal H3G 1A4 (Canada)

    2003-08-07

    Calculations of dose distributions in heterogeneous phantoms in clinical electron beams, carried out using the fast voxel Monte Carlo (MC) system XVMC and the conventional MC code EGSnrc, were compared with measurements. Irradiations were performed using the 9 MeV and 15 MeV beams from a Varian Clinac-18 accelerator with a 10 x 10 cm{sup 2} applicator and an SSD of 100 cm. Depth doses were measured with thermoluminescent dosimetry techniques (TLD 700) in phantoms consisting of slabs of Solid Water{sup TM} (SW) and bone and slabs of SW and lung tissue-equivalent materials. Lateral profiles in water were measured using an electron diode at different depths behind one and two immersed aluminium rods. The accelerator was modelled using the EGS4/BEAM system and optimized phase-space files were used as input to the EGSnrc and the XVMC calculations. Also, for the XVMC, an experiment-based beam model was used. All measurements were corrected by the EGSnrc-calculated stopping power ratios. Overall, there is excellent agreement between the corrected experimental and the two MC dose distributions. Small remaining discrepancies may be due to the non-equivalence between physical and simulated tissue-equivalent materials and to detector fluence perturbation effect correction factors that were calculated for the 9 MeV beam at selected depths in the heterogeneous phantoms.

  8. Extensive Dialogues and Cooperation

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Chinese Taipei On March 23,Chairman Wan Jifei of the China Council for the Promotion of International Trade (CCPIT) and Board Chairman Wang Zhigang of the Taipei World Trade Center (TWTC) signed a cooperation agreement at the Taipei World Trade Tower,marking the new page of the development of cooperation and relations between the two organizations and the establishment of their cooperation mechanism.

  9. Sorting and sustaining cooperation

    DEFF Research Database (Denmark)

    Vikander, Nick

    2013-01-01

    This paper looks at cooperation in teams where some people are selfish and others are conditional cooperators, and where lay-offs will occur at a fixed future date. I show that the best way to sustain cooperation prior to the lay-offs is often in a sorting equilibrium, where conditional cooperato...

  10. Designing for cooperation - cooperating in design

    DEFF Research Database (Denmark)

    Kyng, Morten

    1991-01-01

    This article will discuss how to design computer applications that enhance the quality of work and products, and will relate the discussion to current themes in the field of Computer-Supported Cooperative Work (CSCW). Cooperation is a key element of computer use and work practice, yet here...... a specific "CSCW approach is not taken." Instead the focus is cooperation as an important aspect of work that should be integrated into most computer support efforts in order to develop successful computer support, however, other aspects such as power, conflict and control must also be considered....

  11. An anatomically realistic temperature phantom for radiofrequency heating measurements.

    Science.gov (United States)

    Graedel, Nadine N; Polimeni, Jonathan R; Guerin, Bastien; Gagoski, Borjan; Wald, Lawrence L

    2015-01-01

    An anthropomorphic phantom with realistic electrical properties allows for a more accurate reproduction of tissue current patterns during excitation. A temperature map can then probe the worst-case heating expected in the unperfused case. We describe an anatomically realistic human head phantom that allows rapid three-dimensional (3D) temperature mapping at 7T. The phantom was based on hand-labeled anatomical imaging data and consists of four compartments matching the corresponding human tissues in geometry and electrical properties. The increases in temperature resulting from radiofrequency excitation were measured with MR thermometry using a temperature-sensitive contrast agent (TmDOTMA(-)) validated by direct fiber optic temperature measurements. Acquisition of 3D temperature maps of the full phantom with a temperature accuracy better than 0.1°C was achieved with an isotropic resolution of 5 mm and acquisition times of 2-4 minutes. Our results demonstrate the feasibility of constructing anatomically realistic phantoms with complex geometries incorporating the ability to measure accurate temperature maps in the phantom. The anthropomorphic temperature phantom is expected to provide a useful tool for the evaluation of the heating effects of both conventional and parallel transmit pulses and help validate electromagnetic and temperature simulations. © 2014 Wiley Periodicals, Inc.

  12. Puzzles of the dark energy in the universe - phantom

    CERN Document Server

    Dabrowski, Mariusz P

    2014-01-01

    This paper is devoted to some simple approach based on general physics tools to describe the physical properties of a hypothetical particle which can be the source of dark energy in the Universe known as phantom. Phantom is characterized by the fact that it possesses negative momentum and kinetic energy and that it gives large negative pressure which acts as antigravity. We consider phantom harmonic oscillator in comparison to a standard harmonic oscillator. By using the first law of thermodynamics we explain why the energy density of the Universe grows when it is filled with phantom. We also show how the collision of phantom with a standard particle leads to exploration of energy from the former by the latter (i.e. from phantom to the standard) if their masses are different. The most striking of our conclusions is that the collision of phantom and standard particles of the same masses is impossible unless both of them are at rest and suddenly start moving with the opposite velocities and kinetic energies. Th...

  13. Short communication: A printed image quality test phantom for mammography.

    Science.gov (United States)

    Kotre, C J; Porter, D J T

    2005-08-01

    This communication describes a novel design for a mammographic image quality test phantom, the final design of which was produced as a radiographer weekly quality assurance phantom for breast screening and symptomatic mammography. The phantom is based on low contrast test features which are built up by superimposing sheets of Mylar overhead projector transparency, on which the test features are printed using a standard LaserJet printer. The required radiation contrast at mammographic energies is produced by the approximately 50% by weight component of iron oxide (Fe(3)O(4)) present in the toner. An easily replicated design of mammographic image quality phantom based on LaserJet printed test features is described. Approximately 40 of these phantoms were constructed, and these have been used successfully for 5 years in both breast screening and symptomatic mammography. The phantom design offers a performance similar to much more expensive mammographic contrast-detail phantoms, but suffers from the disadvantage that high contrast resolution bar patterns cannot be produced using the standard printing process.

  14. Studies on Phantom Vibration and Ringing Syndrome among Postgraduate Students

    Directory of Open Access Journals (Sweden)

    Atul Kumar Goyal

    2015-03-01

    Full Text Available Phantom vibrations and ringing of mobile phones are prevalent hallucinations in the general population. They might be considered as a normal brain mechanism. The aim of this study was to establish the prevalence of Phantom vibrations and ringing syndrome among students and to assess factors associated it. The survey of 300 postgraduate students belonging to different field of specialization was conducted at Kurukshetra University. 74% of students were found to have both Phantom vibrations and ringing syndrome. Whereas 17% of students felt Phantom vibration exclusively and 4% students face only Phantom ringing syndrome. Both the syndrome occurs more fervent in students who kept their mobile phone in shirt or jean pocket than to who kept mobile in handbag. 75% of students felt vibration or ringing even when the phone is switched off or phone was not in their pocket. Also the frequency of both the syndrome is directly proportional to the duration of mobile phone use and person emotional behavior. Although most of students agree that the Phantom syndrome did not bother them but some students deals with anxiety when they feel symptoms associated with Phantom syndrome. By using mobile phones in proper way, one can avoid these syndromes, or at least can ameliorate the symptoms.

  15. Hubungan Phantom Vibration Syndrome Terhadap Sleep Disorder dan Kondisi Stress

    Directory of Open Access Journals (Sweden)

    Ajeng Yeni Setianingrum

    2017-10-01

    Full Text Available Phantom vibration syndrome is a condition where a person would feel the sensation of vibration of a cell phone as if there were incoming notification but the fact is not. This research investigated the relationship between phantom vibration syndromes, sleep disorder and stress condition. Questionnaires were distributed to 120 participants with age range 18 to 23 years old. Data of participants showed that all of participants using a smart mobile phone and 24% of them have more than one cell phone. Time usage of cell phone is at least 1 hour. 23% of participants using a cell phone for social media activity, followed by 21% related to entertainment (music, video and games. The results showed a positive relationship between phantom vibration syndrome, sleep disorder and stress condition. Insomnia contributed a greater influence on stress condition. However, the phantom vibration syndrome is more directly affecting the sleep apnea compared to insomnia and stress condition. Therefore, the phantom vibration syndrome more affects stress condition indirectly, through sleep disorder (sleep apnea and insomnia. Consequently, phantom vibration syndrome has a strong relationship with stress condition at the time of the phantom vibration syndrome can cause sleep disorder.

  16. The phantom of the night: restless legs syndrome in amputees.

    Science.gov (United States)

    Giummarra, Melita J; Bradshaw, John L

    2010-06-01

    Chronic pain conditions often "mimic" the symptoms of restless legs syndrome (RLS) with worse pain in the evening and upon rest, associated with an urge to move and relief upon movement. We propose that too little has been made of these parallels, with pain conditions resembling RLS being dismissed as mimics. We found, in a large questionnaire study (n=283) on phantom limb perception, a pattern of phantom pain that resembled RLS: amputees with nocturnal phantom pain were more likely to report worse pain upon rest and/or lying down, with an urge to move the phantom and/or walk to relieve their pain, and to experience spontaneous limb movements akin to periodic leg movements of RLS. We present the hypothesis that a model of restless legs syndrome may provide new insights into the mechanisms underlying phantom pain, and lead to new mechanism-based phantom pain treatment. In particular, central changes associated with sensory and motor symptoms of RLS, neuropathy, and dopamine may also be involved in those predisposed to experience phantom pain that mimics the symptoms of RLS. Ultimately, restless legs syndrome may indeed be a pain syndrome, and warrants further investigation in chronic pain populations. .

  17. Cooperative strategies European perspectives

    CERN Document Server

    Killing, J Peter

    1997-01-01

    Cooperative Strategies: European Perspectives is one of three geographically targeted volumes in which the contributors present the most current research on topics such as advances in theories of cooperative strategies, the formation of cooperative alliances, the dynamics of partner relationships, and the role of information and knowledge in cooperative alliances. Blending conceptual insights with empirical analyses, the contributors highlight commonalities and differences across national, cultural, and trade zones. The chapters in this volume are anchored in a wide set of theoretical approaches, conceptual frameworks, and models, illustrating how rich the area of cooperative strategies is for scholarly inquiry.

  18. Dilemmas of partial cooperation.

    Science.gov (United States)

    Stark, Hans-Ulrich

    2010-08-01

    Related to the often applied cooperation models of social dilemmas, we deal with scenarios in which defection dominates cooperation, but an intermediate fraction of cooperators, that is, "partial cooperation," would maximize the overall performance of a group of individuals. Of course, such a solution comes at the expense of cooperators that do not profit from the overall maximum. However, because there are mechanisms accounting for mutual benefits after repeated interactions or through evolutionary mechanisms, such situations can constitute "dilemmas" of partial cooperation. Among the 12 ordinally distinct, symmetrical 2 x 2 games, three (barely considered) variants are correspondents of such dilemmas. Whereas some previous studies investigated particular instances of such games, we here provide the unifying framework and concisely relate it to the broad literature on cooperation in social dilemmas. Complementing our argumentation, we study the evolution of partial cooperation by deriving the respective conditions under which coexistence of cooperators and defectors, that is, partial cooperation, can be a stable outcome of evolutionary dynamics in these scenarios. Finally, we discuss the relevance of such models for research on the large biodiversity and variation in cooperative efforts both in biological and social systems.

  19. Anisotropic phantom to calibrate high-q diffusion MRI methods

    Science.gov (United States)

    Komlosh, M. E.; Benjamini, D.; Barnett, A. S.; Schram, V.; Horkay, F.; Avram, A. V.; Basser, P. J.

    2017-02-01

    A silicon oil-filled glass capillary array is proposed as an anisotropic diffusion MRI phantom. Together with a computational/theoretical pipeline these provide a gold standard for calibrating and validating high-q diffusion MRI experiments. The phantom was used to test high angular resolution diffusion imaging (HARDI) and double pulsed-field gradient (d-PFG) MRI acquisition schemes. MRI-based predictions of microcapillary diameter using both acquisition schemes were compared with results from optical microscopy. This phantom design can be used for quality control and quality assurance purposes and for testing and validating proposed microstructure imaging experiments and the processing pipelines used to analyze them.

  20. Color-matched esophagus phantom for fluorescent imaging

    Science.gov (United States)

    Yang, Chenying; Hou, Vivian; Nelson, Leonard Y.; Seibel, Eric J.

    2013-02-01

    We developed a stable, reproducible three-dimensional optical phantom for the evaluation of a wide-field endoscopic molecular imaging system. This phantom mimicked a human esophagus structure with flexibility to demonstrate body movements. At the same time, realistic visual appearance and diffuse spectral reflectance properties of the tissue were simulated by a color matching methodology. A photostable dye-in-polymer technology was applied to represent biomarker probed "hot-spot" locations. Furthermore, fluorescent target quantification of the phantom was demonstrated using a 1.2mm ultrathin scanning fiber endoscope with concurrent fluorescence-reflectance imaging.

  1. Neutron Field Measurements in Phantom with Foil Activation Methods.

    Science.gov (United States)

    1986-11-29

    jI25 Ii III uumu ullli~ S....- - Lb - w * .qJ’ AD-A 192 122 ulJ. IL (pj DNA-TR-87- 10 N EUTRON FIELD MEASUREMENTS IN PHANTOM WITH FOIL ACTIVATION...SAND II Measurements in Phantom 6 4 The 5-Foil Neutron Dosimetry Method 29 5 Comparison of SAND II and Simple 5-Foil Dosimetry Method 34 6 Thermal ...quite reasonable. The monkey phantom spectrum differs from the NBS U-235 fission spectrum in that the former has a I/E tail plus thermal -neutron peak

  2. Prevalence and Clinical Features of Phantom Breast Syndrome: Literature Review

    Directory of Open Access Journals (Sweden)

    Dilek Aygin

    2017-03-01

    Findings:In the samples of these 11 studies; there were 627 patients who had mastectomy and 7.8% of them (49 patients were diagnosed with phantom breast syndrome, 65.8% (413 patients had phantom breast sensation and 6.7% (42 patients had phantom breast pain. Conclusion:It is needed to define certain standards in the assessment of PBS, professional meetings should be done for the treatment and care of patients with PBS. In addition, more randomized controlled studies are needed in this subject. [J Contemp Med 2017; 7(1.000: 97-106

  3. Phantom jam avoidance through in-car speed advice

    OpenAIRE

    Suijs, L.C.W.; Wismans, L.J.J.; Krol, L.; Berkum, van, E.C.

    2015-01-01

    The existence of phantom jams can be explained following the definition of Kerner & Konhäuser (1993) who state that a phantom jam occurs without the existence of a physical bottleneck and is caused by the imperfect driving style of road users under metastable traffic conditions. In order to prevent a phantom jams to occur, one can either focus on the cause of the perturbation, or on the metastability of the traffic flow. Previous studies have shown that the use of dynamic speed limits, displa...

  4. Computational hybrid anthropometric paediatric phantom library for internal radiation dosimetry

    DEFF Research Database (Denmark)

    Xie, Tianwu; Kuster, Niels; Zaidi, Habib

    2017-01-01

    covering statistical distributions of body morphometry in the paediatric population. The paediatric phantoms of the Virtual Population Series (IT'IS Foundation, Switzerland) were modified to match target anthropometric parameters, including body mass, body length, standing height and sitting height...... to create 1100 female and male phantoms with 10th, 25th, 50th, 75th and 90th body morphometries. Evaluation was performed qualitatively using 3D visualization and quantitatively by analysing internal organ masses. Overall, the newly generated phantoms appear very reasonable and representative of the main...

  5. The Global Dimension of Water Governance: Why the River Basin Approach Is No Longer Sufficient and Why Cooperative Action at Global Level Is Needed

    Directory of Open Access Journals (Sweden)

    Arjen Y. Hoekstra

    2010-12-01

    Full Text Available When water problems extend beyond the borders of local communities, the river basin is generally seen as the most appropriate unit for analysis, planning, and institutional arrangements. In this paper it is argued that addressing water problems at the river basin level is not always sufficient. Many of today’s seemingly local water issues carry a (subcontinental or even global dimension, which urges for a governance approach that comprises institutional arrangements at a level beyond that of the river basin. This paper examines a number of arguments for the thesis that good water governance requires a global approach complementary to the river basin approach. Subsequently, it identifies four major issues to be addressed at global scale: Efficiency, equity, sustainability and security of water supply in a globalised world. Finally, the paper raises the question of what kind of institutional arrangements could be developed to cope with the global dimension of water issues. A few possible directions are explored, ranging from an international protocol on full-cost water pricing and a water label for water-intensive products to the implementation of water footprint quotas and the water-neutral concept.

  6. On Wormholes supported by phantom energy

    CERN Document Server

    González, J A; Montelongo-Garcia, N; Zannias, T

    2009-01-01

    By a combination of analytical and numerical techniques, we demonstrate the existence of spherical, asymptotically flat traversable wormholes supported by exotic matter whose stress tensor relative to the orthonormal frame of Killing observers takes the form of a perfect fluid possessing anisotropic pressures and subject to linear equations of state: $\\tau=\\lambda\\rho c^{2}$, $P=\\mu\\rho c^{2}$. We show that there exists a four parameter family of asymptotically flat spherical wormholes parametrized by the area of the throat A(0), the gradient $\\Lambda(0)$ of the red shift factor evaluated at the throat as well as the values of $(\\lambda, \\mu)$. The latter are subject to restrictions: $\\lambda>1$ and $2\\mu>\\lambda$ or $\\lambda<0$ and $2\\mu<-|\\lambda|$. For particular values of $(\\lambda, \\mu)$, the stress tensor may be interpreted as representing a phantom configuration, while for other values represents exotic matter. All solutions have the property that the two asymptotically flat ends posses finite AD...

  7. Cosmological perturbations on the Phantom brane

    CERN Document Server

    Bag, Satadru; Shtanov, Yuri; Sahni, Varun

    2016-01-01

    We obtain a closed system of equations for scalar perturbations in a multi-component braneworld. Our braneworld possesses a phantom-like equation of state at late times, $w_{\\rm eff} < -1$, but no big-rip future singularity. In addition to matter and radiation, the braneworld possesses a new effective degree of freedom - the 'Weyl fluid' or 'dark radiation'. Setting initial conditions on super-Hubble spatial scales at the epoch of radiation domination, we evolve perturbations of radiation, pressureless matter and the Weyl fluid until the present epoch. We observe a gradual decrease in the amplitude of the Weyl-fluid perturbations after Hubble-radius crossing, which results in a negligible effect of the Weyl fluid on the evolution of matter perturbations on spatial scales relevant for structure formation. Consequently, the quasi-static approximation of Koyama and Maartens provides a good fit to the exact results during the matter-dominated epoch. We find that the late-time growth of density perturbations on...

  8. Dynamic eye phantom for retinal oximetry measurements

    Science.gov (United States)

    Lemaillet, Paul; Ramella-Roman, Jessica C.

    2009-11-01

    Measurements of oxygen saturation and flow in the retina can yield information about eye health and the onset of eye pathologies such as diabetic retinopathy. Recently, we developed a multiaperture camera that uses the division of the retinal image into several wavelength-sensitive subimages to compute retinal oxygen saturation. The calibration of such instruments is particularly difficult due to the layered structure of the eye and the lack of alternative measurement techniques. For this purpose, we realize an in vitro model of the human eye composed of a lens, the retina vessel, and three layers: the choroid, the retinal pigmented epithelium, and the sclera. The retinal vessel is modeled with a microtube connected to a micropump and a hemoglobin reservoir in a closed circulatory system. Hemoglobin oxygenation in the vessel could be altered using a reversible fuel cell. The sclera is represented by a Spectralon slab. The optical properties of the other layers are mimicked using titanium dioxide as a scatterer, ink as an absorber, and epoxy as a supporting structure. The optical thickness of each layer of the eye phantom is matched to each respective eye layer.

  9. Interlaboratory comparison of backscatter coefficient estimates for tissue-mimicking phantoms.

    Science.gov (United States)

    Anderson, Janelle J; Herd, Maria-Teresa; King, Michael R; Haak, Alexander; Hafez, Zachary T; Song, Jun; Oelze, Michael L; Madsen, Ernest L; Zagzebski, James A; O'Brien, William D; Hall, Timothy J

    2010-01-01

    Ultrasonic backscatter is useful for characterizing tissues and several groups have reported methods for estimating backscattering properties. Previous interlaboratory comparisons have been made to test the ability to accurately estimate the backscatter coefficient (BSC) by different laboratories around the world. Results of these comparisons showed variability in BSC estimates but were acquired only for a relatively narrow frequency range, and, most importantly, lacked reference to any independent predictions from scattering theory. The goal of this study was to compare Faran-scattering-theory predictions with cooperatively-measured backscatter coefficients for low-attenuating and tissue-like attenuating phantoms containing glass sphere scatterers of different sizes for which BSCs can independently be predicted. Ultrasonic backscatter measurementswere made for frequencies from 1 to 12 MHz. Backscatter coefficients were estimated using two different planar-reflector techniques at two laboratories for two groups of phantoms. Excellent agreement was observed between BSC estimates from both laboratories. In addition, good agreement with the predictions of Faran's theory was obtained, with average fractional (bias) errors ranging from 8-14%. This interlaboratory comparison demonstrates the ability to accurately estimate parameters derived from the BSC, including an effective scatterer size and the acoustic concentration, both of which may prove useful for diagnostic applications of ultrasound tissue characterization.

  10. Suggested guidelines for treatment of phantom limb pain.

    Science.gov (United States)

    Sherman, R A; Tippens, J K

    1982-12-01

    Eighty to ninety percent of amputees have been shown to suffer significant amounts of phantom limb pain in contrast to the widely accepted level of about 5%. Surveys of the literature, of physicians actively treating phantom pain, and of over 3,000 American veteran amputees have shown that most of the usual treatments are not efficacious when followups of a year or more are done. A diagnostic and therapeutic schemata is presented, which incorporates the above surveys, research, and clinical experience into a unified approach optimizing the few treatments showing a reasonable hope of long term success. Every effort is made to identify the source of pain being referred into the phantom. Stump, back, prosthetic, and other physical problems are corrected prior to initiation of other treatments, including EMG or temperature feedback from the stump, sympathetic system alteration, modulation of anxiety and depression, TENS, and ultrasound. Key indexing terms: phantom pain, treatment, amputees, referred pain. Copyright 2013, SLACK Incorporated.

  11. Thermodynamics in $F(R)$ gravity with phantom crossing

    CERN Document Server

    Bamba, Kazuharu

    2009-01-01

    We study thermodynamics of the apparent horizon in $F(R)$ gravity. In particular, we demonstrate that a $F(R)$ gravity model with realizing a crossing of the phantom divide can satisfy the second law of thermodynamics.

  12. Phantom crossing in viable $f(R)$ theories

    CERN Document Server

    Bamba, Kazuharu; Lee, Chung-Chi

    2011-01-01

    We review the equation of state for dark energy in modified gravity theories. In particular, we summarize the generic feature of the phantom divide crossing in the past and future in viable $f(R)$ gravity models.

  13. Fabrication and characterization of phantoms made of polydimethylsiloxane (PDMS)

    Science.gov (United States)

    Villanueva-Luna, A. E.; Santiago-Alvarado, A.; Castro-Ramos, J.; Licona-Moran, B.; Vazquez-Montiel, S.; Flores-Gil, A.; Delgado-Atencio, J. A.

    2011-03-01

    The transparent elastomer Polydimethylsiloxane (PDMS) Sylgard 184 is increasingly used in optical applications, as in the manufacture of microlens, waveguides (optical fibers) and to elaborated phantoms (simulator of biological tissue); The wide range of applications is due to its excellent physic-chemical properties, its low cost, easy operation and null toxicity. This paper describes the manufacturing process and physic-chemical characterization of Phantoms prepared with PDMS as grid and doped with some elements present as Gliceryl, ink, glucose 10% and melanin provided by sigma aldrich. We made phantoms with different concentrations and elements; we measured their profiles, and thicknesses. Finally, we obtained their Raman Spectra. We present the experimental results obtained of the physic-chemical parameters of the phantoms and the conclusions.

  14. [Phantoms for the collection of genital secretions in stallions].

    Science.gov (United States)

    Klug, E; Brinkhoff, D; Flüge, A; Scherbarth, R; Essich, G; Kienzler, M

    1977-10-01

    Practical experiences of the phantom method for collection of genital secretions from stallions are reported. Taking a phantom used in the Richard-Götze-Haus Tierärztliche Hochschule Hannover as a prototype two further models slightly modified have been constructed, baring a flat hollow in the right side of the caudal phantom body for manual inserting of the Artificial Vagina. These three models fulfill four important conditions for routine use: (1) sufficient sexual attractivity for the stallions; 80-85% successful collections of presecretions out of a total of 1050 using the dummy and 70% successful semen collections from more than 240 in total; (2) solid and resistant construction; (3) easy cleaning and desinfection of the surface of the phantom to get representative samples; (4) firm installation on a hygienic floor.

  15. Phantom dark ghost in Einstein-Cartan gravity

    Science.gov (United States)

    Chang, Yu-Chiao; Bouhmadi-López, Mariam; Chen, Pisin

    2017-05-01

    A class of dynamical dark energy models is constructed through an extended version of fermion fields corresponding to phantom dark ghost spinors, which are spin 1/2 with mass dimension 1. We find that if these spinors interact with torsion fields in a homogeneous and isotropic universe, then it does not imply any future dark energy singularity or any abrupt event, though the fermion has a negative kinetic energy. In fact, the equation of state of this dark energy model will asymptotically approach the value w=-1 from above without crossing the phantom divide and inducing therefore a de Sitter state. Consequently, we expect the model to be stable because no real phantom fields will be created. At late time, the torsion fields will vanish as the corresponding phantom dark ghost spinors dilute. As would be expected, intuitively, this result is unaffected by the presence of cold dark matter although the proof is not as straightforward as in general relativity.

  16. Bioassay Phantoms Using Medical Images and Computer Aided Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Dr. X. Geroge Xu

    2011-01-28

    A radiation bioassay program relies on a set of standard human phantoms to calibrate and assess radioactivity levels inside a human body for radiation protection and nuclear medicine imaging purposes. However, the methodologies in the development and application of anthropomorphic phantoms, both physical and computational, had mostly remained the same for the past 40 years. We herein propose a 3-year research project to develop medical image-based physical and computational phantoms specifically for radiation bioassay applications involving internally deposited radionuclides. The broad, long-term objective of this research was to set the foundation for a systematic paradigm shift away from the anatomically crude phantoms in existence today to realistic and ultimately individual-specific bioassay methodologies. This long-term objective is expected to impact all areas of radiation bioassay involving nuclear power plants, U.S. DOE laboratories, and nuclear medicine clinics.

  17. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  18. A feasibility study of Dynamic Phantom scanner for quality assurance of photon beam profiles at various gantry angles.

    Science.gov (United States)

    Zhang, Yunkai; Hsi, Wen C; Chu, James C H; Bernard, Damian B; Abrams, Ross A

    2005-01-01

    The effect of gantry rotation on beam profiles of photon and electron beams is an important issue in quality assurance for radiotherapy. To address variations in the profiles of photon and electron beams at different gantry angles, a Dynamic Phantom scanner composed of a 20 x 12 x 6 cm3 scanning Lucite block was designed as a cross-beam-profile scanner. To our knowledge, differences between scanned profiles acquired at different gantry angles with a small size Lucite block and those acquired a full-size (60 x 60 x 50 cm3) water phantom have not been previously investigated. We therefore performed a feasibility study for a first prototype Dynamic Phantom scanner without a gantry attachment mount. Radiation beams from a Varian LINAC 21EX and 2100C were used. Photon beams (6 MV and 18 MV) were shaped by either collimator jaws or a Varian 120 Multileaf (MLC) collimator, and electron beams (6 MeV, 12 MeV, and 20 MeV) were shaped by a treatment cone. To investigate the effect on profiles by using a Lucite block, a quantitative comparison of scanned profiles with the Dynamic Phantom and a full-size water phantom was first performed at a 0 degrees gantry angle for both photon and electron beams. For photon beam profiles defined by jaws at 1.0 cm and 5.0 cm depths of Lucite (i.e., at 1.1 cm and 5.7 cm depth of water), a good agreement (less than 1% variation) inside the field edge was observed between profiles scanned with the Dynamic Phantom and with a water phantom. The use of Lucite in the Dynamic Phantom resulted in reduced penumbra width (about 0.5 mm out of 5 mm to 8mm) and reduced (1% to 2%) scatter dose beyond the field edges for both 6 MV and 18 MV beams, compared with the water phantom scanner. For profiles of the MLC-shaped 6 MV photon beam, a similar agreement was observed. For profiles of electron beams scanned at 2.9 cm depth of Lucite (i.e., at 3.3 cm depth of water), larger disagreements in profiles (3% to 4%) and penumbra width (3 mm to 4 mm out of 12 mm

  19. Evaluation of water resources system vulnerability based on co-operative co-evolutionary genetic algorithm and projection pursuit model under the DPSIR framework

    Science.gov (United States)

    Zhao, Y.; Su, X. H.; Wang, M. H.; Li, Z. Y.; Li, E. K.; Xu, X.

    2017-08-01

    Water resources vulnerability control management is essential because it is related to the benign evolution of socio-economic, environmental and water resources system. Research on water resources system vulnerability is helpful to realization of water resources sustainable utilization. In this study, the DPSIR framework of driving forces-pressure–state–impact-response was adopted to construct the evaluation index system of water resources system vulnerability. Then the co-evolutionary genetic algorithm and projection pursuit were used to establish evaluation model of water resources system vulnerability. Tengzhou City in Shandong Province was selected as a study area. The system vulnerability was analyzed in terms of driving forces, pressure, state, impact and response on the basis of the projection value calculated by the model. The results show that the five components all belong to vulnerability Grade II, the vulnerability degree of impact and state were higher than other components due to the fierce imbalance in supply-demand and the unsatisfied condition of water resources utilization. It is indicated that the influence of high speed socio-economic development and the overuse of the pesticides have already disturbed the benign development of water environment to some extents. While the indexes in response represented lower vulnerability degree than the other components. The results of the evaluation model are coincident with the status of water resources system in the study area, which indicates that the model is feasible and effective.

  20. New developments in eye models with retina tissue phantoms for ophthalmic optical coherence tomography

    Science.gov (United States)

    Rowe, T. Scott; Zawadzki, Robert J.

    2012-03-01

    We document our latest work in developing eye models with solid-state retinal tissue phantoms designed for demonstrating, validating and comparing ophthalmic Optical Coherence Tomography (OCT) instruments. Eye models with retina tissue phantoms can serve a variety of purposes, including demonstrating OCT functionality and performance in both the clinic and exhibit hall, validating retina layer thickness measurements from different commercial OCT instruments and as an aide for the R&D engineer and field service technician in the development and repair of instruments, respectively. The ideal eye model for OCT, the optical cross-sectional imaging modality, would have a volumetric morphology and scattering and absorption properties similar to that of normal human retina. These include a multi-layered structure of equivalent thickness to nominal human retina layers, a foveal pit that can be used to orient the image, and a RPE/OS and choroid like layers to demonstrate the depth penetration of the OCT system. A solid state tissue phantom relieves the user of constant cleaning and maintenance associated with the more common water bath model eyes. Novel processes12 have been developed to create retinal layers model that closely mimic the reflectance and scattering coefficients of the real layers of the retina, as imaged by spectral bandwidth of OCT.

  1. Viewing the effective k-space coverage of MR images: phantom experiments with fast Fourier transform.

    Science.gov (United States)

    Menke, Jan; Helms, Gunther; Larsen, Jörg

    2010-01-01

    The purpose of this experimental study was to evaluate whether the effective k-space coverage of MR images can in principle be viewed after multidimensional Fourier transform back to k-space. A water-soaked sponge phantom providing homogeneous k-space pattern was imaged with different standard MR sequences, utilizing elliptic acquisitions, partial-Fourier acquisitions and elliptic filtering as imaging examples. The resulting MR images were Fourier-transformed to the spatial frequency domain (the k-space) to visualize their effective k-space coverage. These frequency domain images are named "backtransformed k-space images." For a quantitative assessment, the sponge phantom was imaged with three-dimensional partial-Fourier sequences while varying the partial acquisition parameters in slice and phase direction. By linear regression analysis, the k-space coverage as expected from the sequence menu parameters was compared to the effective k-space coverage as observed in the backtransformed k-space images. The k-space coverage of elliptic and partial-Fourier acquisitions became visible in the backtransformed k-space images, as well as the effect of elliptic filtering. The expected and the observed k-space coverage showed a highly significant correlation (r=.99, PFourier-transforming MR images of a sponge phantom back to k-space. This method could be used for several purposes including sequence parameter optimization, basic imaging research, and to enhance a visual understanding of k-space, especially in three-dimensional MR imaging.

  2. Crossing of Phantom Divide in $F(R)$ Gravity

    CERN Document Server

    Bamba, Kazuharu; Nojiri, Shin'ichi; Odintsov, Sergei D

    2010-01-01

    An explicit model of $F(R)$ gravity with realizing a crossing of the phantom divide is reconstructed. In particular, it is shown that the Big Rip singularity may appear in the reconstructed model of $F(R)$ gravity. Such a Big Rip singularity could be avoided by adding $R^2$ term or non-singular viable $F(R)$ theory to the model because phantom behavior becomes transient.

  3. Prevalent hallucinations during medical internships: phantom vibration and ringing syndromes.

    Directory of Open Access Journals (Sweden)

    Yu-Hsuan Lin

    Full Text Available BACKGROUND: Phantom vibration syndrome is a type of hallucination reported among mobile phone users in the general population. Another similar perception, phantom ringing syndrome, has not been previously described in the medical literature. METHODS: A prospective longitudinal study of 74 medical interns (46 males, 28 females; mean age, 24.8±1.2 years was conducted using repeated investigations of the prevalence and associated factors of phantom vibration and ringing. The accompanying symptoms of anxiety and depression were evaluated with the Beck Anxiety and Depression Inventories before the internship began, and again at the third, sixth, and twelfth internship months, and two weeks after the internship ended. RESULTS: The baseline prevalence of phantom vibration was 78.1%, which increased to 95.9% and 93.2% in the third and sixth internship months. The prevalence returned to 80.8% at the twelfth month and decreased to 50.0% 2 weeks after the internship ended. The baseline prevalence of phantom ringing was 27.4%, which increased to 84.9%, 87.7%, and 86.3% in the third, sixth, and twelfth internship months, respectively. This returned to 54.2% two weeks after the internship ended. The anxiety and depression scores also increased during the internship, and returned to baseline two weeks after the internship. There was no significant correlation between phantom vibration/ringing and symptoms of anxiety or depression. The incidence of both phantom vibration and ringing syndromes significantly increased during the internship, and subsequent recovery. CONCLUSION: This study suggests that phantom vibration and ringing might be entities that are independent of anxiety or depression during evaluation of stress-associated experiences during medical internships.

  4. Caracterización de Phantoms por ultrasonidos

    OpenAIRE

    2012-01-01

    El principal objetivo es el desarrollo de sistemas ultrasónicos que permitan medir con precisión distribuciones de los principales parámetros acústicos que caracterizan el comportamiento de los "Tejidos equivalentes" (Phantoms), empleados en laboratorio con el fin de identificar entre tejidos sano y enfermo mediante los ultrasonidos Ortí Anglés, C. (2012). Caracterización de Phantoms por ultrasonidos. http://hdl.handle.net/10251/17787. Archivo delegado

  5. Computational hybrid anthropometric paediatric phantom library for internal radiation dosimetry

    Science.gov (United States)

    Xie, Tianwu; Kuster, Niels; Zaidi, Habib

    2017-04-01

    Hybrid computational phantoms combine voxel-based and simplified equation-based modelling approaches to provide unique advantages and more realism for the construction of anthropomorphic models. In this work, a methodology and C++ code are developed to generate hybrid computational phantoms covering statistical distributions of body morphometry in the paediatric population. The paediatric phantoms of the Virtual Population Series (IT’IS Foundation, Switzerland) were modified to match target anthropometric parameters, including body mass, body length, standing height and sitting height/stature ratio, determined from reference databases of the National Centre for Health Statistics and the National Health and Nutrition Examination Survey. The phantoms were selected as representative anchor phantoms for the newborn, 1, 2, 5, 10 and 15 years-old children, and were subsequently remodelled to create 1100 female and male phantoms with 10th, 25th, 50th, 75th and 90th body morphometries. Evaluation was performed qualitatively using 3D visualization and quantitatively by analysing internal organ masses. Overall, the newly generated phantoms appear very reasonable and representative of the main characteristics of the paediatric population at various ages and for different genders, body sizes and sitting stature ratios. The mass of internal organs increases with height and body mass. The comparison of organ masses of the heart, kidney, liver, lung and spleen with published autopsy and ICRP reference data for children demonstrated that they follow the same trend when correlated with age. The constructed hybrid computational phantom library opens up the prospect of comprehensive radiation dosimetry calculations and risk assessment for the paediatric population of different age groups and diverse anthropometric parameters.

  6. [Psychotherapies for the Treatment of Phantom Limb Pain].

    Science.gov (United States)

    Cárdenas, Katherine; Aranda, Mariana

    The phantom limb pain has been described as a condition in which patients experience a feeling of itching, spasm or pain in a limb or body part that has been previously amputated. Such pain can be induced by a conflict between the representation of the visual and proprioceptive feedback of the previously healthy limb. The phantom limb pain occurs in at least 42 to 90% of amputees. Regular drug treatment of phantom limb pain is almost never effective. A systematic review of the literature was conducted in Medline and Cochrane using the MESH terms "phantom limb pain" and "psychotherapy", published in the last 10 years, in English and Spanish, finding 49 items. After reviewing the abstracts, 25 articles were excluded for not being related to the objective of the research. Additionally cross references of included articles and literature were reviewed. To describe the psychotherapies used in the management of phantom limb pain, their effectiveness and clinical application reported in the literature. The mechanisms underlying phantom limb pain were initially explained, as were the published studies on the usefulness of some psychotherapies such as mirror visual feedback and immersive virtual reality, visual imagery, desensitization and reprocessing eye movements and hypnosis. The phantom limb pain is a complex syndrome that requires pharmacological and psychotherapeutic intervention. The psychotherapies that have been used the most as adjuvants in the treatment of phantom limb pain are mirror visual feedback, desensitization and reprocessing eye movements, imagery and hypnosis. Studies with more representative samples, specifically randomized trials are required. Copyright © 2016 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  7. Possible association between phantom vibration syndrome and occupational burnout

    OpenAIRE

    Chen CP; Wu CC; Chang LR; Lin YH

    2014-01-01

    Chao-Pen Chen,1 Chi-Cheng Wu,2 Li-Ren Chang,3 Yu-Hsuan Lin4 1Department of Education, National Taiwan University Hospital, 2Department of Family Medicine, Min-Sheng General Hospital, Taoyuan City, 3Department of Psychiatry, National Taiwan University, College of Medicine, 4Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan Background: Phantom vibration syndrome (PVS) and phantom ringing syndrome (PRS) occur in many cell phone users. Previous studies have indicated an ...

  8. Manufacture of polystyrene phantoms for beta radiation dosimetry; Confeccao de objetos simuladores em poliestireno para dosimetria da radiacao beta

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Marcia L.; Caldas, Linda V.E. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: mlolivei@ipen.br; lcaldas@ipen.br

    2005-07-01

    {sup 90}Sr+{sup 90}Y beta radiation sources should be specified in terms of absorbed dose rate to water, following recent international recommendations. Due to the high dose gradients near source surfaces, the accurate determination of the distances involved in calibration procedures is extremely important, since the calibration of these sources is performed at 1 mm from their surfaces, in their central symmetry axis. To guarantee the adequate and reproducible positioning between the source during the calibration procedure and the radiation detector, the use of solid phantoms is convenient. Recent papers show that the most appropriate material as water substitute for beta radiation is the polystyrene. In this work, polystyrene phantoms were manufactured for thermoluminescent samples of LiF, CaF{sub 2}:Dy and CaF{sub 2}:Mn. A {sup 90}Sr+{sup 90}Y plane applicator was utilized to irradiate the samples. The maximum sample response variation was equal to: 4.9% for LiF; 3.7% for CaF{sub 2}:Dy; and 3.3% for CaF{sub 2}:Mn. The obtained results show the feasibility of the use of polystyrene phantoms in beta radiation dosimetry. The low cost phantoms guaranteed the reproducible positioning between the {sup 90}Sr+{sup 90}Y source and the samples, as desired. (author)

  9. Fabrication of rigid and flexible refractive-index-matched flow phantoms for flow visualisation and optical flow measurements

    Science.gov (United States)

    Geoghegan, P. H.; Buchmann, N. A.; Spence, C. J. T.; Moore, S.; Jermy, M.

    2012-05-01

    A method for the construction of both rigid and compliant (flexible) transparent flow phantoms of biological flow structures, suitable for PIV and other optical flow methods with refractive-index-matched working fluid is described in detail. Methods for matching the in vivo compliance and elastic wave propagation wavelength are presented. The manipulation of MRI and CT scan data through an investment casting mould is described. A method for the casting of bubble-free phantoms in silicone elastomer is given. The method is applied to fabricate flexible phantoms of the carotid artery (with and without stenosis), the carotid artery bifurcation (idealised and patient-specific) and the human upper airway (nasal cavity). The fidelity of the phantoms to the original scan data is measured, and it is shown that the cross-sectional error is less than 5% for phantoms of simple shape but up to 16% for complex cross-sectional shapes such as the nasal cavity. This error is mainly due to the application of a PVA coating to the inner mould and can be reduced by shrinking the digital model. Sixteen per cent variation in area is less than the natural patient to patient variation of the physiological geometries. The compliance of the phantom walls is controlled within physiologically realistic ranges, by choice of the wall thickness, transmural pressure and Young's modulus of the elastomer. Data for the dependence of Young's modulus on curing temperature are given for Sylgard 184. Data for the temperature dependence of density, viscosity and refractive index of the refractive-index-matched working liquid (i.e. water-glycerol mixtures) are also presented.

  10. Phantom Energy Accretion by a Stringy Charged Black Hole

    Institute of Scientific and Technical Information of China (English)

    M.Sharif; G.Abbas

    2012-01-01

    We investigate the dynamical behavior of phantom energy near a stringy magnetically charged black hole. For this purpose, we derive equations of motion for steady-state spherically symmetric Row of phantom energy onto the stringy magnetically charged black hole. It is found that phantom energy accreting onto a black hole decreases its mass. Further, the location of the critical points of accretion is explored, which yields a mass to charge ratio. This ratio implies that accretion process cannot transform a black hole into an extremal black hole or a naked singularity, hence cosmic censorship hypothesis remains valid here.%We investigate the dynamical behavior of phantom energy near a stringy magnetically charged black hole.For this purpose,we derive equations of motion for steady-state spherically symmetric flow of phantom energy onto the stringy magnetically charged black hole.It is found that phantom energy accreting onto a black hole decreases its mass.Further,the location of the critical points of accretion is explored,which yields a mass to charge ratio.This ratio implies that accretion process cannot transform a black hole into an extremal black hole or a naked singularity,hence cosmic censorship hypothesis remains valid here.

  11. Use of optical skin phantoms for calibration of dermatological lasers

    Science.gov (United States)

    Wróbel, M. S.; Sekowska, A.; Marchwiński, M.; Galla, S.; Cenian, A.

    2016-09-01

    A wide range of dermatological diseases can be efficiently treated using laser heating. Nevertheless, before the new laser is introduced into clinical practice, its parameters and ability to interact with human skin have to be carefully examined. In order to do that optical skin phantoms can be used. Such phantoms closely imitate the scattering and absorption properties of real human skin tissue along with its thermal properties, such as capacitance and conductivity specific heat. We have fabricated a range of optical tissue phantoms based on polyvinylchloride-plastisol PVC-P with varying optical properties, including the absorption, scattering and density of the matrix material. We have utilized a pre-clinical dermatological laser system with a 975 nm diode laser module. A range of laser settings were tested, such as laser pulse duration, laser power and number of pulses. We have studied laser irradiation efficiency on fabricated optical tissue phantoms. Measurements of the temporal and spatial temperature distribution on the phantoms' surface were performed using thermographic imaging. The comparison of results between tissues' and phantoms' optical and thermal response prove that they can be used for approximate evaluation of laser heating efficiency. This study presents a viable approach for calibration of dermatological lasers which can be utilized in practice.

  12. Design and fabrication of a solid simplified head phantom

    Science.gov (United States)

    Tanikawa, Yukari; Imai, Daigo; Mizuno, Sho; Maki, Hiroshi; Shinozaki, Osamu; Yamada, Yukio

    1997-08-01

    Optical tomography aims to image the distribution of optical properties in human bodies by measuring transmitted light at skin surfaces. Pervious calculations and experiments have been mainly performed on phantoms with simple geometries such as slabs and cylinders, but for optical tomography it is inevitable to fully understand light propagation through and perform experiments using phantoms with complicated structures in three dimensions. Therefore, we need stable and realistic solid phantoms for experimental studies toward the goal of optical tomography. In this study, we have fabricated two types of solid phantoms which optically and anatomically simulate human heads. One has a shape and structures of a part of human head above eye plane, and the other has a more simplified shape of hemisphere. These phantoms consisted of five layers which corresponded to five tissue types in human head; i.e., skin, skull, clear CSF layer, gray matter and white matter. Size and optical properties were given according to those of human neonatal head. After taking original shapes from MRI images, prototypes of five layers were fabricated by a rapid prototyping based photolithography. Epoxy resin with titanium oxide particles as scatterers and green dye as absorber was cast into the molds of the prototypes to make optical phantoms. Absorbers simulating inhomogeneities were also embedded.

  13. Sensitivity evaluation of DSA-based parametric imaging using Doppler ultrasound in neurovascular phantoms

    Science.gov (United States)

    Balasubramoniam, A.; Bednarek, D. R.; Rudin, S.; Ionita, C. N.

    2016-03-01

    An evaluation of the relation between parametric imaging results obtained from Digital Subtraction Angiography (DSA) images and blood-flow velocity measured using Doppler ultrasound in patient-specific neurovascular phantoms is provided. A silicone neurovascular phantom containing internal carotid artery, middle cerebral artery and anterior communicating artery was embedded in a tissue equivalent gel. The gel prevented movement of the vessels when blood mimicking fluid was pumped through it to obtain Colour Doppler images. The phantom was connected to a peristaltic pump, simulating physiological flow conditions. To obtain the parametric images, water was pumped through the phantom at various flow rates (100, 120 and 160 ml/min) and 10 ml contrast boluses were injected. DSA images were obtained at 10 frames/sec from the Toshiba C-arm and DSA image sequences were input into LabVIEW software to get parametric maps from time-density curves. The parametric maps were compared with velocities determined by Doppler ultrasound at the internal carotid artery. The velocities measured by the Doppler ultrasound were 38, 48 and 65 cm/s for flow rates of 100, 120 and 160 ml/min, respectively. For the 20% increase in flow rate, the percentage change of blood velocity measured by Doppler ultrasound was 26.3%. Correspondingly, there was a 20% decrease of Bolus Arrival Time (BAT) and 14.3% decrease of Mean Transit Time (MTT), showing strong inverse correlation with Doppler measured velocity. The parametric imaging parameters are quite sensitive to velocity changes and are well correlated to the velocities measured by Doppler ultrasound.

  14. Compound analysis of gallstones using dual energy computed tomography-Results in a phantom model

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Ralf W., E-mail: ralfwbauer@aol.co [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany); Schulz, Julian R., E-mail: julian.schulz@t-online.d [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany); Zedler, Barbara, E-mail: zedler@em.uni-frankfurt.d [Department of Forensic Medicine, Clinic of the Goethe University Frankfurt, Kennedyallee 104, 60596 Frankfurt (Germany); Graf, Thomas G., E-mail: thomas.gt.graf@siemens.co [Siemens AG Healthcare Sector, Computed Tomography, Physics and Applications, Siemensstrasse 1, 91313 Forchheim (Germany); Vogl, Thomas J., E-mail: t.vogl@em.uni-frankfurt.d [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University Frankfurt, Theodor-Stern-Kai 7, 60596 Frankfurt (Germany)

    2010-07-15

    Purpose: The potential of dual energy computed tomography (DECT) for the analysis of gallstone compounds was investigated. The main goal was to find parameters, that can reliably define high percentage (>70%) cholesterol stones without calcium components. Materials and methods: 35 gallstones were analyzed with DECT using a phantom model. Stone samples were put into specimen containers filled with formalin. Containers were put into a water-filled cylindrical acrylic glass phantom. DECT scans were performed using a tube voltage/current of 140 kV/83 mAs (tube A) and 80 kV/340 mAs (tube B). ROI-measurements to determine CT attenuation of each sector of the stones that had different appearance on the CT images were performed. Finally, semi-quantitative infrared spectroscopy (FTIR) of these sectors was performed for chemical analysis. Results: ROI-measurements were performed in 45 different sectors in 35 gallstones. Sectors containing >70% of cholesterol and no calcium component (n = 20) on FTIR could be identified with 95% sensitivity and 100% specificity on DECT. These sectors showed typical attenuation of -8 {+-} 4 HU at 80 kV and +22 {+-} 3 HU at 140 kV. Even the presence of a small calcium component (<10%) hindered the reliable identification of cholesterol components as such. Conclusion: Dual energy CT allows for reliable identification of gallstones containing a high percentage of cholesterol and no calcium component in this pre-clinical phantom model. Results from in vivo or anthropomorphic phantom trials will have to confirm these results. This may enable the identification of patients eligible for non-surgical treatment options in the future.

  15. A phantom study on the positioning accuracy of the Novalis Body system.

    Science.gov (United States)

    Yan, Hui; Yin, Fang-Fang; Kim, Jae Ho

    2003-12-01

    A phantom study was conducted to investigate inherent positioning accuracy of an image-guided patient positioning system-the Novalis Body system for three-dimensional (3-D) conformal radiotherapy. This positioning system consists of two infrared (IR) cameras and one video camera and two kV x-ray imaging devices. The initial patient setup was guided by the IR camera system and the target localization was accomplished using the kV x-ray imaging system. In this study, the IR marker shift and phantom rotation were simulated and their effects on the positioning accuracy were examined by a Rando phantom. The effects of CT slice thickness and treatment sites on the positioning accuracy were tested. In addition, the internal target shift was simulated and its effect on the positioning accuracy was examined by a water tank. With the application of the Novalis Body system, the positioning error of the planned isocenter was significantly reduced. The experimental results with the simulated IR marker shifts indicated that the positioning errors of the planned isocenter were 0.6 +/- 0.3, 0.5 +/- 0.2, and 0.7 +/- 0.2 mm along the lateral, longitudinal, and vertical axes, respectively. The experimental results with the simulated phantom rotations indicated that the positioning errors of the planned isocenter were 0.6 +/- 0.3, 0.7 +/- 0.2, and 0.5 +/- 0.2 mm along the three axes, respectively. The experimental results with the simulated target shifts indicated that the positioning errors of the planned isocenter were 0.6 +/- 0.3, 0.7 +/- 0.2, and 0.5 +/- 0.2 mm along the three axes, respectively. On average, the positioning accuracy of 1 mm for the planned isocenter was achieved using the Novalis Body system.

  16. The global dimension of water governance: why the river basin approach is no longer sufficient and why cooperative action at global level is needed

    NARCIS (Netherlands)

    Hoekstra, Arjen Ysbert

    2011-01-01

    When water problems extend beyond the borders of local communities, the river basin is generally seen as the most appropriate unit for analysis, planning, and institutional arrangements. In this paper it is argued that addressing water problems at the river basin level is not always sufficient. Many

  17. Motorized fusion guided prostate biopsy: phantom study

    Science.gov (United States)

    Seifabadi, Reza; Xu, Sheng; Aalamifar, Fereshteh; Pinto, Peter; Wood, Bradford J.

    2017-03-01

    Purpose: Fusion of Magnetic Resonance Imaging (MRI) with intraoperative real-time Ultrasound (US) during prostate biopsy has significantly improved the sensitivity of transrectal ultrasound (TRUS) guided cancer detection. Currently, sweeping of the TRUS probe to build a 3D volume as part of the fusion process and the TRUS probe manipulation for needle guidance are both done manually. A motorized, joystick controlled, probe holder was custom fabricated that can potentially reduce inter-operator variability, provide standardization of needle placement, improve repeatability and uniformity of needle placement, which may have impacts upon the learning curve after clinical deployment of this emerging approach. Method: a 2DOF motorized probe holder was designed to provide translation and rotation of a triplane TRUS end firing probe for prostate biopsy. The probe holder was joystick controlled and can assist manipulation of the probe during needle insertion as well as in acquiring a smoother US 2D to 3D sweep in which the 3D US volume for fusion is built. A commercial MRI-US fusion platform was used. Three targets were specified on MR image of a commercial prostate phantom. After performing the registration, two operators performed targeting, once manually and once with the assistance of the motorized probe holder. They repeated these tasks 5 times resulting in a total of 30 targeting events. Time of completion and mechanical error i.e. distance of the target from the needle trajectory in the software user interface were measured. Repeatability in reaching a given target in a systematic and consistent way was measured using a scatter plot showing all targets in the US coordinate system. Pearson product-moment correlation coefficient (PPMCC) was used to demonstrate the probe steadiness during targeting. Results: the completion time was 25+/-17 sec, 25+/-24 sec, and 27+/-15 sec for free hand and 24+/-10 sec, 22.5+/-10 sec, and 37+/-10 sec for motorized insertion, for target

  18. Cooperative wireless communications

    CERN Document Server

    Zhang, Yan

    2009-01-01

    Cooperative devices and mechanisms are increasingly important to enhance the performance of wireless communications and networks, with their ability to decrease power consumption and packet loss rate and increase system capacity, computation, and network resilience. Considering the wide range of applications, strategies, and benefits associated with cooperative wireless communications, researchers and product developers need a succinct understanding of relevant theory, fundamentals, and techniques to navigate this challenging field. ""Cooperative Wireless Communications"" provides just that. I

  19. Primary motor cortex changes after amputation correlate with phantom limb pain and the ability to move the phantom limb

    DEFF Research Database (Denmark)

    Raffin, Estelle; Richard, Nathalie; Giraux, Pascal

    2016-01-01

    A substantial body of evidence documents massive reorganization of primary sensory and motor cortices following hand amputation, the extent of which is correlated with phantom limb pain. Many therapies for phantom limb pain are based upon the idea that plastic changes after amputation...... of reorganization, but the lip and elbow representations reorganized and shifted towards the hand area. We also found that poorer voluntary control and higher levels of pain in the phantom limb were powerful drivers of the lip and elbow topological changes. In addition to providing further support...... are maladaptive and attempt to normalize representations of cortical areas adjacent to the hand area. Recent data suggest, however, that higher levels of phantom pain are associated with stronger local activity and more structural integrity in the missing hand area rather than with reorganization of neighbouring...

  20. Cooperative Station History Forms

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Various forms, photographs and correspondence documenting the history of Cooperative station instrumentation, location changes, inspections, and...

  1. Futures for energy cooperatives

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-01-01

    A listing of Federal agencies and programs with potential funding for community-scale cooperatives using conservation measures and solar technologies is presented in Section 1. Section 2 presents profiles of existing community energy cooperatives describing their location, history, membership, services, sources of finance and technical assistance. A condensed summary from a recent conference on Energy Cooperatives featuring notes on co-op members' experiences, problems, and opportunities is presented in Section 3. Section 4 lists contacts for additional information. A National Consumer Cooperative Bank Load Application is shown in the appendix.

  2. Cooperation or Silent Rivalry?

    DEFF Research Database (Denmark)

    Zank, Wolfgang

    2010-01-01

    a gravitational pull which goes beyond economic problems. Furthermore, the EU has gradually built up a coherent policy on many fields. The EU has become the “reform anchor” and most important cooperation partner for Egypt. The progress towards increasing Egypt’s “Stake in the Internal Market” places cooperation...... on an increasingly institutionalized basis. In terms of military cooperation the US is still the partner for Egypt. But outside the military sphere institutionalized cooperation is comparatively week. In particular the failure of the US to conclude a free-trade agreement has been crucial. But it would be wrong...

  3. Evaluation of deformable image registration between external beam radiotherapy and HDR brachytherapy for cervical cancer with a 3D-printed deformable pelvis phantom.

    Science.gov (United States)

    Kadoya, Noriyuki; Miyasaka, Yuya; Nakajima, Yujiro; Kuroda, Yoshihiro; Ito, Kengo; Chiba, Mizuki; Sato, Kiyokazu; Dobashi, Suguru; Yamamoto, Takaya; Takahashi, Noriyoshi; Kubozono, Masaki; Takeda, Ken; Jingu, Keiichi

    2017-04-01

    In this study, we developed a 3D-printed deformable pelvis phantom for evaluating spatial DIR accuracy. We then evaluated the spatial DIR accuracies of various DIR settings for cervical cancer. A deformable female pelvis phantom was created based on patient CT data using 3D printing. To create the deformable uterus phantom, we first 3D printed both a model of uterus and a model of the internal cavities of the vagina and uterus. We then made a mold using the 3D printed uterus phantom. Finally, urethane was poured into the mold with the model of the internal cavities in place, creating the deformable uterus phantom with a cavity into which an applicator could be inserted. To create the deformable bladder phantom, we first 3D printed models of the bladder and of the same bladder scaled down by 2 mm. We then made a mold using the larger bladder model. Finally, silicone was poured into the mold with the smaller bladder model in place to create the deformable bladder phantom with a wall thickness of 2 mm. To emulate the anatomical bladder, water was poured into the created bladder. We acquired phantom image without applicator for EBRT. Then, we inserted the applicator into the phantom to simulate BT. In this situation, we scanned the phantom again to obtain the phantom image for BT. We performed DIR using the two phantom images in two cases: Case A, with full bladder (170 ml) in both EBRT and BT images; and Case B with full bladder in the BT image and half-full bladder (100 ml) in the EBRT image. DIR was evaluated using Dice similarity coefficients (DSCs) and 31 landmarks for the uterus and 25 landmarks for the bladder. A hybrid intensity and structure DIR algorithm implemented in RayStation with four DIR settings was evaluated. On visual inspection, reasonable agreement in shape of the uterus between the phantom and patient CT images was observed for both EBRT and BT, although some regional disagreements in shape of the bladder and rectum were apparent. The created

  4. Energy Efficient Resource Allocation for Phantom Cellular Networks

    KAUST Repository

    Abdelhady, Amr

    2016-04-01

    Multi-tier heterogeneous networks have become an essential constituent for next generation cellular networks. Meanwhile, energy efficiency (EE) has been considered a critical design criterion along with the traditional spectral efficiency (SE) metric. In this context, we study power and spectrum allocation for the recently proposed two-tier network architecture known as phantom cellular networks. The optimization framework includes both EE and SE. First, we consider sparsely deployed cells experiencing negligible interference and assume perfect channel state information (CSI). For this setting, we propose an algorithm that finds the SE and EE resource allocation strategies. Then, we compare the performance of both design strategies versus number of users, and phantom cells share of the total available resource units (RUs). We aim to investigate the effect of some system parameters to achieve improved SE performance at a non-significant loss in EE performance, or vice versa. It is found that increasing phantom cells share of RUs decreases the SE performance loss due to EE optimization when compared with the optimized SE performance. Second, we consider the densely deployed phantom cellular networks and model the EE optimization problem having into consideration the inevitable interference and imperfect channel estimation. To this end, we propose three resource allocation strategies aiming at optimizing the EE performance metric of this network. Furthermore, we investigate the effect of changing some of the system parameters on the performance of the proposed strategies, such as phantom cells share of RUs, number of deployed phantom cells within a macro cell coverage, number of pilots and the maximum power available for transmission by the phantom cells BSs. It is found that increasing the number of pilots deteriorates the EE performance of the whole setup, while increasing maximum power available for phantom cells transmissions reduces the EE of the whole setup in a

  5. [Mirror, mirror of the wall: mirror therapy in the treatment of phantom limbs and phantom limb pain].

    Science.gov (United States)

    Casale, Roberto; Furnari, Anna; Lamberti, Raul Coelho; Kouloulas, Efthimios; Hagenberg, Annegret; Mallik, Maryam

    2015-01-01

    Phantom limb and phantom limb pain control are pivotal points in the sequence of intervention to bring the amputee to functional autonomy. The alterations of perception and sensation, the pain of the residual limb and the phantom limb are therefore aspects of amputation that should be taken into account in the "prise en charge" of these patients. Within the more advanced physical therapies to control phantom and phantom limb pain there is the use of mirrors (mirror therapy). This article willfocus on its use and on the possible side effects induced by the lack of patient selection and a conflict of body schema restoration through mirror therapy with concurrent prosthetic training and trauma acceptance. Advice on the need to select patients before treatment decisions, with regard to their psychological as well as clinical profile (including time since amputation and clinical setting), and the need to be aware of the possible adverse effects matching different and somehow conflicting therapeutic approaches, are put forward. Thus a coordinated sequence of diagnostic, prognostic and therapeutic procedures carried out by an interdisciplinary rehabilitation team that works globally on all patients' problems is fundamental in the management of amputees and phantom limb pain. Further studies and the development of a multidisciplinary network to study this and other applications of mirror therapy are needed.

  6. 33 CFR 165.708 - Safety/Security Zone; Charleston Harbor and Cooper River, Charleston, SC.

    Science.gov (United States)

    2010-07-01

    ... Harbor and Cooper River, Charleston, SC. 165.708 Section 165.708 Navigation and Navigable Waters COAST... Guard District § 165.708 Safety/Security Zone; Charleston Harbor and Cooper River, Charleston, SC. (a... Cooper River. All coordinates referenced use datum: NAD 1983. (2) All waters within 100 yards of...

  7. 33 CFR 165.709 - Security Zone; Charleston Harbor, Cooper River, South Carolina.

    Science.gov (United States)

    2010-07-01

    ..., Cooper River, South Carolina. 165.709 Section 165.709 Navigation and Navigable Waters COAST GUARD... § 165.709 Security Zone; Charleston Harbor, Cooper River, South Carolina. (a) Regulated area. The Coast Guard is establishing a fixed security zone on all waters of the Cooper River, bank-to-bank and...

  8. Cellular cooperation: insights from microbes.

    Science.gov (United States)

    Celiker, Hasan; Gore, Jeff

    2013-01-01

    Cooperation between cells is a widespread phenomenon in nature, found across diverse systems ranging from microbial populations to multicellular organisms. For cooperation to evolve and be maintained within a population of cells, costs due to competition have to be outweighed by the benefits gained through cooperative actions. Because cooperation generally confers a cost to the cooperating cells, defector cells that do not cooperate but reap the benefits of cooperation can thrive and eventually drive the cooperating phenotypes to extinction. Here we summarize recent advances made in understanding how cooperation and multicellularity can evolve in microbial populations in the face of such conflicts and discuss parallels with cell populations within multicellular organisms.

  9. The visual phantom illusion: A perceptual product of surface completion depending on brightness and contrast.

    Science.gov (United States)

    Kitaoka, Akiyoshi; Gyoba, Jiro; Sakurai, Kenzo

    2006-01-01

    The visual phantom illusion was first discovered by Rosenbach in 1902 and named 'moving phantoms' by Tynan and Sekuler in 1975 because of its strong dependence on motion. It was later revealed that phantoms can be generated by flickering the grating (flickering phantoms) or by low-luminance stationary gratings under dark adaptation (stationary phantoms). Although phantoms are much more visible at scotopic or mesopic adaptation levels (scotopic phantoms) than at photopic levels, we proposed a new phantom illusion which is fully visible in photopic vision (photopic phantoms). In 2001, we revealed that the visual phantom illusion is a higher-order perceptual construct or a Gestalt, which depends on the mechanism of perceptual transparency. Perceptual transparency is known as a perceptual product based upon brightness and contrast. We furthermore manifested the shared mechanisms between visual phantoms and neon color spreading or between visual phantoms and the Petter effect. In our recent study, the visual phantom illusion can also be seen with a stimulus of contrast-modulated gratings. We assume that this effect also depends on perceptual transparency induced by contrast modulation. Moreover, we found that the Craik-O'Brien-Cornsweet effect and other brightness illusions can generate the visual phantom illusion. In any case, we explain the visual phantom illusion in terms of surface completion, which is given by perceptual transparency.

  10. WE-D-303-00: Computational Phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, John [Duke University Medical Center, Durham, NC (United States); Brigham and Women’s Hospital and Dana-Farber Cancer Institute, Boston, MA (United States)

    2015-06-15

    Modern medical physics deals with complex problems such as 4D radiation therapy and imaging quality optimization. Such problems involve a large number of radiological parameters, and anatomical and physiological breathing patterns. A major challenge is how to develop, test, evaluate and compare various new imaging and treatment techniques, which often involves testing over a large range of radiological parameters as well as varying patient anatomies and motions. It would be extremely challenging, if not impossible, both ethically and practically, to test every combination of parameters and every task on every type of patient under clinical conditions. Computer-based simulation using computational phantoms offers a practical technique with which to evaluate, optimize, and compare imaging technologies and methods. Within simulation, the computerized phantom provides a virtual model of the patient’s anatomy and physiology. Imaging data can be generated from it as if it was a live patient using accurate models of the physics of the imaging and treatment process. With sophisticated simulation algorithms, it is possible to perform virtual experiments entirely on the computer. By serving as virtual patients, computational phantoms hold great promise in solving some of the most complex problems in modern medical physics. In this proposed symposium, we will present the history and recent developments of computational phantom models, share experiences in their application to advanced imaging and radiation applications, and discuss their promises and limitations. Learning Objectives: Understand the need and requirements of computational phantoms in medical physics research Discuss the developments and applications of computational phantoms Know the promises and limitations of computational phantoms in solving complex problems.

  11. CREATION OF FEMALE COMPUTATIONAL PHANTOMS FOR CALIBRATION OF LUNG COUNTERS.

    Science.gov (United States)

    Lombardo, Pasquale Alessandro; Lebacq, Anne Laure; Vanhavere, Filip

    2016-09-01

    Plutonium isotopes are of high concern because they lead to high doses. In case of contamination, the activity burden inside the lungs should be assessed accurately. Many studies showed that the presence of breasts has a substantial influence on lung counting efficiencies. Currently, the calibration of most lung counting systems is done by means of physical phantoms representing only male chests. A set of female computational phantoms has been developed in order to provide gender-specific efficiency calibrations for the (241)Am gamma emission (59.54 keV). The phantoms were created starting from a library of female chest phantoms provided by Institut de radioprotection et de sûreté nucléaire (IRSN) (Farah, J. Amélioration des mesures anthroporadiamétriques personnalisées assistées par calcul Monte Carlo: optimisation des temps de calculs et méthodologie de mesure pour l'établissement de la répartition d'activite. PhD Thesis, 2011). While the IRSN phantoms represent a supine measurement position, the SCK•CEN lung counter set-up requires the persons to be sitting in a chair. Using open-source software, the breast shapes of the original phantoms have been recreated to simulate the drooping of breasts in vertical sitting position. A Monte Carlo approach was chosen for calculating calibration coefficients for female lung counting. The results obtained with MCNPx 2.7 simulations showed a significant decrease in the detection efficiency. For bigger bust and breast sizes, the detection efficiency showed to be up to 10 times lower than the ones measured with the Livermore male torso phantom.

  12. Fuzzy classification of phantom parent groups in an animal model

    Directory of Open Access Journals (Sweden)

    Fikse Freddy

    2009-09-01

    Full Text Available Abstract Background Genetic evaluation models often include genetic groups to account for unequal genetic level of animals with unknown parentage. The definition of phantom parent groups usually includes a time component (e.g. years. Combining several time periods to ensure sufficiently large groups may create problems since all phantom parents in a group are considered contemporaries. Methods To avoid the downside of such distinct classification, a fuzzy logic approach is suggested. A phantom parent can be assigned to several genetic groups, with proportions between zero and one that sum to one. Rules were presented for assigning coefficients to the inverse of the relationship matrix for fuzzy-classified genetic groups. This approach was illustrated with simulated data from ten generations of mass selection. Observations and pedigree records were randomly deleted. Phantom parent groups were defined on the basis of gender and generation number. In one scenario, uncertainty about generation of birth was simulated for some animals with unknown parents. In the distinct classification, one of the two possible generations of birth was randomly chosen to assign phantom parents to genetic groups for animals with simulated uncertainty, whereas the phantom parents were assigned to both possible genetic groups in the fuzzy classification. Results The empirical prediction error variance (PEV was somewhat lower for fuzzy-classified genetic groups. The ranking of animals with unknown parents was more correct and less variable across replicates in comparison with distinct genetic groups. In another scenario, each phantom parent was assigned to three groups, one pertaining to its gender, and two pertaining to the first and last generation, with proportion depending on the (true generation of birth. Due to the lower number of groups, the empirical PEV of breeding values was smaller when genetic groups were fuzzy-classified. Conclusion Fuzzy

  13. Cooperation or Silent Rivalry?

    DEFF Research Database (Denmark)

    Zank, Wolfgang

    2010-01-01

    on an increasingly institutionalized basis. In terms of military cooperation the US is still the partner for Egypt. But outside the military sphere institutionalized cooperation is comparatively week. In particular the failure of the US to conclude a free-trade agreement has been crucial. But it would be wrong...

  14. Readings in Cooperative Education.

    Science.gov (United States)

    Leventhal, Jerome I.

    Twenty-three journal articles on cooperative education were selected in a review of the literature by two Temple University graduate classes in the fall of 1975 and the spring of 1976 for those interested in the role of coordinating cooperative education programs. The journal readings consist of articles on theory/planning (6), implementation…

  15. Coordination and Cooperation

    OpenAIRE

    Janssen, Maarten

    2003-01-01

    textabstractThis comment makes four related points. First, explaining coordination is different from explaining cooperation. Second, solving the coordination problem is more important for the theory of games than solving the cooperation problem. Third, a version of the Principle of Coordination can be rationalized on individualistic grounds. Finally, psychological game theory should consider how players perceive their gaming situation. ---------------------------------------------------------...

  16. Cooperation, compensation and transition

    NARCIS (Netherlands)

    Ju, Y.

    2004-01-01

    Cooperation and compensation are two important and well-linked issues in economics. The central question in cooperation is how to share the joint gains among participating players. Compensation is a specific aspect of surplus sharing problems providing incentives for agents to sacrifice their own di

  17. Cooperative Science Lesson Plans.

    Science.gov (United States)

    Cooperative Learning, 1991

    1991-01-01

    Offers several elementary level cooperative science lesson plans. The article includes a recipe for cooperative class learning, instructions for making a compost pile, directions for finding evidence of energy, experiments in math and science using oranges to test density, and discussions of buoyancy using eggs. (SM)

  18. Cooperative Learning Strategies.

    Science.gov (United States)

    Barnes, Buckley; O'Farrell, Gail

    1990-01-01

    Presents essential characteristics and types of cooperative learning strategies for use in elementary social studies. Outlines exercises for forming teams and building team spirit. Points out such methods promote group interdependence and student responsibility for learning and teaching others. Highlights two cooperative group strategies, Jigsaw…

  19. Coordination and Cooperation

    NARCIS (Netherlands)

    M.C.W. Janssen (Maarten)

    2003-01-01

    textabstractThis comment makes four related points. First, explaining coordination is different from explaining cooperation. Second, solving the coordination problem is more important for the theory of games than solving the cooperation problem. Third, a version of the Principle of Coordination can

  20. International Cooperation Advances Internationalization

    Institute of Scientific and Technical Information of China (English)

    Ge Mingyi

    2004-01-01

    @@ Intemational scientific cooperation continues to successfully promote the development of research and the quality of researchers in China, and also the internationalization of China's research system and research organizations. An outstanding example of this is the 30 years of fruitful cooperation between the Chinese Academy of Sciences and the Max Planck Society.

  1. Coordination and Cooperation

    NARCIS (Netherlands)

    M.C.W. Janssen (Maarten)

    2003-01-01

    textabstractThis comment makes four related points. First, explaining coordination is different from explaining cooperation. Second, solving the coordination problem is more important for the theory of games than solving the cooperation problem. Third, a version of the Principle of Coordination can

  2. Efficiency in Microfinance Cooperatives

    Directory of Open Access Journals (Sweden)

    HARTARSKA, Valentina

    2012-12-01

    Full Text Available In recognition of cooperatives’ contribution to the socio-economic well-being of their participants, the United Nations has declared 2012 as the International Year of Cooperatives. Microfinance cooperatives make a large part of the microfinance industry. We study efficiency of microfinance cooperatives and provide estimates of the optimal size of such organizations. We employ the classical efficiency analysis consisting of estimating a system of equations and identify the optimal size of microfinance cooperatives in terms of their number of clients (outreach efficiency, as well as dollar value of lending and deposits (sustainability. We find that microfinance cooperatives have increasing returns to scale which means that the vast majority can lower cost if they become larger. We calculate that the optimal size is around $100 million in lending and half of that in deposits. We find less robust estimates in terms of reaching many clients with a range from 40,000 to 180,000 borrowers.

  3. Culture and cooperation.

    Science.gov (United States)

    Gächter, Simon; Herrmann, Benedikt; Thöni, Christian

    2010-09-12

    Does the cultural background influence the success with which genetically unrelated individuals cooperate in social dilemma situations? In this paper, we provide an answer by analysing the data of Herrmann et al. (2008a), who studied cooperation and punishment in 16 subject pools from six different world cultures (as classified by Inglehart & Baker (2000)). We use analysis of variance to disentangle the importance of cultural background relative to individual heterogeneity and group-level differences in cooperation. We find that culture has a substantial influence on the extent of cooperation, in addition to individual heterogeneity and group-level differences identified by previous research. The significance of this result is that cultural background has a substantial influence on cooperation in otherwise identical environments. This is particularly true in the presence of punishment opportunities.

  4. Molecular dynamics simulation of the cooperative adsorption of barley lipid transfer protein and cis-isocohumulone at the vacuum-water interface.

    Science.gov (United States)

    Euston, S R; Hughes, P; Naser, Md A; Westacott, R E

    2008-11-01

    Molecular dynamic simulations have been carried out on systems containing a mixture of barley lipid transfer protein (LTP) and cis-isocohumulone (a hop derived iso-alpha-acid) in one of its enol forms, in bulk water and at the vacuum-water interface. In solution, the cis-isocohumulone molecules bind to the surface of the LTP molecule. The mechanism of binding appears to be purely hydrophobic in nature via desolvation of the protein surface. Binding of hop acids to the LTP leads to a small change in the 3-D conformation of the protein, but no change in the proportion of secondary structure present in helices, even though there is a significant degree of hop acid binding to the helical regions. At the vacuum-water interface, cis-isocohumulone shows a high surface activity and adsorbs rapidly at the interface. LTP then shows a preference to bind to the preadsorbed hop acid layer at the interface rather than to the bare water-vacuum interface. The free energy of adsorption of LTP at the hop-vacuum-water interface is more favorable than for adsorption at the vacuum-water interface. Our results support the view that hop iso-alpha-acids promote beer foam stability by forming bridges between separate adsorbed protein molecules, thus strengthening the adsorbed protein layer and reducing foam breakdown by lamellar phase drainage. The results also suggest a second mechanism may also occur, whereby the concentration of protein at the interface is increased via enhanced protein adsorption to adsorbed hop acid layers. This too would increase foam stability through its effect on the stabilizing protein layer around the foam bubbles.

  5. Using CBCT for pretreatment range check in proton therapy: a phantom study for prostate treatment by anterior-posterior beam.

    Science.gov (United States)

    Bentefour, El Hassane; Both, Stefan; Tang, Shikui; Lu, Hsiao-Ming

    2015-11-08

    This study explores the potential of cone-beam computed tomography (CBCT) for monitoring relative beam range variations due to daily changes in patient anatomy for prostate treatment by anterior proton beams. CBCT was used to image an anthropomorphic pelvic phantom, in eight sessions on eight different days. In each session, the phantom was scanned twice, first at a standard position as determined by the room lasers, and then after it was shifted by 10 mm translation randomly along one of the X, Y, or Z directions. The filling of the phantom bladder with water was not refreshed from day to day, inducing gradual change of the water-equivalent path length (WEPL) across the bladder. MIMvista (MIM) software was used to perform image registration and re-alignment of all the scans with the scan from the first session. The XiO treatment planning system was used to perform data analysis. It was found that, although the Hounsfield unit numbers in CBCT have substantially larger fluctuations than those in diagnostic CT, CBCT datasets taken for daily patient positioning could potentially be used to monitor changes in patient anatomy. The reproducibility of the WEPL, computed using CBCT along anterior-posterior (AP) paths across and around the phantom prostate, over a volume of 360 cc, is sufficient for detecting daily WEPL variations that are equal to or larger than 3 mm. This result also applies to CBCT scans of the phantom after it is randomly shifted from the treatment position by 10 mm. limiting the interest to WEPL variation over a specific path within the same CBCT slice, one can detect WEPL variation smaller than 1 mm. That is the case when using CBCT for tracking daily change of the WEPL across the phantom bladder that was induced by spontaneous change in the bladder filling due to evaporation. In summary, the phantom study suggests that CBCT can be used for monitoring day to day WEPL variations in a patient. The method can detect WEPL variation equal to or greater

  6. Development and implementation of an anthropomorphic pediatric spine phantom for the assessment of craniospinal irradiation procedures in proton therapy

    Directory of Open Access Journals (Sweden)

    Dana J Lewis

    2014-03-01

    Full Text Available Purpose: To design an anthropomorphic pediatric spine phantom for use in the evaluation of proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core (IROC Houston QA Center (formerly RPC.Methods: This phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation by the treatment planning system (TPS, and proton treatment delivery. The design incorporated materials simulating the thoracic spinal column of a pediatric patient, along with two thermoluminescent dosimeter (TLD-100 capsules and radiochromic film embedded in the phantom for dose evaluation. Fourteen potential materials were tested to determine relative proton stopping power (RSP and Hounsfield unit (HU values. Each material was CT scanned at 120 kVp, and the RSP was obtained from depth ionization scans using the Zebra multi-layer ion chamber (MLIC at two energies: 160 MeV and 250 MeV. To determine tissue equivalency, the measured RSP for each material was compared to the RSP calculated by the Eclipse TPS for a given HU.Results: The materials selected as bone, tissue, and cartilage substitutes were Techron HPV Bearing Grade (Boedeker Plastics, Inc., solid water, and blue water, respectively. The RSP values did not differ by more than 1.8% between the two energies. The measured RSP for each selected material agreed with the RSP calculated by the Eclipse TPS within 1.2%.Conclusion: An anthropomorphic pediatric proton spine phantom was designed to evaluate proton therapy delivery. The inclusion of multiple tissue substitutes increases heterogeneity and the level of difficulty for institutions to successfully treat the phantom. The following attributes will be evaluated: absolute dose agreement, distal range, field width, junction match and right/left dose profile alignment. The phantom will be tested at several institutions using a 5% dose agreement criterion, and a 5%/3mm gamma

  7. Pulling telescoped phantoms out of the stump: Manipulating the perceived position of phantom limbs using a full-body illusion

    Directory of Open Access Journals (Sweden)

    Laura eSchmalzl

    2011-11-01

    Full Text Available Most amputees experience phantom limbs, or the sensation that their amputated limb is still attached to the body. Phantom limbs can be perceived in the location previously occupied by the intact limb, or they can gradually retract inside the stump, a phenomenon referred to as telescoping. Telescoping is relevant from a clinical point of view, as it tends to be related to increased levels of phantom pain. In the current study we demonstrate how a full-body illusion can be used to temporarily revoke telescoping sensations in upper limb amputees. During this illusion participants view the body of a mannequin from a first person perspective while being subjected to synchronized visuo-tactile stimulation through stroking, which makes them experience the mannequin’s body as their own. In Experiment 1 we used an intact mannequin, and showed that amputees can experience ownership of an intact body as well as referral of touch from both hands of the mannequin. In Experiment 2 and 3 we used an amputated mannequin, and demonstrated that depending on the spatial location of the strokes applied to the mannequin, participants experienced their phantom hand to either remain telescoped, or to actually be located below the stump. The effects were supported by subjective data from questionnaires, as well as verbal reports of the perceived location of the phantom hand in a visual judgment task. These findings are of particular interest, as they show that the temporary revoking of telescoping sensations does not necessarily have to involve the visualization of an intact hand or illusory movement of the phantom (as in the rubber hand illusion or mirror visual feedback therapy, but that it can also be obtained through mere referral of touch from the stump to the spatial location corresponding to that previously occupied by the intact hand. Moreover, our study also provides preliminary evidence for the fact that these manipulations can have an effect on phantom pain

  8. An anthropomorphic multimodality (CT/MRI) phantom prototype for end-to-end tests in radiation therapy

    CERN Document Server

    Gallas, Raya R; Runz, Armin; Niebuhr, Nina I; Jäkel, Oliver; Greilich, Steffen

    2014-01-01

    With the increasing complexity of external beam therapy, so-called "end-to-end" tests are intended to cover all steps from therapy planning to follow-up to fulfill the high demands on quality assurance. As magnetic resonance imaging (MRI) gains growing importance in the treatment process and established phantoms (such as the Alderson head) cannot be used for those tests, novel multimodality phantoms have to be developed. Here, we present a feasibility study for such a customizable multimodality head phantom. We used a set of patient CT images as the basis for the anthropomorphic head shape. The recipient - consisting of an epoxy resin - was produced using rapid prototyping (3D printing). The phantom recipient includes a nasal air cavity, two soft tissues volumes and cranial bone. Additionally a spherical tumor volume was positioned in the center. The volumes were filled with dipotassium phosphate-based cranial bone surrogate, agarose gel, and distilled water. The tumor volume was filled with normoxic dosimetr...

  9. A 'quad-phantom' film dosimeter for use as a multi-planar verification tool for PRESAGE/optical-CT.

    Science.gov (United States)

    Stunja, L; Thomas, A; Adamovics, J; Deasy, J; Oldham, M

    2010-01-01

    INTRODUCTION: To develop and characterize the accuracy and reproducibility of a quad-phantom dosimeter which will serve as an independent verification tool during commissioning of a PRESAGE/optical-CT 3D dosimetry system. METHODS: A 16cm × 12cm cylindrical quad-phantom was constructed from four pieces of solid polyurethane mimicking the PRESAGE material. Films were placed and anchored in orthogonal planes and the quad-phantom was fastened tightly together and placed in a water-filled Styrofoam container for irradiation. A simple, two-field plan consisting of 6×6cm anterior-posterior and right-lateral 6MV photon beams (400cGy) was delivered three times (fresh films inserted for each) with a Varian Clinac 600C. Image registration was performed in the Computational Environment for Radiological Research (CERR) and dose profiles and gamma analysis was performed in CERR and MATLAB. RESULTS #ENTITYSTARTX00026; DISCUSSION: Excellent reproducibility was observed during the irradiations, with ~2.3% standard deviation between all pixels. Using a 3%, 3mm gamma criteria, excellent dosimetric accuracy was observed, with 98.8% and 96.3% passing rates in the sagittal and axial planes, respectively. CONCLUSION: The preliminary results indicate that the quad-phantom can serve as a reproducible and accurate system for high resolution dosimetry in orthogonal planes and should serve as an effective verification tool for PRESAGE/optical-CT in more challenging clinical scenarios.

  10. Validation of a cylindrical phantom for verification of radiotherapy treatments in head and neck with special techniques

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, Nicolas M.; Garcia, Marcia, E-mail: nimoralesv@gmail.com [Universidad de La Frontera, Temuco (Chile). Dept. de Ciencias Fisicas; Piriz, Gustavo [Instituto Nacional del Cancer, Santiago (Chile). Fisica Medica; Perez, Niurka [Instituto de Salud Publica, Santiago (Chile). QA Radioterapia. Inst. de Salud Publica

    2011-07-01

    Verification of radiotherapy treatments in head and neck requires, among other things, small volume chambers and a phantom to reproduce the geometry and density of the anatomical structure. New documents from the ICRU (International Commission on Radiation Units and Measurements), Report 83, established the need for quality control in radiotherapy with special techniques such as IMRT (intensity-modulated radiation therapy). In this study, we built a cylindrical acrylic phantom with standing water, containing seven measuring points in the transverse plane and free location (0-20 cm) in the longitudinal plane. These points of measurement are constituted by cavities for the accommodation of the ionization chamber of 7 mm of mayor diameter (semi flex, pinpoint with build cup). The results of the phantom validation yielded percentage differences less than 1% in fixed beams and less than 2.5% in arc therapy for TPS Eclipse calculation. The preparation of this phantom, particularly made to verify the head and neck treatments, was simple and reliable for checking the dose in radiotherapy with fixed beams and/or special techniques such as arc therapy or IMRT, so that will be sent to various radiotherapy centers in the country for dosimetric verification in such treatments. (author)

  11. A 'quad-phantom' film dosimeter for use as a multi-planar verification tool for PRESAGE/optical-CT

    Science.gov (United States)

    Stunja, L.; Thomas, A.; Adamovics, J.; Deasy, J.; Oldham, M.

    2010-11-01

    Introduction: To develop and characterize the accuracy and reproducibility of a 'quad-phantom' dosimeter which will serve as an independent verification tool during commissioning of a PRESAGE/optical-CT 3D dosimetry system. Methods: A 16cm × 12cm cylindrical quad-phantom was constructed from four pieces of solid polyurethane mimicking the PRESAGE material. Films were placed and anchored in orthogonal planes and the quad-phantom was fastened tightly together and placed in a water-filled Styrofoam container for irradiation. A simple, two-field plan consisting of 6×6cm anterior-posterior and right-lateral 6MV photon beams (400cGy) was delivered three times (fresh films inserted for each) with a Varian Clinac 600C. Image registration was performed in the Computational Environment for Radiological Research (CERR) and dose profiles and gamma analysis was performed in CERR and MATLAB. Results & Discussion: Excellent reproducibility was observed during the irradiations, with ~2.3% standard deviation between all pixels. Using a 3%, 3mm gamma criteria, excellent dosimetric accuracy was observed, with 98.8% and 96.3% passing rates in the sagittal and axial planes, respectively. Conclusion: The preliminary results indicate that the quad-phantom can serve as a reproducible and accurate system for high resolution dosimetry in orthogonal planes and should serve as an effective verification tool for PRESAGE/optical-CT in more challenging clinical scenarios.

  12. OSL Based Anthropomorphic Phantom and Real-Time Organ Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    David E. Hintenlang, Ph.D

    2009-02-10

    The overall objective of this project was the development of a dosimetry system that provides the direct measurement of organ does in real-time with a sensitivity that makes it an effective tool for applications in a wide variety of health physics applications. The system included the development of a real-time readout system for fiber optic coupled (FOC) dosimeters that is integrated with a state-of-art anthropomorphic phantom to provide instantaneous measures of organ doses throughout the phantom. The small size of the FOC detectors and optical fibers allow the sensitive volume of the detector to be located at organ centroids (or multiple locations distributed through the organ) within a tissue equivalent, anthropomorphic phantom without perturbing the tissue equivalent features of the phantom. The developed phantom/dosimetry system can be used in any environment where personnel may be exposed to gamma or x-ray radiations to provide the most accurate determinations of organ and effective doses possible to date.

  13. Radiological equipment analyzed by specific developed phantoms and software

    Energy Technology Data Exchange (ETDEWEB)

    Soto, M.; Campayo, J. M. [Logistica y Acondicionamientos Industriales SAU, Sorolla Center, Local 10, Av. de las Cortes Valencianas No. 58, 46015 Valencia (Spain); Mayo, P. [TITANIA Servicios Tecnologicos SL, Sorolla Center, Local 10, Av. de las Cortes Valencianas No. 58, 46015 Valencia (Spain); Verdu, G.; Rodenas, F., E-mail: m.soto@lainsa.co [ISIRYIM Universidad Politecnica de Valencia, Camino de Vera s/n, Valencia (Spain)

    2010-10-15

    The use of radiographic phantoms specifically designed to evaluate the operation of the radiographic equipment lets the study of the image quality obtained by this equipment in an objective way. In digital radiographic equipment, the analysis of the image quality can be computerized because the acquisition of the image is possible in different technologies that are, computerized radiography or phosphor plate and direct radiography or detector. In case of film-screen equipment s this analysis could be applied digitalising the image in a professional scanner. In this work we have shown an application to assess automatically the constancy quality image in the image chain of the radiographic equipment s. This application is integrated by designed radiographic phantoms which are adapted to conventional, dental equipment s and specific developed software for the automatic evaluation of the phantom image quality. The software is based on digital image processing techniques that let the automatic detection of the different phantom tests by edge detector, morphological operators, threshold histogram techniques... etc. The utility developed is enough sensitive to the radiographic equipment of operating conditions of voltage (kV) and charge (m As). It is a friendly user programme connected with a data base of the hospital or clinic where it has been used. After the phantom image processing the user can obtain an inform with a resume of the imaging system state with accepting and constancy results. (Author)

  14. Evaluation of SPECT imaging using myocardial phantoms in Akita prefecture

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Kiyohiko [Akita Univ. (Japan). Hospital; Watarai, Jiro; Miura, Mamoru

    1998-09-01

    Evaluation of SPECT imaging using myocardial phantom in Akita Prefecture. The Society of Nuclear Medicine for Circulation disease in Akita was established in July, 1997. To improve myocardial spect imaging in Akita Prefecture, we first visually evaluated two acrlic defect (2 cm{phi} x 1 cm thickness aqcliel and 1 cm{phi} x 1 cm thickness) images of long axis and short axis of myocardial phantoms, using 14 SPECT Cameras. These defect images of myocardial phantom were evaluated by four cardiologists and twelve radiologists between August and December, 1996. Secondly, we measured the FWHM of four line sources (anterior, lateral, inferior, and septum positions in the short axis of myocardial phantom) using quantitative analysis by myocardial phantom between April and July, 1997. The results were reported at the 4th and 5th meeting of the Society of Nuclear Medicine for Circulation Disease in Akita. In conclusion, about 70% of myocardial spect images were of good or normal quality, whereas about 30% of the images were evaluated as of bad quality. To improve the myocardial spect images, we recognized that the basic performance of the SPECT cameras need be investigated. (author)

  15. Construction tool and suitability of voxel phantom for skin dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, Paula C.G.; Siqueira, Paulo T.D.; Fonseca, Gabriel P.; Yoriyaz, Helio, E-mail: ptsiquei@ipen.b, E-mail: hyoriyaz@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    This paper describes a new software tool called 'SkinVop' which was developed to enable accurate voxel phantom skin dosimetry. A voxel phantom is a model used to describe human anatomy in a realistic way in radiation transport codes. This model is a three-dimensional representation of the human body in the form of an array of identification numbers that are arranged in a 3D matrix. Each entry in this array represents a voxel (volume element) directly associated to the units of picture resolution (pixel) of medical images. Currently, these voxel phantoms, in association with the transport code MCNP (Monte Carlo N-Particle), have provided subsidies to the planning systems used on the hospital routine, once they afford accurate and personalized estimative of dose distribution. However, these assessments are limited to geometric representations of organs and tissues in the voxel phantom, which do not discriminates some thin body structure, such as the skin. In this context, to enable accurate dosimetric skin dose assessment by the MCNP code, it was developed this new software tool that discriminates this region with thickness and localization in the voxel phantoms similar to the real. This methodology consists in manipulating the skin volume elements by segmenting and subdividing them in different thicknesses. A graphical user interface was designed to fulfill display the modified voxel model. This methodology is extremely useful once the skin dose is inaccurately assessed of current hospital system planning, justified justly by its small thickness. (author)

  16. A methodology for developing anisotropic AAA phantoms via additive manufacturing.

    Science.gov (United States)

    Ruiz de Galarreta, Sergio; Antón, Raúl; Cazón, Aitor; Finol, Ender A

    2017-05-24

    An Abdominal Aortic Aneurysm (AAA) is a permanent focal dilatation of the abdominal aorta at least 1.5 times its normal diameter. The criterion of maximum diameter is still used in clinical practice, although numerical studies have demonstrated the importance of biomechanical factors for rupture risk assessment. AAA phantoms could be used for experimental validation of the numerical studies and for pre-intervention testing of endovascular grafts. We have applied multi-material 3D printing technology to manufacture idealized AAA phantoms with anisotropic mechanical behavior. Different composites were fabricated and the phantom specimens were characterized by biaxial tensile tests while using a constitutive model to fit the experimental data. One composite was chosen to manufacture the phantom based on having the same mechanical properties as those reported in the literature for human AAA tissue; the strain energy and anisotropic index were compared to make this choice. The materials for the matrix and fibers of the selected composite are, respectively, the digital materials FLX9940 and FLX9960 developed by Stratasys. The fiber proportion for the composite is equal to 0.15. The differences between the composite behavior and the AAA tissue are small, with a small difference in the strain energy (0.4%) and a maximum difference of 12.4% in the peak Green strain ratio. This work represents a step forward in the application of 3D printing technology for the manufacturing of AAA phantoms with anisotropic mechanical behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. High resolution, MRI-based, segmented, computerized head phantom

    Energy Technology Data Exchange (ETDEWEB)

    Zubal, I.G.; Harrell, C.R.; Smith, E.O.; Smith, A.L.; Krischlunas, P. [Yale Univ., New Haven, CT (United States). Dept. of Diagnostic Radiology

    1999-01-01

    The authors have created a high-resolution software phantom of the human brain which is applicable to voxel-based radiation transport calculations yielding nuclear medicine simulated images and/or internal dose estimates. A software head phantom was created from 124 transverse MRI images of a healthy normal individual. The transverse T2 slices, recorded in a 256x256 matrix from a GE Signa 2 scanner, have isotropic voxel dimensions of 1.5 mm and were manually segmented by the clinical staff. Each voxel of the phantom contains one of 62 index numbers designating anatomical, neurological, and taxonomical structures. The result is stored as a 256x256x128 byte array. Internal volumes compare favorably to those described in the ICRP Reference Man. The computerized array represents a high resolution model of a typical human brain and serves as a voxel-based anthropomorphic head phantom suitable for computer-based modeling and simulation calculations. It offers an improved realism over previous mathematically described software brain phantoms, and creates a reference standard for comparing results of newly emerging voxel-based computations. Such voxel-based computations lead the way to developing diagnostic and dosimetry calculations which can utilize patient-specific diagnostic images. However, such individualized approaches lack fast, automatic segmentation schemes for routine use; therefore, the high resolution, typical head geometry gives the most realistic patient model currently available.

  18. Capturing the Perceived Phantom Limb through Virtual Reality

    Directory of Open Access Journals (Sweden)

    Christian Rogers

    2016-01-01

    Full Text Available Phantom limb is the sensation amputees may feel when the missing limb is still attached to the body and is still moving as it would if it still existed. Despite there being between 50 and 80% of amputees who report neuropathic pain, also known as phantom limb pain (PLP, there is still little understanding of why PLP occurs. There are no fully effective long-term treatments available. One of the struggles with PLP is the difficulty for amputees to describe the sensations of their phantom limbs. The sensations may be of a limb that is in a position that is impossible for a normal limb to attain. The goal of this project was to treat those with PLP by developing a system to communicate the sensations those with PLP were experiencing accurately and easily through various hand positions using a model arm with a user friendly interface. The system was developed with Maya 3D animation software, the Leap Motion input device, and the Unity game engine. The 3D modeled arm was designed to mimic the phantom sensation being able to go beyond normal joint extensions of regular arms. The purpose in doing so was to obtain a true 3D visualization of the phantom limb.

  19. The Cooperative Study on Energy and Water Cycle over the Tibetan Plateau%青藏高原能量与水循环国际合作研究的进展与展望

    Institute of Scientific and Technical Information of China (English)

    马耀明; 姚檀栋; 胡泽勇; 王介民

    2009-01-01

    The processes of energy and water cycle over the Tibetan Plateau have shown that the giant prominence exerts thermal effects on the atmosphere, thus greatly influencing atmospheric circulations over China, Asia and even the globle. Focusing on this issue, the intensive observation period (IOP) and long-term observation of the GEWEX (Global Energy and Water cycle Experiment) Asian Monsoon Experiment on the Tibetan Plateau ( GAME/Tibet ) and CEOP (Coordinated Enhanced Observing Period) Asia Australia Monsoon Project (CAMP) on the Tibetan Plateau (CAMP/ Tibet ) have been carried out successfully from the beginning of 1996 under the support of National Natural Science Foundation of China (NSFC) , the Chinese Academy of Sciences (CAS) , the China Meteorological Administration (CMA) and the Japanese government etc. A large number of data has been collected, which is the best data set so far for the study of energy and water cycle over the Tibetan Plateau. Great progress has been made in the study of energy and water cycle over the Tibetan Plateau through the in-situ data analysis, satellite remote sensing parameterization and the numerical modeling, etc. The progresses of the study of energy and water cycle over the Tibetan Plateau and the role of the international cooperation in the projects will be introduced in detail. The role of the international cooperation in getting the research found from abroad and in training young scientists and students is also mentioned. The existing problems in the international cooperation and the solving ways are presented in the paper at the same time.%青藏高原能量与水循环过程对我国、东亚乃至全球的天气和气候系统都有着非常重要的作用.1996年以来,在国家自然科学基金委员会、中国科学院、中国气象局等相关部门和日本政府的大力支持下,我们针对青藏高原能量和水循环过程的重要性,成功地开展了青藏高原尺度和藏北地区中尺度的"全球能

  20. Development and application of a pediatric head phantom for dosimetry in computed tomography; Desenvolvimento e aplicacao de um simulador pediatrico craniano para dosimetria em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Elaine Wirney

    2016-11-01

    To determine the exposure levels and the absorbed dose in patients undergoing CT scans, is necessary to calculate the CT dose index in measurements with a PMMA or water phantom. The phantom must be enough to simulate the attenuation and scattering characteristics of a human body or parts in a radiation field. The CT specific quantities : CT air kerma index (Ca,100) , weighted CT air kerma index (CW ), a total volume CT air kerma index (Cvol) and the CT air kerma-length product (PKL) must be determined and compared to literature reference levels. In this work a head pediatric phantom was developed, considering that the Brazilian published Diagnostic Reference Levels (DRL) are based on adult phantom measurements. This developed phantom shows a construction innovation using materials to simulate the skullcap, cortical bone (aluminum) and cancellous bone (PVC), and it was filled with distilled water. The phantom dimension follows the recommendations of the World Health Organization and the International Commission on Radiation Units for children from 0 to 5 years old head size: diameter of 160 mm and height of 155 mm. The skullcap has 4 mm of thickness and 111.9 mm of internal diameter. In order to evaluate its behavior, tests were carried out in calibration laboratories and in clinical beams. The results showed attenuation up to 23% when different materials are used as skullcap, demonstrating that the DRLs adopted could be overestimating the dose received by pediatric patients. It is observed that the dose received by CT skull scans presents different distribution, due to the skullcap partially attenuation and/or backscattering which is not considered when the PMMA phantom is used.

  1. Development of cooperative system bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhe; WAN Qi-bai; SHI Lei

    2008-01-01

    Cooperative system bridges comprise several basic structures that act jointly to improve structural characteristics. We delved into the historical development of cooperative system bridges. Cooperative systems are classified as different-load cooperative systems and same-load cooperative systems by distinguishing the modes of load distribution. For different-load cooperation, individual basic structures are at different positions in the direction along bridge axis and carry the loads separately. While for same-load cooperation, all basic structures overlap in geometrical locations and support the entire loads conjointly. The choosing of span ratios between basic structures, the design of connections of different-load cooperative systems were discussed as well as optimizations of relative rigidity for same-load cooperative systems which greatly influence structural characteristics. The general situation and several structural measurements of several cooperative bridges were demonstrated. This information can assist engineers in developing their concepts in cooperative systems and can lead to more efficient and economical cooperative bridges.

  2. Network modularity promotes cooperation.

    Science.gov (United States)

    Marcoux, Marianne; Lusseau, David

    2013-05-01

    Cooperation in animals and humans is widely observed even if evolutionary biology theories predict the evolution of selfish individuals. Previous game theory models have shown that cooperation can evolve when the game takes place in a structured population such as a social network because it limits interactions between individuals. Modularity, the natural division of a network into groups, is a key characteristic of all social networks but the influence of this crucial social feature on the evolution of cooperation has never been investigated. Here, we provide novel pieces of evidence that network modularity promotes the evolution of cooperation in 2-person prisoner's dilemma games. By simulating games on social networks of different structures, we show that modularity shapes interactions between individuals favouring the evolution of cooperation. Modularity provides a simple mechanism for the evolution of cooperation without having to invoke complicated mechanisms such as reputation or punishment, or requiring genetic similarity among individuals. Thus, cooperation can evolve over wider social contexts than previously reported.

  3. Globalization and human cooperation.

    Science.gov (United States)

    Buchan, Nancy R; Grimalda, Gianluca; Wilson, Rick; Brewer, Marilynn; Fatas, Enrique; Foddy, Margaret

    2009-03-17

    Globalization magnifies the problems that affect all people and that require large-scale human cooperation, for example, the overharvesting of natural resources and human-induced global warming. However, what does globalization imply for the cooperation needed to address such global social dilemmas? Two competing hypotheses are offered. One hypothesis is that globalization prompts reactionary movements that reinforce parochial distinctions among people. Large-scale cooperation then focuses on favoring one's own ethnic, racial, or language group. The alternative hypothesis suggests that globalization strengthens cosmopolitan attitudes by weakening the relevance of ethnicity, locality, or nationhood as sources of identification. In essence, globalization, the increasing interconnectedness of people worldwide, broadens the group boundaries within which individuals perceive they belong. We test these hypotheses by measuring globalization at both the country and individual levels and analyzing the relationship between globalization and individual cooperation with distal others in multilevel sequential cooperation experiments in which players can contribute to individual, local, and/or global accounts. Our samples were drawn from the general populations of the United States, Italy, Russia, Argentina, South Africa, and Iran. We find that as country and individual levels of globalization increase, so too does individual cooperation at the global level vis-à-vis the local level. In essence, "globalized" individuals draw broader group boundaries than others, eschewing parochial motivations in favor of cosmopolitan ones. Globalization may thus be fundamental in shaping contemporary large-scale cooperation and may be a positive force toward the provision of global public goods.

  4. [The treatment of the phantom pain syndrome with tizanidine].

    Science.gov (United States)

    Vorobeĭchik, Ia M; Kukushkin, M L; Reshetniak, V K; Ovechkin, A M; Gnezdilov, A V

    1997-01-01

    The authors carried out estimation of analgetic effect of tisanidin by double blind test in patients with phantom limb pain syndrome. 14 patients took the medicine in a dose of 12 mg/day and 5 patients took placebo at the same dose. Characteristics and intensity of pain were estimated in accordance with McGill pain questionnaire and visual analogue scale. Pain possessed more than one sensory characteristics in the majority of patients. Tisanidin had a significant analgetic influence on all type of phantom limb pain: "neuralgic"--acute, shooting, transitory, "causalgic"--hot, burning, searing, "cramping" pain. Pain sensation did not decrease only in one of 14 patients treated with tisanidin. The authors explain the effectivity of the drug for treatment of phantom limb pain of different sensory modality by variety of the mechanisms of its therapeutic action, the capacity to decrease the releasing of excitatory neurotransmitter amino acids and the influence on alpha 2-adrenoceptors.

  5. Full scattering profile of circular optical phantoms mimicking biological tissue

    Science.gov (United States)

    Feder, Idit; Wróbel, Maciej S.; Duadi, Hamootal; Fixler, Dror; Jedrzejewska-Szczerska, Malgorzata

    2017-02-01

    Human tissue is one of the most complex optical media since it is turbid and nonhomogeneous. In our poster, we suggest a new type of skin phantom and an optical method for sensing physiological tissue condition, basing on the collection of the ejected light at all exit angles, to receive the full scattering profile. Conducted experiments were carried out on an unique set-up for noninvasive encircled measurement. Set-up consisted of a laser, a photodetector and new tissues-like phantoms made with a polyvinyl chloride-plastisol (PVCP), silicone elastomer polydimethylsiloxane (PDMS) and PDMS with glycerol mixture. Our method reveals an isobaric point, which is independent of the optical properties. Furthermore, we present the angular distribution of cylindrical phantoms, in order to sense physiological tissue state.

  6. Ballistic gelatin as a putative substrate for EEG phantom devices

    CERN Document Server

    Hairston, W David; Yu, Alfred B

    2016-01-01

    Phantom devices allow the human variable to be controlled for in order to allow clear comparison and validation of biomedical imaging hardware and software. There is currently no standard phantom for electroencephalography (EEG). To be useful, such a device would need to: (a) accurately recreate the real and imaginary components of scalp electrical impedance, (b) contain internal emitters to create electrical dipoles, and (c) be easily replicable across various labs and research groups. Cost-effective materials, which are conductive, repeatable, and easily formed are a missing key enabler for EEG phantoms. Here, we explore the use of ballistics gelatin, an inexpensive, easily-formable and repeatable material, as a putative substrate by examining its electrical properties and physical stability over time. We show that varied concentrations of NaCl salt relative to gelatin powder shifts the phase/frequency response profile, allowing for selective tuning of the material electrical properties.

  7. Design of a novel digital phantom for EIT system calibration.

    Science.gov (United States)

    Li, Nan; Wang, Wei; Xu, Hui

    2011-01-01

    This paper presented the design method of a novel digital phantom for electrical impedance tomography system calibration. By current sensing, voltage generating circuitry and digital processing algorithms implemented in FPGA, the digital phantom can simulate different impedances of tissues. The hardware of the digital phantom mainly consists of current sensing section, voltage generating section, electrodes switching section and a FPGA. Concerning software, the CORDIC algorithm is implemented in the FPGA to realize direct digital synthesis (DDS) technique and related algorithms. Simulation results show that the suggested system exhibits sufficient accuracy in the frequency range 10 Hz to 2 MHz. With the advantages offered by digital techniques, our approach has the potential of speed, accuracy and flexibility of the EIT system calibration process.

  8. Induced sensorimotor brain plasticity controls pain in phantom limb patients

    Science.gov (United States)

    Yanagisawa, Takufumi; Fukuma, Ryohei; Seymour, Ben; Hosomi, Koichi; Kishima, Haruhiko; Shimizu, Takeshi; Yokoi, Hiroshi; Hirata, Masayuki; Yoshimine, Toshiki; Kamitani, Yukiyasu; Saitoh, Youichi

    2016-01-01

    The cause of pain in a phantom limb after partial or complete deafferentation is an important problem. A popular but increasingly controversial theory is that it results from maladaptive reorganization of the sensorimotor cortex, suggesting that experimental induction of further reorganization should affect the pain, especially if it results in functional restoration. Here we use a brain–machine interface (BMI) based on real-time magnetoencephalography signals to reconstruct affected hand movements with a robotic hand. BMI training induces significant plasticity in the sensorimotor cortex, manifested as improved discriminability of movement information and enhanced prosthetic control. Contrary to our expectation that functional restoration would reduce pain, the BMI training with the phantom hand intensifies the pain. In contrast, BMI training designed to dissociate the prosthetic and phantom hands actually reduces pain. These results reveal a functional relevance between sensorimotor cortical plasticity and pain, and may provide a novel treatment with BMI neurofeedback. PMID:27807349

  9. Development of Load Characteristic for The Main Engine and Its PLC Compatible Preparation in Cooperation with The Water Brake as The Generator

    Directory of Open Access Journals (Sweden)

    Mathias Markert

    2017-09-01

    Full Text Available Water brake can be used in any application where a load brake is required on a rotational load. In the engine industry, dynamometer is used in conjunction with a power source and instrumentation to determine engine HP, Torque, and Efficiency ratings with a high degree of accuracy. Water brake are proven durable designs which use water flowing through the absorber to create a load on the engine. Only the amount of water necessary to provide the load is required.Precise load control of the dynamometer is as simple as increasing or decreasing water volume flowing through the dynamometer absorption body. The controls ensure engine load remains stable throughout the duration of the test cycle. Torque, horsepower, RPM, and water temperature are displayed on highly accurate digital instrumentation.Computers can perform both sequential control and feedback control, and typically a single computer will do both in an industrial application. Programmable logic controllers are a type of special purpose microprocessor that replaced many hardware components such as timers and drum sequencers used in relay logic type systems. They can also analyze data and create real time graphical displays for operators and run reports for operators, engineers and management.Industrial control systems are usually used in all over in control system. A distributed control system refers to a control system in which the controllers are spread throughout the system and connect by networks. Smaller automation applications can be implemented with programmable logic controllers.This thesis basically is about designing a programmable logic controller compatible for dynamometer to control speed, power and torque of main engine. To test engine performance in the laboratory, the engine is coupled to a dynamometer. In this thesis dynamometer are used to measure speed, power and torque. One of the most essential role of the control engineer is tuning of controller. Hence the

  10. Luminescence imaging of water during carbon-ion irradiation for range estimation.

    Science.gov (United States)

    Yamamoto, Seiichi; Komori, Masataka; Akagi, Takashi; Yamashita, Tomohiro; Koyama, Shuji; Morishita, Yuki; Sekihara, Eri; Toshito, Toshiyuki

    2016-05-01

    The authors previously reported successful luminescence imaging of water during proton irradiation and its application to range estimation. However, since the feasibility of this approach for carbon-ion irradiation remained unclear, the authors conducted luminescence imaging during carbon-ion irradiation and estimated the ranges. The authors placed a pure-water phantom on the patient couch of a carbon-ion therapy system and measured the luminescence images with a high-sensitivity, cooled charge-coupled device camera during carbon-ion irradiation. The authors also carried out imaging of three types of phantoms (tap-water, an acrylic block, and a plastic scintillator) and compared their intensities and distributions with those of a phantom containing pure-water. The luminescence images of pure-water phantoms during carbon-ion irradiation showed clear Bragg peaks, and the measured carbon-ion ranges from the images were almost the same as those obtained by simulation. The image of the tap-water phantom showed almost the same distribution as that of the pure-water phantom. The acrylic block phantom's luminescence image produced seven times higher luminescence and had a 13% shorter range than that of the water phantoms; the range with the acrylic phantom generally matched the calculated value. The plastic scintillator showed ∼15 000 times higher light than that of water. Luminescence imaging during carbon-ion irradiation of water is not only possible but also a promising method for range estimation in carbon-ion therapy.

  11. Scandinavian Cooperative Advantage

    DEFF Research Database (Denmark)

    Strand, Robert; Freeman, R. Edward

    2015-01-01

    . We conclude by endorsing the expression “Scandinavian cooperative advantage” in an effort to draw attention to the Scandinavian context and encourage the field of strategic management to shift its focus from achieving a competitive advantage toward achieving a cooperative advantage....... of relationships to these historical contributions. Thus, we propose that Scandinavia offers a particularly promising context from which to draw inspiration regarding effective company-stakeholder cooperation and where ample of examples of what is more recently referred to as “creating shared value” can be found...

  12. Design and development of an ultrasound calibration phantom and system

    Science.gov (United States)

    Cheng, Alexis; Ackerman, Martin K.; Chirikjian, Gregory S.; Boctor, Emad M.

    2014-03-01

    Image-guided surgery systems are often used to provide surgeons with informational support. Due to several unique advantages such as ease of use, real-time image acquisition, and no ionizing radiation, ultrasound is a common medical imaging modality used in image-guided surgery systems. To perform advanced forms of guidance with ultrasound, such as virtual image overlays or automated robotic actuation, an ultrasound calibration process must be performed. This process recovers the rigid body transformation between a tracked marker attached to the ultrasound transducer and the ultrasound image. A phantom or model with known geometry is also required. In this work, we design and test an ultrasound calibration phantom and software. The two main considerations in this work are utilizing our knowledge of ultrasound physics to design the phantom and delivering an easy to use calibration process to the user. We explore the use of a three-dimensional printer to create the phantom in its entirety without need for user assembly. We have also developed software to automatically segment the three-dimensional printed rods from the ultrasound image by leveraging knowledge about the shape and scale of the phantom. In this work, we present preliminary results from using this phantom to perform ultrasound calibration. To test the efficacy of our method, we match the projection of the points segmented from the image to the known model and calculate a sum squared difference between each point for several combinations of motion generation and filtering methods. The best performing combination of motion and filtering techniques had an error of 1.56 mm and a standard deviation of 1.02 mm.

  13. Manufacture and image characteristic changes observation by temperature of ultrasound tissue mimicking phantom

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Sang Chull [Dept. of Radiological science, ShinHan university, Dongdocheon (Korea, Republic of)

    2016-06-15

    The purpose of this study is that in measures the acoustic propagate characteristics and temperature sensitivity of ultrasound tissue mimicking phantom(TM phantom). TM phantom manufacture according to the International Electronical Committee(IEC) guidelines for acoustic propagate characteristics of soft tissue. TM phantom was observed to have the image brightness and the image depth penetration decreases changes convergence which was the subject of ultrasound image characteristics in accordance with an external temperature hat the change is reduced in temperature below 22 .deg. C. This study provide a basis to create another TM Phantom and TM Phantom has been determined that it is appropriate for use in more than 22 .deg. C.

  14. “水外交”视角下的中国和下湄公河国家跨界水资源合作%Transboundary Water Cooperation between China and the Lower Mekong Countries from the Perspective of Water Diplomacy

    Institute of Scientific and Technical Information of China (English)

    张励; 卢光盛

    2015-01-01

    Under the background of transboundary cooperation on water resource and scramble for Water Power in-creasing steadily among countries,some international agencies and countries have begun to attach importance to Water Diplomacy and regard it as one of the important means to maintain foreign relations. The issues between Chi-na and the lower Mekong Countries on the transboundary development of the water resource of the Mekong River ur-gently need to be solved through Water Diplomacy. After drawing outline for the research on Water Diplomacy,this article attempts to define Water Diplomacy as the diplomatic means implemented with actions on technical and so-cial levels by one country's government concerning( transboundary or not)collaborative projects on water and de-velopment and exploitation of Soft Water Products. Then taking the definition as breakthrough,the article illumi-nates the problems on the transboundary water cooperation by China with the lower Mekong countries through analy-zing three cases,and meanwhile points out that some reasons contribute to the inadequate implementation of Water Diplomacy by China. In this article,we believe that,in order to resolve internal and external dilemma for exploi-ting the Mekong River,China should improve the Water Diplomacy system,establish community mutually beneficial from transboundary water cooperation,use Integrated Water Resources Management and services of third-party evaluation agencies,and exert more engaging Water Diplomacy.%在跨界水资源合作与国家间“水权力”矛盾与日俱增的背景下,国际机构和部分国家开始重视“水外交”,并将其视为处理对外关系的重要方式之一。中国与下湄公河国家在湄公河跨界水资源开发中的争端也急需通过“水外交”来解决。本文在对“水外交”研究脉络进行梳理的基础上,尝试性地将“水外交”定义为“一国政府围绕(跨界与非跨界)水合作

  15. Space radiation absorbed dose distribution in a human phantom

    Science.gov (United States)

    Badhwar, G. D.; Atwell, W.; Badavi, F. F.; Yang, T. C.; Cleghorn, T. F.

    2002-01-01

    The radiation risk to astronauts has always been based on measurements using passive thermoluminescent dosimeters (TLDs). The skin dose is converted to dose equivalent using an average radiation quality factor based on model calculations. The radiological risk estimates, however, are based on organ and tissue doses. This paper describes results from the first space flight (STS-91, 51.65 degrees inclination and approximately 380 km altitude) of a fully instrumented Alderson Rando phantom torso (with head) to relate the skin dose to organ doses. Spatial distributions of absorbed dose in 34 1-inch-thick sections measured using TLDs are described. There is about a 30% change in dose as one moves from the front to the back of the phantom body. Small active dosimeters were developed specifically to provide time-resolved measurements of absorbed dose rates and quality factors at five organ locations (brain, thyroid, heart/lung, stomach and colon) inside the phantom. Using these dosimeters, it was possible to separate the trapped-proton and the galactic cosmic radiation components of the doses. A tissue-equivalent proportional counter (TEPC) and a charged-particle directional spectrometer (CPDS) were flown next to the phantom torso to provide data on the incident internal radiation environment. Accurate models of the shielding distributions at the site of the TEPC, the CPDS and a scalable Computerized Anatomical Male (CAM) model of the phantom torso were developed. These measurements provided a comprehensive data set to map the dose distribution inside a human phantom, and to assess the accuracy and validity of radiation transport models throughout the human body. The results show that for the conditions in the International Space Station (ISS) orbit during periods near the solar minimum, the ratio of the blood-forming organ dose rate to the skin absorbed dose rate is about 80%, and the ratio of the dose equivalents is almost one. The results show that the GCR model dose

  16. Development of PIMAL: Mathematical Phantom with Moving Arms and Legs

    Energy Technology Data Exchange (ETDEWEB)

    Akkurt, Hatice [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eckerman, Keith F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2007-05-01

    The computational model of the human anatomy (phantom) has gone through many revisions since its initial development in the 1970s. The computational phantom model currently used by the Nuclear Regulatory Commission (NRC) is based on a model published in 1974. Hence, the phantom model used by the NRC staff was missing some organs (e.g., neck, esophagus) and tissues. Further, locations of some organs were inappropriate (e.g., thyroid).Moreover, all the computational phantoms were assumed to be in the vertical-upright position. However, many occupational radiation exposures occur with the worker in other positions. In the first phase of this work, updates on the computational phantom models were reviewed and a revised phantom model, which includes the updates for the relevant organs and compositions, was identified. This revised model was adopted as the starting point for this development work, and hence a series of radiation transport computations, using the Monte Carlo code MCNP5, was performed. The computational results were compared against values reported by the International Commission on Radiation Protection (ICRP) in Publication 74. For some of the organs (e.g., thyroid), there were discrepancies between the computed values and the results reported in ICRP-74. The reasons behind these discrepancies have been investigated and are discussed in this report.Additionally, sensitivity computations were performed to determine the sensitivity of the organ doses for certain parameters, including composition and cross sections used in the simulations. To assess the dose for more realistic exposure configurations, the phantom model was revised to enable flexible positioning of the arms and legs. Furthermore, to reduce the user time for analyses, a graphical user interface (GUI) was developed. The GUI can be used to visualize the positioning of the arms and legs as desired posture is achieved to generate the input file, invoke the computations, and extract the organ dose

  17. Single fiber perfusion phantom for optical coherence tomography

    Science.gov (United States)

    Podlipná, Petra; Kolář, Radim

    2013-06-01

    This paper presents the successful creation of new phantom for optical coherence tomography (OCT) aimed on perfusion simulation. The phantom is created from syringe pump and polypropylene hollow fiber with porous walls embeded in the glass capillary to provide small outer environment. Its function was tested by gold nanorods as a flowing medium and imaged by commercial swept-source OCT system. Results showed that the fiber is permeable for used gold nanorods which are frequently declared as possible contrast agents for OCT and this permeability can be displayed by OCT.

  18. Viscosity-Induced Crossing of the Phantom Barrier

    Directory of Open Access Journals (Sweden)

    Iver Brevik

    2015-09-01

    Full Text Available We show explicitly, by using astrophysical data plus reasonable assumptions for the bulk viscosity in the cosmic fluid, how the magnitude of this viscosity may be high enough to drive the fluid from its position in the quintessence region at present time t = 0 across the barrier w = −1 into the phantom region in the late universe. The phantom barrier is accordingly not a sharp mathematical divide, but rather a fuzzy concept. We also calculate the limiting forms of various thermodynamical quantities, including the rate of entropy production, for a dark energy fluid near the future Big Rip singularity.

  19. CT images of an anthropomorphic and anthropometric male pelvis phantom

    Energy Technology Data Exchange (ETDEWEB)

    Matos, Andrea S.D. de; Campos, Tarcisio P.R. de, E-mail: campos@nuclear.ufmg.b [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares

    2009-07-01

    Actually, among of the most often neoplasm types are the cancer of prostate, bladder and intestine. The incidence of the intestine neoplasm in Brazil is at fourth among the most frequent tumors of the male sex, barely close to the stomach, lung and prostate incidences. Phantoms are objects used as simulators for investigating ionizing radiation transport on humans, especially during radiation therapy or radiological diagnostic. The purpose of this work is the achievement of a set of computerized tomography (CT) images of a male pelvis phantom, with anthropomorphic and anthropometric features. It investigates and analyses the set of phantom CT images in according to a correspondent human pelvis one. The reason to develop a pelvis phantom is the needs of reproducing well established spatial dose distribution in radiation therapy, especially during calibration and protocol setup for various pelvis neoplasms. It aims to produce dose optimization on radiation therapy, improving health tissue protection and keeping control tumor dose. A male pelvis phantom with similar shape made of equivalent tissues was built for simulating the ionizing radiation transport to the human body. At the phantom, pelvis organs were reproduced including the bladder, the intestine, the prostate, the muscular and greasy tissue, as well as the bone tissue and the skin. A set of CT images was carried out in axial thin sections of 2mm thickness. As results, the constituent tissues had a tomography response on Hounsfield scale similar to values found on the human pelvis. Each tissue has its respective Hounsfield value, demonstrated here. The CT images also show that the organs have equivalent anthropometric measures and anthropomorphic features of the radiological human anatomy. The anatomical physical arrangement of the organs is also similar to of the pelvis human male, having the scales of gray and numerical scale of Hounsfield compatible with the scale of the human tissue. The phantom presents

  20. Correction factors for source strength determination in HDR brachytherapy using the in-phantom method

    Energy Technology Data Exchange (ETDEWEB)

    Ubrich, Frank; Engenhart-Cabillic, Rita [University Hospital Giessen-Marburg, Marburg (Germany). Dept. of Radiotherapy and Radiation Oncology; Wulff, Joerg [University of Applied Sciences (THM) Giessen (Germany). Inst. of Medical Physics and Radiation Protection (IMPS); Zink, Klemens [University Hospital Giessen-Marburg, Marburg (Germany). Dept. of Radiotherapy and Radiation Oncology; University of Applied Sciences (THM) Giessen (Germany). Inst. of Medical Physics and Radiation Protection (IMPS)

    2014-09-01

    For the purpose of clinical source strength determination for HDR brachytherapy sources, the German society for Medical Physics (DGMP) recommends in their report 13 the usage of a solid state phantom (Krieger-phantom) with a thimble ionization chamber. In this work, the calibration chain for the determination of the reference air-kerma rate K{sub a,100} and reference dose rate to water D{sub w,1} by ionization chamber measurement in the Krieger-phantom was modeled via Monte Carlo simulations. These calculations were used to determine global correction factors k{sub tot}, which allows a user to directly convert the reading of an ionization chamber calibrated in terms of absorbed dose to water, into the desired quantity K{sub a,100} or D{sub w,1}. The factor k{sub tot} was determined for four available {sup 192}Ir sources and one {sup 60}Co source with three different thimble ionization chambers. Finally, ionization chamber measurements on three μSelectron V2 HDR sources within the Krieger-phantom were performed and K{sub a,100} was determined according to three different methods: (1) using a calibration factor in terms of absorbed dose to water wth the global correction factor (k{sub tot}){sub K{sub a{sub ,{sub 1{sub 0{sub 0}}}}}} according DGMP 13 (2) using a global correction factor calculated via Monte Carlo (3) using a direct reference air-kerma rate calibration factor determined by the national metrology institute PTB. The comparison of Monte Carlo based (k{sub tot}){sub K{sub a{sub ,{sub 1{sub 0{sub 0}}}}}} with those from DGMP 13 showed that the DGMP data were systematically smaller by about 2-2.5%. The experimentally determined (k{sub tot}){sub K{sub a{sub ,{sub 1{sub 0{sub 0}}}}}}, based on the direct K{sub a,100} calibration were also systematically smaller by about 1.5%. Despite of these systematical deviations, the agreement of the different methods was in almost all cases within the 1σ level of confidence of the interval of their respective

  1. Regional Renewable Energy Cooperatives

    Science.gov (United States)

    Hazendonk, P.; Brown, M. B.; Byrne, J. M.; Harrison, T.; Mueller, R.; Peacock, K.; Usher, J.; Yalamova, R.; Kroebel, R.; Larsen, J.; McNaughton, R.

    2014-12-01

    We are building a multidisciplinary research program linking researchers in agriculture, business, earth science, engineering, humanities and social science. Our goal is to match renewable energy supply and reformed energy demands. The program will be focused on (i) understanding and modifying energy demand, (ii) design and implementation of diverse renewable energy networks. Geomatics technology will be used to map existing energy and waste flows on a neighbourhood, municipal, and regional level. Optimal sites and combinations of sites for solar and wind electrical generation (ridges, rooftops, valley walls) will be identified. Geomatics based site and grid analyses will identify best locations for energy production based on efficient production and connectivity to regional grids and transportation. Design of networks for utilization of waste streams of heat, water, animal and human waste for energy production will be investigated. Agriculture, cities and industry produce many waste streams that are not well utilized. Therefore, establishing a renewable energy resource mapping and planning program for electrical generation, waste heat and energy recovery, biomass collection, and biochar, biodiesel and syngas production is critical to regional energy optimization. Electrical storage and demand management are two priorities that will be investigated. Regional scale cooperatives may use electric vehicle batteries and innovations such as pump storage and concentrated solar molten salt heat storage for steam turbine electrical generation. Energy demand management is poorly explored in Canada and elsewhere - our homes and businesses operate on an unrestricted demand. Simple monitoring and energy demand-ranking software can easily reduce peaks demands and move lower ranked uses to non-peak periods, thereby reducing the grid size needed to meet peak demands. Peak demand strains the current energy grid capacity and often requires demand balancing projects and

  2. Cooperative processing data bases

    Science.gov (United States)

    Hasta, Juzar

    1991-01-01

    Cooperative processing for the 1990's using client-server technology is addressed. The main theme is concepts of downsizing from mainframes and minicomputers to workstations on a local area network (LAN). This document is presented in view graph form.

  3. Cooperative Hurricane Network Obs

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Observations from the Cooperative Hurricane Reporting Network (CHURN), a special network of stations that provided observations when tropical cyclones approached the...

  4. Cooperative Transport Planning

    NARCIS (Netherlands)

    Zutt, J.; De Weerdt, M.M.

    2000-01-01

    To test and compare different forms of cooperative planning algorithms developed in the CABS project we use a generic simulator called MARS. Examples in the transportation sector are implemented in this simulator.

  5. Solar cooperatives; Genosse Sonne

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Dierk

    2010-06-15

    Not a boom but a trend: Increasingly, solar power plants and other renewables-based systems are financed by cooperatives. This organizational structure requires long-term strategies and some idealism. (orig.)

  6. Cooperative Weather Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Monthly logs include a daily account of temperature extremes and precipitation, along with snow data at some locations. U.S. Cooperative Observer Program (COOP)...

  7. Cooperative Bacterial Foraging Optimization

    Directory of Open Access Journals (Sweden)

    Hanning Chen

    2009-01-01

    Full Text Available Bacterial Foraging Optimization (BFO is a novel optimization algorithm based on the social foraging behavior of E. coli bacteria. This paper presents a variation on the original BFO algorithm, namely, the Cooperative Bacterial Foraging Optimization (CBFO, which significantly improve the original BFO in solving complex optimization problems. This significant improvement is achieved by applying two cooperative approaches to the original BFO, namely, the serial heterogeneous cooperation on the implicit space decomposition level and the serial heterogeneous cooperation on the hybrid space decomposition level. The experiments compare the performance of two CBFO variants with the original BFO, the standard PSO and a real-coded GA on four widely used benchmark functions. The new method shows a marked improvement in performance over the original BFO and appears to be comparable with the PSO and GA.

  8. Landscape Conservation Cooperatives

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Landscape Conservation Cooperatives (LCCs) are public-private partnerships composed of states, tribes, federal agencies, non-governmental organizations,...

  9. Regional National Cooperative Observer

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA publication dedicated to issues, news and recognition of observers in the National Weather Service Cooperative Observer program. Issues published regionally...

  10. Globalization and economic cooperation

    Directory of Open Access Journals (Sweden)

    Javier Divar

    2006-12-01

    Full Text Available Economic globalization is nothing, really, that the universality of capitalism. Not globalized culture, and economic participation, and human rights, ... has only globalized market. We must react by substituting those materialistic values with cooperative economy.

  11. Cooperative Purchasing Reduces Costs.

    Science.gov (United States)

    Kula, Edwin J.

    1981-01-01

    Several suburban Chicago (Illinois) school districts are members of the South Suburban School Purchasing Cooperative, which serves as a conduit for volume purchases of educational supplies. (Author/MLF)

  12. Cooperating and Prospering

    Institute of Scientific and Technical Information of China (English)

    ZHAO MINGWEN

    2010-01-01

    @@ Since its establish-ment in 2001, the Shanghai Cooperation Organization (SCO)-a re-gional organization grouping China, Russia, Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan-has grown at a notable pace.

  13. Cooperative Fire Protection Agreement

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this Agreement is to provide for cooperation in the prevention, detection and suppression of wildland fires within the protection areas designated in...

  14. Cooperation Beats Conflict

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    China and the Philippines agree to strengthen economic and trade cooperation while minimizing disputes Philippine President Benigno Aquino III recently completed a five-day visit to China, his first state visit to China since he took office last year.

  15. Construction of realistic liver phantoms from patient images using 3D printer and its application in CT image quality assessment

    Science.gov (United States)

    Leng, Shuai; Yu, Lifeng; Vrieze, Thomas; Kuhlmann, Joel; Chen, Baiyu; McCollough, Cynthia H.

    2015-03-01

    The purpose of this study is to use 3D printing techniques to construct a realistic liver phantom with heterogeneous background and anatomic structures from patient CT images, and to use the phantom to assess image quality with filtered back-projection and iterative reconstruction algorithms. Patient CT images were segmented into liver tissues, contrast-enhanced vessels, and liver lesions using commercial software, based on which stereolithography (STL) files were created and sent to a commercial 3D printer. A 3D liver phantom was printed after assigning different printing materials to each object to simulate appropriate attenuation of each segmented object. As high opacity materials are not available for the printer, we printed hollow vessels and filled them with iodine solutions of adjusted concentration to represent enhance levels in contrast-enhanced liver scans. The printed phantom was then placed in a 35×26 cm oblong-shaped water phantom and scanned repeatedly at 4 dose levels. Images were reconstructed using standard filtered back-projection and an iterative reconstruction algorithm with 3 different strength settings. Heterogeneous liver background were observed from the CT images and the difference in CT numbers between lesions and background were representative for low contrast lesions in liver CT studies. CT numbers in vessels filled with iodine solutions represented the enhancement of liver arteries and veins. Images were run through a Channelized Hotelling model observer with Garbor channels and ROC analysis was performed. The AUC values showed performance improvement using the iterative reconstruction algorithm and the amount of improvement increased with strength setting.

  16. Construction of Realistic Liver Phantoms from Patient Images using 3D Printer and Its Application in CT Image Quality Assessment.

    Science.gov (United States)

    Leng, Shuai; Yu, Lifeng; Vrieze, Thomas; Kuhlmann, Joel; Chen, Baiyu; McCollough, Cynthia H

    2015-01-01

    The purpose of this study is to use 3D printing techniques to construct a realistic liver phantom with heterogeneous background and anatomic structures from patient CT images, and to use the phantom to assess image quality with filtered backprojection and iterative reconstruction algorithms. Patient CT images were segmented into liver tissues, contrast-enhanced vessels, and liver lesions using commercial software, based on which stereolithography (STL) files were created and sent to a commercial 3D printer. A 3D liver phantom was printed after assigning different printing materials to each object to simulate appropriate attenuation of each segmented object. As high opacity materials are not available for the printer, we printed hollow vessels and filled them with iodine solutions of adjusted concentration to represent enhance levels in contrast-enhanced liver scans. The printed phantom was then placed in a 35×26 cm oblong-shaped water phantom and scanned repeatedly at 4 dose levels. Images were reconstructed using standard filtered backprojection and an iterative reconstruction algorithm with 3 different strength settings. Heterogeneous liver background were observed from the CT images and the difference in CT numbers between lesions and background were representative for low contrast lesions in liver CT studies. CT numbers in vessels filled with iodine solutions represented the enhancement of liver arteries and veins. Images were run through a Channelized Hotelling model observer with Garbor channels and ROC analysis was performed. The AUC values showed performance improvement using the iterative reconstruction algorithm and the amount of improvement increased with strength setting.

  17. Cooperating mobile robots

    Energy Technology Data Exchange (ETDEWEB)

    Harrington, John J.; Eskridge, Steven E.; Hurtado, John E.; Byrne, Raymond H.

    2004-02-03

    A miniature mobile robot provides a relatively inexpensive mobile robot. A mobile robot for searching an area provides a way for multiple mobile robots in cooperating teams. A robotic system with a team of mobile robots communicating information among each other provides a way to locate a source in cooperation. A mobile robot with a sensor, a communication system, and a processor, provides a way to execute a strategy for searching an area.

  18. Extending Eurasia Security Cooperation

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    After 14 years of development, the Shanghai Cooperation Organization (SCO) , has set its sights on goals for the next de-cade at the 15th meeting of the Council of SCO Heads of State that was held in Ufa, the capital of Russia's Bashkortostan Republic, on July 9-10. The SCO, established in Shanghai in 2001, is committed to building fdendly neighbor rela- tions and maintaining security and stability in the Central Asian region through multilateral cooperation.

  19. Cooperation Without Intervention

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In January, China announced its desire to increase cooperation with African countries by issuing China's African Policy, a paper intended to guide relations with the continent by continuing a non-interventionist and non-ideological strategy. Christopher Mutsvangwa, Zimbabwean Ambassador to China, shared his views of the policy with Beijing Review reporter Ni Yanshuo and answered criticisms of the China-Africa relationship by Western countries that tie cooperation to democracy and human rights.

  20. Cooperation in Construction:

    DEFF Research Database (Denmark)

    Vogelius, Peter; Storgaard, Kresten

    2016-01-01

    The study presents a building project executed by a major Danish construction company, where cooperation and its staging were essential for achieving high productivity and competitiveness. The form of this cooperation is the main theme for the article. The contractor actively changed....... The management logic of the main contractor is interpreted as based on a sociology-inspired understanding focusing on norms and social values rather than on contractual (law) and functional (engineering) logic, which had hitherto been prevalent in Danish construction management....

  1. Global Reserve Cooperation

    Science.gov (United States)

    2011-03-24

    St ra te gy R es ea rc h Pr oj ec t GLOBAL RESERVE COOPERATION BY LIEUTENANT COLONEL PAMELA L. MCGAHA United States Army National Guard...DATES COVERED (From - To) 4. TITLE AND SUBTITLE Global Reserve Cooperation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...decade, the United States, its allies, and partner nations have greatly increased their reliance on Reserve Component forces. This global

  2. Quality control for quantitative multicenter whole-body PET/MR studies: A NEMA image quality phantom study with three current PET/MR systems

    Energy Technology Data Exchange (ETDEWEB)

    Boellaard, Ronald, E-mail: r.boellaard@vumc.nl [Department of Radiology and Nuclear Medicine, VU Medical Center, Amsterdam 1081 HV (Netherlands); European Association of Nuclear Medicine Research Ltd., Vienna 1060 (Austria); European Association of Nuclear Medicine Physics Committee, Vienna 1060 (Austria); Rausch, Ivo; Beyer, Thomas [Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna 1090 (Austria); Delso, Gaspar [GE Healthcare and University Hospital of Zurich, Zurich 8091 (Switzerland); Yaqub, Maqsood [Department of Radiology and Nuclear Medicine, VU Medical Center, Amsterdam 1081 HV (Netherlands); Quick, Harald H. [Institute of Medical Physics, University of Erlangen-Nuremberg, Erlangen 91052 (Germany); Erwin L. Hahn Institute for MRI, University of Duisburg–Essen, Essen 45141 (Germany); High Field and Hybrid MR-Imaging, University Hospital Essen, Essen 45147 (Germany); Sattler, Bernhard [Department of Nuclear Medicine, University Hospital of Leipzig, Leipzig 04103 (Germany); European Association of Nuclear Medicine Physics Committee, Vienna 1060 (Austria)

    2015-10-15

    Purpose: Integrated positron emission tomography/magnetic resonance (PET/MR) systems derive the PET attenuation correction (AC) from dedicated MR sequences. While MR-AC performs reasonably well in clinical patient imaging, it may fail for phantom-based quality control (QC). The authors assess the applicability of different protocols for PET QC in multicenter PET/MR imaging. Methods: The National Electrical Manufacturers Association NU 2 2007 image quality phantom was imaged on three combined PET/MR systems: a Philips Ingenuity TF PET/MR, a Siemens Biograph mMR, and a GE SIGNA PET/MR (prototype) system. The phantom was filled according to the EANM FDG-PET/CT guideline 1.0 and scanned for 5 min over 1 bed. Two MR-AC imaging protocols were tested: standard clinical procedures and a dedicated protocol for phantom tests. Depending on the system, the dedicated phantom protocol employs a two-class (water and air) segmentation of the MR data or a CT-based template. Differences in attenuation- and SUV recovery coefficients (RC) are reported. PET/CT-based simulations were performed to simulate the various artifacts seen in the AC maps (μ-map) and their impact on the accuracy of phantom-based QC. Results: Clinical MR-AC protocols caused substantial errors and artifacts in the AC maps, resulting in underestimations of the reconstructed PET activity of up to 27%, depending on the PET/MR system. Using dedicated phantom MR-AC protocols, PET bias was reduced to −8%. Mean and max SUV RC met EARL multicenter PET performance specifications for most contrast objects, but only when using the dedicated phantom protocol. Simulations confirmed the bias in experimental data to be caused by incorrect AC maps resulting from the use of clinical MR-AC protocols. Conclusions: Phantom-based quality control of PET/MR systems in a multicenter, multivendor setting may be performed with sufficient accuracy, but only when dedicated phantom acquisition and processing protocols are used for

  3. A three-dimensional head-and-neck phantom for validation of multimodality deformable image registration for adaptive radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Singhrao, Kamal; Kirby, Neil; Pouliot, Jean, E-mail: jpouliot@radonc.ucsf.edu [Department of Radiation Oncology, University of California San Francisco, San Francisco, California 94143-1708 (United States)

    2014-12-15

    Purpose: To develop a three-dimensional (3D) deformable head-and-neck (H and N) phantom with realistic tissue contrast for both kilovoltage (kV) and megavoltage (MV) imaging modalities and use it to objectively evaluate deformable image registration (DIR) algorithms. Methods: The phantom represents H and N patient anatomy. It is constructed from thermoplastic, which becomes pliable in boiling water, and hardened epoxy resin. Using a system of additives, the Hounsfield unit (HU) values of these materials were tuned to mimic anatomy for both kV and MV imaging. The phantom opens along a sagittal midsection to reveal radiotransparent markers, which were used to characterize the phantom deformation. The deformed and undeformed phantoms were scanned with kV and MV imaging modalities. Additionally, a calibration curve was created to change the HUs of the MV scans to be similar to kV HUs, (MC). The extracted ground-truth deformation was then compared to the results of two commercially available DIR algorithms, from Velocity Medical Solutions and MIM software. Results: The phantom produced a 3D deformation, representing neck flexion, with a magnitude of up to 8 mm and was able to represent tissue HUs for both kV and MV imaging modalities. The two tested deformation algorithms yielded vastly different results. For kV–kV registration, MIM produced mean and maximum errors of 1.8 and 11.5 mm, respectively. These same numbers for Velocity were 2.4 and 7.1 mm, respectively. For MV–MV, kV–MV, and kV–MC Velocity produced similar mean and maximum error values. MIM, however, produced gross errors for all three of these scenarios, with maximum errors ranging from 33.4 to 41.6 mm. Conclusions: The application of DIR across different imaging modalities is particularly difficult, due to differences in tissue HUs and the presence of imaging artifacts. For this reason, DIR algorithms must be validated specifically for this purpose. The developed H and N phantom is an effective tool

  4. Design and application of a structured phantom for detection performance comparison between breast tomosynthesis and digital mammography

    Science.gov (United States)

    Cockmartin, L.; Marshall, N. W.; Zhang, G.; Lemmens, K.; Shaheen, E.; Van Ongeval, C.; Fredenberg, E.; Dance, D. R.; Salvagnini, E.; Michielsen, K.; Bosmans, H.

    2017-02-01

    This paper introduces and applies a structured phantom with inserted target objects for the comparison of detection performance of digital breast tomosynthesis (DBT) against 2D full field digital mammography (FFDM). The phantom consists of a 48 mm thick breast-shaped polymethyl methacrylate (PMMA) container filled with water and PMMA spheres of different diameters. Three-dimensionally (3D) printed spiculated masses (diameter range: 3.8-9.7 mm) and non-spiculated masses (1.6-6.2 mm) along with microcalcifications (90-250 µm) were inserted as targets. Reproducibility of the phantom application was studied on a single system using 30 acquisitions. Next, the phantom was evaluated on five different combined FFDM & DBT systems and target detection was compared for FFDM and DBT modes. Ten phantom images in both FFDM and DBT modes were acquired on these 5 systems using automatic exposure control. Five readers evaluated target detectability. Images were read with the four-alternative forced-choice (4-AFC) paradigm, with always one segment including a target and 3 normal background segments. The percentage of correct responses (PC) was assessed based on 10 trials of each reader for each object type, size and imaging modality. Additionally, detection threshold diameters at 62.5 PC were assessed via non-linear regression fitting of the psychometric curve. The reproducibility study showed no significant differences in PC values. Evaluation of target detection in FFDM showed that microcalcification detection thresholds ranged between 110 and 118 µm and were similar compared to the detection in DBT (range of 106-158 µm). In DBT, detection of both mass types increased significantly (p  =  0.0001 and p  =  0.0002 for non-spiculated and spiculated masses respectively) compared to FFDM, achieving almost 100% detection for all spiculated mass diameters. In conclusion, a structured phantom with inserted targets was able to show evidence for detectability

  5. Scientific-technical cooperation with Russia. Transient analyses for alternative types of water-cooled reactors. Final report; WTZ mit Russland. Transientenanalysen fuer wassergekuehlte Kernreaktoren. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Rohde, Ulrich [Forschungszentrum Dresden-Rossendorf (Germany). Inst. fuer Sicherheitsforschung; Kozmenkov, Yaroslav [Forschungszentrum Dresden-Rossendorf (Germany). Inst. fuer Sicherheitsforschung; Institute of Physics and Power Engineering, Obninsk (Russian Federation); Pivovarov, Valeri; Matveev, Yurij [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    2010-12-15

    The recently developed multi-group version DYN3D-MG of the reactor dynamics code DYN3D has been qualified for applications to water-cooled reactor concepts different from industrial PWR and BWR. An extended DYN3D version was applied to the graphite-moderated pressure tube reactor EGP-6 (NPP Bilibino) and conceptual design studies of an advanced Boiling Water Reactor with reduced moderation (RMWR) as well as the RUTA-70 reactor for low temperature heat supply. Concerning the RUTA reactor, safe heat removal by natural circulation of the coolant at low pressure has to be shown. For the corresponding validation of thermo-hydraulic system codes like ATHLET and RELAP5, experiments on flashing-induced natural circulation instabilities performed at the CIRCUS test facility at the TU Delft were simulated using the RELAP5 code. For the application to alternative water-cooled reactors, DYN3D model extensions and modifications were implemented, in particular adaptations of heat conduction and heat transfer models. Performing code-to-code comparisons with the Russian fine-mesh neutron diffusion code ACADEM contributed to the verification of DYN3D-MG. Validation has been performed by calculating reactor dynamics experiments at the NPP Bilibino. For the reactors EGP-6, RMWR and RUTA, analyses of various protected and unprotected control rod withdrawal and ejection transients were performed. The beyond design basis accident (BDBA) scenario ''Coast-down of all main coolant pumps at nominal power without scram'' for the RUTA reactor was analyzed using the code complexes DYN3D/ATHLET and DYN3D/RELAP5. It was shown, that the reactor passes over to a save asymptotic state at reduced power with coolant natural circulation. Analyzing the BDBA ''Unprotected withdrawal of a control rod group'' for the RMWR, the safety against Departure from Nucleate Boiling (DNB) could not be shown with the necessary confidence. Finally, conclusions have been drawn

  6. Development of an Ultra-Low-Cost Solar Water Heater: Cooperative Research and Development Final Report, CRADA Number CRD-12-487

    Energy Technology Data Exchange (ETDEWEB)

    Merrigan, Tim [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-02-17

    NREL and RhoTech will collaborate to bring long-lived, ultra-low-cost, high-performance solar water heaters (SWH) to market readiness. An existing RhoTech design uses seam-welded polymer thin films to make an unglazed thermosiphon, and this design will be modified to improve durability through ultraviolet and overheat protection, and to improve performance by adding a glazing to the collector. Two generations of the new glazed systems will be tested in the field, resulting in a robust market-ready SWH design that can be installed for under $1,000 without rebates.

  7. Cooperation and depressive symptoms.

    Science.gov (United States)

    Brendan Clark, C; Thorne, Christopher B; Hardy, Sonya; Cropsey, Karen L

    2013-09-25

    Deficits in pro-social cooperation are common in many individuals with mental illnesses such as depression. For decades, researchers have used economic game paradigms to compare cross-cultural cooperative behavior. However, research using economic games to assess cooperative behavior in clinical populations is in the early stages. We hypothesized that individuals with greater depressive symptoms would struggle to maintain reciprocity in iterative games, but not in single-iteration games measuring personal values. Participants (n=41) played four computer-based economic games (prisoner's dilemma, the public goods game, the ultimatum game, and the trust game) measuring different aspects of cooperation. Participants completed the Depression Anxiety and Stress Scale (DASS) and other measures of personality and demographics. Analyses assessed the relationships between game performance and psychological distress as measured by the DASS. Significant correlations were found between game performance and depressive symptoms, but not symptoms of anxiety or stress. Performance in the prisoner's dilemma and public goods game was significantly related to depression in a linear regression even when known associations with depressive affect such as age, gender, race, education, marital status, and neuroticism were controlled for. Depressive symptoms were associated with an inability to sustain reciprocal cooperation. Participants showed the predicted deficits in cooperation in these economic games. Economic games show the potential for assessing the social deficits associated with depressive symptoms. © 2013 Elsevier B.V. All rights reserved.

  8. The co-production of a "relevant" expertise – administrative and scientific cooperation in the French water policies elaboration and implementation since the 1990s

    Directory of Open Access Journals (Sweden)

    J. F. Deroubaix

    2008-08-01

    Full Text Available This paper aims at understanding the social and political uses of the principle of integrated management and its possible impacts on the elaboration and implementation processes of public policies in the French water management sector. The academic and political innovations developed by scientists and agents of the administration these last 25 years are analysed, using some of the theoretical tools developed by the science studies and public policy analysis. We first focus on the construction of intellectual public policy communities such as the GIP Hydro systems, at the origin of large interdisciplinary research programs in the 1990s. A common cognitive framework is clearly built during this period on the good governance of the aquatic ecosystems and on the corresponding needs and practices of research. The second part of the paper focuses on the possibilities to build political communities and more or less integrated expertises in the decision making processes concerning various issues related to water management. Eutrophication and its inscription on the French political agenda is a very significant case for analysing the difficulty to build such a political community. On the contrary, when there is an opportunity for policy evaluation, which was the case concerning the management of wetlands in France or the implementation of compulsory flows on the French rivers, these communities can emerge. However, the type of integrated expertise and management proposed in these cases of policy evaluations much depends on their methodological choices.

  9. The co-production of a "relevant" expertise administrative and scientific cooperation in the French water policies elaboration and implementation since the 1990s

    Science.gov (United States)

    Deroubaix, J. F.

    2008-08-01

    This paper aims at understanding the social and political uses of the principle of integrated management and its possible impacts on the elaboration and implementation processes of public policies in the French water management sector. The academic and political innovations developed by scientists and agents of the administration these last 25 years are analysed, using some of the theoretical tools developed by the science studies and public policy analysis. We first focus on the construction of intellectual public policy communities such as the GIP Hydro systems, at the origin of large interdisciplinary research programs in the 1990s. A common cognitive framework is clearly built during this period on the good governance of the aquatic ecosystems and on the corresponding needs and practices of research. The second part of the paper focuses on the possibilities to build political communities and more or less integrated expertises in the decision making processes concerning various issues related to water management. Eutrophication and its inscription on the French political agenda is a very significant case for analysing the difficulty to build such a political community. On the contrary, when there is an opportunity for policy evaluation, which was the case concerning the management of wetlands in France or the implementation of compulsory flows on the French rivers, these communities can emerge. However, the type of integrated expertise and management proposed in these cases of policy evaluations much depends on their methodological choices.

  10. SU-E-T-172: Characterization of TLD-100 (LiF:Mg,Ti) Microcube Energy Response in a Cylindrical Chamber Phantom

    Energy Technology Data Exchange (ETDEWEB)

    Desai, V; Hammer, C; Kunugi, K; Culberson, W; DeWerd, L [University of WI-Madison/ADCL, Madison, WI (United States)

    2015-06-15

    Purpose: To characterize the energy response of TLD-100 microcubes inside a Virtual Water chamber phantom. Methods: Four TLD microcubes were placed inside a water-proof Virtual Water (VW) chamber phantom and irradiated to a known dose on a Varian linac in a 1D water tank. These chamber phantoms were then replaced by TLD-100 chips inside a separate VW paddle and irradiated to the same dose. Each energy response reading was calculated as light output per unit dose in nC/cGy and normalized to a calibration set irradiated to the same dose in 60Co. The differences in response between the TLD chips and microcubes were then analyzed. Results: Across all energies, the average microcube response was less sensitive to energy than the average chip response with both falling consistently within 2.8% of previously established values in the literature Conclusion: TLD microcubes showed a lower average sensitivity to energy than their TLD chip counterparts. The use of TLD-100 microcubes inside the chamber phantom was validated against TLD-100 chips inside of VW paddles.

  11. MO-C-17A-05: A Three-Dimensional Head-And-Neck Phantom for Validation of Kilovoltage- and Megavoltage-Based Deformable Image Registration

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, N; Singhrao, K; Pouliot, J [UC San Francisco, San Francisco, CA (United States)

    2014-06-15

    Purpose: To develop a three-dimensional (3D) deformable head-and-neck (H and N) phantom with realistic tissue contrast for both kilovoltage and megavoltage computed tomography and use it to objectively evaluate deformable image registration (DIR) algorithms. Methods: The phantom represents H and N patient anatomy. It is constructed from thermoplastic, which becomes pliable in boiling water, and hardened epoxy resin. Using a system of additives, the Hounsfield unit (HU) values of these materials were tuned to mimic anatomy for both kilovoltage (kV) and megavoltage (MV) imaging. The phantom opened along a sagittal midsection to reveal nonradiopaque markers, which were used to characterize the phantom deformation. The deformed and undeformed phantom was scanned with kV and MV computed tomography. Additionally, a calibration curve was created to change the HUs of the MV scans to be similar to kV HUs, (MC). The extracted ground-truth deformation was then compared to the results of two commercially available DIR algorithms, from Velocity Medical Solutions and MIM Software. Results: The phantom produced a 3D deformation, representing neck flexion, with a magnitude of up to 8 mm and was able represent tissue HUs for both kV and MV imaging modalities. The two tested deformation algorithms yielded vastly different results. For kV-kV registration, MIM made the lowest mean error, and Velocity made the lowest maximum error. For MV-MV, kV-MV, and kV-MC Velocity produced both the lowest mean and lowest maximum errors. Conclusion: The application of DIR across different imaging modalities is particularly difficult, due to differences in tissue HUs and the presence of imaging artifacts. For this reason, DIR algorithms must be validated specifically for this purpose. The developed H and N phantom is an effective tool for this purpose.

  12. Phantom shocks in patients with implantable cardioverter defibrillator

    DEFF Research Database (Denmark)

    Berg, Selina Kikkenborg; Moons, Philip; Zwisler, Ann-Dorthe;

    2013-01-01

    of phantom shocks.METHODS AND RESULTS: The design was secondary explorative analyses of data from a randomized controlled trial. One hundred and ninety-six patients with first-time ICD implantation (79% male, mean age 58 years) were randomized (1 : 1) to either combined rehabilitation or a control group...

  13. Role of phantoms in progress of medical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tanada, Shuji [National Inst. of Radiological Sciences, Chiba (Japan)

    1998-09-01

    Importance of phantoms in medical imaging was discussed from the aspect of quality control/assurance which consisting of accuracy management and performance assessment of the imaging apparatuses. Phantoms have played significant roles in progress of nuclear medicine. Medical images would be classified in the two: morphological ones as represented by X-ray CT and MRI and functional ones by PET and SPECT. The roles of phantoms played are those for evaluation of organ/tissue exposure dose due to the administered radiopharmaceuticals, for evaluation of accuracy management and performance assessment of apparatuses (I.e., homogeneity and stability of the sensitivity, linearity between measured value and radioactivity and assessment of spacial resolution in the reconstructed images), for evaluation of reconstructed images as quantitatively-assessed functional ones, for evaluation of cross calibration among multiple apparatuses and for validation of tracer kinetic model analysis. In summary, phantoms in medical imaging are useful in the assessment of accurate performance, in the assurance of reliability of results, in the comparison of quantitative repeated or inter-individual examination results and in the quantitative evaluation of the function of small structures like the basal ganglia and thalamus. (K.H.)

  14. Improvement of skeleton conversion in ICRP reference phantom conversion project

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhao Jun; Yeom, Yeon Soo; Thang, Nguyen Tat; Kim, Han Sung; Han, Min Cheol; Kim, Chan Hyeong [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of); Kim, Seong Hoon [Dept. of Radiation Oncology, College of Medicine, Hanyang University, Seoul (Korea, Republic of)

    2014-11-15

    In the previous skeleton conversion, most bones were directly converted from the ICRP voxel phantoms by using the 3D rendering method whereas several complex-shape bones (cranium, ribs, spines, feet, and hands) were not able to be directly converted. We alternatively employed the corresponding well-defined polygonal models and attempted to adjust them to match the voxel models. However, this approach was unsatisfactory. The shapes of the alternative models were significantly different from those of the voxel models, making it virtually impossible to exactly match the voxel models as shown in Fig. 3 (left). In order to overcome the difficulty in the complex bone conversion, the present study developed a new conversion method and converted these complex bones voxel models of the ICRP male phantom to polygonal models. The present study developed the new conversion method and successfully improved polygonal models for cranium, ribs, and spines for the ICRP male phantom. The new conversion method will be also applied to the complex bone conversion for the ICRP female phantom as well as other complex organ conversion in the future.

  15. A computational phantom of head and neck - SISCODES

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larissa; Trindade, Bruno Machado; Campos, Tarcisio Passos Ribeiro [Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares]. E-mail: larissa.thompson@ig.com.br; bmtrindade@yahoo.com; campos@nuclear.ufmg.br

    2007-07-01

    A computational voxel model of a head and neck adult male was built through the SISCODES code, in order to complement and to optimize the radiotherapic treatment in head and neck cancer, in terms of dosimetric evaluation and prediction. This computational simulator object, namely computational phantom, is a useful tool for the elaboration and simulation of the three-dimensional radiation planning. The present phantom was assembled based on information generated by photographic images of the visible human project. The images were digitalized and converted one by one to a matrix of voxel, in which tissues and its respective chemical composition were identified, with the helping of a biomedical and nuclear data bank including in SISCODES. A computational simulation of an external beam mimicking a Co-60 irradiator was prepared, reproducing a radiation window equivalent to one found in a lateral irradiation of a nasopharyngeal tumour in situ. Absorbed dose evaluation in the internal regions of the phantom are presented and demonstrated through spatial dose distribution, superimposed with the 2D phantom sections. The present article illustrates the possibility of generating information of the spatial dose distribution including all adjacent tissues, far from tumour, improving the radiodosimetry and creating the possibility of investigating neurological deficits, dysphagia, and speaking and hearing alterations, non evaluated in the present stage of radiation therapy of head and neck. (author)

  16. Gravitational Quasinormal Modes of Regular Phantom Black Hole

    Directory of Open Access Journals (Sweden)

    Jin Li

    2017-01-01

    Full Text Available We investigate the gravitational quasinormal modes (QNMs for a type of regular black hole (BH known as phantom BH, which is a static self-gravitating solution of a minimally coupled phantom scalar field with a potential. The studies are carried out for three different spacetimes: asymptotically flat, de Sitter (dS, and anti-de Sitter (AdS. In order to consider the standard odd parity and even parity of gravitational perturbations, the corresponding master equations are derived. The QNMs are discussed by evaluating the temporal evolution of the perturbation field which, in turn, provides direct information on the stability of BH spacetime. It is found that in asymptotically flat, dS, and AdS spacetimes the gravitational perturbations have similar characteristics for both odd and even parities. The decay rate of perturbation is strongly dependent on the scale parameter b, which measures the coupling strength between phantom scalar field and the gravity. Furthermore, through the analysis of Hawking radiation, it is shown that the thermodynamics of such regular phantom BH is also influenced by b. The obtained results might shed some light on the quantum interpretation of QNM perturbation.

  17. Generation of anatomically realistic numerical phantoms for optoacoustic breast imaging

    Science.gov (United States)

    Lou, Yang; Mitsuhashi, Kenji; Appleton, Catherine M.; Oraevsky, Alexander; Anastasio, Mark A.

    2016-03-01

    Because optoacoustic tomography (OAT) can provide functional information based on hemoglobin contrast, it is a promising imaging modality for breast cancer diagnosis. Developing an effective OAT breast imaging system requires balancing multiple design constraints, which can be expensive and time-consuming. Therefore, computer- simulation studies are often conducted to facilitate this task. However, most existing computer-simulation studies of OAT breast imaging employ simple phantoms such as spheres or cylinders that over-simplify the complex anatomical structures in breasts, thus limiting the value of these studies in guiding real-world system design. In this work, we propose a method to generate realistic numerical breast phantoms for OAT research based on clinical magnetic resonance imaging (MRI) data. The phantoms include a skin layer that defines breast-air boundary, major vessel branches that affect light absorption in the breast, and fatty tissue and fibroglandular tissue whose acoustical heterogeneity perturbs acoustic wave propagation. By assigning realistic optical and acoustic parameters to different tissue types, we establish both optic and acoustic breast phantoms, which will be exported into standard data formats for cross-platform usage.

  18. Fast 2D phantom dosimetry for scanning proton beams

    NARCIS (Netherlands)

    Boon, SN; van Luijk, P; Schippers, JM; Meertens, H; Denis, JM; Vynckier, S; Medin, J; Grusell, E

    1998-01-01

    A quality control system especially designed for dosimetry in scanning proton beams has been designed and tested. The system consists of a scintillating screen (Gd2O2S:Tb), mounted at the beam-exit side of a phantom, and observed by a low noise CCD camera with a long integration time. The purpose of

  19. Control volume based hydrocephalus research; a phantom study

    Science.gov (United States)

    Cohen, Benjamin; Voorhees, Abram; Madsen, Joseph; Wei, Timothy

    2009-11-01

    Hydrocephalus is a complex spectrum of neurophysiological disorders involving perturbation of the intracranial contents; primarily increased intraventricular cerebrospinal fluid (CSF) volume and intracranial pressure are observed. CSF dynamics are highly coupled to the cerebral blood flows and pressures as well as the mechanical properties of the brain. Hydrocephalus, as such, is a very complex biological problem. We propose integral control volume analysis as a method of tracking these important interactions using mass and momentum conservation principles. As a first step in applying this methodology in humans, an in vitro phantom is used as a simplified model of the intracranial space. The phantom's design consists of a rigid container filled with a compressible gel. Within the gel a hollow spherical cavity represents the ventricular system and a cylindrical passage represents the spinal canal. A computer controlled piston pump supplies sinusoidal volume fluctuations into and out of the flow phantom. MRI is used to measure fluid velocity and volume change as functions of time. Independent pressure measurements and momentum flow rate measurements are used to calibrate the MRI data. These data are used as a framework for future work with live patients and normal individuals. Flow and pressure measurements on the flow phantom will be presented through the control volume framework.

  20. MRXCAT: Realistic numerical phantoms for cardiovascular magnetic resonance.

    Science.gov (United States)

    Wissmann, Lukas; Santelli, Claudio; Segars, William P; Kozerke, Sebastian

    2014-08-20

    Computer simulations are important for validating novel image acquisition and reconstruction strategies. In cardiovascular magnetic resonance (CMR), numerical simulations need to combine anatomical information and the effects of cardiac and/or respiratory motion. To this end, a framework for realistic CMR simulations is proposed and its use for image reconstruction from undersampled data is demonstrated. The extended Cardiac-Torso (XCAT) anatomical phantom framework with various motion options was used as a basis for the numerical phantoms. Different tissue, dynamic contrast and signal models, multiple receiver coils and noise are simulated. Arbitrary trajectories and undersampled acquisition can be selected. The utility of the framework is demonstrated for accelerated cine and first-pass myocardial perfusion imaging using k-t PCA and k-t SPARSE. MRXCAT phantoms allow for realistic simulation of CMR including optional cardiac and respiratory motion. Example reconstructions from simulated undersampled k-t parallel imaging demonstrate the feasibility of simulated acquisition and reconstruction using the presented framework. Myocardial blood flow assessment from simulated myocardial perfusion images highlights the suitability of MRXCAT for quantitative post-processing simulation. The proposed MRXCAT phantom framework enables versatile and realistic simulations of CMR including breathhold and free-breathing acquisitions.

  1. Human torso phantom for imaging of heart with realistic modes of cardiac and respiratory motion

    Science.gov (United States)

    Boutchko, Rostyslav; Balakrishnan, Karthikayan; Gullberg, Grant T; O& #x27; Neil, James P

    2013-09-17

    A human torso phantom and its construction, wherein the phantom mimics respiratory and cardiac cycles in a human allowing acquisition of medical imaging data under conditions simulating patient cardiac and respiratory motion.

  2. Construction of computer tomographic phantoms and their application in radiology and radiation protection

    Energy Technology Data Exchange (ETDEWEB)

    Zankl, M.; Veit, R.; Williams, G.; Schneider, K.; Fendel, H.; Petoussi, N.; Drexler, G.

    1988-05-01

    In order to assess human organ doses for risk estimates under natural and man made radiation exposure conditions, human phantoms have to be used. As an improvement to the mathematical anthropomorphic phantoms, a new family of phantoms is proposed, constructed from Computer Tomographic (CT) data. A technique is developed which allows any physical phantom to be converted into computer files to be used for several applications. The new human phantoms present advantages towards the location and shape of the organs, in particular the hard bone and bone marrow. The CT phantoms were used to construct three dimensional images of high resolution; some examples are given and their potential is discussed. The use of CT phantoms is also demonstrated to assess accurately the proportion of bone marrow in the skeleton. Finally, the use of CT phantoms for Monte Carlo (MC) calculations of doses resulting from various photon exposures in radiology and radiation protection is discussed.

  3. Preliminary evaluation of specific absorbed fraction (SAF) in ICRP reference phantom conversion project

    Energy Technology Data Exchange (ETDEWEB)

    Thang, Nguyen Tat; Yeom, Yeon Soo; Han, Min Cheol; Jun, Wang Zhao; Kim, Han Sung; Kim, Seong Hoon; Kim, Chan Hyeong [Hanyang University, Seoul (Korea, Republic of)

    2014-11-15

    The ICRP reference phantoms, due to their low voxel resolutions, provide incorrect dose values for weakly penetrating radiations. To overcome the limitations, we are now converting the ICRPvoxel phantoms to polygonal surface models in order to develop the polygonal surface version of the ICRP reference phantoms. The ultimate goal of the conversion project is to develop a set of polygonal surface ICRP phantoms which provide correct dose values for weakly penetrating radiations while providing identical dose values with those of the ICRP reference phantoms for highly penetrating radiations. It was confirmed that indeed the current ICRP male polygonal phantom showed generally good agreement with the ICRP male voxel phantom following the objective of the ICRP phantom conversion project. However, relatively large discrepancies were found in the colon doses at 0.03 MeV. We believe that the discrepancies could be sufficiently reduced by adjusting the colon polygonal model to be more similar to the voxel model in the further study.

  4. Design and development of a telerehabilitation platform for patients with phantom limb pain

    NARCIS (Netherlands)

    Andreas Rothgangel; Susy Braun; Rob Smeets; Anna Beurskens

    2017-01-01

    Background: Phantom limb pain is a frequent and persistent problem following amputation. Achieving sustainable favorable effects on phantom limb pain requires therapeutic interventions such as mirror therapy that target maladaptive neuroplastic changes in the central nervous system. Unfortunately,

  5. Report on research of calculus fragmentation by HIFU-induced cavitation in Tsinghua University: 1. Effects of tissue-mimicking phantom

    Science.gov (United States)

    Zuo, Z. G.; Liu, S. H.

    2012-11-01

    Study of the acoustic attenuation through human tissues was carried out, in order to accurately evaluate the damaging power of the generated cavitation cloud. Tissue phantom was made, with acoustic properties (acoustic speed and acoustic attenuation factor) similar to human tissues. Preliminary results show that, with the increase of intensity and acting time of the HIFU acoustic waves, the depths of the craters increase rapidly, while the radii of the craters increase mildly. Mass loss of the artificial stones in phantom is less than in water (about 50%), indicating considerable energy dissipation in tissues.

  6. Photoacoustic perfusion measurements: a comparison with power Doppler in phantoms

    Science.gov (United States)

    Heres, H. M.; Arabul, M. Ü.; Tchang, B. C.; van de Vosse, F. N.; Rutten, M. C.; Lopata, R. G.

    2015-03-01

    Ultrasound-based measurements using Doppler, contrast, and more recently photoacoustics (PA), have emerged as techniques for tissue perfusion measurements. In this study, the feasibility of in vitro perfusion measurements with a fully integrated, hand-held, photoacoustic probe was investigated and compared to Power Doppler (PD). Three cylindrical polyvinyl alcohol (PVA) phantoms were made (diameter = 15 mm) containing 100, 200 and 400 parallel polysulfone tubes (diameter = 0.2 mm), resulting in a perfused cross-sectional area of 1.8, 3.6 and 7.1% respectively. Each phantom was perfused with porcine blood (15 mL/min). Cross-sectional PA images (λ = 805nm, frame rate = 10Hz) and PD images (PRF = 750Hz) were acquired with a MyLab One and MyLab 70 scanner (Esaote, NL), respectively. Data were averaged over 70 frames. The average PA signal intensity was calculated in a region-of-interest of 4 mm by 6 mm. The percentage of colored PD pixels was measured in the entire phantom region. The average signal intensity of the PA images increased linearly with perfusion density, being 0.54 (+/- 0.01), 0.56 (+/- 0.01), 0.58 (+/- 0.01) with an average background signal of 0.53 in the three phantoms, respectively. For PD, the percentage of colored pixels in the phantom area (1.5% (+/- 0.2%), 4.4% (+/- 0.2%), 13.7% (+/- 0.8%)) also increased linearly. The preliminary results suggest that PA, like PD, is capable of detecting an increase of blood volume in tissue. In the future, in vivo measurements will be explored, although validation will be more complex.

  7. "Imprisoned" in pain: analyzing personal experiences of phantom pain.

    Science.gov (United States)

    Nortvedt, Finn; Engelsrud, Gunn

    2014-11-01

    This article explores the phenomenon of "phantom pain." The analysis is based on personal experiences elicited from individuals who have lost a limb or live with a paralyzed body part. Our study reveals that the ways in which these individuals express their pain experience is an integral aspect of that experience. The material consists of interviews undertaken with men who are living with phantom pain resulting from a traumatic injury. The phenomenological analysis is inspired by Zahavi (J Conscious Stud 8(5-7):151-167, 2001) and Merleau-Ponty (Phenomenology of perception. Routledge and Kegan Paul, London, 1962/2000). On a descriptive level the metaphors these patients invoke to describe their condition reveal immense suffering, such as a feeling of being invaded by insects or of their skin being scorched and stripped from their body. Such metaphors express a dimension of experience concerning the self that is in pain and others whom the sufferer relates to through this pain, as well as the agony that this pain inflicts in the world of lived experience. This pain has had a profound impact on their lives and altered their relationship with self (body), others and the world. Their phantom pain has become a reminder of their formerly intact and functioning body; they describe the contrast between their past and present body as an ambiguous and disturbing experience. We conclude that these sensitive and personalized experiences of phantom pain illuminates how acts of expression--spoken pain--constitute a fundamental dimension of a first-person perspective which contribute to the field of knowledge about "phantom pain".

  8. Possible association between phantom vibration syndrome and occupational burnout

    Directory of Open Access Journals (Sweden)

    Chen CP

    2014-12-01

    Full Text Available Chao-Pen Chen,1 Chi-Cheng Wu,2 Li-Ren Chang,3 Yu-Hsuan Lin4 1Department of Education, National Taiwan University Hospital, 2Department of Family Medicine, Min-Sheng General Hospital, Taoyuan City, 3Department of Psychiatry, National Taiwan University, College of Medicine, 4Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan Background: Phantom vibration syndrome (PVS and phantom ringing syndrome (PRS occur in many cell phone users. Previous studies have indicated an association between PVS/PRS and job stress. The aim of this study was to determine if PVS/PRS were also associated with occupational burnout.Methods: This was a cross-sectional study of 384 employees of a high-tech company in northern Taiwan. They all completed a phantom vibration and ringing questionnaire, the Hospital Anxiety and Depression Scale, and the Chinese version of the Occupational Burnout Inventory.Results: Significantly more women and people with at least a college education were in the population with PRS and PVS, respectively. Anxiety and depression had no associations with PVS/PRS. Higher scores for personal fatigue, job fatigue, and service target fatigue had an independent impact on the presence of PVS, but only a higher score for service target fatigue had an independent impact on the presence of PRS.Conclusion: The independent association between work-related burnout and PVS/PRS suggests that PVS/PRS may be a harbinger of mental stress or a component of the clinical burnout syndrome, and may even be a more convenient and accurate predictor of occupational burnout. Keywords: phantom vibration syndrome, phantom ringing syndrome, occupational burnout

  9. Developing a Verification and Training Phantom for Gynecological Brachytherapy System

    Directory of Open Access Journals (Sweden)

    Mahbobeh Nazarnejad

    2012-03-01

    Full Text Available Introduction Dosimetric accuracy is a major issue in the quality assurance (QA program for treatment planning systems (TPS. An important contribution to this process has been a proper dosimetry method to guarantee the accuracy of delivered dose to the tumor. In brachytherapy (BT of gynecological (Gyn cancer it is usual to insert a combination of tandem and ovoid applicators with a complicated geometry which makes their dosimetry verification difficult and important. Therefore, evaluation and verification of dose distribution is necessary for accurate dose delivery to the patients. Materials and Methods The solid phantom was made from Perspex slabs as a tool for intracavitary brachytherapy dosimetric QA. Film dosimetry (EDR2 was done for a combination of ovoid and tandem applicators introduced by Flexitron brachytherapy system. Treatment planning was also done with Flexiplan 3D-TPS to irradiate films sandwiched between phantom slabs. Isodose curves obtained from treatment planning system and the films were compared with each other in 2D and 3D manners. Results The brachytherapy solid phantom was constructed with slabs. It was possible to insert tandems and ovoids loaded with radioactive source of Ir-192 subsequently. Relative error was 3-8.6% and average relative error was 5.08% in comparison with the films and TPS isodose curves. Conclusion Our results showed that the difference between TPS and the measurements is well within the acceptable boundaries and below the action level according to AAPM TG.45. Our findings showed that this phantom after minor corrections can be used as a method of choice for inter-comparison analysis of TPS and to fill the existing gap for accurate QA program in intracavitary brachytherapy. The constructed phantom also showed that it can be a valuable tool for verification of accurate dose delivery to the patients as well as training for brachytherapy residents and physics students.

  10. Posttraumatic syringomyelia: volumetric phantom and patient studies using MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Freund, Michael; Habicht, Dirk; Kalvine, Kira; Sartor, Klaus [Department of Neuroradiology, Medical School, University of Heidelberg (Germany); Aschoff, Alfred [Department of Neurosurgery, Medical School, University of Heidelberg (Germany)

    2002-12-01

    The purpose of this study was to determine the volume of posttraumatic syringomyelia (PTS) based on standard MRI data acquisitions, and to compare the volumes with the neurological deficits of the patients. Firstly, phantom studies were performed using routine T1- (T1W; TR 500 ms, TE 13 ms) spin-echo (SE) images, 3D gradient-echo (GE) images and T2-weighted (T2W) turbo spin-echo (TSE) images (TR 3000 ms, TE 130 ms), in the sagittal plane. The slices were interleaved so that there was no gap. Twelve phantoms simulating a PTS were constructed and filled with fluid. Each volume was exactly measured immediately prior to filling (volumes: 3600-74,000 mm{sup 3}, mean 27,500 mm{sup 3}). In the clinical study 32 patients with PTS were examined using the same protocol. Patients were supine and a phased-array coil was used. The phantom studies revealed measurement errors of within 35%. There were problems defining the boundaries in the small and irregular phantoms as well as in small and irregular PTS, and due to the partial-volume averaging effect. The two small irregular phantoms could only be measured on the axial images. The T2W images in the axial plane showed the best results: measurement accuracy 92%. In the clinical study all examinations were technically successful. The volumes of the PTS ranged between 200 and 19,800 mm{sup 3}; the mean volume was 4075 mm{sup 3}. Our initial results show that the volume measurement of a PTS using standard MRI sequences can help generate more objective and accurate measures of spinal cord lesions, and this may enhance the sensitivity of MRI in detecting disease progression or regression after treatment. (orig.)

  11. Floating worlds and their phantoms in the aftermath of social catastrophes.

    Science.gov (United States)

    Kimbles, Samuel

    2017-02-01

    In this paper the author describes certain kinds of images (phantoms) that appear in the aftermath of social catastrophes. These phantoms come with an underlying narrative structure, which the author describes as phantom narratives. Phantom narratives show how the unconscious, working at the group and individual levels, provides political and social contexts within which the individual may find a different kind of containment for these catastrophes. In this way their suffering may be potentially processed psychologically and related to symbolically.

  12. Use of Calcitonin in Recalcitrant Phantom Limb Pain Complicated by Heterotopic Ossification

    Directory of Open Access Journals (Sweden)

    Ricardo Viana

    2015-01-01

    Full Text Available A common complication following amputation is phantom sensation, which may include experiencing pain in the phantom limb. This study details the management of phantom limb pain in a 72-year-old man, in whom comorbid heterotopic ossification was present. In addition, the authors provide a review of the literature regarding phantom limb pain management, and summarize the current understanding of heterotopic ossification and its possible link to peripheral nerve injury.

  13. Fundamental Limits of Cooperation

    CERN Document Server

    Lozano, Angel; Andrews, Jeffrey G

    2012-01-01

    Cooperation is viewed as a key ingredient for interference management in wireless systems. This paper shows that cooperation has fundamental limitations. The main result is that even full cooperation between transmitters cannot in general change an interference-limited network to a noise-limited network. The key idea is that there exists a spectral efficiency upper bound that is independent of the transmit power. First, a spectral efficiency upper bound is established for systems that rely on pilot-assisted channel estimation; in this framework, cooperation is shown to be possible only within clusters of limited size, which are subject to out-of-cluster interference whose power scales with that of the in-cluster signals. Second, an upper bound is also shown to exist when cooperation is through noncoherent communication; thus, the spectral efficiency limitation is not a by-product of the reliance on pilot-assisted channel estimation. Consequently, existing literature that routinely assumes the high-power spect...

  14. Atypical supernumerary phantom limb and phantom limb pain in a patient with spinal cord injury: case report.

    Science.gov (United States)

    Choi, Ja Young; Kim, Hyo In; Lee, Kil Chan; Han, Zee-A

    2013-12-01

    Supernumerary phantom limb (SPL) resulting from spinal cord lesions are very rare, with only sporadic and brief descriptions in the literature. Furthermore, the reported cases of SPL typically occurred in neurologically incomplete spinal cord patients. Here, we report a rare case of SPL with phantom limb pain that occurred after traumatic spinal cord injury in a neurologically complete patient. After a traffic accident, a 43-year-old man suffered a complete spinal cord injury with a C6 neurologic level of injury. SPL and associated phantom limb pain occurred 6 days after trauma onset. The patient felt the presence of an additional pair of legs that originated at the hip joints and extended medially, at equal lengths to the paralyzed legs. The intensity of SPL and associated phantom limb pain subsequently decreased after visual-tactile stimulation treatment, in which the patient visually identified the paralyzed limbs and then gently tapped them with a wooden stick. This improvement continued over the 2 months of inpatient treatment at our hospital and the presence of the SPLs was reduced to 20% of the real paralyzed legs. This is the first comprehensive report on SPLs of the lower extremities after neurologically complete spinal cord injury.

  15. Phantom hand and wrist movements in upper limb amputees are slow but naturally controlled movements.

    Science.gov (United States)

    De Graaf, J B; Jarrassé, N; Nicol, C; Touillet, A; Coyle, T; Maynard, L; Martinet, N; Paysant, J

    2016-01-15

    After limb amputation, patients often wake up with a vivid perception of the presence of the missing limb, called "phantom limb". Phantom limbs have mostly been studied with respect to pain sensation. But patients can experience many other phantom sensations, including voluntary movements. The goal of the present study was to quantify phantom movement kinematics and relate these to intact limb kinematics and to the time elapsed since amputation. Six upper arm and two forearm amputees with various delays since amputation (6months to 32years) performed phantom finger, hand and wrist movements at self-chosen comfortable velocities. The kinematics of the phantom movements was indirectly obtained via the intact limb that synchronously mimicked the phantom limb movements, using a Cyberglove® for measuring finger movements and an inertial measurement unit for wrist movements. Results show that the execution of phantom movements is perceived as "natural" but effortful. The types of phantom movements that can be performed are variable between the patients but they could all perform thumb flexion/extension and global hand opening/closure. Finger extension movements appeared to be 24% faster than finger flexion movements. Neither the number of types of phantom movements that can be executed nor the kinematic characteristics were related to the elapsed time since amputation, highlighting the persistence of post-amputation neural adaptation. We hypothesize that the perceived slowness of phantom movements is related to altered proprioceptive feedback that cannot be recalibrated by lack of visual feedback during phantom movement execution.

  16. Experimental and computational development of a natural breast phantom for dosimetry studies

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Luciana B.; Campos, Tarcisio P.R., E-mail: lucibn19@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)

    2013-07-01

    This paper describes the experimental and computational development of a natural breast phantom, anthropomorphic and anthropometric for studies in dosimetry of brachytherapy and teletherapy of breast. The natural breast phantom developed corresponding to fibroadipose breasts of women aged 30 to 50 years, presenting radiographically medium density. The experimental breast phantom was constituted of three tissue-equivalents (TE's): glandular TE, adipose TE and skin TE. These TE's were developed according to chemical composition of human breast and present radiological response to exposure. Completed the construction of experimental breast phantom this was mounted on a thorax phantom previously developed by the research group NRI/UFMG. Then the computational breast phantom was constructed by performing a computed tomography (CT) by axial slices of the chest phantom. Through the images generated by CT a computational model of voxels of the thorax phantom was developed by SISCODES computational program, being the computational breast phantom represented by the same TE's of the experimental breast phantom. The images generated by CT allowed evaluating the radiological equivalence of the tissues. The breast phantom is being used in studies of experimental dosimetry both in brachytherapy as in teletherapy of breast. Dosimetry studies by MCNP-5 code using the computational model of the phantom breast are in progress. (author)

  17. 33 CFR 334.460 - Cooper River and tributaries at Charleston, SC.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Cooper River and tributaries at... ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS § 334.460 Cooper River and tributaries at Charleston, SC. (a) The areas: (1) That portion of the Cooper River beginning on the west...

  18. 33 CFR 334.470 - Cooper River and Charleston Harbor, S.C.; restricted areas.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Cooper River and Charleston....470 Cooper River and Charleston Harbor, S.C.; restricted areas. (a) The restricted areas. (1) Area No. 1 is that portion of the Cooper River beginning near the westerly shore north of Shipyard Creek...

  19. Cooperative IASCC Research (CIR) Program

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, J.L. [Electric Power Research Inst., Palo Alto, CA (United States). Nuclear Power Group

    1998-03-01

    Irradiation assisted stress corrosion cracking (IASCC) describes intergranular environmental cracking of material exposed to ionizing radiation. The implications of IASCC are significant, both in terms of repair and outage costs as well as the potential for cracking in components that may be extremely difficult to repair or replace. Significant advancements have been made in the understanding of IASCC. However, it is clear that major unknowns persist and must be understood and quantified before the life of a reactor component at risk from IASCC can be predicted or significantly extended. Although individual organizations are continuing to effectively address IASCC, it became apparent that a more direct form of cooperation would be more timely and efficient in addressing the technical issues. Thus in 1995 EPRI formed the Cooperative IASCC Research (CIR) Program. This is a cooperative, jointly funded effort with participants from eight countries providing financial support and technical oversight. The efforts of the CIR Program are directed at the highest priority questions in the areas of material susceptibility, water chemistry and material stress. Major research areas of the Program are: (1) evaluation of IASCC mechanisms, (2) development of methodology for predicting IASCC, and (3) quantification of irradiation effects on metallurgy, mechanics and electrochemistry. Studies to evaluate various IASCC mechanisms include work to better understand the possible roles of radiation-induced segregation (RIS), radiation microstructure, bulk and localized deformation effects, overall effects on strength and ductility, hydrogen and helium effects, and others. Experiments are being conducted to isolate individual effects and determine the relative importance of each in the overall IASCC mechanism. Screening tests will be followed by detailed testing to identify the contribution of each effect over a range of conditions. The paper describes the completed and ongoing work being

  20. SU-E-CAMPUS-T-03: Development and Implementation of An Anthropomorphic Pediatric Spine Phantom for the Assessment of Craniospinal Irradiation Procedures in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, D; Summers, P; Followill, D; Sahoo, N; Mahajan, A; Stingo, F; Kry, S [UT MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-15

    Purpose: To design an anthropomorphic pediatric spine phantom for use in the evaluation of proton therapy facilities for clinical trial participation by the Imaging and Radiation Oncology Core (IROC) Houston QA Center (formerly RPC). Methods: This phantom was designed to perform an end-to-end audit of the proton spine treatment process, including simulation, dose calculation by the treatment planning system (TPS), and proton treatment delivery. The design incorporated materials simulating the thoracic spinal column of a pediatric patient, along with two thermoluminescent dosimeter (TLD)-100 capsules and radiochromic film embedded in the phantom for dose evaluation. Fourteen potential materials were tested to determine relative proton stopping power (RSP) and Hounsfield unit (HU) values. Each material was CT scanned at 120kVp, and the RSP was obtained from depth ionization scans using the Zebra multilayer ion chamber (MLIC) at two energies: 160 MeV and 250 MeV. To determine tissue equivalency, the measured RSP for each material was compared to the RSP calculated by the Eclipse TPS for a given HU. Results: The materials selected as bone, tissue, and cartilage substitutes were Techron HPV Bearing Grade (Boedeker Plastics, Inc.), solid water, and blue water, respectively. The RSP values did not differ by more than 1.8% between the two energies. The measured RSP for each selected material agreed with the RSP calculated by the Eclipse TPS within 1.2%. Conclusion: An anthropomorphic pediatric proton spine phantom was designed to evaluate proton therapy delivery. The inclusion of multiple tissue substitutes increases heterogeneity and the level of difficulty for institutions to successfully treat the phantom. The following attributes will be evaluated: absolute dose agreement, distal range, field width, junction match and right/left dose profile alignment. The phantom will be tested at several institutions using a 5% dose agreement criterion, and a 5%/3mm gamma analysis